A Combined Intervention of Aerobic Exercise and Video Game in Older Adults: The Efficacy and Neural Basis on Improving Mnemonic Discrimination

Background: Mnemonic discrimination is very vulnerable to aging. Previous studies have reported that aerobic exercise and enriched cognitive stimulation (e.g., video games) could improve mnemonic discrimination in older adults. The animal model suggested that combining the 2 training methods could result in a larger improvement. However, there is limited evidence on the potential superior efficacy of combined intervention with human participants. Moreover, the neural basis of this potential superior is poorly understood. Methods: We conducted a 16-week intervention trial with 98 community-dwelling older adults assigned to one of the four groups (combined training, aerobic cycling alone, video game alone, or passive control). Mnemonic discrimination was measured as the primary behavioral outcome, hippocampal volume, and functional connectivity of the default mode network (DMN) were measured as neural indicators. Results: Participants receiving the combined intervention demonstrated the largest effect size of mnemonic discrimination improvement. Magnetic resonance image results indicated aerobic exercising increased left hippocampal volume, while video-game training counteracted the decline of DMN functional connectivity with aging. The synergy of hippocampal structural and functional plasticity observed in the combined training group explained why the largest intervention benefits were obtained by this group. Conclusion: Despite the nonrandomized design (i.e., likely self-selection bias), our results provide new evidence that combined intervention of exercise and cognitive training is more effective than single intervention for older adults. Parallel to animal studies, aerobic exercise and the video game with enriched cognitive stimulation could induce hippocampal plasticity through separate structural and functional pathways.