Physiological indices of speech and language processes: new windows on the onset of stuttering in young children
By Anne Smith
5th World Congress on Fluency Disorders, 2006

My colleague, Professor Christine Weber Fox and I have an ongoing project, 'physiological correlates of stuttering,' funded by the National Institutes of Health since 1988. Initially, our work focused on physiological aspects of stuttering in adults. We have reported many striking aspects of this disorder in adults, which I will turn to below. However, we know that stuttering typically starts in very young children. Therefore a major goal of our work over the years has been to adjust our experimental protocols, so that we may test very young children. Now, we are in the first year of collecting data on a longitudinal study of 4 and 5-year-old children who are stuttering and a cohort of non-stuttering children. We are hoping to have continued funding, so that we may track the development of these children until they are 10.

In July 2006 I presented our work to the International Fluency Association meeting in Dublin. In my talk I described how we view stuttering as a multifactorial disorder, and that a complete account of stuttering must incorporate motor, linguistic, cognitive, psychosocial, and genetic factors. However, everyone who stutters experiences breakdowns in speech motor control processes. Much of our work is focused on understanding why young children's speech motor systems become excessively vulnerable to a variety of demands. For example, we have found that adults who stutter show a decrease in motor coordination for speech when the linguistic demands of the utterance are increased. In addition, we have examined the activity of the brains of adults who stutter when they are not speaking at all, rather then when they are just reading sentences that sometimes contain mistakes. We have found that the response of the brain of adults who stutter to the errors shows a variety of anomalies compared to nonstuttering controls.

Clearly, we want to know if these characteristics of stuttering in adults are present at the onset of stuttering. Therefore in our current experiments we are recording speech movements while children produce words and sentences of increasing difficulty. In another experiment we record their brain waves while they watch an animated video of a young penguin, Pingoo, and his family. It sometimes contains mistakes, such as "Pingoo are naughty sometimes." We are in the initial phases of analyzing our data, but we are very hopeful that these experiments will help us to understand the factors that contribute to the onset of stuttering and aid us in predicting which children who are stuttering are likely to develop a chronic problem.

See also: Therapy leads in treatment of stammering - 5th World Congress on Fluency Disorders, 2006.

From the Winter 2006 issue of 'Speaking Out', page 13