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

Abstract

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.

European Respiratory Society guideline on non-CPAP therapies for obstructive sleep apnoea

“…Continuous positive airway pressure (CPAP) is the current standard of treatment of obstructive sleep apnoea (OSA), since its description in the early 1980s [1], and is highly effective in suppressing respiratory disturbances during sleep as well as improving several patient clinical manifestations [2][3][4][5][6][7][8]. However, advances in the pathophysiological understanding of OSA have shown that not only anatomical narrowing of the upper airways, but also impairment of muscle responsiveness, arousability and respiratory drive all contribute to the pharyngeal collapse that is the hallmark of the disorder [9,10].…”

The Link Between Obstructive Sleep Apnoea and Neurodegeneration and Cognition

“…Furthermore, in a meta-analysis based on 1926 subjects, M.L. reported that CPAP treatment (average treatment length: 6 weeks) had a (borderline) significant effect on attention and information processing speed in subjects with severe OSA, with no effects being identified for attention and speed of information processing, executive function, or memory [9]. After the onset of MCI, Richards et al found that subjects with MCI and mild OSA showed improved psychomotor/cognitive processing speed after 1 year of CPAP treatment [35,36].…”

“…Indeed, all but M.L. and Y. Wang (2020) reported a significant decrease in daytime sleepiness after treatment [8,9,33,34,36], although Bhat et al (2018) did not find changes in sleepiness to be predictive of improved vigilance [33]. However, older studies based on limited data have found that cognitive function did not improve after CPAP in subjects who did not experience subjective daytime sleepiness, irrespective of OSA severity [9,37].…”

“…Alternatively, oral devices or, in extreme cases, surgical procedures are available [2]. A growing body of evidence has shown the impact of OSA on reduced cognition [5][6][7][8][9], brain morphology [3,[10][11][12][13], and neurodegenerative pathophysiology [11,[14][15][16][17][18]. Furthermore, it has been shown that the treatment of OSA mitigates some of its negative consequences [13,16,[19][20][21], suggesting that, with readily available treatment options, OSA is a promising target to delay the onset of neurodegenerative disorders such as dementia, Alzheimer's disease (AD), or Parkinson's disease (PD).…”

‘One Size Doesn’t Fit for All’: There Is a Need for Targeted Personalized Therapy in Obstructive Sleep Apnea Syndrome

“…Continuous positive airway pressure (CPAP) has become the current gold standard of OSA treatment since the early 1980s [2]. CPAP has been proven to be highly effective in decreasing respiratory events during sleep and in improving the clinical manifestations of the disease [3][4][5]. However, almost 50% of the patients who are prescribed CPAP are not adherent to it at all or use it <4 h per night [6].…”