New research from Australia suggests that stuttering is more common among preschoolers than first thought and refutes the idea that it is associated with developmental problems. If anything, the study, which followed 1600 children from birth to age 4, found the opposite: stuttering was tied to better language and non-verbal skills, and showed no discernible link with mental or emotional drawbacks.

The findings also support the idea that for many cases of preschool stuttering, “watch and wait” may be better than giving speech therapy straight away.

A paper on the research, led by Murdoch Childrens Research Institute, Victoria, was published online in the journal Pediatrics on Monday.

Nobody knows precisely what causes stuttering, which the National Stuttering Association (NSA) in the US defines as a communication disorder involving “disruptions or disfluencies” in a person’s speech.

Although the majority of affected children outgrow stuttering, it persists in about 1% of adults across all languages and cultures. The American Institute for Stuttering (AIS) suggests the condition affects nearly 4 million people in the US and 60 million worldwide.

The condition is not caused by emotional problems and is not a nervous disorder, but people who stutter often also have tension in their speech muscles, which can be compounded by shyness, anxiety and fear of speaking.

There are as many patterns of stuttering as people, and while some only have mild stuttering patterns, others can struggle with very severe forms. Curiously, many people who stutter can sing normally.

A survey the NSA conducted in 2009 found that speech therapy helps the majority of people who stutter, however, this new study suggests that for very young children, intervening too promptly after onset of stuttering may not be the best course of action.

Lead author Professor Sheena Reilly, who is also of the University of Melbourne Department of Paediatrics at the Royal Children’s Hospital in Melbourne, says their findings show that neither language ability, nor social and emotional development of young children who stutter is harmed by adopting a “watch and wait” approach, explaining that:

Current best practice recommends waiting for 12 months before commencing treatment, unless the child is distressed, there is parental concern, or the child becomes reluctant to communicate. It may be that for many children treatment could be deferred slightly further.”

For their study, the researchers set out to document “the natural history” of stuttering up to the age of four.

The data they analyzed came from the Early Language in Victoria Study, which kept records on 1619 children and their mothers from when the children were eight months to four years old.

The analysis showed that 11% of the children were stuttering by their fourth birthday. This is higher than previously reported figures: for instance the AIS says it occurs among 5-8% of children, usually between the ages of two and six.

But based on the data gathered from the parents, children who stuttered were no less socially or emotionally developed compared to non-stuttering peers. Plus, their scores on measures of vocabulary and other language skills were above the average.

Prof Reilly says while treatment is effective, it is intensive and expensive. To watch and wait would help target otherwise very scarce resources to the smaller number of youngsters who do not recover, and who do experience developmental problems.

There is also added security in the knowledge that delaying treatment for 12 months or a little longer does not reduce the effectiveness of treatment, she adds.

Surprisingly, the researchers also found that rates of recovery in the first 12 months after onset was low, it was only 6.3%. Recovery rates were higher in boys than girls, and in those children who did not repeat whole words at onset. Boys were also more likely to develop stuttering.

The low rates of recovery meant the researchers weren’t able to find out what factors predict which kids will recover. Prof Reilly says they will be working on this next.

Written by Catharine Paddock PhD