Relationship of plasma biomarkers to digital cognitive tests in Alzheimer's disease

Abstract INTRODUCTION A major limitation in Alzheimer's disease (AD) research is the lack of the ability to measure cognitive performance at scale—robustly, remotely, and frequently. Currently, there are no established online digital platforms validated against plasma biomarkers of AD. METHODS We used a novel web‐based platform that assessed different cognitive functions in AD patients (N = 46) and elderly controls (N = 53) who were also evaluated for plasma biomarkers (amyloid beta 42/40 ratio, phosphorylated tau ([p‐tau]181, glial fibrillary acidic protein, neurofilament light chain). Their cognitive performance was compared to a second, larger group of elderly controls (N = 352). RESULTS Patients with AD were significantly impaired across all digital cognitive tests, with performance correlating with plasma biomarker levels, particularly p‐tau181. The combination of p‐tau181 and the single best‐performing digital test achieved high accuracy in group classification. DISCUSSION These findings show how online testing can now be deployed in patients with AD to measure cognitive function effectively and related to blood biomarkers of the disease. Highlights This is the first study comparing online digital testing to plasma biomarkers. Alzheimer's disease patients and two independent cohorts of elderly controls were assessed. Cognitive performance correlated with plasma biomarkers, particularly phosphorylated tau (p‐tau)181. Glial fibrillary acidic protein and neurofilament light chain, and less so the amyloid beta 42/40 ratio, were also associated with performance. The best cognitive metric performed at par to p‐tau181 in group classification.