Evidence of different grey matter volume patterns in men and women who stutter - An explorative structural MRI study.

Developmental stuttering is a disorder with a high degree of heterogeneity, both behaviourally and neurologically. Research from different perspectives of stuttering indicates that sex is a potentially differentiating factor. In our study we explored if sex is related to variability of grey matter volume (GMV) patterns in adults with developmental stuttering. We used MRI to collect data on GMV from 24 righthanded adults who stutter (9 women and 15 men) and 29 righthanded fluent controls (10 women and 19 men). We analysed the following for 24 ROIs of the language system: 1) whole-group differences between the stuttering group and controls and 2) interaction between group (adults with stuttering versus controls) and sex. Our explorative results indicate that differences in grey matter volume between adults with stuttering and fluent adults are sex-specific for several areas involved in speech and language processing. We found an interaction between group and sex for the right BA45. The interaction indicates that men who stutter have larger GMV in this area compared to fluent men while women who stutter have smaller GMV compared to fluent women. Further, we found indications of sex-specific patterns in other areas of the bilateral inferior frontal cortex, but not the BA44, as well as in the cerebellum and the striatum.