Introduction: Subclinical neuropathy is an important feature of spinocerebellar ataxias (SCA) but the true prevalence and electrophysiological characteristics in genetically proven patients of SCA 1, 2 and 3 are largely unknown.
Methods: We prospectively compared the electrophysiological characteristics of neuropathy in 61 genetically confirmed cases of SCA (SCA1=28, SCA2=16 and SCA3=17). Nerve conduction studies were performed in at least one sensory and one motor nerve, in right upper and lower limb using standard methods.
Results: The mean age of patients and duration of illness were comparable among SCA groups (mean age (years): SCA1-34.1±12.7, SCA2-35.2±13.9 and SCA3-38.1±11.3; mean duration (years): SCA1-5.4, SCA2-6.1, and SCA3-4.4). Electrophysiological evidence of neuropathy was highest in SCA1 (96.4%), followed by SCA3 (94.1% and SCA2 (87.5%). A mixed sensorimotor neuropathy was commonly observed in all the subgroups (SCA1-78.6%, SCA2-50%, and SCA3-41.2%). Pure sensory neuropathy was most common in SCA3 (55.9%), followed by 31.3% in SCA2 and 17.9% in SCA1. Pure motor neuropathy was uncommon (6.3% in SCA2 and none in SCA1 and SCA3).
Conclusions: Electrophysiological evidence of mixed sensorimotor and pure sensory neuropathy is seen in all the three subtypes of SCAs, while pure motor neuropathy is distinctly uncommon.
Copyright © 2011 Elsevier B.V. All rights reserved.