Effects of Different Alcohol Dosages and Display Illumination on Tracking Performance during Vestibular Stimulation,

: A previous investigation showed that alcohol impairs the ability to suppress vestibular nystagmus, thus degrading visual compensatory tracking performance during angular acceleration. Reduced display illumination, independently, has also been shown to degrade tracking performance during vestibular stimulation. The present study investigated the way in which low and moderate dosages of alcohol and two levels of instrument-display illumination combined to affect tracking performance a) in a static (no motion) environment, and b) in a dynamic (whole-body motion) environment. Mean blood-alcohol levels as low as 0.027 per cent significantly (p<.05) decreased tracking performance during whole-body motion, yet caused little change in performance in a stationary environment. Impairment was much more pronounced with dim display lighting (0.1 ft-L) than with bright lighting (1.0 ft-L). These results suggest that serious problems may even be encountered by the pilot who drinks lightly and who considers flying, expecially at night. (Author)