The Epworth Sleepiness Scale for Screening of the Drowsy Driving: Comparison with the Maintenance of Wakefulness Test in an Iranian Sample of Commercial Drivers

  • Khosro Sadeghniiat-Haghighi Mail 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.
Epworth Sleepiness Scale, Maintenance of Wakefulness Test, Commercial drivers


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.


Murray C, Lopez A, editors. The global burden of disease: a comprehensive assessment of mortality and disability from diseases, injuries and risk factors in 1990 and projected to 2020. Global Burden of disease and Injury Series, 1st ed. Cambridge: Harvard University Press; 1996: p. 60.

WHO Statistical Information System (WHOSIS). WHO. (Accessed in Feb 14, 2014, at

Montazeri A. Road-traffic-related mortality in Iran: a descriptive study. Public Health 2004;118(2):110-3.

Sanaei-Zadeh H, Vahabi R, Nazparvar B, et al. An epidemiological study and determination of causes of traffic accident-related deaths in Tehran, Iran (during 2000-2001). J Clin Forensic Med 2002;9(2):74-7.

Islamic Republic News Agency, Chief of Irainain Center of police Control road traffic. (Accessed in Feb 14, 2014, at

Christensen-Rand E, Hyder AA, Baker T. Road traffic deaths in the Middle East: call for action. BMJ 2006;333(7573):860.

Peden M, Scurfield R, Sleet D, et al. World report on road traffic injuries prevention. World Health Organization. (Accessed in Feb 14, 2014, at

Horne J, Reyner L. Vehicle accident related to sleep: a rewiew. Occup Environ Med 1999;56(5);289-94.

Zomer J, Lavie P. Sleep-related automobile accidents- When and who? In: Horne JA, editor. Sleep‘90. 1st ed. Bochum: Pontenagel Press; 1990: 448-51.

Horne JA, Reyner LA. Sleep related vehicle accidents. BMJ 1995;310(6979):565-7.

Jennie C, Robyn N, Shanti A, et al. Driver sleepiness and risk of serious injury to car occupants: population based case control study. BMJ 2002;324(7346);1125-8.

Lyznicki JM, Doege TC, Davis RM, et al. Sleepiness, driving, and motor vehicle crashes. Council on Scientific Affairs, American Medical Association. JAMA 1998;279(23):1908-13.

Philip P, Vervialle F, Le Breton P, et al. Fatigue, alcohol, and serious road crashes in France: factorial study of national data. BMJ 2001;322(7290):829-30.

Pierce RJ. Driver sleepiness: occupational screening and the physician's role. Aust N Z J Med 1999;29(5):658-61.

Knipling RR,Wang JS. Crashes and fatalities related to driver drowsiness/fatigue. U.S. Department of Transportation. (Accessed in Feb 14, 2014, at

Carskadon MA, Dement WC. The multiple sleep latency test: what does it measure? Sleep 1982;5(Suppl 2):S67-72.

Rowley JA. Measuring the ability to stay awake: role of motivation. Sleep Breath 2006;10(4);171-2.

Mitler MM, Gujavarty KS, Browman CP. Maintenance of wakefulness test: a polysomnographic technique for evaluation treatment efficacy in patients with excessive somnolence. Electroencephalogr Clin Neurophysiol 1982;53(6):658-61.

Littner MR, Kushida C, Wise M, et al. Practice parameters for clinical use of the multiple sleep latency test and the maintenance of wakefulness test. Sleep 2005;28(1):113-21.

Banks S, Catcheside P, Lack LC, et al. The Maintenance of Wakefulness Test and driving simulator performance. Sleep 2005;28(11):1381-5.

Johns MW. A new method for measuring daytime sleepiness: the Epworth sleepiness scale. Sleep 1991;14(6):540-5.

Johns MW. Sleepiness in different situations measured bythe Epworth Sleepiness Scale Sleep 1994;17(8):703-10.

Briones B, Adams N, Strauss M, et al. Relationship between sleepiness and general health status. Sleep= 1996;19(7):583-8.

Chervin RD, Aldrich MS, Pickett R, et al. Comparison of the results of the Epworth Sleepiness Scale and the Multiple Sleep Latency Test. J Psychosom Res 1997;42(2):145-55.

Sadeghniiat Haghighi K, Montazeri A, Khajeh Mehrizi A, et al. The Epworth Sleepiness Scale: translation and validation study of the Iranian version. Sleep Breath 2013;17(1):419-26.

Arand D, Bonnet M, Hurwitz T, et al. The Clinical Use of the MSLT and MWT. Sleep 2005;28(1):123-44.

Littner MR, Kushida C, Wise M, et al. An American Academy of Sleep Medicine Report. Practice Parameters for Clinical Use of the Multiple Sleep Latency Test and the Maintenance of Wakefulness Test. Sleep 2005;28(1):113-21.

Sangal RB, Mitlerc MM, Sangal JM. Subjective sleepiness ratings (Epworth sleepiness scale) do not reflect the same parameter of sleepiness as objective sleepiness (maintenance of wakefulness test) in patients with narcolepsy. Clin Neurophysiol 1999;110(12);2131-5.

Sangal RB, Sangal JM, Belisle C. Subjective and objective indices of sleepiness (ESS and MWT) are not equally useful in patients with sleep apnea. Clin Electroencephalogr 1999;30(2):73-5.

Sagaspe P, Taillard J, Chaumet G, et al. Maintenance of wakefulness test as a predictor of driving performance in patients with untreated obstructive sleep apnea. Sleep 2007;30(3):327-30.

Moller HJ, Devins GM, Shen J, et al. Sleepiness is not the inverse of alertness: Evidence from four sleep disorder groups. Exp Brain Res 2006;173(2):258-66.

How to Cite
Sadeghniiat-Haghighi K, Moller HJ, Saraei M, Aminian O, Khajeh-Mehrizi A. The Epworth Sleepiness Scale for Screening of the Drowsy Driving: Comparison with the Maintenance of Wakefulness Test in an Iranian Sample of Commercial Drivers. Acta Med Iran. 52(2):125-129.