Clinical correlates of rapid eye movement sleep without atonia in Parkinson's disease.

OBJECTIVE: The aim of the present study was to investigate the relationship between rapid eye movement (REM) sleep without atonia (RWA) and Parkinson's disease (PD) progression.

METHODS: We quantified tonic and phasic RWA by performing polysomnography in 198 PD patients. We then correlated the extent of RWA with clinical patient characteristics.

RESULTS: PD patients were categorized into quartiles of tonic and phasic RWA. We found that patients with more RWA tended to be older and have longer PD duration, a greater likelihood of REM sleep behavior disorder (RBD), more advanced Hoehn & Yahr (H&Y) stage, a higher dose of parkinsonian medication, poorer cognitive performance, worse quality of life, and more severe sleep disturbance. After adjusting for age, sex, and PD duration, patients in the highest two RWA quartile were more likely to have severe PD (H&Y stage ⩾ 3.0) than those in the lowest RWA quartile.

CONCLUSIONS: These findings provide evidence that RWA, especially with regard to tonic muscle activity, is associated with PD severity.

SIGNIFICANCE: Further studies are warranted to determine the importance and utility of assessing RWA to evaluate sleep in PD patients.