Diagnosis of Sleep Disorders
Medical History & Sleep Disorder Diagnosis
As with other neurological disorders, an accurate medical history is an essential part of diagnosing a sleep disorder. People with sleep disorders should keep a daily diary of activities and sleepboth when they try to go to sleep and when they actually do fall sleep. Behavior during sleep (e.g., snoring), as well as the use of alcohol, tobacco, and other drugs, should be reported to the physician.
Polysomnography & Sleep Disorder Diagnosis
A polysomnogram is a sleep study that involves using electroencephalography (EEG) to monitor the brain and muscle activity, heart rhythm, and breathing during sleep. Patients are usually tested in a sleep center (sleep lab, sleep clinic) or are given portable equipment to take home. The EEG monitors the various stages of sleep, which is then interpreted by the clinician. For example, the EEG shows the degree of muscle activity during the various NREM and REM sleep stages. This information may provide clues about the type and cause of the sleep disorder.
Other Tests to Diagnose Sleep Disorders
In people with suspected obstructive sleep apnea (OSA), overnight oximetry (measuring the oxygen saturation in the blood) may be performed to determine the oxygen level during the apnea episodes.
In people with suspected narcolepsy, there are various tests that can be performed. The multiple sleep latency test (MSLT), for example, measures the time it takes for REM sleep to occur in patients who fall asleep suddenly and repeatedly. In people with narcolepsy, REM occurs immediately.