Brain volumetric changes in pediatric patients with Tourette syndrome

Tourette syndrome (TS), a common pediatric neurodevelopmental disorder characterized by motor and vocal tics, is often accompanied by high rates of comorbidities, including attention-deficit/hyperactivity disorder and obsessive-compulsive disorder. The TS pathophysiology remains incompletely understood, with current theories focusing on the basal ganglia and cortico-striatal-thalamo-cortical (CSTC) circuit dysfunction. However, discrepancies in the brain volumetric changes were reported by studies involving children with TS. Therefore, the present study aimed to analyze the brain volumetric changes in the treatment-naïve pediatric TS patients without comorbidities to reduce the possible effect of medications and comorbidities. Forty pediatric TS patients and 40 age- and sex-matched healthy controls underwent brain magnetic resonance imaging, and their brain volumes were measured using FreeSurfer software. Our results revealed the trend of volumetric reductions in the right short insular gyrus and right inferior circular insular sulcus among TS patients, suggesting possible insular involvement in TS pathophysiology. Additionally, the loss of normal asymmetry was observed in the subcortical gray matter regions, including the putamen and accumbens nucleus, in TS patients. By focusing on a carefully selected, comorbidity-free and treatment-naïve cohort, the present study provides a clearer picture of the structural brain alterations directly related to TS. Our study results offer new insights into the morphometric alterations associated with TS, highlighting the potential role of the insula and basal ganglia in its pathogenesis. Further studies exploring the relationship between the volumetric changes and clinical course are warranted.