Department of Neurology
Department of Neurosurgery
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Polysomnography Test (PSG)
University of Iowa Department of Neurology
Peer Review Status: Internally Peer Reviewed
Creation Date: Unknown
Last Revision Date: June 2000
The PSG test is an all-night sleep study. During the study, various physical functions are monitored and the results are recorded on paper--in fact, over 1,000 sheets of paper.
What is it?
- an all-night sleep study
- monitors various physical functions during sleep
- electrical activity of your heart
- brian wave patterns
- eye movement
- muscle tone
- body movements
How long does it take?
Why is a PSG performed?
- helps evaluate the cause of excessive daytime sleepiness, insominia, or unusual spells occurring during sleep
- if other sleep orders are diagnosed
- sleep apnea (disturbances of breathing during sleep)
- narcolepsy (sudden and uncontrollable onsets of sleep)
Does it hurt?
- no. you will experience no pain or discomfort
Where is it conducted
- Neurology Sleep Disorder Center 2nd floor Carver Pavilion
How many PSGs are conducted each year?
What should you do to prepare for the test?
- come in for the test about two hours before normal bedtime to allow for preparation
- bring all medications you are currently taking with you when you come for the test. You may continue taking all medications unless your doctor gives other instructions
- bring suitable nightware such as pajamas and a bathrobe
- eat supper as usual the night of the test
- wash your hair before coming for the test. Do not apply sprays, oils, or dressings of any kind
How is it performed?
- a technologist measures your head so that all attachments fit comfortably
- soft, red pencil marks are made on your scalp where electrodes will be placed
- several electrodes are places on your chest and legs
- electrodes are glued to your scalp and skin with an air blower
- special jelly is applied to each electrode. Nothing goes into or under your skin.
- each electrode connection is checked with a meter to insure that it is working properly
- an elastic belt is placed around your chest to measure your breathing
- heat-sensitive wires are placed by your nose and mouth to monitor air flow during breathing
- a probe is taped to your finger to measure the oxygen saturation of your blood
During the test
- you will be in a room by yourself and asked to sleep on a bed
- a technologist monitors the recordings in another room
- an intercom is available so that you may call the technologist at any time
- don't worry if you cannot sleep during the test. The information gained will still be useful.
Following the test
- after the testing period, the technologist will awaken you and disconnect all wires
- the electrodes are removed with acetone, which dissolves the glue and leaves your hair and skin intact
- you may wash your hair when you return to your hospital room or home, unless your doctor gives you other instructions
- you will learn the test results from the doctor either on the day of your visit, or the results of your study will be sent to your referring doctor.