What are the Sleep Studies (polysomnogram)

Sleep Studies (polysomnogram) are a series of tests done while you are sleeping. A sleep study records your brain waves, heart rate, breathing rate, oxygen level, and eye and leg movements.

A sleep study helps your health care provider:

• See how well you sleep.
• Diagnose a sleep disorder.
• Determine how severe your sleep disorder is.
• Create a plan to treat your sleep disorder.

Your health care provider may recommend a sleep study if you:

• Feel sleepy on most days.
• Snore loudly while sleeping.
• Have unusual behaviors while you sleep, such as walking.
• Have brief periods in which you stop breathing during sleep (sleepapnea).
• Fall asleep suddenly during the day (narcolepsy).
• Have trouble falling asleep or staying asleep (insomnia).
• Feel like you need to move your legs when trying to fall asleep (restless legs syndrome).
• Move your legs by flexing and extending them regularly while asleep (periodic limb movement disorder).
• Act out your dreams while you sleep (sleep behavior disorder).
• Feel like you cannot move when you first wake up (sleep paralysis).

What tests are part of a sleep study?

Most sleep studies record the following during sleep:

• Brain activity.
• Eye movements.
• Heart rate and rhythm.
• Breathing rate and rhythm.
• Blood-oxygen level.
• Blood pressure.
• Chest and belly movement as you breathe.
• Arm and leg movements.
• Snoring or other noises.
• Body position.

Where are sleep studies done?

Sleep studies are done at sleep centers. A sleep center may be inside a hospital, office, or clinic.

The room where you have the study may look like a hospital room or a hotel room. The health care providers doing the study may come in and out of the room during the study. Most of the time, they will be in another room monitoring your test as you sleep.

How are sleep studies done?

Most sleep studies are done during a normal period of time for a full night of sleep. You will arrive at the study center in the evening and go home in the morning.

Before the test

• Bring your pajamas and toothbrush with you to the sleep study.
• Do not have caffeine on the day of your sleep study.
• Do not drink alcohol on the day of your sleep study.
• Your health care provider will let you know if you should stop taking any of your regular medicines before the test.

During the test

• Round, sticky patches with sensors attached to recording wires (electrodes) are placed on your scalp, face, chest, and limbs.
• Wires from all the electrodes and sensors run from your bed to a computer. The wires can be taken off and put back on if you need to get out of bed to go to the bathroom.
• A sensor is placed over your nose to measure airflow.
• A finger clip is put on your finger or ear to measure your blood oxygen level (pulse oximetry).
• A belt is placed around your belly and a belt is placed around your chest to measure breathing movements.
• If you have signs of the sleep disorder called sleep apnea during your test, you may get a treatment mask to wear for the second half of the night.
  • The mask provides positive airway pressure (PAP) to help you breathe better during sleep. This may greatly improve your sleep apnea.
  • You will then have all tests done again with the mask in place to see if your measurements and recordings change.

After the test

• A medical doctor who specializes in sleep will evaluate the results of your sleep study and share them with you and your primary health care provider.
• Based on your results, your medical history, and a physical exam, you may be diagnosed with a sleep disorder, such as:
  • Sleep apnea.
  • Restless legs syndrome.
  • Sleep-related behavior disorder.
  • Sleep-related movement disorders.
  • Sleep-related seizure disorders.
• Your health care team will help determine your treatment options based on your diagnosis. This may include:
  • Improving your sleep habits (sleep hygiene).
  • Wearing a continuous positive airway pressure (CPAP) or bi-level positive airway pressure (BPAP) mask.
  • Wearing an oral device at night to improve breathing and reduce snoring.
  • Taking medicines.

Follow these instructions at home:

• Take over-the-counter and prescription medicines only as told by your health care provider.
• If you are instructed to use a CPAP or BPAP mask, make sure you use it nightly as directed.
• Make any lifestyle changes that your health care provider recommends.
• If you were given a device to open your airway while you sleep, use it only as told by your health care provider.
• Do not use any tobacco products, such as cigarettes, chewing tobacco, and e-cigarettes. If you need help quitting, ask your health care provider.
• Keep all follow-up visits as told by your health care provider. This is important.

Summary

• A sleep study (polysomnogram) is a series of tests done while you are sleeping. It shows how well you sleep.
• Most sleep studies are done over one full night of sleep. You will arrive at the study center in the evening and go home in the morning.
• If you have signs of the sleep disorder called sleep apnea during your test, you may get a treatment mask to wear for the second half of the night.
• A medical doctor who specializes in sleep will evaluate the results of your sleep study and share them with your primary health care provider.