Fischer Tim, Schmid Christoph, Kompis Martin, Mantokoudis Georgios, Caversaccio Marco, Wimmer Wilhelm
Department of ENT, Head and Neck Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
Hearing Research Laboratory, ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland.
Ear Hear. 2021 Jan/Feb;42(1):214-222. doi: 10.1097/AUD.0000000000000912.
To compare the sound-source localization, discrimination, and tracking performance of bilateral cochlear implant users with omnidirectional (OMNI) and pinna-imitating (PI) microphone directionality modes.
Twelve experienced bilateral cochlear implant users participated in the study. Their audio processors were fitted with two different programs featuring either the OMNI or PI mode. Each subject performed static and dynamic sound field spatial hearing tests in the horizontal plane. The static tests consisted of an absolute sound localization test and a minimum audible angle test, which was measured at eight azimuth directions. Dynamic sound tracking ability was evaluated by the subject correctly indicating the direction of a moving stimulus along two circular paths around the subject.
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 straight to the sides (90° and 270° angle) was only possible with PI mode. The averaged minimum audible angle value for the 90° and 270° angle positions decreased from a 75.5° to a 37.7° angle when PI mode was used (p < 0.001). Furthermore, a non-significant trend towards an improvement in the ability to track moving sound sources was observed for both trajectories tested (p = 0.34 and p = 0.27).
Our results demonstrate that PI mode can lead to improved spatial hearing performance in bilateral cochlear implant users, mainly as a consequence of improved front-back discrimination with PI mode.
比较双侧人工耳蜗使用者在全向性（OMNI）和模仿耳廓（PI）麦克风指向性模式下的声源定位、辨别和跟踪性能。
12名有经验的双侧人工耳蜗使用者参与了这项研究。他们的音频处理器安装了两种不同的程序，分别具有OMNI或PI模式。每个受试者在水平面进行静态和动态声场空间听力测试。静态测试包括绝对声源定位测试和最小可听角测试，在八个方位角方向进行测量。动态声音跟踪能力通过受试者正确指示沿其周围两条圆形路径移动的刺激源方向来评估。
PI模式在声源定位和辨别方面有统计学意义的改善。对于静态声源定位，最大的益处是减少了前后混淆的次数。前后混淆率从OMNI模式的47%降至PI模式的35%（p = 0.03）。只有使用PI模式才能辨别直接在两侧（90°和270°角）的声源。使用PI模式时，90°和270°角位置的平均最小可听角值从75.5°降至37.7°（p < 0.001）。此外，在测试的两条轨迹上，观察到跟踪移动声源能力有改善的非显著趋势（p = 0.34和p = 0.27）。
我们的结果表明，PI模式可改善双侧人工耳蜗使用者的空间听力性能，主要是因为PI模式改善了前后辨别能力。
