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    Sleep Studies

    Sleep Studies



    Results

    Sleep studies are tests that record what happens to your body during sleep to find out what is causing your sleep problems. A polysomnogram (PSG) study checks your brain activity, eye movement, oxygen blood level, heart rate and rhythm, breathing rate and rhythm, the flow of air through your mouth and nose, the amount of snoring, body muscle movements, and chest and belly movements.

    Sleep study results are generally available within 1 to 2 weeks. A Reference sleep medicine specialist Opens New Window, Reference family medicine doctor Opens New Window, Reference internist Opens New Window, or Reference pulmonologist Opens New Window can review your results at a follow-up visit. The sleep lab technician will not be able to review the results of the study with you.

    Normal

    Polysomnogram (PSG) study
    Brain activity (Reference electroencephalogram Opens New Window, or EEG):

    Sleep time, Reference stages of sleep (NREM and REM), and awake time are normal. No abnormal brain activity (such as a Reference seizure Opens New Window) is noted.
    Eye movement (electrooculogram, or EOG):

    Slow eye movements are present at the start of sleep and change to rapid eye movements during REM sleep.
    Muscle movement (Reference electromyogram Opens New Window, or EMG):

    No leg jerking or other abnormal muscle movement is present.
    Blood oxygen (O2) level:

    Blood O2 level is greater than 90%.
    Heart rate and rhythm (Reference EKG Opens New Window, ECG):

    Heart rate and rhythm are normal. No heart rate changes (Reference arrhythmias Opens New Window), such as an abnormally slow or fast heart rate, are noted.
    Breathing effort (respiratory disturbance index, or RDI):

    Reduced air flow (hypopnea) or no air flow (apnea) to the lungs occurs fewer than 5 times in 1 hour.
    Chest and belly movements:

    The chest and belly move normally throughout the study.
    Audio and video recordings:

    Sleep is restful and not disturbed. Night terrors, sleepwalking, and sleep talking do not occur.
    Snoring monitor:

    Excessive snoring or abnormal snoring patterns are not present.
    Airflow monitors:

    Airflow through the mouth and nose is not blocked.

     

    Multiple sleep latency test (MSLT)
    Sleep onset:

    Taking 10 to 20 minutes to fall asleep is normal.

     

    Maintenance of wakefulness test (MWT)
    Sleep onset:

    Being awake for about 25 minutes is normal.

     

    Abnormal values

    • For a polysomnogram, reduced or blocked air flow to the lungs (RDI value) that occurs more than 5 times in 1 hour may mean you have Reference sleep apnea Opens New Window.
    • For a multiple sleep latency test (MSLT), taking an average of 5 to 10 minutes to fall asleep means you have mild to moderate daytime sleepiness. An average of less than 5 minutes to fall asleep means you have severe daytime sleepiness. An average of less than 8 minutes to fall sleep along with 2 or more rapid eye movements (REM) during 5 to 6 naps means you may have Reference narcolepsy Opens New Window.
    • For a maintenance of wakefulness test (MWT), falling asleep in less than 25 minutes is considered abnormal. This means you have severe daytime sleepiness. People who have Reference narcolepsy Opens New Window also may have abnormal test results.



    By: Reference Healthwise Staff Last Revised: Reference June 17, 2011
    Medical Review: Reference Anne C. Poinier, MD - Internal Medicine
    Reference Mark A. Rasmus, MD - Pulmonology, Critical Care Medicine, Sleep Medicine


    This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Reference Terms of Use. Reference How this information was developed to help you make better health decisions.


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