Structural and functional alterations in the brain gray matter among Tourette syndrome patients: a multimodal meta-analysis of fMRI and VBM studies.

Background: Tourette syndrome (TS) is a prevalent neurodevelopmental disorder with an uncertain etiology. Numerous neuroimaging studies have investigated patients with TS, but their conclusions remain inconsistent. The current study attempted to provide an unbiased statistical meta-analysis of published neuroimaging studies of TS.

Methods: A comprehensive literature search was conducted to identify voxel-based whole-brain morphology (VBM) and functional magnetic resonance imaging (fMRI) studies related to TS. Two separate meta-analyses of neurofunctional activation and gray matter volume (GMV) were performed using a seed-point-based d-mapping software package, followed by joint and subgroup analyses.

Results: 11 VBM studies and 18 fMRI studies were included in this study. We found that grey matter volumes were significantly decreased in the right anterior cingulate/paracingulate gyri and the left postcentral gyrus; while the cerebellum, bilateral cortico-spinal projections, and striatum showed increased GMV in patients with TS. In fMRI studies, patients with TS showed overactivation in the right superior frontal gyrus and right superior temporal gyrus, and significant hypoactivation in left SMA. In the multimodal studies, TS patients showed that there was an overlap between decreased GMV and hypoactivation in the right median cingulate/paracingulate gyri.

Conclusion: Abnormal alterations in the structure and function of the brain regions may play a role in the pathogenesis of TS in patients, and may be used as an imaging indicator for patients with TS to be diagnosed.