Effect of nasal continuous positive airway pressure on neuropsychological function in sleep apnea-hypopnea syndrome. A randomized, placebo-controlled trial

The additive value of continuous positive airway pressure treatment on psychological symptoms

OBJECTIVE

To screen psychological problems of patients with obstructive sleep apnea syndrome (OSAS) by utilizing the psychological symptom screening test Symptom Checklist-90-Revised (SCL-90-R) and to evaluate the effect of continuous positive airway pressure (CPAP) treatment.

METHODS

The SCL-90-R and Epworth Sleepiness Scale (ESS) test were applied to 66 patients with Apnea-Hypopnea Index (AHI ≥ 30/h) using CPAP device and 20 healthy individuals; the test results were compared.

RESULTS

The age of the patients ranged from 28 to 67 years, and the patient group comprised 54 males (81.8%) and 12 females (18.2%). The AHI scores ranged from 30.05 to 99.80, with a mean of 49.34 ± 21.40. Significant improvement was seen in 6 of the 11 SCL-90-R scores in CPAP-treated patients.

CONCLUSION

The authors conclude that the SCL-90-R test may be appropriate for evaluating the response to CPAP treatment in OSAS patients and monitoring the psychosocial effects of treatment.

The public health burden of obstructive sleep apnea

Obstructive sleep apnea (OSA) is the most common respiratory disorder of sleep. The vast majority (>80%) of adults with moderate to severe OSA remain undiagnosed. The economic costs associated with OSA are substantial for both the individual and society as a whole; expenses are likely to be underestimated given that the disease remains undiagnosed in such a large percentage of individuals. The economic burden of motor vehicle collisions related to OSA alone is significant; it is estimated that 810,000 collisions and 1400 fatalities from car crashes in the United States were attributable to sleep apnea in 2000. The many health consequences of OSA include daytime sleepiness, reduced quality of life, decreased learning skills, and importantly, neurocognitive impairments that include impaired episodic memory, executive function, attention and visuospatial cognitive functions. Untreated OSA leads to numerous medical problems such as cardiovascular diseases that can potentially increase healthcare utilization. Untreated patients with sleep apnea consume a disproportionate amount of healthcare resources, expenditures that decrease after treatment. The gold-standard management of OSA remains treatment with CPAP (Continuous Positive Airway Pressure), which is effective in eliminating sleep fragmentation and preserving nocturnal oxygenation, thereby improving daytime sleepiness and quality of life. However, its impacts in reversing neurocognitive function are still uncertain. A significant impediment to CPAP effectiveness is low adherence rates (ranges from 50% to 75%). It is commonly accepted that CPAP improves excessive drowsiness; hence meliorates attention, and accumulating data suggest that CPAP improves a variety of other outcomes such as the risk of motor vehicle crashes.

Does continuous positive airways pressure treatment improve clinical depression in obstructive sleep apnea? A randomized wait-list controlled study

BACKGROUND

Obstructive sleep apnea (OSA) is a highly prevalent sleep disorder that is associated with a range of adverse daytime sequelae, including significantly higher rates of clinical depression than is seen in the general community. Improvements in depressive symptoms occur after treatment of the primary sleep disorder, suggesting that comorbid depression might be an intrinsic feature of OSA. However, there are limited data on whether treatment for OSA in patients diagnosed with clinical depression improves mood symptoms meaningfully enough to lead to the remission of the psychiatric diagnosis.

METHODS

N = 121 untreated OSA patients were randomized to either continuous positive airway pressure (CPAP) treatment or waitlist control, and depressive symptoms, sleepiness and clinical depression (using a structured clinical interview) were assessed at baseline and 4 months. Linear and logistic regression analyses were conducted, controlling for baseline scores, stratification factors and antidepressant use.

RESULTS

Depressive symptoms (odds ratio [OR] = -4.19; 95% confidence interval [CI] = -7.25, -1.13; p = .008) and sleepiness (OR = -4.71; 95% CI = -6.26, -3.17; p < .001) were significantly lower at 4 months in the CPAP group compared to waitlist. At 4 months, there was a significant reduction in the proportion of participants in the CPAP group meeting criteria for clinical depression, compared to the waitlist controls (OR = 0.06, 95% CI = 0.01, 0.37; p = .002).

CONCLUSION

Treatment of OSA may be a novel approach for the management and treatment of clinical depression in those with comorbid sleep disordered breathing. Larger trials of individuals with clinical depression and comorbid OSA are needed.

Clarifying the role of sleep in depression: A narrative review

It has been established that 4.4 to 20% of the general population suffers from a major depressive disorder (MDD), which is frequently associated with a dysregulation of normal sleep-wake mechanisms. Disturbances of circadian rhythms are a cardinal feature of psychiatric dysfunctions, including MDD, which tends to indicate that biological clocks may play a role in their pathophysiology. Thus, episodes of depression and mania or hypomania can arise as a consequence of the disruption of zeitgebers (time cues). In addition, the habit of sleeping at a time that is out of phase with the body's other biological rhythms is a common finding in depressed patients. In this review, we have covered a vast area, emerging from human and animal studies, which supports the link between sleep and depression. In doing so, this paper covers a broad range of distinct mechanisms that may underlie the link between sleep and depression. This review further highlights the mechanisms that may underlie such link (e.g. circadian rhythm alterations, melatonin, and neuroinflammatory dysregulation), as well as evidence for a link between sleep and depression (e.g. objective findings of sleep during depressive episodes, effects of pharmacotherapy, chronotherapy, comorbidity of obstructive sleep apnea and depression), are presented.

Effects of continuous positive airway pressure on depression and anxiety symptoms in patients with obstructive sleep apnoea: results from the sleep apnoea cardiovascular Endpoint randomised trial and meta-analysis

BACKGROUND

Whether continuous positive airway pressure (CPAP) treatment can improve depression or anxiety symptoms in obstructive sleep apnoea (OSA) patients remains uncertain.

METHODS

Secondary analysis of the Sleep Apnea Cardiovascular Endpoints (SAVE) trial, combined with a systematic review of randomised evidence. The SAVE secondary analyses involved 2410 patients with co-existing moderate-severe OSA and established cardiovascular disease randomly allocated to CPAP treatment plus usual care or usual care alone and followed up for 3·7 (SD 1·6) years. We evaluated the effect of CPAP treatment on depression and anxiety caseness (scores ≥ 8 on the Hospital Anxiety and Depression Scale depression and anxiety subscales [HADS-D and HADS-A]) for OSA patients.

FINDINGS

CPAP treatment was associated with reduced odds of depression caseness (adjusted odds ratio [OR] 0·80, 95% confidence interval [CI] 0·65-0·98, P = 0·031) compared to usual care in the SAVE trial and the treatment effect was greater in those with pre-existing depression symptoms. A systematic review of 20 randomised trials including 4255 participants confirmed a benefit of CPAP in reducing depression symptoms in OSA patients: the overall effect (standardised mean difference) was - 0·18 (95% CI - 0·24 to - 0·12). No effect of CPAP treatment on anxiety caseness was found both in patients of the SAVE study (adjusted OR 0·98, 95% CI 0·78-1·24, P = 0·89) and the systematic review.

INTERPRETATION

CPAP reduces depression symptoms in patients with co-existing OSA and CVD independently of improvements in sleepiness.

Depression as a Manifestation of Obstructive Sleep Apnea

BACKGROUND

Obstructive sleep apnea (OSA) often results in a wide range of comorbid conditions, predominantly of the cardiovascular/respiratory, endocrine/metabolic, and neuropsychiatric symptoms. In view of the ambiguity of literature regarding the association between OSA and depression, we conducted this study to show any association between the two disorders.

OBJECTIVE

The aim of the study was to see the association between OSA and depression and to study the prevalence of OSA in patients suffering from depression.

METHODS

We performed polysomnography (PSG) studies of patients that were referred from various subspecialty clinics from July 2011 to August 2013. Psychiatric diagnosis was done using mini international neuropsychiatric interview plus scale. This was followed by application of Hamilton Depression Rating Scale (HAM-D). Standard methods of statistical analysis were used for data analysis.

RESULTS

Out of 182 patients who underwent PSG, 47 were suffering from depression with a mean age significantly more (P < 0.001) than that of other population (58.60 years vs. 53.60 years). In our 47 depressed patients, 44 (93.6%) had abnormal PSG. Based on apnea-hypopnea index score, 3 (6.8%) patients had mild, 18 (40.9%) had moderate, and 23 (52.3%) had severe OSA. The mean HAM-D score was significantly more in depression patients, (17. 35 ± 5.45) as compared to non depressive patents (8.64 ± 6.24) (P = 0.0001).

CONCLUSION

This study demonstrates significant overlap between the sleep apnea and depression. Health specialists need more information about screening for patients with OSA to ensure proper diagnosis and treatment of those with the condition. Most of the clinicians do not suspect this important comorbidity of depression in the beginning resulting in delayed diagnosis.

Asthma outcomes improve with continuous positive airway pressure for obstructive sleep apnea

BACKGROUND

Continuous positive airway pressure (CPAP) in asthma patients with concomitant obstructive sleep apnea syndrome (OSAS) seems to have a favorable impact on asthma, but data are inconsistent due to methodological limitations of previous studies.

METHODS

Prospective, multicenter study. We examined asthma outcomes after 6 months of CPAP in 99 adult asthma patients (mean age 57 years) with OSAS (respiratory disturbance index ≥20). Asthma control and quality of life were assessed with the Asthma Control Questionnaire (ACQ) and the Mini Asthma Quality of Life Questionnaire (MiniAQLQ), respectively. Data were analyzed by intention-to-treat basis.

RESULTS

The mean ± SD score of the ACQ decreased from 1.39 ± 0.91 at baseline to 1.0 ± 0.78 at 6 months (P = 0.003), the percentage of patients with uncontrolled asthma from 41.4% to 17.2% (P = 0.006), and the percentage of patients with asthma attacks in the 6 months before and after treatment from 35.4% to 17.2% (P = 0.015). The score of the mAQLQ increased from 5.12 ± 1.38 to 5.63 ± 1.17 (P = 0.009). There were also significant improvements in symptoms of gastroesophageal reflux and rhinitis, bronchial reversibility, and exhaled nitric oxide values (all P < 0.05). No significant changes were observed in drug therapy for asthma or their comorbidities nor in the patients' weight.

CONCLUSIONS

Asthma control (both actual and future risk), quality of life, and lung function improved after starting continuous positive airway pressure in asthmatics with moderate to severe obstructive sleep apnea syndrome.

Trends in CPAP adherence over twenty years of data collection: a flattened curve

BACKGROUND

Obstructive sleep apnea (OSA) is a common disorder, and continuous airway positive pressure (CPAP) is considered to be the gold standard of therapy. CPAP however is known to have problems with adherence, with many patients eventually abandoning the device. The purpose of this paper is to assess secular trends in CPAP adherence over the long term to see if there have been meaningful improvements in adherence in light of the multiple interventions proposed to do so.

METHODS

A comprehensive systematic literature review was conducted using the Medline-Ovid, Embase, and Pubmed databases, searching for data regarding CPAP adherence over a twenty year timeframe (1994-2015). Data was assessed for quality and then extracted. The main outcome measure was reported CPAP non-adherence. Secondary outcomes included changes in CPAP non-adherence when comparing short versus long-term, and changes in terms of behavioral counseling.

RESULTS

Eighty-two papers met study inclusion/exclusion criteria. The overall CPAP non-adherence rate based on a 7-h/night sleep time that was reported in studies conducted over the twenty year time frame was 34.1 %. There was no significant improvement over the time frame. Behavioral intervention improved adherence rates by ~1 h per night on average.

CONCLUSIONS

The rate of CPAP adherence remains persistently low over twenty years worth of reported data. No clinically significant improvement in CPAP adherence was seen even in recent years despite efforts toward behavioral intervention and patient coaching. This low rate of adherence is problematic, and calls into question the concept of CPAP as gold-standard of therapy for OSA.

Comparative efficacy of CPAP, MADs, exercise-training, and dietary weight loss for sleep apnea: a network meta-analysis

STUDY OBJECTIVE

To synthesize evidence from available studies on the relative efficacies of continuous positive airway pressure (CPAP), mandibular advancement device (MAD), supervised aerobic exercise training, and dietary weight loss in patients with obstructive sleep apnea (OSA).

DESIGN

Network meta-analysis of 80 randomized controlled trials (RCTs) short-listed from PubMed, SCOPUS, Web of science, and Cochrane register (inception - September 8, 2015).

PATIENTS

Individuals with OSA.

INTERVENTIONS

CPAP, MADs, exercise training, and dietary weight loss.

RESULTS

CPAP decreased apnea-hypopnea index (AHI) the most [by 25.27 events/hour (22.03-28.52)] followed by exercise training, MADs, and dietary weight loss. While the difference between exercise training and CPAP was non-significant [-8.04 (-17.00 to 0.92), a significant difference was found between CPAP and MADs on AHI and oxygen desaturation index (ODI) [-10.06 (-14.21 to -5.91) and -7.82 (-13.04 to -2.59), respectively]. Exercise training significantly improved Epworth sleepiness scores (ESS) [by 3.08 (0.68-5.48)], albeit with a non-significant difference compared to MADs and CPAP.

CONCLUSIONS

CPAP is the most efficacious in complete resolution of sleep apnea and in improving the indices of saturation during sleep. While MADs offer a reasonable alternative to CPAP, exercise training which significantly improved daytime sleepiness (ESS) could be used as adjunctive to the former two.

Meta-analysis of randomised controlled trials of oral mandibular advancement devices and continuous positive airway pressure for obstructive sleep apnoea-hypopnoea

Obstructive sleep apnoea-hypopnoea (OSAH) causes excessive daytime sleepiness, impairs quality-of-life, and increases cardiovascular disease and road traffic accident risks. Continuous positive airway pressure (CPAP) treatment and mandibular advancement devices (MAD) have been shown to be effective in individual trials but their effectiveness particularly relative to disease severity is unclear. A MEDLINE, Embase and Science Citation Index search updating two systematic reviews to August 2013 identified 77 RCTs in adult OSAH patients comparing: MAD with conservative management (CM); MAD with CPAP; or CPAP with CM. Overall MAD and CPAP significantly improved apnoea-hypopnoea index (AHI) (MAD -9.3/hr (p < 0.001), CPAP -25.4 (p < 0.001)). In direct comparisons mean AHI and Epworth sleepiness scale score were lower (7.0/hr (p < 0.001) and 0.67 (p = 0.093) respectively) for CPAP. There were no CPAP vs. MAD trials in mild OSAH but in comparisons with CM, MAD and CPAP reduced ESS similarly (MAD 2.01 (p < 0.001); CPAP 1.23 (p = 0.012). Both MAD and CPAP are clinically effective in the treatment of OSAH. Although CPAP has a greater treatment effect, MAD is an appropriate treatment for patients who are intolerant of CPAP and may be comparable to CPAP in mild disease.

Reconsidering first-line treatment for obstructive sleep apnea: a systematic review of the literature

BACKGROUND

Continuous positive airway pressure (CPAP) is typically recommended as first line therapy for obstructive sleep apnea, but the adherence rate of CPAP is problematic. This study's objective was to systematically review the literature relating to CPAP as first line therapy for OSA and compare it to surgical literature on the same topic.

METHODS

A systematic review was conducted according to PRISMA guidelines, examining Medline-Ovid, Embase, and Pubmed databases. The primary search objective was to identify all papers reporting the results of (1) randomized clinical trials (RCT) of CPAP for the treatment of adults with OSA; and (2) both randomized and non-randomized clinical trials and case series on the surgical treatment of OSA in adults. A PhD-level biostatistician first screened papers, and then those that met study criteria were retrieved and analyzed using standardized forms for each author. The primary outcomes were adherence rates of CPAP.

RESULTS

A total of 82 controlled clinical trials for CPAP and 69 controlled and non-controlled surgery trials were identified for analysis. Variation in CPAP use within reported RCT trials were identified, and the majority of patients in the studies would eventually be considered non-adherent to CPAP.

CONCLUSIONS

When considering the numerous patient-related factors that come into play when CPAP is prescribed, the concept of CPAP as gold-standard therapy for OSA should be reconsidered. In many cases surgery can provide a better overall outcome. This study's results suggest that certain patients with OSA may be managed more effectively with surgery than CPAP, without confounding issues of treatment adherence.

Comparison of the effects of continuous positive airway pressure and mandibular advancement devices on sleepiness in patients with obstructive sleep apnoea: a network meta-analysis

BACKGROUND

Excessive daytime sleepiness is the most important symptom of obstructive sleep apnoea and can affect work productivity, quality of life, and the risk of road traffic accidents. We aimed to quantify the effects of the two main treatments for obstructive sleep apnoea (continuous positive airway pressure and mandibular advancement devices) on daytime sleepiness and to establish predictors of response to continuous positive airway pressure.

METHODS

We searched MEDLINE and the Cochrane Library from inception to May 31, 2015, to identify randomised controlled trials comparing the effects of continuous positive airway pressure, mandibular advancement devices or an inactive control (eg, placebo or no treatment) on the Epworth Sleepiness Scale (ESS, range 0-24 points) in patients with obstructive sleep apnoea. We did a network meta-analysis using multivariate random-effects meta-regression to assess the effect of each treatment on ESS. We used meta-regression to assess the association of the reported effects of continuous positive airway pressure versus inactive controls with the characteristics of trials and their risk of bias.

FINDINGS

We included 67 studies comprising 6873 patients in the meta-analysis. Compared with an inactive control, continuous positive airway pressure was associated with a reduction in ESS score of 2·5 points (95% CI 2·0-2·9) and mandibular advancement devices of 1·7 points (1·1-2·3). We estimated that, on average, continuous positive airway pressure reduced the ESS score by a further 0·8 points compared with mandibular advancement devices (95% CI 0·1-1·4; p=0·015). However, there was a possibility of publication bias in favour of continuous positive airway pressure that might have resulted in this difference. We noted no evidence that studies reporting higher continuous positive airway pressure adherence also reported larger treatment effects (p=0·70).

INTERPRETATION

Continuous positive airway pressure and mandibular advancement devices are effective treatments for reducing daytime sleepiness in patients with obstructive sleep apnoea. Continuous positive airway pressure seemed to be a more effective treatment than mandibular advancement devices, and had an increasingly larger effect in more severe or sleepier obstructive sleep apnoea patients when compared with inactive controls. However, mandibular advancement devices are an effective alternative treatment should continuous positive airway pressure not be tolerated.

FUNDING

Swiss National Science Foundation and the University of Zurich Clinical Research Priority Program Sleep and Health.

Clinical effectiveness and cost-effectiveness results from the randomised controlled Trial of Oral Mandibular Advancement Devices for Obstructive sleep apnoea-hypopnoea (TOMADO) and long-term economic analysis of oral devices and continuous positive airway pressure

BACKGROUND

Obstructive sleep apnoea-hypopnoea (OSAH) causes excessive daytime sleepiness (EDS), impairs quality of life (QoL) and increases cardiovascular disease and road traffic accident risks. Continuous positive airway pressure (CPAP) treatment is clinically effective but undermined by intolerance, and its cost-effectiveness is borderline in milder cases. Mandibular advancement devices (MADs) are another option, but evidence is lacking regarding their clinical effectiveness and cost-effectiveness in milder disease.

OBJECTIVES

(1) Conduct a randomised controlled trial (RCT) examining the clinical effectiveness and cost-effectiveness of MADs against no treatment in mild to moderate OSAH. (2) Update systematic reviews and an existing health economic decision model with data from the Trial of Oral Mandibular Advancement Devices for Obstructive sleep apnoea-hypopnoea (TOMADO) and newly published results to better inform long-term clinical effectiveness and cost-effectiveness of MADs and CPAP in mild to moderate OSAH.

TOMADO

A crossover RCT comparing clinical effectiveness and cost-effectiveness of three MADs: self-moulded [SleepPro 1™ (SP1); Meditas Ltd, Winchester, UK]; semibespoke [SleepPro 2™ (SP2); Meditas Ltd, Winchester, UK]; and fully bespoke [bespoke MAD (bMAD); NHS Oral-Maxillofacial Laboratory, Addenbrooke's Hospital, Cambridge, UK] against no treatment, in 90 adults with mild to moderate OSAH. All devices improved primary outcome [apnoea-hypopnoea index (AHI)] compared with no treatment: relative risk 0.74 [95% confidence interval (CI) 0.62 to 0.89] for SP1; relative risk 0.67 (95% CI 0.59 to 0.76) for SP2; and relative risk 0.64 (95% CI 0.55 to 0.76) for bMAD (p < 0.001). Differences between MADs were not significant. Sleepiness [as measured by the Epworth Sleepiness Scale (ESS)] was scored 1.51 [95% CI 0.73 to 2.29 (SP1)] to 2.37 [95% CI 1.53 to 3.22 (bMAD)] lower than no treatment (p < 0.001), with SP2 and bMAD significantly better than SP1. All MADs improved disease-specific QoL. Compliance was lower for SP1, which was unpopular at trial exit. At 4 weeks, all devices were cost-effective at £20,000/quality-adjusted life-year (QALY), with SP2 the best value below £39,800/QALY.

META-ANALYSIS

A MEDLINE, EMBASE and Science Citation Index search updating two existing systematic reviews (one from November 2006 and the other from June 2008) to August 2013 identified 77 RCTs in adult OSAH patients comparing MAD with conservative management (CM), MADs with CPAP or CPAP with CM. MADs and CPAP significantly improved AHI [MAD -9.3/hour (p < 0.001); CPAP -25.4/hour (p < 0.001)]. Effect difference between CPAP and MADs was 7.0/hour (p < 0.001), favouring CPAP. No trials compared CPAP with MADs in mild OSAH. MAD and CPAP reduced the ESS score similarly [MAD 1.6 (p < 0.001); CPAP 1.6 (p < 0.001)].

LONG-TERM COST-EFFECTIVENESS

An existing model assessed lifetime cost-utility of MAD and CPAP in mild to moderate OSAH, using the revised meta-analysis to update input values. The TOMADO provided utility estimates, mapping ESS score to European Quality of Life-5 Dimensions three-level version for device cost-utility. Using SP2 as the standard device, MADs produced higher mean costs and mean QALYs than CM [incremental cost-effectiveness ratio (ICER) £6687/QALY]. From a willingness to pay (WTP) of £15,367/QALY, CPAP is cost-effective, although the likelihood of MADs (p = 0.48) and CPAP (p = 0.49) being cost-effective is very similar. Both were better than CM, but there was much uncertainty in the choice between CPAP and MAD (at a WTP £20,000/QALY, the probability of being the most cost-effective was 47% for MAD and 52% for CPAP). When SP2 lifespan increased to 18 months, the ICER for CPAP compared with MAD became £44,066. The ICER for SP1 compared with CM was £1552, and for bMAD compared with CM the ICER was £13,836. The ICER for CPAP compared with SP1 was £89,182, but CPAP produced lower mean costs and higher mean QALYs than bMAD. Differential compliance rates for CPAP reduces cost-effectiveness so MADs become less costly and more clinically effective with CPAP compliance 90% of SP2.

CONCLUSIONS

Mandibular advancement devices are clinically effective and cost-effective in mild to moderate OSAH. A semi-bespoke MAD is the appropriate first choice in most patients in the short term. Future work should explore whether or not adjustable MADs give additional clinical and cost benefits. Further data on longer-term cardiovascular risk and its risk factors would reduce uncertainty in the health economic model and improve precision of effectiveness estimates.

TRIAL REGISTRATION

This trial is registered as ISRCTN02309506.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 18, No. 67. See the NIHR Journals Library website for further project information.

Effect of treatment of obstructive sleep apnea on depressive symptoms: systematic review and meta-analysis

BACKGROUND

Obstructive sleep apnea (OSA) is associated with increased morbidity and mortality, and decreased quality of life. Treatment with continuous positive airway pressure (CPAP) or mandibular advancement devices (MADs) is effective for many symptoms of OSA. However, it remains controversial whether treatment with CPAP or MAD also improves depressive symptoms.

METHODS AND FINDINGS

We performed a systematic review and meta-analysis of randomized controlled trials that examined the effect of CPAP or MADs on depressive symptoms in patients with OSA. We searched Medline, EMBASE, the Cochrane Central Registry of Controlled Trials, and PsycINFO from the inception of the databases until August 15, 2014, for relevant articles. In a random effects meta-analysis of 19 identified trials, CPAP treatment resulted in an improvement in depressive symptoms compared to control, but with significant heterogeneity between trials (Q statistic, p<0.001; I(2) = 71.3%, 95% CI: 54%, 82%). CPAP treatment resulted in significantly greater improvement in depressive symptoms in the two trials with a higher burden of depression at baseline (meta-regression, p<0.001). The pooled standardized mean difference (SMD) in depressive symptoms with CPAP treatment in these two trial populations with baseline depression was 2.004 (95% CI: 1.387, 2.621), compared to 0.197 (95% CI: 0.059, 0.334) for 15 trials of populations without depression at baseline. Pooled estimates of the treatment effect of CPAP were greater in parallel arm trials than in crossover trials (meta-regression, p = 0.076). Random effects meta-analysis of five trials of MADs showed a significant improvement in depressive symptoms with MADs versus controls: SMD = 0.214 (95% CI: 0.026, 0.401) without significant heterogeneity (I(2) = 0%, 95% CI: 0%, 79%). Studies were limited by the use of depressive symptom scales that have not been validated specifically in people with OSA.

CONCLUSIONS

CPAP and MADs may be useful components of treatment of depressive symptoms in individuals with OSA and depression. The efficacy of CPAP and MADs compared to standard therapies for depression is unknown. Please see later in the article for the Editors' Summary.

Acute exacerbation of sleep apnea by hyperoxia impairs cognitive flexibility in Brown-Norway rats

STUDY OBJECTIVES

To determine whether learning deficits occur during acute exacerbation of spontaneous sleep related breathing disorder (SRBD) in rats with high (Brown Norway; BN) and low (Zucker Lean; ZL) apnea propensity.

DESIGN

Spatial acquisition (3 days) and reversal learning (3 days) in the Morris water maze (MWM) with polysomnography (12:00-08:00): (1) with acute SRBD exacerbation (by 20-h hyperoxia immediately preceding reversal learning) or (2) without SRBD exacerbation (room air throughout).

SETTING

Randomized, placebo-controlled, repeated-measures design.

PARTICIPANTS

14 BN rats; 16 ZL rats.

INTERVENTIONS

20-h hyperoxia.

MEASUREMENTS AND RESULTS

Apneas were detected as cessation of respiration ≥ 2 sec. Swim latency in MWM, apnea indices (AI; apneas/hour of sleep) and percentages of recording time for nonrapid eye movement (NREM), rapid eye movement (REM), and total sleep were assessed. Baseline AI in BN rats was more than double that of ZL rats (22.46 ± 2.27 versus 10.7 ± 0.9, P = 0.005). Hyperoxia increased AI in both BN (34.3 ± 7.4 versus 22.46 ± 2.27) and ZL rats (15.4 ± 2.7 versus 10.7 ± 0.9) without changes in sleep stage percentages. Control (room air) BN and ZL rats exhibited equivalent acquisition and reversal learning. Acute exacerbation of AI by hyperoxia produced a reversal learning performance deficit in BN but not ZL rats. In addition, the percentage of REM sleep and REM apnea index in BN rats during hyperoxia negatively correlated with reversal learning performance.

CONCLUSIONS

Acute exacerbation of sleep related breathing disorder by hyperoxia impairs reversal learning in a rat strain with high apnea propensity, but not a strain with a low apnea propensity. This suggests a non-linear threshold effect may contribute to the relationships between sleep apnea and cognitive dysfunctions, but strain-specific differences also may be important.

Immediate and Long-term Neurocognitive Outcome in Patients with Obstructive Sleep Apnea Syndrome After Continuous Positive Airway Pressure Treatment

Neurocognitive dysfunction is a major clinical consequence in patients with obstructive sleep apnea syndrome (OSAS). The effects of continuous positive airway pressure (CPAP) treatment, as the gold standard of treatment in OSAS, on this major complication are controversial. The duration and compliance of CPAP are thought to be important factors but evidence is lacking. This study is designed to evaluate the effects of immediate (one night), long-term (3 months) influence and the compliances of CPAP treatment on the neurocognitive function in OSAS patients. We enrolled newly diagnosed severe OSAS patients. Neurocognitive function test battery, CANTAB (Cambridge Neuropsychological Test Automated Battery), was performed before, one night and 3 months of CPAP treatment. Patients with CPAP compliance rate ≥ 70 % and < 50 % were grouped into good and poor adherence subjects, respectively. Fourteen patients were enrolled in final analyses. Six of them were in poor compliant group. Improvements in attention domain were found in all subjects after one-night treatment and maintained till three-month follow-up. Additional improvements in some attention performances and visual memory performances were gained only after three-month treatment. Significant changes of decision-making and response control function were found between good and poor compliance groups after three-month treatment. CPAP can improve some neurocognitive function at the very first day used. Longer treatment of CPAP can additionally improve some other neurocognitive functions. Compliance of CPAP has influence on the recovery of neurocognitive functions in patients with severe OSAS.

Comparative effectiveness research in obstructive sleep apnea: bridging gaps between efficacy studies and clinical practice

Comparative effectiveness research encompasses research that compares two interventions to each other, and takes place in real-world settings without strict inclusion and exclusion criteria, according to the established standard of care. There is a need for comparative evaluations of the treatments for obstructive sleep apnea, a disease associated with increased cardiovascular risk, stroke and metabolic derangement. This article reviews the recent, representative literature that addresses obstructive sleep apnea intervention and treatment, paradigms for diagnosis and randomized control trials addressing the efficacy of interventions, in an effort to demonstrate examples of both traditional observational and randomized control trials, as well as to illustrate the considerable overlap between some traditional studies and comparative effectiveness research. Despite methodological challenges, the potentially large clinical and public health impact of obstructive sleep apnea, accompanied by considerable cost, mandates that randomized controlled trials and comparative effectiveness research be systematically applied to identify both the efficacy and effectiveness of alternative diagnosis and treatment strategies.

Information processing speed in obstructive sleep apnea syndrome: a review

To provide a comprehensive review of studies on information processing speed in patients with obstructive sleep apnea syndrome (OSAS) as compared to healthy controls and normative data, and to determine whether continuous positive airway pressure (CPAP) treatment improves information processing speed. A systematic review was performed on studies drawn from Medline and PsycINFO (January 1990-December 2011) and identified from lists of references in these studies. After inclusion criteria, 159 articles were left for abstract review, and after exclusion criteria 44 articles were fully reviewed. The number of patients in the studies reviewed ranged from 10 to 157 and the study samples consisted mainly of men. Half of the studies reported that patients with OSAS showed reduced information processing speed when compared to healthy controls. Reduced information processing speed was seen more often (75%) when compared to norm-referenced data. Psychomotor speed seemed to be particularly liable to change. CPAP treatment improved processing speed, but the improvement was marginal when compared to placebo or conservative treatment. Patients with OSAS are affected by reduced information processing speed, which may persist despite CPAP treatment. Information processing is usually assessed as part of other cognitive functioning, not as a cognitive domain per se. However, it is important to take account of information processing speed when assessing other aspects of cognitive functioning. This will make it possible to determine whether cognitive decline in patients with OSAS is based on lower-level or higher-level cognitive processes or both.

Obstructive sleep apnea and other sleep-related syndromes

Obstructive sleep apnea syndrome (OSAS) is a common disorder characterized by repetitive episodes of breathing cessation due to complete or partial collapse of the upper airway therefore affecting ventilation. It is quite common, with a prevalence of about 2-4%, has a strong genetic component, and creates a proinflammatory state with elevated TNFα and other cytokines. If untreated, OSA can lead to significant neurological problems that include stroke, cognitive decline, depression, headaches, peripheral neuropathy, and nonarteritic ischemic optic neuropathy (NAION). Treatment reverses some of these neurological problems. Treatment includes continuous positive airway pressure and its variants, oral appliances, weight loss, upper airway surgery, and rarely maxillofacial procedures. Other sleep breathing disorders such as hypoventilation, central sleep apnea, complex sleep apnea, and Cheyne-Stokes respiration are less common and are sometimes associated with neuromuscular disorders causing diaphragmatic paralysis, but can also be seen in opiate exposure and severe obesity.

An official American Thoracic Society statement: continuous positive airway pressure adherence tracking systems. The optimal monitoring strategies and outcome measures in adults

BACKGROUND

Continuous positive airway pressure (CPAP) is considered the treatment of choice for obstructive sleep apnea (OSA), and studies have shown that there is a correlation between patient adherence and treatment outcomes. Newer CPAP machines can track adherence, hours of use, mask leak, and residual apnea-hypopnea index (AHI). Such data provide a strong platform to examine OSA outcomes in a chronic disease management model. However, there are no standards for capturing CPAP adherence data, scoring flow signals, or measuring mask leak, or for how clinicians should use these data.

METHODS

American Thoracic Society (ATS) committee members were invited, based on their expertise in OSA and CPAP monitoring. Their conclusions were based on both empirical evidence identified by a comprehensive literature review and clinical experience.

RESULTS

CPAP usage can be reliably determined from CPAP tracking systems, but the residual events (apnea/hypopnea) and leak data are not as easy to interpret as CPAP usage and the definitions of these parameters differ among CPAP manufacturers. Nonetheless, ends of the spectrum (very high or low values for residual events or mask leak) appear to be clinically meaningful.

CONCLUSIONS

Providers need to understand how to interpret CPAP adherence tracking data. CPAP tracking systems are able to reliably track CPAP adherence. Nomenclature on the CPAP adherence tracking reports needs to be standardized between manufacturers and AHIFlow should be used to describe residual events. Studies should be performed examining the usefulness of the CPAP tracking systems and how these systems affect OSA outcomes.

The effect of beverages varying in glycaemic load on postprandial glucose responses, appetite and cognition in 10-12-year-old school children

Reducing glycaemic index (GI) and glycaemic load (GL) inconsistently improves aspects of cognitive function and appetite in children. Whether altering the GL by lowering carbohydrate relative to protein and fat has a role in these effects is unknown. Therefore, we assessed the differential effects of beverages varying in GL and dairy composition on appetite, energy intake and cognitive function in children. A total of forty children (10–12 years) completed a double-blind, randomised, crossover trial, receiving three isoenergetic drinks (approximately 1100 kJ): a glucose beverage (GI 100, GL 65), a full milk beverage (GI 27, GL 5) and a half milk/glucose beverage (GI 84, GL 35). For 3 h post-consumption, subjective appetite and cognitive performance (speed of processing, memory, attention and perceptual speed) were measured hourly. At completion, each child was provided a buffet-style lunch and energy intake was calculated. Blood glucose was objectively measured using the Continuous Glucose Monitoring System. Blood glucose AUC values were significantly different between the drinks (P,0·001), but did not sustain above the baseline for 3 h for any drink. Mixed modelling revealed no effect of beverage on subjective appetite or energy intake. Participant sex and drink GL significantly interacted for short-term memory (P,0·001). When girls consumed either milk-containing beverage, they recalled 0·7–0·8 more words compared with 0·5 less words after the glucose drink (P#0·014). Altering GL of drinks by reducing carbohydrate and increasing protein did not affect appetite or cognition in children. Girls may demonstrate improved short-term memory after consuming beverages with higher protein and lower GL.

Mood Predicts Response to Placebo CPAP

Study Objectives. Continuous positive airway pressure (CPAP) therapy is efficacious for treating obstructive sleep apnea (OSA), but recent studies with placebo CPAP (CPAP administered at subtherapeutic pressure) have revealed nonspecific (or placebo) responses to CPAP treatment. This study examined baseline psychological factors associated with beneficial effects from placebo CPAP treatment. Participants. Twenty-five participants were studied with polysomnography at baseline and after treatment with placebo CPAP. Design. Participants were randomized to either CPAP treatment or placebo CPAP. Baseline mood was assessed with the Profile of Mood States (POMS). Total mood disturbance (POMS-Total) was obtained by summing the six POMS subscale scores, with Vigor weighted negatively. The dependent variable was changed in apnea-hypopnea index (ΔAHI), calculated by subtracting pre- from post-CPAP AHI. Negative values implied improvement. Hierarchical regression analysis was performed, with pre-CPAP AHI added as a covariate to control for baseline OSA severity. Results. Baseline emotional distress predicted the drop in AHI in response to placebo CPAP. Highly distressed patients showed greater placebo response, with a 34% drop (i.e., improvement) in AHI. Conclusion. These findings underscore the importance of placebo-controlled studies of CPAP treatment. Whereas such trials are routinely included in drug trials, this paper argues for their importance even in mechanical-oriented sleep interventions.

Cognition in obstructive sleep apnea-hypopnea syndrome (OSAS): current clinical knowledge and the impact of treatment

Obstructive sleep apnea-hypopnea syndrome (OSAS) is characterized by the presence of disordered breathing events that occur during sleep, as well as symptoms such as sleepiness and snoring. OSAS is associated with a number of adverse health consequences, and a growing literature focuses on its cognitive correlates. Although research in this field is mixed, multiple studies indicate that OSAS patients show impairment in attention, memory, and executive function. Continuous positive airway pressure (CPAP) is the most effective and widely used treatment of OSAS, and supplemental medications may supplement CPAP treatment to ameliorate associated symptoms. Here, we review the literature on OSAS and cognition, including studies that have investigated the impact of CPAP and stimulant medication on cognitive performance in patients with OSAS. In general, no consistent effect of CPAP use on cognitive performance was evident. This may be due, in part, to variability in study design and sampling methodology across studies. Studies of stimulant medications generally reported positive effects on cognitive performance. We conclude with a discussion of the mechanisms that have been proposed to explain cognitive dysfunction in OSAS and directions for future research.

Effects of exercise training associated with continuous positive airway pressure treatment in patients with obstructive sleep apnea syndrome

PURPOSE

The aim of this study was to evaluate the effects of a 2-month exercise training associated with continuous positive airway pressure (CPAP) treatment on the subjective and objective sleep measurements, quality of life, and mood in moderate to severe obstructive sleep apnea syndrome (OSAS) patients.

METHODS

Male patients were randomized into two treatment groups: CPAP (n = 19) and CPAP + exercise (n = 13). All patients completed 1 month of sleep hygiene, 2 months of treatment (CPAP or CPAP + exercise), and 1 week of washout (no treatment). Fletcher and Luckett sleep questionnaire, Epworth sleepiness scale, sleep diaries, polysomnography, SF-36 inventory of quality of life, Profile of Mood States (POMS) questionnaire, neck circumference, and body composition were evaluated. CPAP + exercise group also underwent cardiopulmonary exercise test before and after treatment.

RESULTS

Both treatments were effective in improving subjective sleepiness but CPAP + exercise treatment was more effective in maintaining this improvement after washout. No significant differences were found in most of the sleep parameters studied in both groups. CPAP + exercise group showed lower values of tension and fatigue on POMS and higher values of physical functioning, general health perception, and vitality on SF-36 after treatment.

CONCLUSIONS

A 2-month exercise training associated with CPAP treatment for OSAS patients has a positive impact on subjective daytime sleepiness, quality of life (physical functioning and general health perception), and mood state (tension and fatigue).

Obstructive sleep apnea syndrome: natural history, diagnosis, and emerging treatment options

Sleep apnea is an entity characterized by repetitive upper airway obstruction resulting in nocturnal hypoxia and sleep fragmentation. It is estimated that 2%-4% of the middle-aged population has sleep apnea with a predilection in men relative to women. Risk factors of sleep apnea include obesity, gender, age, menopause, familial factors, craniofacial abnormalities, and alcohol. Sleep apnea has been increasingly recognized as a major health burden associated with hypertension and increased risk of cardiovascular disease and death. Increased airway collapsibility and derangement in ventilatory control responses are the major pathological features of this disorder. Polysomnography (PSG) is the gold-standard method for diagnosis of sleep apnea and assessment of sleep apnea severity; however, portable sleep monitoring has a diagnostic role in the setting of high pretest probability sleep apnea in the absence of significant comorbidity. Positive pressure therapy is the mainstay therapy of sleep apnea. Other treatment modalities, such as upper airway surgery or oral appliances, may be used for the treatment of sleep apnea in select cases. In this review, we focus on describing the sleep apnea definition, risk factor profile, underlying pathophysiologic mechanisms, associated adverse consequences, diagnostic modalities, and treatment strategies.

Neural injury in sleep apnea

Sleepiness has long been recognized as a presenting symptom in obstructive sleep apnea syndrome, but persistent neurocognitive injury from sleep apnea has been appreciated only recently. Although therapy for sleep apnea markedly improves daytime symptoms, cognitive impairments may persist despite long-term therapy with continuous positive airway pressure. We know now that certain groups of neurons, typically those that are more metabolically active, are more vulnerable to injury than others. Animal models of sleep apnea oxygenation patterns have been instrumental in elucidating mechanisms of injury. The hypoxia/reoxygenation events result in oxidative, inflammatory, and endoplasmic reticulum stress responses in susceptible neural groups. With molecular pathways being fleshed out in animal models, it is time to carefully and systematically examine neural injury in humans and test the applicability of findings from animal models. To succeed, however, we cannot view sleep apnea as an isolated process. Rather, injury in sleep apnea is more likely the consequence of overlapping injuries from comorbid conditions. The progress in elucidating mechanisms of neural injury is palpable, and it now seems we indeed are closer to developing therapies to prevent and treat neural injury in obstructive sleep apnea.

Effect of CPAP treatment on residual depressive symptoms in patients with major depression and coexisting sleep apnea: Contribution of daytime sleepiness to residual depressive symptoms

BACKGROUND

Although extensive studies have indicated a relationship between obstructive sleep apnea (OSA) and depressive symptoms, the effect of continuous positive airway pressure (CPAP) treatment on residual depressive symptoms in patients with both major depressive disorder (MDD) and coexisting OSA has not been examined.

METHODS

Seventeen patients with continued MDD despite pharmacotherapy such as antidepressants and/or benzodiazepines, who also had comorbid OSA, were required to complete the Beck Depression Inventory (BDI), Hamilton Rating Scale for Depression (HRSD), and Epworth sleepiness scale (ESS) at the commencement of the study and then again after 2 months of CPAP treatment.

RESULTS

BDI and HRSD scores decreased from 19.7 to 10.8 and 16.7 to 8.0 after 2 months of CPAP treatment (both p<0.01). We also found significant correlations among the improvement rates in BDI, HRSD and ESS scores (R=0.86 and 0.75, both p<0.01). The mixed effect model demonstrated a significant ESS effect on BDI and HRSD.

CONCLUSIONS

The results suggest that MDD patients with residual depressive symptoms despite pharmacotherapy who also have symptoms of suspected OSA, such as loud snoring, obesity, and daytime sleepiness, should be evaluated for sleep apnea by polysomnography and treated with an appropriate treatment such as CPAP. CPAP treatment may result in a significant improvement of residual depressive symptoms due to the improvement of daytime sleepiness in these patients.

The new local coverage determination criteria for adherence to positive airway pressure treatment: testing the limits?

BACKGROUND

To our knowledge, the new local coverage determination (LCD) adherence criteria for continued reimbursement of continuous positive airway pressure after 90 days has heretofore not been validated, including the effects of the policy on care for patients with obstructive sleep apnea.

METHODS

We examined a retrospective database of 150 patients who received neuropsychologic testing prior to treatment and 3 and 6 months post treatment. We categorized participants using the new LCD criteria. Comparisons of neuropsychologic variables were made between adherent and nonadherent groups.

RESULTS

Fifty-five participants (37%) failed to meet the new criteria, although this number may not reflect the actual rates of adherence in clinical settings because some efforts beyond standard care were made to ensure adherence to treatment among many of the participants. Of the 50 patients who did not receive any special adherence intervention, only 28 (56%) met the criteria. On most measures, patients with poor adherence demonstrated neuropsychologic improvements similar to their adherent counterparts. Nonadherent patients realized additional improvements in working memory between 3 and 6 months post treatment.

CONCLUSIONS

This study highlights the potential effects of the new criteria for adherence on patients with obstructive sleep apnea and their clinical care. These data were taken from a study that was not designed to examine these criteria, so controlled trials are needed to better understand the effect of the guidelines on adherence and treatment outcomes.

TRIAL REGISTRATION

clinicaltrials.gov; Identifier: NCT00939601.

Evaluation of sham-CPAP as a placebo in CPAP intervention studies

STUDY OBJECTIVES

To evaluate the use of sham-continuous positive airway pressure (CPAP) treatment as a placebo intervention.

DESIGN AND SETTING

Analysis of polysomnograms performed in fixed order without sham-CPAP and on the first night of the sham-CPAP intervention in participants in the CPAP Apnea Trial North American Program (CATNAP), a randomized, placebo controlled trial evaluating the effects of CPAP treatment on daytime function in adults with newly diagnosed mild to moderate obstructive sleep apnea (apnea hypopnea index (AHI) 5-30).

PARTICIPANTS

The first 104 CATNAP participants randomized to the sham-CPAP intervention arm.

MEASUREMENTS AND RESULTS

Compared to the polysomnographic measures without sham-CPAP, the study on the first night with sham-CPAP had statistically significant differences that suggested a decrease in sleep quality: decreased sleep efficiency, increased arousal index, increased time in stage 1 NREM sleep, and prolonged latency to REM sleep. However, all of these differences had a relatively small effect size. Compared to the polysomnogram without sham-CPAP, the number of hypopneas on the sham-CPAP polysomnogram was significantly increased and the number of apneas significantly decreased. Relatively minor differences in AHI with and without sham-CPAP were present and were dependent on the criteria used to score hypopneas.

CONCLUSION

Comparison of polysomnograms with and without sham-CPAP revealed differences that, although statistically significant, were small in magnitude and had relatively low effect sizes suggesting minimal clinical significance. The results support the use of sham-CPAP as a placebo intervention in trials evaluating the effects of CPAP treatment in patients with obstructive sleep apnea.

CLINICAL TRIAL INFORMATION

This paper was a secondary analysis of clinical trial data. CATNAP: CPAP Apnea Trial North American Program, the trial from which the data were obtained, is registered with clinicaltrial.gov. Registration #NCT00089752.

How treatment affects cognitive deficits in patients with sleep disorders: methodological issues and results

Sleep disorders are frequently associated with impaired performance although the type and extent of cognitive deficits varies widely between different types of sleep disorders. Treatment is expected to ameliorate these deficits. However, cognitive functioning and its change with treatment depend on numerous factors. In this chapter we discuss methodological issues, including test selection, and person-specific, task-specific and environmental factors that influence cognitive functioning. In addition, features of study design and sampling strategies are discussed. The chapter ends with a short overview of routes by which treatment may affect cognition in sleep-disordered patients.

Sleep-disordered breathing and heart failure: focus on obstructive sleep apnea and treatment with continuous positive airway pressure

BACKGROUND

Among patients with heart failure, sleep-disordered breathing is a common problem, with a prevalence ranging from 24% to 76%. Encompassed within the general category of sleep-disordered breathing are 2 types of sleep apnea: obstructive sleep apnea (OSA) occurs when the oropharyngeal musculature relaxes, causing a collapse of the upper airway, and central sleep apnea occurs when the brain stem fails to stimulate breathing.

METHODS AND RESULTS

This article focuses on the relationship between heart failure and OSA, the treatment of OSA with continuous positive airway pressure (CPAP), and the role of CPAP in improving such effects of heart failure as ejection fraction, blood pressure, sympathetic activity, sleepiness, heart rate, and mortality.

CONCLUSIONS

It is important to distinguish the type of sleep-disordered breathing a patient may have. Further studies are needed to elucidate the effects of CPAP and other therapies.

Evaluation of sham non‐invasive ventilation for randomized, controlled trials in ALS

Non-invasive positive pressure ventilation (NIV) treatment of advanced respiratory insufficiency prolongs survival in ALS. To investigate the critical question of whether earlier initiation of NIV might provide additional benefit, a randomized trial with an appropriate placebo is needed. This study evaluated sub-therapeutic (sham) continuous positive airway pressure as a potential placebo. In a single-blind design, 40 ALS patients with forced vital capacity>50% were randomized to receive 30 seconds (s) of either active NIV, with 8 cm H2O inspiratory and 4 cm H2O expiratory pressure, or sham NIV with<1 cm of H2O continuous positive airway pressure at the mask. A questionnaire was then used to assess whether subjects thought that they had received a "real" or "pretend" treatment trial. The subjects' median age was 60.5 years, and 38% were female. Twelve of 20 subjects (60%) who received active NIV and 7 (35%) of the 20 subjects who received sham thought that they had tried the active treatment (p = 0.11). Only 8 (20%) of all subjects were confident about their determination that they had received "real" or "pretend" NIV. Thus, sub-therapeutic (sham) continuous positive airway pressure is a promising placebo control for NIV trials in ALS.

Recognizing and managing obstructive sleep apnea in primary care

OBJECTIVE

This review aims to impart information regarding recognition of obstructive sleep apnea (OSA) and associated excessive sleepiness (ES) in the primary care setting in order to provide optimal care to patients with this common but serious condition. This review will also discuss the prevalence and treatment of depression in patients with OSA.

DATA SOURCES

A MEDLINE search of articles published between 1990 and 2008 was conducted using the search terms obstructive sleep apnea AND excessive sleepiness, obstructive sleep apnea AND depression, and obstructive sleep apnea AND primary care. Searches were limited to articles in English concerned with adult patients.

STUDY SELECTION

In total, 239 articles were identified. Articles concerning other sleep disorders and forms of apnea were excluded. The reference lists of identified articles were searched manually to find additional articles of interest.

DATA SYNTHESIS

Primary care physicians can aid in the diagnosis of OSA and associated ES by being vigilant for lifestyle and physical risk factors associated with this condition. In addition, primary care physicians should maintain a high level of clinical suspicion when presented with illnesses that are commonly comorbid with OSA, such as psychiatric disorders and depression, in particular. Conversely, assessment of patients with OSA for common comorbidities may also improve a patient's prognosis and quality of life.

CONCLUSIONS

Primary care physicians play a vital role in recognizing OSA and ES. These clinicians are crucial in supporting their patients during treatment by ensuring that they have clear, concise information regarding available therapies and the correct application and maintenance of prescribed devices.

Treating obstructive sleep apnea in adults with epilepsy: a randomized pilot trial

OBJECTIVE

Small uncontrolled series suggest that treatment of obstructive sleep apnea (OSA) in patients with epilepsy may improve seizure control. Prior to conducting a definitive randomized controlled trial, we addressed critical design issues in a pilot study.

METHODS

We identified a cohort of adult patients with medically refractory epilepsy and coexisting OSA, documented by polysomnography (PSG). After an 8-week baseline period, subjects with OSA were randomized to therapeutic or sham continuous positive airway pressure (CPAP) for 10 weeks. Subjects maintained seizure calendars and antiepileptic drug dosages were held constant.

RESULTS

Sixty-eight subjects with suspected OSA were enrolled and 35 subjects randomized to therapeutic CPAP (22 subjects) or sham (13 subjects) CPAP. Male gender and an elevated sleep apnea questionnaire score were predictive of OSA on PSG. Nineteen subjects in the therapeutic group and all 13 subjects in the sham group completed the trial. Baseline apnea-hypopnea index (AHI) and CPAP adherence were comparable between groups. A significant reduction in AHI was observed in the therapeutic CPAP group as compared to the sham group. Subjects, study coordinators, and principal investigators were unable to predict treatment allocation.

CONCLUSIONS

This pilot study provided critical information related to study design and feasibility for planning a comprehensive trial to test the hypothesis that treating obstructive sleep apnea in patients with epilepsy improves seizure control.

Positive airway pressure treatment for obstructive sleep apnea

Positive airway pressure (PAP) is the treatment of choice for patients with moderate-to-severe obstructive sleep apnea (OSA). Randomized controlled trials have demonstrated that PAP can effectively reduce the apnea-hypopnea index and improve subjective and objective sleepiness. Some studies have also demonstrated benefits in sleep quality and quality of life for both the patient and bed partner. Observational studies have shown a reduction in the risk of cardiovascular events in OSA patients treated with PAP compared to untreated patients. Since continuous PAP (CPAP) treatment of OSA was described, additional modes of pressure delivery have been developed (bilevel PAP, autoadjusting PAP, flexible PAP). While none of the variants of PAP improves adherence in unselected patients compared to CPAP, individual patients may respond to a change in pressure mode. Attended PAP titration remains the standard of practice for selecting a treatment pressure. However, use of autotitrating PAP devices in the unattended setting can provide an effective titration alternative with careful patient selection and review of titration results. More choices of mask interface are now available to improve comfort and intervene for mask or mouth leaks. However, despite the increase in PAP treatment options, lack of acceptance and inadequate adherence to PAP therapy remain the major causes of treatment failure. Some studies suggest that heated humidification can improve PAP adherence, especially in patients with nasal congestion or dryness. A systematic approach to PAP treatment including education, objective adherence monitoring, early intervention for side effects, and telephone and clinic support is essential to optimize adherence.

Neurocognitive effects of obstructive sleep apnea syndrome

The nature of the neurocognitive deficits found in obstructive sleep apnea is still debatable. What is the extent of higher executive versus alertness-based cognitive dysfunction? Are cognitive impairments caused by nighttime hypoxemia or daytime sleepiness? This paper demonstrates the importance of a sound theoretical neurocognitive framework to be able to answer these questions. A strategy to assess executive function is proposed and illustrated with well-known neuropsychological tests. It seems that the pervasive effects of decreased alertness on higher cognitive functioning were not fully taken into account in those studies in which executive dysfunction has been found and has been related to prefrontal lobe damage caused by intermittent hypoxemia. Therefore, a basal slowing in information processing, primarily due to sleepiness, may explain most of the neurocognitive deficits in sleep apnea. This conjecture appears to be in agreement with recent functional MRI studies indicating sleep loss as the primary cause of neurocognitive deficits, more so than hypoxemia.

Continuous positive airway pressure treatment for sleep apnea in older adults

Daytime sleepiness and sleep disordered breathing are increased in older compared to middle-aged adults. The cognitive and cardiovascular sequelae associated with obstructive sleep apnea (OSA) have significant implications for the older adult who may already be suffering from chronic illness. Most of the evidence supporting the utilization of continuous positive airway pressure (CPAP) for the treatment of OSA has been generated from studies employing samples consisting predominately of middle-aged adults. To examine the efficacy of CPAP for the treatment of obstructive sleep apnea in older adults with an emphasis on adherence and related treatment outcomes, this paper reviews findings from clinical trials including older individuals as well as those specifically targeting this population. These studies have demonstrated that following CPAP therapy, older adults have increased alertness, improved neurobehavioral outcomes in cognitive processing, memory, and executive function, decreased sleep disruption from nocturia and a positive effect on factors affecting cardiac function, including vascular resistance, platelet coagulability and other aspects of cardiovascular health. Physiological differences in respiratory structure and function between younger and older adults of similar disease severity are believed to result in older individuals requiring titration at lower CPAP levels. Once initiated, CPAP treatment is tolerated by older adults, including those with Alzheimer's disease. Patterns of adherence in older individuals are consistent with that of middle-aged adults.

Nasal dilator strip therapy for chronic sleep-maintenance insomnia and symptoms of sleep-disordered breathing: a randomized controlled trial

To test the impact of nasal dilator strips (NDSs) on insomnia severity, sleep-disordered breathing (SDB) symptoms, sleep quality, and quality of life. Randomized, controlled trial of 4 weeks' duration. Community sample of nonobese, adults with a primary sleep complaint of chronic sleep-maintenance insomnia and mild to moderate SDB symptoms (treatment, n=42; control, n=38). Primary outcomes were four validated scales: Insomnia Severity Index (ISI), Pittsburgh Sleep Quality Index (PSQI), Functional Outcomes of Sleep Questionnaire (FOSQ), and Quality of Life Enjoyment and Satisfaction Questionnaire (QLESQ). Secondary outcomes were sleep indices, nonrestorative sleep ratings, and SDB symptoms, assessed retrospectively and prospectively. Both groups received nonspecific education about sleep disorders. Treatment group also received a brief SDB education and nasal strip instructions. At 4 weeks' follow-up, the treatment group demonstrated significant (p=.0001), large improvements in ISI and PSQI (mean Cohen's d=1.18) and significant (p<.02), medium-sized improvements in FOSQ and QLESQ (mean d=0.51) compared to small, nonsignificant changes in control group (Cohen's d range=0.36-0.09). Treatment group change scores among all four primary variables were significantly correlated (mean r=0.50, p=0.01). Secondary prospective and retrospective outcomes showed medium to large improvements in treatment compared to controls for sleep indices (mean d=0.52 vs 0.28), nonrestorative sleep ratings (mean d=0.69 vs 0.11), and sleep breathing symptoms (mean d=0.47 vs 0.09). Significance was obtained for prospective sleep indices (p=0.01), retrospective, and prospective nonrestorative sleep ratings (p=0.003, <0.05), and retrospective sleep breathing symptoms (p=0.03). SDB education and NDSs demonstrated therapeutic efficacy in a select sample of insomnia patients with SDB symptoms. Replication of results requires placebo controls and objectively confirmed SDB cases.