The effect of combined cognitive intervention and physical exercise on cognitive function in older adults with mild cognitive impairment: a meta-analysis of randomized controlled trials

Background The state of mild cognitive impairment (MCI) provides an optimal window for preventing progression to dementia. Combined cognitive intervention and physical exercise may yield additive and synergistic effects on cognition in older adults with MCI. Objectives The purpose of this study was to assess the efficacy of a combined intervention to improve cognition in older adults with MCI by comparing a control group that underwent only cognitive intervention, a control group that underwent only physical exercise, and a control group that did not undergo cognitive intervention or physical exercise. Design Meta-analysis of randomized controlled trials (RCTs). Data sources The online databases of PubMed, Web of Science, Embase, the Cochrane Library, PsycINFO, and CINAHL were systematically searched. Review methods The outcomes were global cognition, memory, and executive function/attention. A sensitivity analysis was conducted when the I-2 statistic was > 50%. Results A total of 16 studies were included. The results showed that the combined intervention had positive effects on global cognition compared to the effects of the other control group [SMD = 0.27, 95% CI (0.09, 0.44), p = 0.003]. Regarding memory, the combined intervention had positive effects compared to the effects observed in the single physical exercise group [SMD = 0.25, 95% CI (0.07, 0.44), p = 0.006] and the other control group [SMD = 0.29, 95% CI (0.12, 0.47), p = 0.001]. For executive function/attention, the combined intervention had also positive effects compared to the effects of the single cognitive intervention group [SMD = 0.28, 95% CI (0.09, 0.47), p = 0.004], the single physical exercise group [SMD = 0.32, 95% CI (0.16, 0.49), p = 0.0002], and the other control group [SMD = 0.23, 95% CI (0.05, 0.41), p = 0.01]. Conclusions The combined intervention resulted in cognitive benefits in older adults with MCI and exhibited limited superiority over the single cognitive intervention and the single physical exercise on cognitive subdomains.