Polysomnogram - Sleep Study

Overview & Description

A sleep study, or polysomnogram, continuously measures and records brain and body activities during sleep.

Who is a candidate for the procedure?

A sleep study may be performed if a person has:

insomnia or other sleep disorders

narcolepsy, which is excessive daytime sleepiness

sleep apnea. This condition causes low oxygen levels and frequent wake-ups due to blockage of the upper air passages.

trouble breathing during sleep

behavior disturbances during sleep, such as sleepwalking

lasting nightmares

rapid eye movement disorders

restless leg syndrome, with abnormal leg movements during the night

How is the procedure performed?

The procedure takes place in a sleep study lab over the course of the night. It is important to try to duplicate normal sleep patterns. Heavy exercise should not be done on the day of the study. A person should also avoid:

sleeping pills

alcohol

stimulant medications, such as diet pills

Usually, the person arrives at the lab around 9 p.m. for the study. A technologist will attach electrodes to the skin and scalp. This may take an hour. The electrodes do not pierce the skin, but are held in place by removable gel and tape.

When the person is ready to go to bed, the electrodes are linked to recording equipment. The technologist sits in a central control area, which is separate from the bedrooms. During the observation period, the person is attached to the following:

electocardiogram (ECG), which monitors the heart

pulse oximetry, which monitors the blood oxygen level

electoencephalogram (EEG), which monitors the brain activity

electromyography (EMG), which monitors skeletal muscle activity

Preparation & Expectations

What happens right after the procedure?

The electrodes are removed in the morning, and the person can then go home.

Home Care and Complications

What happens later at home?

The person should make an appointment to discuss the test results with his or her healthcare provider. It may take a few weeks to get the results.

What are the potential complications after the procedure?

It may be hard to sleep well during the study, and a person will often feel tired afterward.