In a recent study, researchers confirmed evidence that probable sleep behavior disorder (pRBD) features are a clinical marker for faster cognitive decline and possibly also motor progression in Parkinson disease (PD) patients, the latter for patients with a postural instability and gait dysfunction (PIGD) subtype early in disease. They screened for RBD in a cohort of 776 patients with PD whom they ascertained using a population-based strategy. Among participants with at least 1 follow-up (60%), they compared those with and without probable pRBD, estimating hazard rate ratios for progression events Unified Parkinson Disease Rating Scale (UPDRS-III) ≥35 and Mini-Mental State Exam (MMSE) ≤24. They found:
- Prevalence of pRBD at baseline was 21%.
- In adjusted Cox regression models among patients with a PIGD phenotype, those with pRBD progressed faster to a UPDRS-III≥ 35 (HR=1.92).
- Also, all patients with pRBD progressed twice as fast to a MMSE score≤ 24 (HR=2.04).
- In sensitivity analyses, using alternative definition of pRBD and accounting for bias due to loss to follow-up results remained similar.
Duarte Folle A, Paul KC, Bronstein JM, Keener AM, Ritz B. Clinical progression in Parkinson's disease with features of REM sleep behavior disorder: A population-based longitudinal study. [Published online ahead of print January 29, 2019]. Parkinsonism Relat Disord. doi:10.1016/j.parkreldis.2019.01.018.