Researchers identified plasma pTau217 and pTau231 as biomarkers that can forecast dementia progression in Parkinson’s disease. In a prospective longitudinal study, the plasma phosphorylated tau markers were used to predict the onset of dementia among Parkinson’s patients. This adds to the growing push for blood-based, stage-relevant biomarkers in neurodegeneration, especially where early cognitive decline is hard to measure reliably. It also broadens the clinical utility of tau assays beyond Alzheimer’s into Parkinson’s dementia risk stratification. The key outcome is the prognostic framing—using blood markers to estimate future dementia development—positioning pTau217/pTau231 as candidates for trials and clinical monitoring.