The Maintenance of Wakefulness Test (MWT) measures a person’s ability to stay awake in a quiet, dark and nonstimulating room for a period of time. This test is usually given to a person receiving therapy for conditions causing daytime sleepiness which have been diagnosed i.e. sleep apnea.

The MWT requires a person to stay awake during four 20 to 40 minute periods with each period being 2 hours apart. The person sits in a chair or is seated in a bed with the back and head supported by a bolster pillow for comfort. Sleep rooms are dark and quiet during testing except for a 7.5-W nightlight used as a light source. The person should look directly ahead and not at the light for 20 minutes. Recording devices are used to determine how awake the person remains during the 20 to 40 minute period. Patients are instructed to avoid extreme behaviors to stay awake.

The use of caffeine, tobacco, or other medications should be discussed and decided on before the test. The patient should have experienced an adequate quantity and quality of sleep on the night prior to undergoing MWT testing.