Abnormal Findings in Polysomnographic Recordings of Patients with Spinocerebellar Ataxia Type 2 (SCA2).

Spinocerebellar ataxia type 2 (SCA2) is characterized by a progressive cerebellar syndrome, and additionally saccadic slowing, cognitive dysfunction, and sleep disorders. The aim of this study was to assess the frequency of abnormal findings in sleep recordings of patients with SCA2. Seventeen patients with genetically confirmed SCA2 from the Movement Disorders Outpatient group of the Hospital de Clínicas da UFPR were evaluated with a structured medical interview and the Scale for the Assessment and Rating of Ataxia (SARA). Polysomnographic recordings were performed and sleep stages were scored according to standard criteria. There were 10 male subjects and 7 females, aged 24-66 years (mean 47.44). A sex- and age-matched control group of healthy subjects was used for comparison. There was a reduction of rapid eye movement (REM) sleep in 12 (70.58%), increased REM latency in 9 (52.94%), increased obstructive sleep apnea-index in 14 (82.35%), absent REM density (REM density was calculated as the total number of 3-s miniepochs of REM sleep with at least 1 REM per minute) in 13 (76.47%), and markedly reduced REM density in 4 (23.52%). There was an indirect correlation according to the SARA scale and the REM density decrease (r = - 0.6; P = < 0.001); and with a disease progression correlating with a reduction in the REM density (r = - 0.52, P = 0.03). In SCA2, changes occur mainly REM sleep. The absence/decrease of REM sleep density, even in oligosymptomatic patients, and the correlation of this finding with disease time and with the SARA scale were the main findings of the study.