Diagnosis of OSA should be made by a primary care physician, pulmonologist, neurologist or other physician with specialty training in sleep disorders. Diagnosis is not simple because there can be many different reasons for disturbed sleep. In addition to a complete medical history and physical examination, diagnostic procedures for obstructive sleep apnea may include a sleep history and evaluation of the upper airway.

Polysomnography is the most common test used to determine if obstructive sleep apnea is present. Sometimes, simpler portable diagnostic procedures could be used to diagnose OSA. However, if the test doesn’t confirm OSA in a symptomatic patient, a full polysomnography test will need to be performed. A Polysomnography patient sleeps in a laboratory overnight. Electrodes are attached to the scalp, on the outer edge of the eyelids and to the skin on the chin. Belts are placed around the chest and abdomen. A cannula is placed in the nose to measure airflow and a probe is placed on the finger to measure the blood oxygen level. While the patient sleeps, the polysomnography records body functions such as eye movement, muscle activity, heart rate, respiration, blood oxygen levels, airflow and the electrical activity of the brain. This information is then gathered and evaluated.

The Multiple Sleep Latency Test (MSLT) measures the speed of falling asleep. In this test, patients are given several opportunities to fall asleep during the course of a day when they would normally be awake. For each opportunity, time to fall asleep is measured. Individuals who fall asleep in less than 5 minutes are likely to require some type of treatment for sleep disorders. The MSLT may be useful to measure the degree of excessive daytime sleepiness and to rule out other types of sleep disorders.