0299 Total Sleep Deprivation and Time on Task: Not the Same for Sustained Attention and Executive Processes and Poor Benefit of Caffeine

Abstract Introduction Mental Fatigue is commonly questioned regarding time on task or sleep debt effect (Hockey, 2013; Pattyn et al., 2018) or sleep debt effect (Krause et al., 2017). No studies have neither investigated contributions of these two factors for different cognitive processes nor benefit of caffeine. Methods 24 right-handed and healthy subjects (18–50 years old), with a median chronotype and sleep need participated in a 2-experimental counter-balanced (placebo: PBO and caffeine: COFFEE - 2.5 mg/kg) total sleep deprivation protocol (TSD = 27 hours of continuous wakefulness). Subjective sleepiness (KSS), sustained attention (PC-PVT), inhibition (Go-NoGo) and working memory (2N-Back) capabilities were tested each morning during BASE and TSD (10 min. test session from 9:15 am to 10:15 am). Caffeine was ingested with a decaffeinated drink at 8:30 am. Results KSS score (5.6±0.4 vs 3.2±0.3; p