Fluctuations in reaction time performance as a marker of incipient amyloid‐related cognitive decline in clinically unimpaired older adults.

Accumulating evidence suggests that fluctuations in reaction time (RT) performance across assessments, usually defined by intraindividual variability in RT (IIV‐RT), are associated with cognitive impairment and decreased neurobiological integrity. Computerized cognitive testing facilitates the study of IIV‐RT, allowing for precise and frequent RT measurements in remote settings. We investigated whether quantifying IIV‐RT over months on various remotely administered computerized RT tasks could aid in the detection of emerging cognitively decline in initially clinically unimpaired (CU) older adults with elevated Alzheimer’s disease (AD) biomarkers.