Introduction: The medial olivocochlear reflex (MOCR) is a part of the binaural processing strategies and influences the efferent auditory pathway in normal-hearing individuals. Patients with asymmetric hearing loss often benefit from a bimodal hearing solution with a cochlear implant (CI) and a hearing aid (HA). However, hearing performances may vary with some surprisingly high- or low-performing CI/HA users. A potential role of the MOCR among these patients warrants further investigation. Otoacustics emissions are an established method to visualize the reflex; however, this technique implies some disadvantages. To visualize the MOCR via auditory brainstem response (ABR) could be a promising alternative. Methods: Twenty-three bimodal CI/HA users were enrolled. Experimental setup was as follows: I. electrical ABR on the CI side was recorded with and without simultaneous contralateral noise signal at the HA side, II. acoustic ABR was recorded on the HA side with and without simultaneous contralateral noise at the CI side. Brainstem thresholds and amplitudes of waveforms I–V with and without contralateral noise were compared. Potential correlations of patient-related factors and hearing performances were analysed. Results: In four individuals, a reduction of brainstem audiometry thresholds could be observed at the acoustic brainstem audiometry. In these cases, results could be reproduced. Summarizing ABR measurements at the HA side of all individuals, no relevant changes of ABR thresholds (dB nHL) or waveform amplitude reductions (nV) could be observed irrespective of the presence or absence of a contralateral suppression signal. Conclusion: Threshold changes of acoustic ABR upon presentation of a contralateral suppression signal could not generally be measured in bimodal CI users. However, in a subgroup, a highly reproducible effect was demonstrated if a contralateral suppression signal was applied. A reactivated rather than rehabilitated MOCR may have accounted for this effect in this subgroup. One could speculate that in these patients, bimodal fitting could be affected by the MOCR efferents.
Audiol Neurotol

中文翻译：

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通过双峰人工耳蜗植入患者的声学和电脑干测听法可视化对侧听力敏感性抑制：一项可行性研究

简介：内侧橄榄耳蜗反射 (MOCR) 是双耳处理策略的一部分，会影响正常听力者的传出听觉通路。不对称性听力损失患者通常受益于人工耳蜗 (CI) 和助听器 (HA) 的双模式听力解决方案。然而，听力表现可能会因一些令人惊讶的高或低表现 CI/HA 用户而异。MOCR 在这些患者中的潜在作用值得进一步研究。耳声发射是可视化反射的既定方法；然而，这种技术意味着一些缺点。通过听觉脑干反应 (ABR) 可视化 MOCR 可能是一个很有前途的选择。方法：登记了 23 名双峰 CI/HA 用户。实验设置如下：I. 记录 CI 侧的电 ABR，同时在 HA 侧记录和不记录对侧噪声信号，II。声学 ABR 在 HA 侧记录，在 CI 侧有和没有同时对侧噪声。比较了有和没有对侧噪声的脑干阈值和波形 I-V 的振幅。分析了患者相关因素与听力表现的潜在相关性。结果：在四个人中，可以在声学脑干测听中观察到脑干测听阈值的降低。在这些情况下，结果可以重现。总结所有个体 HA 侧的 ABR 测量值，无论是否存在对侧抑制信号，都无法观察到 ABR 阈值 (dB nHL) 或波形幅度降低 (nV) 的相关变化。结论：双峰 CI 用户通常无法测量在呈现对侧抑制信号时声学 ABR 的阈值变化。然而，在一个子组中，如果应用对侧抑制信号，则证明了高度可重复的效果。重新激活而非恢复的 MOCR 可能是该亚组中这种影响的原因。人们可以推测，在这些患者中，双峰拟合可能会受到 MOCR 传出神经的影响。
听觉神经醇