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

Abstract

ObjectiveTo identify the consistent findings from the whole‐brain voxel‐based morphometry (VBM) studies on spinocerebellar ataxia type 2 (SCA2).MethodsThe whole‐brain VBM studies comparing SCA2 patients and healthy controls (HCs) 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 SCA2 patients and HCs were extracted separately from each cluster. A meta‐analysis was performed using anisotropic effect size‐based signed differential mapping (AES‐SDM) software.ResultsA total of five studies with 65 SCA2 patients and 124 HCs were included in the GM meta‐analysis. Four of the five studies with 50 SCA2 patients and 109 HCs 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.ConclusionsThe consistent findings from our meta‐analysis showed that GM volume reductions in SCA2 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 SCA2.

Neuroimaging Biomarkers in SCA2 Gene Carriers

“…Atrophy of the right temporo-occipital cortex (parahippocampal, fusiform and lingual gyri) was observed in a meta-analysis of the VBM studies [14] (Figure 2). Striata and thalami have normal volumes [12,14].…”

“…Differently from multiple system atrophy, the T2 signal in the striata is normal [9,11] (Figure 1). Morphometry performed on T1-weighted images using volumetry of regions of interest or whole-brain analytical software, including voxel-based morphometry (VBM) or tensor-based morphometry, allows a quantitative assessment of the selective brainstem and cerebellar atrophy in SCA2 [12][13][14] (Figure 2) which is already present in pre-symptomatic gene carriers [15,16] ( Figure 3). Atrophy of the right temporo-occipital cortex (parahippocampal, fusiform and lingual gyri) was observed in a meta-analysis of the VBM studies [14] (Figure 2).…”

“…Meta-analyses of different single studies, such as those recently published by Han et al [14] for voxel-based morphometry studies and by Krahe et al [43] for proton MR spectroscopy studies.…”

Cerebellar Abnormalities on Proton MR Spectroscopy and Imaging in Patients With Gluten Ataxia: A Pilot Study

“…The lobule X is also known as flocculonodular lobe and it plays an important role in regulating and orienting the eye movement through vestibulo-ocular reflex (Stoodley and Schmahmann, 2009 ; Stoodley et al, 2012 ). It also affects the body equilibrium during stance and gait along with lobule IX (Han et al, 2018 ). Thus, any change in the volume of lobule X may directly affect movement of eyes which is usually seen in ataxias (nystagmus).…”

Molecular Mechanisms and Therapeutics for Spinocerebellar Ataxia Type 2

“…Recent fractal analysis on the index of the structural complexity of the cortical gray matter and white matter demonstrated the reduction of the structural complexity of the cerebellum and cerebral cortex in SCA2 patients in vivo [71]. The recent whole-brain voxel-based morphometry (VBM) in vivo studies on SCA2 showed that the gray matter volume reductions in SCA2 patients were mainly observed in the cerebellum and the part of the cerebral cortex in the supratentorial regions responsible for the regulation of cognitive functions and emotions, whereas significant white matter volume reductions widely existed in the cerebellum along with its afferent pathways and pyramidal system [72]. Another recent VBM study has shown the significant gray matter loss in the bilateral regions of the anterior cerebellar hemisphere (I-V), the posterior lobe (VI-IX), and the posterior vermis (VI-IX).…”