Polysomnogram | Polysomnogram Test | Diagnosis Of Sleep Disorders


A polysomnogram records your breathing patterns and the electrical activity in your brain while you are sleeping.

This test is used to evaluate various sleep disorders.

It's totally safe and painless -- although a bit peculiar, going to sleep in a strange room with dozens of wires and devices stuck to your body. 

Stages Of Sleep

There are two states of sleep: non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep. REM sleep is associated with dreaming and paralysis of body muscles (except for the eye and diaphragm muscles).

NREM sleep has four stages distinguishable by EEG waves. REM sleep alternates with NREM sleep approximately every 90 minutes. A person with normal sleep usually has four to five cycles of REM and NREM sleep during a night.


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.

Polysomnogram Test:

Polysomnogram is generally 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 chin, the scalp, and the outer edge of the eyelids 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.

The polysomnogram is painless and takes approximately 12 hours to complete. You may resume your normal activities immediately.

Most people sleep very well. The sensors are applied to the surface of your skin in a trouble-free way that allows you to move and turn during your sleep. Generally, you will not be conscious that you are wearing them after they have been on for a short time. Remember, this is not a ‘test’, merely a recording of how you sleep.

A polysomnogram is a test that measure bodily functions during sleep.

Typical Measurements Of Polysomnogram Test Include:

  • Muscle tension (sensors on the chin)
  • Heart beat (sensors placed on chest)
  • Leg movements (sensors placed on calf)
  • Airflow (sensor above the upper lip)
  • Breathing effort (expandable belt placed around the waist)
  • Oxygen level (small sensor on finger)
  • Brain waves (sensors placed on scalp)
  • Eye movements (sensors placed above and below the eye(s))

The test is performed to evaluate possible sleep disorders, such as excessive daytime sleepiness, obstructive sleep apnea, narcolepsy, insomnia, hypersomnia, breathing difficulties during sleep, behavior disturbances during sleep, or other sleep disorders.


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