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Alternative names Return to top
Sleep studies; Polysomnography; Rapid eye movement studiesDefinition Return to top
A polysomnograph is a test of sleep cycles and stages through the use of continuous recordings of brain waves (EEG), electrical activity of muscles, eye movement (electrooculogram), breathing rate, blood pressure, blood oxygen saturation, and heart rhythm and direct observation of the person during sleep.How the test is performed Return to top
Polysomnograms are usually conducted in a sleep study center. You will lie on a bed in the test center. The test may be carried out during the night so that normal sleep patterns can be reproduced. Electrodes are placed on the scalp, the outer edge of the eyelids, and to the skin on the chin in preparation for the test.
Characteristic patterns from the electrodes are recorded while you are awake with your eyes closed and during sleep. The time taken to fall asleep is measured as well as the time to enter REM sleep. Sometimes the movements of a person during sleep are recorded by video camera.
How to prepare for the test Return to top
Do not take any sleeping medication and do not drink alcohol or caffeine-containing beverages before the test.How the test will feel Return to top
Electrodes will be placed on the skin and scalp. Monitors to record heart rate and breathing rate will be attached to the chest. Sometimes other test to determine breathing disorders during sleep are also performed.Why the test is performed Return to top
The test is performed to evaluate possible sleep disorders, such as insomnia, hypersomnia, excessive daytime sleepiness, obstructive sleep apnea, narcolepsy, breathing difficulties during sleep, behavior disturbances during sleep, or other sleep disorders.Normal Values Return to top
Usual or normal patterns of brain waves and muscle movements during sleep.What abnormal results mean Return to top
Abnormal results may confirm a suspected sleep disorder.What the risks are Return to top
The risks are negligible as long as the tests and equipment are appropriately supervised.Special considerations Return to top
Sleep studies may be applied to other disorders. Update Date: 10/23/2003 Updated by: Elaine T. Kiriakopoulos, M.D., M.Sc., Department of Neurology, Beth Israel Deaconess Medical Center, Harvard University, Boston, MA. Review provided by VeriMed Healthcare Network.
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Page last updated: 28 October 2004 |