5 Types of Sleep Studies

Medically Reviewed on 7/7/2022
5 Types of Sleep Studies
Sleep difficulties can have a negative impact on your health, safety, and general quality of life.

A sleep study, also known as polysomnography, is a noninvasive overnight evaluation that allows doctors to monitor your brain and body while you sleep.

  • During the study, a machine called a polysomnogram captures your eye and leg movements, as well as your heart rate, blood oxygen level, and breathing.
  • The test is used to diagnose sleep disorders. Sleep disorders are conditions, such as difficulty falling asleep, sleeping excessively, and breathing irregularly during sleeping, that causes problems with sleeping.
  • Sleep difficulties can hurt your health, safety, and general quality of life.
  • Sleep deprivation can put you at risk for major illnesses such as depression, diabetes, and heart disease. It could also result in automobile accidents and other types of accidents.
  • Getting a sleep disorder diagnosed and treated early can help you avoid health complications. If you've previously been diagnosed with a sleep disturbance, polysomnography can help you start or change your treatment strategy.

Why do I need a sleep study?

You may need this test if you have symptoms of a sleep disorder, such as:

  • Loud snoring during sleep
  • Waking up from sleep and gasping for breath
  • Trouble falling and/or staying asleep
  • Daytime sleepiness

5 Types of sleep studies

  1. Polysomnogram (PSG): A PSG is a diagnostic tool used to determine if your patient has a sleep disorder. At the sleep clinic or hospital, this test is carried out overnight.
    • It monitors patients' sleep cycles and stages to identify any disturbances caused by their sleep disorder.
    • The patient will be connected to a variety of equipment to help monitor things such as their brain activity, breathing activity, and muscle activity.
    • Through a PSG, the doctor documents the disorder patient is suffering from.
    • Patients with sleep disorders, such as obstructive sleep apnea (OSA), are the best candidates for a PSG. The disease is characterized by the patient's repeated apnea episodes or obstruction of the upper airway that limits or prevents airflow while they are sleeping.
    • A polysomnogram is used to identify a variety of sleep disorders, including central sleep apnea, OSA, other problems of breathing while asleep, disorders of rapid eye movement (REM), and other parasomnias (abnormal actions or behaviors while sleeping).
  2. Continuous positive airway pressure (CPAP) titration: This study is performed after a diagnosis of sleep apnea has been made. CPAP titration studies are conducted overnight in the sleep laboratory.
    • During the study, you will monitor the patient's breathing and adjust the CPAP pressure to determine the proper air pressure required to prevent upper airway blockage, eliminating pauses in their breathing while the patient sleeps.
    • The patient is fitted with a nasal mask that connects to a tube on a small pressure-generating device.
    • During a CPAP titration, a patient’s sleep is monitored just like you would during an in-lab diagnostic sleep study. You'll measure their breathing, heart rate, oxygen levels, brain waves, and arm and leg movements.
    • If necessary, throughout the night, the CPAP pressure for the patient will be adjusted remotely. Low pressures are first applied to the patient, and as events are observed, the pressure is gradually raised.
    • If a patient's prior symptoms, such as snoring, apnea, or daytime sleepiness, recur despite receiving CPAP therapy, they might require a re-titration study of the device.
    • Patients with a diagnosis of a sleep breathing condition, such as OSA, are suitable candidates for CPAP titration before they begin treatment.
    • A board-certified sleep physician evaluates the information you gathered during the CPAP titration to determine the CPAP therapy setting that is most effective for the patient over time.
  3. Multiple sleep latency tests (MSLT): MSLT is used to screen for excessive daytime sleepiness and measure how quickly the patient falls asleep in a peaceful setting.
    • This test is used to identify idiopathic hypersomnia and narcolepsy (characterized by excessive daytime sleepiness and sudden attacks of sleep).
    • MSLTs are tests that last all day and include five scheduled naps that are spaced two hours apart. During each nap, the patient will quietly lie in bed while trying to fall asleep.
    • The duration of time your patient takes to fall asleep after the lights go out is measured by the test.
    • After 15 minutes of sleep, you should wake up your patient. The nap trial should be terminated if the patient doesn't fall asleep within 20 minutes.
    • You should plan for your patient to take their first nap about two hours after you wake them from the overnight sleep study. Before they try their first nap, have them eat a light breakfast.
    • To track when your patient is sleeping or awake and to determine when they are experiencing REM sleep, sensors will be positioned on their face, head, and chin.
    • People with excessive daytime drowsiness who experience sleepiness during waking hours or in circumstances when others are generally more aware and awake, such as while driving or at work, make good candidates for an MSLT.
  4. Split night study: For patients with severe OSA, a split night study is an alternative.
    • This study shortens the time to treatment by diagnosing OSA and titrating CPAP in a single night.
    • You will complete polysomnography during the first half of the night, and then CPAP titration will be performed in its place for the remaining hours.
    • Without requiring your patient to return the next night for a second test, the split night study can identify their PAP settings on the same night.
    • Patients with severe sleep apnea may be good candidates for a split-night study.
    • Split night studies are typically carried out to identify OSA. Patients who are unable to finish more than one overnight in-lab test can benefit from them.
  5. Maintenance of wakefulness test (MWT): The MWT is similar to the multiple sleep latency test (MSLT).
    • A patient is asked to sit in bed rather than lie down and to remain awake during the test.
    • This test has five sessions. The length of each session lasts about 40 minutes. Starting at about 10:00 a.m., patients have a session once every two hours.
    • The final test should take place at around 6:00 p.m., and at around 7:00 p.m., the patient will be allowed to go.
    • The capacity to fly or drive safely is assessed using this test frequently in the transportation sector.


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Medically Reviewed on 7/7/2022
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