The association between daily real-time assessment of subjective cognitive function and objective cognition using ecological momentary assessment.

Objective: Subjective cognitive decline is a known risk factor for dementia, but associations between subjective and objective cognition have been inconsistently reported.This may, in part, be due to methods of assessment.This study used ecological momentary assessment to examine real-time associations between subjective mental sharpness and objective cognitive performance.Method: The sample included 162 older adults (M age = 71.78,SD = 5.01) enrolled in a clinical trial promoting memory strategies and healthy lifestyles.Participants endorsed concern about recent cognitive changes but performed within normal limits on cognitive screening.Using smartwatches, participants received four daily prompts to rate their mental sharpness (1-5 Likert scale), followed by an n-back task.Positive and negative affect were assessed daily.Bayesian mixed effects modeling quantified the strength of association between n-back performance and both average and momentary (deviations from one's own average) deviations in self-rated sharpness controlling for mood/affect, contextual factors, and practice effects.A secondary analysis investigated whether variability in performance was associated with any of the predictor variables.Results: There was an independent association between momentary deviations in mental sharpness on n-back performance (b = 0.041, 95% CI [0.008, 0.074]) such that when a participant's self-rated sharpness was below their personal average, cognitive performance was lower.Performance variability increased with age but was not strongly associated with self-reported sharpness.Conclusions: Ecological momentary assessment-captured momentary deviations in perceived sharpness predicted objective cognitive performance.Findings suggest that ecological momentary assessment methods could advance our ability to measure subjective cognitive ratings, with implications for detecting individuals at risk for developing dementia.