The Maintenance of Wakefulness Test of Poceta et al. (1992) examines the ability to stay awake in a sleep-inducing situation. The patient sits in a darkened room on a comfortable chair or on the bed and will be asked to refrain movements (e.g., grimacing, shaking), which may prevent falling asleep to refrain (Hartse et al. 1982, Mitler et al. 1982). Three to four times a day electrophysiological recordings (C3/A2, C4/A1, EOG and EMG) are recorded in 2-hour intervals of 20 minutes. The earliest start of the first test procedure should be scheduled two hours after waking. As with the MSLT test history is filmed with a video camera. Evaluated will be the sleep latency from the moment "light off" until the onset of the first two epochs of sleep stage 1 or 2.
In various standardization studies, inconsistent cut-off values were found from 13.5 to 18 minutes (Banks et al. 2004, Rühle 2005). Reasons for the different standard values according to Shreter et al. (2006) are that the test exercises have a significant influence on occasion staying awake in the test situation. So they provided proof that the sleep latency on the MWT was deliberately suppressed because the OSAS patients were afraid to get the license revoked. In considering the relationship between the MWT and ESS were calculated a satisfactory correlation of r = .48 (p < .001), with the common variance of the two devices was only 23% (Sangal et al. 1997b).
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