Longitudinal Changes in Parkinson’s Disease Symptoms with and Without Rapid Eye Movement Sleep Behavior Disorder: The Oxford Discovery Cohort Study

Abstract

Background: Parkinson’s disease (PD) comorbid with rapid eye movement sleep behavior disorder (RBD) may show more severe motor and non motor symptoms, suggesting a distinct PD subtype. Objective: The aim of this study was to investigate the impact of RBD on the longitudinal change of motor and non motor symptoms in patients with PD. Methods: Patients with early PD (diagnosed within 3.5 years) recruited from 2010 to 2019 were followed every 18 months in the Oxford Parkinson’s Disease Centre Discovery cohort. At each visit, we used standard questionnaires and measurements to assess demographic features and motor and non motor symptoms (including RBD, day-time sleepiness, mood, autonomic symptoms, cognition,and olfaction). Data were analyzed with linear mixed effects and Cox regression models. Possible RBD (pRBD) was longitudinally determined according to RBD Screening Questionnaire scores.Results: A total of 923 patients were recruited (mean age:67.1 9.59 years; 35.9% female), and 788 had follow-upassessment(s) (mean: 4.8  1.98 years, range: 1.3–8.3).Among them, 33.3% were identied as pRBD (PD + pRBD).Patients with PD + pRBD had more severe baseline symp-toms and showed faster progression on Movement Disorder Society-Unied Parkinson’s Disease Rating Scale parts I and III, Purdue Pegboard test, a nd Beck Depression Inventory scores. Moreover, PD + pRBD was associated with an increased level of risk for mild cognitive impairment (hazardratio [HR] = 1.36, 95% condence interval [CI]: 1.01–1.83),freezing of gait (HR = 1.42, 95% CI: 1.10–1.86), and frequent falling (HR = 1.62, 95% CI: 1.02–2.60).Conclusions: Patients with PD + pRBD progress fasteron motor, mood, and cognitive symptoms, confirming a more aggressive PD subtype that can be identified at baseline and has major clinical implications. © 2021 International Parkinson and Movement Disorder Society