Polysomnographic data in Dementia with Lewy Bodies: correlation with clinical symptoms and comparison with other α-synucleinopathies

Introduction: Sleep dysfunction is frequent in Dementia with Lewy Bodies (DLB), but polysomnographic (PSG) data is scarce. Our objectives were to: (1) compare PSG data between DLB patients and age normative values (NV), Parkinson's Disease (PD) and idiopathic REM sleep behavior disorder (iRBD) patients; (2) evaluate the relation between of OSA, Fluctuations and Hypersomnolence and PSG data. Methods: We selected all consecutive patients with DLB, PD and iRBD that underwent video-PSG during a two year period. Clinical data was collected by file review. Video-PSG data included sleep structure, Apnea-Hypopnea Index (AHI), REM sleep atonia indexes and video file inspection of motor events (ME) during REM sleep. Results: Subjects: In this study, 19 DLB, 51 PD and 20 iRBD patients participated. Of those, nine DLB (DLB-RBD) and 23 PD (PD-RBD) patients had RBD. Compared to NV, DLB patients had significantly lower sleep efficiency, total sleep time, and REM sleep duration and higher sleep latency, wake after sleep onset and N2 duration. There were no significant relations between PSG data and OSA, hypersomnolence or fluctuations. Sleep latency and AHI were significantly higher and lower, respectively, in DLB compared to PD patients. ME frequency was higher in iRBD. Conclusion: DLB patients present significant sleep fragmentation and shortened total and REM sleep time. These changes were not related with OSA, fluctuations or hypersomnolence, suggesting a different pathophysiology. PSG data was similar in the three RBD groups, in accordance with a common neuropathological origin, except for an increase in RBD severity in patients with iRBD.