Regional brain and ventricular volumes in Tourette syndrome

Background: The pathophysiology of Tourette syndrome (TS) is thought to inv olve disturbances in corticostriato-thalamo-cortical circuitry. The morphol ogical characteristics of the cortical and associated white matter portions of these circuits have not been previously examined in TS subjects. Methods: High-resolution anatomical magnetic resonance images were acquired in 155 TS and 131 healthy children and adults. The cerebrums and ventricle s were isolated and then parcellated into subregions using standard anatomi cal landmarks. Results: For analyses that included both children and adults, TS subjects w ere found to have larger volumes in dorsal prefrontal regions, larger volum es in parietooccipital regions, and smaller inferior occipital volumes. Sig nificant inverse associations of cerebral volumes with age were seen in TS subjects that were not seen in healthy controls. Sex differences in the par ieto-occipital regions of healthy subjects were diminished in the TS group. The age-related findings were most prominent in TS children, whereas the d iminished sex differences were most prominent in TS adults. Group differenc es in regional ventricular volumes were less prominent than in the cerebrum . Regional cerebral volumes were significantly associated with the severity of tic symptoms in orbitofrontal, midtemporal, and parieto-occipital regio ns. Conclusions: Broadly distributed cortical systems are involved in the patho physiology of TS. Developmental processes, sexual dimorphisms, and compensa tory responses in these cortical regions may help to modulate the course an d severity of tic symptoms.