REM and NREM sleep enactment behaviors in Parkinson's disease, Parkinson's disease dementia, and dementia with Lewy bodies

Background/objective: Nocturnal sleep enactment behaviors (SEBs) are common in patients affected by Parkinson's disease (PD), dementia associated with Parkinson's disease (PDD), and dementia with Lewy bodies (DLB). We investigated the occurrence and neurobiological significance of abnormal SEBs in the context of PD without cognitive decline compared to PDD/DLB patients. Methods: We evaluated a sample of 139 patients with PD, PDD, or DLB in a cross-sectional survey. One hundred and seventeen patients showing either no cognitive impairment (PD group) or meeting the diagnostic requirements for dementia (PDD/DLB group) underwent video-polysomnography. Seventy subjects (42 males) in whom a clear-cut diagnosis of abnormal sleep-related motor-behavioral episodes was possible were included in the final analysis. Results: SEBs consisting of RBD or occurring on arousal from NREM or REM sleep were globally more frequent in the dementia group (PDD/DLB) than in the PD group (p= 0.001), the difference being statistically significant for arousal-related episodes (p= 0.002), while a trend emerged for RBD (p= 0.07). Male sex, daytime sleepiness, higher motor impairment, and lower mini-mental score were significantly more frequent with the occurrence of abnormal sleep-related motor-behavioral episodes. Conclusion: SEBs in PD, PDD, and DLB may consist of RBD episodes or of arousal-related NREM and REM episodes. These latter are more frequent in patients with PDD/DLB and seem to be mainly related to more advanced stages of disease with a higher degree of cognitive decline.