Hearing impairment, hearing aids, and cues for self motion

When listeners make a head rotation, they compare the speed and direction of a signal with the speed and direction of their movement. Hearing impairment is frequently co-morbid with vestibular impairment, rendering access to self-motion cues less reliable. It is associated with an increase in the minimum audible movement angle, and is also typically associated with raised thresholds in the range of frequencies in which the filtering effects of the pinna are most spatially useful for resolving front/back localization ambiguities for example. Moving a sound source as a function of the position of the listener’s head creates a front/back illusion. This illusion has been used to demonstrate that listeners with hearing impairment rely more on self-motion cues than on high frequency information. The use of hearing aids had heterogeneous effects on the task, although in no case did they return a listener to normal performance. Recordings were made of the output of hearing aids driven with a noise sequence whose ...