Sleep Apnea

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Since people with sleep apnea may complain of any number of sleep-related symptoms, including excessive daytime sleepiness, your doctor can order a range of tests to look for possible causes of those symptoms.

Your doctor may order lab tests, including those to test for medicines that are known to affect the level of alertness.

Your doctor may do a physical exam of your nose, mouth, and throat, looking for large or extra tissues that might be blocking the flow of air. Your doctor may also ask you how well you sleep and how well you function during the day.

Your doctor may want you to have an overnight sleep study, in which you spend the night in a sleep lab while instruments record data on your sleep and other bodily functions.

This section contains more information on:

  • Sleep study
  • Sleep study preparation
  • Other sleep tests
  • Sleep study

    Your doctor may suspect that you have sleep apnea based on your symptoms, but an overnight sleep study is required to confirm the diagnosis. A sleep study, also called a polysomnogram, is a painless, noninvasive test that records your physical state during various stages of sleep. It provides data that are essential in evaluating sleep and sleep-related complaints and problems, such as identifying sleep stages, body position, blood oxygen levels, respiratory events, muscle tone, heart rate, eye movement, brain waves, amount of snoring, and general sleep behavior. If you have sleep apnea, the study will record repeated awakenings, pauses in breathing, and drops in oxygen level in the blood.

    Sleep studies are performed in a sleep lab that is specially equipped with computerized monitoring equipment. Most sleep studies take place at night. After you change into your nightclothes, the technician will connect you to a number of electrodes that will record your brain waves and muscle movements throughout the night. A microphone will record snoring, and two belt-like straps around the chest and lower abdomen will monitor muscle movement during breathing. Despite all of the equipment, most people say their sleep is not disrupted. After the technician is certain that electrodes are recording properly, the lights will be turned off and you can go to sleep. You will be able to talk to the technician, who will constantly monitor your test from an adjoining room. The technician will also help you if you need to use the restroom during the night.

    In a sleep study for sleep apnea, you may undergo a "split-night" test, in which half the night will be used to diagnose your sleep problem, and the other half will be used to determine the best way to treat the problem. Or, you may be asked to return for another sleep study in order to determine the best way to treat your sleep apnea. In that second study (or second half of the night), you will be treated with continuous positive airway pressure , which blows air lightly into the nose and/or mouth to increase air pressure enough to hold the airway open and allow you to breathe. The study is done at different air pressures to determine what level works best for you.

    You will be awakened in the morning, the electrodes will be removed, and you may shower and dress. Since the electrodes are applied with water-soluble glue or tape, removal is not painful. You will be asked to complete a questionnaire concerning your sleep the previous night, and then you can go home.

    Your physician will explain the results to you and talk with you about follow-up treatment, if required.

    In some cases, the sleep study can be done at home. For some sleep centers, a technician will come to your home to help you attach the monitor that will record data about your sleep. The technician will return in the morning to take the monitor away.

    Sleep study preparation

    Items to bring to your sleep study:

    • Your ID and insurance information
    • Pajamas or any comfortable sleep wear, preferably with a button-down front. A nightgown is impractical for attaching electrodes and straps to the chest and lower abdomen.
    • Your favorite pillow and blankets. The sleep lab will provide pillows and blankets, but yours may help you sleep better.
    • Toiletries such as toothbrush, toothpaste, hairbrush or comb
    • Clothes for the following day
    • Any needed medications
    • A book or other reading material
    • A snack, if desired
    • Things to do the day of your test:

      • Wash and dry your hair on the day of your Sleep Study. Do not use any hair products, such as gels, hairsprays or heavy conditioners, because these may prevent the electrodes from sticking to your scalp.
      • Ask your doctor or call the sleep lab to ask if you need to remove nail polish and/or artificial nails. The oximeter that is placed on your finger to monitor blood oxygen levels reads this information through the nail.
      • Generally, you will be asked to continue to take your regular medications. You will be notified in advance if you should alter your medications on the day of the test.
      • Do not drink any caffeinated beverages after noon on the day of your study.
      • Do not take a nap on the day of your study.
      • Other sleep tests

        Other tests to diagnose sleep disorders may include:

        Multiple sleep latency test (MSLT)


        This test, performed in a sleep lab, objectively determines your degree of sleepiness. On the day following an overnight sleep study, you will be asked to take four or five naps over an eight to ten hour period. Each nap period lasts about twenty minutes. During these nap periods, you will be closely monitored, as you were during your sleep study. Bring a book, crossword puzzles, or anything else with which you can entertain yourself between naps. Maintenance of wakefulness test (MWT)


        This test measures your ability to stay awake. It consists of four nap opportunities, each lasting 40 minutes. During the nap period, you will be asked to try to stay awake. Most people without excessive sleepiness remain awake during these nap periods. Last reviewed on 09/20/2006

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