Comparative sensitivity of outcome variables of a software-based Behavioral Sleep Resistance Task

Abstract

Unintentional sleep and performance impairment due to extended wakefulness are often the cause of traffic and work accidents. Therefore, large-scale screening instruments assessing the ability to resist falling asleep during monotonous tasks are needed. The current wide-spread computer use in industrial and home settings offers the possibility to use software-based instruments as an alternative for expensive hardware interfaces to assess sleep resistance. Therefore, we propose a software-based sleep resistance task based on the procedure of the Oxford SLEep Resistance test (OSLER): the Behavioral Sleep Resistance Task (BSRT). In order to validate this instrument we submitted 36 healthy individuals to four 40-min sleep resistance challenges during a night of extended wakefulness (14, 16, 18 and 20 h). Subjective sleepiness was assessed by means of the Karolinska Sleepiness Scale and a Visual Analogue Scale for sleepiness/alertness and objective sleepiness by means of a 4-min EEG-monitored fixation task. Our results show significant correlations of BSRT bit ratio, error profiles and sleep onset latency variables with subjective sleepiness and of BSRT hit ratio and 3-6 error profiles with High-Beta Central EEG activity. Additionally, using a distribution- and scale-free sensitivity index, we found that subjective sleepiness measures are the most sensitive to the effects of sustained wakefulness, closely followed by the BSRT hit ratio and BSRT error profile 3-6.