Maintenance of Wakefulness Test

The Maintenance of Wakefulness Test is used to measure how effective therapies are.  The result is the sleep latency time.  If the therapy is trying to lower excessive daytime sleepiness, the goal is to have the sleep latency be high.  If the goal is to keep people awake when they would otherwise be sleeping (e.g. military applications, certain jobs), the goal is to keep the sleep latency high.

The subject of the test sits upright in bed with electodes connected to his/her body.  Measurements include any or all of: EEG (for measuring brain waves), electrooculography (for measuring activity on the retina), electromyography (for measuring muscles on the head), and electrocardiography (for measuring heart activity).  The room is kept dark.  When the person falls asleep, the time is recorded.

Psychologists who use the MWT generally consider 40 minutes the maximum they will measure on the test.  People who can keep awake that long are considered at very low risk of becoming drowsy.  The shortest time is 8 minutes.  If sleep latency is 8 minutes or less, the person is essentially on verge of sleep.  If sleep latency is only this low a few hours after normal wake-up time, the person is considered likely to have a sleep disorder.  A doctor uses this result to make a diagnosis.

Related: sleep diaries

Sleep Disorders

Dyssomnias

Parsomnias

Insomnia Medications