Longitudinal assessment of probable rapid eye movement sleep behaviour disorder in Parkinson's disease.

Background and purpose Rapid eye movement (REM) sleep behaviour disorder (RBD) is frequently present in patients with Parkinson's disease (PD) and may have prognostic implications. There are few longitudinal studies of RBD in patients with PD. Our aim was to investigate whether RBD was a persistent feature in a follow-up study of 107 patients with PD. Methods After a mean follow-up time of 3 years, 96 patients were available for reassessment. Probable RBD (pRBD) was diagnosed by the REM sleep behaviour disorder screening questionnaire. Results At follow-up, pRBD was found in 49% of the patients, versus 38% at baseline. The pRBD status remained unchanged in three-quarters of the patients, whilst 17% had new pRBD symptoms. Disease duration was longer in the pRBD group, 9.4 vs. 7.6 years (P = 0.02). Conclusions Probable RBD is a persistent feature in PD and probably increases over time.