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Sleep Studies: About This Test

What is it?

Sleep studies are tests that watch what happens to your body during sleep. These studies usually are done in a sleep lab. Sleep labs are often located in hospitals. But sleep studies also can be done with portable equipment that you use at home.

Why is this test done?

Sleep studies are done to find sleep problems, including:

  • Sleep apnea or excessive snoring.
  • Narcolepsy.
  • Nocturnal seizures.
  • REM behaviour disorder (RBD).
  • Repeated muscle twitching of the feet, arms, or legs while you sleep.

How can you prepare for the test?

  • You may be asked to keep a sleep diary for 1 to 2 weeks before your sleep study.
  • Don't take any naps for 2 to 3 days before your test.
  • You may be asked to avoid food or drinks with caffeine for a day or two before your test.
  • Take a shower or bath before your test, but don't use sprays, oils, or gels on your hair. Don't wear makeup, fingernail polish, or fake nails.
  • Pack and take along a small overnight bag with personal items, such as a toothbrush, a comb, favourite pillows or blankets, and a book. You can wear your own nightclothes.

What happens during the test?

  • In the sleep lab, you will be in a private room, much like a hotel room.
  • Small pads or patches called electrodes will be placed on your head and body with a small amount of glue and tape. These will record things like brain activity, eye movement, oxygen levels, and snoring.
  • Soft elastic belts will be placed around your chest and belly to measure your breathing.
  • Your blood oxygen levels will be checked by a small clip (oximeter) placed either on the tip of your index finger or on your earlobe.
  • If you have sleep apnea, you may wear a mask that is connected to a continuous positive airway pressure (CPAP) machine.
  • Depending on the type of test, you will be allowed to sleep through the night or you will be awakened periodically and asked to stay awake for a while.

What else should you know about the test?

  • It may feel odd to be hooked to the sleep study equipment. The sleep lab technician understands that your sleep may not be the same as it is at home because of the equipment. Try to relax and make yourself as comfortable as possible.
  • After your sleep problem has been identified, you may need a second study if your doctor orders treatment such as CPAP.
  • Portable sleep study equipment is available for a person to do sleep studies at home. This may be a choice for people who have problems sleeping in a sleep lab. But home sleep studies may not give the same results as a sleep lab.

How long does the test take?

  • You will stay in the sleep lab overnight. For some tests, you will also stay part of the next day.

What happens after the test?

  • You will be able to go home right away.
  • You can go back to your usual activities right away.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse call line if you are having problems. It's also a good idea to keep a list of the medicines you take. Ask your doctor when you can expect to have your test results.

Where can you learn more?

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