Is REM Sleep Behavior Disorder Changing? Secular Changes Versus Referral Patterns

BackgroundSince 2014, there has been increasing public outreach effort regarding isolated/idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD) in Montreal. ObjectiveTo assess if, over time, milder iRBD cases are presenting earlier. MethodsDisease-free survival was compared in two iRBD recruitment epochs: 2004 to 2013 ("earlier") versus 2014to 2022 ("later") and by referral type ("self-referral" vs. "conventional-referral") in three large centers. ResultsIn Montreal, among 209 subjects followed prospectively, shorter time to phenoconversion was observed in the earlier epoch (5-year phenoconversion = 42% earlier vs. 23% later); diagnosis before 2014 had a 1.8-fold phenoconversion hazard. However, no difference was observed in 248 subjects from Barcelona and 166 from Innsbruck. Analysis of Montreal data found that increased survival in the later epoch was driven by an increasing number of self-referrals, who phenoconverted at 1/3 the rate of physician-referred subjects. ConclusionsIncreased patient awareness of iRBD results in earlier presentation to clinical attention, with a longer time to phenoconversion.