Objective:

To report the electrophysiological findings presented in somatosensory evoked potentials in a cohort of patients with spinocerebellar ataxias type 3 and 10, comparing them.

Background:

Although spinocerebellar ataxias (SCA) are heterogeneous diseases , the Brazilian patients with SCA 10 tend to have a low incidence of peripheral neuropathy. Electrophysiological testing might uncover subclinical abnormalities, and somatosensory evoked potentials (SSEPs) can provide further insights by evaluating the dorsal column-medial lemniscus pathway.

Design/Methods:

This is a cross-sectional study evaluating the somatosensory evoked potentials in a cohort of patients with SCA 3 (n = 15) and SCA 10 (n = 8). The patients underwent a clinical evaluation in which demographic and clinical data, such as sex, age, duration of disease, and SARA scores, were registered. After the clinical evaluation, all patients were submitted to somatosensory evoked potentials following the American College of Neurophysiology guidelines. We evaluated amplitudes, latencies, and interpeak latencies for the N9, N20, N21, and P40 potentials.

Results:

The groups did not differ regarding demographic and clinical data. In the cohort of patients with SCA 3, 86% of the sample (n = 13) presented SSEP abnormalities, while only 12.5% (n = 1) of the SCA 10 sample presented abnormalities, and this difference was statistically significant (p = 0.001). Correlations of SSEP abnormalities to SARA scores (SCA 3: Rho = 0.11, p = 0.6866; SCA 10: Rho = - 0.41, p = 0.31) and duration of disease (SCA 3: Rho = - 0.13, p = 0.626; SCA 10: Rho = - 0.58, p = 0.136) did not present statistical significance.

Conclusions:

Our preliminary data indicate that the Brazilian patients with SCA 10 present a low incidence of SSEP abnormalities, suggesting that the dorsal column-medial lemniscus pathway. Our findings are following most of the descriptions of clinical phenotypes for Brazilian patients with SCA 10.