Associations between Severity of Motor Function and Nonmotor Symptoms in Parkinson's Disease: A Post Hoc Analysis of the RECOVER Study

Abstract

Background: RECOVER (NCT00474058), a double-blind, placebo-controlled trial in patients with Parkinson's disease (PD) and unsatisfactory early-morning motor symptom control, demonstrated significant improvements with rotigotine in early-morning motor function (Unified Parkinson's Disease Rating Scale [UPDRS] III), and nocturnal sleep disturbances (modified Parkinson's Disease Sleep Scale [PDSS-2]), and improvements in nonmotor symptoms (NMS; Non-Motor Symptom Scale [NMSS]). Methods: Post hoc analyses investigated the correlation between motor symptom and NMS severity in PD by evaluating associations between UPDRS III and both NMSS and PDSS-2 scores. Categories were defined for UPDRS III, NMSS, and PDSS-2 total scores; analyses were conducted for the full analysis set (n = 267). Results: There was a trend toward increasing PDSS-2 and NMSS total and domain scores with increasing UPDRS III category at baseline and end of maintenance (EoM). Pearson correlation coefficients between UPDRS III and both NMSS and PDSS-2 total and domain scores were r = 0.12-0.44 (r² = 0.01-0.19) at baseline, r = 0.05-0.38 (r² = 0.00-0.14) at EoM, and r = -0.02-0.36 (r² = 0.00-0.13) for change from baseline to EoM. Conclusion: There was only a small correlation between severity of early-morning motor symptoms and overall burden of NMS and nocturnal sleep disturbances in RECOVER, suggesting that motor symptoms and NMS originate, at least partly, from distinct pathophysiological pathways.