Reaction of sleepiness indicators to partial sleep deprivation, time of day and time on task in a driving simulator - the DROWSI project

Abstract

SUMMARY Studies of driving and sleepiness indicators have mainly focused on prior sleep reduction. The present study sought to identify sleepiness indicators responsive to several potential regulators of sleepiness: sleep loss, time of day (TOD) and time on task (TOT) during simulator driving. Thirteen subjects drove a high-fidelity moving base simulator in six 1-h sessions across a 24-h period, after normal sleep duration (8 h) and after partial sleep deprivation (PSD; 4 h). The results showed clear main effects of TOD (night) and TOT but not for PSD, although the latter strongly interacted with TOD. The most sensitive variable was subjective sleepiness, the standard deviation of lateral position (SDLAT) and measures of eye closure [duration, speed (slow), amplitude (low)]. Measures of electroencephalography and line crossings (LCs) showed only modest responses. For most variables individual differences vastly exceeded those of the fixed effects, except for subjective sleepiness and SDLAT. In a multiple regression analysis, SDLAT, amplitude ⁄ peak eye-lid closing velocity and blink duration predicted subjective sleepiness bouts with a sensitivity and specificity of about 70%, but were mutually redundant. The prediction of LCs gave considerably weaker, but similar results. In summary, SDLAT and eye closure variables could be candidates for use in sleepiness-monitoring devices. However, individual differences are considerable and there is need for research on how to identify and predict individual differences in susceptibility to sleepiness.k e y w o r d s accidents,

Short Sleep Duration, Snoring and Subjective Sleep Insufficiency Are Independent Factors Associated with both Falling Asleep and Feeling Sleepiness while Driving

“…Nevertheless, the present study revealed that, for the studied drivers, falling asleep and feeling sleepiness while driving were associated with both loud snoring or apnea and short sleep duration, similar to results found in Western countries (1)(2)(3)(4)(5)9). Feeling subjective sleepiness while driving is coincident with deteriorated performance in driving simulator tasks and real driving situations (26)(27)(28). Moreover, the existence of subjective sleepiness clearly raises the risk of MVCs (6-8, 12).…”

The severity of driver fatigue in terms of line crossing: a pilot study comparing day- and night time driving in simulator

“…KSS increased with time on task and blink duration was longer with time on task, this is in line with earlier research [34,35]. Our results indicate that future development and improvements of driver support systems may use different criteria's or thresholds for activations of warnings day time compare to night time if the aim is to avoid critical situations.…”

Ocular Measures of Sleepiness Are Increased in Night Shift Workers Undergoing a Simulated Night Shift Near the Peak Time of the 6-Sulfatoxymelatonin Rhythm

“…However, none of the participants in our study required prescription lenses. The system provides 13 ocular measures sampled each minute, of which the following were selected based on previous work [21][22][23][24][25][26][27] (detailed description of each measure provided in Table 1): positive and negative amplitude/velocity ratio of each blink (PosAVR, NegAVR), Johns Drowsiness Scale (JDS) score, the percentage of time with eyes closed (%TEC), and mean blink total durations (BTD). For all measures, higher values indicate higher levels of sleepiness.…”