Associated factors for REM sleep behavior disorder in Parkinson disease

OBJECTIVE: To investigate the frequency, phenomenology, and associated risk factors of REM sleep behavior disorder (RBD) in Parkinson disease (PD). METHODS: An unselected cohort of sleep-disturbed patients with PD (n=457) was investigated with video-supported polysomnography. We determined the frequency of RBD and analyzed the influence of age, clinical disease features, disease duration, cognitive and physical impairment, medication, comorbidity, and sleep architecture. RESULTS: The overall frequency of RBD was 46%. According to our cohort and modified definition, there was no preferred PD subtype for RBD (p=0.142). There was no gender preference (p=0.770). RBD was associated with older age (p=0.000). Adjusted for age and gender, patients with PD and RBD had longer disease duration (p=0.024), higher Hoehn & Yahr stages (p=0.002), more falls (p=0.018), more fluctuations (p=0.005), more psychiatric comorbidity (p=0.026), and a higher dose of levodopa (p=0.002). The presence of RBD was related to slightly increased sleep efficiency (p=0.007), a higher amount of REM sleep (p=0.000), and more periodic leg movements during sleep (p=0.019). CONCLUSION: RBD is a frequent and clinically relevant nocturnal disturbance for all stages of PD. It increases with age and disease duration and may contribute to the nocturnal problems of patients with PD and their bed partners.