MSLT (Multiple Sleep Latency Test)

The Multiple Sleep Latency Test is often the most important test for diagnosing narcolepsy. It is a series of five scheduled naps spread across the day. Every two hours, the patient is given an opportunity to sleep for 20 minutes or more. The MSLT is done the day after the polysomnogram so a doctor can determine whether the prior night’s sleep could be affecting the daytime naps.

 

MWT (Maintenance of Wakefulness Testing)

The maintenance of wakefulness test (MWT) is a polysomnographic procedure for the evaluation of daytime somnolence/wakefulness. This test measures one’s ability to stay awake under certain conditions for a defined period of time. It is usually performed during the day following a typical night’s sleep.

The test consists of four sleep trials timed at 2-hourly intervals.

The first trial is performed 2 to 3 hours after your normal wake time. This means that the first trial will normally start around 9 or 10am. You should eat a light breakfast at least one hour before the first trial.

During each trial one has tol sit quietly on the bed with your back and head supported by a pillow and will be asked to look directly ahead and try to stay awake as long as you can. If you fall asleep you will be woken up after 90 seconds and the trial will end if you do not fall asleep within 40 minutes. In between trials one must stay awake and stay out of bed.

The use of caffeine, tobacco, or other medications should be discussed and decided on before the test. The patient should have experienced an adequate quantity and quality of sleep on the night prior to undergoing MWT testing.