The treatment of sleep dysfunction to improve cognitive function: A meta-analysis of randomized controlled trials

This meta-analysis of randomized controlled trials (RCTs) evaluates if treating sleep disturbances improves cognitive function over at least 12 weeks. Multiple data sources were searched until November 1, 2021. RCTs were included if they examined the effect of an intervention (behavioral or medical) on sleep and cognition in an adult sample with sleep disturbances and had an intervention duration and follow-up of at least 12 weeks. Two independent reviewers located 3784 studies; 16 satisfied the inclusion criteria. Primary outcomes included the broad cognitive domains of visual processing, short-term memory, long-term storage and retrieval, processing speed, and reaction time. Most trials were conducted in participants with obstructive sleep apnea (OSA; N = 13); the most studied intervention was continuous positive airway pressure (CPAP; N = 10). All RCTs were 12 months in duration or less. The estimates of mean pooled effects were not indicative of significant treatment effect for any primary outcome. Although the interventions reduced daytime sleepiness (Hedge's g, 0.51; 95% confidence interval, 0.29–0.74; p < 0.01), this did not lead to cognitive enhancement. Overall, there was insufficient evidence to suggest that treating sleep dysfunction can improve cognition. Further studies with longer follow-up duration and supporting biomarkers are needed.