What happens during the Daytime Nap Study?
The daytime nap study or MSLT is a full-day test that is typically performed on the day following an overnight polysomnogram (PSG / sleep study). During the MSLT, you will have 5 opportunities to nap throughout the day at 2-hour intervals. We will be measuring and recording the electrical activity from your brain, eyes, and chin muscles. The amount of time it takes you to fall asleep during each nap is also measured. The test provides an objective measure of daytime sleepiness.
You will be awakened after 20 minutes. If you do not fall asleep within 20 minutes, that nap trial will end. Should you fall asleep within the allotted time, the nap will be extended an additional 15 minutes. You will then have a 90-min break in between naps. You will need to stay awake during the break. If you fall asleep, it could potentially render the test invalid. You may then be subject to repeat the study another day. You are free to watch TV or you may bring a book or computer tablet to keep you busy. You will not be permitted to leave the facility at all once the procedure begins, and absolutely no stimulants or sedatives are allowed (e.g., caffeinated drinks, alcohol, cigarettes).
You will also have multiple wires attached to you, with the primary focus on your brain activity. You will take your first scheduled nap an hour-and-a-half to three hours after you wake up from the overnight sleep study. We recommend that about an hour before your first nap trial begins you eat a light breakfast. We have a refrigerator at each facility where you may store your food.
To get you ready for the test
A sleep technologist will place sensors on your head, face, and chin. These sensors are connected to a computer. The wires are long enough so that you can move around and turn over in bed. A series of sensors will measure whether you are asleep. The sensors also determine your sleep stage and read when you are asleep and awake, and transmit data used to determine when you are in REM sleep. During your test, a low-light video camera will allow the technologist to observe your MSLT from a nearby room.
The nap process is repeated five times. After your second (noon) trial, you can have a light lunch. You will need to bring your own snacks/lunch. The office has a refrigerator you may use. After your final nap trial, the sensors will be removed. You are free to leave when the final trial is concluded, usually between 4:00-5:00 pm.