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Subjective sleepiness, simulated driving performance and blink duration: examining individual differences
Author(s) -
INGRE MICHAEL,
ÅKERSTEDT TORBJÖRN,
PETERS BJÖRN,
ANUND ANNA,
KECKLUND GÖRAN
Publication year - 2006
Publication title -
journal of sleep research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 117
eISSN - 1365-2869
pISSN - 0962-1105
DOI - 10.1111/j.1365-2869.2006.00504.x
Subject(s) - audiology , driving simulator , psychology , analysis of variance , alertness , simulation , driving simulation , medicine , statistics , mathematics , engineering , psychiatry
Summary The present study aimed to provide subject‐specific estimates of the relation between subjective sleepiness measured with the Karolinska Sleepiness Scale (KSS) and blink duration (BLINKD) and lane drifting calculated as the standard deviation of the lateral position (SDLAT) in a high‐fidelity moving base driving simulator. Five male and five female shift workers were recruited to participate in a 2‐h drive (08:00–10:00 hours) after a normal night sleep and after working a night shift. Subjective sleepiness was rated on the KSS in 5‐min intervals during the drive, electro‐occulogram (EOG) was measured continuously to calculate BLINKD, and SDLAT was collected from the simulator. A mixed model anova showed a significant ( P < 0.001) effect of the KSS for both dependent variables. A test for a quadratic trend suggests a curvilinear effect with a steeper increase at high KSS levels for both SDLAT ( P < 0.001) and BLINKD ( P = 0.003). Large individual differences were observed for the intercept ( P < 0.001), suggesting that subjects differed in their overall driving performance and blink duration independent of sleepiness levels. The results have implications for any application that needs prediction at the subject level (e.g. driver fatigue warning systems) as well as for research design and the interpretation of group average data.