Incidence and Progression of Rapid Eye Movement Behavior Disorder in Early Parkinson's Disease

Abstract

Background: Rapid eye movement (REM) sleep behavior disorder (RBD) is associated with neurodegenerative diseases; however, few longitudinal studies assess the individual evolution of RBD and REM sleep without atonia (RWA) in Parkinson's disease (PD). Objectives: We aimed to evaluate RBD and RWA changes over time as well as potentially influential factors. Methods: RBD and RWA were analyzed using video-supported polysomnography (vPSG) in initially de novo PD patients at baseline and every 2 years for a total of 6 years. The influence of time, age, sex, levodopa equivalent daily dose (LEDD), unified Parkinson's disease rating scale (UPDRS) sum scores, benzodiazepine intake, Mini-Mental State Examination (MMSE) total scores, and dyskinesia on RWA were investigated using mixed-effect models to account for intra-individual correlations. Results: After 6 years, vPSG data were available from 98 of the initial 159 de novo PD patients. RBD prevalence increased from 25% at baseline to 52%. Of the 31 PD patients with RBD and valid vPSGs at all time-points, RWA increased from an average of 19% at baseline to 41% at 6-year follow-up modeled to grow by 29.7% every 2 years (P < 0.001). Time was an independent factor (P < 0.001) for RWA increase. Age was an independent factor influencing RWA increase (P = 0.04). Sex, LEDD, UPDRS sum scores, benzodiazepines, MMSE total scores, and dyskinesia did not have any significant influence. Conclusions: RBD and RWA increased significantly over time in PD; time and age were independent factors in a prospective cohort. RBD and RWA can be considered PD progression markers.