A normative study of the maintenance of wakefulness test (MWT)

Abstract

The maintenance of wakefulness test (MWT) is a daytime polysomnographic procedure which quantifies wake tendency by measuring the ability to remain awake during soporific circumstances. We present normative data based on 64 healthy subjects (27 males and 37 females) who adhered to uniform MWT procedural conditions including polysomnographic montage, illuminance level, seating position, room temperature, meal timing, and subject instructions. When allowed a maximum trial duration of 40 min, subjects' mean sleep latency to the first epoch of sustained sleep was 35.2 +/- 7.9 min. The lower normal limit, defined as two standard deviations below the mean, was 19.4 min. Calculation of data on the basis of a maximum trial duration of 20 min and sleep latency to the first appearance of brief sleep (a microsleep episode or one epoch of any stage of sleep) yielded a mean sleep latency of 18.1 +/- 3.6 min and a lower normal limit of 10.9 min. Sleep latency scores were significantly higher than those previously reported in patients with disorders of excessive somnolence. Therefore, the MWT appears to be a useful procedure in differentiating groups with normal daytime wake tendency from those with impaired wake tendency and in identifying individuals with pathologic inability to remain awake under soporific circumstances.

Vigilance, alertness, or sustained attention: physiological basis and measurement

“…Sleepiness as assessed on these tests correlates with performance on sustained attention tasks (Carskadon and Dement, 1979). However, the correlations are not great (George et al, 1996;Harrison and Horne, 1996), in part related to the lack of ideal definition of sleep onset, varying from a relatively long, 3 consecutive 10-s epochs of stage 1 sleep to an epoch of stage 1 lasting several to 15 s sometimes referred to as a microsleep (Doghramji et al, 1997;Salinsky, 1996;Valley and Broughton, 1983). The lack of a very high correlation between sleepiness and vigilance performance is also because inattention is only partially related to sleepiness (Sangal and Sangal, 2004).…”

Diretrizes brasileiras para o diagnóstico de narcolepsia

“…68,69 It is not a diagnostic test for narcolepsy and the American Academy of Sleep Medicine recommends the MWT to evaluate 65 the capacity of a patient to remain awake when there is a safety risk to the patient or others 66,67 and to determine the response to treatment in patients with ES 66,67 5) Conclusions of the neurophysiological evaluation The PSG and MSLT are useful to confirm the narcolepsy diagnosis. If PSG followed by the MSLT is negative on separate occasions, the diagnosis of ES due to narcolepsy is excluded.…”

Comparison of Sleep Latency Measured by the Oxford Sleep Resistance Test and Simultaneous EEG in Japanese Patients

“…When a sleep latency of 20 minutes was set as the cut-off value for the "presence of sleepiness" based on the findings of a previous study by Sagaspe et al [4], SL OSLER was <20 minutes in seven patients (ESS=11.7 ± 5.5; three patients with ESS<11 [range, [3][4][5][6][7][8][9][10], four patients with ESS ≥ 11 [range, [12][13][14][15][16][17][18]) and ≥ 20 minutes in 10 patients (ESS=8.5 ± 5.1; eight patients with ESS<11 [range, [3][4][5][6][7][8][9][10], two patients with ESS ≥ 11 [range, [17][18]). Furthermore, an SL OSLER cut-off of 20 minutes resulted in sensitivity and specificity values of 1.0, while an ESS cut-off of 11 resulted in a sensitivity of 0.57 and specificity of 0.8.…”

“…The Epworth Sleepiness Scale (ESS) [6] and Stanford Sleepiness Scale (SSS) [7] are widely utilized for the subjective assessment of EDS in both daily clinical practice and clinical studies. Objective methods of EDS assessment include the Multiple Sleep Latency Test (MSLT) [8], which measures the time to sleep onset, and the MWT [9], which measures the duration of sustained wakefulness.…”