Multiple Sleep Latency Test

The Multiple Sleep Latency Test isolates you from outside factors that can affect your ability to fall asleep. These factors, according to the American Academy of Sleep Medicine, include such things as temperature, light, noise, and activity. Other factors that can still affect the results of the study include anxiety, tension, depression, age, caffeine, drugs and medications and the amount of sleep prior to the study.

Here's how the MSLT test for narcolepsy works:

- You will be screened for drugs before you take the test
- You should keep a sleep diary documenting signs of narcolepsy for a week before the test
- Smoking should be stopped at least 30 minutes before the test
- You will not be allowed to have any drinks with caffeine during the study. You will also not be able to see any bright sunlight. Outside factors that might affect your sleep are limited. Your room is made dark and quiet. The room temperature is set at your personal comfort level.
- The daytime nap study is taken right after you do an overnight sleep study. For the MSLT to be accurate, you should have had a total sleep time of at least six hours during the overnight sleep study.
- The MSLT consists of five nap opportunities with breaks lasting for two hours in between them.
- Sensors are placed on your head, face, and chin. They send tiny electrical signals to a computer. The signals show when you are asleep and awake during the study.
- You will not feel any pain during the MSLT. A low-light video camera allows a technologist to see you from a nearby room. You will be asked to move your eyes, clench your teeth and turn your head. This will make sure that the sensors are working.
- For each nap trial, you are asked to lie quietly in bed and try to go to sleep. Then the lights are turned off. Once the lights are out, the test will measure how long it takes you to fall asleep. Your vital signs will continue to be measured as you sleep.
- After sleeping for 15 minutes, you will be awakened. Each trial will end if you do not fall asleep within 20 minutes. Between nap trials, you will have to stay out of bed and occupy yourself so that you remain awake. A light lunch should be provided right after the end of the second (noon) trial.
- After the last nap trial, you will test the sensors again, and then they will be removed. This will complete the study, and you will be free to go.