A 5-Year Longitudinal Clinical and Magnetic Resonance Imaging Study in Spinocerebellar Ataxia Type 3.

Background: The natural history of neurodegeneration in spinocerebellar ataxia type 3/Machado Joseph disease is still unclear. Here, we built a long-term longitudinal clinical and neuroimaging study to address this point.

Methods: Twenty-three patients with spinocerebellar ataxia type 3/Machado Joseph disease and 22 healthy controls underwent 3T MRI twice 5.0 years apart. T1 and diffusion tensor imaging sequences were obtained. We used T1 multiatlas, diffusion tensor imaging multiatlas, SpineSeg, and CERES-SUIT for cerebral gray and white matter, spinal cord and cerebellar analyses, respectively. Clinical severity was assessed with scale for assessment and rating of ataxia. Analysis of covariance evaluated longitudinal between-group changes. Effect sizes were calculated for each significant result.

Results: Progressive volumetric abnormalities were most evident in the cerebellum (Lobule X and Crus II; effect size, 2.0), followed by the basal ganglia (effect size, 0.7). The cerebellar peduncles had the largest white-matter diffusivity changes (effect size, 1.29). Scale for assessment and rating of ataxia-related effect size was 0.82. We failed to identify progressive spinal cord abnormalities.

Conclusions: Longitudinal changes in spinocerebellar ataxia type 3/Machado Joseph disease are more evident in the cerebellum and connections, followed by the basal ganglia. © 2020 International Parkinson and Movement Disorder Society.