Abstract
We examined the effects of powerful sound stimuli on postural stability in normal humans. Sound stimuli consisted of pure tone of 500 Hz, 105 dB HL for 5 sec duration, which were applied to the right ear. Each subject was studied under 4 different conditions: eyes open, eyes closed, head rotated 90 degree to the right and head rotated 90 degree to the left. Positive responses were observed in more than 85% of the subjects. Preponderance of response direction was indefinite under most conditions in subjects. Mono-phase postural responses were most elicited, but poly-phase responses were frequently observed in this experiment. In order to prove the vestibular-evoked responses, postural responses of patients with absent vestibular function and deaf patients have to be examined. Reproducibility and habituation of responses also will be examined in a future experiment.
