REM sleep behavior disorder in early Parkinson’s disease predicts the rapid dopaminergic denervation

To test the hypothesis that REM sleep behavior disorder (RBD) in early Parkinson's disease (PD) predicts rapid progression of dopaminergic denervation. 123I-FP-CIT single photon emission computed tomography (SPECT) scans were performed sequentially at baseline, 1 year, 2 years, and 4 years in 416 de novo patients with PD. RBD screening questionnaire scores >5 at baseline placed the participant in the likely-RBD group. Temporal changes in the specific binding ratio (SBR; caudate, putamen. sum of both, striatum) were compared between the likely-RBD and the non-likely-RBD groups for more or less affected striatum with a repeated measure ANOVA. Likely-RBD was reported in 37.7% of the drug-naïve PD patients at baseline. The likely-RBD and non-likely-RBD groups did not have significant differences in the baseline clinical features including gender, age, disease duration, UPDRS motor score, and striatal SBR. Striatal SBR decreased significantly over four years in both groups (P