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Sleep Studies
Overview
If you're having difficulty getting enough restful sleep, your doctor may recommend a sleep study. Sleep studies measure how well and how long you sleep and can detect if you have a sleep disorder.
Most sleep studies are done at home. Your care team will provide a device and show you how to use it. Treating a sleep disorder can help improve your energy and alertness during the day, improve your memory, and prevent accidents or injuries that can occur when people are tired.
Why It's Done
Sleep disorders increase the risk of developing several serious health conditions. These include stroke, heart attack, high blood pressure, diabetes, and depression. Chronic tiredness can also make traffic accidents and injuries from falls more likely. Sleep problems also negatively affect your quality of life, relationships, and ability to be productive at work or school. Identifying and treating sleep disorders can help prevent these illnesses and problems.
Although your doctor may be able to diagnose some sleep disorders by talking with you (or your sleeping partner), sleep studies provide a lot more information about your body during sleep. Sleep study devices can monitor how you breathe, snore, or move while asleep. Sleep studies can help to diagnose the underlying causes of:
- Heavy, excessive snoring
- Insomnia
- Twitching or jerking limbs in the night
- Chronic, irresistible sleepiness during the day
- Difficulty falling asleep at night
- Waking in the night and having trouble falling back asleep
- Muscle weakness during the day
Types
There are different types of sleep studies. Your doctor may refer you for sleep testing that you do at home or in a sleep clinic.
At-home sleep study
This simple test can be done in the comfort of your own bed at home. It’s typically used to diagnose obstructive sleep apnea. Home sleep study devices measure your breathing, blood oxygen level, and heart rate. The results can help your doctor understand how effective treatments such as continuous positive airway pressure (CPAP) therapy, oral appliances, or surgery are likely to be.
Actigraphy
This at-home test involves wearing a wristwatch-like device called an actigraph as you go about your daily activities. It's usually worn for several days and nights and records when and how often you sleep. Actigraphy can help diagnose various sleep disorders, particularly those caused by jet lag, shift work, or other schedule changes to your body's natural internal clock (circadian rhythm). It can also help to evaluate how well treatment for a sleep disorder is working.
Polysomnogram (PSG)
PSG testing is typically conducted in our sleep lab. You’ll spend the night there, and the sleep lab care team will monitor you throughout the night. The PSG records several body functions during sleep, including heart and breathing rate, brain activity, blood oxygen levels, and eye movements. This test can help diagnose sleep-related breathing disorders, such as parasomnia, narcolepsy, and others.
Multiple sleep latency test (MSLT)
This in-lab test measures how sleepy a person is during the day and how long it takes them to fall asleep for a nap in a quiet room. The MSLT records brain activity and the stages and types of sleep someone experiences. This test can help to diagnose disorders such as narcolepsy and idiopathic hypersomnia, a condition characterized by excessive sleeping.
Maintenance of wakefulness test (MWT)
An MWT test in our sleep lab helps determine your ability to remain awake during the day and can also help check the effectiveness of different kinds of sleep therapy.
How to Prepare
Preparation will depend on the type of sleep study you do. Your care team will provide you with the device and instructions for an at-home sleep study. Instructions vary for each type of device. They may ask you to:
- Complete a questionnaire about your sleep patterns before and after testing.
- Avoid using alcohol, caffeine, and other stimulants during the afternoon and evening before your test.
- Remove any nail polish or artificial nails from the ring finger of your dominant hand.
- Return the device to the medical center the following day.
For other sleep studies done in the sleep lab, your care team will give you specific preparation instructions.
How It's Done
Each type of sleep study has a slightly different method of testing and diagnosis. At-home sleep study instructions will vary based on the type of device used. For example, some use a watch-style device with a finger probe, while others may use a small strap around your finger. These tests are noninvasive. You use them at home where you are the most relaxed and able to sleep. Follow the instructions from your care team about how to operate the device and return it at the end of the test.
Results
The results of a sleep study will generally be available within about 1 to 2 weeks, depending on the type of test you had. Your doctor will evaluate the results together with your medical history to reach a diagnosis. They’ll reach out to you with treatment options and other steps you can take to improve your sleep.
The results can help reveal sleep-related breathing disorders such as sleep apnea or other disorders. They can also help your doctor evaluate the effectiveness of a CPAP machine and other treatments.