Dr. Po-Yang Tsou, MPH, MD

The most widely performed sleep test is the traditional polysomnogram (PSG). This test is typically used to determine whether patients have sleep apnea (lapses in breathing while asleep). Polysomnograms are conducted overnight in a specialized sleep clinic or sleep center, where a patient enters the sleep center and is assigned to a room with a bed, medical equipment, and monitoring system. An overnight sleep technician attaches electrodes to the patient's head, chest, and legs. This application process lasts for around an hour. A sleep technician watches and evaluates the patient as they sleep. Objects such as a comfortable pillow from home, toiletries, and small personal items may be helpful in easing patients into sleep in unfamiliar surroundings.

Patients receive their physician-interpreted sleep study results within a few weeks of the test. If sleep apnea is detected, patients may be asked to return for a titration sleep study. A titration study involves the same procedures and electrode placement of a polysomnogram, but also includes a mask attached to a CPAP (continuous positive airway pressure) machine. The CPAP machine brings pressurized air to the patient. The technician may monitor and adjust the CPAP's air pressure throughout the night. The purpose of a titration study is to determine the appropriate air pressure for patients with obstructive sleep apnea (blocked upper airway).

A split night study combines the polysomnogram and titration sleep studies into two sessions on the same night. Split night studies enable patients to complete both studies quickly instead of waiting weeks in between tests and may expedite the interpretation of results and treatment.

Multiple sleep latency test (MSLT) measures how fast someone is able to fall asleep. Unlike other sleep tests, this test is performed during the day. It may take place after an overnight sleep study. The MSLT test monitors napping and potential for daytime sleepiness and exhaustion.

At-home sleep tests are fully conducted by patients in their own homes. Patients attach fewer electrodes, a breathing sensor, a microphone, and a data collection device to themselves and sleep in their own beds. The following morning, patients gather the data collection device and return it to their medical providers. While at-home sleep tests are convenient, they are not recommended for patients with severe sleep problems. At-home sleep tests are less precise than clinical tests and do not measure brain activity.

Sleep studies are essential to helping patients receive accurate sleep disorder diagnoses and proper treatment. A sleep study can be the first step towards higher quality sleep and physical health.