Parkinson's disease motor progression in relation to the timing of REM sleep behavior disorder presentation: an exploratory retrospective study.

REM sleep behavior disorder (RBD) is a frequent non-motor symptom of Parkinson's disease (PD), and the timing of its presentation might have a role in the underlying neurodegenerative process. Here, we aimed to define the potential impact of probable RBD (pRBD) on PD motor progression.We conducted a longitudinal retrospective study on 66 PD patients followed up at the University Hospital of Rome Tor Vergata. Patients were divided into three groups: with post-motor pRBD (pRBD, n = 25), without pRBD (pRBD, n = 20), and with pre-motor pRBD (pRBD, n = 21). Hoehn and Yahr (H&Y) scores, Unified PD Rating Scale (UPDRS) motor scores, and levodopa equivalent daily dose were collected at two follow-up visits conducted in a 5-year interval (T0 and T1). pRBD patients had a greater rate of motor progression in terms of the H&Y scale compared to pRBD and pRBD patients, without the influence of anti-parkinsonian treatment.These preliminary findings suggest that the post-motor occurrence of pRBD can be associated with an acceleration in PD motor progression.