Tests and Diagnosis

Tests and Diagnosis

The Emory Sleep Center uses some of the most sophisticated and technologically-advanced diagnostic tools available to diagnose patients with sleep disorders. These include the following in-lab diagnostic tests:

Polysomnogram (PSG)

A polysomnogram records information about an individual’s sleep. Sensors are gently attached to a patient’s body obtaining, while the patient sleeps, a continuous recording of brain waves, eye movements, muscle tone oxygen levels in the blood, heart rate and rhythm, leg and body movements, sounds made while sleeping, breathing effort and airflow through the nose and mouth. If other disorders are suspected, additional information is recorded. The recording is painless, however patients with sensitive skin may notice mild irritation from the sensor adhesive. This equipment can be disconnected during the night, allowing a patient to get out of bed or use the bathroom.

A polysomnogram generally takes place during an overnight stay in the Sleep Center. If you routinely sleep during the day or evenings, your testing hours can be customized with advanced planning. Each of the Sleep Center’s bedrooms are private with an adjoining private bathroom and shower, and patients are monitored from an adjacent control room by an experienced sleep technologist.

Positive Airway Pressure (PAP) Titration Study

If Polysomnography testing shows an individual demonstrates sleep apnea, a PAP titration study will be ordered to initiate treatment. If the sleep apnea is severe, this may take place during the first overnight sleep study. Otherwise, the individual will need to return for a second all-night sleep study before starting CPAP (Continuous Positive Airway Pressure) therapy. During the titration study, as the patient sleeps using the CPAP machine, the sleep technologist will record data including the patient’s breathing, while making adjustment to the CPAP machine during the night. These adjustments do not require the technologist to awaken the patient. The technologist will use this information to find the level of air pressure keeping the airway open and helps the patient to breathe easily and reduce the number of times breathing stops to allow better and safer sleep.

Multiple Sleep Latency Test (MSLT)

The MSLT is the standard way to quantify sleepiness and diagnose disorders of excessive sleepiness. Generally used to evaluate for narcolepsy, this type of polysomnogram is conducted after an overnight polysomnogram to investigate other possible causes of excessive sleepiness (e.g. sleep apnea or periodic limb movements during sleep) and make sure the patient is not lacking REM (rapid eye movement) sleep. The MSLT begins one-and-a half to two hours after waking up in the morning, with the patient being encouraged to sleep five more times, once every two hours.

Multiple Wakefulness Test (MWT)

This polysomnogram is used to evaluate the ability to stay awake during the day. The test is a variation of the MSLT, where the patient is instructed to attempt to stay awake sitting up in bed, rather than napping, every two hours. MWT testing is available for testing required by the Department of Transportation, Federal Airway Administration and as required by other organizations and employers.

Home Sleep Apnea Testing (HSAT)

Home sleep apnea testing (HSAT), also referred to as out-of-center sleep testing or portable monitoring, is a diagnostic test used to diagnose obstructive sleep apnea (OSA). OSA is a disorder characterized by repetitive episodes of apnea or reduced inspiratory airflow due to upper airway obstruction during sleep. It has evolved as an alternative to overnight, attended, in-laboratory polysomnography (PSG) in selected patients. Advantages of HSAT include its convenience (it can be performed in the patient's home or in a hospital room). This test consists of a 20-minute visit with our clinical staff to advise the patient on how to properly apply and use the equipment at home.



Actigraphy is measured by a watch-like device worn on the wrist to monitor rest and activity cycles. These devices help estimate sleep and wake times, and are used with a sleep diary. Patients are usually asked to wear the device for one-to-two weeks and frequently done prior to overnight and day sleep studies.