Sleep enactment behaviors in Parkinson’s disease and multiple system atrophy: Beyond rem behavior disorder

Introduction Arousal-related “Sleep Enactment Behaviors” (SEBs) in Parkinson’s Disease (PD) and Multiple System Atrophy (MSA) consist of heterogeneous behaviors arising from NREM or REM sleep Their semeiological and electrophysiological aspects have not been elucidated so far. We describe the clinical features and EEG correlates of arousal-related NREM SEBs in PD and MSA. Materials and methods Twenty-four PD and 12 MSA patients underwent a video-polysomnography (VPSG) for dream enactment behavior. The recordings of 3 PD and 3 MSA patients (67.0 ± 6.9 years old, 4 men) in which a NREM/REM sleep pattern was recognizable were visually scanned to identify SEBs emerging from NREM sleep arousals. From all the NREM arousals, we distinguished “SEB arousals” and “No-SEB arousals” according to their semiological features at video, for each recording. For each patient, we extracted a 3-min EEG segment around each arousal. We computed EEG power in the time- frequency plan using a Morlet’s wavelet transform for SEB and No-SEB arousals. This wavelet transform was z-scored according to a baseline. This analysis was done for SEB and No-SEB arousals at F3, C3, O1, F4, C4, O2, Fz, Cz, Pz derivations referred to A1 + A2. A comparison of the normalized EEG power between SEB and No-SEB events was performed with a two-sample t -test, based on a fixed-effect analysis among patients. Results At video analysis, 25 NREM arousal-related SEBs were identified. Two independent scorers classified the NREM SEB arousals as (a) “simple” (15 episodes), (b) “pseudo-REM Behavior Disorder (RBD)” (3 episodes) and (c) “confusional”-type SEBs (7 episodes). The relative power spectrum analysis showed a power reduction at 5–6 Hz at frontal, central and occipital derivations bilaterally, starting around 100 s before SEB arousals ( p p Conclusion NREM arousal-associated SEBs in PD and MSA may show different semeiological pattern at video-PSG analysis. Moreover, their peculiar pattern of power spectrum EEG changes seems to suggest different underlying mechanisms compared to sleepwalking or confusional arousals. Acknowledgement We thank Mr. Jean Michel Duplantier for his logistic support.