CDBC/BCAAN Research Bite: Originally emailed March 8, 2024

Adele Diamond’s group published a systematic mega-review of 179 studies up to 2015 (Diamond & Ling 2019) on intervention to improve EFs. Importantly, this paper required each study to have at least one behavioural measure, include a measure of generalization, include a control group, and not be purely correlational.

Mindful movement practices (e.g., taekwondo & t’ai chi) showed the strongest results for improving EFs. Mindful movement exercises did better than more sedentary mindful practices. 30-40 minute sessions were more helpful than those less than 30 minutes. School-based programs such as Promoting Alternative Thinking Strategies, the Chicago School Readiness Project, and Tools of the Mind came in second, and were particularly good for improving inhibitory control. Both types of approaches showed better results than computerized cognitive training (e.g., CogMed).

Some key principles the paper summarized:

1. EF can be improved.
2. Generalization to untrained tasks usually occurs for similar tasks, but rarely improves on unpracticed tasks. Broader transfer effects happen with practice of a wider range of skills.
3. EF training must include continued challenge, where the task adapts to keep challenging the person.
4. Effects can last over time, but generally grow smaller (use it or lose it).
5. Those with more EF challenges benefit the most from intervention.
6. More training is generally better, with the exception of aerobic exercises with no evidence of greater EF benefits from longer programs.
7. For the most part, length of the sessions matters, with sessions > 30 minutes showing better results than those less than 30 minutes.
8. Spaced (distributed) practice produces better long-term outcomes than massed practice.
9. Benefits are mostly clearly seen on complex, multi-component EF tasks

In addition, there seems to be strong evidence for the role of physical activity in improving EF in individuals with ADHD. A PLoS One meta-analysis (Song et al., 2023)   found a significant impact of physical interventions on inhibitory control, working memory and cognitive flexibility in children and teens with ADHD. While there was a benefit to all kinds of physical activity, results were in line with the first paper above in that moderate exercise and those which require adaptive/flexible skills, and which endure over time show the most promise.

UPDATE: ‘debate and request for further dialogue’ for the research from a group of researchers https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6969305/

References

Diamond, A. & Ling, D. S. (2019). Review of the evidence on, and fundamental questions about, efforts to improve executive functions, including working memory. In J. Novick, M.F. Bunting, M.R. Dougherty & R. W. Engle (Eds.), Cognitive and working memory training: Perspectives from psychology, neuroscience, and human development, (pp.143-431). New York, NY: Oxford University Press. (pdf)

Song, Y., Fan, B., Wang, C., & Yu, H. (2023). Meta-analysis of the effects of physical activity on executive function in children and adolescents with attention deficit hyperactivity disorder. PloS one, 18(8), e0289732. https://doi.org/10.1371/journal.pone.0289732