The impact of cognitive training and mental stimulation on cognitive and everyday functioning of healthy older adults: A systematic review and meta-analysis

•Cognitive training can improve older adults’ performance on cognitive tasks.•Interventions comprising general mental stimulation may benefit cognitive function but further research is required.•Effects of cognitive training can transfer to untrained tasks, untrained domains, and everyday functioning.•The effects of cognitive training can be maintained for up to six months.•Group cognitive training may have subjective and cognitive benefits over training in individual settings.

This systematic review and meta-analysis investigates the impact of cognitive training and general mental stimulation on the cognitive and everyday functioning of older adults without known cognitive impairment. We examine transfer and maintenance of intervention effects, and the impact of training in group versus individual settings. Thirty-one randomised controlled trials were included, with 1806 participants in cognitive training groups and 386 in general mental stimulation groups. Meta-analysis results revealed that compared to active controls, cognitive training improved performance on measures of executive function (working memory, p = 0.04; processing speed, p < 0.0001) and composite measures of cognitive function (p = 0.001). Compared to no intervention, cognitive training improved performance on measures of memory (face-name recall, p = 0.02; immediate recall, p = 0.02; paired associates, p = 0.001) and subjective cognitive function (p = 0.01). The impact of cognitive training on everyday functioning is largely under investigated. More research is required to determine if general mental stimulation can benefit cognitive and everyday functioning. Transfer and maintenance of intervention effects are most commonly reported when training is adaptive, with at least ten intervention sessions and a long-term follow-up. Memory and subjective cognitive performance might be improved by training in group versus individual settings.