Multiple Sleep Latency Test (MSLT)
The multiple sleep latency test (MSLT) is a nap study used to measure how quickly a patient falls asleep in quiet situations during the day, and is based on the idea that an individual should fall asleep in a shorter amount of time as the feeling of sleepiness increases. The test is used to evaluate individuals who are thought to have narcolepsy.
The MSLT charts a patient's brain waves and heartbeat and records eye and chin movements. It is typically conducted after an overnight sleep study, and consists of up to five nap trials with two hours between each. The first nap trial begins between one and three hours after a patient wakes up from the overnight sleep study.
Sensors that read brain-waves and eye movement are attached to a patient's head, face and chin. The patient will be asked to lie in bed and try to fall asleep. Data from the sensors determine how fast the patient falls asleep. After sleeping 15 minutes, the patient is awakened. Between nap trials, the patient is required to stay out of bed and stay occupied so that he or she will stay awake until the next trial begins. The process is repeated up to five times during the study.