A Model for Studying Neuropsychological Effects of Sleep Intervention: The Effect of 3-week Continuous Positive Airway Pressure Treatment

Screening for Obstructive Sleep Apnea in Adults: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

Obstructive sleep apnea (OSA) is associated with adverse health outcomes.

OBJECTIVE

To review the evidence on screening for OSA in asymptomatic adults or those with unrecognized OSA symptoms to inform the US Preventive Services Task Force.

DATA SOURCES

PubMed/MEDLINE, Cochrane Library, Embase, and trial registries through August 23, 2021; surveillance through September 23, 2022.

STUDY SELECTION

English-language studies of screening test accuracy, randomized clinical trials (RCTs) of screening or treatment of OSA reporting health outcomes or harms, and systematic reviews of treatment reporting changes in blood pressure and apnea-hypopnea index (AHI) scores.

DATA EXTRACTION AND SYNTHESIS

Dual review of abstracts, full-text articles, and study quality. Meta-analysis of intervention trials.

MAIN OUTCOMES AND MEASURES

Test accuracy, excessive daytime sleepiness, sleep-related and general health-related quality of life (QOL), and harms.

RESULTS

Eighty-six studies were included (N = 11 051). No study directly compared screening with no screening. Screening accuracy of the Multivariable Apnea Prediction score followed by unattended home sleep testing for detecting severe OSA syndrome (AHI ≥30 and Epworth Sleepiness Scale [ESS] score >10) measured as the area under the curve in 2 studies (n = 702) was 0.80 (95% CI, 0.78 to 0.82) and 0.83 (95% CI, 0.77 to 0.90). Five studies assessing the accuracy of other screening tools were heterogeneous and results were inconsistent. Compared with inactive control, positive airway pressure was associated with a significant improvement in ESS score from baseline (pooled mean difference, -2.33 [95% CI, -2.75 to -1.90]; 47 trials; n = 7024), sleep-related QOL (standardized mean difference, 0.30 [95% CI, 0.19 to 0.42]; 17 trials; n = 3083), and general health-related QOL measured by the 36-Item Short Form Health Survey (SF-36) mental health component summary score change (pooled mean difference, 2.20 [95% CI, 0.95 to 3.44]; 15 trials; n = 2345) and SF-36 physical health component summary score change (pooled mean difference, 1.53 [95% CI, 0.29 to 2.77]; 13 trials; n = 2031). Use of mandibular advancement devices was also associated with a significantly larger ESS score change compared with controls (pooled mean difference, -1.67 [95% CI, 2.09 to -1.25]; 10 trials; n = 1540). Reporting of other health outcomes was sparse; no included trial found significant benefit associated with treatment on mortality, cardiovascular events, or motor vehicle crashes. In 3 systematic reviews, positive airway pressure was significantly associated with reduced blood pressure; however, the difference was relatively small (2-3 mm Hg).

CONCLUSIONS AND RELEVANCE

The accuracy and clinical utility of OSA screening tools that could be used in primary care settings were uncertain. Positive airway pressure and mandibular advancement devices reduced ESS score. Trials of positive airway pressure found modest improvement in sleep-related and general health-related QOL but have not established whether treatment reduces mortality or improves most other health outcomes.

Associations Between Sleep Quality, Sleep Architecture and Sleep Disordered Breathing and Memory After Continuous Positive Airway Pressure in Patients with Obstructive Sleep Apnea in the Apnea Positive Pressure Long-term Efficacy Study (APPLES)

Objective

The role of sleep architecture in consolidation of memory has not been extensively investigated. In this study, the association of continuous positive airway pressure (CPAP) and sleep architecture and quality, and sleep disordered breathing on changes in memory are explored during the course of a 6 month clinical trial of CPAP or sham CPAP (APPLES).

Methods

848 participants had polysomnographic and memory assessments (Buschke Selective Reminding Test [Buschke] and Digit Symbol Substitution Test [DSST]) at baseline, CPAP/Sham CPAP titration, and the 2 and 6 month time points. Half were assigned to the CPAP and Sham CPAP groups respectively. Changes in performance on the Buschke and the DSST were analyzed over the course of the study between CPAP and Sham CPAP as well as in relationship to changes in sleep architecture, sleep quality and sleep disordered breathing (SDB).

Results

Sleep architecture, sleep quality and SDB improved in the CPAP group at 6 months; performance on the Buschke and DSST improved equally in both CPAP and Sham CPAP groups. There also were no significant correlations between changes in the amount or percentage of sleep stages between baseline and the 6 months, and corresponding changes in either the Buschke or the DSST. However, when stratified by the upper quartile and lower 3 quartiles, greater changes in the Buschke occurred over 6 months in the top quartile of total sleep time (5.7±7.3 vs. 4.0±6.8, p≤0.01) and amount of N3 sleep (55.9±7.7 vs. 53.6±8.9 min, p≤0.01). Those with more %N3 at 6 months scored better on the Buschke as well (55.9±7.8 vs. 53.6±8.9, p≤0.01). Borderline improvement in the DSST over 6 months was observed in the top quartiles of amount of N3 and %N3. Those in the top quartile of the amount of REM and %REM also showed greater improvement in the Buschke after 6 months. No differences were observed for the AHI, but those in the top quartile of oxygen desaturation had worse scores on the Buschke at 6 months. CPAP/Sham CPAP adherence did not impact 6 month Buschke or DSST performance.

Conclusions

CPAP improved long-term sleep duration, quality and architecture, but did not memory. However, large changes in REM and N3 sleep as well as moderate amounts of nocturnal hypoxemia are associated with changes in assessments of memory.

Continuous positive airway pressure treatment impact on memory processes in obstructive sleep apnea patients: a randomized sham-controlled trial

OBJECTIVE

The aim of this study was to investigate the changes in a large panel of memory processes after six weeks of continuous positive airway pressure (CPAP) in obstructive sleep apnea (OSA) patients. This randomized controlled trial compared the influence of effective CPAP to sham CPAP over six weeks on different memory processes in OSA patients.

METHODS

The study took place in a sleep laboratory and outpatient sleep clinic in a French tertiary-care university hospital. A total of 36 patients with OSA were randomized to receive either CPAP (n = 18) or sham CPAP (n = 18) for six weeks. Interventions were either effective CPAP or non-effective sham CPAP, for six weeks. All patients underwent an extensive battery of tasks evaluating three separate memory systems, before and after treatment. Verbal episodic memory was tested after forced encoding, procedural memory was tested using simplified versions of mirror drawing and reading tests, and working memory was examined with validated paradigms based on a theoretical model.

RESULTS

The study subjects were 55 ± 11 years of age and 72.2% were male. The mean body mass index was 29.5 ± 4.1 kg/m² and the apnea-hypopnea index was 37.1 ± 16.3/h. Prior to treatment, memory performances of OSA patients were altered. In an intention-to-treat analysis, memory deficits were not significantly improved after six weeks of effective CPAP compared to sham CPAP treatment. Verbal episodic, procedural, and working memory scores were comparable between both groups.

CONCLUSION

Using cautious methodology in comparing effective CPAP to sham CPAP and a well-defined set of memory assessments, we did not find improvement in memory performance after six weeks of treatment.

Effects of Continuous Positive Airway Pressure on Cognitive Deficits in Middle-aged Patients with Obstructive Sleep Apnea Syndrome: A Meta-analysis of Randomized Controlled Trials

BACKGROUND

Current views on continuous positive airway pressure (CPAP) treatment to improve the cognitive deficits of patients with obstructive sleep apnea syndrome (OSAS) are controversial, so we performed a meta-analysis.

METHODS

A comprehensive literature search was undertaken in PubMed, CINAHL, Medline, PsycInfo, EMBASE, Cochrane Library, CNKI, WanFang, VIP, and CBMdisc for studies published from June 1971 to July 2014. The outcome measures included neuropsychological tests of the 7 cognitive domains detailed below.

RESULTS

After screening the titles and abstracts and thoroughly reading the full text, we obtained 13 studies with little risk of bias that incorporated 1744 middle-aged obese participants with mild to severe OSAS. The studies were published from 1994 to 2012. Treatment durations varied from 1 to 24 weeks. The effect sizes of attention, vigilance, processing speed, working memory, memory, verbal fluency, and visuoconstructive skills domains were -0.10 (P = 0.24), -0.12 (P = 0.04), -0.08 (P = 0.16), 0.00 (P = 0.95), -0.04 (P = 0.30), -0.06 (P = 0.34), and -0.01 (P = 0.92), respectively.

CONCLUSIONS

Cognition partially improved in patients with OSAS after CPAP treatment. The only domain with significant improvement was vigilance. Rigorous randomized controlled trials need to be performed to obtain clear results.

Neuropsychological functioning after CPAP treatment in obstructive sleep apnea: a meta-analysis

The generally held clinical view is that treatment with continuous positive airway pressure (CPAP) improves cognition in patients with obstructive sleep apnea (OSA). However, the cognitive domains in which recovery is found differ between studies. A meta-analysis was conducted to quantify the effect of CPAP treatment in OSA on neuropsychological functioning. A literature search of studies published from January 1990 to July 2012 was performed. The inclusion criteria were: randomized controlled trial, diagnosis of OSA by poly(somno)graphy, apnea/hypopnea index, duration and compliance of CPAP treatment reported, use of one or more standardized neuropsychological tests. Mean weighted effect sizes of CPAP treatment for seven cognitive domains were calculated, including processing speed, attention, vigilance, working memory, memory, verbal fluency and visuoconstruction. Thirteen studies encompassing 554 OSA patients were included. A small, significant effect on attention was observed in favor of CPAP (d = 0.19). For the other cognitive domains the effect sizes did not reach significance. Improvement on measures of sleepiness was modest (d = 0.30-0.53) and comparable to prior research. In conclusion, this meta-analysis indicates that the effect of CPAP on cognition is small and limited to attention. Contrary to the general assumption, only slight improvement of neuropsychological functioning after CPAP treatment can be expected.