Exploratory serum biomarker profiling in idiopathic REM sleep behavior disorder: evidence of early neurodegenerative signatures: a pilot study

BACKGROUND: Idiopathic REM sleep behavior disorder (iRBD) indicates an early α-synucleinopathy, offering a window for early detection and intervention. OBJECTIVE: Explore a serum-based biomarker panel, comprising NfL, GFAP, t-tau, and UCH-L1, in patients with iRBD, and compare to individuals with synucleinopathy and healthy controls. METHOD: This is a cross-sectional, observational study. Serum biomarkers were measured using the single molecule array technique. Clinical evaluation included standardized assessments of sleep, cognitive function, motor symptoms, and psychiatric features. RESULTS: GFAP levels were significantly higher in the iRBD group than in the control and synucleinopathy groups. Serum NfL levels yielded conflicting results. T-tau and UCHL-1 protein levels were lower in the iRBD and synucleinopathy groups compared to the control group. CONCLUSION: Our findings suggest that serum levels of NfL, GFAP, t-tau, and UCH-L1 may serve as potential biomarkers in iRBD, primarily GFAP levels.