Department for Hearing, Speech and Voice Disorders.
Department of Otorhinolaryngology, Medical University Innsbruck, Innsbruck, Austria.
Otol Neurotol. 2024 Mar 1;45(3):e228-e233. doi: 10.1097/MAO.0000000000004090. Epub 2024 Jan 10.
The ability to localize sounds is partly recovered in patients using a cochlear implant (CI) in one ear and a hearing aid (HA) on the contralateral side. Binaural processing seems effective at least to some extent, despite the difference between electric and acoustic stimulation in each ear. To obtain further insights into the mechanisms of binaural hearing in these listeners, localization of low- and high-frequency sounds was tested.
The study used a within-subject design, where participants were tasked with localizing sound sources in the horizontal plane. The experiment was conducted in an anechoic chamber, where an array of seven loudspeakers was mounted along the 24 azimuthal angle span from -90° to +90°. Stimuli were applied with different frequencies: broadband noise and high- and low-frequency noise.
Ten CI recipients participated in the study. All had an asymmetric hearing loss with a CI in the poorer ear and an HA on the contralateral side.
Accuracy of sound localization in terms of angular error and percentage of correct localization scores.
The median angular error was 40° in bimodal conditions for both broadband noise and high-frequency noise stimuli. The angular error increased to 47° for low-frequency noise stimuli. In the unilaterally aided condition with an HA, only a median angular error of 78° was observed.
Irrespective of the frequency composition of the stimuli, this group of bimodal listeners showed some ability to localize sounds. Angular errors were larger than those reported in the literature for bilateral CI users or single-sided deaf listeners with a CI. In the unilateral listening condition with HA, only localization of sounds was not possible for most subjects.
在一侧耳朵使用人工耳蜗（CI），另一侧耳朵使用助听器（HA）的患者，其定位声音的能力部分得到了恢复。尽管每只耳朵的电刺激和声学刺激存在差异，但双耳处理似乎至少在某种程度上是有效的。为了更深入地了解这些患者的双耳听力机制，测试了低频和高频声音的定位情况。
本研究采用了一种被试内设计，要求参与者在水平面上定位声源。实验在消声室内进行，七个扬声器组成的阵列安装在从-90°到+90°的 24 个方位角跨度内。刺激采用不同频率：宽带噪声和高低频噪声。
十名 CI 接受者参与了这项研究。所有受试者均有不对称性听力损失，较差耳侧植入 CI，对侧佩戴 HA。
以角度误差和正确定位分数的百分比来衡量声音定位的准确性。
在宽带噪声和高频噪声刺激的双模条件下，中位数角度误差为 40°。低频噪声刺激的角度误差增加到 47°。在仅使用 HA 的单侧辅助条件下，仅观察到中位数角度误差为 78°。
无论刺激的频率组成如何，这组双模聆听者都表现出一定的声音定位能力。角度误差大于文献中报道的双侧 CI 用户或单侧 CI 单侧聋患者的角度误差。在使用 HA 的单侧聆听条件下，大多数受试者几乎无法定位声音。
