Multiple Sleep Latency Test (MSLT)
The Multiple Sleep Latency Test (MSLT) is an objective measure of sleepiness and is conducted to measure how long it takes you to fall asleep. This test is the standard way to quantify sleepiness and diagnose disorders of excessive sleepiness such as narcolepsy. After being asked to try to fall asleep for each nap test, sensors on the head and chest record your brain wave activity, eye movements, muscle contractions, and heart activity to accurately detect if you fall asleep.
The test consists of four or five 20-minute nap opportunities that are scheduled two hours apart. The test is often performed after an overnight sleep study. During the test, data such as the patient's brain waves, EEG, muscle activity, and eye movements are monitored and recorded. The entire test normally takes about 7 hours.