Functional neuroimaging of cerebellar activation during single word reading and verb generation in stuttering and nonstuttering adults.

Articulatory discoordinations typically observed in fluent and disfluent speech of stuttering adults suggest an underlying deficiency in the precise timing needed for speech production. Positron emission tomography scans of stuttering adults showed generally higher cerebellar activations pre-treatment compared to nonstuttering control subjects. Intensive fluency treatment resulted in increased cerebellar activation during reading immediately post-treatment and a decrease to near normal levels at the 1 year follow scan. In contrast, verb generation resulted in a gradual but consistent decrease over the three scans. The results suggest that automaticity in motor and cognitive processes during speech production may need to be considered as an important factor in future investigations of stuttering.