CPAP and behavioral therapies in patients with obstructive sleep apnea: Effects on daytime sleepiness, mood, and cognitive function

Summary

Obstructive sleep apnea (OSA) is a disorder characterized by repeated episodes of complete (apneas) or partial (hypopneas) cessations of breathing while sleeping. While continuous positive airway pressure (CPAP) treatment is commonly chosen to treat OSA, various conservative behavioral therapies are also used, particularly in patients unable to tolerate or benefit from CPAP or who have mild OSA. The principal purpose of these behavioral measures is to reduce risk factors which may underlie or exacerbate the disorder (e.g., weight reduction, smoking cessation, reduction/elimination of alcohol consumption, change in sleeping posture and sleep hygiene). Numerous studies have been conducted to evaluate the efficacy and/or effectiveness of CPAP in treating a wide range of OSA symptomatology. The present study consists of an exhaustive bibliographic search in Medline, PsycINFO, and Cochrane Review (1994–2007) databases and selection of works which have evaluated the efficacy and/or effectiveness of CPAP vis-a-vis daytime sleepiness, depression and cognitive functioning in OSA patients. The selected studies include randomized clinical trials in which CPAP was compared with more conservative measures, sham CPAP and oral placebos. The most important studies which evaluate the efficacy of behavioral treatments for OSA are also reviewed and the most remarkable results are presented. Various conclusions derived from the studies are discussed.

Introduction

Obstructive sleep apnea (OSA) is a relatively common disorder that can have wide ranging negative effects on physical health, daytime functioning, mood, and cognition. OSA is characterized by interruption of normal sleep by repetitive complete (apneas) and/or partial (hypopneas) cessations of breathing due to collapse of the upper airway. These episodes are commonly accompanied by oxyhemoglobin desaturation and result in fragmented sleep¹ and changes in sleep architecture. Stage 1, 3 and 4 sleep may be greatly reduced, with smaller but significant reductions in REM sleep2, 3 and stage 2 sleep is commonly longer than normal. In other words, sleep gets lighter and less restorative. The literature is mixed in terms of how these changes in sleep architecture relate to daytime sleepiness, mood, and cognition.4, 5

The effects of OSA on physical health, particularly cardiovascular functioning, are well-accepted. Unfortunately, many individuals with OSA go undiagnosed because they are not aware that their daytime symptoms might be due to OSA and, thus, do not discuss them with their physician. Some studies suggest that OSA prevalence is somewhere between 4 and 6% in middle-aged men, 2–4% in middle-aged women,6, 7 with higher rates in the elderly.6, 7

A typical OSA patient is a man who may be hypertensive, has been snoring for several years, has a family history of sleep and breathing disorders and, is often a consumer of sedative-hypnotics, alcohol and/or tobacco particularly before going to sleep.⁸ Thus, various health-related behaviors have been linked to OSA.

Various aspects of quality of life of OSA patients can be seriously affected, including diminished ability to execute various activities of daily living, depressed mood, and impaired cognitive functioning. Excessive daytime sleepiness (EDS) is a common and potentially serious sequela⁹ which may be a key factor in the increased occurrence of traffic accidents in OSA patients.10, 11, 12, 13 Thus, OSA can significantly impact various aspects of psychosocial functioning.

Continuous positive airway pressure (CPAP) treatment is the treatment of choice for OSA. However, some patients either cannot tolerate or do not seem to be helped by CPAP treatment, or have only mild OSA and prefer more conservative interventions. Thus, various behavioral treatments have also been used for this disorder.

The present review analyzes the therapeutic effectiveness of CPAP and behavioral treatments on the most important daytime symptomatology of OSA. For the purpose of this review, an exhaustive search in the Medline, PsycINFO and Cochrane Reviews (1994–2007) databases was conducted. We selected works which evaluated the efficacy and/or effectiveness of CPAP and behavioral therapies in treating daytime sleepiness, depressive symptomatology, and cognitive functioning in OSA patients. While space does not allow an exhaustive discussion of OSA studies, those having the most remarkable results are presented.