Plasma neurofilament light chain in early Parkinson's disease predicts motor complications: a prospective cohort...

Whether blood biomarkers can predict the development of motor complications in early-stage Parkinson's disease (PD) remains unclear. In this prospective longitudinal cohort study, 173 patients with early-stage PD were followed for up to seven years. Plasma neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP), phosphorylated tau181 (p-tau181), amyloid beta 42 (Aβ42), and amyloid beta 40 (Aβ40) were measured at baseline, 1-year, and 2-year follow-up using an ultrasensitive single-molecule array platform. Kaplan-Meier and Cox regression analyses were performed to identify predictors of motor fluctuations and dyskinesias. Motor fluctuations and dyskinesias occurred in 41.6% and 17.9% of participants, respectively. Patients who developed motor complications had higher baseline plasma NfL, GFAP, and Aβ40 levels. However, after adjustment for confounders, only higher baseline NfL independently predicted the future development of motor complications, whereas longitudinal changes in plasma biomarkers were not associated with these outcomes. Higher baseline levodopa daily dose and greater anxiety and depression scores were also identified as clinical predictors. These findings suggest that plasma NfL may serve as a minimally invasive biomarker for early risk stratification of motor complications in PD.