Most people with this sleep disorder have obstructive apnea, where the person stops breathing for a moment during sleep due to blockage in his or her throat. The sufferers usually resume breathing within a few seconds, but periods of as long as sixty seconds are not uncommon in serious cases. The basic cause is the relaxation of the muscles in the back of the throat, which close off the airway. As the body senses the lack of oxygen, the sleeper automatically wakes up, and the throat muscles are activated to open the airway, allowing breathing to resume but thereby interrupting sleep.
Obstructive sleep apnea occurs most commonly in men, and is generally exacerbated if they are overweight or obese.
Another, rather rare form is central nervous sleep apnea, where a problem in the nervous system interrupts breathing.
Such apnea can occur repeatedly during sleep. Frequent apnea reduces the oxygen supply to the brain. It also produces the results of sleep deprivation, including drowsiness, fatigue, memory loss, and short attention span, during waking hours, and even the problem of falling asleep unexpectedly at any moment, similar to narcolepsy. Serious apnea may cause brain damage, heart trouble or death.
In the past, the only way to diagnose the condition was to send the patient to a hospital to be observed with a camera and other equipment while he or she slept. With advances in portable electronics, patients are now sent home with a small electronic device that is strapped to a fingertip to measure the oxygen content of the blood. The procedure is called oximetry. It is non-intrusive because only the color of the finger need to be monitored. If the device records obvious drops in oxygen supply in the patient's blood during the course of the sleep, it gives good indications of how serious the problem is.
The primary form of treatment for obstructive apnea is the use of a breathing machine which pumps a controlled stream of air through a face mask, forcing air to open the relaxed muscles. This allows uninterrupted sleep to take place. The most common is the continuous positive airway pressure ("CPAP") machine, which delivers a low level constant air pressure to the nose and sometimes the mouth. Other variations can deliver varied levels of pressure by monitoring breathing patterns. While the thought of using a face mask can make some sufferers hesitant to try the treatment, many if not most find that the initial difficulty of acclimatizing to the machine is quickly surpassed by the return of the benefits of deep sleep.
Surgery is sometimes used to treat less severe cases; this surgery involves removal of portions of the soft palate, the back of the tongue, or both. Recently a new treatment is developed in which a probe is inserted into the nasal cavity to irradiate the soft tissues with radio wave. The airway is expected to open up after the swelling subsides. The procedure is too new to show any long term side effect though it is believed that the radio wave is harmless to the patient.