Combining plasma biomarkers and cognitive challenge tests enhances prediction of functional trajectories of decline among older adults with cognitive impairment.

BackgroundPlasma biomarkers have emerged as promising, less invasive indicators of Alzheimer's disease (AD) pathology. However, biomarkers alone cannot indicate whether actual clinical symptoms are present or progressing. Plasma biomarkers when paired with specific cognitive deficits on brief novel Cognitive Challenge Tests (CCTs), provide excellent sensitivities to underlying AD pathology in preclinical and prodromal stage. There is a lack of data on the extent to which plasma biomarkers and CCTs independently and jointly, predict longitudinal functional decline in the earliest stages of cognitive impairment.ObjectiveTo evaluate whether plasma biomarkers and CCTs independently and in combination predict baseline and longitudinal changes on the Clinical Dementia Rating scale Sum of Boxes (CDR-SOB) among older adults with cognitive impairment without dementia.MethodsOlder adults aged 54 to 98 years diagnosed with cognitive impairment without dementia (n = 159) at baseline were followed annually for a minimum of 3 visits, mean follow-up was 41.5 months (SD 11.9). CDR-SOB trajectory was estimated using latent growth curve modeling. The associations between plasma biomarkers (p-tau217, GFAP, and NfL) and CCTs with baseline levels and longitudinal change in CDR-SOB were evaluated.ResultsAfter adjusting for age, sex, education, Hispanic ethnicity,