Inter-rater reliability for identification of REM sleep in Parkinson's disease.

Recently described functional connections between basal ganglia and brainstem circuits provide a neurobiologic basis for the absence of REM sleep atonia in Parkinson's disease (PD). However, identifying atypical REM sleep in PD may be problematic. Reliable sleep staging has never been demonstrated in such patients. In this study, 3 experienced scorers independently evaluated overnight polysomnograms from 10 (PD) patients. Results indicated good agreement for distinguishing REM from NREM sleep and waking. Reliable differentiation among NREM stages was more difficult to achieve. The results suggest that, despite suspension of REM sleep atonia accompanying PD, trained scorers can distinguish REM from wakefulness and NREM sleep.