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Sleep Apnea Test: What You Can Expect

By Lan Pham, Manjari Bansal
There are several diagnostic tests available to evaluate you for the presence of sleep apnea or help guide treatment. Learn about different types of sleep tests and what to expect during each of them.

A number of tests can confirm the presence of suspected sleep apnea or give doctors valuable information used in treatment. Some sleep tests can diagnose sleep apnea, such as polysomnography (PSG) and home sleep apnea tests (HSATs). Other tests like CPAP titration, split-night studies, and maintenance of wakefulness tests (MWTs) can play an important role in the treatment of diagnosed sleep apnea.

What You Can Expect

Nearly 24 million Americans have sleep apnea, and many don't even know it, reports the American Sleep Association. The first step towards treating the disorder is getting diagnosed. The following tests can help in the diagnosis or treatment of sleep apnea. 

Polysomnography test (PSG)

This test, also called a sleep study, is recommended by physicians if they suspect you have a sleep disorder like sleep apnea, according to Mayo Clinic. It is usually conducted at a sleep center or hospital. A PSG records your brain waves, heart rate, breathing, blood oxygen level, and eye and leg movements during sleep. It's conducted by a sleep technologist who monitors all the parameters throughout the night.

At-Home Sleep Apnea Test

As the name suggests, you can do this test at home to confirm a diagnosis of obstructive sleep apnea (OSA), according to the American Sleep Association. Although it's not exactly the same as an in-lab sleep test, its benefits include convenience of use and test results gleaned from your normal, daily sleep environment.

During the test, you'll connect different parts of a portable sleep test device to your body before bedtime. The parts typically consist of a belt, a small nose tube, and a finger clip. Data about your breathing and oxygen levels during sleep is collected for 1-3 nights by the device, which your doctor later interprets.

CPAP Titration Study

A common treatment method for sleep apnea is continuous positive airway pressure (CPAP) therapy. A CPAP device delivers a steady stream of oxygen through a mask in order to prevent apneic episodes. A CPAP titration study may be done before beginning this treatment to determine the ideal amount of air pressure for individual patients.

For this test, the patient is fitted with a CPAP machine's nasal mask and sensors prior to going to sleep. During sleep, a technologist calibrates the CPAP machine at a low pressure and then gradually raises the pressure at specific intervals while recording sleep parameters. The test's results are later analyzed to determine the patient's optimal air pressure setting.

Split Night Study

This test is recommended for patients with severe OSA, according to the American Association of Sleep Technologists. It helps to diagnose OSA and determine optimal CPAP air pressure in a single night. During the first half of the night, a PSG sleep study is conducted. In the next half, CPAP titration is performed.

Maintenance of Wakefulness Test (MWT)       

According to Stanford Healthcare, this test is commonly used to document successful treatment for a sleep disorder to satisfy requirements from the Department of Motor Vehicles or an employer. It's done at a sleep clinic to evaluate how alert or awake you are during the day.

An MWT indicates how well you can function and stay alert during quiet times of inactivity, states the American Academy of Sleep Medicine. The test is conducted in a quiet, dark room away from distractions. While wearing sensors, the patient undergoes 4 sleep trials of 40 minutes each, with 2-hour break periods. During each trial, the patient has to sit quietly and try to stay awake for as long as possible. Each trial ends if you do not fall asleep within 40 minutes. If you fall asleep during any trial period, you will be awakened after about 90 seconds. 

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Untreated sleep disorders can negatively affect your physical and emotional health. Sleep testing can help you get the answers you need to receive the treatment you deserve. WebMD Connect to Care Advisors are standing by to help.