A multi-timescale, multi-method perspective on older adult neurocognitive adaptability

Objective: Ethical and economic values compel us to improve the screening, monitoring, and enhancement of older adult neurocognitive adaptability. Diverse contemporary theoretical and empirical perspectives highlight the multi-timescale, multi-mechanistic nature of neurocognitive adaptability. Still lacking are frameworks and methodologies that demonstrate this convergence to allow for new paradigms that harness the clinical utility of neurocognitive adaptability. Method: We present a multi-method, multi-timescale analysis of neurocognitive adaptability in a group of healthy, community-dwelling older adults from the Victoria, British Columbia region. Each participant completed a 96-trial computerized cognitive flexibility task at 4 to 6 separate laboratory visits spanning about a month. This captured within-person changes at the within-occasion and across-occasion levels (timescales of seconds and days/weeks, respectively). We used standardized clinical assessments of cognitive reserve (i.e., estimated premorbid function) and conscientiousness (a personality dimension) as cross-sectional (time-invariant) predictors in multi-level linear regression to illustrate between-person differences in within-person cognitive performance trajectories. Results: Reserve predicted cognitive performance differences at the timescale of seconds (within occasions) but did not relate to differences at the timescale of days/weeks (across occasions); in contrast, conscientiousness predicted cognitive performance differences at both timescales. Distinct processes operating within the same task (stimulus-classification vs. set-shifting) improved with practice at discrepant rates. Conclusions: Neurocognitive adaptability is underlain by multiple biopsychosocial mechanisms. Certain widely-used clinical indices (e.g., of reserve or conscientiousness) may estimate distinct types of neurocognitive adaptability relevant to maintaining functional independence into old age. Our methodology and theoretical framework assume that neurocognitive adaptability unfolds at multiple hierarchical scales of time.