Sound lateralization during passive whole-body rotation.

The effect of passive whole-body rotation about the earth-vertical axis on the lateralization of dichotic sound was investigated in human subjects. Pure-tone pulses (1 kHz; 0.1 s duration) with various interaural time differences were presented via headphones during brief, low-amplitude rotation (angular acceleration 400 degrees/s2; maximum velocity 90 degrees/s; maximum displacement 194 degrees ). Subjects made two-alternative forced-choice (left/right) judgements on the acoustic stimuli. The auditory median plane of the head was shifted opposite to the direction of rotation, indicating a shift of the intracranial auditory percept in the direction of rotation. The mean magnitude of the shift was 10.7 micros. This result demonstrates a slight, but significant, influence of rotation on sound lateralization, suggesting that vestibular information is taken into account by the brain for accurate localization of stationary sound sources during natural head and body motion.