The maintenance of wakefulness test in normal healthy subjects

Abstract

Study objectives: The Maintenance of Wakefulness Test (MWT) examines an individual's ability to stay awake in an environment of decreased sensory stimulation. Only 1 previous study has systematically examined the MWT in normal healthy subjects.

Setting: Sleep disorders unit laboratory

Participants and design: 31 subjects (mean age 48.5 years, SD 9.6; 8 women) were randomly selected via the telephone directory within a 30-km radius of the test centers. They answered a general screen for health complaints (respiratory, cardiovascular, and psychiatric disorders) and sleep difficulties (snoring).

Interventions: N/A.

Measurements and results: Overnight polysomnography and a 40-minute MWT the following day were performed on all subjects. Mean sleep latency to the first epoch of unequivocal sleep during the 40-minute trial MWT was 36.9 +/- 5.4 (SD) minutes. The lower normal limit, defined as 2 SD below the mean, was therefore 26.1 minutes. Mean sleep latency for the first 20 minutes of the trial (with sleep latency defined as time to the first appearance of 1 epoch of stage 1 sleep or a 10-second microsleep) was 18.6 +/- 2.3 minutes, with a lower normal limit of 14.0 minutes.

Conclusions: The mean results are consistent with previously published normative data. However, the SDs found in this study are smaller, and, thus, the lower normal limit suggested here is 4 to 6 minutes longer. The subjects in this study were randomly selected from the general population and may, therefore, be a truer representation of the normal population than in the previous study in which subjects were recruited via hospital advertisements and word of mouth.