Sleep Disorders - Everything you Need to Know about Sleep Deprivation


Daytime studies on sleep monitor patients during their active hours. Learn about these studies, such as the multiple sleep latency test (MSLT) and the maintenance of wakefulness test (MWT).

Multiple Sleep Latency Test (MSLT)

A multiple sleep latency test is a sleep disorder test that may help doctors diagnose conditions such as excessive sleepiness, or narcolepsy. The MSLT study is a nap study that measures sleepiness by monitoring how soon an individual falls asleep during active hours. Sensors are placed on the scalp, face and chin to record brain activity, heart rate and eye and chin movements.

During an MSLT study, you’ll quietly lie in bed and try to fall asleep; the sensors measure how long it takes you to fall asleep, as well as vital signs. After 15 minutes of sleep, you’re awakened and encouraged to move around to stay awake until the next test period. A sleep center technician oversees the test, which is given five times throughout the day. This daytime sleep disorder test is generally administered immediately after a nocturnalpolysomnogram.

In addition to measuring how long it takes you to fall asleep, MSLT study data sheds light on the types of sleep you experience, including rapid eye movement (REM) and the three stages of non-rapid eye movement (non-REM) sleep, which follow patterns.

Maintenance of Wakefulness Test (MWT)

Also administered during active hours, the MWT can help doctors determine if individuals with sleep disorders are responding well to treatment, as evidenced by reduced sleepiness. Sensors placed on the scalp, face and chin assess how long a patient is able to stay awake over a period of time.

The exam commonly consists of about four trials lasting approximately 40 minutes each. During a trial, you’ll sit quietly, looking directly ahead and trying to stay awake. If you fall asleep, you’ll be awakened after 90 seconds. Rather than determining why patients can’t fall asleep, this test focuses on a patient’s ability to stay awake. The maintenance of wakefulness test is often administered on people who drive or operate heavy machinery in their work.


American Academy of Sleep Medicine. (2010). Sleep studies. Retrieved December 15, 2010, from

National Heart Lung and Blood Institute. (n.d.). What to expect during a sleep study. Retrieved December 15, 2010, from

 Posted on : June 1, 2014