Voxel‐based meta‐analysis of gray and white matter volume abnormalities in spinocerebellar ataxia type 2

Objective To identify the consistent findings from the whole‐brain voxel‐based morphometry ( VBM ) studies on spinocerebellar ataxia type 2 ( SCA 2). Methods The whole‐brain VBM studies comparing SCA 2 patients and healthy controls ( HC s) were systematically searched in PubMed, Embase databases from January 2000 to June 2017. The coordinates with significant differences in gray matter ( GM ) and white matter ( WM ) between SCA 2 patients and HC s were extracted separately from each cluster. A meta‐analysis was performed using anisotropic effect size‐based signed differential mapping ( AES ‐ SDM ) software. Results A total of five studies with 65 SCA 2 patients and 124 HC s were included in the GM meta‐analysis. Four of the five studies with 50 SCA 2 patients and 109 HC s were included in the WM meta‐analysis. Significant and consistent GM volume reductions were detected in bilateral cerebellar hemispheres, cerebellar vermis, the right fusiform gyrus, the right parahippocampal gyrus, and the right lingual gyrus. The WM volume reductions were observed in bilateral cerebellar hemispheres, cerebellar vermis, middle cerebellar peduncles, pons, and bilateral cortico‐spinal projections. The findings of the study remained largely unchanged in jackknife sensitivity analysis. Conclusions The consistent findings from our meta‐analysis showed that GM volume reductions in SCA 2 patients were not limited in cerebellum while significant WM volume reductions widely existed in cerebellum and pyramidal system. The findings provide morphological basis for further studies on SCA 2.