Glossary

Multiple Sleep Latency Test [MSLT]

The Multiple Sleep Latency Test (MSLT) is a sleep study (polysomnography) that measures how quickly you fall asleep in a quiet environment during the day. The MSLT typically consists of 4 or 5 scheduled nap sessions, separated by 2-hour breaks.

During each nap session, you lie in bed in a dark, quiet room and try to go to sleep. The time that it takes you to fall asleep is called the sleep latency. You‘ll be allowed to sleep for a maximum of 15 minutes during each session. You’ll be awakened if you don’t wake up on your own. If you don’t fall asleep within 20 minutes, the nap session will end.