REM sleep behavior disorder: Association with motor complications and impulse control disorders in Parkinson's disease

Objective: Clinical phenotypes such as old age, longer disease duration, motor disability, akineto-rigid type, dementia and hallucinations are known to be associated with REM sleep behavior disorder (RBD) in Parkinson's disease (PD). However, the relationship between motor fluctuations/impulse control and related behaviors (ICRB) and RBD is not clear. We designed this study to elucidate the clinical manifestations associated with RBD to determine the implications of RBD in PD. Design: In a cross-sectional study, a total of 994 patients with PD were interviewed to determine the presence of RBD and their associated clinical features including motor complications and ICRB. Results: Of the 944 patients, 578 (61.2%) had clinical RBD. When comparing the clinical features between patients with RBD (RBD group) and without RBD (non-RBD group), older age, longer disease duration, higher Hoehn and Yahr stage (H&Y stage), higher levodopa equivalent daily dose (LEDD), and the existence of wearing off, dyskinesia, freezing, and ICRB, especially punding, were associated with the RBD group compared to the non-RBD group (. P<.05 in all). Multivariate analysis showed that motor complications including wearing off, peak dose dyskinesia, and diphasic dyskinesia were the only relevant factors for RBD after adjusting for age and disease duration. Conclusion: Motor complications and ICRB are more frequent in patients with RBD than in patients without RBD. In addition, motor complications are related to RBD even after adjusting for age and disease duration.