Persistence of stuttering into teenage years predicted by simple model

Wellcome Trust researchers have developed a model that can correctly predict whether a child will recover from a stutter in four out of five cases. The model should allow clinicians to target interventions at those children most in need of speech therapy.

The issue of stuttering has been brought to the public's attention recently thanks to the critically acclaimed film 'The King's Speech', which focuses on attempts by King George VI (played by Colin Firth) to overcome a severe stammer.

Stuttering - also known as stammering - is thought to affect one in twenty children under the age of five, with onset generally occurring around the age of three years old. More than two-thirds of these children will recover from their stuttering by their teenage years.

Around one in 50 children are still stuttering at eight years old, and half of these are likely to still be stuttering in their teenage years, but until now risk factors for predicting persistence or recovery for these older children have not been examined. This has made it difficult to target appropriate, cost-effective interventions at those children most in need.

The National Health Service provides speech and language therapy for free, but local health authorities work to a budget. In practice, children who stutter receive free treatment the first time they are referred but rarely receive further treatment via the NHS.

Professor Peter Howell and Dr Steve Davis from the Division of Psychology and Language Sciences UCL (University College London) used information obtained from 132 children who stuttered from the age of eight to their teenage years and examined which risk factors obtained at age eight most accurately predicted the persistence of a stutter. They then validated their findings on a separate group of 74 additional children who stuttered from the same age range.

Risk factors assessed at the beginning of the study were: head injury; age at stuttering onset; family history of stuttering; handedness; whether a second language was spoken in the home and, if so, when English was first learned; gender; and scores from the Stuttering Severity Instrument Version 3 (SSI-3, a standardised test involving measurement of speech symptoms, their durations and physical symptoms accompanying stuttering such as tics).

The researchers found that the only risk factor that reliably predicted the outcome in later years was the SSI-3 score. This predicted outcome in around four out of five cases.

Professor Howell explains: "Stuttering in children can cause unnecessary stress and affect their everyday interactions and social relationships. For some children, therapy is the best option to help them overcome the condition, but many authorities consider that it isn't necessary or indeed cost-effective to treat every child - many will recover naturally or have only minor stutters.

"By improving our ability to predict whether a child's stutter will persist, we can offer the most appropriate advice, whether it is to recommend treatment or 'watchful waiting'. Some therapists consider that it may even be advantageous to defer treatment for children whose stuttering does not cause concern for either child or parents."

The study is published in the 'Journal of Developmental & Behavioral Pediatrics'.