Cognitive performance and blood biomarkers: Insights into their relationship and predicting high Amyloid Probability...

BackgroundUnderstanding associations between cognitive performance and blood biomarkers supports diagnosis and treatment of Alzheimer's disease (AD); however, this relationship remains unclear.ObjectiveExploring associations between the Amyloid Probability Score (APS; PrecivityAD® blood test) and cognitive performance, and between Mini-Mental State Examination (MMSE) and Cogstate Brief Battery (CBB) in cognitively impaired older adults.MethodsOlder adults aged ≥ 60 years with MMSE from 10 to 27, recruited from a cohort in Japan, were assessed with the CBB, and plasma biomarkers to calculate APS. We used Spearman correlation to explore relationships; receiver operating curves and cross-validation to identify the best model for predicting high APS.ResultsAmong 46 participants (mean age = 78.3 ± 5.9; mean MMSE = 20.3 ± 4.6), 39.1% did not complete at least one test in the CBB. Lower MMSE were observed in those who were non-completers. MMSE correlated with Detection (Psychomotor function), Identification (Attention), and their composite (r = 0.34-0.52; p < 0.05; 95%CI excluding null value). Higher APS was seen in those who did not complete the One Card Learning (OCL-visual learning and short-term memory). The best model for predicting High APS included OCL completion status, MMSE and Years of Education, achieving accuracy = 0.808 and kappa = 0.606 in participants with MMSE < 21.ConclusionsOur findings suggest a consideration of incompletion when using CBB in cognitively impaired older adults and a potential approach to differentiate High APS group among those with moderate to severe dementia based on visual learning and short-term memory, global cognition and education level.