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An English language self-assessment Morningness-Eveningness questionnaire is presented and evaluated against individual differences in the circadian vatiation of oral temperature. 48 subjects falling into Morning, Evening and Intermediate type categories regularly took their temperature. Circadian peak time were identified from the smoothed temperature(More)
Few sleep deprivation (SD) studies involve realism or high-level decision making, factors relevant to managers, military commanders, and so forth, who are undergoing prolonged work during crises. Instead, research has favored simple tasks sensitive to SD mostly because of their dull monotony. In contrast, complex rule-based, convergent, and logical tasks(More)
Neuropsychological testing and brain imaging show that healthy aging leads to a preferential impairment of the prefrontal cortex (PFC). Interestingly, in young adults sleep deprivation (SD) has similar effects. Psychological tasks not so oriented to the PFC are less sensitive both to SD and aging. The PFC is a cortical region working particularly hard(More)
OBJECTIVES To assess the incidence, time of day, and driver morbidity associated with vehicle accidents where the most likely cause was the driver falling asleep at the wheel. DESIGN Two surveys were undertaken, in southwest England and the midlands, by using police databases or on the spot interviews. SUBJECTS Drivers involved in 679 sleep related(More)
Driver sleepiness is a major cause of serious road crashes. Coffee is often used as an effective countermeasure to driver sleepiness. However, the caffeine levels in coffee are variable, whereas certain proprietary "functional energy drinks" (FEDs) contain known levels of caffeine (and other ingredients). We investigated the effectiveness of a well-known(More)
Historical evidence suggests that sleep deprivation affects temporal memory, but this has not been studied systematically. We explored the effects of 36 hr of sleep deprivation on a neuropsychological test of temporal memory. To promote optimal performance, the test was short, novel, and interesting, and caffeine was used to reduce "sleepiness". A total of(More)
Although much is known about the impact of sleep loss on many aspects of psychological performance, the effects on divergent ("creative") thinking has received little attention. Twelve subjects went 32 h without sleep, and 12 others acted as normally sleeping controls. All subjects were assessed on the figural and verbal versions of the Torrance Tests of(More)
Recent findings with clinically oriented neuropsychological tests suggest that one night without sleep causes particular impairment to tasks requiring flexible thinking and the updating of plans in the light of new information. This relatively little investigated field of sleep deprivation research has real-world implications for decision makers having lost(More)
Sleepy drivers should "take a break," but the efficacy of feasible additional countermeasures that can be used during the break is unknown. We examined a shorter than 15 min nap, 150 mg of caffeine in coffee, and a coffee placebo, each given randomly across test sessions to 10 sleepy subjects during a 30-min rest period between two 1-hr monotonous early(More)
500 ml of a glucose based "energy" drink versus a control without the active ingredients (caffeine, taurine, glucuronolactone) were given double blind to 11 sleepy participants driving an interactive real-car driving simulator. Lane drifting and a secondary task (reaction time) were measured for two hours post-treatment. The energy drink significantly(More)