ABSTRACT
This chapter examines measures of the related issue of sleepiness. It focuses on non-pathological fatigue in otherwise healthy individuals. Non-pathological fatigue is usually a short-lived phenomenon of exertion or sleep deprivation, which is reduced if not eliminated by rest or sleep. Most scales include items that assess the feelings of fatigue and the perceived impact of fatigue on the lives of respondents. In addition to directly asking about feelings of fatigue, most scales also ask respondents to report on the impact of fatigue on the daily activities. The chapter reviews the approaches to the measurement of fatigue. Fatigue can be seen as either a "subjective feeling" or a "performance decrement". Performance-based measures of fatigue represent the other major approach to assessment. Self-report scales provide no such external verification, but they are unique in assessing the individual's experience and feelings of fatigue. Correlations have been found between blink measures and self-reported fatigue in fighter pilots.
