The study shows the importance of seeking treatment early, according to Deryk Beal, Ph.D., executive director of the Institute for Stuttering Treatment and Research at the University of Alberta.
He notes that previous research used MRI scans to look at structural differences between the brains of adults who stutter and those who do not.
The problem with that approach is the scans come years after the onset of stuttering, which typically occurs between the ages of two and five, he said.
“You can never be quite sure whether the differences in brain structure or function you’re looking at were the result of a lifetime of coping with a speech disorder or whether those brain differences were there from the beginning,” explained Beal, a speech-language pathologist.
For his study, Beal scanned the brains of 28 children ranging from five to 12 years old. Half were diagnosed with stuttering; the other half served as a control.
Results showed that the inferior frontal gyrus region of the brain develops abnormally in children who stutter, the researcher reported.
This is important because that part of the brain is thought to control articulatory coding — taking information our brain understands about language and sounds and coding it into speech movements, he explains.
“If you think about the characteristics of stuttering — repetitions of the first sounds or syllables in a word, prolongation of sounds in a word — it’s easy to hypothesize that it’s a speech-motor-control problem,” he said.
Beal, who began his research at the University of Toronto and completed it at U of A, sees the results as a first step toward testing to see how grey matter volumes are influenced by stuttering treatment. It also should increase understanding about motor-sequence learning differences between children who stutter and those who do not, he notes.
“The more we know about motor learning in these kids, the more we can adjust our treatment — deliver it in a shorter period of time, deliver it more effectively,” he said.
The study was published in the journal Cortex.
Source: University of Alberta