The Long-Term Efficacy of Working Memory Training in Healthy Older Adults: A Systematic Review and Meta-Analysis of 22 Randomized Controlled Trials

Objectives: The long-lasting efficacy of working memory (WM) training has been a controversial and still ardently debated issue. In this meta-analysis, the authors explored the long-term effects of WM training in healthy older adults on WM subdomains and abilities outside the WM domain assessed in randomized controlled studies. Method: A systematic literature search of PubMed, Web of Science, PsycINFO, Cochrane Library, ProQuest, clinicaltrials.gov, and Google Scholar was conducted. Random-effects models were used to quantitatively synthesize the existing data. Results: Twenty-two eligible studies were included in the meta-analysis. The mean participant age ranged from 63.77 to 80.1 years. The meta-synthesized long-term effects on updating were 0.45 (95% confidence interval = 0.253-0.648, <6 months: 0.395, 0.171-0.619, >= 6 months: 0.641, 0.223-1.058), on shifting, 0.447 (0.246-0.648, <6 months: 0.448, 0.146-0.75, >= 6 months: 0.446, 0.176-0.716); on inhibition, 0.387 (0.228-0.547, <6 months: 0.248, 0.013-0.484, >= 6 months: 0.504, 0.288-0.712); on maintenance, 0.486 (0.352-0.62, <6 months: 0.52, 0.279-0.761, >= 6 months: 0.471, 0.31-0.63). Discussion: The results showed that WM training exerted robust long-term effects on enhancing the WM system and improving processing speed and reasoning in late adulthood. Future studies are needed to use different tasks of the same WM construct to evaluate the WM training benefits, to adopt more ecological tasks or tasks related to daily life, to improve the external validity of WM training, and to identify the optimal implementation strategy for WM training.