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Testing Procedures

The Center for Sleep Medicine at NewYork-Presbyterian/Weill Cornell Medical Center provides the full range of diagnostic procedures to determine the source of sleep disturbances. An overnight sleep study, also called polysomnography (PSG), is the principal means of both diagnosing sleep disorders and determining the effectiveness of treatment. We perform this test on-site during a patient's usual sleep hours. 

The sleep studies we offer include:

Overnight sleep study

After arriving at the Center for Sleep Medicine, patients go to sleep at their normal bedtime. They spend the night in one of our comfortable private monitoring rooms and wake up at the usual time. Private bathrooms are available in all of our overnight sleep study rooms, enabling patients to shower and get ready as they would on a typical morning. Patients who require further testing may also be scheduled to stay at the Center for a daytime sleep study. 

In some patients, the overnight sleep study will include a treatment trial with a positive airway pressure (PAP) device, which is attached to a mask interface. There are different types of PAP treatments available, including continuous positive airway pressure (CPAP), bi-level positive airway pressure (BIPAP), or a device called Adaptive Servo Ventilation (ASV), which provides ventilation tailored to each patient's breathing pattern. These are selected according to patients' needs. 

PDF iconInstructions for an Overnight Sleep Study

Positive Airway Pressure (PAP) Nap

This study is available for patients who experience difficulty adjusting to a PAP device. During a PAP Nap, patients have a one-on-one session with a specialized technician and are allowed to take a nap of two or more hours with a mask interface, receiving guidance from our specialists to help them adjust to this treatment for sleep apnea.

Daytime sleep study

A patient's degree of drowsiness and/or wakefulness during the day can be assessed using specific daytime tests such as the multiple sleep latency test (MSLT) or maintenance of wakefulness test (MWT). The MSLT consists of a series of naps taken throughout the day, and provides an objective assessment of daytime sleepiness. It is typically done the day after an overnight sleep study. The MWT measures a patient's ability to stay awake. These tests are indicated in specific situations as determined by the sleep specialist during the patient's evaluation.

PDF iconInstructions for Daytime Testing

Home Sleep Study

In some cases, a home sleep study may be indicated to evaluate for sleep apnea. This is a limited test that does not monitor sleep, but breathing during sleep, using a portable equipment. In order to be set up with a home sleep test, patients will come for a daytime visit with a sleep specialist to be instructed on how to wear the portable device. During that night, while at home, patients will attach the equipment as instructed in order to record data while they sleep. On the following day, the equipment is returned to the center for data download and interpretation. 

The home sleep study may be especially useful for patients who prefer to be tested in the familiar surroundings of their own homes and in cases where no other sleep disorder, besides sleep apnea, is of concern

PDF icon Instructions for a Home Sleep Study

Nocturnal Oximetry

Blood oxygen levels may be reduced in patients with sleep apnea and other respiratory problems during sleep. Nocturnal oximetry is a test to measure oxygen levels in the blood during sleep. It is routinely performed during sleep studies at the Center for Sleep Medicine; however, it can also be performed separately to monitor breathing and treatment effectiveness at home, using an easy-to-use portable device. The Center provides some patients with a home oximetry test (a clip-like device that slides onto a finger) to measure blood oxygen levels while the patient sleeps at home. This test can also be performed by the patient's PAP provider or home care company. 


Actigraphy records activity and movement using a small monitor or motion detector generally worn on the wrist throughout the day and night, much like a wristwatch. The test is conducted over one to two weeks during the patient's usual routine at home, with the intent of gathering more information about sleep patterns.

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