Testing for Narcolepsy

Sleep doctors rely on a test called a Multiple Sleep Latency Test (MSLT), which is a nap study, to diagnose narcoleptics.

The MSLT is used to see how quickly one falls asleep in quiet situations during the day. Most people with narcolepsy fall asleep in an average of less than 5 minutes during the MSLT nap trials. Some take longer than 5 minutes to fall asleep. Yet, there are also people without narcolepsy who fall asleep in less than 5 minutes.

The study is based on the idea that you should fall asleep in a shorter amount of time as your feeling of sleepiness increases. The MSLT charts your brain waves and heartbeat and records your eye and chin movements. The study also measures how quickly and how often you enter the rapid-eye-movement (REM) stage of sleep. Results of the nap study are routinely used to detect other sleep disorders as well.