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•	Highlights
•	Introduction
•	Symptoms
•	Causes
•	Risk Factors
•	Prognosis
•	Diagnosis
•	Lifestyle Changes
•	Treatment
•	Other Treatments
•	Surgery
•	Resources
•	References

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•	Central sleep apnea
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Sleep apnea

Highlights

Sleep Apnea and Heart Disease

• Sleep apnea can increase the risk of stroke, even if patients do not have high blood pressure. A 2005 study in the New England Journal of Medicine (NEJM) suggested that patients with obstructive sleep apnea are twice as likely to have strokes as patients without apnea. The more severe the sleep apnea, the greater the risk.
• Many patients with heart failure also suffer from sleep apnea. Another 2005 NEJM study found that continuous positive airway pressure (CPAP) treatment does not improve survival for patients with heart failure and central sleep apnea.

Sleep Position and Sleep Apnea

• Sleeping on the back, instead of the side, is a major cause of sleep apnea. In a 2005 study, researchers observed positional sleep apnea in 49% of patients with mild sleep apnea.
• Young children (under age 3) with sleep apnea have more respiratory problems when they sleep on their back, indicates a 2006 study.
• Simple lifestyle techniques (pillows, tennis balls) that force people to sleep on their side can help reduce sleep apnea episodes.

Mouth Guards and Tongue Splints

CPAP is the best treatment for sleep apnea, but many patients find it uncomfortable and have trouble sticking to the therapy. As an alternative, some patients with mild-to-moderate sleep apnea use mouth guards or tongue splints. A 2006 review suggests that these dental devices help reduce apnea episodes in half of all treated patients. The researchers also found that, for many patients, oral devices work as well as surgery.

Pillar Implant Surgery

A relatively new surgical procedure, the pillar palatal implant, works well for treatment of mild-to-moderate sleep apnea and snoring, according to several 2006 studies. The 10-minute procedure is performed in a doctor’s office under general anesthesia and is much less invasive than uvulopalatopharyngoplasty (UPPP), the standard surgical treatment for sleep apnea.

Introduction

Sleep apnea is a disorder in which a person stops breathing during the night, perhaps hundreds of times, usually for periods of 10 seconds or longer and sometimes for as long as a minute. These gaps in breathing are called apneas. Apnea literally meaning absence of breath.

Sleep apnea is usually accompanied by snoring. People might not even know they have the condition. It inevitably causes daytime sleepiness.

Sleep apnea is grouped into three categories:

• Obstructive
• Central
• Mixed

There is also another, less severe form of obstructed breathing called upper airway resistance syndrome (UARS).

Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is the most common form of apnea. It occurs when tissues in the upper throat collapse at different times during sleep, thereby blocking the passage of air. In general, OSA occurs as follows:

• On its way to the lungs, air passes through the nose, mouth, and throat (the upper airway).
• Under normal conditions, the back of the throat is soft and tends to collapse inward as a person breathes.
• Dilator (widening) muscles work against this collapse to keep the airway open. Interference or abnormalities in this process cause air turbulence.
• If the tissues at the back of the throat collapse and become momentarily blocked, apnea occurs. Breath is temporarily stopped. In most cases the person is unaware of it, although sometimes they awaken and gasp for breath.
• In some cases, the interference is incomplete (called obstructive hypopnea) and causes continuous but slow and shallow breathing. In response, the throat vibrates and makes the sound of snoring. Snoring can occur whether a person breathes through the mouth or the nose. (Snoring also occurs without sleep apnea.)
• Apnea decreases the amount of oxygen in the blood, and eventually this lack of oxygen triggers the lungs to suck in air.
• At this point, the patient may make a gasping or snorting sound but does not usually fully wake up.

Obstructive sleep apnea is defined as five or more episodes of apnea or hypopnea per hour of sleep that occur in individuals who have excessive daytime sleepiness.

Central Sleep Apnea

Central sleep apnea is much less common. It is caused by some problem in the central nervous system, most likely a failure of the brain to signal the airway muscles to breathe. In such cases, oxygen levels drop abruptly and usually the sleeper wakes with a start. Often people with central sleep apnea recall waking up. They generally experience less sleepiness during the day than people with obstructive sleep apnea. Heart disease, and in particular heart failure, is the most common cause of central sleep apnea.

Mixed Apnea

Mixed apnea is the term used when the two apneas occur together.

Upper Airway Resistance Syndrome (UARS)

Upper airway resistance syndrome (UARS) is a condition in which patients snore, wake frequently during the night, and have excessive daytime sleepiness. However, UARS patients do not have the breathing abnormalities that characterize sleep apnea and they do not show a reduction in blood oxygen levels. Unlike apnea, UARS is more likely to occur in women than in men. Treatments are similar to those of sleep apnea. It is not known if UARS has any serious health complications.

Symptoms

People with sleep apnea usually do not remember waking up during the night.

Symptoms in Adults

Symptoms may include:

• Excessive daytime sleepiness
• Morning headaches
• Irritability and impaired mental or emotional functioning
• Snoring (bed partners may report very loud and interrupted snoring)
• Heartburn (acid back-up that causes heartburn may be responsible for some cases of sleep apnea)

Symptoms in Children

Sleep apnea occurs in about 2% of children. They may have symptoms that differ from adults, including:

• Longer total sleep time than normal in some children, especially obese children or those with severe apnea.
• Snoring. (An estimated 3 - 12% of all children snore. However, not all of them have sleep apnea.)
• More effort in breathing (flaring nostrils, heaving chests, sweating). The chest may have an inward motion during sleep.
• Behavioral difficulties without any obvious cause, such as hyperactivity and inattention. (Some patients may even be misdiagnosed with attention-deficit hyperactivity disorder.)
• Irritability
• Bed-wetting
• Morning headaches
• Failure to grow and gain weight

Causes

Any structural abnormality in the face, skull, or airways that causes some obstruction or collapse in the upper airways and reduces air pressure can produce sleep apnea syndrome. Abnormalities in tissues that lie between the back of the mouth and the esophagus (food pipe) are one of the most common structural causes of sleep apnea. Enlarged soft palates (the base of the tongue and surrounding throat walls) are also associated with many cases of sleep apnea.

Nerve, Metabolic, and Mechanical Abnormalities

Researchers have identified several physiologic abnormalities that may play a role in causing sleep apnea or in making it worse. These include an inability to regulate levels of carbon dioxide, impaired brain and nervous system responsiveness to various chemical messengers, and poor reflexes or muscle tone in the upper airways. The underlying reasons for these disturbances and their connection to apnea require further study.

Obesity

Obesity is strongly associated with sleep apnea and is a cause of it in some cases. Imaging scans have shown fatty cells clogging the throat tissue, which indicates that they narrow the airways. In one study, the more obese a person with sleep apnea was, the higher the pressure on the airway and therefore the greater the obstruction of the airway. (Obstructive sleep apnea may also contribute to obesity itself, however, since a sleepy person tends to be sedentary.)

Sleep Behaviors

Snoring. Chronic snoring itself may actually be a cause of sleep apnea. Over time, the vibrations and the increased pressure against the upper airways as snoring people inhale may cause the soft palate to lengthen. This stretched palate is more prone to collapse and obstruction.

It should be stressed that snoring is very common. Snoring occurs in about a third of the population, while apnea, according to one study, occurs in only 6%. Snoring, then, does not always cause apnea, nor is it always a sign of the respiratory disorder. Furthermore, while snoring is also associated with daytime sleepiness regardless of whether apneas are present, snoring alone does not appear to pose any major health risks.

Mouth Breathing. Some evidence suggests that a tendency to breathe through the mouth (rather than the nose) during childhood can actually produce structural changes in the face (longer face, narrow jaw, receding chin). Such facial characteristics may eventually put people at risk for sleep apnea.

Causes of Sleep Apnea in Small Children

Sleep apnea occurs in about 2% of children and can occur even in very young children. The most likely causes are the following:

• Facial or skull abnormalities in infants.
• Overgrown tonsils, adenoids, or both in small children. (Removal of tonsils or adenoids can free the airways and solve the problem.)
• Premature infants also commonly have a form of apnea that may be related to lung or nervous system problems.

Risk Factors

Gender. More men than women appear to have sleep apnea. In the U.S., about 4% of men and 2% of women between the ages of 30 - 60 meet the criteria for obstructive sleep apnea. Such people have at lease five episodes of apnea or hypopnea (shallow nighttime breathing) for each hour of sleep plus excessive daytime sleepiness. A much higher percentage has just one of these two conditions.

Sleep apnea actually may be underdiagnosed in women, particularly older women. In general, older women have the same incidence of sleep apnea as men their own age. It is not clear why apnea occurs more often in men than women before menopause and why prevalence equalizes after menopause. Men tend to have larger necks and to weigh more than women and women tend to gain weight and develop larger necks after menopause. However, studies have not found that these physical factors fully explain the differences in risk by gender in young adults or the increase in sleep apnea in postmenopausal women.

Age. Sleep apnea is most common and its symptoms are worse in middle-aged adults between 40 and 60 years old. Nevertheless, it affects people of all ages, including a small percentage of children.

Ethnicity. African Americans face a higher risk for sleep apnea than any other ethnic group in the United States. Other groups at increased risk include Pacific Islanders and Mexicans.

Being Obese

Obesity, especially having fat around the abdomen (the so-called apple shape), is a particular risk factor for sleep apnea, even in adolescents and children. However, many people with sleep-related breathing disorders, particularly women and small children, are not obese. Also, not all people who are obese have sleep apnea. Specific anatomical and physiological properties in the airways are more likely to be present in obese individuals with apnea.

Physical Characteristics

Having a Larger Neck. Having a large neck is a risk factor for sleep apnea. In fact, larger necks in men may be the primary reason for their higher risk for sleep apnea compared to women. A neck measurement of 17 inches or greater in men or at least 16 inches in women is one indicator that may suggest the condition. Postmenopausal women are more likely than younger women to have sleep apnea, in part because they tend to be heavier and have larger necks.

Specific Facial and Skull Characteristics. Structural abnormalities in the face and skull may be responsible for many cases of sleep apnea. These are likely to be the cause in many non-obese people with early-onset sleep apnea, particularly if they also have a family history of the problem.

Specific physical characteristics that may increase the risk for sleep apnea in both adults and children include:

• A long lower part of the face
• Brachycephaly, a birth defect in which the head tends to be shorter and wider than average
• A narrow upper jaw
• A receding chin
• An overbite
• A larger tongue

Characteristics in the Soft Palate. Some people have specific abnormalities in the soft area (palate) at the back of the mouth and throat that may lead to sleep apnea. These abnormalities include:

• The soft palate is stiffer, larger than normal, or both. An enlarged soft palate may be a significant risk factor for sleep apnea.
• The soft palate and the walls of the throat around it collapse easily.

Smoking and Alcohol Use

Smoking. Smokers are at higher risk for apnea. Those who smoke more than two packs a day have a risk 40 times greater than nonsmokers.

Alcohol. Alcohol use has been associated with apnea, although studies are mixed. A major survey reported that 53% of people who use alcohol to help fall sleep experience symptoms of sleep apnea. Another study found no relationship.

Medical Conditions Related to Sleep Apnea

Diabetes. Diabetes is associated with sleep apnea and snoring. It is not clear if there is an independent relationship between the two conditions or whether obesity is the only common factor.

Gastroesophageal Reflux Disease (GERD). GERD is a condition caused by acid backing up into the esophagus. It is a common cause of heartburn. GERD and sleep apnea often coincide. In one study, almost half of apnea patients had symptoms of GERD. Some experts suggest that the backup of stomach acid in GERD may produce spasms in the vocal cords (larynx), thereby blocking the flow of air to the lungs and causing apnea. Or, apnea itself may cause pressure changes that trigger GERD. Some evidence suggests that treating sleep apnea with continuous positive airway pressure (CPAP) may reduce GERD symptoms by nearly 50%. However, obesity is common in both conditions and may be the common factor. More research is needed to clarify the association.

Polycystic Ovary Syndrome (PCOS). In a 2000 study, women with PCOS were 30 times more likely than other premenopausal women to have obstructive sleep apnea and excessive daytime sleepiness. Women with PCOS produce high amounts of male hormones, particularly testosterone, which can cause obesity, facial hair, and acne. About half of PCOS patients also have diabetes. Obesity and diabetes are both associated with sleep apnea and may be the common factors.

Chronic Problems in the Upper Airways. A 2001 Swedish study found that people with respiratory tract disorders, including asthma, chronic bronchitis, or seasonal allergies, reported symptoms of sleep apnea more often than those without any of these ailments.

Hypothyroidism. In rare cases, hypothyroidism has been reported as possible cause of sleep apnea. In such cases, treating the thyroid condition improves the sleep apnea.

Prognosis

Sleep apnea has a strong association with several diseases, particularly those related to the heart and circulation.

Adverse Effects of Sleep Apnea on Heart and Circulation

Researchers are intensively investigating why a problem in the upper airways is associated with serious conditions of the heart and circulatory system. Here are some of their findings:

• Major known risk factors for hypertension and heart disease (obesity, smoking, and alcohol abuse) are associated with sleep apnea. These factors, however, do not explain all cases of higher heart-related risks in people with sleep apnea. For example, among overweight people, those who have sleep apneas have a greater risk of heart problems than those without them.
• When breathing stops during episodes of apnea, carbon dioxide levels in the blood increase and oxygen levels drop. This effect may trigger a cascade of physical and chemical events that can then increase risk for heart problems.
• Apnea also causes decreased levels of the gas nitric oxide (NO), a potent substance that causes blood vessels to be elastic and expand. NO plays a crucial role in blood pressure control and heart health.
• Apnea may also increase levels of a substance called angiotensin-converting enzyme (ACE), which is known to play a role in high blood pressure and congestive heart failure.
• Researchers have reported high levels of certain immune factors called tumor necrosis factor-alpha (TNF-alpha) and interleukin 6 (IL-6) in people with sleep apnea, particularly those who are obese. High levels of TNF-alpha and IL-6 produce a damaging inflammatory response, which can harm cells in the body, including those in the arteries. Elevated TNF-alpha may be associated with fatigue, shortness of breath, and a diminished heart-pumping action.

At this time, however, evidence of a clear causal relationship with any of these health problems is still weak. Some studies have found no significant independent risk for heart disease from obstructive sleep apnea. The following are some discussions on the possible effects of apnea on specific health problems.

High Blood Pressure. A number of studies have found a strong association between sleep apnea and high blood pressure (hypertension). (In the past, the link between sleep apnea and hypertension was thought to be due to obesity, a risk factor for both conditions, but more recent studies contradict that theory.) A 2000 study followed patients for 4 years; the more nightly apnea episodes they had in the first year, the more likely they were to develop hypertension by the fourth year. A weak, but still higher-than-normal association with high blood pressure has also been observed in those who snore, wake frequently during the night, or have mild sleep apnea.

A 2004 data analysis of over 200,000 patient records revealed that people who took both antidepressants and antihypertensives were 18 times more likely to be diagnosed with obstructive sleep apnea than those who did not take the medications. The probability was highest among adults aged 20-39 years. These drugs do not cause sleep apnea, but antidepressants may be prescribed to treat hypertensive patients’ complaints of fatigue even if sleep apnea is the real cause. The researchers recommended that patients being treated for high blood pressure, depression, and fatigue should also be evaluated for sleep apnea.

One way that apnea may directly affect blood pressure, regardless of other risk factors:

• Blood pressure fluctuates widely and suddenly in response to episodes of apnea and hypopnea (shallow nighttime breathing).
• Such fluctuations are possibly due to a sudden surge in the sympathetic nervous system, which controls involuntary muscle responses, importantly those in the blood vessels and heart, and may also play a role in sleep apnea.
• These fluctuations lead to transient constriction of blood vessels that, over time, could possibly lead to sustained hypertension and heart damage.
• Effective treatment of sleep apnea with continuous positive airway pressure (CPAP) may reduce blood pressure. Sleep apneas must be significantly reduced, however, to have any effect on blood pressure. Even a 50% reduction in apneas has no effect.

Coronary Artery Disease and Heart Attack. Sleep apnea has been associated with heart disease regardless of the presence of high blood pressure or other heart risk factors. In a 2001 study, researchers observed that the more episodes of apnea and hypopnea a patient had, the higher the risk for a heart attack. Many of the factors associated with stroke and sleep apnea (a risk for blood clots and narrowing of the arteries) may also increase the risk for heart attacks. Obstructive sleep apnea, however, may have other effects that increase the risk for heart problems:

• Some evidence suggests that obstructive apneas cause an increase in stiffness and inflammation in the arteries, which is now proving to be an important aspect of heart disease, particularly in older adults.
• A 2002 study reported that the white blood cells of patients with apnea have an increased number of proteins called adhesion molecules on their surface that may bind to the lining of blood vessels and cause inflammation. Increasingly, scientists believe that inflammation plays an important role in the development of coronary artery disease, heart attacks, and many other major ailments.

Stroke. Sleep apnea doubles the risk for stroke. The worse the sleep apnea, the greater the risk; moderate-to-severe obstructive sleep apnea can triple the risk of stroke. Sleep apnea is also associated with high blood pressure, a known risk factor for stroke. However, people who have sleep apnea, but not high blood pressure, are also still at increased risk for stroke. Sleep apnea in stroke patients is also associated with a higher risk for worse symptoms after a stroke, including delirium, depression, poor response to speech, and difficulty conducting daily chores.

• A 2000 study observed that blood becomes more viscous (stickier) in the morning in people with obstructive sleep apnea compared to people without the sleep disorder. Such "sticky" blood is more apt to form clots that can lead to strokes. To support this, another 2000 study reported that stroke victims with sleep apnea tended to have higher levels of the blood protein fibrinogen than stroke victims without sleep apnea. Fibrinogen is a factor in blood that causes it to clot. Higher levels of fibrinogen have been linked to both strokes and heart attacks.
• A 1998 study reported that the carotid artery, the major artery to the brain, is in far greater danger of becoming sclerotic (hardened and narrower) in people with obstructive sleep apnea than in the average person. People with both diabetes and sleep apnea are at particularly high risk for this effect.

Heart Failure. Studies suggest that 11 - 37% of patients with heart failure also have sleep apnea. Central sleep apnea is particularly linked with heart failure. The evidence for the association between heart failure and sleep apnea includes:

• High blood pressure, which is associated with sleep apnea, is a major cause of later heart failure.
• Sleep apnea reduces oxygen levels and causes abnormal changes in blood pressure and heart rate that add to the burden of the failing heart.
• Obstructive sleep apnea can affect breathing functions that are particularly harmful for patients with existing congestive heart failure.
• Sleep apnea is associated with poorer survival in patients with heart failure. Some studies have suggested that treating sleep apnea with CPAP may improve heart function in these patients. However, a 2005 New England Journal of Medicine study found that CPAP did not improve survival in patients with heart failure and central sleep apnea

Atrial Fibrillation. Sleep apnea is more common in people with atrial fibrillation (irregular heartbeat) than in patients with other heart conditions. In a 2005 study published in Circulation, 49% of patients with atrial fibrillation were at risk for developing apnea, compared with 32% of general cardiology patients. An earlier study indicated that patients with untreated obstructive sleep apnea may be at increased risk for recurrence of atrial fibrillation. Patients with atrial fibrillation who received CPAP treatment had a lower risk for recurrence.

Metabolic Syndrome. The metabolic syndrome (also called Syndrome X) is a cluster of abnormalities that cause insulin resistance. Some of these factors, including hypertension and obesity, are also associated with sleep apnea. A 2004 study found that metabolic syndrome was nine times more common among patients with obstructive sleep apnea, independent of obesity.

Sleep Apnea as a Cause of Obesity

When it comes to sleep apnea and obesity, it is not always clear which condition is responsible for the other. For example, obesity is often a risk factor and possibly a cause of sleep apnea, but it is also likely that sleep apnea increases the risk for weight gain. Some studies indicate that sleep apnea disrupts rapid eye movement (REM) sleep, which, in turn, increases the risk for obesity. Research indicates that animals deprived of REM sleep tend to eat more. People with apnea may also become too tired to exercise and so put on weight.

Other Adverse Effects on Health

Sleep apnea is associated with a higher incidence of many medical conditions, other than heart and circulation. The links between apneas and the conditions are unclear.

• Pulmonary hypertension.
• Asthma. Sleep apnea may worsen asthma symptoms and interfere with the effectiveness of asthma medications. Treating the apnea may help asthma control.
• Diabetes.
• Kidney failure.
• Peripheral nerve damage (tingling, pain, or numbness in the hands and feet).
• Liver damage in obese individuals with sleep apnea. Recent research suggests that severe apnea may increase the risk of liver disease regardless of weight.
• Seizures, epilepsy, and other nerve disorders. Sleep apnea appears to pose a particularly risk for nocturnal epilepsy, a condition in which seizures occur during sleep.
• Headaches. Some studies strongly suggest that for some people sleep disorders, including apnea, may be the underlying causes of some chronic headaches. In some patients with both chronic headaches and apnea, treating the sleep disorder has been known to cure the headache, even the very severe and disabling form known as a cluster headache.
• Irregular menstrual periods. This occurs in about 40% of premenopausal women. It is not clear how they are related, but one study reported that treating apnea helped normalize periods.
• High-risk pregnancies. Some evidence suggests that there are higher rates of pregnancy complications in women with sleep apnea.
• Eye disorders, including glaucoma, conjunctivitis, dry eye, and various other infections and irritations. Findings presented at the 2003 annual meeting of the American Academy of Ophthalmology suggested that patients with sleep apnea may be at increased risk for glaucoma and should be tested for this eye disease. A vision-damaging condition called intracranial hypertension has also been observed some patients with sleep apnea.

Effects on Emotions and Thinking in Adults

Mental Issues in Adults. Some studies have reported that older people with sleep apnea and daytime sleepiness have lower scores on tests for mental functions, such learning and attention. One expert suggested that treating sleep apnea in older patients may correct some cases of dementia that are caused by sleep disturbances. Elderly people with sleep apnea may also be more prone to depression.

Emotional Effects of Sleep Apnea. Studies report an association between severe apnea and psychological problems. In one study, 32% of patients had symptoms of depression. Sleep-related breathing disorders can also worsen nightmares and post-traumatic stress disorder. In one study, treatment of sleep apnea eased these complaints. Certainly, daytime sleepiness interferes with quality of life. It is also possible that severe emotional problems might worsen the apnea.

Effects on Bed Partners

Because sleep apnea so often includes noisy snoring, the condition can also adversely affect the sleep quality of a patient's bed partner. Spouses or partners may also suffer from sleeplessness and fatigue. In some cases, the snoring can disrupt relationships. Diagnosis and treatment of sleep apnea in the patient can help eliminate these problems.

Effects in Infants and Children

Failure to Thrive. Small children with undiagnosed sleep apnea may "fail to thrive," that is, they do not gain weight or grow at a normal rate and they have low levels of growth hormone. In severe cases, this may affect the heart and central nervous system. Most often sleep apnea in children is caused by overgrown tonsils or adenoid. Their removal often completely solves all of these problems, including resolution of sleep apnea and restoring weight gain and normal growth hormone levels.

Attention Deficits and Hyperactivity. Problems in attention and hyperactivity are common in children with sleep apnea. There is some evidence that such children may be misdiagnosed with attention-deficit hyperactivity disorder. Snoring, rather than sleepiness, is a stronger risk factor for hyperactivity in many of these children, especially boys under 8 years old. (Even children who snore and do not have sleep apnea may be at higher risk for poor concentration.)

Sleep Apnea and Automobile Accidents

Some researchers believe that sleepiness associated with sleep apnea is the greatest risk factor for car accidents. As many as 200,000 automobile accidents in the U.S. and 1,500 deaths from such accidents are caused by sleepiness. Studies continue to report that drowsy driving is as risky as drunk driving. Several studies have suggested that people with sleep apnea have two to three times as many car accidents, and five to seven times the risk for multiple accidents.

Diagnosis

Not all people with suspected sleep apnea require medical tests. Expensive diagnostic efforts are probably not required for individuals who have no other health risk factors and whose suspected apnea does not affect their quality of life or safety on the road.

Doctors, however, should order diagnostic sleep studies if:

• The patient has a serious medical condition that might be worsened or caused by sleep apnea. Such conditions include heart disease, high blood pressure, heart failure, diabetes, chronic headaches, epilepsy, obstructive lung disease, or severe acid reflux (GERD).
• A child who shows signs of sleep apnea also has attention deficit problems or fails to thrive.
• The sleep apnea is severe enough to impair quality of life, increase the risk for accidents, or both.

In some cases of an uncertain diagnosis, high-risk patients may need to consult a sleep specialist or go to a sleep disorders center. At most centers, patients undergo an in-depth analysis, usually supervised by a multi-disciplinary team of consultants who can provide both physical and psychiatric evaluations. Centers should be accredited by the American Academy of Sleep Medicine.

Medical and Sleep History

To help determine the presence of sleep apnea, the doctor will ask the following questions:

• Is the patient taking any medications?
• How many periods of sleepiness are there each day and when do they occur? (Patients with apnea often do not describe this symptom as feeling "sleepy." They are more apt to describe this feeling as "lack of energy" or "feeling tired all day.")
• How restful is sleep?
• Do headaches occur regularly in the morning?
• Is the patient taking or withdrawing from stimulants, such as coffee or tobacco?
• How much alcohol is consumed per day?
• Does the patient have any problems with mental or emotional functioning?
• Does the patient suffer from heartburn?
• What is the normal sleeping position (back, side, or stomach)?
• If there is a sleeping partner, does he or she complain about the patient's snoring or gasping for breath? (Many times it is useful to interview the bed partner.)

Keeping a Record of Sleep. To help answer these questions, the patient may need to keep a sleep diary. Every day for 2 weeks, the patient should record all sleep-related information, including responses to questions listed above described on a daily basis. Recording sleep behavior using an extended-play audio or videotape can be very helpful in diagnosing sleep apnea.

Physical Examination

To diagnose sleep apnea, the doctor will check for physical indications of sleep apnea, including:

• Abnormalities in the soft palate or upper airways, including enlarged tonsils
• Upper body obesity
• A wide neck measurement

Some evidence suggests that doctors may accurate identify nearly all cases of suspected sleep apnea using physical criteria, including taking measurements of body mass (the indication of obesity), neck circumference, and four areas inside the mouth.

Ruling Out Other Disorders

If sleep apnea is not obvious after a physical examination and history, the doctor will need to rule out any other problems. These include sleep disorders, (such as narcolepsy, insomnia, or restless legs disorder), or any medical or psychologic conditions (chronic fatigue syndrome, depression) that may be causing daytime sleepiness.

Polysomnography

Polysomnography is the technical term for an overnight sleep study that involves recording brain waves and other sleep-related activity. Polysomnography involves many measurements and is typically performed at a sleep center.

The patient arrives about 2 hours before bedtime without having made any changes in daily habits. Polysomnography electronically monitors the patient as he or she passes, or fails to pass, through the various sleep stages. Polysomnography tracks:

• Brain waves
• Body movements
• Breathing
• Heart rate
• Eye movements

Changes in breathing and blood oxygen levels are also recorded. In patients with suspected sleep apnea, the sleep expert will track instances of apnea and hypopnea that last longer than 10 seconds. In general, if there are more than five episodes per hour, apnea is significant and if there are more than 15, the condition is serious.

Overnight polysomnography has been the gold standard for diagnosing obstructive sleep apnea in both adults and children. It is very labor-intensive and expensive, however, and also misses snoring-induced arousals. It is not always covered by health insurance and some centers have waiting lists that are months long.

Home Diagnostic Portable Devices

A number of portable devices are available or being developed so that patients will have the convenience of being monitored at home. Experts hope that such monitors eventually will replace the need for overnight sleep clinics or the need for attended monitoring at home. Limited evidence exists, however, on the accuracy of many portable monitors. Patients with serious medical conditions, including heart failure or a history of stroke or respiratory failure, should not use home tests.

The following are descriptions of some home monitoring techniques.

Home Oximetry. Pulse oximetry is a procedure that determines if oxygen levels in the blood are low. This is called hypoxia. Normal levels during the night would generally rule out sleep apnea. With this procedure, a device called a pulse oximeter is attached to the patient's finger. The oximeter transmits red and infrared light through the capillaries in the finger. Part of the light waves is absorbed by hemoglobin, a molecule in the blood that carries oxygen. The ratio of the two light beams provides the measurement of oxygen. The test is not always accurate, however. A combination with polysomnography, especially heart rate measurements, may be best for diagnosing sleep apnea.

Home oximetry monitors are available to rule out sleep apnea but their accuracy is unclear. A 2003 study indicated that home oximetry alone was not very helpful in discriminating between patients with or without sleep apnea. Home oximetry however, may be helpful in identifying patients with unsuspected and seriously low oxygen levels.

Unattended Monitoring with Auto-CPAP. This method is a recent and simple method for detecting impaired breathing. It uses an auto-CPAP machine, which is programmed to apply pressure through the airways via a tube that attaches to a mask that fits the nose. A monitor is attached that digitizes and records on a computer all the information on any apnea episodes during sleep.

Nasal Pressure Recording. One promising technique uses a very simple prong device that attaches to the nostrils. A monitor records the airflow through the mouth and nose.

Peripheral Arterial Tonometry. An investigative technique called peripheral arterial tonometry measures changes in blood flow in the arteries of the finger tips during sleep. Such measurements are proving to be accurate in detecting sleep apnea in 80% of cases.

Measuring Sleepiness

The Epworth sleepiness scale uses a simple questionnaire to measure excessive sleepiness during eight situations.

Lifestyle Changes

Sleeping on the back causes sleep apnea in about half of all people with mild sleep apnea. Body position greatly affects the number and severity of episodes of obstructive sleep apnea, with at least twice as many apneas occurring in people who lay on their back as in those who sleep on their side. This may be due to the effects of gravity, which cause the throat to narrow when a person lies on the back. (Indeed, astronauts show a marked reduction in apneas and snoring in the weightlessness of space.) Positional sleep apnea affects people of all ages, including young children.

As a first step in dealing with sleep apnea, the patient should simply try rolling over onto the side. Patients who sleep on their backs and have 50 to 80 apneas per hour can sometimes nearly eliminate them when they shift to one side or the other. (Changing positions is less effective the more overweight a person is, but it still helps.)

Here are some suggestions that might help a person maintain a low-risk sleeping position:

• Sew a small pocket to the back of the pajamas and place a tennis ball or other small ball into it.
• A special pillow that helps to stretch the neck may reduce snoring and improve sleep for people with mild sleep apnea.
• One study suggested that sleeping in an upright position could improve oxygen levels in overweight people with sleep apnea. Elevating the head of the bed may help.

Nasal Strips

Over-the-counter nasal strips, such as the Breathe Right strip, or other devices that open the nostrils are inexpensive and useful to prevent snoring. They may significantly improve early-stage sleep in people with sleep disorders associated with nasal obstruction and help reduce morning tiredness. They are not intended as treatments for sleep apnea, however.

Weight Loss

All patients with obstructive sleep apnea who are overweight should attempt a weight-reducing program. Weight loss certainly reduces snoring in many people, sometimes stopping it completely. It also improves sleep and significantly reduces daytime sleepiness. A 2000 study suggested that people who lost 10% of body weight experienced an average 26% reduction in risk for developing sleep apnea in the first place. (Gaining 10% of their body weight, on the other hand, increased the odds of sleep apnea 6-fold.)

Smoking and Alcohol

• Smokers should quit, since smoking worsens apnea
• Alcohol should be avoided within 4 hours of sleep

Medications

In general, drugs have not been very beneficial except for specific situations. Medications that treat accompanying disorders associated with sleep apnea may be helpful. The following may be helpful for certain patients:

• Modafinil (Provigil), which is also used to treat narcolepsy, was approved by the FDA in 2004 as the first drug to treat the sleepiness associated with obstructive sleep apnea. However, Provigil is meant to be used in combination with -- not as a substitute for -- standard apnea treatments such as CPAP. Sleep experts stress that patients who take Provigil should adhere to CPAP treatment as the drug treats only the symptom of sleepiness, not the underlying health risks associated with sleep apnea.
• Thyroid hormone may help sleep apnea in those with low thyroid (hypothyroidism).
• Theophylline, a drug commonly used for asthma management, has shown promise in treating central sleep apnea in patients with heart failure.
• Omeprazole (Prilosec), a drug used for patients with severe heartburn, may help patients with both sleep apnea and gastroesophageal reflux disorder (GERD).

Note on Sedatives. Sedatives, narcotics, and anti-anxiety drugs can actually worsen the breathing disturbances and arousal conditions that occur with sleep apnea These substances cause the soft tissues in the throat to sag and diminish the body's ability to inhale. Apnea sufferers should never use sleeping pills or tranquilizers. Apnea patients undergoing surgery should be sure that their surgeons, anesthesiologists, and other doctors are aware of their sleeping disorder in considering sedatives, anesthetics, and medications taken to relieve pain due to surgery.

Treatment

Treatment for sleep apnea depends on the severity of the problem. Given data on the long-term complications of sleep apnea, it is important for patients to treat the problem as they would any chronic disease. Simply trying to treat snoring will not treat sleep apnea. Because of its association with heart problems and stroke, sleep apnea that does not respond to lifestyle measures should be treated by a doctor, ideally a sleep disorders specialist.

At this time, the most effective treatments for sleep apnea are devices that deliver slightly pressurized air to keep the throat open during the night. There are a number of such devices available.

Continuous Positive Airflow Pressure (CPAP)

The best treatment for severe obstructive and mixed sleep apnea is a system known as continuous positive airflow pressure (CPAP), sometimes referred to as nasal continuous positive airflow pressure (nCPAP). It is safe and effective in sleep apnea patients of all ages, including children. CPAP is not recommended for patients with mild apnea. Patients with apnea but no daytime sleepiness report little or no benefit from this treatment.

CPAP works in the following way:

• The device itself is a machine weighing about 5 pounds that fits on a bedside table.
• A mask containing a tube connects to the device and fits over just the nose.
• The machine supplies a steady stream of air through a tube and applies sufficient air pressure to prevent the tissues from collapsing during sleep.

Benefits of CPAP

Effects on Sleep and Wakefulness. A major 2003 analysis confirmed the benefits of CPAP on both objective and subjective measures of sleep. After using CPAP regularly many patients report the following benefits:

• Restoration of normal sleep patterns.
• Greater alertness and less daytime sleepiness.
• Less anxiety and depression and better mood.
• Improvements in work productivity.
• Better concentration and memory. Some adults with symptoms of attention deficit hyperactivity disorder have improved after CPAP treatments for apnea. In two studies, however, equal improvements were also observed in people on sham CPAP, suggesting that the actual cognitive benefits from CPAP may be modest.
• Patients' bed partners also report improvement in their own sleep when their mates use CPAP, even though objective sleep tests showed no real difference in the partners' sleep quality.

If patients do not experience less sleepiness after a period of time and are still complying with the regimen, then the airflow pressure may not be high enough. Patients may require retesting. Many patients report feeling more alert after CPAP treatments even if objective laboratory tests fail to show significant differences in the number of apneas and wake-up periods.

Protection from Accidents. Studies suggest that treatment with CPAP can reduce the risk for accidents. In a 2001 study, untreated patients had a risk for automobile accidents that was three times the risk in the general population. When these patients were treated, their risk fell to normal.

Effects on the Heart and Circulation. Evidence is mixed on whether CPAP treatment may reduce serious heart conditions. Early studies suggested that CPAP could improve heart function, lower blood pressure, and prevent new cardiac events (such as heart attacks) in patients with congestive heart failure and coronary artery disease. However, a 2005 study in the New England Journal of Medicine found that, while CPAP helped improve some heart disease symptoms, it did not affect overall survival in patients with heart failure and central sleep apnea. (Patients with heart failure often have central sleep apnea.)

It is also unclear whether CPAP improves blood pressure. A 2006 study of patients with high blood pressure and sleep apnea indicated that short-term (4 weeks) CPAP treatment has no significant effect on lowering blood pressure. (It is possible that longer-term treatment may be helpful.) Other studies have found blood pressure benefits from short-term CPAP treatment. Treatment for sleep apneas must be very effective, however, to have any benefits on blood pressure. Even a 50% reduction in apneas has no effect.

Effects on Other Medical Conditions. Some studies suggest other benefits with the use of CPAP:

• Fewer morning headaches
• Reduction in abdominal fat (abdominal fat has been related to a higher risk for diabetes and heart disease.)
• Lower blood sugar levels in patients with type 2 diabetes
• Improved thinking and concentration in people with impaired mental function from sleep apnea
• Modest lung improvement in patients with both apnea and chronic obstructive lung disease (such as emphysema)

Side Effects and Getting Used to the Device

CPAP works well for both adults and children, but many patients have problems getting used to the device. Unfortunately, CPAP devices are often cumbersome, which can lead to patients becoming discouraged and stopping treatment. All patients should be warned that the first few nights of CPAP therapy are unnerving. The device often produces anxiety, primarily because of the mask. Starting out with low pressure to get used to the mask may help. Patients may actually experience less sleep or sleep of a different quality in the beginning of treatment.

Nearly all patients complain about at least one side effect. Nearly half of complaints are related to the mask. Many of these problems can be reduced with a well-chosen mask that is comfortable and reduces leakage as much as possible. Common complaints include:

• Irritation in the nose and throat. The most common complaints are nasal congestion and sore or dry mouth, which are caused by leakage that dries the airway. (This may be severe in elderly people or patients who have had uvulopalatopharyngoplasty, a surgical treatment for sleep apnea. Such patients are more likely to stop using CPAP.) Chin straps, nasal salt water sprays, or humidifiers may prevent these side effects. Heated humidification devices are also now available for CPAP users.
• Excessive application of pressure making exhalation difficult.
• A feeling of claustrophobia is a major factor in noncompliance. This can be improved by may be a lightweight and transparent mask or with masks known as nasal pillows, which are used only around the nostrils.
• Up to 30% of patients experience irritation and sores over the bridge of the nose. Getting a properly fitted and cushioned mask can help reduce this effect.
• Eye irritation or conjunctivitis.
• Upper respiratory infections. It is very important to keep the unit clean.
• Patients may also experience temporary chest muscle discomfort, which is caused by an increase in lung volume.
• Severe side effects are very rare but may include heart rhythm disorders (arrhythmias), severe nose bleeding, and air pockets in the skull.
• In addition to initial difficulties with its use, the fixed CPAP needs to be periodically readjusted. Patients can be trained to adjust the CPAP at home, thereby avoiding trips to the sleep professional for machine adjustments and making the process more convenient.

Although studies have reported that long-term compliance with CPAP systems is low, with about one-third of patients giving up the treatment, recent information suggests that it is improving, probably due to better technologies and better education. Patient education and support groups, a dedicated nurse to ensure close follow-up of patients (particularly in the first 2 weeks of therapy), and ready access to doctors to make adjustments as needed have all been shown to greatly improve compliance. Not surprisingly, patients whose symptoms are noticeably relieved by the procedure early on are more likely to continue the therapy.

Other Devices to Improve Airway Pressure

Bilevel Positive Airway Pressure. Bilevel positive airway pressure (BPAP) systems may be particularly helpful for patients with coexisting lung disease and those with excessive levels of carbon dioxide. These devices have a sensing feature that helps determine and vary the appropriate pressure depending on whether a person is breathing in or out. Greater pressure is needed on inhalation and less on exhalation. These machines are more expensive than the CPAP and may not be covered by insurance.

Automatic Titrating (Auto)-CPAP Pressure Devices. Even more sophisticated systems are available called auto-CPAP devices, which automatically customize air pressure for the individual patient. They usually use one of three methods:

• Overall pressure is kept low until a specific problem is detected. At that time the pressure is automatically increased rapidly.
• Pressure is low when there are no problems but is raised gradually when they are detected.
• Pressure is gradually raised and lowered in response to problems or their absence. In addition, the device can change depending on problems within single breaths.

Brands include AutoAdjust, Virtuoso, and AutoSet. These devices are more expensive than those that provide continuous airflow. A 2003 study indicated that they may improve compliance, particularly in patients who require high CPAP use. They may be especially helpful for patients who require varying levels of pressure due to other conditions, such as seasonal allergies. They may also be useful as home diagnostic tools for sleep apnea. Auto-CPAP devices are not recommended for all patients, particularly those with heart failure or serious lung disease.

Other Treatments

Oral appliances, also called dental appliances or devices, may be an option for patients who cannot tolerate CPAP. The American Academy of Sleep Medicine recommends dental devices for patients with mild-to-moderate obstructive sleep apnea who are not appropriate candidates for CPAP or who have not been helped by it. (CPAP should be used for patients with severe sleep apnea whenever possible.)

Several different dental devices are available. A trained dental professional such as a dentist or orthodontist should fit these devices. Devices include:

• Mandibular advancement device (MAD). This is the most widely used dental device for sleep apnea. It is similar in appearance to a sports mouth guard. MAD forces the lower jaw forward and down slightly, which keeps the airway open.
• Tongue retraining device (TRD). This is a splint that holds the tongue in place to keep the airway as open as possible.

Patients fitted with one of these devices should have a check-up early on to see if it is working; short-term success usually predicts long-term benefits. It may need to be adjusted or replaced periodically.

Benefits of Mandibular Advancement Device

MAD and similar devices seem to offer the following benefits:

• Significant reduction in apneas for those with mild-to-moderate apnea, particularly if patients sleep either on their backs or stomachs. They do not work as well if patients lie on their side. The devices may also improve airflow for some patients with severe apnea.
• Improvement in sleep in many patients.
• Improvement and reduction in the frequency of snoring and loudness of snoring in most (but not all) patients.
• Higher compliance rates than with CPAP.

According to a 2006 review, dental devices help control sleep apnea in 52% of treated patients. A 2002 report indicated that long-term use of a dental device achieved an 81% success rate in apnea improvement, which was significantly higher than the 53% success rate noted for uvulopalatopharyngoplasty (UPPP), the standard surgical treatment. There were also few complications with the dental device.

Disadvantages of Dental Devices

Dental devices, including MAD, are not as effective as CPAP therapy. The cost of these devices tends to be high. Side effects associated with dental devices include:

• Nighttime pain, dry lips, tooth discomfort, and excessive salivation. In general, these side effects are mild, although over the long term nearly half of patients stop using dental devices because of them. Devices made of softer materials may produce fewer side effects.
• Permanent changes in the position of the teeth or jaw have occurred in some cases of long-term use. Patients should have regular visits with a health professional to check the devices and make adjustments.
• In a small percentage of patients, the treatment may worsen apnea. Patients should be monitored with polysomnography (sleep lab evaluation) before and after therapy and when apnea symptoms worsen or recur.

Orthodontal Treatments

An orthodontic treatment called rapid maxillary expansion, in which a screw device is temporarily applied to the upper teeth and tightened regularly, may help patients with sleep apnea and a narrow upper jaw. This nonsurgical procedure helps to reduce nasal pressure and improve breathing.

Surgery

Surgery is sometimes recommended, usually by throat specialists, for severe obstructive sleep apnea. A patient should be sure to seek a second opinion from a specialist in sleep disorders. Few randomized clinical trials, the gold standard of medical research, have been conducted to verify the long-term efficacy of sleep apnea surgery.

Uvulopalatopharyngoplasty (UPPP)

The Procedure. Surgery known as uvulopalatopharyngoplasty (UPPP) removes soft tissue on the back of the throat. Such tissue includes all or part of the uvula (the soft flap of tissue that hangs down at the back of the mouth) and parts of the soft palate and the throat tissue behind it. If tonsils and adenoids are present, they are removed. The surgery typically requires a stay in the hospital.

The Goal of Surgery. The goal of UPPP is threefold:

• Increase the width of the airway at the throat's opening
• Block some of the muscle action in order to improve the ability of the airway to remain open
• Improve the movement and closure of the soft palate

Success Rates. Success rates for sleep apnea surgery are rarely higher than 65% and often deteriorate with time, averaging about 50% or less over the long term. Few studies have been conducted on which patients make the best candidates. Some studies suggest that surgery is best suited for patients with abnormalities in the soft palate, which may or may not involve the tonsils. Results are poor if the problems involve other areas or the full palate. In such cases, CPAP is superior. In one study, sleeping on the side (rather than the back) after surgery significantly boosted success rates.

Complications. Uvulopalatopharyngoplasty is among the most painful treatments for sleep apnea, and recovery takes several weeks. It is recommended only for select patients with severe obstructive sleep apnea. The procedure also has a number of potentially serious complications. In fact, in one study, 42% of patients had complaints about the procedure. Some complications include:

• Infection. In one study this complication was so common that 40% of patients needed another operation because of it. Preventive antibiotics administered an hour before surgery can help reduce this risk.
• Impaired function in the soft palate and muscles of the throat.
• Mucus in the throat.
• Changes in voice frequency.
• Swallowing problems.
• Regurgitation of fluids through the nose or mouth.
• Impaired sense of smell.
• Failure and recurrence of apnea. In such cases, CPAP is often less effective afterward, although one study found that oral appliances may still help.

In one review of studies, 20% of patients who had UPPP required tracheostomy afterward. Most of these complications can be avoided with proper technique and experienced surgeons.

Laser-Assisted Uvulopalatoplasty (LAUP)

A variation on UPPP called laser-assisted uvulopalatoplasty (LAUP) is being increasingly performed to reduce snoring. It removes less tissue at the back of the throat than UPPP and can be done in a doctor's office. At this time, however, long-term success rates from LAUP are very modest, particularly for reducing apneas. Some doctors, in fact, are concerned that if LAUP eliminates snoring, then a diagnosis of apnea may be missed in patients who have the more serious condition.

More than 50% of patients complain of throat dryness after surgery. Throat narrowing and scarring have also been reported. In a minority of patients, snoring becomes worse afterward.

Pillar Palatal Implant

The pillar palatal implant is a noninvasive surgical treatment for mild-to-moderate sleep apnea and snoring. It helps reduce the vibration and movement of the soft palate. In this procedure, a doctor inserts 3 short pieces of polyester string into the soft palate. The procedure can be performed in a doctor’s office and takes about 10 minutes. Unlike uvulopalatopharyngoplasty (UPPP), the pillar procedure requires only local anesthesia. Studies indicate it works as well as UPPP, with less pain and quicker recovery time.

Tracheostomy

Tracheostomy used to be the only treatment for sleep apnea. It is quite straightforward:

• The surgeon makes an opening through the neck into the windpipe and inserts a tube.
• It is almost 100% successful, but it requires a quarter-size opening in the throat. This produces a number of medical and psychological problems associated with recovery.

Today, this operation is performed rarely, usually only if sleep apnea is life-threatening.

Radiofrequency Ablation

A technique called radiofrequency ablation uses radiofrequency energy to shrink tissues in the upper airways:

• The radio waves heat, stiffen, and shrink a small amount of tissue at the base of the tongue.
• The therapy takes about 20 minutes and can be done in a doctor's office.
• It typically requires 10 treatments within five or six sessions. (A newer form requires fewer treatment sessions, and it appears to be effective.)
• It is far less invasive than standard surgery and results in far less pain and fewer complications. Discomfort can be controlled with simple pain relievers.

Studies reporting significant improvement in reduced snoring and less daytime sleepiness for some patients although, as with other surgeries, the benefits may be short term in the majority of patients. It may be helpful for mild obstructive sleep apnea.

Other Procedures

Other surgical procedures may be appropriate to correct facial abnormalities or obstructions that cause sleep apnea. They may be used alone or combined with each other or with UPPP. They include:

• Tongue advancement, in which an opening is cut where the tongue joins the jawbone and the area is pulled forward.
• Genioplasty, which is plastic surgery on the chin.
• Hyoid surgery, in which the movable bone underneath the chin is moved forward, pulling the tongue muscle along with it.
• Maxillary or maxillomandibular advancement (MMA), which moves the upper (maxilla) and/or lower (mandible) jawbone forward. A survey of patients who had MMA found that the surgery changed their facial appearance, but most people thought it was a change for the better.
• Surgery for nasal obstructions (such as a deviated septum) that contribute to snoring and other symptoms.

Removing Adenoids and Tonsils in Children

Adenotonsillectomy, or surgical removal of the tonsils and adenoids, is a first-line treatment for children and adolescents with sleep apnea. It cures the condition in 75 - 100% of cases. Two studies, published in 2005, suggested that adenotonsillectomy can significantly improve quality of life for children with obstructive sleep apnea.

Complications include respiratory illness, which occurs in about 25% of children after the surgery. The highest risk for respiratory complications is associated with:

• Being under 3 years old
• Severe sleep apnea
• Heart complications
• Failure to thrive
• Obesity
• Prematurity
• Recent lung infections
• Certain facial structures
• Neuromuscular disease

The procedure may fail to improve apnea in some patients, such as those with very severe disease. Such children are candidates for continuous positive airway pressure (CPAP) therapy.

Removal of the tonsils and adenoids alone is not an effective treatment for adults with sleep apnea, although the procedure may be effective when combined with UPPP surgery.

Resources

• www.sleepapnea.org -- American Sleep Apnea Association
• www.nhlbi.nih.gov -- National Heart, Lung, and Blood Institute
• www.aasmnet.org -- American Academy of Sleep Medicine
• www.sleepfoundation.org -- National Sleep Foundation
• www.nhlbi.nih.gov/about/ncsdr -- National Center on Sleep Disorders Research
• www.sleepeducation.com -- Sleep Education from the American Academy of Sleep Medicine
• www.wfsrs.org -- World Federation of Sleep Research Societies

References

Bradley TD, Logan AG, Kimoff RJ, Series F, Morrison D, Ferguson K, et al. Continuous positive airway pressure for central sleep apnea and heart failure. N Engl J Med. 2005 Nov 10;353(19):2025-2033.

Campos-Rodriguez F, Grilo-Reina A, Perez-Ronchel J, Merino-Sanchez M, Gonzalez-Benitez MA, Beltran-Robles M, et al. Effect of continuous positive airway pressure on ambulatory BP in patients with sleep apnea and hypertension: a placebo-controlled trial. Chest. 2006 Jun;129(6):1459-1467.

Ferguson KA, Cartwright R, Rogers R, Schmidt-Nowara W. Oral appliances for snoring and obstructive sleep apnea: a review. Sleep. 2006 Feb 1;29(2):244-262.

Friedman M, Vidyasagar R, Bliznikas D, Joseph NJ. Patient selection and efficacy of pillar implant technique for treatment of snoring and obstructive sleep apnea/hypopnea syndrome. Otolaryngol Head Neck Surg. 2006 Feb;134(2):187-196.

Kushida CA, Littner MR, Hirshkowitz M, Morgenthaler TI, Alessi CA, Bailey D, et al. Practice parameters for the use of continuous and bilevel positive airway pressure devices to treat adult patients with sleep-related breathing disorders. Sleep. 2006 Mar 1;29(3):375-380.

Kushida CA, Morgenthaler TI, Littner MR, Alessi CA, Bailey D, Coleman J Jr, et al. Practice parameters for the treatment of snoring and Obstructive Sleep Apnea with oral appliances: an update for 2005. Sleep. 2006 Feb 1;29(2):240-243.

Mador MJ, Kufel TJ, Magalang UJ, Rajesh SK, Watwe V, Grant BJ. Prevalence of positional sleep apnea in patients undergoing polysomnography. Chest. 2005 Oct;128(4):2130-2137.

Marcus CL, Rosen G, Ward SL, Halbower AC, Sterni L, Lutz J, et al. Adherence to and effectiveness of positive airway pressure therapy in children with obstructive sleep apnea. Pediatrics. 2006 Mar;117(3):e442-e451.

Pereira KD, Roebuck JC, Howell L. The effect of body position on sleep apnea in children younger than 3 years. Arch Otolaryngol Head Neck Surg. 2005 Nov;131(11):1014-1016.

Yaggi HK, Concato J, Kernan WN, Lichtman JH, Brass LM, Mohsenin V. Obstructive sleep apnea as a risk factor for stroke and death. N Engl J Med. 2005 Nov 10;353(19):2034-2041.

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