Subcortical volumes in girls with Tourette syndrome - Support for a gendereffect

Objective: To test whether girls with Tourette syndrome (TS) show subcortic al morphology that differentiates them from control subjects. Methods: MRI- based subcortical assessment was completed on 19 girls with TS age 7 to 15 years, 11 with TS only, and 8 with TS plus attention deficit hyperactivity disorder (TS + ADHD), and on 21 age- and sex-matched controls. The structur es measured were the caudate, putamen, globus pallidus, and lateral ventric le volumes. Whole-brain-corrected volumes and asymmetry indices were compar ed using two- and three-group designs (i.e., TS versus control; TS-only ver sus TS + ADHD versus control). Results: Two-group comparisons demonstrated no robust significant differences between girls with TS and gender-matched controls. Three-group comparisons demonstrated that TS-only subjects had si gnificantly small lateral ventricles compared with TS + ADHD and control su bjects. Because the two-group comparisons of the current study differed fro m previous reports of putamen asymmetry index as a marker for TS, retrospec tive comparisons with data from boys were performed. These additional compa risons showed that girls with TS had putamen asymmetry indices similar to t hose of boys with TS; however, control girls also showed those same pattern s. Conclusions: Basal ganglia volume and asymmetry differences do not disti nguish the girls with TS from matched controls. Gender differences confound the association between putamen asymmetry and TS. Although the numbers are small and the clinical significance is unclear, this study further indicat es that girls with TS-only have smaller lateral ventricular volumes than co ntrol subjects and those with TS + ADHD.