Cognitive and Exercise Training Improves Intraindividual Variability in Cognitive Performance in Older Adults: Secondary Findings of A Randomized Controlled Trial

Abstract

AbstractBackgroundIncreased intraindividual variability of cognitive performance is a marker of cognitive decline. Whether computerized cognitive training (CCT) and aerobic exercise counteracts cognitive decline by reducing intraindividual variability is unknown. We investigated the effects of CCT with or without aerobic exercise on reaction time intraindividual variability in older adults.MethodThis was a secondary analysis of an 8‐week randomized controlled trial. Older adults (aged 65‐85 years) were randomized to CCT alone (n = 41), CCT with aerobic exercise (n = 41), or an active control group (n = 42). The CCT group trained using the Fit Brains® platform 3×/week for 1 hour (plus 3×/week of home‐based training). The CCT with aerobic exercise group received 15 min of walking plus 45 min of Fit Brains® 3×/week (plus 3×/week of home‐based training). The control group received sham exercise and cognitive training (3×/week for 1 hour). We extracted reaction times from the Dimensional Change Card Sort Test, Flanker Inhibitory Control and Attention Test (Flanker), and Pattern Comparison Processing Speed Test (PACPS). Intraindividual variability was measured as residual intraindividual standard deviation (residual ISD) of raw reaction time latencies. Residual ISD is an unbiased measure of variability that accounts for within and between participant source of variation that could influence reaction time latencies. We also calculated reaction time intraindividual SD (raw‐score ISD) and intraindividual coefficient of variation (ICV).ResultCompared with the control group, residual ISD improved in a processing speed task (PACPS) following CCT alone (mean difference [95% confidence interval]: ‐0.147 [‐0.230 to ‐0.065], p<0.001) and CCT with aerobic exercise (‐0.111 [‐0.195 to ‐0.027], p<0.01). Also, for processing speed, both CCT (‐0.173 [‐0.261 to ‐0.084], p<0.001) and CCT with aerobic exercise (‐0.122 [‐0.213 to ‐0.032], p<0.01) showed greater reduction in raw‐score ISD compared with controls, while only CCT reduced ICV for this task (‐0.108 [‐0.176 to ‐0.040], p<0.001). Inhibitory attention (Flanker) improved only after CCT with aerobic exercise (congruent = ‐0.128 [‐0.250 to ‐0.006], incongruent = ‐0.121 [‐0.237 to ‐0.005], both p<0.05).ConclusionA CCT program promoted cognitive health via reductions in intraindividual variability of cognitive performance and combining it with aerobic exercise resulted in broader benefits.