Occurrence and clinical correlates of REM sleep behavior disorder in patients with Parkinson's disease over time

Abstract

Objective: To examine the occurrence and clinical and demographic correlates of REM sleep behavior disorder (RBD) in patients with Parkinson’s disease (PD) in a community based cohort over eight years.

Methods: 231 patients with PD were included in a population-based prevalence study in 1993. Patients were then followed prospectively and reexamined after four and eight years. Semi-structured interviews for information upon clinical and demographic data were applied at all study visits. Standardized rating scales of parkinsonism, depression, and cognitive impairment were used. The diagnosis of probable RBD (pRBD) was based on a sleep questionnaire. Proportional-odds ordinal logistic regression models for clustered data was used to study the relationship between pRBD and various demographic and clinical variables.

Results: 231 patients were evaluated for RBD in 1993 and after four and eight years 142 and 89 patients were available for re-evaluation. The frequency of pRBD varied from 14.6% to 27% during the study period. Probable RBD was related to male gender, higher dopaminergic treatment and less severe parkinsonism.

Conclusion: We found that the frequency of pRBD varied over time and that it is associated with male gender, less parkinsonism and higher levodopa equivalent dose. Our findings indicate that dopaminergic therapy may contribute to the expression of RBD and that RBD is symptomatic in earlier stages of PD.