Parkinson’s disease-related brain metabolic patterns and neurodegeneration in isolated REM sleep behavior disorder

Objective: To elucidate the role of Parkinson’s disease (PD)-related brain metabolic patterns as a biomarker in isolated rapid-eye-movement sleep behavior disorder (iRBD) for future disease conversion. Method: This is a prospective cohort study consisting of 30 iRBD patients, 25 de novo PD patients with a premorbid history of RBD, 21 long-standing PD patients on stable treatment and 24 healthy controls. iRBD group was longitudinally followed up. All participants underwent 18F-Fluorodeoxyglucose (FDG) PET and were evaluated with olfaction, cognition, and the Movement disorders society-Unified PD Rating Scale (MDS-UPDRS) at baseline. From FDG-PET scans, we derived metabolic patterns from the long-standing PD group (PD-RP) and de novo PD group with RBD (dnPDRBD-RP). Subsequently, we calculated the PD-RP and dnPDRBD-RP scores in iRBD patients. We validated the metabolic patterns in each PD group and separate iRBD cohort (n=14). Result: The two patterns significantly correlated with ea...