525 A population-based study of phenoconversion to parkinsonism from REM sleep behavior: a Population-based Study in the CLSA

Abstract

Abstract Introduction To date, studies have estimated the phenoconversion rate from sleep clinics, using polysomnography proven RBD. However, no population-based estimates have been reported, testing to what degree possible RBD, screened by questionnaire is associated with increased risk of neurodegeneration. Methods We included those aged 45–85 years, living in one of 10 Canadian provinces in between 2012–2015 (at the baseline), recruited via three population-based sampling methods. Dream enactment behavior/possible RBD was screened using the RBD1Q single question-questionnaire. De-novo parkinsonism was defined as free of pre-existing diagnosis at the baseline with a ‘new’ diagnosis at the follow-up (205–2019). Relative risk (log-binomial regression), hazard ratio (Cox regression), incidence rate (Poisson regression) between the affected group and the symptom naïve group were assessed, adjusting for age and sex (and total years of education and language). Results Overall, 58 participants phenoconverted into parkinsonism and 53 into dementia at the follow-up (mean intervals=3.06±0.37 years). Participants with dream enactment behavior had 2.75 times higher risk to phenoconvert into parkinsonism than the symptom-free. Similarly, those with dream enactment behavior at the baseline possessed higher risk to screening positive of parkinsonism. No difference in time to phenoconversion was found between groups, The results remained robust after excluding non-RBD related symptoms, such as apnea and non-REM sleep parasomnia. Conclusion Compared to symptom-free, those with pRBD had higher risk to developing parkinsonism in near future. Support (if any):