Is Rapid Eye Movement Sleep Behavior Disorder a Risk Factor for Impulse Control Disorder in Parkinson Disease?

Objective: To assess the association between rapid eye movement sleep behavior disorder (RBD) and other determinants and incident impulse control disorder behaviors (ICBs) in patients with early Parkinson disease (PD) using longitudinal data from the Parkinson's Progression Markers Initiative.
Methods: Four hundred one newly diagnosed PD patients were prospectively evaluated at baseline (BL), month 6, and annually for 5 years. Probable RBD (pRBD) was assessed with the RBD Screening Questionnaire (RBDSQ) and dichotomized using a cutoff value of ≥6. The association of BL and time-dependent (TD) pRBD and other covariates with the development of ICB symptoms was evaluated using Cox proportional hazards regression and general estimating equation logistic regression. Models considered adjustment for age, sex, Movement Disorders Society Unified Parkinson's Disease Rating Scale part III, Geriatric Depression Scale (GDS-15), RBD medication use, total levodopa equivalent daily dose, and dopamine agonist (DA) and antidepressant medication use.
Results: Both BL pRBD and TD pRBD were not associated with an increased risk for incident ICB symptoms after adjustment for covariates (adjusted hazard ratio [HR] = 1.17, p = 0.458 and HR = 1.27, p = 0.257, respectively). In a modified TD pRBD model (ie, considering subjects as pRBD onward from the first time point with RBDSQ score ≥ 6), the risk for incident ICB symptoms was higher in pRBD in unadjusted (HR = 1.48, p = 0.038) but not adjusted (HR = 1.29, p = 0.203) models. TD DA use (HR = 1.64, p = 0.039), TD GDS-15 score (HR = 1.12, p < 0.001), and male sex (year 3: HR = 2.10, p = 0.009; year 4: HR = 3.04, p = 0.006; year 5: HR = 4.40, p = 0.007) were associated with increased ICB symptom risk.
Interpretation: pRBD is not clearly associated with ICB symptom development in early PD, in contrast to DA use, depression, and male sex. ANN NEUROL 2020;88:759-770.
(© 2020 American Neurological Association.)