Types of Sleep Study Tests

There are several types of sleep study tests conducted at the Washington University Sleep Medicine Center, including: all-night sleep study, continuous positive airway pressure (CPAP) titration, split study, multiple sleep latency testing, maintenance wakefulness testing and epilepsy monitoring.

Most of the sleep studies are performed as outpatient procedures at the Sleep Medicine Center. All of our sleep rooms are private and have adjoining full bathrooms. Some patients may be required to have home sleep testing. Usually this is dictated by a patient’s insurance company. Also, if clinically indicated, an in-patient study can be ordered and the patient will be monitored at Barnes-Jewish Hospital.


The Sleep Lab has highly qualified Registered Sleep Technologists who assist the physicians with the sleep studies. They utilize the latest and most comprehensive, diagnostic technology.

Round-the-clock sleep studies are offered by the Sleep Medicine Center ensuring the best testing conditions possible. The 24-hour scheduling allows patients who are involved in shift work to sleep during their normal sleep periods while a sleep study is performed.
In special cases, a caregiver can stay overnight in an adjacent room to the patient. Requests must be approved by the Sleep Provider and arrangements must be made in advance.

During the study, you will be monitored. There will be digital video recordings of you sleeping. These video recordings are completely confidential as all data being collected on patients at the Sleep Medicine Center. Please note it’s not possible to obtain your video records because it requires a special software program.

All-night Sleep Study 

An all-night sleep study (also known as an all-night polysomnogram) allows Sleep Providers to measure how much and how well you sleep. Small electrodes are attached to your skin with small stick pads. They record and measure your breathing patterns, blood oxygen levels, muscle activity and heart rhythm. Other measurements may be included at the discretion of the ordering Sleep Provider.

Sleep Technologists will be evaluating the data during the actual recording. At the end of the study, a Sleep physician will thoroughly analyze the data and determine if the patient has a sleep disorder and identify the most effective treatment. Patients will typically get their results the following morning.

CPAP Titration

After your all-night polysomnogram, the Sleep physician may determine that you need CPAP therapy.

This sleep study is very similar to the all-night polysomnogram but CPAP therapy will be introduced. The CPAP machine is a small machine that blows filtered air through a plastic hose and into a mask you must wear during the night. Adjustments to the pressure of air will made throughout the study to determine the lowest pressure needed to keep your airway open while you sleep.

Split Study

This study is an all-night polysomnogram and CPAP Titration study done in one night. The CPAP titration study can only be started if certain conditions are met during the polysomnogram so we cannot guarantee that both can be done on the same night.

Multiple Sleep Latency Testing

This test is often done following an all-night sleep study. It’s performed to evaluate how often and how quickly a patient falls asleep in quiet situations during the day. This test is used to document the presence and severity of daytime sleepiness, as well as to detect sleep architecture abnormalities associated with narcolepsy.

Electrodes similar to those in the polysomnogram will be used to measure brain, heart and muscle activity as well as eye movements.
The test takes about 7 hours to complete. Patients are instructed to nap for about 20 minutes every two hours. They will have 5 naps and each nap will begin after a 2 hour wake period. The first nap usually takes place around 10:00AM. A sleep technologist will continually be monitoring the patient to ensure they are staying awake during the 2 hour wake period and while they are napping.

Maintenance Wakefulness Testing

The maintenance wakefulness test is similar to the multiple sleep latency test, but instead of lying down in bed, the sleep technologist will ask the patient to sit in bed and to stay awake rather than sleep.

There will be five sessions to this test. Each session will last approximately 40 minutes. Patients will have a session once every two hours beginning at approximately 10:00 am. The last test should be at approximately 6:00 pm and then the patient will be free to leave around 7:00 pm.
This test is often used in the transportation industry to evaluate ability to drive or fly safely.

Epilepsy Monitoring

This is done only in conjunction with the all-night polysomnogram or the multiple sleep latency test. The Sleep Provider will make the determination of running this test at the time of the patient’s initial consultation

In cases where seizures are suspected, a more extensive array of electrodes may be placed on the scalp and continuous EEG and video monitoring performed either at night or during the day, depending upon the nature of the presenting complaints.