Validation of <scp>OSLER</scp> Test Against Maintenance of Wakefulness Test and the Association With Subjective Measures of Sleepiness

The ability to stay awake is crucial in life and can be compromised by insufficient sleep and medical conditions. Measuring alertness is important for evaluating driving ability and the Oxford Sleep Resistance (OSLER) test may provide an easy way for assessment. The study population included 40 professional truck drivers who participated in the Maintenance of Wakefulness Test (MWT) between 2000 and 2002. Half of these subjects had sleep latency less than 33 min in the MWT. All subjects completed a questionnaire, underwent interviews, participated in both the MWT and OSLER test on consecutive days and filled in the Karolinska Sleepiness Scale (KSS) before each MWT and OSLER test session. Altogether, 39 subjects successfully completed both the MWT and OSLER test in random order. The MWT took place after polysomnography. The mean sleep latency in the MWT was 38.7 min while the mean sleep latency in the OSLER test was 38.9 min. If the sleep latency in the OSLER test exceeded 33 min, it was highly likely that the sleep latency in the MWT would also be normal (> 33 min). The OSLER test appears to be a reliable objective measure for assessing the ability to stay awake in professional drivers and is easier to administer than the MWT, which still remains the gold standard.