What is a 'wake up' test and when is it performed?

MWT. A maintenance of wakefulness test (mwt) is usually done after someone has been treated for a sleep disorder, like obstructive sleep apnea or narcolepsy. It tests your ability to stay awake. For certain occupations, state licensing agencies will require them to ensure proper treatment, for occupations such as truck drivers, railroaders and others involved in the transportation industry.
Awake during surgery. Sometimes, particularly during neurosurgery, it is necessary to check a response or function. In a wake up test the level of anesthesia is purposefully lightened to allow the patient to wake enough to respond. Pain is controlled with analgesics, or local anesthetics. After the response is checked, anesthesia is then increased, and the patient "goes back to sleep".