Anne L. Foundas - US grants

Although stuttering occurs in 1 percent of the population and is a major source of both social and vocational disability, little is known of its biological basis. Improved understanding of the neural substrates of stuttering may aid in the development of treatment protocols. The major goal of this project is to study people who stutter in order to learn the relationship between behavioral asymmetries and anatomical brain asymmetries measured on volumetric MRI. The relationship of gender and degree of handedness to behavioral and neuroanatomic measures will also be investigated.

DESCRIPTION (provided by applicant): There is compelling new evidence that adults with persistent developmental stuttering (PDS) have anomalous anatomy in perisylvian speech, language, and motor areas on volumetric MRI, but these imaging methods have not been used to study children who do and do not stutter. Because of recent strong evidence that children with PDS are likely to be genetically different from children with transient developmental stuttering (TDS), it is important to study these two groups as it is unclear whether they are also biologically distinct in terms of brain morphology. The major aim of this project is to use in vivo volumetric MRI methods to study speech, language, and motor regions in children with PDS (n=30), children with TDS (n=30) and normally fluent children (n=30) matched for sex, handedness, age, and education. Regions of interest (R0ls) implicated by a model of stuttering positing an outer linguistic and an inner phonological-motor loop will be studied, including: (1) perisylvian speech-language areas (outer linguistic loop), and (2) cortical-subcortical motor areas (inner phonatory loop). It is hypothesized that asymmetry patterns of perisylvian and motor regions will be disrupted in children who stutter, and anomalous anatomy defined as altered volumes and disturbed gyral patterns may dissociate the children with TDS from those with PDS and from controls. It is unclear, however, whether the PDS group will have distinct anatomic features compared to the TDS group, or whether the PDS group will have more anatomic anomalies compared to the TDS group. Anatomical regions may deviate in concert, suggesting a severity effect, or specific regions may deviate independently, suggesting that multiple combinations result in stuttering. We will investigate whether specific regions are more likely to be atypical in severely dysfluent subjects, or whether specific configurations are associated with specific stuttering symptoms or with measures of speech motor control. We are also interested in whether there are distinct anatomical features within subgroups based on sex, and hand preference, because we found important differences in adults with PDS based on these variables. These proposed studies will provide a biological framework to learn more about brain morphology in children who do and do not stutter, provide information to develop targeted behavioral and pharmacological interventions, and may lead to earlier detection of children at risk for developmental stuttering.

risperidone; dopamine antagonists; neurophysiology; human therapy evaluation; neuroanatomy; stuttering; nervous system disorder chemotherapy; language; patient oriented research; human subject; functional magnetic resonance imaging; clinical research;

developmental disease /disorder; brain morphology; dyslexia; neuropsychology; cognition; reading; temporal lobe /cortex; parietal lobe /cortex; clinical research; magnetic resonance imaging; human subject; brain imaging /visualization /scanning; neuropsychological tests;