tag:theconversation.com,2011:/global/topics/hearing-6409/articlesHearing – The Conversation2024-03-04T19:22:02Ztag:theconversation.com,2011:article/2239792024-03-04T19:22:02Z2024-03-04T19:22:02ZHearing loss is twice as common in Australia’s lowest income groups, our research shows<figure><img src="https://images.theconversation.com/files/578501/original/file-20240228-16-1eydkt.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5760%2C3828&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/older-man-woman-pensioners-hearing-problem-1150312364">adriaticfoto/Shutterstock</a></span></figcaption></figure><p>Around <a href="https://www.healthdirect.gov.au/hearing-loss">one in six Australians</a> has some form of hearing loss, ranging from mild to complete hearing loss. That figure is expected to grow to <a href="https://www.connecthearing.com.au/about-connect-hearing/ews/facts-figures-hearing-loss-australia/">one in four</a> by 2050, due in a large part to the country’s ageing population.</p>
<p>Hearing loss affects communication and social engagement and limits educational and employment opportunities. Effective treatment for hearing loss is available in the form of communication training (for example, lipreading and auditory training), hearing aids and other devices. </p>
<p>But the <a href="https://www.connecthearing.com.au/about-connect-hearing/ews/facts-figures-hearing-loss-australia/">uptake of treatment</a> is low. In Australia, <a href="https://www.ndis.gov.au/news/4838-securing-future-hearing-services">publicly subsidised hearing care</a> is available predominantly only to children, young people and retirement-age people on a pension. Adults of working age are mostly <a href="https://hcia.com.au/hcia-hearing-for-life/">not eligible</a> for hearing health care under the government’s <a href="https://www.health.gov.au/our-work/hearing-services-program">Hearing Services Program</a>.</p>
<p>Our recent study published in the journal <a href="https://doi.org/10.1097/AUD.0000000000001375%20">Ear and Hearing</a> showed, for the first time, that working-age Australians from lower socioeconomic backgrounds are at much greater risk of hearing loss than those from higher socioeconomic backgrounds.</p>
<p>We believe the lack of socially subsidised hearing care for adults of working age results in poor detection and care for hearing loss among people from disadvantaged backgrounds. This in turn exacerbates social inequalities.</p>
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Read more:
<a href="https://theconversation.com/overcharged-for-hearing-aids-australias-audiology-industry-isnt-rogue-but-needs-improvement-61850">Overcharged for hearing aids? Australia's audiology industry isn't rogue, but needs improvement</a>
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<h2>Population data shows hearing inequality</h2>
<p>We analysed a large data set called the Household, Income and Labour Dynamics in Australia (<a href="https://melbourneinstitute.unimelb.edu.au/hilda">HILDA</a>) survey that collects information on various aspects of people’s lives, including health and hearing loss. </p>
<p>Using a HILDA sub-sample of 10,719 working-age Australians, we evaluated whether self-reported hearing loss was more common among people from lower socioeconomic backgrounds than for those from higher socioeconomic backgrounds between 2008 and 2018. </p>
<p>Relying on self-reported hearing data instead of information from hearing tests is one limitation of our paper. However, self-reported hearing tends to underestimate actual rates of hearing impairment, so the hearing loss rates we reported are likely an underestimate.</p>
<p>We also wanted to find out whether people from lower socioeconomic backgrounds were more likely to develop hearing loss in the long run.</p>
<figure class="align-center ">
<img alt="A boy wearing a hearing aid is playing." src="https://images.theconversation.com/files/578502/original/file-20240228-20-ira21d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/578502/original/file-20240228-20-ira21d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/578502/original/file-20240228-20-ira21d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/578502/original/file-20240228-20-ira21d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/578502/original/file-20240228-20-ira21d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/578502/original/file-20240228-20-ira21d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/578502/original/file-20240228-20-ira21d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Hearing care is publicly subsidised for children.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/boy-hearing-aids-cochlear-implants-playing-1643924338">mady70/Shutterstock</a></span>
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<p>We found people in the lowest income groups were more than twice as likely to have hearing loss than those in the highest income groups. Further, hearing loss was 1.5 times as common among people living in the most deprived neighbourhoods than in the most affluent areas. </p>
<p>For people reporting no hearing loss at the beginning of the study, after 11 years of follow up, those from a more deprived socioeconomic background were much more likely to develop hearing loss. For example, a lack of post secondary education was associated with a more than 1.5 times increased risk of developing hearing loss compared to those who achieved a bachelor’s degree or above.</p>
<p>Overall, men were <a href="https://rest.neptune-prod.its.unimelb.edu.au/server/api/core/bitstreams/338e8071-4e77-53f0-aa0e-d15ad4d07742/content">more likely</a> to have hearing loss than women. As seen in the figure below, this gap is largest for people of low socioeconomic status.</p>
<p><iframe id="xghf3" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/xghf3/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<h2>Why are disadvantaged groups more likely to experience hearing loss?</h2>
<p>There are several possible reasons hearing loss is more common among people from low socioeconomic backgrounds. Noise exposure is one of the <a href="https://www.aafp.org/pubs/afp/issues/2000/0501/p2749.html">biggest risks</a> for hearing loss and people from low socioeconomic backgrounds may be more likely to be exposed to <a href="https://pubmed.ncbi.nlm.nih.gov/22767358/">damaging levels of noise</a> in jobs in mining, construction, manufacturing, and agriculture.</p>
<p>Lifestyle factors which may be more prevalent in lower socioeconomic communities such as smoking, unhealthy diet, and a lack of regular exercise <a href="https://pubmed.ncbi.nlm.nih.gov/37107253/">are also related</a> to the risk of hearing loss. </p>
<p>Finally, people with lower incomes may face challenges in accessing timely hearing care, alongside competing health needs, which could lead to missed identification of treatable ear disease.</p>
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Read more:
<a href="https://theconversation.com/pumping-loud-music-is-putting-more-than-1-billion-young-people-at-risk-of-hearing-loss-194537">Pumping loud music is putting more than 1 billion young people at risk of hearing loss</a>
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<h2>Why does this disparity in hearing loss matter?</h2>
<p>We like to think of Australia as an egalitarian society – the land of the fair go. But nearly half of people in Australia with hearing loss <a href="https://hcia.com.au/wp-content/uploads/2024/01/Hearing_for_Life.pdf">are of working age</a> and mostly ineligible for publicly funded hearing services. </p>
<p>Hearing aids with a private hearing care provider cost from around A$1,000 up to more than $4,000 <a href="https://www.hearingchoices.com.au/hearing-aids/hearing-aid-prices/">for higher-end devices</a>. Most people need two hearing aids. </p>
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<img alt="A builder using a grinder machine at a construction site." src="https://images.theconversation.com/files/578503/original/file-20240228-16-3gtske.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/578503/original/file-20240228-16-3gtske.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/578503/original/file-20240228-16-3gtske.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/578503/original/file-20240228-16-3gtske.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/578503/original/file-20240228-16-3gtske.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/578503/original/file-20240228-16-3gtske.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/578503/original/file-20240228-16-3gtske.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Hearing loss might be more common in low income groups because they’re exposed to more noise at work.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/builder-worker-grinder-machine-cutting-metal-86230687">Dmitry Kalinovsky/Shutterstock</a></span>
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<p>Lack of access to affordable hearing care for working-age adults on low incomes comes with an economic as well as a social cost.</p>
<p>Previous economic analysis estimated hearing loss was responsible for financial costs of around <a href="https://hcia.com.au/wp-content/uploads/2024/01/Hearing_for_Life.pdf">$20 billion in 2019–20</a> in Australia. The largest component of these costs was productivity losses (unemployment, under-employment and Jobseeker social security payment costs) among working-age adults.</p>
<h2>Providing affordable hearing care for all Australians</h2>
<p>Lack of affordable hearing care for working-age adults from lower socioeconomic backgrounds may significantly exacerbate the impact of hearing loss among deprived communities and worsen social inequalities.</p>
<p>Recently, the federal government has been considering extending publicly subsidised hearing services to <a href="https://www.health.gov.au/sites/default/files/documents/2021/10/report-of-the-independent-review-of-the-hearing-services-program-report.docx">lower income working age Australians</a>. We believe reforming the current government Hearing Services Program and expanding eligibility to this group could not only promote a more inclusive, fairer and healthier society but may also yield overall cost savings by reducing lost productivity.</p>
<p>All Australians should have access to affordable hearing care to have sufficient functional hearing to achieve their potential in life. That’s the land of the fair go.</p><img src="https://counter.theconversation.com/content/223979/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mohammad Nure Alam acknowledges funding from Macquarie University.</span></em></p><p class="fine-print"><em><span>Kompal Sinha acknowledges funding from Macquarie University. </span></em></p><p class="fine-print"><em><span>Piers Dawes receives funding from the National Health and Medical Research Council. Piers Dawes represents the University of Queensland on the Hearing Health Sector Alliance. </span></em></p>This is both a result of social inequality, and an issue that could widen disparities further.Mohammad Nure Alam, PhD Candidate in Economics, Macquarie UniversityKompal Sinha, Associate Professor, Department of Economics, Macquarie UniversityPiers Dawes, Professor, School of Health and Rehabilitation Sciences, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2193782023-12-18T13:23:43Z2023-12-18T13:23:43ZDo you hear what I see? How blindness changes how you process the sound of movement<figure><img src="https://images.theconversation.com/files/565875/original/file-20231214-23-s4v8j4.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2048%2C1462&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Sighted people would have a hard time crossing the street by sound alone.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/full-length-of-blind-woman-crossing-road-with-stick-royalty-free-image/1210268422">Maskot/DigitalVision via Getty Images</a></span></figcaption></figure><p>Almost nothing in the world is still. Toddlers dash across the living room. Cars zip across the street. Motion is one of the most <a href="https://doi.org/10.1088/0954-898X/6/3/003">important features in the environment</a>; the ability to predict the movement of objects in the world is often directly related to survival – whether it’s a gazelle detecting the slow creep of a lion or a driver merging across four lanes of traffic.</p>
<p>Motion is so important that the primate brain evolved a dedicated system for processing visual movement, known as the middle temporal cortex, <a href="https://doi.org/10.1016/B978-0-444-53860-4.00005-2">over 50 million years ago</a>. This region of the brain contains neurons specialized for detecting moving objects. These <a href="https://doi.org/10.1093/acrefore/9780190264086.013.76">motion detectors</a> compute the information needed to track objects as they continuously change their location over time, then sends signals about the moving world to other regions of the brain, such as those involved in planning muscle movements.</p>
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<a href="https://images.theconversation.com/files/565877/original/file-20231214-21-e83re8.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagram of brain with the middle temporal gyrus — a strip on the bottom side of the brain — highlighted in yellow" src="https://images.theconversation.com/files/565877/original/file-20231214-21-e83re8.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/565877/original/file-20231214-21-e83re8.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=347&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565877/original/file-20231214-21-e83re8.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=347&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565877/original/file-20231214-21-e83re8.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=347&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565877/original/file-20231214-21-e83re8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=436&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565877/original/file-20231214-21-e83re8.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=436&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565877/original/file-20231214-21-e83re8.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=436&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">The middle temporal cortex is involved in processing visual movement.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Gray726_middle_temporal_gyrus.png">Gray, vectorized by Mysid, colored by was_a_bee/Wikimedia Commons</a></span>
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<p>It’s easy to assume that you see and hear motion in a similar way. However, exactly how the brain processes auditory motion has been an <a href="https://doi.org/10.1016/j.brainres.2007.03.003">open scientific question</a> for at least 30 years. This debate centers on two ideas: One supports the existence of specialized auditory motion detectors similar to those found in visual motion, and the other suggests that people hear object motion as discrete snapshots.</p>
<p>As <a href="https://scholar.google.com/citations?user=WtPLYRIAAAAJ&hl=en">computational</a> <a href="https://scholar.google.com/citations?user=5LuGpVgAAAAJ&hl=en">neuroscientists</a>, we became curious when we noticed a blind woman confidently crossing a busy intersection. <a href="https://faculty.washington.edu/ionefine/">Our laboratory</a> has spent the past 20 years examining where auditory motion is represented in the brains of blind individuals.</p>
<p>For sighted people, crossing a busy street based on hearing alone is an impossible task, because their brains are used to <a href="https://doi.org/10.1364/JOSAA.20.001391">relying on vision</a> to understand where things are. As anyone who has tried to find a beeping cellphone that’s fallen behind the sofa knows, sighted people have a very limited ability to pinpoint the location or movement of objects based on auditory information.</p>
<p>Yet people who become blind are able to make sense of the moving world using only sound. How do people hear motion, and how is this changed by being blind?</p>
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<a href="https://images.theconversation.com/files/565879/original/file-20231214-27-s4v8j4.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Aerial view of pedestrians on a crosswalk, a few cars waiting at the edges" src="https://images.theconversation.com/files/565879/original/file-20231214-27-s4v8j4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565879/original/file-20231214-27-s4v8j4.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565879/original/file-20231214-27-s4v8j4.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565879/original/file-20231214-27-s4v8j4.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565879/original/file-20231214-27-s4v8j4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565879/original/file-20231214-27-s4v8j4.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565879/original/file-20231214-27-s4v8j4.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">People who are blind are better able to track auditory motion in noisy conditions compared with sighted people.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/pedestrians-on-zebra-crossing-new-york-city-royalty-free-image/1048763642">Orbon Alija/E+ via Getty Images</a></span>
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<h2>Crossing a busy street by sound alone</h2>
<p>In our <a href="https://doi.org/10.1073/pnas.2310156120">recently published study</a> in the journal PNAS, we tackled the question of how blind people hear motion by asking a slightly different version of it: Are blind people better at perceiving auditory motion? And if so, why?</p>
<p>To answer this question, we used a simple task where we asked study participants to judge the direction of a sound that moved left or right. This moving sound was embedded in bursts of stationary background noise resembling radio static that were randomly positioned in space and time.</p>
<p>Our first question was whether blind participants would be better at the task. We measured how loud the auditory motion had to be for participants to be able to perform the task correctly 65% of the time. We found that the hearing of blind participants was no different from that of sighted participants. However, the blind participants were able to determine the direction of the auditory motion at <a href="https://doi.org/10.1073/pnas.2310156120">much quieter levels</a> than sighted participants. In other words, people who became blind early in life are better at hearing the auditory motion of objects within a noisy world. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/565949/original/file-20231215-28-skziw1.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="showing motion of object from one corner of a plane to another, where the blind participant is able to detect the position of the object more closely than the sighted participant" src="https://images.theconversation.com/files/565949/original/file-20231215-28-skziw1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565949/original/file-20231215-28-skziw1.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565949/original/file-20231215-28-skziw1.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565949/original/file-20231215-28-skziw1.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565949/original/file-20231215-28-skziw1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565949/original/file-20231215-28-skziw1.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565949/original/file-20231215-28-skziw1.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Blind participants were able to determine the position of the object as it starts and stops moving more closely than sighted participants.</span>
<span class="attribution"><a class="source" href="https://doi.org/10.1073/pnas.2310156120">Ione Fine and Woon Ju Park</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
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<p>We then examined how the noise bursts interfered with the ability to tell the direction of motion. For both sighted and blind participants, only the noise bursts at the beginning and the end of each trial had an effect on performance. These results show that people do not track objects continuously using sound: Instead they infer auditory motion from the <a href="https://doi.org/10.1073/pnas.2310156120">location of sounds at their beginning and end</a>, more consistent with the snapshot hypothesis. </p>
<p>Both blind and sighted people inferred movement from the start and stop of sounds. So why were blind people so much better at understanding auditory motion than sighted people? </p>
<p>Further analysis of the effects of background noise on the ability to track auditory motion showed that blind participants were affected only by noise bursts occurring at the <a href="https://doi.org/10.1073/pnas.2310156120">same locations in space and moments in time</a> as the onset and offset of the moving sound. This means that they were more sensitive to the beginning and end of the actual auditory motion and less susceptible to irrelevant noise bursts.</p>
<h2>When you hear what I see</h2>
<p>As any parent of a blind child will tell you, understanding motion is just <a href="https://nfb.org/our-community/parents-blind-children">one of the many ways</a> that blind children learn to interact with the world using different cues and actions. </p>
<p>A sighted baby recognizes their parent’s face as they approach the crib, while a blind baby recognizes the sound of their footsteps. A sighted toddler looks toward the dog to attract their parent’s attention, while a blind toddler might <a href="https://doi.org/10.1017/S0954579403000142">pull their parent’s hand</a> in the direction of the barking. </p>
<p>Understanding the ability of blind people to <a href="https://doi.org/10.1146/annurev-vision-102016-061241">learn how to successfully interact</a> with a world designed for the sighted provides a unique appreciation of the extraordinary flexibility of the human brain.</p><img src="https://counter.theconversation.com/content/219378/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>This work was supported by NIH National Eye Institute Grants R01EY014645 (to I.F.) </span></em></p><p class="fine-print"><em><span>Woon Ju Park receives funding from an NIH National Eye Institute Grant K99EY034546 and was supported by a Weill Neurohub Postdoctoral Fellowship. </span></em></p>Detecting and tracking motion is key to survival. The ability to extract auditory information from a noisy environment changes when your brain isn’t wired to rely on vision.Ione Fine, Professor of Psychology, University of WashingtonWoon Ju Park, Research Scientist, University of WashingtonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1928102023-01-31T13:15:48Z2023-01-31T13:15:48ZMini creatures with mighty voices know their audience and focus on a single frequency<figure><img src="https://images.theconversation.com/files/506448/original/file-20230125-20-qo2fa8.jpg?ixlib=rb-1.1.0&rect=799%2C1210%2C3639%2C1815&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The coquí frog, *Eleutherodactylus coqui*, is loud enough to wake people at night.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/atardecerboricua/6412552985/in/photolist-nqd2wM-siBCx-9U7tfN-3dc6jS-nqYftj-2obkoYQ-nsGGeX-2ob6cY8-3dc5gN-2obhqNm-2ob784C-4wSjbL-MJzjq-8FRYs3-8FNNcF-8FNMP8-8FNLHa-K2daUb-aLE1An-D9pPx5-bvssQd-dK5Cia-dKb61y-dKb6nj-CD8QSt-K2daXs">Éktor/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>In the cloud forests of South America, amid the constant cacophony of bird and insect noise, a deafening blare pierces through the background from time to time. Belonging to the loudest known bird, the white bellbird, <em>Procnias albus</em>, this sound would be painful to humans listening nearby and capable of causing <a href="https://www.cdc.gov/nceh/hearing_loss/what_noises_cause_hearing_loss.html">immediate hearing damage from about a yard away</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/dvK-DujvpSY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Listen to the world’s loudest bird call.</span></figcaption>
</figure>
<p><a href="https://doi.org/10.1016/j.cub.2019.09.028">Made exclusively by males serenading females</a>, these vocalizations can reach peak levels of more than 120 decibels on the sound pressure level scale (dB SPL), which is equivalent to a <a href="https://planenerd.com/decibels-of-a-jet-engine/">jet aircraft taking off from 100 yards away</a>. <a href="https://doi.org/10.1016/j.cub.2019.09.028">The female bellbird listens some distance from the male</a>, presumably trading off being close enough to assess his quality as a mate without damaging her ears. </p>
<p>I study the <a href="https://scholar.google.com/citations?hl=en&user=IekcMzwAAAAJ">hearing ability of animals and the sounds they make</a> to communicate. A great number of calls exist throughout the animal kingdom – and many are used to attract mates or defend territories. Evolution has favored those able to make sounds efficiently. The <a href="https://doi.org/10.1006/anbe.2003.2093">louder and more focused</a> the energy in the call and the <a href="https://doi.org/10.1007/978-1-4612-1182-2_7">closer in pitch</a> it is to the intended listener’s optimal hearing range, the farther away a potential mate or rival will hear it. </p>
<p>Many large mammals, such as singing whales, roaring lions and rumbling elephants, <a href="https://doi.org/10.1007/BF00299740">produce loud low-pitched sounds</a> that travel especially well through most habitats. Because of their petite physical size, small animals are not capable of making these far-reaching low-frequency sounds. </p>
<p>As a workaround, a number of small creatures have found ingenious ways to deliver their messages loudly, despite their size.</p>
<h2>Ultrasonic calls</h2>
<p>Human ears are most sensitive to the <a href="https://www.researchgate.net/figure/Audiogram-showing-the-average-human-threshold-for-pure-tones-obtained-in-a-sound-field_fig2_6597029">highest notes on a piano</a> – about 4 kHz – a unit of measurement that is the physical metric for pitch. Anything above 20 kHz is considered ultrasonic – undetectable to human ears. But such sounds are not undetectable to all ears.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/506443/original/file-20230125-7959-o0r30p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up photo of a bat's head showing large and elaborately ridged ears." src="https://images.theconversation.com/files/506443/original/file-20230125-7959-o0r30p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/506443/original/file-20230125-7959-o0r30p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/506443/original/file-20230125-7959-o0r30p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/506443/original/file-20230125-7959-o0r30p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/506443/original/file-20230125-7959-o0r30p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/506443/original/file-20230125-7959-o0r30p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/506443/original/file-20230125-7959-o0r30p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The greater bulldog bat’s ear is engineered for ultrasonic hearing.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/thomascuypers/49186734333/in/photolist-e5mhwn-2hWsStF-2hWvqig-XMHZf9-XMHZaE-XMHZ8q-qPdXtS">Thomas Cuypers/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>For example, the greater bulldog bat, <em>Noctilio leporinus</em>, can produce <a href="https://doi.org/10.1007/BF00184422">ultrasonic echolocation calls between 30 and 60 kHz</a> when hunting prey and maneuvering during flight. These calls can also get <a href="https://doi.org/10.1371/journal.pone.0002036">incredibly loud – above 140 dB SPL</a>.</p>
<p>Many other small mammals, including other bats, and even some primates such as tiny tarsiers, produce <a href="https://doi.org/10.1098/rsbl.2011.1149">loud ultrasonic sounds humans can’t perceive</a>. In part, these sounds can reach such volumes because their acoustic power is concentrated in a pure tone or single frequency. </p>
<h2>Creating speakers</h2>
<p>Insects are some of the smallest animals to produce loud sounds, chief among them the cicadas and the orthopterans, which include katydids, grasshoppers and crickets. </p>
<p>In North America, the robust conehead, <em>Neoconocephalus robustus</em>, a type of katydid, <a href="https://doi.org/10.1016/0022-1910(77)90127-5">regularly surpasses 105 dB SPL</a>. These calls are produced to attract mates and, like many such calls, are competing against a clamor of comparable sounds from similar species. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/506436/original/file-20230125-16-uec92.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up photo of an insect on a leaf with a hole chewed into it roughly the size of the insect's wings." src="https://images.theconversation.com/files/506436/original/file-20230125-16-uec92.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/506436/original/file-20230125-16-uec92.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=391&fit=crop&dpr=1 600w, https://images.theconversation.com/files/506436/original/file-20230125-16-uec92.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=391&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/506436/original/file-20230125-16-uec92.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=391&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/506436/original/file-20230125-16-uec92.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=491&fit=crop&dpr=1 754w, https://images.theconversation.com/files/506436/original/file-20230125-16-uec92.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=491&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/506436/original/file-20230125-16-uec92.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=491&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A two-spotted tree cricket, <em>Neoxabea bipunctata</em>, chews a hole just the right size for its fore wings. It then ‘sings’ by poking the wings through the hole and rubbing them together.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/pcoin/4027378063">Patrick Coin/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<p>Some insects go one step further, amplifying their sounds by building the functional equivalent of audio speakers. Some tree crickets chew holes in leaves, place their vibrating wings in the opening and <a href="https://doi.org/10.1038/255142a0">use the surrounding leaf as a baffle</a> to prevent the loss of sound energy around the edges of their wings. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/506457/original/file-20230125-24-w5uxcx.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Drawing depicting twin burrows joining below ground in a chamber inhabited by a cricket." src="https://images.theconversation.com/files/506457/original/file-20230125-24-w5uxcx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/506457/original/file-20230125-24-w5uxcx.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=510&fit=crop&dpr=1 600w, https://images.theconversation.com/files/506457/original/file-20230125-24-w5uxcx.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=510&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/506457/original/file-20230125-24-w5uxcx.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=510&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/506457/original/file-20230125-24-w5uxcx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=641&fit=crop&dpr=1 754w, https://images.theconversation.com/files/506457/original/file-20230125-24-w5uxcx.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=641&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/506457/original/file-20230125-24-w5uxcx.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=641&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The male mole cricket sings from his specially designed burrow, which amplifies sound like a horn.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Mole_cricket#/media/File:Mole_cricket_burrow.png">Ian Alexander, new drawing based on Bennet-Clark, 1970 with public domain insect from Lydekker 1879</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Mole crickets, <em>Gryllotalpa vineae</em>, go even further by <a href="https://doi.org/10.1080/09524622.1996.9753321">constructing a burrow that acts like a wind instrument</a>, creating a cavity of vibrating air that amplifies the sound energy they produce. <a href="https://doi.org/10.1242/jeb.128.1.383">These crickets’ songs can travel almost half a mile</a> (0.8 kilometer).</p>
<h2>Irksome invaders</h2>
<p>The <a href="https://welcome.topuertorico.org/coqui.shtml">official mascot of Puerto Rico</a> is a 1-to-2-inch (2-5-centimeter) frog called the coquí, <em>Eleutherodactylus coqui</em>, whose call is a combination of two pure tones – “ko” and “kee,” from which it gets its name. At 114-120 dB SPL, the frog’s calls are so loud they actually must <a href="https://doi.org/10.1121/1.402844">protect their own hearing when vocalizing</a>, by increasing the air pressure inside their middle ear.</p>
<p>Unfortunately, in the past few decades humans have accidentally <a href="https://www.pbs.org/newshour/science/grab-earplugs-invasive-coqui-frogs-gain-foothold-california">introduced the coquí</a> to a number of areas outside their native range, in particular the Hawaiian islands, <a href="https://www.oahuisc.org/coqui-frog/">where they have no natural predators</a> and <a href="https://www.biisc.org/pest/coqui/">have become invasive pests</a>. Since coquí calls are within an octave of humans’ best hearing – and they’re nocturnal – many Hawaiians suffer <a href="https://www.nps.gov/articles/coqui.htm">sleep disruptions because of the tiny frogs</a>.</p>
<p>So even if you’re small, it’s not impossible to make yourself heard. You just have to blast all your acoustic energy in a single frequency, and hit the sweet spot of your audience’s hearing.</p><img src="https://counter.theconversation.com/content/192810/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bernard Lohr has received funding from the National Institute on Deafness and Other Communication Disorders and the U. S. Fish and Wildlife Service. </span></em></p>From insects to birds to bats to frogs, these little loudmouths have found ingenious ways to deliver their messages at high volume.Bernard Lohr, Associate Professor of Biological Sciences, University of Maryland, Baltimore CountyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1969662023-01-27T11:59:40Z2023-01-27T11:59:40ZEarwax removal no longer available at GP surgeries – leaving many struggling to hear<figure><img src="https://images.theconversation.com/files/506314/original/file-20230125-24-dh3ts5.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6497%2C4325&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/horizontal-shot-frustrated-young-caucasian-female-1950619960">Anatoliy Karlyuk/Shutterstock</a></span></figcaption></figure><p>Each year, more than <a href="https://doi.org/10.1093/qjmed/hch082">2 million people in the UK</a> have troublesome earwax that needs to be removed. However, more people are finding that this service is no longer being provided at their GP surgery. In fact, 66% of people seeking these services have been told that earwax removal is <a href="https://rnid.org.uk/wp-content/uploads/2022/11/Ear-Wax-Report-FINAL.pdf">no longer available on the NHS</a>.</p>
<p><a href="https://questions-statements.parliament.uk/written-questions/detail/2020-09-15/90063">Questions have been raised in parliament</a> about why people are being referred to earwax clinics in hospitals. This results in long waiting times and is not the best use of specialist services. </p>
<p>Many people are resorting to using private services on the high street that cost around £50 to £100. But the Royal National Institute for Deaf People (RNID), a charity, reports that more than a quarter of people they surveyed <a href="https://rnid.org.uk/wp-content/uploads/2022/11/Ear-Wax-Report-FINAL.pdf">cannot afford to pay</a> to have their earwax removed privately. This especially applies to people requiring recurrent earwax removal, such as those who wear hearing aids and earbud earphones – which tend to cause impacted earwax.</p>
<p>Our bodies produce earwax to clean, protect and keep our ears healthy. Movement of the jaw, as well as the skin that lines the ear canal, causes the wax to move to the entrance of the ear where it then flakes off or is carried away when we wash. Sometimes this doesn’t work and the earwax becomes impacted. Impacted earwax that blocks the ear canal is a major reason for GP consultations.</p>
<p>The National Institute for Health and Care Excellence (Nice) is clear that NHS earwax removal <a href="https://www.nice.org.uk/guidance/ng98/chapter/Recommendations#removing-earwax">services should be provided in the community</a> where demand is greatest. Why is this recommendation for community earwax removal services falling on deaf ears? </p>
<p>A recommendation from Nice is not a mandate, and GPs are under no obligation to offer an earwax removal service. There are several reasons this service is often no longer offered in primary care, some of which are based on misunderstandings.</p>
<p>First, manual water-filled syringes for flushing out earwax can cause high pressure of water and might damage the patient’s ears – not something a GP wants to be responsible for doing. (Alternative cheap, low-pressure water irrigation devices are now widely available.) </p>
<p>Second, there is a mistaken belief among some GPs that earwax can be self-managed using wax-softening ear drops on their own. However, there is <a href="https://www.nice.org.uk/guidance/ng98">no good quality evidence</a> that softened earwax dissolves and magically disappears into the ether.</p>
<h2>Effects of impacted earwax</h2>
<p>The <a href="https://bjgp.org/content/73/727/90">most common symptom</a> caused by impacted earwax is hearing difficulty. This is often accompanied by discomfort and noises in the ears. <a href="https://healthwatchoxfordshire.co.uk/summarised-reports/getting-treatment-for-earwax-and-hearing-problems-in-oxfordshire/">Healthwatch Oxfordshire</a>, a charity, revealed that adults with earwax required between one and four NHS visits before attending a dewaxing clinic and that the time from first experiencing symptoms to final resolution was three to 30 weeks. </p>
<p>Try simulating the effect of impacted wax by walking around with your fingers firmly plugging both of your ears for a few days. You’ll soon realise that what at first sounds trivial is no laughing matter.</p>
<p>Hearing difficulty means you can’t communicate with ease or listen to the TV. It also reduces your ability to detect and monitor sounds in the environment, such as an approaching car. Hearing difficulty can lead to <a href="https://www.nice.org.uk/guidance/ng98">social isolation and depression</a>. More than <a href="https://doi.org/10.3399/bjgp23X732009">nine out of ten people</a> report that impacted earwax was at least moderately bothersome to them, and 60% said it is very or extremely bothersome.</p>
<p><a href="https://www.nice.org.uk/guidance/ng98/chapter/Recommendations#removing-earwax">Nice recommends</a> that impacted earwax is removed by irrigating the ear with the newer, safer low-pressure water irrigation devices, or microsuction to hoover it up. When questioned, most people <a href="https://doi.org/10.3399/bjgp23X732009">do not have a preference</a>, although some report that water irrigation is messy and others that microsuction causes discomfort and is noisy.</p>
<p>Removal of earwax in health centres using microsuction results in levels of <a href="https://doi.org/10.3399/bjgpopen19X101649">patient satisfaction</a> that are at least as good as those provided in a hospital.</p>
<p>Before removal, pre-treatment drops or sprays are used to soften the earwax. These are applied daily for up to five days before removal. There is a vast array of pre-treatment earwax softening products, but <a href="https://www.nice.org.uk/guidance/ng98/chapter/Recommendations#removing-earwax">none are better than any other</a>. As a result, most people use olive oil, which can be administered as drops or as a spray.</p>
<p>There are a variety of self-administered, earwax management products on the market but the evidence for these is limited and <a href="https://www.nice.org.uk/guidance/ng98/chapter/Recommendations#removing-earwax">none are currently recommended by Nice</a>. An example is the use of Hopi ear candles or cones. To use these, you lie with your head on one side and place the lit candle in the upward-facing ear. </p>
<p>These are reported to work by softening the wax and then sucking it out of the ear canal and up the cone like a chimney. There is <a href="https://aao-hnsfjournals.onlinelibrary.wiley.com/doi/10.1177/0194599816671491">no evidence</a> to support this claim. These candles and cones cost money and are ineffective.</p>
<figure class="align-center ">
<img alt="The author, Kevin Munro, trying Hopi ear candles." src="https://images.theconversation.com/files/506534/original/file-20230126-22936-u4nv53.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/506534/original/file-20230126-22936-u4nv53.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/506534/original/file-20230126-22936-u4nv53.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/506534/original/file-20230126-22936-u4nv53.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/506534/original/file-20230126-22936-u4nv53.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/506534/original/file-20230126-22936-u4nv53.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/506534/original/file-20230126-22936-u4nv53.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The author, Kevin Munro, tries Hopi ear candles.</span>
<span class="attribution"><span class="source">Kevin Munro</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>How it could be done</h2>
<p>If individual GP surgeries lack the expertise or funding to provide earwax removal services, an alternative is for groups of practices to collaborate as a network. The portable nature of modern wax removal equipment is ideal in such settings and for use in home visits. This approach could be especially valuable for vulnerable people, such as those in care homes where <a href="https://doi.org/10.1016/j.jamda.2022.07.011">44% of residents with dementia also have impacted earwax</a>.</p>
<p>In the meantime, the withdrawal of NHS earwax removal services is having a <a href="https://rnid.org.uk/wp-content/uploads/2022/11/Ear-Wax-Report-FINAL.pdf">far-reaching impact</a>, with people experiencing bothersome and distressing symptoms, sometimes leading to poor mental health.</p><img src="https://counter.theconversation.com/content/196966/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kevin Munro does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Impacted earwax that blocks the ear canal is a major reason for GP consultations.Kevin Munro, Ewing Professor of Audiology, University of ManchesterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1960972023-01-23T13:24:48Z2023-01-23T13:24:48ZCochlear implants can bring the experience of sound to those with hearing loss, but results may vary – here’s why<figure><img src="https://images.theconversation.com/files/504991/original/file-20230117-14-1zs337.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2121%2C1412&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A patient's age upon receiving a cochlear implant can influence the technology's effectiveness.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/yr-old-boy-with-cochlear-implant-studying-and-royalty-free-image/1203208092">Cavan Images/Cavan via Getty Images</a></span></figcaption></figure><p>Cochlear implants are among the most successful neural prostheses on the market. These artificial ears have allowed nearly <a href="https://doi.org/10.1121/10.0012825">1 million people globally</a> with severe to profound hearing loss to either regain access to the sounds around them or experience the sense of hearing for the first time.</p>
<p>However, the effectiveness of cochlear implants varies greatly across users because of a <a href="https://doi.org/10.1097%2FAUD.0b013e3182741aa7">range of factors</a>, such as hearing loss duration and age at implantation. Children who receive implants at a <a href="https://doi.org/10.1001/archotol.130.5.570">younger age may</a> may be able to acquire auditory skills similar to their peers with natural hearing.</p>
<p>I am a <a href="https://search.asu.edu/profile/3630640">researcher studying pitch perception with cochlear implants</a>. Understanding the mechanics of this technology and its limitations can help lead to potential new developments and improvements in the future.</p>
<h2>How does a cochlear implant work?</h2>
<p>In <a href="https://www.nidcd.nih.gov/health/how-do-we-hear">fully-functional hearing</a>, sound waves enter the ear canal and are converted into neural impulses as they move through hairlike sensory cells in the cochlea, or inner ear. These neural signals then travel through the auditory nerve behind the cochlea to the central auditory areas of the brain, resulting in a perception of sound.</p>
<p>People with severe to profound hearing loss often have damaged or missing sensory cells and are unable to convert sound waves into electrical signals. Cochlear implants bypass these hairlike cells by <a href="https://doi.org/10.1016/j.heares.2008.06.005">directly stimulating the auditory nerve</a> with electrical pulses.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/505008/original/file-20230117-20-hub8am.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagram of anatomy of hearing" src="https://images.theconversation.com/files/505008/original/file-20230117-20-hub8am.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/505008/original/file-20230117-20-hub8am.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=538&fit=crop&dpr=1 600w, https://images.theconversation.com/files/505008/original/file-20230117-20-hub8am.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=538&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/505008/original/file-20230117-20-hub8am.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=538&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/505008/original/file-20230117-20-hub8am.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=676&fit=crop&dpr=1 754w, https://images.theconversation.com/files/505008/original/file-20230117-20-hub8am.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=676&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/505008/original/file-20230117-20-hub8am.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=676&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sound travels through the ear canal and is converted by hair cells in the cochlea into electrical signals that enter the brain.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/hearing-cross-section-of-humans-ear-with-royalty-free-illustration/1345828402">ttsz/iStock via Getty Images Plus</a></span>
</figcaption>
</figure>
<p>Cochlear implants consist of an external part wrapped behind the ear and an internal part implanted under the skin. </p>
<p>The external unit, which includes a microphone, signal processor and transmitter, picks up and processes sound waves from the environment. It divides sounds into different frequency bands, which are like different channels on a radio, with each band representing a specific range of frequencies within an overall spectrum of sound. It also extracts information about amplitude, or loudness, from each frequency band.</p>
<p>It then transmits that information to the receiver in the internal unit implanted in the cochlea. The electrodes of the internal unit directly stimulate the auditory nerve with electrical pulses based on amplitude information. Electrodes at the base of the cochlea transmit electrical signals containing high-frequency auditory information while electrodes at the top transmit electrical signals containing low-frequency information to the brain, mimicking the frequency analysis in a fully-functioning ear.</p>
<h2>Where cochlear implants fall short</h2>
<p>While people with cochlear implants are able to detect sounds and perceive speech in quiet environments reasonably well, they often have great difficulty <a href="https://doi.org/10.1016/j.heares.2008.06.005">understanding speech in noisy environments</a>, <a href="https://doi.org/10.1177/108471380400800203">enjoying music</a> and <a href="https://doi.org/10.1121/1.2821965">localizing sounds</a>, that is, figuring out which direction a sound is coming from.</p>
<p>Cochlear implants are <a href="https://doi.org/10.1044/2020_JSLHR-19-00225">fundamentally limited</a> by their poor ability to tell the difference between sound frequencies and transmit rapid variations in sound amplitude over time. For example, current cochlear implant systems use only 12 to 22 electrodes to stimulate surviving auditory nerve fibers, whereas natural hearing has 30,000 auditory nerve fibers to encode detailed information about incoming sounds. Furthermore, electrode stimulation inside the cochlea excites a large group of auditory nerve fibers without much precision. </p>
<p>These factors result in poor frequency resolution. Picture it like painting with a thick brush that can show only an overall shape without the fine details, or only blurry details.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/xW4qfOkA4oc?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The hearing experience from cochlear implants differs from that of natural hearing.</span></figcaption>
</figure>
<h2>Why cochlear implants work better for some</h2>
<p>It remains <a href="https://doi.org/10.1371/journal.pone.0048739%E2%80%8B">difficult to accurately predict</a> the performance of cochlear implants for each user. </p>
<p>There are <a href="https://doi.org/10.1177/000348949810701102">a variety of factors</a> that can affect the number of healthy auditory nerve fibers available to transmit acoustic information to the brain. Cochlear implant users with better survival of their auditory nerve fibers may have improved <a href="https://doi.org/10.1016/j.heares.2014.09.009">frequency and timing representations of sounds</a> represented by electrical stimulation, which can lead to better speech and pitch perception.</p>
<p>Neural health is not the only factor that contributes to variability in cochlear implant effectiveness. One 2012 study of 2,251 cochlear implant users found that <a href="https://doi.org/10.1371/journal.pone.0048739">speech recognition varied greatly</a>, and only 22% of the difference could be explained by clinical factors like length of experience with the implant and cause of hearing loss. Furthermore, it is <a href="https://doi.org/10.1007/s10162-022-00876-w">challenging to directly assess</a> the effects of neural survival on the performance of cochlear implants. This suggests that other factors also play a role in determining the success of speech recognition with cochlear implants.</p>
<p>For instance, research has found that <a href="https://doi.org/10.1097/MAO.0000000000002544">cognitive skills</a> like working memory can influence the extent to which a person can understand speech after implantation. Cochlear implants <a href="https://doi.org/10.1097/AUD.0000000000000145">increase cognitive load</a>, or the amount of mental effort required to perform a task, as the sound quality users hear is often lower than that of natural hearing. Aging may also negatively affect cognitive processing skills, including <a href="https://doi.org/10.1097/AUD.0b013e3182741aa7">attention deficits and slower processing speed</a> on listening tasks.</p>
<p>Furthermore, most of the implant’s electrode arrays don’t reach the top of the cochlea where low-frequency information is conveyed in natural hearing. This <a href="https://doi.org/10.1097%2FAUD.0000000000000163">leads to mismatches</a> between the frequencies conveyed by the implant and those of natural hearing, resulting in reduced sound quality.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/504988/original/file-20230117-11104-w83z6d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Four cochlear implants of different colors." src="https://images.theconversation.com/files/504988/original/file-20230117-11104-w83z6d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/504988/original/file-20230117-11104-w83z6d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=512&fit=crop&dpr=1 600w, https://images.theconversation.com/files/504988/original/file-20230117-11104-w83z6d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=512&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/504988/original/file-20230117-11104-w83z6d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=512&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/504988/original/file-20230117-11104-w83z6d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=644&fit=crop&dpr=1 754w, https://images.theconversation.com/files/504988/original/file-20230117-11104-w83z6d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=644&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/504988/original/file-20230117-11104-w83z6d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=644&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The effectiveness of cochlear implants varies based on a number of factors.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/cohlear-implant-devices-royalty-free-image/490611153">Elizabeth Hoffmann/iStock via Getty Images Plus</a></span>
</figcaption>
</figure>
<h2>Improving cochlear implants</h2>
<p>Scientists are investigating a number of potential ways to improve the effectiveness of cochlear implants.</p>
<p>Hearing sound through electrical stimulation is a new experience for those used to hearing without an implant. Auditory training exercises can help familiarize users with this new form of hearing and <a href="https://doi.org/10.1177/1084713807301379">may even enhance overall speech and music perception</a>. However, even with training, conventional cochlear implants may not fully replicate the rich experience of natural hearing.</p>
<p>Researchers are studying the potential <a href="https://spectrum.ieee.org/cochlear-implant">use of light beams</a> instead of electrical pulses to obtain better frequency resolution. This is done by genetically modifying the auditory nerve fibers to make them sensitive to light. Because light beams are able to more selectively stimulate auditory neurons compared to electrical pulses, this tactic may result in more precise frequency information. The research team behind this approach aims to start clinical trails in 2026.</p>
<p>Another approach involves <a href="https://twin-cities.umn.edu/news-events/university-minnesota-lead-97-million-nih-grant-improve-hearing-restoration">inserting electrodes directly into auditory nerve fibers</a> instead of the cochlea. By increasing the number of available electrodes, this strategy may enhance the sound frequency and timing information of the implant, and improve speech understanding in noisy environments and music perception.</p>
<p>Lastly, another development uses <a href="https://doi.org/10.7554/eLife.76682">magnetic stimulation</a> to transmit acoustic information via small, implantable microcoils. This approach allows for finer stimulation patterns than the widespread electrical activation of traditional electrodes, potentially leading to more precise sounds representation.</p>
<p>Research on new technologies may provide solutions to further improve the hearing experience for those struggling with hearing loss.</p><img src="https://counter.theconversation.com/content/196097/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Niyazi Arslan receives educational funding from the Republic of Türkiye.</span></em></p>Researchers are exploring different ways to improve how cochlear implant users perceive speech and music in noisy environments.Niyazi Arslan, Ph.D. Candidate in Speech and Hearing Science, Arizona State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1929362022-11-04T12:34:56Z2022-11-04T12:34:56ZOver-the-counter hearing aids offer a wide range of options – here are things to consider before buying<figure><img src="https://images.theconversation.com/files/493199/original/file-20221103-18-v5rzin.jpg?ixlib=rb-1.1.0&rect=51%2C8%2C5760%2C3785&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Now that over-the-counter hearing aids are available, it's important to know what questions to ask.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/hearing-impaired-mature-man-adjusts-settings-for-royalty-free-image/1364368694?phrase=hearing%2Baids">peakSTOCK/iStock via Getty Images Plus</a></span></figcaption></figure><p>Following the <a href="https://www.fda.gov/news-events/press-announcements/fda-finalizes-historic-rule-enabling-access-over-counter-hearing-aids-millions-americans">U.S. Food and Drug Administration’s ruling</a> in August 2022, nonprescription over-the-counter hearing aids went on sale <a href="https://www.cnbc.com/2022/10/17/hearing-aids-are-now-available-over-the-counter-from-walgreens-cvs-and-best-buy.html">at pharmacies, supermarkets and consumer electronic stores</a> on Oct. 17, 2022. These devices are intended only for people with perceived mild to moderate hearing loss.</p>
<p>For millions of Americans, these over-the-counter hearing aids are <a href="https://www.nidcd.nih.gov/health/over-counter-hearing-aids">easier to access and less expensive</a> than prescription versions. Some people view them as a <a href="https://www.nytimes.com/wirecutter/blog/over-the-counter-hearing-aids/">tremendous innovation</a>. Yet others say <a href="https://thehill.com/blogs/pundits-blog/healthcare/333943-sen-warrens-not-listening-otc-hearing-aids-will-do-more-harm-than-good/">they won’t work optimally</a>, as the device may be of poor quality, or consumers may not self-diagnose or customize the device appropriately. </p>
<p>As <a href="https://som.ucdenver.edu/Profiles/Faculty/Profile/36711">audiologists specializing</a> in <a href="https://www.uchealth.org/provider/cory-portnuff/">hearing care</a>, we are actively involved in <a href="https://scholar.google.at/citations?user=rgECg40AAAAJ&hl=en">health care research</a> and the <a href="https://scholar.google.com/citations?user=JdYxmRoAAAAJ&hl=en">clinical care</a> of people with a range of hearing disorders. We have also conducted research on <a href="https://virtualhearinglab.org/">over-the-counter hearing aids</a>. </p>
<p>Our aim is to present a balanced view on what is known about over-the-counter aids based on academic research – and provide you tips on what to know when shopping for these devices. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/WgUdp_LgVBQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The U.S. Food and Drug Administration estimates that 30 million Americans could benefit from hearing aids.</span></figcaption>
</figure>
<h2>Hearing device categories</h2>
<p>The newly available <a href="https://www.federalregister.gov/documents/2022/08/17/2022-17230/medical-devices-ear-nose-and-throat-devices-establishing-over-the-counter-hearing-aids">over-the-counter hearing aids</a> add to a range of existing devices, including <a href="https://www.fda.gov/medical-devices/guidance-documents-medical-devices-and-radiation-emitting-products/class-ii-special-controls-guidance-document-transcutaneous-air-conduction-hearing-aid-system-tachas">conventional prescription hearing aids</a> and <a href="https://www.federalregister.gov/documents/2019/10/28/2019-23464/medical-devices-ear-nose-and-throat-devices-classification-of-the-self-fitting-air-conduction">self-fitting hearing devices</a>. Conventional hearing aids are tailored to fit by a hearing care professional. But over-the-counter devices come either in self-fitting types – meaning they adjust to the wearer’s hearing after self-testing – or preset, a type that is less individualized.</p>
<p>In addition, there are three other categories of hearing-related devices to be aware of. These include <a href="https://www.fda.gov/consumers/consumer-updates/hearing-aids-and-personal-sound-amplification-products-what-know">personal sound amplification products</a>, which serve as hearing enhancement devices for individuals with normal hearing. A second type are called <a href="https://www.hearingtracker.com/hearables">hearables</a>, like wireless earbuds designed for listening to music or tracking fitness. The third fall under consumer audio, like headphones. </p>
<p>None of the products in those categories are regulated, because they are not considered medical devices. But as technology advances, many of them may have functions similar to hearing aids. In other words, all the hearing devices listed above may look similar to one another and may be hard to distinguish just by their appearance. </p>
<p>Because of the variety of devices on the market, you should read product labels to make sure you’re not confusing over-the-counter hearing aids with other technologies. It is not uncommon to see <a href="https://www.ftc.gov/news-events/news/press-releases/1995/11/ftc-settles-false-advertising-charges-against-maker-miracle-ear">false advertising claims</a>, such as personal sound amplification products or hearables advertised as over-the-counter hearing aids. </p>
<h2>About over-the-counter aids</h2>
<p>As noted, over-the-counter hearing aids come in two types: one-size-fits-most, with preset listening programs, and self-fitting, which can be more finely adjusted using apps on a smartphone. The latter type goes through a more rigorous <a href="https://www.fda.gov/medical-devices/device-approvals-denials-and-clearances/510k-clearances">government approval process</a> and generally costs more. The least expensive ones cost around US$200, with the most running about $800. For comparison, prescription hearing aids start at roughly $1,000 and go up to approximately $6,000 per pair. The difference in cost is based on the technology level of the device as well as added services provided by hearing care professionals. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/492395/original/file-20221029-53244-cubwfz.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Flow chart diagram showing the varying types of hearing aid options." src="https://images.theconversation.com/files/492395/original/file-20221029-53244-cubwfz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/492395/original/file-20221029-53244-cubwfz.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=205&fit=crop&dpr=1 600w, https://images.theconversation.com/files/492395/original/file-20221029-53244-cubwfz.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=205&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/492395/original/file-20221029-53244-cubwfz.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=205&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/492395/original/file-20221029-53244-cubwfz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=258&fit=crop&dpr=1 754w, https://images.theconversation.com/files/492395/original/file-20221029-53244-cubwfz.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=258&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/492395/original/file-20221029-53244-cubwfz.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=258&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The cost of hearing devices varies dramatically, depending on their features and sophistication.</span>
<span class="attribution"><span class="source">Vinaya Manchaiah, University of Colorado School of Medicine</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p><a href="https://doi.org/10.2147/CIA.S135390">Our review of the literature</a> on over-the counter aids revealed the following: First, several studies looking at their acoustic characteristics – that is, the degree of sound distortion and self-generated noise – found mixed results. Some over-the-counter hearing products <a href="https://doi.org/10.1155/2015/827463">don’t measure up to acceptable standards</a>, whereas others <a href="https://doi.org/10.1097/MAO.0000000000001414">do provide appropriate amplification</a>. </p>
<p>Second, several <a href="https://hearingreview.com/hearing-products/marketrak-viii-utilization-of-psaps-and-direct-mail-hearing-aids-by-people-with-hearing-impairment">large-scale consumer surveys in the U.S.</a> and <a href="https://www.ehima.com/surveys/">Japan</a> suggest that users are less satisfied with over-the-counter aids than with conventional prescription hearing aids. This lower satisfaction can be primarily attributed to consumers choosing inappropriate devices or being unable to personalize or handle them.</p>
<p>Conversely, several clinical trials <a href="https://doi.org/10.1177/2331216519900589">measuring the self-fitting process</a> and the benifits of over-the-counter hearing aids <a href="https://doi.org/10.1044/2017_AJA-16-0111">generally report positive outcomes</a> for people with mild to moderate hearing loss. More <a href="https://clinicaltrials.gov/ct2/results?cond=Hearing+Loss%2C+Sensorineural&term=OTC+hearing+aid&cntry=&state=&city=&dist=">clinical trials are ongoing</a>. </p>
<p>To add to the confusion, there is another caveat to those studies: Most examined early generations of direct-to-consumer hearing devices such as the personal sound amplification products – not the over-the-counter hearing aids that are now on the market. That is why consumers should take the results of those early studies with some skepticism. What’s more, as the market matures, a combination of competition and regulation will likely improve the quality of the devices.</p>
<h2>Questions to consider before purchasing</h2>
<p>You’ll want to take into account the look, feel and capabilities of the device. Ask yourself: Do you want a hearing aid that looks more like a wireless earbud – small and not noticeable? Is it comfortable to wear or irritating after several hours? Will it work with a smartphone and Bluetooth? How often does it need to be recharged?</p>
<p>Also: What is the warranty? How can I get the device fixed if it breaks? What’s the return policy? Is there free customer support after the purchase? Is the device appropriate for my particular kind of hearing issue?</p>
<p>Only a <a href="https://www.usatoday.com/story/money/reviewed/2022/10/17/otc-hearing-aids-buy-now-bose-lively/10523887002/">handful of companies</a> now offer over-the-counter hearing aids. Some may not be in the business for very long. So choose a brand with a good reputation that stands behind its product, offers customer service assistance and lets you return the device and receive a refund if it doesn’t work for you.</p>
<p>Studies show that people often <a href="https://doi.org/10.1001/jamanetworkopen.2020.15009">underestimate the severity of their hearing loss</a>. For these people, the over-the-counter devices may not provide adequate amplification. Remember, they work only for those with mild to moderate hearing loss. In addition, some people may have treatable hearing problems, like earwax buildup, that need medical treatment instead of hearing aids. </p>
<p>That’s why we strongly recommend consumers get a hearing test from an audiologist before purchasing the over-the-counter hearing aids. If that is not feasible, you can take a <a href="https://www.who.int/teams/noncommunicable-diseases/sensory-functions-disability-and-rehabilitation/hearwho">free online hearing test</a> and also <a href="https://sites.northwestern.edu/cedra/">screen yourself for risk of an ear disease</a> or other conditions that may affect hearing. And <a href="https://doi.org/10.1044/2018_JSLHR-H-18-0370">online consumer reviews</a> provide user reports on the perceived benefits and limitations about specific products. </p>
<p>If you find the over-the-counter devices don’t work for you, there may be <a href="https://www.hearingloss.org/hearing-help/technology/otc-hearing-devices/otc-hearing-aids/">some issues that are fixable</a>. But if not, don’t forget: You always have the option to return them – and then, make an appointment with <a href="https://theconversation.com/newly-available-over-the-counter-hearing-aids-offer-many-benefits-but-consumers-should-be-aware-of-the-potential-drawbacks-189041">a hearing health care professional</a>.</p><img src="https://counter.theconversation.com/content/192936/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>They are cheaper to buy and don’t require a doctor’s prescription. But OTC hearing aids come with some limitations.Vinaya Manchaiah, Professor of Otolaryngology – Head & Neck Surgery , University of Colorado Anschutz Medical CampusCory Portnuff, Assistant Clinical Professor of Audiology, Clinical Audiologist, University of Colorado Anschutz Medical CampusLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1890412022-10-21T12:38:54Z2022-10-21T12:38:54ZNewly available over-the-counter hearing aids offer many benefits, but consumers should be aware of the potential drawbacks<figure><img src="https://images.theconversation.com/files/490440/original/file-20221018-7297-l8bqgl.jpg?ixlib=rb-1.1.0&rect=8%2C8%2C5583%2C3713&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Over-the-counter hearing aids are now available at pharmacies and big-box stores.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/senior-woman-holding-hearing-aid-close-up-royalty-free-image/926841484?phrase=hearing%20aids&adppopup=true">Mara Ohlsson/Image Source via Getty Images</a></span></figcaption></figure><p>U.S. retailers <a href="https://www.usatoday.com/story/news/health/2022/10/17/over-the-counter-hearing-aids-available/10522017002/">began selling over-the-counter hearing aids</a> on Oct. 17, 2022, a long-awaited move that some experts predict could be a game-changer in <a href="https://www.pbs.org/newshour/health/you-can-now-buy-lower-cost-hearing-aids-over-the-counter-heres-how">making these devices accessible and affordable</a>. A prescription is no longer needed, nor is a visit to a doctor or even a fitting appointment with a hearing specialist. </p>
<p>Instead, Americans <a href="https://www.cnn.com/2022/10/17/health/over-the-counter-hearing-aids-available/index.html">can purchase hearing aids</a> by going online or with a single trip to the nearest pharmacy or big-box store. These aids are only for those with mild to moderate hearing loss. For these consumers, over-the-counter hearing aids clearly offer an appealing alternative. </p>
<p><a href="https://med.virginia.edu/otolaryngology/faculty/bradley-w-kesser-m-d/">As an otologist/neurotologist</a> – that’s someone who specializes in the diseases of the ear – I like to say that while vision binds us to the world, hearing binds us to each other. In my practice, I see firsthand how patients with hearing loss often withdraw socially and become isolated. They don’t want to put themselves in situations where they may mishear or seem disengaged, disinterested or unintelligent. This may be why studies show hearing loss is <a href="https://doi.org/10.1097/MOO.0000000000000825">associated with depression</a> and <a href="https://doi.org/10.1093/geronb/gbab194">cognitive impairment</a>. </p>
<p>So it seems the over-the-counter hearing aids would be a great solution for patients with hearing loss, right? Less hassle and less cost – in many cases, thousands of dollars less – and more people than ever getting the help they need. But it’s not that simple. Occurring just two months after the U.S. Food and Drug Administration’s <a href="https://www.fda.gov/news-events/press-announcements/fda-finalizes-historic-rule-enabling-access-over-counter-hearing-aids-millions-americans">final ruling on the matter</a>, over-the-counter sales of hearing aids come with caveats and even some risks.</p>
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<figcaption><span class="caption">Prior to the availability of over-the-counter devices, only 30% of those over age 70 with hearing loss used hearing aids.</span></figcaption>
</figure>
<h2>How hearing loss happens</h2>
<p>Hearing specialists divide hearing loss into two main categories: <a href="https://www.asha.org/public/hearing/conductive-hearing-loss/#:">conductive</a> and <a href="https://www.asha.org/public/hearing/sensorineural-hearing-loss/">sensorineural hearing loss</a>. Conductive loss is caused by any number of things, including ear wax obstruction, a perforation in the ear drum or fluid in the middle ear. Children are more likely than adults to have conductive hearing loss, and most of the time, many of these problems are relatively easy to correct. </p>
<p>But sensorineural hearing loss is caused by a problem occurring in the inner ear, auditory nerve and brain. Most commonly, there is a loss of the tiny cochlear hair cells that <a href="http://www.cochlea.eu/en/hair-cells">convert sounds into an electrical signal</a>. The brain interprets that signal as a bird singing or a child laughing. Hair cell injury is generally permanent and irreversible; those cells do not regenerate in humans, or for that matter, in any mammal. </p>
<p>Whether conductive or sensorineural, hearing aids have proved to be a tremendous boon for patients with hearing loss. One national survey found that in 2019, 7.1% of adults aged 45 and over <a href="https://www.cdc.gov/nchs/products/databriefs/db414.htm">used a hearing aid</a>. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/x4PGyDjuahI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Over-the-counter hearing aids are not for everyone who has hearing loss.</span></figcaption>
</figure>
<h2>Problems with over-the-counter hearing aids</h2>
<p>Before over-the-counter hearing aids became available, patients <a href="https://www.nidcd.nih.gov/health/do-you-need-hearing-test">needed a formal hearing test and assessment</a>. This is critical because not all hearing loss is the same; hearing specialists – both otolaryngologists and audiologists – are trained to decipher the type of hearing loss that a patient is experiencing. From that, they make recommendations on hearing treatment. If a patient needs a hearing aid, a health care professional will <a href="https://www.healthyhearing.com/help/hearing-aids/fitting">fit them with one</a>.</p>
<p>But purchasing an over-the-counter hearing aid requires none of those things – not an ear exam, not a hearing test and not a fitting session. There are many reasons why this shortcut approach, while certainly less expensive and offering easier access, may not be ideal for someone experiencing hearing loss.</p>
<p>First, patients may have a chronic infection or condition that requires medical or surgical management, rather than a hearing aid. Second, some patients may be a candidate for surgical correction of their hearing loss. Third, patients with hearing loss in one ear or a large difference in hearing between the two ears may have a benign growth on the hearing and balance nerve. This often requires surgery or radiation treatment. Again, a hearing aid would not help with this condition. </p>
<p>Additionally, for those who would benefit from an over-the-counter product, not every hearing aid fits every ear – one size most certainly does not fit all. And one more caveat: Over-the-counter hearing aids are not recommended for people under 18. </p>
<p>Finally, some patients may have too much hearing loss for these devices to provide any benefit. Instead, many patients with more advanced hearing loss have <a href="https://www.nidcd.nih.gov/health/cochlear-implants">the option of a cochlear implant</a>, which is essentially a wire with an electrode array surgically placed into the cochlea, the bony “house” of the hair cells situated deep in the skull. The electrodes stimulate the auditory nerve directly, bypassing the damaged hair cells. For these patients, cochlear implants offer <a href="https://www.mayoclinic.org/tests-procedures/cochlear-implants/about/pac-20385021">an exceptional opportunity to hear again</a>. As the technology improves, more people will become candidates for this medical miracle.</p>
<p>About 80% of adults aged 55 to 74 who would benefit from a hearing aid <a href="https://doi.org/10.3109/14992027.2013.769066">do not use them</a>. The new over-the-counter hearing aids hold great promise for the right patients. But buyer beware: They are not panaceas. Not all customers will be satisfied with over-the-counter hearing aids – and a visit to the doctor or audiologist is still critical.</p><img src="https://counter.theconversation.com/content/189041/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bradley Kesser does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>They are easy to get, and far less costly than prescription hearing aids. But over-the-counter devices are not the answer for everyone with hearing issues.Bradley Kesser, Professor of Otology/Neurotology, University of VirginiaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1864082022-08-22T16:58:04Z2022-08-22T16:58:04ZNoise pollution is hurting animals – and we don’t even know how much<figure><img src="https://images.theconversation.com/files/479868/original/file-20220818-349-fpgn2y.jpg?ixlib=rb-1.1.0&rect=0%2C35%2C5991%2C3952&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">If you don't like noise, imagine how pets and other animals feel about it. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/portrait-dog-ears-covered-human-hands-2001561884">Aleksey Boyko/Shutterstock</a></span></figcaption></figure><p>From construction projects to busy roads, aeroplanes and railways, human noise is everywhere. It is an invisible cause of stress, posing <a href="https://ehp.niehs.nih.gov/doi/abs/10.1289/ehp.00108s1123">serious risks to human health and wellbeing</a>. However, noise also harms animals living in close contact with humans, in homes, farms and zoos.</p>
<p>Noise is a distracting, scary or physically painful sound. <a href="https://www.who.int/europe/health-topics/noise#tab=tab_1">The impacts of noise</a> upon humans range from mild irritation to learning and memory problems, permanent hearing damage and heart disease.</p>
<p>Abnormally loud noise, such as at music concerts or construction sites, is <a href="https://www.gov.uk/guidance/noise-nuisances-how-councils-deal-with-complaints">controlled to protect human hearing</a>. But noise is not regulated for other animals.</p>
<p>In our <a href="https://www.frontiersin.org/articles/10.3389/fvets.2022.889117/full">recent paper</a>, we found a greater awareness and more understanding is needed into how noise harms pets, farm and working animals and zoo animals. </p>
<p>Research tends to measure how loud a noise is in decibels (dB). Decibels are easy to measure with a handheld device and form the basis of <a href="https://www.who.int/europe/health-topics/noise#tab=tab_1">human health guidelines</a>. But the type of noise source, frequency (pitch), rate and duration can also impact how noise is experienced by a listener. </p>
<p>Great apes have <a href="https://pubmed.ncbi.nlm.nih.gov/2227723/">similar hearing capabilities</a> to humans, but the rest of the animal kingdom perceives noise very differently. Hearing ranges from very high frequency ultrasound (>20,000 Hz) echolocation in bats and <a href="https://www.researchgate.net/publication/286597329_Hearing_and_Echolocation_in_Dolphins">dolphins</a> to very low frequency infrasound <a href="https://www.utoledo.edu/al/psychology/pdfs/comphearaudio/Hearing_in_the_Elephant_Elephas_maximus_SC1980.pdf">(<20 Hz) in elephants</a>. The hearing range of humans sits right between ultra and infrasound. </p>
<p>Some invertebrates such as <a href="https://www.nationalgeographic.com/animals/article/ogre-faced-spiders-great-hearing-without-ears">hunting spiders</a> detect sound from vibrations with their tiny leg hairs. It’s difficult to tell how sensitive an animal is to noise but what’s most important is whether noise in their environment is within their hearing range, rather than if the animal has a high or low frequency. </p>
<h2>What we know</h2>
<p>Due to a lack of research, we don’t know that much about how precisely noise affects animals but this is what we’ve learnt so far.</p>
<p>Loud noise can <a href="https://asa.scitation.org/doi/full/10.1121/1.5132553">permanently damage lab rodents’ hearing</a>. We can assume this exposure is painful because rats exposed to loud noise behave differently with and without pain medication. Findings in lab rodent studies can be generalised to other mammals but there are known <a href="https://openresearch-repository.anu.edu.au/bitstream/1885/125588/1/AnimalBioacoustics.pdf">differences in hearing ability across different animals</a>. </p>
<p><a href="https://royalsocietypublishing.org/doi/full/10.1098/rsbl.2019.0649">Wild animals</a> suffer chronic stress, fertility problems and change their migration routes in response to noise. Confined animals are often exposed to high levels of human-generated noise which they cannot escape. </p>
<p>Research shows noise causes confined animals <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1461-0248.2011.01664.x?casa_token=xf_WpgiIqa0AAAAA%3AGFBo29v7v4j09Svlfat0SXpHyx62i_xts9XFw1zpIpO31pE2CDA5jhD4ea1HE1erb2koG_jRzuim">pain, fear and cognitive problems</a>. For example <a href="https://pubmed.ncbi.nlm.nih.gov/21392276/">in fish</a>, vibrations from extreme noise can damage the swim bladder which in turn impacts their hearing and buoyancy. Pain and fear are strong indicators of <a href="https://www.sciencedirect.com/science/article/pii/S0168159109000380?casa_token=UJ4h7VP_m4EAAAAA:9pFHAvN3FDJmzvghugSCu-lrCaIk4JdvrsWXUHa4exzaE9rvhHZiyAcr6hUH1tomiBhbHHrU">poor welfare</a>. </p>
<figure class="align-center ">
<img alt="Black and white cat hiding in a paper bag" src="https://images.theconversation.com/files/479870/original/file-20220818-1509-te2ee.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/479870/original/file-20220818-1509-te2ee.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/479870/original/file-20220818-1509-te2ee.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/479870/original/file-20220818-1509-te2ee.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/479870/original/file-20220818-1509-te2ee.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/479870/original/file-20220818-1509-te2ee.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/479870/original/file-20220818-1509-te2ee.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Animals hide when they’re scared.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/black-white-cat-paper-bag-shallow-1109119010">Suzanne Tucker/Shutterstock</a></span>
</figcaption>
</figure>
<p>Inaudible noise (vibrations) can also hurt animals by physically shaking their internal body parts. Farm animals experience high levels of vibration <a href="https://www.sciencedirect.com/science/article/pii/S1537511011000924?casa_token=qfHGf1zxl98AAAAA:og6InWh1IMDrMrdcynMWbG6r4YTEzV-XABaBWMpacmmvgZ_qCF9AXvB309YL5QdC9pmG6u4X">during transport</a>. <a href="https://aru.ac.uk/science-and-engineering/research/institutes-and-groups/behavioural-ecology">Our research group at Anglia Ruskin University</a> is investigating whether vibrations from construction work impacts zoo primates. </p>
<p>One noisy event such as a local music festival or extreme weather can trigger long-term fear in animals. The link between noise and fear has been well studied in dogs using recordings of thunderstorms.</p>
<p>This kind of noise sensitivity, which affects up to <a href="https://www.sciencedirect.com/science/article/pii/S016815911200367X?casa_token=hWzg_YfSMNAAAAAA:Cs1o0BRqlGssuYANFCEhFUcQ8LL5ooZdQUB_Jlqz3U8AGI42qCZ8No9bgre8Uu4nL1OpxFew">50% of pet dogs</a>, is triggered by unexpected noises. It makes animals hide or seek human comfort. <a href="https://www.sciencedirect.com/science/article/abs/pii/S0168159104002163">Farmed hens</a> exposed to vehicle noise and even music also freeze in fear.</p>
<figure class="align-right ">
<img alt="Small monkey with long tail perches in a tree" src="https://images.theconversation.com/files/474969/original/file-20220719-16-guijgt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/474969/original/file-20220719-16-guijgt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=896&fit=crop&dpr=1 600w, https://images.theconversation.com/files/474969/original/file-20220719-16-guijgt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=896&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/474969/original/file-20220719-16-guijgt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=896&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/474969/original/file-20220719-16-guijgt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1126&fit=crop&dpr=1 754w, https://images.theconversation.com/files/474969/original/file-20220719-16-guijgt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1126&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/474969/original/file-20220719-16-guijgt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1126&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">This pied tamarin monkey lives in a public park in Brazil but has no say over local noise regulations.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/Category:Parque_Municipal_do_Mindu">Whaldener Endo, Wikipedia</a></span>
</figcaption>
</figure>
<p>Primates, birds and frogs can adjust in the short term to noisy environments by <a href="https://www.sciencedirect.com/science/article/abs/pii/S0065345405350042">vocalising louder</a>, similar to raising our voices at noisy parties. But the long-term consequences of animals needing to change their methods of communication hasn’t been studied.</p>
<p>Long-term exposure to loud noise reduces <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5843988/">learning and memory ability in lab mice</a>. The <a href="https://wires.onlinelibrary.wiley.com/doi/full/10.1002/wcs.1299?casa_token=fo5L84bKhfIAAAAA%3AVm3yyLwRzY3zAbhKOzApVD_Y4Wqezh36AoZJJf_jCPDVg0plFE2BZFKMdzu5nigHAly6eFmC8fo5">link between cognition and anxiety in humans</a> is complex but generally speaking, high levels of anxiety reduce our ability to perform challenging tasks. </p>
<p>This could be similar in other mammals but there is not enough research to be sure. Studying noise in zoos is difficult because it’s hard to control other factors, like weather and visitor presence. </p>
<h2>How to help</h2>
<p>If your pet is stressed by noise, a <a href="https://bvajournals.onlinelibrary.wiley.com/doi/pdf/10.1136/inpract.27.5.248?casa_token=n-wbQ1WePXAAAAAA:XYRqZATuEMzaI7GAr94ccVkMSBW9TPDQdMAAuvQvKCfC8tTAdqQTc9sjUuB73AVnICL4MKZR1ACA">range of treatments</a> are available to calm or distract them including synthetic pheromones and enrichment toys. But prevention is better than cure. </p>
<p>If you take care of confined animals, pay close attention to human activities that generate noise (such as cleaning and gardening) and how the surroundings may reflect sound waves. Sound waves can be blocked and bounce back from materials like concrete, metal and glass, which makes the noise worse. </p>
<p>You can protect your pets during noisy events, like thunderstorms and firework displays, by providing extra spaces to escape noise. Some soft furnishings like pillows or blankets inside a den help absorb sounds. A pile of blankets to crawl under, even without a den, will help to block out noise. </p>
<p>Better regulation is needed to protect animals from construction work and noisy events. Animals don’t have a say in what building projects or music concerts go ahead but they can suffer the consequences.</p><img src="https://counter.theconversation.com/content/186408/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Noise can be so unpleasant that we regulate construction work and music concerts - but we only consider human hearing ranges.Fay Clark, Research Fellow in Life Sciences, Anglia Ruskin UniversityJacob Dunn, Associate Professor of Evolutionary Biology, Anglia Ruskin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1824412022-08-01T15:29:08Z2022-08-01T15:29:08ZThe tongue: how one of the body’s most sensitive organs is helping blind people ‘see’<figure><img src="https://images.theconversation.com/files/464768/original/file-20220523-26-5xzgxc.jpg?ixlib=rb-1.1.0&rect=165%2C0%2C6312%2C4292&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The tip of the tongue is more sensitive than our fingertips.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/pretty-joyful-african-american-cute-short-2032746725">Anatoliy Karlyuk/Shutterstock</a></span></figcaption></figure><p>Ever wondered why kissing feels better than holding hands? The tongue is a pretty incredible piece of kit, though notoriously difficult to study, due to its position inside the mouth. Obviously, it gives us access to the wonderful world of taste, but more than that, it has greater sensitivity to touch than the fingertip. Without it, we aren’t able to speak, sing, breathe efficiently or swallow delicious beverages. </p>
<p>So why don’t we use it even more? <a href="https://doi.org/10.1037/xhp0001007">My new study</a> investigates how to make the most of this strange organ – potentially as an interface to help people with visual impairments navigate and even exercise. I realise this may sound mindboggling, but please bear with me.</p>
<p>My research is part of a field known as “sensory substitution”, a branch of interdisciplinary science that combines psychology, neuroscience, computer science and engineering to develop “sensory substitution devices” (known as SSDs). SSDs convert sensory information from one sense to another. For example, if the device is designed for a person with a visual impairment, this typically means converting visual information from a video feed into sound or touch. </p>
<h2>Drawing pictures on the tongue</h2>
<p><a href="https://www.researchgate.net/publication/7384990_Brainport_An_alternative_input_to_the_brain">BrainPort</a>, first developed in 1998, is one such technology. It converts a camera’s video feed into moving patterns of electrical stimulation on the surface of the tongue. The “tongue display” (a small device shaped like a lollipop) consists of 400 tiny electrodes, with each electrode corresponding to a pixel from a camera’s video feed. </p>
<p>It creates a low-resolution tactile display on the tongue matching the output from the camera. The technology can be used to help stroke victims maintain their sense of balance. And in 2015, the US Food and Drug Administration approved its use as an <a href="https://www.washingtonpost.com/news/to-your-health/wp/2015/06/18/fda-approves-device-to-help-blind-people-see-by-using-their-tongues/">aid for the visually impaired</a>.</p>
<p>Imagine holding your hand up to a camera and feeling a tiny hand simultaneously appear on the tip of your tongue. It sort of feels a bit like someone is drawing images on your tongue in popping candy. </p>
<p>While the BrainPort has been around for years, it hasn’t seen much real-world uptake, despite being ten times cheaper than a retinal implant. I use the BrainPort to test how human attention works on the surface of the tongue, to see if differences in perception might be the cause of this. </p>
<p>In psychology research, there is a famous method to test attention, called the <a href="https://jov.arvojournals.org/article.aspx?articleid=2121543">Posner Cueing paradigm</a>, named after the American psychologist <a href="https://www.apa.org/monitor/2009/12/posner">Mike Posner</a> who developed it in the 1980s to measure visual attention. </p>
<p>When I say attention, I don’t mean “attention span”. Attention refers to the set of processes that bring things from the environment into our conscious awareness. Posner found that our attention can be cued by visual stimuli. </p>
<p>If we briefly see something moving out of the corner of our eye, attention focuses on that area. We probably evolved this way to quickly react to dangerous snakes lurking around corners and in the edges of our visual field. </p>
<p>This process also occurs between senses. If you’ve ever sat in a pub garden in summer and heard the dreaded drone of an incoming wasp to one ear, your attention is very quickly drawn to that side of your body. </p>
<p>The sound of the wasp captures your auditory attention to the general location of the potentially incoming wasp so that the brain can quickly allocate visual attention to identify the exact location of the wasp, and tactile attention to quickly swat or duck away from the wasp. </p>
<p>This is what we call <a href="https://www.sciencedirect.com/science/article/pii/S1364661398011887">“cross-modal” attention</a> (vision is one mode of sensation, audio another): things that appear in one sense can influence other senses.</p>
<h2>Paying attention to the tongue</h2>
<p>My colleagues and I developed a variation of the Posner Cueing paradigm to see if the brain can allocate tactile attention on the surface of the tongue in the same way as the hands or other modes of attention. We know loads about visual attention, and tactile attention on the hands and other body parts, but have no idea if this knowledge translates to the tongue. </p>
<p>This is important because BrainPort is designed, built and sold to help people “see” through their tongue. But we need to understand if “seeing” with the tongue is the same as seeing with the eyes.</p>
<figure class="align-center ">
<img alt="Image of a blind man talking on the phone." src="https://images.theconversation.com/files/475826/original/file-20220725-18-zuoyzm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/475826/original/file-20220725-18-zuoyzm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/475826/original/file-20220725-18-zuoyzm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/475826/original/file-20220725-18-zuoyzm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/475826/original/file-20220725-18-zuoyzm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/475826/original/file-20220725-18-zuoyzm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/475826/original/file-20220725-18-zuoyzm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">How similar is seeing with the tongue to seeing with the eyes or hands?</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/young-blinded-man-using-phone-sending-1978517621">PH888/Shutterstock</a></span>
</figcaption>
</figure>
<p>The answer to these questions, like almost everything in life, is that it’s complicated. The tongue does respond to cued information in roughly the same way as the hands or vision, but despite the incredible sensitivity of the tongue, attentional processes are a bit limited compared with the other senses. It is very easy to over-stimulate the tongue – causing sensory overload that can make it hard to feel what’s going on.</p>
<p>We also found that attentional processes on the tongue can be influenced by sound. For example, if a BrainPort user hears a sound to the left they can more easily identify information on the left side of their tongue. This could help to guide attention and reduce sensory overload with the BrainPort if paired with an auditory interface. </p>
<p>In terms of real-world use of the BrainPort, this translates to managing the complexity of visual information that gets substituted and, if possible, use another sense to help share some of the sensory load. Using the BrainPort in isolation could be too overstimulating to provide reliable information and could potentially be improved by using other assistive technology alongside, such as the <a href="https://theconversation.com/blind-people-can-see-bodies-with-sound-study-24008">vOICe</a>. </p>
<p>We’re using these findings to develop a device to help rock climbers with visual impairments to <a href="https://dl.acm.org/doi/abs/10.1145/3491101.3519680">navigate while climbing</a>. To prevent information overload, we’re using machine learning to identify climbing holds and filter out less relevant information. We’re also exploring the possibility of using sound to cue where the next hold might be, and then use the feedback on the tongue to precisely locate the hold. </p>
<p>With a few tweaks, this technology may eventually become a more reliable instrument to help blind or deaf or blind people navigate. It may even help paraplegic people, unable to use their hands, navigate or communicate more efficiently.</p><img src="https://counter.theconversation.com/content/182441/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mike Richardson's PhD project was funded by the E.S.R.C. as part of a scholarship. He is also currently employed as a Research Associate at the University of Bath, where he is funded by MyWorld.</span></em></p>A device could be use to transmit a camera’s video feed into moving patterns of electrical stimulation on the surface of the tongue.Mike Richardson, Research Associate in Psychology, University of BathLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1834222022-06-06T19:23:38Z2022-06-06T19:23:38ZNovel in-ear technology could allow chewing to replace the batteries in hearing aids<figure><img src="https://images.theconversation.com/files/464090/original/file-20220518-15-3que7x.jpg?ixlib=rb-1.1.0&rect=7%2C0%2C988%2C736&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Whenever we eat, speak or yawn, the movement of our jaw deforms the ear canal. These deformations could be converted into electrical energy used to power in-ear technology.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>Hearing aids are essential for people with hearing loss. But hearing aids have an Achilles heel: their power supply is expensive and environmentally unfriendly. </p>
<p>The good news is that researchers have found an renewable, alternative energy source that might be able to power hearing aids. The energy is produced inside the ear, and harvested using an earplug embedded with sensors.</p>
<p>My PhD project consists of modelling the deformations of the ear canal created by the movements of the jaw. My results will contribute to a better evaluation of the energy that might come from these deformations.</p>
<h2>The problem with hearing aids</h2>
<p>To understand the problem with hearing aids, consider the daily life of Clara, a 24-year-old architecture student, who has been wearing hearing aids since she was eight years old. When the battery that powers her prosthesis runs out, Clara loses hearing and is cut off from the world. </p>
<p>A part of her brain is constantly on alert to make sure she has a spare box of batteries on hand. In addition to this hassle, the battery is an economic burden. Considering her battery consumption and the price per battery, Clara estimates that in 15 years, the batteries cost more than purchasing a new hearing aid.</p>
<p>The same goes for the cost to the environment. The <a href="https://theconversation.com/demand-for-rare-earth-metals-is-skyrocketing-so-were-creating-a-safer-cleaner-way-to-recover-them-from-old-phones-and-laptops-141360">rare metals</a> used in batteries are not recyclable at this time, and many batteries end up in landfills.</p>
<p>Rechargeable batteries are now widely used for wireless headphones, making it surprising that hearing aids have not embraced this technology. It might sound strange to compare wireless earphones with hearing aids, but in terms of sophistication, the only advantage earphones have over hearing aids is the audio amplifier, which makes it possible to increase sound volume in the ear.</p>
<p>The big difference is price. A single hearing aid costs $1,000-2,000 compared to $100-300 for a pair of headphones. <a href="http://www.nickhunn.com/wp-content/uploads/downloads/2016/11/The-Market-for-Hearable-Devices-2016-2020.pdf">The business model, which involves manufacturers, medical insurers, hearing care professionals and consumers, keeps the price hight</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/RiVx5Lih_44?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">How our hearing system works.</span></figcaption>
</figure>
<p>In short, it’s fair to say that Clara’s financial and environmental balance sheets are not positive. But the revolution is coming! She may soon be able to power her hearing aids with the movement of her jaw.</p>
<h2>Our ear canals create energy</h2>
<p>Here’s a small experiment: insert your little finger in your ear, then open and close your mouth. Do you feel the pressure change on your fingertip? Jaw movement compresses the tissues around the ear canal, changing its shape. Researchers propose converting this deformation inside the ear into electrical energy.</p>
<p>Several studies have evaluated the amount of energy that comes from this deformation, and have obtained encouraging results. The <a href="https://ieeexplore.ieee.org/document/9018039/">most recent study</a> reports that up to 22 per cent of the <a href="https://doi.org/10.1016/S0378-7753(00)00378-5">energy needed for the daily operation of a hearing aid</a> can be generated during a 10-minute lunch break. </p>
<p>In other words, the action of eating for 50 minutes would be enough to generate all the energy necessary for a day’s use of the hearing aid. For this experiment, the researchers placed an earplug filled with water in the ear of the participants. They then measured the pressure in the earplug created by the jaw movements. Finally, they translated these pressure variations into deformations of the ear canal.</p>
<p>The human body still holds many surprises. For one, it is a sustainable source of energy available at any time. Just as photovoltaic panels use solar energy, there are now technologies that harvest energy from the human body. This is the case with automatic watches that use the kinetic energy produced by wrist movements.</p>
<p>When it comes to hearing aids, other studies have attempted to <a href="http://ieeexplore.ieee.org/document/5167942/">convert thermal energy close to the ear</a> or to place a mini solar panel in the ear. But most interest has been in converting energy from ear canal deformations.</p>
<h2>In search of the ideal converter</h2>
<p>One question remains unanswered: How can the harvested energy be converted and stored? The deformations in the auditory canal are mechanical energy, and the energy can only be stored in a battery after it has been transformed into electric energy. </p>
<p>To solve this problem, researchers have placed <a href="https://ieeexplore.ieee.org/document/6420936/">ribbons of piezoelectric materials along the perimeter of the earplugs</a>. These materials creating an electric signal when they are deformed.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/463327/original/file-20220516-13-i6i454.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="different types of hearing aids" src="https://images.theconversation.com/files/463327/original/file-20220516-13-i6i454.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/463327/original/file-20220516-13-i6i454.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/463327/original/file-20220516-13-i6i454.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/463327/original/file-20220516-13-i6i454.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/463327/original/file-20220516-13-i6i454.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/463327/original/file-20220516-13-i6i454.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/463327/original/file-20220516-13-i6i454.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Hearing aids are used by many people with hearing loss, but their energy supply is a weak point in their design.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Unfortunately, the prototypes tested so far do not yet convert enough energy. Some devices come close to the target amount, but they are not small enough to be integrated into a hearing aid. The development of flexible printed circuit boards that can adjust to shapes will make self-powered medical implants possible. With these advances, more efficient converters will begin to emerge.</p>
<h2>Will the hearing aid market soon be revolutionized?</h2>
<p>If the earplugs of Clara’s hearing aids could convert the deformations of her ear canal into electrical energy, Clara would be able to go about daily life without worrying about recharging her devices. She would know that in case of a power failure, all she has to do is chew gum or hum her favourite song. </p>
<p>This technology could also help reduce the cost of hearing aids, which would be of particular benefit to the <a href="https://www150.statcan.gc.ca/n1/pub/11-627-m/11-627-m2019025-fra.htm">200,000 Canadians with hearing loss who do not use hearing aids because of their high cost</a>.</p>
<p>What’s more, this technology could be extended to all technologies that are worn near or inside the ear, such as wireless headphones or earpieces, digital hearing protectors, in-ear sensors or augmented reality glasses. It doesn’t cost anything to dream!</p><img src="https://counter.theconversation.com/content/183422/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michel Demuynck received a research grant from a Discovery Grant obtained by his thesis supervisor from NSERC. In parallel to his thesis, Michel worked for EERS Global, a partner company of the CRITIAS industrial research chair, which develops technologies for hearing protection and communication in noise.</span></em></p>We have underestimated the energy potential of our ears: deformations in the ear canal could be used to power in-ear technologies.Michel Demuynck, Candidat au doctorat en biomécanique, École de technologie supérieure (ÉTS)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1827112022-05-19T13:04:08Z2022-05-19T13:04:08ZTinnitus seems linked with sleep – understanding how could bring us closer to finding a cure<figure><img src="https://images.theconversation.com/files/463966/original/file-20220518-23-3arb2t.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6720%2C4466&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">People with tinnitus are more likely to have disturbed sleep. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/cant-sleep-portrait-irritated-young-black-2049529997">Prostock-studio/ Shutterstock</a></span></figcaption></figure><p>Around <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(13)60142-7/fulltext">15% of the world’s population</a> suffers from tinnitus, a condition which causes someone to hear a sound (such as ringing or buzzing) without any external source. It’s often associated with <a href="https://rnid.org.uk/information-and-support/tinnitus/tinnitus-causes/">hearing loss</a>. </p>
<p>Not only can the condition be annoying for sufferers, it can also have a serious effect on mental health, often causing <a href="https://www.tinnitus.org.uk/tinnitus-and-stress">stress</a> or <a href="https://pubmed.ncbi.nlm.nih.gov/30909841/">depression</a>. This is especially the case for patients suffering from tinnitus over months or years. </p>
<p>There’s currently <a href="https://www.frontiersin.org/articles/10.3389/fnins.2019.00802/full">no cure for tinnitus</a>. So finding a way to better manage or treat it could help many millions of people worldwide. </p>
<p>And one area of research that may help us better understand tinnitus is sleep. There are many reasons for this. First, tinnitus is a phantom percept. This is when our brain activity makes us see, hear or smell things that aren’t there. Most people only experience phantom perceptions <a href="https://www.sleepfoundation.org/dreams">when they’re asleep</a>. But for people with tinnitus, they hear phantom sounds while they’re awake. </p>
<p>The second reason is because tinnitus <a href="https://pubmed.ncbi.nlm.nih.gov/26373470/">alters brain activity</a>, with certain areas of the brain (such as those involved in hearing) potentially being more active than they should be. This may also explain how phantom percepts happen. When we sleep, activity in these same brain areas also changes.</p>
<p>Our <a href="https://academic.oup.com/braincomms/article/4/3/fcac089/6563428?login=false">recent research review</a> has identified a couple of brain mechanisms that underlie both tinnitus and sleep. Better understanding these mechanisms – and the way the two are connected – could one day help us find ways of managing and treating tinnitus. </p>
<h2>Sleep and tinnitus</h2>
<p>When we fall asleep, our body experiences multiple stages of sleep. One of the most important stages of sleep is <a href="https://pubmed.ncbi.nlm.nih.gov/22811426/">slow-wave sleep</a> (also known as deep sleep), which is thought to be the most restful stage of sleep.</p>
<p>During slow-wave sleep, brain activity moves in distinctive “waves” through the different areas of the brain, activating large areas together (such as those involved with memory and processing sounds) before moving on to others. It’s thought that slow-wave sleep allows the brain’s neurons (specialised brain cells which send and receive information) to recover from daily wear and tear, while also helping sleep make us feel rested. It’s also thought to be important for our <a href="https://pubmed.ncbi.nlm.nih.gov/30923474/">memory</a>.</p>
<p>Not every area of the brain experiences the same amount of slow-wave activity. It’s <a href="https://pubmed.ncbi.nlm.nih.gov/15184907/">most pronounced</a> in areas we use most while awake, such as those important for <a href="https://www.nature.com/articles/nature10009">motor function</a> and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3524543/">sight</a>. </p>
<p>But sometimes, certain brain areas can be overactive during slow-wave sleep. This is what happens in sleep disorders such as <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5806559">sleep walking</a>. </p>
<p>A similar thing may happen in people with tinnitus. We think that hyperactive brain regions might stay awake in the otherwise sleeping brain. This would explain why many people with tinnitus experience <a href="https://pubmed.ncbi.nlm.nih.gov/8373941/">disturbed sleep</a> and <a href="https://www.sciencedirect.com/science/article/pii/S0929664620301066">night terrors</a> more often than people who don’t have tinnitus. </p>
<p>Tinnitus patients also spend more time in <a href="https://pubmed.ncbi.nlm.nih.gov/24005841/">light sleep</a>. Simply put, we believe that tinnitus keeps the brain from producing the slow-wave activity needed to have a deep sleep, resulting in light and interrupted sleep. </p>
<figure class="align-center ">
<img alt="A cartoon image depicting the affect that local wakefulness can have on the sleeping brain." src="https://images.theconversation.com/files/463965/original/file-20220518-15-35k8ld.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/463965/original/file-20220518-15-35k8ld.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=558&fit=crop&dpr=1 600w, https://images.theconversation.com/files/463965/original/file-20220518-15-35k8ld.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=558&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/463965/original/file-20220518-15-35k8ld.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=558&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/463965/original/file-20220518-15-35k8ld.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=701&fit=crop&dpr=1 754w, https://images.theconversation.com/files/463965/original/file-20220518-15-35k8ld.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=701&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/463965/original/file-20220518-15-35k8ld.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=701&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Some areas of the brain can be overactive in tinnitus, which may cause sleep disturbances.</span>
<span class="attribution"><span class="source">Linus Milinski</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>But even though tinnitus patients have <a href="https://pubmed.ncbi.nlm.nih.gov/24005841/">less deep sleep on average</a> than people without tinnitus, the research we looked at in our review suggests that some deep sleep is hardly affected by tinnitus. This may be because the brain activity that happens during the deepest sleep actually suppresses tinnitus.</p>
<p>There are a couple of ways the brain may be able to suppress tinnitus during deep sleep. The first has to do with the brain’s neurons. After a long period of wakefulness neurons in the brain are thought to switch into slow-wave activity mode to recover. The more neurons in this mode together, the stronger the drive is for the rest of the brain to join. </p>
<p>We know that the drive for sleep can get strong enough that neurons in the brain will eventually go into slow-wave activity mode. And since this especially applies to brain regions overactive during wakefulness, we think that tinnitus might be suppressed as a result of that.</p>
<p>Slow-wave activity has also been shown to interfere with the <a href="https://pubmed.ncbi.nlm.nih.gov/30356042/">communication between brain areas </a>. During deepest sleep, when slow-wave activity is strongest, this may keep hyperactive regions from disturbing other brain areas and from interrupting sleep. </p>
<p>This would explain why people with tinnitus can still enter deep sleep, and why tinnitus may be suppressed during that time. </p>
<p>Sleep is also important for strengthening our memory, by helping to drive <a href="https://pubmed.ncbi.nlm.nih.gov/11343661/">changes in connections</a> between neurons in the brain. We believe that changes in brain connectivity during sleep are contributing to what makes tinnitus last for a long time after an initial trigger (such as hearing loss). </p>
<h2>Treating tinnitus</h2>
<p>We already know that intensity of tinnitus can change throughout a given day. Investigating how tinnitus changes during sleep could give us a direct handle on what the brain does to cause fluctuations in tinnitus intensity. </p>
<p>It also means that we may be able to manipulate sleep to improve the wellbeing of patients – and possibly develop new treatments for tinnitus. For example, sleep disruptions can be reduced and slow-wave activity can be boosted through <a href="https://pubmed.ncbi.nlm.nih.gov/33984745/">sleep restriction paradigms</a>, where patients are told to only go to bed when they’re actually tired. Boosting the intensity of sleep could help us better see the effect sleep has on tinnitus.</p>
<p>While we suspect that deep sleep is the most likely to affect tinnitus, there are many other stages of sleep that happen (such as rapid eye movement, or REM sleep) – each with unique patterns of brain activity. In future research, both the sleep stage and tinnitus activity in the brain could be tracked at the same time by recording brain activity. This may help to find out more about the link between tinnitus and sleep and understand how tinnitus may be alleviated by natural brain activity.</p><img src="https://counter.theconversation.com/content/182711/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Linus Milinski received funding from the Royal National Institute for Deaf People (RNID).</span></em></p><p class="fine-print"><em><span>Fernando Nodal's research is funded by the Wellcome Trust. </span></em></p><p class="fine-print"><em><span>Victoria Bajo Lorenzana's research is funded by the Royal National Institute for Deaf People (RNID) and by the Wellcome Trust.</span></em></p><p class="fine-print"><em><span>Vladyslav Vyazovskiy receives research funding from the Medical Research Council. </span></em></p>Understanding why the two are connected could be key in finding treatments – or even a cure – for tinnitusLinus Milinski, Doctoral Researcher in Neuroscience, University of OxfordFernando Nodal, Departmental Lecturer, Auditory Neuroscience Group, University of OxfordVictoria Bajo Lorenzana, Associate Professor of Neuroscience, University of OxfordVladyslav Vyazovskiy, Professor of Sleep Physiology, University of OxfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1775832022-03-10T11:28:40Z2022-03-10T11:28:40ZIf you love ASMR you might be more sensitive, our research finds<p>Do you ever experience a tingling sensation in your scalp when someone whispers? </p>
<p>If you recognise that feeling, then you may well be acquainted with the phenomenon that’s gathered millions of followers over the last few years, and has been dubbed “autonomous sensory meridian response” (<a href="https://theasmr.com/what-is-asmr-meaning/">ASMR</a>). </p>
<p>For those of you who haven’t heard of ASMR, it’s a relaxing head-orientated tingling sensation that some people experience in response to various sensory “triggers”. It could be watching someone brush hair, or fold laundry with care and expertise or certain sounds like whispering or tapping. And in everyday life, one of the most common triggers is actually soft touch – like stroking someone’s arm or tracing fingers on the back.</p>
<p>Some people <a href="https://www.ncbi.nlm.nih.gov/books/NBK453209/#:%7E:text=Their%20results%20indicated%20that%20the,effect%20of%20ASMR%20on%20mood">report experiencing</a> ASMR for “as long as they can remember” – but the explosion of <a href="https://ahrefs.com/blog/top-youtube-searches/">online ASMR videos</a> is allowing people to tap into the sensation on-demand rather than having to wait for it to happen as they go about their daily lives. And many people (even those that don’t experience ASMR tingling) may use them for relaxation and sleep. </p>
<p>But an intriguing question that remains unanswered is why only some people experience ASMR tingling.</p>
<p>We recently conducted <a href="https://www.sciencedirect.com/science/article/abs/pii/S0092656621001203">a study</a> which goes some way towards answering this question. It seems that people who experience ASMR have heightened sensory sensitivity – that is, they are more sensitive to what’s going on around them, and inside them. Here’s how we found out, and what it means.</p>
<h2>Sensitivity explained</h2>
<p>We all differ in <a href="https://www.tandfonline.com/doi/pdf/10.1080/17588928.2018.1557131?casa_token=yRKIJyIeo1AAAAAA:6yggeDHHK-H9JzT0ewFypPEfwhuVR-WymeFJOt18QqN5jAZkCt-hq2FMzCvokdC4pSWp-UkEkV9HsQ">how sensitive</a> we are to information from our five external senses (touch, sight, hearing, smell and taste). If you’re highly sensitive to external input you might be disgusted at the strong smell of an aftershave as you pass someone in the street, for example. </p>
<p>We also vary in sensitivity to our body’s internal state, such as whether we’re feeling hungry or cold. </p>
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<strong>
Read more:
<a href="https://theconversation.com/differences-in-how-men-and-women-perceive-internal-body-signals-could-have-implications-for-mental-health-172917">Differences in how men and women perceive internal body signals could have implications for mental health</a>
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<p>So, to investigate whether people with ASMR are more “sensitive”, we tested participants using the most commonly used measures of internal and external sensory sensitivity. The <a href="https://www.pearsonclinical.co.uk/store/ukassessments/en/Store/Professional-Assessments/Motor-Sensory/Adolescent-Adult-Sensory-Profile/p/P100009054.html">adult sensory profile</a>, for example, asked participants to rate their response in numerous situations (such as how well they work with background noise or whether they startle easily at unexpected or loud noises). </p>
<p>We also assessed whether participants experience ASMR when exposed to 16 common triggers, and if so, the strength of their ASMR response and how they experienced it.</p>
<h2>Sensitivity links to ASMR</h2>
<p>It turned out that people who experience ASMR showed much higher levels of sensory sensitivity than people without ASMR.</p>
<p>They report hypersensitivity and negative responses to external stimuli such as noise and movement, and are easily overstimulated by their environment. They also show higher levels of body awareness and greater sensitivity to internal bodily sensations – noticing how their body changes when they feel happy, for example.</p>
<p>And the strength of their ASMR response was also associated with heightened external sensitivity and greater control over their attention towards their body and emotional state. </p>
<p>We think that the concept of the “highly sensitive person” (<a href="https://www.sciencedirect.com/science/article/pii/S0149763418306250">HSP</a>) may be central for differentiating ASMR responders from non-responders. </p>
<p>Using a <a href="https://sensitivityresearch.com/about-sensitivity/">flower metaphor</a>, developed by researchers to distinguish between people who have different levels of sensitivity – both internal and to the external social environment, such as people and visual stimuli – our study found that 56% of ASMR responders were categorised as highly sensitive “orchids” (who do well in ideal conditions but badly in poor conditions) with only 12% categorised as the environmentally resilient “dandelions”. The remainder were “tulips” who lie somewhere in between. </p>
<p>This contrasts with other studies suggesting that highly sensitive orchids usually make up around <a href="https://www.nature.com/articles/s41398-017-0090-6">30% of the population</a>.</p>
<p>As people with ASMR are more likely to be classified as highly sensitive, that might go some way towards explaining why ASMR has been linked to empathy. HSPs process social information more deeply which is <a href="https://onlinelibrary.wiley.com/doi/pdf/10.1002/brb3.242">thought to underpin</a> their ability to be more attuned and responsive to others’ emotions and needs. Future research may find similar enhanced social and emotional processing abilities in people with ASMR, but this needs to be properly investigated. </p>
<p>ASMR has been shown to enhance feelings of <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0196645">social connection</a> and the strongest ASMR triggers often simulate situations involving interpersonal closeness, intimacy, and touch. It may be that people who experience ASMR also derive more emotional benefit from social interactions. One fascinating possibility is that the tingling of ASMR reflects the ability to simulate <a href="https://www.sciencedirect.com/science/article/abs/pii/S0149763408001723?casa_token=2hTSpDq2tc0AAAAA:Hpy-wHdfNID3u6-JOk_SVflJQ02lR9mdSmRqrQiXJDa1J4_Sc0erl5jjGDLmXpffj-6uEouKFnw">social touch</a> and its benefits – such as stress reduction and mental well-being – from non-tactile stimuli. </p>
<p>There is one intriguing paradox: the same people who experience and enjoy ASMR triggers can often also be repulsed by the same sounds in different circumstances. ASMR-sensitive people have <a href="https://peerj.com/articles/3846/">elevated levels</a> of misophonia (a condition describing aversive and <a href="https://pubmed.ncbi.nlm.nih.gov/28561277/">angry feelings</a> in response to certain sounds, such as tapping, chewing or lip smacking), with 43% experiencing it. </p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/asmr-what-we-know-so-far-about-this-unique-brain-phenomenon-and-what-we-dont-135106">ASMR: what we know so far about this unique brain phenomenon – and what we don't</a>
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</p>
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<p>If the same trigger sounds elicit opposite emotional reactions in the same people, then this could mean that there isn’t anything inherently pleasant or unpleasant about the sounds themselves. </p>
<p>Our findings suggest that one reason for this seemingly odd co-occurrence might be because both ASMR and misophonia are underlined by increased sensory sensitivity, especially to sound. The situation, and how the sensory information is translated into an emotional response, might then determine whether the same sound is evaluated as positive or negative by the same person. Being sensitive has many benefits – but as with all things in life, it has its complications too.</p><img src="https://counter.theconversation.com/content/177583/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Giulia Poerio does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>It’s intriguing how some people experience ASMR while others don’t - our latest research suggests that many ASMR responders are highly sensitive “orchids”.Giulia Poerio, Associate lecturer, University of EssexLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1711712021-11-24T14:44:52Z2021-11-24T14:44:52ZGreat headphones blend physics, anatomy and psychology – but what you like to listen to is also important for choosing the right pair<figure><img src="https://images.theconversation.com/files/433547/original/file-20211123-18-1o2lao8.jpg?ixlib=rb-1.1.0&rect=82%2C112%2C3448%2C3050&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Headphone designers have to balance scientific limitations with human preferences.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/close-up-of-headphones-on-microphone-stand-in-royalty-free-image/743693059?adppopup=true">Vladimir Godnik via Getty Images</a></span></figcaption></figure><p>Between music, podcasts, gaming and the unlimited supply of online content, most people <a href="https://brandongaille.com/23-headphone-industry-statistics-and-trends/">spend hours a week wearing headphones</a>. Perhaps you are considering a new pair for the holidays, but with so many options on the market, it can be hard to know what to choose.</p>
<p>I am a professional musician and a professor of <a href="https://et.iupui.edu/people/hsut">music technology who studies acoustics</a>. My work investigates the intersection between <a href="https://www.aes.org/e-lib/online/browse.cfm?elib=14210">the scientific</a>, artistic and <a href="https://www.aes.org/e-lib/browse.cfm?elib=19774">subjective human elements</a> of sound. Choosing the right headphones involves considering all three of those aspects, so what makes for a truly good pair?</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/433529/original/file-20211123-20-iz3eja.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A diagram showing a wave and areas of higher density and lower density dots." src="https://images.theconversation.com/files/433529/original/file-20211123-20-iz3eja.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/433529/original/file-20211123-20-iz3eja.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=261&fit=crop&dpr=1 600w, https://images.theconversation.com/files/433529/original/file-20211123-20-iz3eja.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=261&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/433529/original/file-20211123-20-iz3eja.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=261&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/433529/original/file-20211123-20-iz3eja.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=328&fit=crop&dpr=1 754w, https://images.theconversation.com/files/433529/original/file-20211123-20-iz3eja.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=328&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/433529/original/file-20211123-20-iz3eja.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=328&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sound is simply a series of low pressure and high pressure areas where air molecules, represented by the small dots, compress or spread apart.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:CPT-sound-physical-manifestation.svg#/media/File:CPT-sound-physical-manifestation.svg">Pluke/WikimediaCommons</a></span>
</figcaption>
</figure>
<h2>What is sound really?</h2>
<p>In physics, sound is made of air vibrations consisting of a series of high and low pressure zones. These are the cycles of a sound wave.</p>
<p>Counting the number of cycles that occur per second <a href="https://www.pearson.com/us/higher-education/program/Rossing-Science-of-Sound-The-3rd-Edition/PGM175267.html">determines the frequency, or pitch, of the sound</a>. Higher frequencies mean higher pitches. Scientists describe frequencies in hertz, so a 500 Hz sound goes through 500 complete cycles of low pressure and high pressure per second. </p>
<p>The loudness, or amplitude, of a sound is determined by the maximum pressure of a wave. The higher the pressure, the louder the sound. </p>
<p>To create sound, headphones turn an electrical audio signal into these cycles of high and low pressure that our ears interpret as sound.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/433533/original/file-20211123-13-12mj28o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A diagram of a human ear." src="https://images.theconversation.com/files/433533/original/file-20211123-13-12mj28o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/433533/original/file-20211123-13-12mj28o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=455&fit=crop&dpr=1 600w, https://images.theconversation.com/files/433533/original/file-20211123-13-12mj28o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=455&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/433533/original/file-20211123-13-12mj28o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=455&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/433533/original/file-20211123-13-12mj28o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=572&fit=crop&dpr=1 754w, https://images.theconversation.com/files/433533/original/file-20211123-13-12mj28o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=572&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/433533/original/file-20211123-13-12mj28o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=572&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The human ear is a complex system that turns vibrations in the air into electrical signals that go to the brain.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Ear-anatomy-text-small-en.svg#/media/File:Ear-anatomy-text-small-en.svg">Iain/WikimediaCommons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>The human ear</h2>
<p>Human ears are incredible sensors. The average person can hear a huge range of pitches and different levels of loudness. So how does the ear work?</p>
<p>When sound enters your ear, your eardrum translates the air vibrations into mechanical vibrations of the tiny middle ear bones. These mechanical vibrations become fluid vibrations in your inner ear. Sensitive nerves then turn those vibrations into electrical signals that your brain interprets as sound. </p>
<p>Although people can hear a range of pitches roughly from 20 Hz to 20,000 Hz, human hearing <a href="https://doi.org/10.1002/j.1538-7305.1933.tb00403.x">does not respond equally well at all frequencies</a>. </p>
<p>For example, if a low frequency rumble and a higher pitched bird have the same loudness, you would actually perceive the rumble to be quieter than the bird. Generally speaking, the human ear is <a href="https://doi.org/10.1121/1.1915637">more sensitive to middle frequencies than low or high pitches</a>. Researchers think this may be <a href="https://theconversation.com/testing-ancient-human-hearing-via-fossilized-ear-bones-47973">due to evolutionary factors</a>.</p>
<p>Most people don’t know that hearing sensitivity varies and, frankly, would never need to consider this phenomenon – it is simply how people hear. But headphone engineers definitely need to consider how human perception differs from pure physics. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/433537/original/file-20211123-17-nmyltx.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A cutaway diagram of a speaker." src="https://images.theconversation.com/files/433537/original/file-20211123-17-nmyltx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/433537/original/file-20211123-17-nmyltx.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=820&fit=crop&dpr=1 600w, https://images.theconversation.com/files/433537/original/file-20211123-17-nmyltx.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=820&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/433537/original/file-20211123-17-nmyltx.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=820&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/433537/original/file-20211123-17-nmyltx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1030&fit=crop&dpr=1 754w, https://images.theconversation.com/files/433537/original/file-20211123-17-nmyltx.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1030&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/433537/original/file-20211123-17-nmyltx.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1030&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Speakers are fundamentally made of four components, a magnet (1), a coiled wire (2), a spring or suspension (3) and a diaphragm (4).</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Loudspeaker-bass.png#/media/File:Loudspeaker-bass.png">Svjo/WkimediaCommons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>How do headphones work?</h2>
<p>Headphones – both bigger varieties that sit over your ears as well as small earbuds – are just small speakers. Simply put, speakers do the opposite of your ear: They convert the electrical signals from your phone, record player or computer into vibrations in air. </p>
<p>Most speakers are made of four components: a stationary magnet, a wire coil that moves back and forth around that magnet, a diaphragm that pushes air and a suspension that holds the diaphragm.</p>
<p>Electromagnetism states that when a wire is wrapped around a magnet and the current within the wire changes, the <a href="https://www.sciencedirect.com/book/9780240809694/handbook-for-sound-engineers">magnetic field around the wire changes proportionally</a>. When the electrical signal of a song or podcast pulses through the wires in a set of headphones, it changes the current and moves the magnet. The magnet then moves the diaphragm in and out – kind of like a plunger – pushing and compressing air, creating pulses of high pressure and low pressure. This is the music that you hear.</p>
<p>Ideally, a speaker would convert the electrical signals of the input perfectly into sound representations. However, the real physical world has limitations. Things like the size and material of the magnet and diaphragm all prevent a speaker from perfectly matching its output to its input. This leads to distortion and some frequencies being louder or softer than the original. </p>
<p>While no headphone can perfectly recreate the signal, there are infinite different ways to choose to distort that signal. The reason two equally expensive headphones can sound or feel different is that they distort things in different ways. When engineers build new headphones, they have to not only consider how human hearing distorts sound, but also the physical limitations of any speaker.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/433542/original/file-20211123-21-1kgd80t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A man outside wearing headphones." src="https://images.theconversation.com/files/433542/original/file-20211123-21-1kgd80t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/433542/original/file-20211123-21-1kgd80t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/433542/original/file-20211123-21-1kgd80t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/433542/original/file-20211123-21-1kgd80t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/433542/original/file-20211123-21-1kgd80t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/433542/original/file-20211123-21-1kgd80t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/433542/original/file-20211123-21-1kgd80t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">What you like to listen to and how you like your headphones to sound play a huge role in determining what makes for a ‘good’ pair of headphones.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/rear-view-of-man-listening-to-headphones-at-beach-royalty-free-image/543201647?adppopup=true">Matt Dutile/Image Source via Getty Images</a></span>
</figcaption>
</figure>
<h2>Listener preference</h2>
<p>If all the complications of ears and speakers weren’t enough, listeners themselves play a huge role in deciding what makes for a “good” pair of headphones. Aspects like age, experience, culture and music genre preference <a href="http://www.aes.org/e-lib/browse.cfm?elib=17500">all affect what kind of frequency distortion someone will prefer</a>. Headphones are as much <a href="https://www.aes.org/e-lib/online/browse.cfm?elib=16768">a question of personal taste</a> as anything else. </p>
<p>For example, some people prefer bass-heavy headphones for hip-hop music, while classical music listeners may want less frequency distortion. But music or recreational listening aren’t the only things to consider. Headphones for the hearing impaired may highlight frequencies from approximately 1,000 Hz to 5,000 Hz, as <a href="https://doi.org/10.1044/1059-0889.0603.48">this helps to make speech more understandable</a>.</p>
<p>You could certainly play a hip-hop song through headphones designed for the hearing impaired, but most people would agree that the results aren’t going to sound very good. Making sure the headphones you choose match how you are going to use them goes a long way in determining what will sound good.</p>
<p>Ultimately, the science of headphone design, the artistry of the content creators and the human experience all intersect to form the perception of “good” headphones. Despite all these moving pieces, there is one foolproof way to know when headphones are good: choose a good song and put a pair on! Because when all the attributes align, a good pair of headphones can give you the opportunity to be transformed by sound.</p><img src="https://counter.theconversation.com/content/171171/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Timothy Hsu is a member of the Acoustical Society of America and an executive board member for the Indiana Section of the Audio Engineering Society.</span></em></p>There is a lot to consider when buying a new pair of headphones. A professional musician and acoustics researcher explains how the science of sound and quirks of human hearing make for a great listening experience.Timothy Hsu, Assistant Professor of Music and Arts Technology, IUPUILicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1687422021-10-08T04:02:24Z2021-10-08T04:02:24ZDon’t wear earphones all day – your ears need to breathe<figure><img src="https://images.theconversation.com/files/425366/original/file-20211008-19107-vb1res.jpg?ixlib=rb-1.1.0&rect=56%2C0%2C6174%2C4156&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://image.shutterstock.com/image-photo/new-apple-airpods-pro-outdoor-260nw-1588935502.jpg">Shutterstock</a></span></figcaption></figure><p>Wireless earphone sales are booming, with Apple alone selling an estimated <a href="https://www.businessofapps.com/data/apple-statistics/">100 million sets of AirPods</a> in 2020. Being untethered from our phones or devices means we are likely to wear earphones for longer periods.</p>
<p>As a result, you might notice your ears feeling more sticky or waxy. Is this common? And what happens to our ears when we wear earphones?</p>
<p>Although wireless earphones are fairly new to the market, there is a large amount of research investigating the long-term use of <a href="https://pubmed.ncbi.nlm.nih.gov/28846265/">hearing aids</a>, which in many cases, have a similar mechanism. From this research, it appears prolonged use of in-ear devices can cause problems with <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4356173/">earwax</a>.</p>
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Read more:
<a href="https://theconversation.com/are-your-kids-using-headphones-more-during-the-pandemic-heres-how-to-protect-their-ears-139392">Are your kids using headphones more during the pandemic? Here's how to protect their ears</a>
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<h2>What does earwax do?</h2>
<p>The production of earwax (also known as <a href="https://www.ncbi.nlm.nih.gov/books/NBK448155/">cerumen</a>) is a normal process in humans and many other mammals. There should always be a thin coating of wax near the opening of the ear canal.</p>
<p>This wax is a waterproof and protective secretion. This acts to moisten the skin of the external ear canal and works as a protective mechanism to prevent infection, providing a barrier for <a href="https://www.ncbi.nlm.nih.gov/books/NBK448155/">insects, bacteria, and water</a>. Wet earwax is brown and sticky, whereas the dry type is more of a white colour.</p>
<p>In fact, earwax is such a great barrier, in the 1800s there were reports of it being used as an effective balm for <a href="https://theconversation.com/what-causes-dry-lips-and-how-can-you-treat-them-does-lip-balm-actually-help-161264">chapped lips</a>!</p>
<p>Earwax is a naturally occurring substance produced in the external portion of the <a href="https://www.ncbi.nlm.nih.gov/books/NBK459335/">ear canal</a>. It is created by the secretions of <a href="https://pubmed.ncbi.nlm.nih.gov/9433685/">oil glands and sweat glands</a> released by the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4356173/">hair follicles</a>, which then traps dust, bacteria, fungi, hairs and dead skin cells to form the wax. </p>
<p>The external ear canal can be thought of as an escalator system, with the wax always moving towards the outside, preventing the ears from becoming filled with dead skin cells.</p>
<p>This migration of earwax is also aided by natural jaw movements. Once the earwax reaches the end of the ear, it simply falls out.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/424964/original/file-20211006-14-1xe7qte.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/424964/original/file-20211006-14-1xe7qte.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=429&fit=crop&dpr=1 600w, https://images.theconversation.com/files/424964/original/file-20211006-14-1xe7qte.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=429&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/424964/original/file-20211006-14-1xe7qte.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=429&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/424964/original/file-20211006-14-1xe7qte.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=539&fit=crop&dpr=1 754w, https://images.theconversation.com/files/424964/original/file-20211006-14-1xe7qte.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=539&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/424964/original/file-20211006-14-1xe7qte.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=539&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">We are using earphones more and more each year, but listening for how long is too long?</span>
<span class="attribution"><span class="source">Christian Moro / Author Provided</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-how-do-scabs-form-151586">Curious Kids: how do scabs form?</a>
</strong>
</em>
</p>
<hr>
<h2>How earphones might affect this system</h2>
<p>The ear is self-cleaning and best performs its function without interruption. However, anything that blocks the normal progression of earwax moving outside can cause issues. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/425368/original/file-20211008-17-13724qc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Man holds model of ear" src="https://images.theconversation.com/files/425368/original/file-20211008-17-13724qc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/425368/original/file-20211008-17-13724qc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/425368/original/file-20211008-17-13724qc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/425368/original/file-20211008-17-13724qc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/425368/original/file-20211008-17-13724qc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/425368/original/file-20211008-17-13724qc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/425368/original/file-20211008-17-13724qc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The outer ear, where wax is produced, extends inside the body.</span>
<span class="attribution"><a class="source" href="https://image.shutterstock.com/image-photo/man-holding-model-human-inner-260nw-1349291441.jpg">Shutterstock</a></span>
</figcaption>
</figure>
<p>Normal use of in-ear devices <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4704552/">don’t often</a> cause a problem. But prolonged earphone use, such as if you leave them in all day, could:</p>
<ul>
<li> compress the earwax, making it less fluid and harder for the body to naturally <a href="https://pubmed.ncbi.nlm.nih.gov/30277727/">expel</a></li>
<li> compact the earwax to the extent the body induces inflammation. This results in white blood cells migrating to the area, increasing the number of cells in the <a href="https://www.aafp.org/afp/2007/0515/p1523.html">blockage</a></li>
<li> impact air flow and stop wet earwax drying out. When earwax retains its stickiness for prolonged periods of time, it encourages build-up</li>
<li> trap sweat and moisture in the ears, making them more prone to bacterial and fungal <a href="https://journals.lww.com/thehearingjournal/fulltext/2010/03000/how_to_care_for_moist_ears.12.aspx">infections</a></li>
<li> create a barrier to the earwax’s natural expulsion, which ends up stimulating the secretory glands and increasing <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4311346/">earwax production</a></li>
<li> reduce overall ear hygeine, if the pads of the earbuds are not cleaned properly, or <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8335768/">contaminated</a> with bacteria or infectious agents</li>
<li>damage your <a href="https://www.abc.net.au/news/2018-06-06/headphones-could-be-causing-permanent-hearing-damage/9826294">hearing</a> if the volume is set too high.</li>
</ul>
<p>If the build-up accumulates, excessive earwax can cause <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4356173/">hearing problems</a>, along with other symptoms such as pain, dizziness, tinnitus, itching, and vertigo. </p>
<p>If you need to listen for a prolonged period of time, using over-ear headphones may help a little. These offer a small amount of <a href="https://www.wellandgood.com/do-headphones-increase-ear-wax/">extra airflow</a> compared to the in-ear earphones and earbuds. However, this is not as good as leaving the ears open to the outside air, and an accumulation of earwax can still occur.</p>
<p>As they sit outside the ear canal, over-ear headphones are also less likely to cause any earwax compaction, or introduce bacteria or pathogens to the ear canal. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-is-it-bad-to-regularly-sleep-wearing-earplugs-60374">Health Check: is it bad to regularly sleep wearing earplugs?</a>
</strong>
</em>
</p>
<hr>
<h2>Nothing smaller than your elbow</h2>
<p>In most cases, the best way to control earwax is to <a href="https://www.scientificamerican.com/article/the-dangers-of-excessive-earwax/">leave it alone</a>. It is not recommended to use cotton buds frequently, as this can force earwax back into the ear canal. The longstanding <a href="https://www.ncbi.nlm.nih.gov/books/NBK2333/">advice</a> is not to put anything smaller than your elbow in your ear – in other words, don’t put anything in there! </p>
<p>Some traditional methods, such as olive oil drops or ear candles, may also have adverse effects and are not helpful.</p>
<p>If your have ear wax or related hearing concerns, your family doctor will have a range of treatment options to assist, and can also direct you to the correct health service if it requires longer-term management. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/425367/original/file-20211008-17-3xq6pq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="ear exam" src="https://images.theconversation.com/files/425367/original/file-20211008-17-3xq6pq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/425367/original/file-20211008-17-3xq6pq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/425367/original/file-20211008-17-3xq6pq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/425367/original/file-20211008-17-3xq6pq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/425367/original/file-20211008-17-3xq6pq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/425367/original/file-20211008-17-3xq6pq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/425367/original/file-20211008-17-3xq6pq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An otoscope helps visualise any wax build up in the ear.</span>
<span class="attribution"><a class="source" href="https://image.shutterstock.com/image-photo/closeup-female-doctor-examining-patients-260nw-1678999573.jpg">Shutterstock</a></span>
</figcaption>
</figure>
<p>Initially, they will look into your ear with a special instrument (otoscope) and see the extent of any blockage or <a href="https://www.mayoclinic.org/diseases-conditions/earwax-blockage/diagnosis-treatment/drc-20353007">dysfunction</a>.</p>
<p>In the meantime, the ear has a wonderful process of self-cleaning, and we should do our best to let this occur naturally. In most cases earphones are fine, but it might still be helpful to stay aware of how long you spend wearing them. Finally, be sure to always keep the volume at safe levels.</p><img src="https://counter.theconversation.com/content/168742/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Wireless earphones have freed us from devices. It’s tempting to wear them all day for phone calls, podcasts and music but research into hearing aids suggests this can create a sticky problem.Charlotte Phelps, PhD Student, Bond UniversityChristian Moro, Associate Professor of Science & Medicine, Bond UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1583762021-05-17T12:26:53Z2021-05-17T12:26:53ZWhy do we hate the sound of our own voices?<figure><img src="https://images.theconversation.com/files/400587/original/file-20210513-13-4ejtyv.jpg?ixlib=rb-1.1.0&rect=3%2C71%2C2476%2C1804&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Your voice, when played back to you, can sound unrecognizable.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/engraving-of-scary-woman-monster-with-three-royalty-free-illustration/988105126?adppopup=true">GeorgePeters/Getty Images</a></span></figcaption></figure><p><a href="http://scholar.google.com/citations?user=zZY5ezsAAAAJ&hl=en">As a surgeon who specializes in treating patients with voice problems</a>, I routinely record my patients speaking. For me, these recordings are incredibly valuable. They allow me to track slight changes in their voices from visit to visit, and it helps confirm whether surgery or voice therapy led to improvements.</p>
<p>Yet I’m surprised by how difficult these sessions can be for my patients. Many become visibly uncomfortable upon hearing their voice played back to them. </p>
<p>“Do I really sound like that?” they wonder, wincing. </p>
<p>(Yes, you do.) </p>
<p>Some become so unsettled they refuse outright to listen to the recording – much less go over the subtle changes I want to highlight. </p>
<p><a href="https://doi.org/10.1111/j.1365-2273.2005.01022.x">The discomfort we have over hearing our voices in audio recordings</a> is probably due to a mix of physiology and psychology.</p>
<p>For one, the sound from an audio recording is transmitted differently to your brain than the sound generated when you speak. </p>
<p>When listening to a recording of your voice, the sound travels through the air and into your ears – what’s referred to as “<a href="https://doi.org/10.1016/B978-0-12-385157-4.00121-4">air conduction</a>.” The sound energy vibrates the ear drum and small ear bones. These bones then transmit the sound vibrations to the cochlea, which stimulates nerve axons that send the auditory signal to the brain.</p>
<p>However, when you speak, the sound from your voice reaches the inner ear in a different way. While some of the sound is transmitted through air conduction, much of the sound is <a href="https://doi.org/10.1159/000266070">internally conducted directly through your skull bones</a>. When you hear your own voice when you speak, it’s due to a blend of both external and internal conduction, and internal bone conduction appears to boost the lower frequencies. </p>
<p>For this reason, people generally perceive their voice as deeper and richer when they speak. The recorded voice, in comparison, can sound thinner and higher pitched, which many find cringeworthy.</p>
<p>There’s a second reason hearing a recording of your voice can be so disconcerting. It really is a new voice – one that exposes a difference between your self-perception and reality. <a href="https://www.npr.org/2019/07/15/741827437/finding-your-voice-how-the-way-we-sound-shapes-our-identities">Because your voice is unique and an important component of self-identity</a>, this mismatch can be jarring. Suddenly you realize other people have been hearing something else all along.</p>
<p>Even though we may actually sound more like our recorded voice to others, I think the reason so many of us squirm upon hearing it is not that the recorded voice is necessarily worse than our perceived voice. Instead, we’re simply more used to hearing ourselves sound a certain way. </p>
<p>[<em>Get the best of The Conversation, every weekend.</em> <a href="https://theconversation.com/us/newsletters/weekly-highlights-61?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=weeklybest">Sign up for our weekly newsletter</a>.]</p>
<p><a href="https://doi.org/10.1111/j.1365-2273.2005.01022.x">A study published in 2005</a> had patients with voice problems rate their own voices when presented with recordings of them. They also had clinicians rate the voices. The researchers found that patients, across the board, tended to more negatively rate the quality of their recorded voice compared with the objective assessments of clinicians. </p>
<p>So if the voice in your head castigates the voice coming out of a recording device, it’s probably your inner critic overreacting – and you’re judging yourself a bit too harshly.</p><img src="https://counter.theconversation.com/content/158376/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Neel Bhatt does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>If you’ve ever cringed after hearing a recording of yourself, you’re not alone.Neel Bhatt, Assistant Professor of Otolaryngology, UW Medicine, University of WashingtonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1601522021-05-06T18:12:42Z2021-05-06T18:12:42ZNocturnal dinosaurs: Night vision and superb hearing in a small theropod suggest it was a moonlight predator<figure><img src="https://images.theconversation.com/files/398999/original/file-20210505-17-16fmhv4.png?ixlib=rb-1.1.0&rect=32%2C9%2C1511%2C788&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Fossils of _Shuvuuia deserti_ depict a small predatory creature with exceptional night vision and hearing.</span> <span class="attribution"><span class="source">Mick Ellison/American Natural History Museum</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Today, barn owls, bats, leopards and many other animals rely on their keen senses to live and hunt under the dim light of stars. These <a href="https://doi.org/10.1086/702250">nighttime specialists avoid the competition of daylight hours</a>, hunting their prey under the cloak of darkness, often using a combination of night vision and acute hearing.</p>
<p>But was there nightlife 100 million years ago? In a world without owls or leopards, were dinosaurs working the night shift? If so, what senses did they use to find food and avoid predators in the darkness? To better understand the senses of the dinosaur ancestors of birds, <a href="https://scholar.google.com/citations?user=kHIW_0cAAAAJ&hl=en&oi=ao">our team</a> of <a href="https://scholar.google.com/citations?user=6qODxwoAAAAJ&hl=en&oi=ao">paleontologists</a> and <a href="https://scholar.google.com/citations?user=m_p_Lc0AAAAJ&hl=en&oi=ao">paleobiologists</a> scoured research papers and museum collections looking for fossils that preserved delicate eye and ear structures. And we found some. </p>
<p>Using scans of fossilized dinosaur skulls, in a paper <a href="https://science.sciencemag.org/content/372/6542/610?intcmp=trendmd-sci">published in the journal Science on May 6, 2021</a>, we describe the most convincing evidence to date for nocturnal dinosaurs. Two fossil species – <em>Haplocheirus sollers</em> and <em>Shuvuuia deserti</em> – likely had extremely good night vision. But our work also shows that <em>S. deserti</em> also had incredibly sensitive hearing similar to modern-day owls. This is the first time these two traits have been found in the same fossil, suggesting that this small, desert-dwelling dinosaur that lived in ancient Mongolia was probably a specialized night-hunter of insects and small mammals.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/399011/original/file-20210505-23-hnil4h.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An artistic reconstruction showing _S. deserti as a small, feathered bipedal dinosaur with an owlish face." src="https://images.theconversation.com/files/399011/original/file-20210505-23-hnil4h.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/399011/original/file-20210505-23-hnil4h.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=848&fit=crop&dpr=1 600w, https://images.theconversation.com/files/399011/original/file-20210505-23-hnil4h.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=848&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/399011/original/file-20210505-23-hnil4h.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=848&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/399011/original/file-20210505-23-hnil4h.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1066&fit=crop&dpr=1 754w, https://images.theconversation.com/files/399011/original/file-20210505-23-hnil4h.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1066&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/399011/original/file-20210505-23-hnil4h.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1066&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"><em>Shuvuuia deserti</em> had acute hearing and low-light vision that would have allowed it to hunt at night.</span>
<span class="attribution"><span class="source">Viktor Radermaker</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Looking to theropods</h2>
<p>By studying fossilized eye bones, one of us, Lars Schmitz, had previously found that some small predatory dinosaurs <a href="https://doi.org/10.1126/science.1200043">may have hunted at night</a>. Most of these potentially nocturnal hunters were theropods, the group of three-toed dinosaurs that includes <em>Tyrannosaurus rex</em> and modern birds. But to date, fossils for only <a href="https://doi.org/10.1126/science.1200043">12 theropod species included the eye structures</a> that can tell paleontologists about night vision.</p>
<p>Our team identified four more species of theropods with clues for their sense of vision – for a total of 16. We then looked for fossils that preserve the structures of the inner ear and found 17 species. Excitingly, for four species, we were able to get measurements for both eyes and ears.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/399012/original/file-20210505-23-usv75o.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A close up photo of the skull of _S. deserti_ showing a large eye socket." src="https://images.theconversation.com/files/399012/original/file-20210505-23-usv75o.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/399012/original/file-20210505-23-usv75o.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=378&fit=crop&dpr=1 600w, https://images.theconversation.com/files/399012/original/file-20210505-23-usv75o.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=378&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/399012/original/file-20210505-23-usv75o.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=378&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/399012/original/file-20210505-23-usv75o.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=475&fit=crop&dpr=1 754w, https://images.theconversation.com/files/399012/original/file-20210505-23-usv75o.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=475&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/399012/original/file-20210505-23-usv75o.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=475&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The eye socket – and specifically the sclerical ring – of <em>S. deserti</em> shows an eye with a very large pupil capable of letting in large amounts of light.</span>
<span class="attribution"><span class="source">Mick Ellison/American Museum of Natural History</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Eye bones built for night vision</h2>
<p>Scleral ossicles are thin, rectangular bone plates that form a <a href="https://doi.org/10.1002/ar.24043">ring-like structure surrounding the pupils</a> of lizards as well as birds and their ancestors – dinosaurs. Scleral rings define the largest possible size of an animal’s pupil and can tell you how well that animal <a href="https://doi.org/10.1016/j.visres.2010.03.009">can see at night</a>. The larger the pupil compared to the size of the eye, the better a dinosaur could see in the dark.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/399017/original/file-20210505-19-1imtqg9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An owl skull with a cone like ring attached to the eye socket." src="https://images.theconversation.com/files/399017/original/file-20210505-19-1imtqg9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/399017/original/file-20210505-19-1imtqg9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=456&fit=crop&dpr=1 600w, https://images.theconversation.com/files/399017/original/file-20210505-19-1imtqg9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=456&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/399017/original/file-20210505-19-1imtqg9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=456&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/399017/original/file-20210505-19-1imtqg9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=573&fit=crop&dpr=1 754w, https://images.theconversation.com/files/399017/original/file-20210505-19-1imtqg9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=573&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/399017/original/file-20210505-19-1imtqg9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=573&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This owl skull clearly shows the large scleral ring that helps animals see in darkness.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Bubo_virginianus_8zz.jpg#/media/File:Bubo_virginianus_8zz.jpg">David J. Stang/WikimediaCommons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Since the individual bony ossicles of these rings fell apart after these animals died more than 60 million years ago, our team made scans of the fossils and then digitally reconstructed the eyes. Of all the theropods we examined, <em>H. sollers</em> and <em>S. deserti</em> had some of the proportionally largest pupils.</p>
<p><em>S. deserti</em>‘s pupil made up more than half of its eye, very similar to night-vision specialists that live today like geckos and nightjars. Our team then compared the fossils to 55 living species of lizards and 367 species of birds with known day or night activity patterns. According to the statistical analyses our team performed, there is a very high chance – higher than 90% – that <em>H. sollers</em> and <em>S. deserti</em> were nocturnal.</p>
<p>But those were not the only two theropods our team looked at. Our analysis also found a few other likely nighttime specialists – such as <em>Megapnosaurus kayentakatae</em> – as well as daylight specialists like <em>Almas ukhaa</em>. But we also found some species – like <em>Velociraptor mongoliensis</em> – with eyesight seemingly adapted for medium light levels. This might suggest that they hunted around dawn or dusk.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/399020/original/file-20210505-19-62si2q.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two white plastic molds on a black background both with an elongated vertical base splitting into a 'y' shape at the top." src="https://images.theconversation.com/files/399020/original/file-20210505-19-62si2q.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/399020/original/file-20210505-19-62si2q.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/399020/original/file-20210505-19-62si2q.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/399020/original/file-20210505-19-62si2q.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/399020/original/file-20210505-19-62si2q.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/399020/original/file-20210505-19-62si2q.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/399020/original/file-20210505-19-62si2q.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Molds of the inner ear canal from a barn owl (left) and <em>S. deserti</em> (right) are almost identical, suggesting that the small dinosaur had incredible hearing.</span>
<span class="attribution"><span class="source">Shivan Parusnath/Wits University</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Incredible ears of a dinosaur</h2>
<p>In today’s nocturnal animals, <a href="https://doi.org/10.1002/bies.201600006">hearing can be as important as keen eyesight</a>. To figure out how well these extinct dinosaurs could hear, we scanned the skulls of 17 fossil theropods to decipher the structure of their inner ears and then compared our scans to the ears of modern animals.</p>
<p>All vertebrates have a tube-like canal called the cochlea deep in their inner ear. Studies of living mammals and birds show that the longer this canal, the <a href="https://doi.org/10.1098/rspb.2008.1390">wider the range of frequencies an animal can hear</a> and the better they can hear <a href="https://doi.org/10.1098/rspb.2008.1390">very faint sounds</a>.</p>
<p>Our scans showed that <em>S. deserti</em> had an extremely elongated inner ear canal for its size – also similar to that of the living barn owl and proportionally much longer than all of the other 88 living bird species we analyzed for comparison. Based on our measurements, among dinosaurs, we found that predators had generally better hearing than herbivores. Several predators – including <em>V. mongoliensis</em> – also had moderately elongated inner ears, but none rivaled <em>S. deserti</em>’s. </p>
<h2>The life of a nocturnal dinosaur</h2>
<p>By studying the sensory abilities of dinosaurs, paleontologists like us not only are learning what species roamed the night, but can also begin to infer how these dinosaurs lived and shared resources.</p>
<p><a href="https://doi.org/10.1126/science.abe7941"><em>S. deserti</em> had extreme night vision and sensitive hearing</a>, and this little dinosaur probably used its incredible senses to hunt prey at night. It could likely hear and follow rustling from a distance before visually detecting its prey and digging it up from the ground with its short single-clawed arms. In the dry, desert-like habitats of millions of years ago, it might have been an evolutionary advantage to be active in the cooler temperatures of the night. </p>
<p>But according to our analysis, <em>S. deserti</em> wasn’t the only dinosaur active at night. Other dinosaurs like <em>V. mongoliensis</em> and the plant-eating <em>Protoceratops mongoliensis</em> both lived in the same habitat and had some level of night vision.</p>
<p>Paleontologists currently do not know the full suite of animals that shared <em>S. deserti</em>’s extreme nocturnal lifestyle in the ancient deserts of Mongolia – it is rare to find fossils with the right bones intact that allow paleontologists to investigate their senses. However, the presence of a specialized night forager highlights that much like today, some dinosaurs avoided the dangers and competition of daylight hours and roamed under the stars.</p>
<p>[<em>Get the best of The Conversation, every weekend.</em> <a href="https://theconversation.com/us/newsletters/weekly-highlights-61?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=weeklybest">Sign up for our weekly newsletter</a>.]</p><img src="https://counter.theconversation.com/content/160152/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jonah Choiniere receives funding from the National Research Foundation of South Africa. </span></em></p><p class="fine-print"><em><span>Roger Benson receives funding from the European Research Council, National Environments Research Council and Leverhulme Trust. </span></em></p><p class="fine-print"><em><span>Lars Schmitz does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>By looking at the eye bones and ear canals of extinct dinosaurs, researchers show that a small ancient predator likely hunted at night and had senses as good as a modern barn owl.Lars Schmitz, Associate Professor of Biology, Scripps CollegeJonah Choiniere, Professor of Dinosaur Paleontology, University of the WitwatersrandRoger Benson, Professor of Palaeobiology, University of OxfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1495982020-11-06T14:27:57Z2020-11-06T14:27:57ZThe coronavirus pandemic has worsened tinnitus for many sufferers – new research<figure><img src="https://images.theconversation.com/files/367940/original/file-20201106-19-88tkwa.jpg?ixlib=rb-1.1.0&rect=15%2C0%2C5077%2C3397&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Around 40% of people with pre-existing tinnitus experienced a worsening of symptoms after contracting COVID-19.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-vector/woman-covering-her-ears-hands-suffering-1395928190">Elena Abrazhevich/ Shutterstock</a></span></figcaption></figure><p>We learn more about the effects of COVID-19 on our health every day. We now know that contracting the coronavirus SARS-COV-2 can have a long-term impact on our <a href="https://theconversation.com/coronavirus-severe-forms-of-the-disease-can-damage-the-heart-136352">heart</a> and <a href="https://theconversation.com/coronavirus-can-cause-lasting-lung-damage-but-the-effects-may-ease-over-time-140398">lungs</a>, and the infection can even <a href="https://www.bbc.co.uk/news/health-54622059">persist for months</a> in some people. </p>
<p>We are now also seeing reports that COVID-19 is producing hearing-related symptoms, such <a href="https://link.springer.com/article/10.1007/s00405-020-06440-7">dizziness</a>, vertigo and <a href="https://casereports.bmj.com/content/13/11/e238419">hearing loss</a>. Our recent study has also found that the pandemic has <a href="https://www.frontiersin.org/articles/10.3389/fpubh.2020.592878/full">worsened tinnitus</a> for many individuals. </p>
<p><a href="https://www.nhsinform.scot/illnesses-and-conditions/ears-nose-and-throat/tinnitus">Tinnitus</a> is characterised by hearing unwanted sounds, such as a ringing or buzzing in your ears, without a corresponding external sound. It’s one of the most <a href="https://www.tinnitus.org.uk/all-about-tinnitus">frequently occurring</a> chronic conditions, affecting 12%–30% of the adult population worldwide. Although tinnitus occurs in all age groups, it’s more common in older adults. </p>
<p><a href="https://www.hearinglink.org/your-hearing/tinnitus/what-is-tinnitus/?gclid=CjwKCAiA4o79BRBvEiwAjteoYFeZa2FPgWnQibmEG--jXIaVtuvvMc--to2iPabkWgRvbLil5jRfWxoCt7YQAvD_BwE">Numerous factors</a> – including hearing loss, ear infections, exposure to loud noise and head injuries – are known to be associated with developing tinnitus. It can also be <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0127578">made worse</a> by certain noises, poor sleep, allergies or infections.</p>
<p>People with tinnitus are found to be at higher risk of lower emotional wellbeing, <a href="https://journals.sagepub.com/doi/pdf/10.1177/0194599819835178">depression</a> and <a href="https://www.sciencedirect.com/science/article/pii/S027273581730034X">anxiety</a>, possibly because of people’s frustration with their inability to escape or control the condition. Tinnitus may also make it difficult to sleep and concentrate, which can <a href="https://journals.sagepub.com/doi/full/10.1177/2331216520918416">affect daytime functioning</a>. </p>
<p>This led our team to realise that people with tinnitus might be experiencing increased levels of the condition as a result of the added stress and anxiety brought on by the pandemic. As such, we decided to perform an exploratory study to examine <a href="https://www.frontiersin.org/articles/10.3389/fpubh.2020.592878/full">changes in tinnitus</a> during the pandemic. </p>
<h2>Getting worse</h2>
<p>We surveyed a total of 3,103 people with tinnitus from 48 countries, almost half of whom were from the US and Canada. Although the survey was aimed at those with pre-existing tinnitus, seven respondents reported that having COVID-19 led to tinnitus, and four reported it led to hearing loss. These symptoms remained despite recovering from the virus, confirming what <a href="https://www.manchester.ac.uk/discover/news/hearing-deterioration-reported-by-discharged-covid-19-patients/">other studies have reported</a>.</p>
<p>Of the respondents, 237 reported experiencing COVID-19 symptoms, and 26 had tested positive for the virus. Of those reporting symptoms, 40% said their pre-existing tinnitus worsened as a result. </p>
<p>Those who took medication (such as paracetamol or tyenol) to alleviate coronavirus symptoms reported a significant increase in the presence of their tinnitus. <a href="https://www.tinnitus.org.uk/drugs">Certain medications</a> (such as aspirin and some antibiotics) are known to have an adverse effect on hearing and tinnitus, so closely monitoring hospitalised patients will be important. </p>
<p>Of the respondents who had not had COVID-19, 67% reported their tinnitus stayed the same during the pandemic, worsened for 32%, and improved for 1% of respondents. Females and younger adults (under the age of 50 years) found tinnitus significantly more bothersome during the pandemic. </p>
<p>The respondents in these groups explained that these changes might partly be caused by changes in employment and increased childcare and household responsibilities during the pandemic. This may be associated with possible exposure to more noise (such as toys, or DIY tools) or higher <a href="https://www.tinnitus.org.uk/tinnitus-and-stress">levels of stress</a> which often aggravates tinnitus.</p>
<figure class="align-center ">
<img alt="Young mother holding child as she tries to speak on the phone while working from home." src="https://images.theconversation.com/files/367935/original/file-20201106-19-1vkodky.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/367935/original/file-20201106-19-1vkodky.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/367935/original/file-20201106-19-1vkodky.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/367935/original/file-20201106-19-1vkodky.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/367935/original/file-20201106-19-1vkodky.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/367935/original/file-20201106-19-1vkodky.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/367935/original/file-20201106-19-1vkodky.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Increased childcare responsibilities might be one reason tinnitus worsened for women.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/young-beautiful-businesswoman-talking-on-mobile-1405812413">ErsinTekkol/ Shutterstock</a></span>
</figcaption>
</figure>
<p>Other factors found to have worsened participants’ tinnitus during the pandemic included health-related concerns, social distancing measures, lifestyle changes, and reduced exercise levels. Health-related concerns included worrying about contracting the virus and not been able to receive healthcare for other conditions during the pandemic. </p>
<p>Respondents reported that the pandemic made it more difficult to do activities that helped distract them from their tinnitus – such as going to an exercise class. It was also harder for them to relax due to the constant worry, which aggravated their tinnitus. Loneliness as a result of fewer social interactions, self-isolation and poor sleep also significantly worsened tinnitus. </p>
<p>Healthcare support for tinnitus was not always readily available during the pandemic, and the lockdown restrictions also limited social support and contributed to <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0239698">feelings of loneliness</a>. Lack of support may also have contributed to worsening tinnitus due to people feeling unable to deal with the condition alone.</p>
<p>Respondents also reported that higher levels of depression, anxiety, irritability, and financial worries also contributed significantly to tinnitus being more bothersome during the pandemic. This finding highlights the complex two-way interaction that exists between tinnitus and emotional distress. They can trigger or worsen each other, and tinnitus frequently spikes or begins during stressful periods.</p>
<p>Due to the influx of reports of tinnitus and hearing loss associated with contracting COVID-19, there’s a need for further research in this area. In theory, COVID-19 could cause problems with parts of the auditory system. </p>
<p>Viral infections, including the Herpes viruses, rubella, cytomegalovirus, measles and mumps are all known to affect the <a href="https://www.soundscouts.com/au/blog/viruses-and-hearing-loss/">hearing</a> and/or <a href="https://www.cedars-sinai.org/health-library/diseases-and-conditions/l/labyrinthitis.html">balance system</a> – and this could be the same with SARS-COV-2. However, more research is needed to identify whether there’s a link between COVID-19, tinnitus and hearing loss, and the mechanisms behind this possible association.</p>
<p>For those who have developed tinnitus or experienced a worsening of it during the pandemic, medical services, <a href="https://www.tinnitus.org.uk/spike-in-your-tinnitus-during-covid-19">helplines, and online support groups</a> can help. <a href="https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD012614.pub2/full">Cognitive behavioural therapy</a> and <a href="https://www.frontiersin.org/articles/10.3389/fneur.2019.01135/full">mindfulness</a> may also help people better manage tinnitus.</p><img src="https://counter.theconversation.com/content/149598/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Eldre Beukes receives funding from the National Institute on Deafness and Communication Disorders of the National Institute of Health.She is a Postdoctoral Research Fellow, and affiliated with Lamar University, USA and Anglia Ruskin University, UK.
</span></em></p>Higher levels of stress was just one of the reasons the hearing problem may have worsened for many people.Eldre Beukes, Postdoctoral Fellow in Audiology, Anglia Ruskin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1419962020-07-07T13:05:43Z2020-07-07T13:05:43ZHow studying fruit flies might help us prevent age-related hearing loss in humans<figure><img src="https://images.theconversation.com/files/346012/original/file-20200707-46-rpronp.jpg?ixlib=rb-1.1.0&rect=15%2C0%2C3479%2C2325&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Around one in three people over 65 is affected by hearing loss.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/hearing-aid-on-women-ear-455434894">Vova Shevchuk/ Shutterstock</a></span></figcaption></figure><p>Hearing loss is a common age-related ailment, affecting nearly <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5482333/pdf/f1000research-6-12205.pdf">one in every three people</a> over the age of 65. The World Health Organization expects that by 2050, more than 900 million people will suffer from <a href="https://www.who.int/news-room/fact-sheets/detail/deafness-and-hearing-loss">disabling hearing loss</a>. But the causes of age-related hearing loss remain largely unknown, and there are no preventative treatments or cures. Alarmingly, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5527366/">recent studies</a> have even found links between age-related <a href="https://www.sciencedirect.com/science/article/pii/S037851221830118X?via%3Dihub">hearing loss and dementia</a>.</p>
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<p>We still don’t know why age-related hearing loss occurs, and why our hearing systems stay healthy up until decline begins to occur. But humans aren’t alone in their suffering. In fact, even fruit flies are prone to age-related hearing loss. Not only are fruit flies (<em>Drosophilia</em>) one of the most genetically accessible, and most versatile insect models researchers can use, many of their molecular pathways of hearing (and deafness) are very similar to those found in humans. This is why we used fruit flies as a models to explore why hearing loss happens in humans.</p>
<p>We were surprised to find that fruit flies actually maintain their sensitive hearing until very late in life. The average fruit fly lives for around 58 days. They maintain their sensitive hearing for around 50 days – about 85% of their life. This shows us that fruit flies are a prime model not only for studying human age-related hearing loss, but also for uncovering how we can maintain hearing function.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/346015/original/file-20200707-38-b3wxgw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/346015/original/file-20200707-38-b3wxgw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/346015/original/file-20200707-38-b3wxgw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/346015/original/file-20200707-38-b3wxgw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/346015/original/file-20200707-38-b3wxgw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/346015/original/file-20200707-38-b3wxgw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/346015/original/file-20200707-38-b3wxgw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Fruit flies are also prone to hearing loss.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/vial-containing-fruit-flies-fly-drosophila-1024284793">Sundry Photography/ Shutterstock</a></span>
</figcaption>
</figure>
<p>We used a <a href="https://www.nature.com/articles/s41598-020-64498-z">variety of different techniques</a> to explore the networks of <a href="https://www.nature.com/scitable/definition/transcription-factor-167/#:%7E:text=Transcription%20factors%20are%20proteins%20involved,regulate%20the%20transcription%20of%20genes.">transcription factors</a> in fruit flies. Transcription factors are the “master genes” that regulate other genes and orchestrate key signalling pathways that preserve healthy hearing during the fly’s life.</p>
<p>We identified four genes that are key in maintaining good hearing. These four genes exist in both flies and humans. These genes are known to be important for forming new nerve cells in the body, but we have now shown they’re linked to helping maintain hearing and likely other senses, too. </p>
<p>Just as there are many internal, physical, and chemical processes that lead to ear development, there are also distinct processes in the body dedicated entirely to ear maintenance. Specifically, we found that there are copies (paralogs) of known developmental genes – not the developmental genes themselves – which seemed to play the major roles in maintaining hearing function.</p>
<p>During evolution, genes can duplicate. The two resulting copies are called paralogs. Paralogs often diverge functionally, with one (or both) of them assuming new roles. In the case of the fully formed fruit fly ear, we found that one key development gene was instead replaced by its paralog after the fly’s ear had fully formed.</p>
<p>This might be a fundamental mechanism in evolution. The 19th century <a href="https://www.jstor.org/stable/pdf/3037718.pdf?refreqid=excelsior%3Afb365ec81838c2991471edc278a857e6">recapitulation theory</a> proposed that an organism’s developmental history re-enacts its evolutionary history. One might propose that an organ’s maintenance process is partly just a repeat of what it was designed to do during development. So, in order to keep our ears young, we might partially repeat its development – but this time the paralogs of the developmental genes carry out the job. </p>
<p>Knowing this will be important for future gene-therapeutic interventions to restore hearing in humans, which so far have largely concentrated on the master development gene of the human ear, <a href="https://www.tandfonline.com/doi/full/10.1517/14712598.2015.1009889">known as AT0H1</a>. In analogy to our findings, one could suggest that ATOH1’s paralogs (ATOH7 or NEUROD1) might be as good (or potentially better) targets when it comes to extending auditory health. The reason for this is that the original developmental master gene, <em>atonal</em>, is no longer active in the ears of adult flies, but its paralog, <em>amos</em>, is. So, instead of trying to repeat the developmental history or rebuild the ear “from scratch” it might be easier to boost the maintenance processes that are currently ongoing. </p>
<p>Indeed, we found that manipulating these paralogs in fruit flies could protect their ears from various aspects of age-related hearing loss. Fruit flies whose paralogs had been altered had hearing capabilities similar to young fruit flies. This suggests similar gene therapies in humans could provide a few more years of good auditory health.</p>
<p>Our study suggests that it might not even be necessary to understand age-related hearing loss to find new ways of preventing or treating it. By knowing which genes helped fruit flies maintain their hearing, we were able to then manipulate them to prevent age-related hearing loss. Identifying these genes in humans could stop hearing loss, too. In the end, the most pragmatic approach to fighting all forms of age-related decline might not be defeating it entirely – but rather, finding out how to make our hearing live as long as we do.</p><img src="https://counter.theconversation.com/content/141996/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Joerg T Albert receives funding from the Biotechnology and Biological Sciences Research Council, BBSRC (BB/M008533/1 and BB/R000549/1) and from the European Research Council, ERC under the Horizon 2020 research and innovation programme (Grant agreement Nos 648709 and 862216) and from Action on Hearing Loss, UK (grant S34). </span></em></p>Fruit flies, just like humans, are prone to age-related hearing loss.Joerg T Albert, Professor of Sensory Biology & Biophysics, UCLLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1399592020-06-08T19:49:12Z2020-06-08T19:49:12ZCurious Kids: How far away can dogs smell and hear?<figure><img src="https://images.theconversation.com/files/339941/original/file-20200604-67387-1bkz2ni.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Martin Valigursky Shutterstock</span> </figcaption></figure><blockquote>
<p><strong>How far away can dogs smell and hear? Georgina, age 8, Warrawee, New South Wales.</strong></p>
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<p><a href="https://theconversation.com/au/topics/curious-kids-36782"><img src="https://images.theconversation.com/files/291898/original/file-20190911-190031-enlxbk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=90&fit=crop&dpr=1" width="100%"></a></p>
<p>Great question Georgina. We know and learn about the world around us through our senses. The senses of smell and hearing in dogs mean they experience a different world to us. </p>
<p>Dogs have many more <a href="https://www.frontiersin.org/articles/10.3389/fvets.2018.00056/full" title="When the Nose Doesn’t Know: Canine Olfactory Function Associated With Health, Management, and Potential Links to Microbiota">smell receptors than humans</a> – a <a href="https://www.britannica.com/science/olfactory-receptor">receptor</a> is a part of the nose that recognises each unique smell particle.</p>
<p>Dogs also have a lot more surface area in their noses and are better at moving air through their noses than us. Watch a dog sniffing and you can see this for yourself. If more air passes through their nose they have more chance to pick up smells.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/339400/original/file-20200603-130923-5dk2ax.jpg?ixlib=rb-1.1.0&rect=104%2C85%2C3949%2C2818&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/339400/original/file-20200603-130923-5dk2ax.jpg?ixlib=rb-1.1.0&rect=104%2C85%2C3949%2C2818&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/339400/original/file-20200603-130923-5dk2ax.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/339400/original/file-20200603-130923-5dk2ax.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/339400/original/file-20200603-130923-5dk2ax.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/339400/original/file-20200603-130923-5dk2ax.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/339400/original/file-20200603-130923-5dk2ax.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/339400/original/file-20200603-130923-5dk2ax.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Dogs have a much better sense of smell than us.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/emayoh/3098990110/">Flickr/Redfishingboat (Mick O)</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
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</figure>
<p>How far dogs can smell depends on many things, such as the wind and the type of scent. Under perfect conditions, they have been <a href="https://www.goodreads.com/book/show/17368247-the-perfect-dog" title="The Perfect Dog by Roger Mugford">reported</a> to smell objects or people as far as 20km away.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-why-might-you-wake-up-without-a-voice-132592">Curious Kids: why might you wake up without a voice?</a>
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</em>
</p>
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<p>You might be interested to know dogs are not the only great smellers. The scientific family dogs belong to is Carnivora. This includes cats, bears and skunks. </p>
<p>These animals have incredible senses of smell as well. Bears have some of the best senses of smell in the family. Polar bears can smell seals, which they hunt, from <a href="https://www.livescience.com/43673-weird-facts-about-polar-bears.html">more than 30km away</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/339966/original/file-20200605-176564-ablshk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/339966/original/file-20200605-176564-ablshk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/339966/original/file-20200605-176564-ablshk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=430&fit=crop&dpr=1 600w, https://images.theconversation.com/files/339966/original/file-20200605-176564-ablshk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=430&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/339966/original/file-20200605-176564-ablshk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=430&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/339966/original/file-20200605-176564-ablshk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=540&fit=crop&dpr=1 754w, https://images.theconversation.com/files/339966/original/file-20200605-176564-ablshk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=540&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/339966/original/file-20200605-176564-ablshk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=540&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">What’s that I can smell? Polar bears can detect a seal from 30km away.</span>
<span class="attribution"><span class="source">Incredible Arctic/Shutterstock</span></span>
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</figure>
<p>How would it feel if you knew just by smell when your best friend was in the next room, even if you couldn’t see them? Wouldn’t you love to know where your parents had hidden your favourite chocolate biscuits in the pantry, just by sniffing them out? </p>
<h2>Dog the detector</h2>
<p>This amazing sense of smell means dogs have some of the most interesting jobs of any animal: the detection dog. </p>
<p>Detection dogs help <a href="https://www.sarda.net.au/">search and rescue</a> organisations to find missing people, look for dangerous materials such as <a href="https://www.police.wa.gov.au/About-Us/Our-Agency/Specialist-Units/Mounted-and-Canine-Operations/Police-Dog-Squad">drugs and bombs</a>, <a href="https://www.abc.net.au/news/2017-06-10/afp-sniffer-dogs-training-explained/8606228">illegal imports</a> at airports, and help <a href="https://www.lfwseq.org.au/sniffing-solutions-detection-dogs-conservation/">find wild animals</a>. </p>
<p>All of it’s done with their noses, which makes dogs some of the best sniffers in the world.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/339969/original/file-20200605-176538-b87f5t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/339969/original/file-20200605-176538-b87f5t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/339969/original/file-20200605-176538-b87f5t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=409&fit=crop&dpr=1 600w, https://images.theconversation.com/files/339969/original/file-20200605-176538-b87f5t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=409&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/339969/original/file-20200605-176538-b87f5t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=409&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/339969/original/file-20200605-176538-b87f5t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=514&fit=crop&dpr=1 754w, https://images.theconversation.com/files/339969/original/file-20200605-176538-b87f5t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=514&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/339969/original/file-20200605-176538-b87f5t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=514&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sniff! He’s not admiring the colour of the suitcase.</span>
<span class="attribution"><span class="source">New Africa/Shutterstock</span></span>
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<p>Even pet dogs enjoy <a href="https://www.companionanimalpsychology.com/2020/04/beating-boredom-blues-sniffing-out-new.html">playing games using smell</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-why-is-our-dog-so-cute-138035">Curious Kids: Why is our dog so cute?</a>
</strong>
</em>
</p>
<hr>
<p>One thing that might still puzzle you is why, when dogs have such a great sense of smell, they like to smell things that are disgusting to us, like other dogs’ bottoms. That’s a story for another day. </p>
<h2>Hear and far</h2>
<p>Now we know dogs can smell lots of things from far away, what about their hearing? What can dogs hear, and from how far? To find out, first we have to talk about what dogs and all animals (including us) hear: sound frequencies.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/qNf9nzvnd1k?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">WARNING: Do not listen with headphones.</span></figcaption>
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<p>Sounds have waves. The frequency of sound is how close together the sound waves are. The closer together the waves, the higher the frequency or pitch. You can think of this like the beach during a storm, when waves hit the beach more often. </p>
<p>Dogs and people hear about the same at low frequencies of sound (around 20Hz). This changes at high frequencies of sound, where dogs hear up to 70-100kHz, much better than people at only 20kHz. Dogs hear sound frequencies at least three times as high compared to people.</p>
<p>You may have wondered how those special silent dog whistles work? They make high-frequency sounds that dogs can hear but we can’t. Because dogs can hear higher frequencies than us, there are a lot more sounds for dogs to hear.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/3eiiaTDLdjM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
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<p>They can also hear sounds that are softer or farther away, as far as a kilometre. That means dogs can be more sensitive to loud sounds. This is why <a href="https://positively.com/dog-behavior/behavior-problems/fears-and-phobias/noise-phobias/">some dogs are scared of fireworks or thunderstorms</a>. It is also why a dog might bark at a sound you cannot hear.</p>
<h2>Prick up your ears</h2>
<p>Part of how dogs hear so well has to do with their ear muscles. Dogs have more than a dozen muscles that allow them to tilt, lift and rotate each ear independently of one another.</p>
<p>This helps dogs locate where sounds come from. It is also part of why dogs may <a href="https://www.petmd.com/dog/behavior/why-do-dogs-tilt-their-heads">tilt their heads</a> to some sounds. Police who use dogs say the first sign their dog has located a suspect is when they see their ears move around to focus on a place.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/339972/original/file-20200605-176550-1fd9tgj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/339972/original/file-20200605-176550-1fd9tgj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/339972/original/file-20200605-176550-1fd9tgj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=368&fit=crop&dpr=1 600w, https://images.theconversation.com/files/339972/original/file-20200605-176550-1fd9tgj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=368&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/339972/original/file-20200605-176550-1fd9tgj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=368&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/339972/original/file-20200605-176550-1fd9tgj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=462&fit=crop&dpr=1 754w, https://images.theconversation.com/files/339972/original/file-20200605-176550-1fd9tgj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=462&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/339972/original/file-20200605-176550-1fd9tgj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=462&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Hear that? The police dog’s on to something.</span>
<span class="attribution"><span class="source">ChiccoDodiFC/Shutterstock</span></span>
</figcaption>
</figure>
<p>Having great hearing also helps dogs with another one of their interesting jobs: the assistance dog. <a href="https://guidedogsaustralia.com/">Assistance dogs</a> work with people who need help in their daily lives, such as those who are blind or deaf.</p>
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<p>
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Read more:
<a href="https://theconversation.com/why-dogs-dont-care-for-being-groomed-and-for-the-love-of-dog-dont-snip-their-whiskers-132656">Why dogs don’t care for being groomed (and for the love of dog don’t snip their whiskers)</a>
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</em>
</p>
<hr>
<p>Excellent hearing means dogs can identify people arriving at a home or oncoming traffic at a walkway. With such great hearing, dogs can help people in need navigate the world around them too! </p>
<p>Thinking about different senses is a great way to learn about all animals. What are their senses like? How does that help them think about the world differently to us? </p>
<p>This was a fantastic question, Georgina, and we hope you enjoyed these answers as much as we enjoyed answering them.</p>
<hr>
<p><em>Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskids@theconversation.edu.au">curiouskids@theconversation.edu.au</a></em></p>
<hr><img src="https://counter.theconversation.com/content/139959/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Susan Hazel is on the Dog and Cat Management Board of South Australia, and the Board for RSPCA South Australia.</span></em></p><p class="fine-print"><em><span>Eduardo J Fernandez does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Imagine being able to detect a smell from more than a kilometre away. Dogs can sniff out things from a greater distance than that.Susan Hazel, Senior Lecturer, School of Animal and Veterinary Science, University of AdelaideEduardo J Fernandez, Visiting Assistant Professor, Florida Institute of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1393922020-06-03T20:12:27Z2020-06-03T20:12:27ZAre your kids using headphones more during the pandemic? Here’s how to protect their ears<figure><img src="https://images.theconversation.com/files/339082/original/file-20200602-95028-2bh8sl.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C7360%2C4912&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>During the coronavirus pandemic, have your kids been using headphones more than usual? Maybe for remote schooling, video chats with relatives, or for their favourite music and Netflix shows?</p>
<p>We have to be careful about both the volume and duration of headphone use. Listening too loudly or for too long can do permanent damage to hearing. The good news is there are ways to prevent long-term harm relatively easily.</p>
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Read more:
<a href="https://theconversation.com/5-reasons-its-safe-for-kids-to-go-back-to-school-137064">5 reasons it's safe for kids to go back to school</a>
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<h2>Hearing loss in children may be increasing</h2>
<p>Our hearing needs to be protected throughout life, because damage to hearing cannot be reversed. This is why we have workplace noise exposure <a href="https://www.worksafe.vic.gov.au/noise-safety-basics">standards and guidelines</a>, which tell workers when to use protection such as earplugs or ear defenders.</p>
<p>Unfortunately though, hearing loss in children may be increasing. A <a href="https://pubmed.ncbi.nlm.nih.gov/30872125/?from_single_result=Prevalence+of+Childhood+Hearing+Loss+and+Secular+Trends%3A+A+Systematic+Review+and+Meta-Analysis&expanded_search_query=Prevalence+of+Childhood+Hearing+Loss+and+Secular+Trends%3A+A+Systematic+Review+and+Meta-Analysis">study</a> from last year, in which both of us were involved, reviewed the hearing of more than 3.3 million children from 39 countries across a 20-year period.</p>
<p>We found around 13% of children had measurable hearing loss by 18 years of age that may impact their ability to decipher sounds important for understanding speech. The study suggested hearing loss in kids is rising – but we don’t yet know why. </p>
<p>Not many studies have examined whether headphone use is directly linked to hearing loss in children. But in one <a href="https://jamanetwork.com/journals/jamaotolaryngology/article-abstract/2684510">study of 9-11-year-old Dutch children</a>, where 14% had measurable hearing loss, around 40% reported using portable music devices with headphones. Could headphones be contributing? Possibly, but unfortunately we don’t know for sure, and more studies are needed.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/339083/original/file-20200602-95054-ikzvos.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/339083/original/file-20200602-95054-ikzvos.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/339083/original/file-20200602-95054-ikzvos.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/339083/original/file-20200602-95054-ikzvos.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/339083/original/file-20200602-95054-ikzvos.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/339083/original/file-20200602-95054-ikzvos.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/339083/original/file-20200602-95054-ikzvos.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">More studies are needed to determine if headphone use is causing a decline in kids’ hearing. But there are ways to mitigate the risks regardless.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>How do we know whether our children’s hearing is being affected?</h2>
<p>Adults typically first notice a hearing problem by struggling to hear higher-pitched sounds clearly. Sounds may seem muffled, or the ears may feel “blocked”, or they may notice a ringing or buzzing sound, called tinnitus.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/even-mild-hearing-loss-as-a-child-can-have-long-term-effects-on-how-the-brain-processes-sound-125149">Even mild hearing loss as a child can have long-term effects on how the brain processes sound</a>
</strong>
</em>
</p>
<hr>
<p>Unlike adults, children won’t necessarily know how to describe these symptoms. Instead they may use terms they do know, like a bee buzzing, a whistle, or the wind blowing. Parents should treat any reported ear symptom as serious and get their child’s hearing tested. It’s best to visit a hearing clinic first, and then a GP if necessary, although this will depend on your location.</p>
<h2>Excessive noise damages hearing</h2>
<p>Our inner ear (cochlea) contains tiny hair cells, which change sounds we hear into electrical signals for our brain. These hair cells are finely tuned and are responsible for different pitches of sound, like keys on a piano. </p>
<p>Exposure to loud noise can damage these hair cells and perhaps the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2812055/">nerve</a> that connects the cochlea to the brain. Repeated excessive noise exposure can lead to permanent hearing loss. Unfortunately, by the time someone experiences hearing problems, some irreversible damage has already happened.</p>
<h2>What should we do to protect kids’ hearing?</h2>
<p>The risk of hearing damage depends on both loudness and duration of sound exposure. Limiting both helps to reduce the risk of hearing damage.</p>
<h3>Limiting loudness</h3>
<p>We measure the loudness of sound in decibels (dB). But it’s important to note that the dB scale is logarithmic rather than linear. That means a 110dB sound (similar to a chainsaw) is actually much more than 10% louder than a 100dB sound. Parents can download free sound meter apps that help with understanding the volume of different environments and activities.</p>
<p>A more difficult task for parents is monitoring the loudness within their children’s headphones. Some headphones leak sounds out, while others insulate the sound into the ear. So a child using “leaky” headphones at a safe volume may appear to be listening to sounds that are too loud, but a child with tightly sealed headphones could be playing sounds at potentially damaging levels without parents noticing.</p>
<p>To understand their child’s specific usage, parents can: </p>
<ul>
<li><p><strong>listen to their child’s headphones</strong> to understand how loud sounds can become</p></li>
<li><p>check to see if children can <strong>hear you talk at a normal volume from an arm’s length away</strong>, over the sounds playing on the headphones. If they can, their headphone use is more likely to be at a safe volume. </p></li>
</ul>
<p>There are headphones designed for children that limit the maximum loudness – usually to 85dB. While a limit is great, listening to 85dB sounds all day every day is not risk-free. </p>
<p>Noise-cancelling headphones are another option, albeit expensive. By reducing the intrusion of outside noise, it should mean children can keep headphone volume lower.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/339088/original/file-20200602-95049-xdpotw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/339088/original/file-20200602-95049-xdpotw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/339088/original/file-20200602-95049-xdpotw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/339088/original/file-20200602-95049-xdpotw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/339088/original/file-20200602-95049-xdpotw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/339088/original/file-20200602-95049-xdpotw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/339088/original/file-20200602-95049-xdpotw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Parents can limit the loudness of headphones, as well as the duration of time spent listening with headphones.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h3>Managing duration</h3>
<p>We should also monitor how long we’re exposed to sound. Everyday conversation is around 60dB, which will not be a problem regardless of the duration of exposure. However, <a href="http://dangerousdecibels.org/education/information-center/decibel-exposure-time-guidelines/">guidelines</a> say we can be exposed an 85dB sound (like a rubbish truck) for up to 8 hours at a time. But if the loudness of the sound is increased by just 3 decibels to 88dB, the sound energy is doubled, and safe exposure time would drop to just 4 hours. Operating a chainsaw at 110dB would then be limited to around 1 minute before damage is likely to occur.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/tinnitus-scale-of-hearing-damage-for-music-industry-workers-revealed-127373">Tinnitus: scale of hearing damage for music industry workers revealed</a>
</strong>
</em>
</p>
<hr>
<p>Exposure to noise is cumulative. Noise can also come from other sources in the child’s environment. Consider a child’s activities throughout a day. Parents should try to avoid consecutive noisy exercises, like headphone use, music practice, then noisy toys or games. Considering the total “doses” of sound in the day means parents should schedule some breaks to allow the ears time to recover.</p>
<p>Of course, parents should practise what they preach! Modelling responsible use of headphones and awareness of the enjoyment of being able to hear well into adulthood is key.</p>
<hr>
<p><em>This article is supported by the <a href="https://theconversation.com/au/partners/judith-neilson-institute">Judith Neilson Institute for Journalism and Ideas</a>.</em></p><img src="https://counter.theconversation.com/content/139392/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Peter Carew has previously received funding that originated from the NHMRC. </span></em></p><p class="fine-print"><em><span>Valerie Sung receives funding from the National Health and Medical Research Council, the L'Oreal-UNESCO For Women In Science Fellowship, the Garnett Passe and Rodney Williams Memorial Foundation, the Royal Children's Hospital Foundation, the University of Melbourne Stevenson Chair of Paediatrics Strategic Support, the Murdoch Children's Research Institute, and previously received funding from the Royal Australasian College of Physicians Cottrell Research Establishment Fellowship and the Equity Trustees Charitable Trusts.</span></em></p>Listening with the volume too high or for too long can cause permanent hearing loss, but there are ways we can minimise the risks.Peter Carew, Lecturer, The University of MelbourneValerie Sung, Paediatrician, Senior Research Fellow, Honorary Clinical Associate Professor, Murdoch Children's Research InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1361042020-04-30T12:11:03Z2020-04-30T12:11:03ZMasks and distancing make it tough for the hard-of-hearing, but here’s how to help<figure><img src="https://images.theconversation.com/files/331529/original/file-20200429-51466-k9kdm7.jpg?ixlib=rb-1.1.0&rect=8%2C35%2C5982%2C3952&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An already tough situation is made worse for those with hearing loss.
</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/doctors-home-visiting-during-the-quarantine-royalty-free-image/1215677043?adppopup=true">filadendron/Getty Images</a></span></figcaption></figure><p>The Centers for Disease Control and Prevention has recommended that all Americans wear <a href="https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/diy-cloth-face-coverings.html">face coverings</a> when in public. Hospitals across the country are assuming everyone who walks through the door is a potential COVID-19 case, so are requiring patients to wear a mask and come alone. </p>
<p>These changes pose potential communication problems for about <a href="https://doi.org/10.2105/AJPH.2016.303299">60 million Americans who are living with hearing loss</a>, ranging from mild trouble to severe loss or deafness in one or both ears. The vast majority of people with hearing loss have never had a hearing test and do not use hearing aids, especially <a href="https://doi.org/10.1177/0898264315585505">in populations affected by health disparities</a>. For example, only an estimated <a href="https://doi.org/10.1001/jamaoto.2019.0433">5% of Hispanic/Latino adults with hearing loss</a> use hearing aids.</p>
<p>Along with my audiology and public health colleagues from the <a href="http://lwhl.arizona.edu/h3-coalition">Hispanic Hearing Healthcare Access Coalition</a>, we strongly recommend that communities take special measures to stay connected with the hard-of-hearing at this time. Mask wearing and social distancing <a href="https://youtu.be/Lbdi9ndxNj8">present a real problem</a> for many people with hearing loss. </p>
<h2>Harder hearing</h2>
<p>Human brains are <a href="https://doi.org/10.3389/fnins.2014.00386">designed to use visual cues</a>, like watching one another’s lips move, <a href="https://doi.org/10.1037/pag0000094">to help understand speech</a>. Wearing a mask eliminates this vital visual information. </p>
<p>Acoustically, <a href="https://www.hearingreview.com/hearing-loss/health-wellness/how-do-medical-masks-degrade-speech-reception">face masks muffle speech</a>. Donning a mask over a hearing aid or cochlear implant can be problematic or uncomfortable – causing some to remove their hearing devices. </p>
<p>The need to stay at least six feet apart for <a href="https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/social-distancing.html">social distancing</a> can also make hearing and understanding speech more difficult. As distance increases, sound levels decrease. Research shows that moving farther away <a href="https://doi.org/10.1121/1.4976191">makes it more challenging for people with hearing loss</a> to focus their attention on understanding speech. </p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/331532/original/file-20200429-51513-1t3a070.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/331532/original/file-20200429-51513-1t3a070.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/331532/original/file-20200429-51513-1t3a070.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/331532/original/file-20200429-51513-1t3a070.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/331532/original/file-20200429-51513-1t3a070.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/331532/original/file-20200429-51513-1t3a070.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/331532/original/file-20200429-51513-1t3a070.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/331532/original/file-20200429-51513-1t3a070.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">People cannot rely on pre-pandemic habits to compensate, like leaning in to get closer, seeing a person speaking, or bringing a loved one to the hospital to help.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/woman-putting-hand-to-her-ear-royalty-free-image/79122325">Image Source/Getty Images</a></span>
</figcaption>
</figure>
<p>Research shows <a href="https://doi.org/10.1002/nur.21540">background noise in a hospital makes it difficult to hear, understand and absorb key information</a>, with memory disrupted even if what was said in the moment was heard. After measuring sound levels in a Portland, Oregon Veterans hospital, researchers recorded background noise from medical and surgical wards then tested acutely ill patients. In the best-case scenario with low noise, hospitalized patients with mild to moderate hearing loss could recall only 58% of key words. This dropped to 30% recall at the highest levels of hospital noise tested. All these disruptions can have serious consequences.</p>
<p>People with hidden or <a href="https://doi.org/10.1002/lary.28604">undiagnosed hearing loss</a> may now be revealed, as their coping strategies falter. In this new reality, those who are hard-of-hearing and deaf may be unable to access public health recommendations, learn about available services or make informed decisions about their own care when speech is only auditory. This is especially true for people in hospitals, nursing homes or quarantine, who may find themselves suddenly isolated without assistance from family or friends. </p>
<h2>Enhancing communication</h2>
<p>The good news is that simple, effective strategies can boost communication during this time of wearing masks and beyond. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/330763/original/file-20200427-145566-9o0oe6.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/330763/original/file-20200427-145566-9o0oe6.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/330763/original/file-20200427-145566-9o0oe6.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/330763/original/file-20200427-145566-9o0oe6.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/330763/original/file-20200427-145566-9o0oe6.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/330763/original/file-20200427-145566-9o0oe6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/330763/original/file-20200427-145566-9o0oe6.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/330763/original/file-20200427-145566-9o0oe6.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Laura Coco, Au.D., a Ph.D. candidate at the University of Arizona, demonstrates the use of teleaudiology to connect remotely with someone with a cochlear implant.</span>
<span class="attribution"><span class="source">Laura Coco, Au.D.</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Face each other at a safe distance of at least six feet. Maintaining eye contact enhances social connection and keeps attention focused on communication. Speak more slowly and with care to make it easier for listeners. Speakers often <a href="https://doi.org/10.1121/1.2784148">naturally try to compensate by projecting</a>, but a more effective approach is <a href="https://doi.org/10.3766/jaaa.16.3.4">to speak more clearly, with greater enunciation</a>.</p>
<p>Ask others to repeat back what you said to confirm the message is being understood and not just heard. For health care providers, this <a href="https://www.ahrq.gov/patient-safety/reports/engage/teachback.html">“teach-back” strategy</a> is essential to ensure understanding, whether the discussion is in-person <a href="https://doi.org/10.1371/journal.pone.0206473">or remote</a>. </p>
<p>Real-time captioning can improve <a href="https://www.nad.org/2020/04/17/telehealth-during-coronavirus/">communication access in telehealth</a>, <a href="https://www.deafhhtech.org/rerc/accessible-virtual-meeting-tips/">virtual meetings</a> and <a href="https://theconversation.com/how-to-help-students-with-a-hearing-impairment-as-courses-move-online-134582">online education</a>.</p>
<p><a href="https://pubmed.ncbi.nlm.nih.gov/26161525/">Ask the deaf or hard-of-hearing</a> person, “How can I best communicate with you?” Try <a href="https://doi.org/10.1044/jshr.3404.921">re-phrasing the information</a> if the listener is having difficulty understanding your message. Write your message down or try speech-to-text if someone is having trouble hearing you.</p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/330765/original/file-20200427-145544-1iha2gn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/330765/original/file-20200427-145544-1iha2gn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/330765/original/file-20200427-145544-1iha2gn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/330765/original/file-20200427-145544-1iha2gn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/330765/original/file-20200427-145544-1iha2gn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/330765/original/file-20200427-145544-1iha2gn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/330765/original/file-20200427-145544-1iha2gn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/330765/original/file-20200427-145544-1iha2gn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Bryan Wong, Au.D., an audiologist and Ph.D. student at the University of Arizona, makes face shields for local Tucson hospitals.</span>
<span class="attribution"><span class="source">Bryan Wong, Au.D.</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Select quiet spaces with little background noise for improved listening. If available, use or make clear masks or <a href="http://3dprint.nih.gov/discover/face-shield">face shields</a>, which will help by <a href="https://doi.org/10.3766/jaaa.15151">restoring visual information</a> in speech.</p>
<p>Seek out and offer multiple forms of communication, such as written text or real-time captioning and assistive technology. For those who use American Sign Language, qualified interpreters can be accessed through video relay. People with <a href="https://www.acdhh.org/media/1846/dhh-covid-19-communication-cards.pdf">hearing loss</a> or <a href="https://www.acdhh.org/media/1844/db_cvhl-covid-19-communication-cards.pdf">combined hearing and vision loss</a> may want to bring a printed communication card along with them to the hospital. The <a href="https://www.hearingloss.org/coronavirus-covid-19-resources/">Hearing Loss Association of America</a> and <a href="https://www.nad.org/coronavirus/">National Association of the Deaf</a> are sharing guidance for patients and providers. </p>
<p>Following these recommendations can empower people to communicate more effectively with the hard-of-hearing. While many things are out of control at this time, everyone can choose communication strategies that will help each other.</p>
<p>[<em>You need to understand the coronavirus pandemic, and we can help.</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=upper-coronavirus-help">Read The Conversation’s newsletter</a>.]</p><img src="https://counter.theconversation.com/content/136104/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nicole Marrone receives funding from a Patient-Centered Outcomes Research Institute® (PCORI®) Eugene Washington PCORI Engagement Award (EA-15629-UOA), the National Institute on Deafness and Other Communication Disorders (NIDCD) of the National Institutes of Health (R33DC015062), and the Arizona Community Foundation. </span></em></p>Audiologists recommend enhanced communication strategies in the time of coronavirus to help the nearly 60 million Americans living with hearing loss in one or both ears.Nicole Marrone, Associate Professor in Speech, Language, and Hearing Sciences, University of ArizonaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1363212020-04-27T12:12:08Z2020-04-27T12:12:08ZWelcome to your sensory revolution, thanks to the pandemic<figure><img src="https://images.theconversation.com/files/330391/original/file-20200424-163062-1amz996.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">No smell, no touch: People line up in Prague, Czech Republic, to get tested for the coronavirus. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/people-line-up-to-get-tested-for-the-coronavirus-in-prague-news-photo/1210703825?adppopup=true">Getty/Gabriel Kuchta</a></span></figcaption></figure><p>The way we see, hear, taste, touch and smell may never be the same again.</p>
<p>Courtesy of COVID-19, we are undergoing a sensory revolution. All of the senses have been affected by the coronavirus pandemic – not because the senses themselves have changed, but because the context and environment in which we sense has been profoundly altered.</p>
<p>Sensory historians <a href="https://www.sc.edu/study/colleges_schools/artsandsciences/history/our_people/directory/smith_m_mark.php">like myself</a>, who study the ways in which people in the past used their senses to understand and navigate their worlds, find that sensory shifts and perceptions tended to happen very slowly, measured in decades and centuries, <a href="https://www.bloomsbury.com/uk/sensory-history-9781845204150/">not in mere weeks and months</a>.</p>
<p>The shift that is happening now is unprecedented.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/jwClyd2lHWo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Emptiness is the symbol of life in the time of coronavirus.</span></figcaption>
</figure>
<h2>Sensory hierarchy</h2>
<p>The very idea that there are only five distinct senses took ages to mature, gaining credence in the Enlightenment. This period not only discounted erstwhile senses – such as the sense of “intuition” – but arranged the five senses into a distinctive hierarchy.</p>
<p>The Age of Reason empowered the eye as the sense of truth; seeing was believing, said most thinkers in the 1700s. Sight was followed by hearing, understood as more refined than the so-called lower or proximate senses. Those are smell, taste and touch, senses that had once been held in high esteem in the ancient and medieval worlds, but which lost their currency and <a href="https://www.bloomsbury.com/uk/sensory-history-9781845204150/">became more associated with the animal senses</a>.</p>
<p>These changes took time. Seeing was believing by about 1800, but it had taken centuries for the original iteration of the phrase, “seeing is believing, but feeling’s the truth,” to lose its tactile component.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/330397/original/file-20200424-163058-ezgub5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/330397/original/file-20200424-163058-ezgub5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/330397/original/file-20200424-163058-ezgub5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/330397/original/file-20200424-163058-ezgub5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/330397/original/file-20200424-163058-ezgub5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/330397/original/file-20200424-163058-ezgub5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/330397/original/file-20200424-163058-ezgub5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/330397/original/file-20200424-163058-ezgub5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The sight, sound and smell of traffic have disappeared from New York City.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/the-view-looking-east-down-an-empty-street-amid-the-news-photo/1220494566?adppopup=true">Getty/Alexi Rosenfeld</a></span>
</figcaption>
</figure>
<h2>Sensing changes</h2>
<p>With the sensory hierarchy intact, the 19th century ushered in some profound and long-term changes in how people used and understood their senses.</p>
<p>Olfaction offers a good example. Western noses became more refined, more sensitive and more alert to noxious smells. Rank and fetid smells gave way to a world that valued pleasant and deodorized smells. Washing and bathing became more popular, as did the use of perfumes and scents. Noses that could detect the difference were applauded. This olfactory <a href="https://www.google.com/books/edition/The_Foul_and_the_Fragrant/LI1M4sLcvPAC?hl=en&gbpv=1&dq=alain+corbin+fould+and+the+fragrant&printsec=frontcover">evolution in smells and habits of smelling took about a century</a>. </p>
<p>Now think of the sensory changes that have taken place in just a matter of months.</p>
<h2>New sights, louder sounds</h2>
<p>Once-trusty eyes betray us in the face of an invisible enemy. Seeing is no longer believing. Those who appear perfectly healthy <a href="https://www.npr.org/sections/goatsandsoda/2020/04/13/831883560/can-a-coronavirus-patient-who-isnt-showing-symptoms-infect-others">may be unknowing disease transmitters</a>.</p>
<p>But if the cause of COVID-19 is invisible, its effects are emphatically not. Desolate city streets are new sights; the absence of airplane contrails strikes many as almost primordial; masks render <a href="https://www.youtube.com/watch?v=jwClyd2lHWo">once-familiar faces unrecognizable</a>. </p>
<p>Soundscapes have changed, as have habits of listening. <a href="https://www.bloomberg.com/news/articles/2020-04-22/how-silent-spreaders-make-coronavirus-hard-to-beat-quicktake">Coronavirus spreaders are sometimes described as “silent.</a>” Many urban dwellers hear less traffic and formerly smothered sounds – <a href="https://www.nbcwashington.com/news/coronavirus/hopeful-birdsong-foreboding-sirens-a-pandemic-in-sound/2265854/">such as birdsong</a> – now can be heard. </p>
<p>The world is in some ways a much quieter place. Seismic sensors are picking up activity that used to be drowned out <a href="https://gizmodo.com/seismometers-worldwide-detect-decrease-in-human-activit-1842526497">by the activity of cities</a>. None of these sounds is new, but the effects of COVID-19 have reconfigured habits of listening and thresholds of hearing. Human voices are louder because there are <a href="https://www.irishtimes.com/news/ireland/irish-news/coronavirus-birdsong-seems-louder-and-the-ravens-are-more-relaxed-1.4231725">no whispers at six feet</a>.</p>
<p>The sense of smell has been hit hard. To breathe, after all, is to smell – if you can. Anosmia – the loss of the sense of smell – <a href="https://scopeblog.stanford.edu/2020/04/17/how-viruses-like-the-coronavirus-can-steal-our-sense-of-smell/">is an early sign of infection</a>. </p>
<p>Even if we keep our sense of smell, we now pause before inhaling, lest we <a href="https://economictimes.indiatimes.com/news/international/world-news/lost-sense-of-smell-may-be-peculiar-clue-to-coronavirus-infection/articleshow/74767666.cms">breathe in an enemy we cannot see</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/330399/original/file-20200424-163110-gh3c20.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/330399/original/file-20200424-163110-gh3c20.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/330399/original/file-20200424-163110-gh3c20.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/330399/original/file-20200424-163110-gh3c20.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/330399/original/file-20200424-163110-gh3c20.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/330399/original/file-20200424-163110-gh3c20.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/330399/original/file-20200424-163110-gh3c20.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/330399/original/file-20200424-163110-gh3c20.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Food tastes different if you can’t eat it until you get it home.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/woman-wearing-gloves-and-a-scarf-can-be-seen-in-the-news-photo/1219591346?adppopup=true">Getty/Alexi Rosenfeld</a></span>
</figcaption>
</figure>
<p>Taste is no longer as easily sated, and palates are rearranged. Restaurants still cater, but in takeout fashion and with less variety. Hot food once served in the restaurant is colder and less palatable after it’s transported to the more distant dining room table. Clammy hamburgers on soggy buns served with limp french fries, anyone? Grocery stores now ration once taken-for-granted staples, <a href="https://www.bloomberg.com/news/articles/2020-04-21/food-rationing-is-new-reality-for-buyers-once-spoiled-for-choice">notably eggs, milk and meat</a>.</p>
<p>Touch is the obvious sensory casualty in all of this. Centuries of handshaking habits have evaporated; high fives are gone. Outside of families, hugs, kisses and nuzzles have <a href="https://www.allure.com/story/covid-19-skin-hunger-lack-of-touch">all been lost with the fear of infection</a>.</p>
<h2>No guide</h2>
<p>In sensory terms, there has been nothing like this. </p>
<p>Even the violence done to the senses by wars, hurricanes, tornadoes and earthquakes is <a href="https://global.oup.com/academic/product/the-smell-of-battle-the-taste-of-siege-9780190658526?lang=en&cc=us;%20https://books.google.com/books/about/Camille_1969.html?id=CBcRmQEACAAJ">modest in scale and scope compared to this sensory revolution</a>. </p>
<p>Possible legacies, short-term or long, are hard to fathom. Beyond the deaths, the long-term effects of this pandemic will likely be in words and culture, not eternal lockdowns. Sensory and rhetorical turns of phrases will change. The results will not be even. Thanks to virtual communication, “See ya” and “I hear ya” should remain stable, but “staying in touch” and “getting a grip” could go the way of the sensory dinosaur.</p>
<p>But if normalcy eludes us? </p>
<p>A whole new world of sensory engagement will emerge, and it could be terrifying. Our soundscape could be civil strife, punctuated with the <a href="https://www.dailymail.co.uk/news/article-8235307/Riots-break-suburbs-Paris-amid-anger-French-police-heavy-handedness-lockdown.html">smell of tear gas</a> and the <a href="https://www.theguardian.com/world/2020/mar/28/south-africa-police-rubber-bullets-shoppers-covid-19-lockdown">resounding sting of rubber bullets on flesh</a>.</p>
<p>There is no sensory past that can guide us here. It is a genuine revolution of the senses. And it stinks.</p>
<p>[<em>Deep knowledge, daily.</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=deepknowledge">Sign up for The Conversation’s newsletter</a>.]</p><img src="https://counter.theconversation.com/content/136321/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mark M. Smith does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>All of the senses have been affected by the coronavirus pandemic, not because the senses have changed, but because the world has, writes a sensory historian.Mark M. Smith, Carolina Distinguished Professor of History, University of South CarolinaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1251492019-11-05T15:05:47Z2019-11-05T15:05:47ZEven mild hearing loss as a child can have long-term effects on how the brain processes sound<figure><img src="https://images.theconversation.com/files/297365/original/file-20191016-98670-1a607vj.jpg?ixlib=rb-1.1.0&rect=34%2C25%2C5716%2C3802&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/little-africanamerican-girl-hearing-problem-on-1007018965?src=KFdr11iccvaJcrnrOg8a7w-1-44">Africa Studio/ Shutterstock</a>, <span class="license">Author provided</span></span></figcaption></figure><p>When we are born, our brains have a lot to learn. For the newborn baby, everything they learn about the world around them comes from their senses. Therefore, if a child’s brain is deprived of sensory information, it will continue to develop, but in a different way.</p>
<p>A good example of this comes from children who are born deaf. Research has shown that adults who have been deaf since birth show changes in the way their brains process sensory information. Parts of the brain that would normally process sounds (the so-called auditory cortex) are also <a href="https://www.ncbi.nlm.nih.gov/pubmed/12960757">activated by visual stimuli</a>, for example.</p>
<p>However, we also know that timing is everything. If someone becomes deaf as an adult, their brains won’t suddenly change, if at all. But if a child is born deaf, early intervention is key. Such children would need to be fitted with cochlear implants <a href="https://www.ncbi.nlm.nih.gov/pubmed/12476090">within the first few years of life</a> if they wish to maximise their chances of being able to hear.</p>
<p>Until recently, scientists believed that these <a href="https://en.wikipedia.org/wiki/Critical_period">sensitive or critical periods</a> only applied in cases of severe sensory deprivation – for instance, in deaf children with little or no access to sounds. However, <a href="https://elifesciences.org/articles/46965">our research found</a> that even mild-to-moderate hearing loss in childhood was linked to changes in the way sounds are processed in the brain during adolescence.</p>
<p>In our study, we measured the brain responses of a group of children with <a href="https://www.actiononhearingloss.org.uk/hearing-health/hearing-loss-and-deafness/types-and-causes/">mild-to-moderate sensorineural hearing loss</a> while they were listening to sounds. Sensorineural hearing loss is a permanent hearing loss caused by damage to the inner ear, in this case <a href="https://www.nchearingloss.org/coch.htm#:%7E:text=The%20cochlea%20is%20the%20sense,your%20skull%20behind%20each%20ear.">the cochlea</a>. Those with “mild” hearing loss have a loss between 20-40 decibels – which typically makes it difficult to follow speech in noisy situations. Those with “moderate” hearing loss have a loss between 41-70 decibels, which makes it difficult to follow conversational speech without hearing aids. </p>
<p>The sounds they listened to varied, from simple non-speech sounds (such as a beep), to complex non-speech sounds (which sounded like speech, but without any distinguishable words or information). They also listened to speech sounds (complex both acoustically and linguistically). </p>
<p>We used a technique called electro-encephalography, or EEG, to measure the tiny amounts of electrical activity that happen in the brain in response to sounds. Because we know that <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2121131/">brain responses change during childhood</a>, even in those with normal hearing, we divided the children into 8-12 year-olds and 12-16 year-olds. We tested 46 children with hearing loss and 44 children with normal hearing, with roughly equal numbers in the younger and older groups. </p>
<p>We found several differences between the brain responses of children with hearing loss and those without hearing loss. But the most important finding related to a brain response that signals when the brain has detected a change in sounds. Whereas younger children with mild-to-moderate hearing loss showed relatively normal brain responses to a change in sounds, older children with hearing loss did not. In fact, on average, the brains of older children with hearing loss did not make these responses at all.</p>
<p>We didn’t believe the results at first, and thought that our findings might reflect historical differences between the younger test group and the older test group. For example, advances in medical screening and hearing aid technology may have differed between children born at an earlier point in time and those born later, resulting in better outcomes for the younger children. But to test whether our results were “real”, we needed to see what happened when the younger children got older.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/300227/original/file-20191105-88378-j8j6pb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/300227/original/file-20191105-88378-j8j6pb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/300227/original/file-20191105-88378-j8j6pb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/300227/original/file-20191105-88378-j8j6pb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/300227/original/file-20191105-88378-j8j6pb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/300227/original/file-20191105-88378-j8j6pb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/300227/original/file-20191105-88378-j8j6pb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">We initially thought the results might have been because of advances in hearing aid technology for the younger participants.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/otolaryngologist-putting-hearing-aid-little-boys-1070495471?src=e5b72f02-2135-4da0-898b-23276d2a01e2-2-59">Pixel-Shot/Shutterstock</a></span>
</figcaption>
</figure>
<p>We waited about six years before contacting the children with hearing loss who had been in the younger group (8-12 years old) during the initial study. These children were now between 13 and 17 years old, which was around the same age as the older group was in the first study. Of those we managed to contact, 13 agreed to come back to be retested. We used an identical test to that of six years earlier. </p>
<p>The results surprised us. Whereas, six years previously, the brains of these children had been able to detect a change in sounds, now these responses had either disappeared or grown smaller. It was as though their brains no longer “noticed” important differences between sounds – although these children could still discriminate differences, the responses indicating that the brain had detected a change had gone. The children’s level of hearing loss had remained the same as it was six years earlier. Therefore, our results suggested that changes were occurring in the brains of the children with hearing loss as they grew older.</p>
<h2>Earlier detection and better treatment</h2>
<p>Our findings raise a number of questions, both for science and for intervention. In our study, the sounds differed in loudness for children with hearing loss compared to those with no hearing loss. An important question to ask is whether we would find a similar pattern of results for normally hearing children, if we tested them using quieter sounds.</p>
<p>Assuming not, our findings may provide an explanation for the <a href="https://pubs.asha.org/doi/10.1044/2016_JSLHR-L-16-0297">higher-than-expected incidence of language difficulties</a> among children with hearing loss. An important next step will be to see if these brain changes are linked to language difficulties in these children, and if we can predict those at risk of future difficulties. </p>
<p>Since 2006, all babies born in the UK have been offered a newborn hearing screen within a few days of birth. However, mild hearing loss is not routinely screened for, so it isn’t detected in many of these children until later in childhood, if at all. Our research suggests that this may be too late. Also, while hearing aids do a good job at raising volume, they are currently unable to address many of the <a href="https://psyarxiv.com/h9x3p/">changes in sound quality</a> that children with hearing loss experience. It may therefore be that improvements in technology, combined with earlier intervention, will be key to stemming the brain changes associated with hearing loss in children before they occur.</p><img src="https://counter.theconversation.com/content/125149/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lorna Halliday receives funding from the Medical Research Council. </span></em></p><p class="fine-print"><em><span>Axelle Calcus receives funding from the H2020 Marie Skłodowska-Curie actions.</span></em></p>Children between 12 and 16 years old with mild-to-moderate hearing loss showed differences in their brain responses.Lorna Halliday, Principal Research Associate, University of CambridgeAxelle Calcus, Research fellow, École normale supérieure (ENS) – PSLLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1176482019-07-16T11:42:17Z2019-07-16T11:42:17ZDid we mishear Neil Armstrong’s famous first words on the Moon?<figure><img src="https://images.theconversation.com/files/284122/original/file-20190715-173329-zldb6u.png?ixlib=rb-1.1.0&rect=2%2C3%2C642%2C542&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">It's the case of the missing 'a.'</span> <span class="attribution"><a class="source" href="https://upload.wikimedia.org/wikipedia/commons/0/0d/Neil_Armstrong_pose.jpg">Nick Lehr/The Conversation via NASA</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>On July 20, 1969, <a href="https://www.nasa.gov/mission_pages/apollo/missions/apollo11.html">an estimated 650 million people</a> watched in suspense as Neil Armstrong descended a ladder towards the surface of the Moon. </p>
<p>As he took his first steps, he uttered words that would be written into history books for generations to come: “That’s one small step for man. One giant leap for mankind.” </p>
<p>Or at least that’s how the media reported his words. </p>
<p>But Armstrong <a href="https://www.telegraph.co.uk/news/science/space/9770712/Neil-Armstrongs-family-reveal-origins-of-one-small-step-line.html">insisted</a> that he actually said, “That’s one small step for <em>a</em> man.” In fact, in the official transcript of the Moon landing mission, <a href="https://www.hq.nasa.gov/alsj/a11/a11.step.html">NASA transcribes</a> the quote as “that’s one small step for (a) man.”</p>
<p><a href="https://scholar.google.com/citations?user=wi_55KAAAAAJ&hl=en">As a linguist</a>, I’m fascinated by mistakes between what people say and what people hear.</p>
<p>In fact, <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0155975">I recently conducted a study on ambiguous speech</a>, using Armstrong’s famous quote to try to figure out why and how we successfully understand speech most of the time, but also make the occasional mistake. </p>
<h2>Our extraordinary speech-processing abilities</h2>
<p>Despite confusion over Armstrong’s words, speakers and listeners have a remarkable ability to agree on what is said and what is heard. </p>
<p>When we talk, we formulate a thought, retrieve words from memory and move our mouths to produce sound. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3113495/">We do this quickly</a>, producing, in English, around five syllables every second.</p>
<p>The process for listeners is equally complex and speedy. We hear sounds, which we separate into speech and non-speech information, combine the speech sounds into words, and determine the meanings of these words. Again, this happens nearly instantaneously, and errors rarely occur. </p>
<p>These processes are even more extraordinary when you think more closely about the properties of speech. Unlike writing, speech doesn’t have spaces between words. When people speak, there are typically very few pauses within a sentence.</p>
<p>Yet listeners have little trouble determining word boundaries in real time. This is because there are little cues – like pitch and rhythm – that indicate when one word stops and the next begins. </p>
<p>But problems in speech perception can arise when those kinds of cues are missing, especially when pitch and rhythm are used for non-linguistic purposes, like in music. This is one reason why misheard song lyrics – called “<a href="https://www.isca-speech.org/archive_open/swap/swap_039.html">mondegreens</a>” – are common. When singing or rapping, a lot of the speech cues we usually use are shifted to accommodate the song’s beat, which can end up jamming our default perception process.</p>
<p>It’s not just lyrics that are misheard. It can happen in everyday speech, and some have wondered if this is what happened in the case of Neil Armstrong.</p>
<h2>Studying Armstrong’s mixed signals</h2>
<p>Over the years, researchers have tried to comb the audio files of Armstrong’s famous words, with mixed results. <a href="https://web.archive.org/web/20061004151135/http://www.cnn.com/2006/US/09/30/moon.quote.ap/index.html">Some have suggested</a> that Armstrong definitely produced the infamous “a,” <a href="http://itre.cis.upenn.edu/%7Emyl/languagelog/archives/003630.html">while others maintain</a> that it’s unlikely or too difficult to tell. But the original sound file was recorded 50 years ago, and the quality is pretty poor. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/qEM_h5WbFks?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The audio of Armstrong’s first words on the Moon at full speed and half speed.</span></figcaption>
</figure>
<p>So can we ever really know whether Neil Armstrong uttered that little “a”? </p>
<p>Perhaps not. <a href="https://doi.org/10.1371/journal.pone.0155975">But in a recent study</a>, my colleagues and I tried to get to the bottom of this. </p>
<p>First, we explored how similar the speech signals are when a speaker intends to say “for” or “for a.” That is, could a production of “for” be consistent with the sound waves, or acoustics, of “for a,” and vice-versa? </p>
<p>So we examined nearly 200 productions of “for” and 200 productions of “for a.” We found that the acoustics of the productions of each of these tokens were nearly identical. In other words, the sound waves produced by “He bought it for a school” and “He bought one for school” are strikingly similar.</p>
<p>But this doesn’t tell us what Armstrong actually said on that July day in 1969. So we wanted to see if listeners sometimes miss little words like “a” in contexts like Armstrong’s phrase.</p>
<p>We wondered whether “a” was always perceived by listeners, even when it was clearly produced. And we found that, <a href="https://doi.org/10.1177/0956797610384743">in several studies</a>, listeners often misheard short words, like “a.” This is especially true when the speaking rate was as slow as Armstrong’s.</p>
<p>In addition, we were able to manipulate whether or not people heard these short words just by altering the rate of speech. So perhaps this was a perfect storm of conditions for listeners to misperceive the intended meaning of this famous quote.</p>
<p>The case of the missing “a” is one example of the challenges in producing and understanding speech. Nonetheless, we typically perceive and produce speech quickly, easily and without conscious effort. </p>
<p>A better understanding of this process can be especially useful when trying to help people with speech or hearing impairments. And it allows researchers to better understand how these skills are learned by adults trying to acquire a new language, which can, in turn, help language learners develop more efficient strategies. </p>
<p>Fifty years ago, humanity was changed when Neil Armstrong took those first steps on the Moon. But he probably didn’t realize that his famous first words could also help us better understand how humans communicate.</p>
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<p class="fine-print"><em><span>Melissa Michaud Baese-Berk does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Armstrong always insisted that he said, ‘That’s one small step for a man.’ Yet everyone omits the ‘a’ when they repeat the quote. A linguist tries to get to the bottom of what happened.Melissa Michaud Baese-Berk, Associate Professor of Linguistics, University of OregonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1143402019-04-09T13:24:38Z2019-04-09T13:24:38ZWorkers in Tanzania’s noisy factories are at risk of hearing damage<figure><img src="https://images.theconversation.com/files/268129/original/file-20190408-2905-qms01u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Manufacturing sites are high noise working areas.</span> <span class="attribution"><span class="source"> Israel Paul Nyarubeli</span></span></figcaption></figure><p>Excessive exposure to noise can cause permanent hearing loss. It’s estimated that a <a href="https://www.who.int/health-topics/news-room/fact-sheets/detail/deafness-and-hearing-loss">third</a> of disabling hearing problems in the world are caused by excessive exposure to noise among adults who are older than 65. Some noise workplaces include mining, manufacturing, agriculture and construction sites.</p>
<p>The number of people with hearing loss in the world has <a href="https://www.who.int/news-room/fact-sheets/detail/deafness-and-hearing-loss">increased</a> over the past two decades, from <a href="https://www.ncbi.nlm.nih.gov/pubmed/12689363">120 million</a> people in 1995 to 466 million in 2018. Estimates of hearing loss caused by working in noisy environments are <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4007124/">higher</a> in low- and middle-income countries including sub-Saharan Africa than high-income countries. This may be due to ongoing economic investments in industrialisation as well as inadequate public health policies, lack of industrial regulation and limited resources spent on preventive measures. </p>
<p>Despite <a href="https://www.ncbi.nlm.nih.gov/pubmed/28685503">efforts</a> such as engineering and administrative controls, and mandating the use of hearing protection devices at workplaces by governments and health and research organisations, this problem isn’t going away.</p>
<p>People who work in really noisy places such as construction sites, military sites, mines and factories are particularly at an increased risk of hearing damage or loss.</p>
<p>We conducted a <a href="https://academic.oup.com/annweh/article/62/9/1109/5064905">study</a> looking at workers in high noise environments in Tanzania. We wanted to determine if these workers knew the effect of working in noisy environments and if they had access to noise protection devices. We found that most of the workers didn’t have any protection against potential hearing loss and didn’t know that the negative effects of working in a noisy environment were irreversible. This sort of <a href="https://apps.who.int/iris/bitstream/handle/10665/177884/WHO_NMH_NVI_15.2_eng.pdf">damage</a> affects the inner part of the human ear and can’t be effectively treated with existing technology. </p>
<p>Hearing loss like this is preventable. Measures to control or reduce workplace noise exposure are critical to protect the health and safety of these workers. </p>
<h2>What we found</h2>
<p>We surveyed workers in large steel manufacturing factories in Dar es Salaam, Tanzania. We asked if they knew that exposure to high noise levels might cause hearing problems. Only 45% of participants did. And only 33% understood that this damage was permanent. </p>
<p>We were shocked to find that workers in iron and steel factories were exposed to an average noise level of 92 decibels. This level is higher than the <a href="http://www.tbs.go.tz/index.php/standards/">national regulatory limit</a> for noise exposure at work, which is 85 decibels. This is similar to standing next to an operating jackhammer without hearing protection or standing next to a landing aircraft without protection for your ears. </p>
<p>Additionally, 86% of the factory workers we studied had never been provided with nor used hearing protection devices. This was unexpected in such large and well-organised factories.</p>
<p>We believe the situation is probably the same in factories in other low and middle income countries. It’s also likely to be worse in small and unorganised workplaces in many other countries in the world, among them places like <a href="https://www.ncbi.nlm.nih.gov/pubmed/19672017">India</a>.</p>
<h2>Tackling the problem</h2>
<p>Our research shows that many factory workers are exposed to hazardous noise levels and aren’t provided with hearing protection gear. </p>
<p>This situation calls for government and industry to promote and implement control measures in workplaces with high noise levels such as factories and construction sites. </p>
<p>Industry must provide workers with hearing protection devices. Government needs to ensure that operational safety guidelines are followed. And workers must learn about the dangers of noise exposure and received training on measure they can take to protect themselves. </p>
<p>This is important because deafness has biological, physical and psychological and economic <a href="https://www.who.int/health-topics/news-room/fact-sheets/detail/deafness-and-hearing-loss">effects</a> on individuals, families and societies. With the right protection and care, hearing loss in the workplace can be avoided.</p><img src="https://counter.theconversation.com/content/114340/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>This work is part of the PhD project ‘occupational noise exposure and hearing loss among factory workers in Tanzania’ led by Professors Bente E. Moen and Magne Bråtveit from Univesity of Bergen, Norway with close collaboration with Dr. Alexander M. Tungu (co supervisor) from Muhimbili University of Health and Allied Sciences (MUHAS), Dar es Salaam, Tanzania. The project was financially supported by the Norwegian State Educational Loan Fund (Lånekassen) and equipment provided by the Norwegian Programme for Capacity Development in Higher Education and Research for Development (NORHED). </span></em></p>Measures to control or reduce workplace noise exposure are critical to reducing hearing loss in workers.Israel Paul Nyarubeli, PhD candidate, University of BergenLicensed as Creative Commons – attribution, no derivatives.