Improved Speech Perception for Bimodal Implants (Fowler et al., 2016)

Purpose: The objective was to determine whether speech perception could be improved for bimodal listeners (those using a cochlear implant [CI] in one ear and hearing aid in the contralateral ear) by removing low-frequency information provided by the CI, thereby reducing acoustic–electric overlap.Method: Subjects were adult CI subjects with at least 1 year of CI experience. Nine subjects were evaluated in the CI-only condition (control condition), and 26 subjects were evaluated in the bimodal condition. CIs were programmed with 4 experimental programs in which the low cutoff frequency (LCF) was progressively raised. Speech perception was evaluated using Consonant-Nucleus-Consonant words in quiet, AzBio sentences in background babble, and spondee words in background babble.Results: The CI-only group showed decreased speech perception in both quiet and noise as the LCF was raised. Bimodal subjects with better hearing in the hearing aid ear (< 60 dB HL at 250 and 500 Hz) performed best for words in quiet as the LCF was raised. In contrast, bimodal subjects with worse hearing (> 60 dB HL at 250 and 500 Hz) performed similarly to the CI-only group.Conclusions: These findings suggest that reducing low-frequency overlap of the CI and contralateral hearing aid may improve performance in quiet for some bimodal listeners with better hearing.

研究目的：本研究的目的是探讨通过移除耳蜗植入器（CI）提供的低频信息，从而减少耳蜗植入器与对侧助听器之间的声电重叠，是否能够提升双模态听者（即在一侧耳朵使用耳蜗植入器，在对侧耳朵使用助听器）的语音感知能力。研究方法：受试者均为具有至少1年耳蜗植入器使用经验的成人。在仅使用耳蜗植入器的条件下（对照组），评估了9名受试者；在双模态条件下，评估了26名受试者。耳蜗植入器被编程为四种实验程序，其中低截止频率（LCF）逐渐提高。语音感知能力通过在安静环境中的辅音-元音-辅音单词、背景嘈杂声中的AzBio句子以及在背景嘈杂声中的双元音单词进行评估。研究结果：随着LCF的提高，仅使用耳蜗植入器的组在安静和噪声环境中的语音感知能力均有所下降。在助听器侧听力较好（250Hz和500Hz频率下的听力水平低于60 dB HL）的双模态受试者在LCF提高时对安静环境中的单词表现最佳。相反，在助听器侧听力较差（250Hz和500Hz频率下的听力水平高于60 dB HL）的双模态受试者与仅使用耳蜗植入器的组表现相似。研究结论：这些发现表明，减少耳蜗植入器与对侧助听器之间的低频重叠，可能有助于提升某些听力较好的双模态听者在安静环境中的表现。