The diagnosis of sleep apnea is relatively straightforward, based on sleep history and an overnight sleep study called a polysomnogram. Polysomnography is performed in a sleep laboratory under the direct supervision of a trained technologist. During the test, a variety of body functions, such as the electrical activity of the brain, eye movements, muscle activity, heart rate, breathing patterns, air flow, and blood oxygen levels are recorded at night during sleep. After the study is completed, the number of times breathing is impaired during sleep is tallied and the severity of sleep apnea is graded. In some cases, a multiple sleep latency test is performed on the day after the overnight test to measure the speed of falling asleep. In this test, patients are given several opportunities to fall asleep during the course of a day when they normally would be awake. If you have symptoms of sleep apnea, your doctor may ask you to have a sleep evaluation in a sleep disorder center.

Learn more about the diagnosis of sleep apnea.

The diagnosis of sleep apnea starts with an examination by your doctor, who will take a history and perform a physical examination. Of course that means you have to go to your doctor and tell him your symptoms. He may ask you to fill out a questionnaire about your sleep and breathing that will identify risk factors for sleep apnea. This is all stuff that takes place while you are awake, so if sleep apnea is suspected, then obviously you must be examined while you are asleep. That examination can take place in your home unless a sleep disorder other than sleep apnea is suspected, or there are reasons that a technician must be with you during the test. If that is the case then the examination will probably be done in a sleep laboratory. The laboratory study typically involves having a variety of sensors placed on you by a technician, so that brain waves, eye movements and muscle activity can be recorded. This allows the determination of sleep and sleep stages by the classic methodology. Both home testing and laboratory testing usually involve the recording of snoring, body or head position, movement, airflow at the airway opening, effort to breathe, pulse or heart rate and blood oxygen levels by an oximeter (a non-invasive device that is worn on the finger, ear or forehead). Some home testing devices also can record brain waves for an estimation of sleep time.

The information stored on the home or laboratory recorder can be reviewed by a specialist in sleep medicine, and a determination made if you have sleep apnea or not, the kind of sleep apnea you have (there are two major types, obstructive and central and they can occur together), and how severe the problem is in terms of the frequency of abnormal breathing events overall and by sleeping position. The amount of time you spend with low oxygen levels will also be determined. A report of those findings is then sent to your doctor who ordered the study. The diagnostic sleep study is perfectly safe, and when done in your own bed, reasonably comfortable.