Recent developments in stuttering

There is a growing trend to view stuttering from a medical perspective.

* Evidence that stuttering has a strong genetic component is persuasive to most researchers and to people who stutter PWS). The pair-wise concordance rate for stuttering at 60% is above the 50% rate for schizophrenia.

* The idea that hemispheric differences exist between PWS and those who don’t has been studied for many years using a variety of methods. Recent studies using brain imaging techniques such as PET scans have added specific evidence for these differences. Taken together these recent studies produce similar but not identical evidence that PWS have activation in the left primary speech motor areas or increased activation in similar areas in the right hemisphere.

* The basal ganglia seems to play an important role in many but probably not all PWS. Reduced efficiency in areas of the basal ganglia such as the caudate, putamin, and thalamus appear to interfere with important speech timing functions related to fluent speech. Excessive dopamine may contribute to this reduced function so some researchers have tried dopamine blocking medications to reduce stuttering. Such medications seem effective in more than half of the PWS who have participated in clinical trials.

Suggested Readings:

Alm, P.A. (2004). Stuttering and the basal ganglia circuits: A critical review of possible relations. Journal of Communication Disorders, 37, 325-369.

Curlee, R.F. & Siegel, G.M. (1997). Nature and treatment of stuttering (2nd ed.). Boston: Allyn and Bacon.

Riley, G., Maguire, G., Franklin, D., & Ortiz, T. (2001). Medical perspectives in the treatment of stuttering. Contemporary Issues in Communication Science and Disorders, 28, 104-110.