Fatigue management: The art of the state

Introductio The aim of this volume is to provide a review, synthesis, and analysis of the literature pertaining to stimulant medications and cognitive performance. As indicated in Chapters 5–8 (this volume), stimulants such as caffeine and modafinil maintain cognitive performance during sleep loss and thereby play a role in managing cognitive performance under a variety of operational conditions such as those described in Chapter 17. In this final chapter, we provide a brief overview of current hours of service rules and guidelines for several industries (airline, railroad, trucking – see also Chapter 15, this volume, for a detailed review of fatigue management hardware tools). We then describe cognitive effectiveness prediction model components and provide examples of their use. Finally, we describe how output from such models can be used to make informed decisions regarding stimulant use. Fatigue: a definition Although “fatigue” is a recognized threat to safety in most commercial and military operational settings, what exactly constitutes “fatigue” is a matter of ongoing debate. The International Civil Aviation Organization (ICAO) Fatigue Risk Management Systems Task Force (FRMS TF) describes fatigue as being associated with performance declines including decreased vigilance, increasingly variable but overall slower reaction times, forgetfulness, inattention, poor decision-making, apathy, mood swings, diminished communication, and finally frank sleep onset [1]. They list causes of fatigue as task-related factors, circadian factors, and sleep-related factors [1]. In keeping with the ICAO FRMS TF framework (and the theme of this book), throughout this chapter we use the term “fatigue” to mean objectively measured cognitive performance degradation caused by sleep loss and time of day – the two measurable factors exerting the greatest impact on cognitive performance.