Maintenance of Wakefulness Test
Why the Maintenance of Wakefulness Test is Used
The Maintenance of Wakefulness Test (MWT) is a diagnostic tool used by sleep specialists to assess wakefulness during the day. Wakefulness is defined as feeling alert or staying awake for any specified duration of time. During the MWT you are asked to stay awake for as long as possible while remaining inactive in a setting designed to induce sleep. Ultimately, results of the test can show whether a patient is successfully overcoming sleepiness during and after treatment for certain sleep disorders. Specifically, the MWT is often used to track improvement in narcoleptics and hypersomniacs.
Most people who undergo the maintenance of wakefulness test have already been diagnosed with a sleep disorder. They have started on a treatment plan, and their sleep doctors need to know whether the treatment is working properly. An MWT allows physicians to see whether excessive daytime sleepiness or other symptoms have improved since treatment began. The MWT can also be ordered when it is unclear whether a person suffering from sleep-related problems is alert enough to drive or regularly engage in other daytime activities.
How the Maintenance of Wakefulness Test is Performed
In order to ensure that the MWT is primarily measuring wakefulness, sleep specialists try their best to control outside factors that may make it easier for you to fall asleep or stay awake. They will control the amount of light that you are exposed to, the temperature of the room and any surrounding noise and activity. Nonetheless, if you are naturally depressed or anxious, or if you have certain medications or foods in your system, your test results may not be as objective. Typically before an MWT is performed, the sleep doctors attending to you will ask you to avoid cigarettes, caffeine and any medications that may cause the test results to be less accurate. In some cases, a drug test is performed prior to the MWT just to ensure that your system is clean.
Though it is not usually necessary, some people undergo an overnight polysomnography the night prior to their maintenance of wakefulness test, in which case the MWT starts 1 to 3 hours after you wake up and have a light breakfast. Going this route can ensure that you get the proper amount of sleep the night before the MWT to produce accurate results. If you are able to receive a full night’s sleep in the comfort of your own home, then an overnight sleep study before the MWT is not necessary.
Overall, the MWT collects data from 4 sleep trials. You will be asked to sit in a bed located in a dimly lit and quiet room. You will have sensors attached to your head, face and chin, which monitor your vital signs and how awake or sleepy you are during the test. During each trial, you are not allowed to perform any activities that may stimulate you or keep you from falling asleep. You simply sit in bed with you head leaned back onto the pillow and try to remain awake for as long as you can.
If you fall asleep, a technician will come and wake you up within a couple of minutes. The time it took you to fall asleep would be recording, and that trial would be considered complete. If during a trial you stay awake for 40 minutes or more, then the trial ends. This happens between 40 to 59 percent of the time, according to sleep experts. Generally speaking, sleepers not afflicted by a disorder can fall asleep about 8 to 10 minutes into the MWT. Falling asleep too soon before or too long after this mark would be considered abnormal.
You will have to wait about 2 hours in between each of the 4 trials. During these intervals, you need to leave the bed and occupy yourself with activities in order to stay awake. Sometimes the sleep center will give you a snack or light lunch. After the 4 trials are over, you may leave the sleep center for the day. Most likely you will schedule a follow-up appointment with a doctor who can discuss the test results with you. For more information about monitoring your sleep disorders treatment with the Maintenance of Wakefulness Test, contact board-certified sleep doctors listed in our medical directory.