Types of Sleep Studies

Polysomnogram (overnight study)
A polysomnogram (PSG) is the most reliable test used to diagnose certain sleep disorders. It measures abnormalities in the sleep cycle. This test can also help to rule out that the person’s symptoms stem from another medical condition.

The test is an overnight study that is very easy to have done; there is virtually little or no discomfort. Electrodes are placed on the skin and scalp. These electrodes are then connected to recording equipment to monitor and record the following body functions during sleep: airflow and respiratory effort, blood oxygen levels, blood pressure and heart rate, electrical activity in the brain, eye movement and muscle movement.

CPAP Titration (overnight study)
A CPAP titration study is an overnight sleep study that is for treatment rather than diagnosis. When you come in you are fitted for a CPAP mask and then hooked up to the polysomnography equipment. During the night the pressure of the air coming from the CPAP machine is gradually increased until your breathing is normalized and your correct CPAP pressure has been determined. You will be trained that night for proper use and care of your CPAP machine.

Multiple Sleep Latency Test (daytime study)
A multiple sleep latency test (MSLT) is conducted, along with a polysomnogram, to confirm or rule out narcolepsy. It is a test done during the daytime that monitors a series of naps to reveal a person’s severity of sleepiness and whether REM sleep (deep sleep during which a person dreams) intrudes inappropriately throughout waking hours.

The test is usually done immediately after an overnight study. You will remain wired with most of the wires from the polysomnogram done the night before. A series of five naps are taken at two-hour intervals. The test is usually done by 5 p.m. There is little or no discomfort from the MSLT.

Maintenance of Wakefulness Test (daytime study)
A Maintenance of Wakefulness Test (MWT) is conducted along with a polysomnogram to determine your level of daytime sleepiness after treatment for narcolepsy or sleep apnea. This test is generally used for commercial drivers, pilots and people who work around heavy equipment to ascertain ability to perform their job safely.

The test is usually done immediately after an overnight study. You will remain wired with most of the wires from the polysomnogram done the night before. A series of four “naps” are taken at two-hour intervals. Each nap requires the patient to sit in a chair for 40 minutes and try to remain awake. The test is usually done by 5 p.m. There is little or no discomfort from the MWT.