Assessment of Glymphatic System Function in Children with Tourette Syndrome Using DTI-ALPS.

Objectives: This study aimed to evaluate glymphatic system function in children with Tourette syndrome (TS) using diffusion tensor image analysis along the perivascular space (DTI-ALPS), and explored its potential role in TS pathophysiology.

Methods: Seventy-six children with TS and eighty-two age- and sex-matched typically developing (TD) controls underwent DTI scans. Glymphatic function was quantified using the ALPS index, derived from atlas-based regions of interest in the superior corona radiata and superior longitudinal fasciculus. We examined associations between the left ALPS index (ALPS_L) and clinical measures, including tic severity (Yale Global Tic Severity Scale, YGTSS) and quality of life (Gilles de la Tourette Syndrome Quality of Life Scale, GTS-QOL). Mediation analysis assessed whether tic severity mediated the relationship between ALPS_L and GTS-QOL subscales.

Results: The ALPS_L was significantly reduced in the TS group compared to the TD group (P < 0.05). The ALPS_L showed significant negative correlations with YGTSS motor tic (r = -0.850, P < 0.001), total tic (r = -0.702, P < 0.001), and global tic severity (r = -0.629, P < 0.001). It was also negatively correlated with the physical/ADL (r = -0.265, P = 0.020) and obsessive-compulsive (r = -0.380, P < 0.001) subscales of GTS-QOL. Motor tic severity partially mediated the relationship between the ALPS_L and physical/ADL scores (β = -0.037, 95% CI: [-0.060, -0.015]).

Conclusions: Children with TS exhibit altered glymphatic function, associated with tic severity and impaired quality of life. These findings suggest glymphatic dysfunction may underlie TS-related neurobiological abnormalities.