Related Experiment Video
Updated: May 12, 2026
A Simple Composite Phenotype Scoring System for Evaluating Mouse Models of Cerebellar Ataxia
Published on: May 21, 2010
A Severity-Agnostic Atrophy Pattern in Spinocerebellar Ataxia Type 3: Volumetrics from ENIGMA-Ataxia
Jason W Robertson1, Isaac Adanyeguh2, David J Arpin3
1Faculty of Computer Science, Dalhousie University, Halifax, Nova Scotia, Canada.
Background:
Spinocerebellar ataxia type 3 (SCA3) is a rare, inherited neurodegenerative disease characterized by progressive loss of motor coordination.
Objectives:
We undertook a multisite magnetic resonance imaging study to profile the spatial spread of atrophy across the brain, determine whether atrophy preferentially maps onto specific functional networks, and investigate the relationship between cerebellar and cerebral atrophy.
Methods:
Whole-brain grey and white matter (GM and WM) voxel-based morphometry was performed on 408 individuals with SCA3 (82 pre-ataxic) and 293 controls. The SCA3 cohort was stratified by ataxia severity to study progression. Cerebellar GM atrophy was mapped onto a task-based functional atlas. Cerebrocerebellar volumetric covariance was assessed to determine whether cerebral and cerebellar atrophy were coupled.
Results:
The atrophy pattern is spatially consistent but progressive in magnitude across the disease course. The greatest atrophy (Cohen's d > 1.5) occurred in the pons, cerebellar WM, and cerebellar peduncles; correlations with ataxia severity and duration were also strongest (-0.4 > r > -0.65) in those regions. Cerebellar GM atrophy was greatest (d ≅ 0.7) in functional regions associated with motor planning/execution, attention, and emotional processing. Sparse cerebral cortical atrophy appears only in the most severe disease subgroup, while striatal atrophy begins in the earliest stages but does not worsen with increasing clinical severity. Reduced cerebrocerebellar volumetric covariance is observed in SCA3 participants versus controls.
Conclusions:
Cerebellar and brainstem atrophy underlies greater ataxia severity in SCA3, but the spatial pattern of structural changes remains relatively consistent across the course of the disease. Cerebellar GM atrophy is spatially non-uniform, and occurs maximally in regions consistent with the motor and cognitive clinical presentation of SCA3. Cerebellar atrophy is not mirrored by corresponding cerebral structural changes. © 2026 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
