Sound Localization and Discrimination in Bilateral Cochlear Implant Users with Pinna-Imitating Microphone Directionality
* Presenting author
Abstract:
We compared the sound-source localization, discrimination, and tracking performance of 12 bilateral cochlear implant users with omnidirectional (OMNI) and pinna-imitating (PI) microphone directionality modes.Each subject performed static and dynamic sound field tests in the horizontal plane. The static tests consisted of an absolute sound localization test and a minimum audible angle (MAA) test measured at eight azimuth directions. Dynamic sound-tracking was evaluated by the subjects indicating the direction of a moving stimulus along two circular paths.The PI mode led to statistically significant sound localization and discrimination improvements. For static sound localization, the greatest benefit was a reduction in the number of front-back confusions. The front-back confusion rate was reduced from 47% with OMNI mode to 35% with PI mode (p = 0.03). The ability to discriminate sound sources to the sides (90°&270°) was only possible with PI mode. The averaged MAA for 90° and 270° decreased from 75.5° to 37.7° with the PI mode (p<0.001). A non-significant trend towards improving the ability to track moving sound sources was observed.Our results demonstrate that PI mode improves spatial hearing performance in bilateral CI users, mainly due to improved front-back discrimination.