Imaging evidence for anatomical disturbances and neuroplastic compensation in persons with Tourette syndrome

BACKGROUND: Tourette syndrome (TS) is a disorder of chronic motor and vocal tics that begins in childhood. METHODS: A systematic Medline search was conducted to identify existing anatomical imaging studies in persons with TS. RESULTS: Thirty studies were identified, and their methods and findings were reviewed. Findings of reduced caudate volumes across the life span and thinning of sensorimotor cortices that is proportional with tic severity in children with TS implicate these regions in the genesis of tics. Hypertrophy of limbic and prefrontal cortices and a smaller corpus callosum accompany fewer symptoms in children with TS, likely representing an activity-dependent plasticity within these regions that help to modulate tic severity. CONCLUSION: Although existing studies differ with respect to sample size, gender composition, quality of clinical characterization, pulse sequences, and methods of image analysis, the preponderance of evidence suggests that disturbances in the development of the motor portions of cortical-subcortical circuits likely predispose to the development TS and that neuroplastic changes in control systems of the brain help to modulate the severity of symptom expression. These findings from cross-sectional studies require confirmation in more representative populations within longitudinal studies.