Incidence of positive Epworth Sleepiness Scale Test in aviation pilots

Today more than two thirds of aircraft accidents are directly related to human factors. The concept of human factor includes several components of which the ability, psychophysical and physiological conditions of the pilots represent the most important ones. Although the number of general aviation accidents has dramatically decreased over the past two decades the percentage of flying incidents due to human factor has remained unchanged. Obstructive Sleep Apnoea Syndrome (OSAS) affects approximately 5-15 % of the population. It typically affects cognitive functions as a result of sleep fragmentation and reduced oxygen saturation. Disturbed sleep related to rapid and large time zone changes and the variability of sleeping time and duration are all well known contributing elements to the impairment of the alertness level experienced by pilots. These alterations of the sleep-wakefulness status might worsen or reveal the effects of underlying pathologies such as OSAS. Excessive daytime sleepiness (EDS) has not been systematically evaluated amongst pilots. In this study we assessed the EDS of 398 military and civil aviation pilots using the Epworth Sleepiness Scale (ESS), a questionnaire employed by the majority of the sleep centres to estimate the presence of obstructive sleep apnoea. Our results suggest that 8.9 % of aircraft pilots are likely to suffer from obstructive sleep apnoea. In light of this we believe that the ESS, a simple and inexpensive screening questionnaire for EDS, should be employed to select pilots that will require an objective polysomnographic (PSG) evaluation of OSAS.