Objective: The aim of the study was to know the association of degree of atrophy in brain areas with clinical severity in SCA patients.

Background: Spinocerebellar ataxia (SCA) is a progressive neurodegenerative disorder with prominent clinical heterogeneity amongst the subtypes. Clinical manifestations include gait imbalance, opthalmoplegia, dysarthria, pyramidal and extrapyramidal signs. This clinical diversity is the result of unstable trinucleotide (CAG) repeat expansion especially in SCA type 1, 2 and 3 patients. This could be indicative of a differential neuronal loss in the SCA subtypes thus culminating into a differential clinical profile.

Methods: Clinical severity was assessed by International Cooperative Ataxia Rating Scale (ICARS) in the genetically proven SCA (n = 49, age = 34 ± 9.4 yrs) patients. Then MRI was performed by using a 3T scanner (Philips, Achieva) to obtain 3D T1-weighted scans of the whole brain and analysed by FreeSurfer (version 5.3) software in the same SCA patients. MRI parameters used in T1-weighted scans were: Voxel size = 0.6×0.6×1, FOV = 240×240×180 and flip angle = 8ᵒ. Based on the distribution of data, Pearson’s correlation (for parametric data) and Spearman’s rank correlation (for nonparametric data) analyses were done between brain areas and ICARS score of SCA patients.

Results: In SCA patients, ICARS showed a significant inverse correlation with cortical thickness of left rostral middle frontal (r = -0.382, p = 0.007), left caudal middle frontal (r = -0.324, p = 0.023), left medial orbitofrontal (r = -0.351, p = 0.013), left middle temporal (r = -0.324, p = 0.023), right middle temporal (r = -0.292, p = 0.042) and right entorhinal (r = -0.286, p = 0.046). Furthermore, the subcortical volume of midbrain (r = -0.472, p = 0.001), pons (r = -0.523, p = <0.001), medulla (r = -0.462, p = 0.001) and the total brainstem (r = -0.534, p = <0.001) were significantly associated with clinical severity in SCA patients.

Conclusions: We have found a significant correlation between the degree of atrophy in certain cortical and subcortical areas (known to be involved in regulation of motor movements) and the clinical severity score in SCA patients.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/cortical-and-brainstem-neurodegeneration-associate-with-the-clinical-severity-in-spinocerebellar-ataxia-patients/