The medico-legal assessment of driving performance, particularly of professional drivers or pilots, after the occurrence of vestibular disease requires more objective criteria than have been employed. The purpose of the present study was to examine the direct influence of vestibular disorder on vehicle driving performance in the safety of an automobile simulator facility. The subjects' performance, as reflected by driving speed, steering behaviour, and lane position, was compared for conditions with normal vestibular function and with induced vestibular imbalance. It was observed that driving speed was reduced during all trials with induced vestibular imbalance. In addition, during trials with induced vestibular imbalance, the test subjects drove more closely to the centre line of the road. The event-triggered evaluation of steering behaviour (i.e. contingent on occurrence of nystagmus) demonstrated a systematic interaction between involuntary eye movements and corrections to steering position.
Abstract