The multiple sleep latency test (MSLT) tests for excessive daytime sleepiness by measuring how quickly you fall asleep in a quiet environment during the day. Also known as a daytime nap study, the MSLT is the standard tool used to diagnose narcolepsy and idiopathic hypersomnia.
The MSLT is a full-day test that consists of five scheduled naps separated by two-hour breaks. During each nap trial, you will lie quietly in bed and try to go to sleep. Once the lights go off, the test will measure how long it takes for you to fall asleep. You will be awakened after sleeping 15 minutes. If you do not fall asleep within 20 minutes, the nap trial will end.
Each nap will be taken in a dark and quiet sleep environment that is intended for your comfort and to isolate any external factors that may affect your ability to fall asleep. A series of sensors will measure whether you are asleep. The sensors also determine your sleep stage.
A maintenance of wakefulness test is administered over the course of a day at a sleep laboratory and is used to measure how alert a patient is during the day and if they are capable of staying awake for a period of time in a quiet, relaxing, stimulation free environment.
During the test, patients are given 4-5 trials of 40 minutes of relaxing in a quiet, dimly lit bedroom during which time they are asked to simply sit still while looking forward, and not do anything stimulating that could intentionally keep them awake (no talking aloud, singing, reading, pinching themselves, etc.).