Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 52 2 2014 02 15 125 129 EN Khosro Sadeghniiat-Haghighi Occupational Sleep Research Center, Tehran University of Medical Sciences, Tehran, Iran. Henry J Moller Sleep Research Unit, University Health Network, University of Toronto, Toronto, Canada. Maryam Saraei Occupational Sleep Research Center, Tehran University of Medical Sciences, Tehran, Iran. Omid Aminian Center for Research on Occupational Disorders, Tehran University of Medical Sciences, Tehran, Iran. Ahmad Khajeh-Mehrizi Baharloo Sleep Center, Baharloo Hospital, Tehran University of Medical Sciences, Tehran, Iran. 2015 10 11 Traffic fatalities are a major cause of morbidity and mortality in Iran. Occupational sleep medicine field needs more cost-effective and applicable tests for screening purposes. This study reports on a pilot screening study for drowsy drivers in an urban Iranian sample of commercial drivers. The Maintenance of Wakefulness Test (MWT) measures the ability to remain awake objectively. Sleep latency in MWT is a reasonable predictor of driving simulator performance in drivers. In this study, we evaluate whether the Epworth Sleepiness Scale (ESS) and MWT are equally useful in drivers with possible Excessive Daytime Sleepiness (EDS). 46 consecutive road truck drivers in a transportation terminal entered into this study. The ESS score of patients with normal and abnormal MWT was 3.24±2.4 and 4.08±3 respectively which was not significantly differenced (P value = 0.34). No significant correlation was found between the ESS and sleep latency in MWT (r=-0.28, 95%CI= -0.58 to 0.02). By using the receiver operating characteristic analysis, the area under the curve was found to be 0.57 (95% confidence interval = 0.37- 0.77) which is not statistically acceptable (P value=0.46). Our finding showed that the MWT and ESS do not measure the same parameter. https://acta.tums.ac.ir/index.php/acta/article/view/4843 https://acta.tums.ac.ir/index.php/acta/article/download/4843/4282