Researchers unveiled an endpoint dilution seed amplification assay (SAA) that quantifies α‑synuclein seeding activity in cerebrospinal fluid with higher precision. The team reported improved sensitivity and reproducibility versus prior methods, enabling quantification of seed titres rather than binary detection. Authors propose the assay as a tool for staging, prognosis and pharmacodynamic assessment in Parkinson’s disease trials. The paper provides analytical validation data and pilot clinical correlations with disease status. Sponsors and trial groups developing anti‑α‑synuclein therapeutics could adopt this assay to measure target engagement and patient selection in upcoming studies.