Improved intraindividual variability in cognitive performance following cognitive and exercise training in older adults

Objective: Increased intraindividual variability (IIV) of cognitive performance is a marker of cognitive decline in older adults. Whether computerized cognitive training (CCT) and aerobic exercise counteracts cognitive decline by reducing IIV is unknown. We investigated the effects of CCT with or without aerobic exercise on IIV in older adults.Methods: This 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 (R) platform 3x/week for 1 hr (plus 3x/week of home-based training). The CCT with aerobic exercise group received 15 min of walking plus 45 min of Fit Brains (R) 3x/week (plus 3x/week of home-based training). The control group received sham exercise and cognitive training (3x/week for 1 hr). We computed reaction time IIV from the Dimensional Change Card Sort Test, Flanker Inhibitory Control and Attention Test (Flanker), and Pattern Comparison Processing Speed Test (PACPS).Results: Compared with the control group, IIV reduced in a processing speed task (PACPS) following CCT alone (mean difference [95% confidence interval]: -0.144 [-0.255 to -0.034], p < 0.01) and CCT with aerobic exercise (-0.113 [-0.225 to -0.001], p < 0.05). Attention (Flanker congruent) IIV was reduced only after CCT with aerobic exercise (-0.130 [-0.242 to -0.017], p < 0.05).Conclusions: A CCT program promoted cognitive health via reductions in IIV of cognitive performance and combining it with aerobic exercise may result in broader benefits.