Differences in Speech Perception and Production Networks Between Persons who stutter and Controls

Previous research has demonstrated atypical lateralization and brain asymmetry in persons who stutter (PWS). It has also been demonstrated that PWS show atypical activation patterns when processing language stimuli. We wanted to investigate differences between PWS and controls in speech perception and production processing tasks. Dichotic listening (DL) and soundmorph fMRI paradigms were applied to obtain functional measures. In addition we investigated structural differences by using diffusion tensor imaging (DTI) and analysing our data with voxel-based morphometry (VBM). The results indicate that stuttering is related to abnormal activation patterns in both speech perception and production. There were bilateral differences in activation between PWS and controls in both the soundmorph paradigm and the DL production task. However, in the DL paradigm, the results were only significant with an uncorrected p-value. We also found lower fractional anisotropy (FA) (at an uncorrected level) in PWS in left inferior frontal gyrus (IFG), indicating dysfunctional connectivity, but no differences in grey matter. The results lend support towards functional abnormalities in speech lateralization, and to a differential involvement of the dorsal stream of speech processing in PWS. The results also lend support to the notion of a strong involvement of STS in speech perception in both PWS and controls. However, these this study is part of an ongoing project, and the findings may change as more data is collected