Snoring is the act of breathing through the open mouth in such a way as to cause a vibration of the uvula and soft palate, thus giving rise to a sound which may vary from a soft noise to a loud unpleasant sound. This most commonly occurs during sleep.
Sleep apnea (alternatively sleep apnoea) is a common sleep disorder characterized by brief interruptions of breathing during sleep. These episodes, called apneas, last 10 seconds or more and occur repeatedly throughout the night. People with sleep apnea partially awaken as they struggle to breathe, but in the morning they may not be aware of the disturbances in their sleep.
The most common type of sleep apnea is obstructive sleep apnea (OSA), caused by relaxation of soft tissue in the back of the throat that blocks the passage of air.
Central sleep apnea (CSA) is caused by irregularities in the brain's normal signals to breathe.
Some people with sleep apnea have a combination of both types.
Snoring
The cause of snoring is some kind of blockage in the breathing passage. Those blockages can be of many kinds, including tongue falling into the throat, allergies, throat weakness causing the throat to close during sleep, mispositioned jaw, fat gathering in, and around, the throat.
When the airflow in the breathing passage becomes irregular (because of the blockage) then the soft palate starts flapping. This flapping of the soft palate is what makes the snoring sound.
About four percent of men, and about eighteen percent of women suffer from snoring before the age of sixty. This is probably one of the most common dysfunctions known. Oddly, considering the loudness some snoring sounds can attain, most snorers do not hear themselves snoring.
Most of the time snoring is considered not dangerous, but if serious it can become a life threatening sickness called sleep apnea.
Even if snoring may not be detrimental to the snorer, it can cause the snorer's bedmate to lose sleep. Being sleepy all day long can also be life threatening for the person and those around them. Also, studies have shown that there is a psychological component in snoring which causes discomfort in any listener, depending on the loudness, tone, frequency, and other auditorial attributes of the snore. Studies have shown that there is a direct inverse relationship between snoring and frequency of sexual activity between married partners, meaning that there is generally less sexual activity if one of the partners is a heavy snorer.
Snoring cures almost all revolve around clearing the blockage in the breathing passage. This is the reason snorers are advised to lose weight (to stop fat from pressing on the throat), to stop smoking (smoking weakens and clogs the throat), and to sleep on their side (to prevent the tongue from blocking the throat). But for many snorers those pieces of advice are not enough.
Surgery is one option to cure snoring (for example a uvulopalatopharyngoplasty); dental appliances such as a mandibular advancement splint are another. There are many devices such as nose clips to keep the nose open and jaw mechanics to keep the jaw in the right position. Different aids work for different people.
There is also a less known, but very effective way to stop snoring. It is to exercise the throat, the tongue, and the jaw muscles so the breathing passage will widen and stay open when you sleep. Singing and practicing yoga may be other ways to stop snoring.
Sleep Apnea
The hallmark symptom of the disorder is excessive daytime sleepiness. Additional symptoms of sleep apnea include restless sleep, loud snoring (with periods of silence followed by gasps), falling asleep during the day, morning headaches, trouble concentrating, irritability, forgetfulness, mood or behavior changes, anxiety, and depression. Sleep apnea is more likely to occur in men than in women, and in people who are overweight or obese.
Most people with sleep apnea have obstructive apnea, in which the person stops breathing during sleep due to airway blockage. Sufferers usually resume breathing within a few seconds, but periods of as long as sixty seconds are not uncommon in serious cases. It is more common amongst people who snore, who are obese, who consume alcohol, or who have anatomical abnormalities of the jaw or soft palate. However, atypical cases do occur, and the condition should not be ruled out unilaterally merely because the patient does not fit the profile.
Obstructive Sleep Apnea (OSA) is caused by the relaxation of the muscles in the airway during sleep. Whilst the vast majority of people successfully maintain a patent (open) upper airway and breathe normally during sleep, a significant number of individuals are prone to severe narrowing or occlusion of the pharynx, such that breathing is impeded or even completely obstructed. As the brain senses a build-up of carbon dioxide, airway muscles are activated which open the airway, allowing breathing to resume but interrupting deep sleep.
Recurrent airway obstruction gives rise to the obstructive sleep apnea syndrome, the most common category of sleep-disordered breathing, with 2% of female and 4% of male subjects meeting the minimal diagnostic criteria for OSA of at least 10 apneic events per hour. An "event" can be either an apnea, characterised by complete cessation of airflow for at least 10 seconds, or a hypopnea in which airflow decreases by 50 percent for 10 seconds or decreases by 30 percent if there is an associated decrease in the oxygen saturation or an arousal from sleep. To grade the severity of sleep apnea the number of events per hour is reported as the apnea-hypopnea index (AHI). An AHI of less than 5 is considered normal. An AHI of 5-15 is mild; 15-30 is moderate and more than 30 events per hour characterizes severe sleep apnea.
These recurrent episodes of airway obstruction are associated with asphyxia, hypertension, depression, and daytime fatigue, since a transient interruption of the sleep cycle accompanies the restoration of airway patency. Most sufferers are not aware of these events, and are informed of the symptoms by their sleep partner. The apneic episodes are thought to account for the clinical sequelæ (symptoms that arise from a particular condition), which include increased incidence of chronic hypertension, a 700% rise in road traffic accidents, excessive daytime somnolence (similar, but unrelated to narcolepsy), social and family disruption, and cardiac arrhythmias and morbidity . Obstruction of the upper airway may also be a cause of or may contribute to sudden infant death syndrome (SIDS).
Diagnosis
The typical patient with sleep apnea is an overweight middle-aged male with a neck size of more than 17 inches. However, the condition is also common in women and not all sufferers are overweight. Almost everybody who has sleep apnea is a snorer, often a very heavy snorer. Pauses in breathing during sleep are commonly noticed by a bed partner but this history is often lacking and up to five "events" per hour are considered normal. One of the more consistent symptoms is "nonrestorative sleep" meaning that the patient wakes in the morning feeling unrefreshed no matter how much he slept during the night. Excessive daytime sleepiness is common in sleep apnea of any severity but some patients complain of fatigue rather than sleepiness. However, many patients with severe sleep apnea have no complaint of sleepiness or fatigue.
The most accurate diagnostic tool, polysomnography, can confirm the diagnosis and assist the doctor in identifying the type of sleep apnea present. In the past, this test was only done in hospitals and in specialized sleep laboratories. There are now portable sleep recording systems that can perform unattended polysomnography in the patient's home but in-laboratory testing with a technician present remains the number 1 standard and it is required by many insurers, (eg. Medicare of the United States) before they will pay for treatment of the condition.
With advances in portable electronics, patients can now use a small device that is attached to a fingertip to measure the oxygen saturation of the blood (percent of the total hemoglobin that is combined with oxygen), which is a procedure called pulse oximetry. This is a non-intrusive procedure based on the difference in the color of the oxygenated and of the deoxygenated hemoglobins. Recordings of blood oxygen saturation during sleep may give an estimate of the severity of the problem. However, oximetry is not a reliable screening tool.
Treatment
There are a variety of treatments for sleep apnea, depending on an individual's medical history and the severity of the disorder. Most treatment regimens begin with lifestyle changes, such as avoiding alcohol and medications that relax the central nervous system (for example, sedatives and muscle relaxants), losing weight, and quitting smoking. Some people are helped by special pillows or devices that keep them from sleeping on their backs, or oral appliances to keep the airway open during sleep. If these conservative methods are inadequate, doctors often recommend continuous positive airway pressure (CPAP), in which a face mask is attached to a tube and a machine that blows pressurized air into the mask and through the airway to keep it open. There are also surgical procedures that can be used to remove tissue and widen the airway. Some individuals may need a combination of therapies to successfully treat their sleep apnea.
The most widely used current therapeutic intervention is positive airway pressure whereby a breathing machine pumps a controlled stream of air through a mask worn over the nose, mouth, or both. The additional pressure splints or holds open the relaxed muscles, just as air in a balloon inflates it. There are several variants:
- (CPAP), or Continuous Positive Airway Pressure, in which a controlled air compressor generates an airstream at a constant pressure. This pressure is prescribed by the patient's physician, based on an overnight test or titration.
- (BiPAP), or Bilevel Positive Airway Pressure, uses an electronic circuit to monitor the patient's breathing, and provides two different pressures, a higher one during inhalation and a lower pressure during exhalation. This system is more expensive, and is sometimes used with patients who have a higher than average CPAP pressure and/or who find breathing out against an increased pressure to be uncomfortable or disruptive to their sleep.
- (APAP), or Auto-titrating Positive Airway Pressure, is the most advanced form of such treatment. An APAP machine incorporates pressure sensors and a computer which continuously monitors the patient's breathing performance. It adjusts pressure continuously, increasing it when the user is attempting to breathe but cannot, and decreasing it when the pressure is higher than necessary.
While the face mask makes some sufferers hesitant to try treatment, many patients find that the initial difficulty of adapting to the machine is quickly surpassed by improved, deeper sleep. In addition, the introduction of masks that resemble a oversized oxygen cannula have been better tolerated by some users. The vast majority of patients are surprised to find that they tolerate the mask fairly easily and sleep well while wearing it. Despite their nature as "air compressors", modern CPAP machines are extremely quiet.
These treatments are often used with accompanying humidification, as some users experience a drying effect of the airway and mucous membranes. In the United States, these machines require a prescription. A sleep study is first done to determine what kind of treatment is needed, and to determine the proper settings for the nPAP device.
A second type of physical intervention, a Mandibular advancement splint (MAS), is sometimes prescribed for mild or moderate sleep apnea sufferers. The device is a mouthguard similar to those used in sports to protect the teeth. For apnea patients, it is designed to hold the lower jaw slightly down and forward relative to the natural, relaxed position. This position holds the tongue further away from the back of the airway, and may be enough to relieve apnea or improve breathing for some patients.
Few drug-based treatments of obstructive sleep apnea are known despite over two decades of research and tests.
Oral administration of the methylxanthine theophylline (chemically similar to caffeine) can reduce the number of episodes of apnea, but can also produce side effects such as palpitations and insomnia. Theophylline is generally ineffective in adults with OSA, but is sometimes used to treat Central Sleep Apnea (see below), and infants and children with apnea.
In 2003 and 2004, some neuroactive drugs, particularly a couple of the modern-generation antidepressants including mirtazapine, have been reported to reduce incidences of obstructive sleep apnea. As of 2004, these are not yet frequently prescribed for OSA sufferers.
When other treatments do not completely treat the OSA, drugs are sometimes prescribed to treat a patient's daytime sleepiness or somnolence. These range from stimulants such as amphetamines to modern anti-narcoleptic medicines. The anti-narcoleptic modafinil is seeing increased use in this role as of 2004.
In some cases, weight loss will reduce the number and severity of apnea episodes, but for most patients overweight is an aggravating factor rather than the cause of OSA. In the morbidly obese a major loss of weight, such as occurs after bariatric surgery, can sometimes cure the condition.
Many researchers believe that OSA is at root a neurological condition, in which nerves that control the tongue and soft palate fail to sufficiently stimulate those muscles, leading to over-relaxation and airway blockage. A few experiments and trial studies have explored the use of pacemakers and similar devices, programmed to detect breathing effort and deliver gentle electrical stimulation to the muscles of the tongue.
This is not a common mode of treatment for OSA patients as of 2004, but it is an active field of research.
A number of different surgeries are often tried to improve the size or tone of the patient's airway. For decades, tracheostomy was the only effective treatment for sleep apnea. It is used today only in very rare, intractable cases that have withstood other attempts at treatment. Modern treatments try one or more of several options, tailored to the patient's needs. Often the long term success rate is low, prompting many doctors to favour CPAP as the gold standard.
- Nasal surgery, including turbinectomy (removal or reduction of a nasal turbinate), or straightening of the nasal septum, in patients with nasal obstruction or congestion which reduces airway pressure and complicates OSA.
- Tonsilectomy and/or adenoidectomy in an attempt to increase the size of the airway.
- Removal or reduction of parts of the soft palate and some or all of the uvula, such as uvulopalatopharyngoplasty (UPPP) or laser-assisted uvulopalatoplasty(LAUP). Modern variants of this procedure sometimes use radiofrequency waves to heat and remove tissue.
- Reduction of the tongue base, either with laser excision or radiofrequency ablation.
- Genioglossus Advancement, in which a small portion of the lower jaw which attaches to the tongue is moved forward, to pull the tongue away from the back of the airway.
- Hyoid Suspension, in which the hyoid bone in the neck, another attachment point for tongue muscles, is pulled forward in front of the larynx.
- Maxillomandibular advancement (MMA). A more invasive surgery usually only tried in difficult cases where other surgeries have not relieved the patient's OSA, or where an abnormal facial structure is suspected as a root cause. In MMA, the patient's upper and lower jaw are detached from the skull, moved forward, and reattached with pins and/or plates.
- Pillar procedure, three small inserts are injected into the soft palate to offer support, reducing snoring and sleep apnea.
Prognosis
Untreated, sleep apnea can be life threatening. Excessive daytime sleepiness can cause people to fall asleep at inappropriate times, such as while driving. Sleep apnea also appears to put individuals at risk for stroke and transient ischemic attacks (TIAs, also known as "mini-strokes"), and is associated with coronary heart disease, heart failure, irregular heartbeat, heart attack, and high blood pressure. Although there is no cure for sleep apnea, recent studies show that successful treatment can reduce the risk of heart and blood pressure problems.
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