Sometimes you may need to stay after your sleep study to take a daytime nap study. This study is called a Multiple Sleep Latency Test (MSLT). It is used to see how quickly you fall asleep in quiet situations during the day. The MSLT is the standard tool used to evaluate people who are thought to have narcolepsy. It may also be used to see if a person has hypersomnia. It begins between 1.5 and three hours after you wake up from the overnight sleep study. It consists of five nap opportunities with breaks lasting for two hours in between them. A shorter four-nap study may also be used. Your sleep patterns are monitored with most of the same recording equipment used the night before. The time it takes you to fall asleep will be measured. The kind of sleep you get during each nap will also be recorded. This is a valuable tool to help determine why someone is very sleepy during the day.

Be sure to plan ahead for a longer stay when you are scheduled for a nap study. You can call the center in advance to find out about breakfast and lunch plans. They can also let you know about what time the MSLT will be finished. Between nap trials, you will have to stay out of bed and occupy yourself so that you remain awake. You may want to bring things with you to work on or to entertain yourself. You can also ask about watching TV or videos between naps.