Cognitive Effects of Treating Obstructive Sleep Apnea: A Meta-Analysis of Randomized Controlled Trials

Background: Obstructive sleep apnea (OSA) is associated with cognitive impairment and increased risks of dementia. However, the effect of continuous positive airway pressure (CPAP) on cognitive function in patients with OSA is still controversial. Objective: To evaluate the cognitive effects of CPAP treatment on OSA. Methods: We systematically searched PubMed, EMBASE, and Cochrane Library for randomized controlled trials (RCT) in the corresponding fields. Results: Totally 14 studies and 1,926 participants were included in our meta-analysis. Standardized mean difference (SMD) or weighted mean difference (WMD) were calculated for subjective sleepiness and cognitive domains including attention and speed of information processing, executive function, and memory. Individual cognitive scale and subgroup analyses according to OSA severity, length of trial, and RCT design type were further conducted. Significant treatment effect on attention and speed of information processing was only observed in severe OSA patients (SMD, 0.17; 95% CI, 0.02 to 0.31; p = 0.025; I-2 = 0%). Conclusions: Therefore, our meta-analysis indicates that CPAP treatment can partially improve cognitive impairment in the population of severe OSA.