Researchers have identified plasma phosphorylated tau biomarkers—pTau217 and pTau231—that can forecast dementia progression in Parkinson’s disease. The prospective longitudinal study reported that measuring these proteins may help predict the onset of cognitive decline in patients with Parkinson’s. The biomarker approach targets circulating forms of phosphorylated tau, a protein associated with neurodegenerative pathology across multiple diseases. In the study design, investigators tracked clinical outcomes over time while evaluating whether baseline or longitudinal biomarker signals were associated with later dementia development. If validated in broader cohorts, plasma pTau217/pTau231 could support earlier risk stratification and trial enrichment strategies in Parkinson’s, where diagnosing cognitive trajectory remains challenging. The work adds to the growing push toward blood-based biomarker tools to speed enrollment and improve monitoring.