What did Moses, Marilyn Monroe, Winston Churchill, Claudius, Lewis Carroll and King George VI have in common?
They were all known to stutter.
A new study - by me and my collaborators around Australia and the UK and published yesterday in the American Journal of Pediatrics - has filled in some major gaps about the onset of stuttering: but like all good research projects, it has raised some interesting new questions about how stuttering progresses.
For example, we found children who stutter have better non-verbal skill development than non-stuttering children, but recovery from stuttering is much lower than previously thought.
Previous research
Stuttering is a speech disorder. It can manifest itself in different ways but is most commonly characterised by interruptions to speech such as hesitating, repeating sounds and words, or prolonging sounds.
While stuttering can be mild, in its most severe form it disrupts communication to such an extent that an individual may be unable to verbally communicate. The term “developmental stuttering” refers to stuttering commencing early in childhood.
Prior to our study there was limited knowledge about the natural history of stuttering, that is, how stuttering starts and progresses in young. Many children were reported to grow out of stuttering quite naturally - we wanted to know exactly how many did so in the first 12 months.
High rates of mental health problems - particularly social anxiety - are reported in adults who stutter, raising questions as to whether there might be signs of social, emotional and behaviour problems in young children.
Population-based research
Our study differed in methods and approach and reinforced the importance of population-based research. We recruited infants from the community well before stuttering onset whereas previously researchers recruited children:
when they presented for treatment (we know that clinic attendees are not representative of the population of children who stutter)
at three years of age (we illustrate that the majority of cases commence prior to three years) and these studies would have missed the majority of cases of early onset stuttering.
Our study was embedded within the Early Language in Victoria Study (ELVS) which recruited 1,910 infants aged around ten months. Annually, we collected information about the children’s speech and language development, general health and development, social, emotional and behavioural development and quality of life.
Some 1,619 parents agreed to participate in the stuttering study. Around the child’s second birthday we asked parents to tell us if they noticed their child stuttering. We then visited each child at home to verify the presence of stuttering and continued to do so each month for 12 months.
Not necessarily harmful
By four years of age 181 children had started to stutter (cumulative incidence 11.2%). This was more than twice the rate commonly reported (5%) in young children, and incidence rose steadily between two and 3.6 years of age, thereafter slowing noticeably.
We explored a range of factors hypothesised to be associated with stuttering onset (such as temperament, birth weight, maternal mental health, birth order) but jointly they explained very little variation in stuttering onset. Thus they could not be used to predict which children were more likely to stutter.
When we compared children who stuttered with their fluent peers at four years of age on measures of social, emotional and behavioural development we found no differences.
Parents did not report their stuttering children were more shy or withdrawn or more difficult to manage. Interestingly, stuttering children had higher scores than their non-stuttering counterparts on receptive and expressive language scores, non-verbal cognition and the social and pre-school dimensions of health-related quality of life.
Only nine children (6.3%) recovered in the first 12 months after onset.
What does this mean?
This study revealed three important new pieces of information:
Stuttering is much more common in young children than previously thought.
There was little evidence of harm to early mental health, temperament or psychosocial health related quality of life.
The children displayed better language and non-verbal skills than their non-stuttering counterparts.
Parents can thus be reassured that if their child starts to stutter that adverse affects are not the norm in the first year after onset.
These findings raise some important questions about what we should now do. The Lidcombe Program, a behavioural program which has been shown to be an effective treatment for pre-school stuttering, recommends waiting for 12 months after onset before commencing treatment.
One option is to step up services and treat all children who do not recover within 12 months. But with 11% of children stuttering, services could not meet the demand. Given so few children seem to recover in the first year should we wait longer - say for 18 months or even two years?
Our major challenges are to understand when the majority of children grow out of stuttering so as to help speech pathologists target the allocation of their scarce resources to the small number of children who do not resolve.
In the meantime “watchful waiting” for 12 months after onset is recommended unless the child is distressed, there is parental concern, or the child becomes reluctant to communicate.