The role of self-motion processing in impairments of the spatial perception of auditory scenes

Natural auditory scenes typically include some motion. When this motion is the result of a moving listener, as is often the case, an accurate spatial percept requires that the listener be able to: 1) determine sound source location over time, 2) determine the extent and characteristics of his/her own motion, and 3) integrate these two pieces of information together. We assembled a battery of tests to evaluate these three criteria in normal, hearing-impaired, and balance-impaired listeners. The battery consists of a dynamic visual acuity test to estimate the listener’s self-motion processing, a measure of the minimum audible movement angle to determine source-motion acuity, and an adapted version of a previously published dynamic front/back illusion to examine the ability to combine self and sound-source motion. We found that listeners with potential vestibular impairment were more likely to have larger differences between source-motion acuity and self-motion integration acuity. This finding and the observed inter-subject variability together underscore the sensitive nature of the ongoing comparison between one’s own motion and the motion of the acoustic world. [Work supported by the MRC (Grant No. U135097131) and the Chief Scientist Office of the Scottish Government.]