Frequency mismatch and spectral integration in acoustic and electric hearing

摘要：双侧人工耳蜗(CI)患者和单侧耳聋(SSD)CI患者必须 整合不同耳朵之间可能完全不同的光谱模式。由于声波之间的相互作用- 电频率分配和电极阵列的有限范围/插入深度，CI患者可能 耳内声音输入频率与耳内电极位置不匹配 植入的耳朵。双侧和SSD CI患者也可能经历耳间不匹配 每个音频中的频率位置分配，这可能限制语音和本地化的双耳优势。放射学 成像可以估计耳蜗内电极的位置，但不能表征电极-神经。 界面(健康神经元对电极的接近程度)，这是频率的最终仲裁者 不匹配。单声道耳间基音匹配可能不能完全表征失配的影响 多通道语音感知。在给定其加性属性的情况下，使用频带受限的非冗余语音 (而不是宽带语音)可以更深入地了解频率失配对 光谱积分。可以估计用于非冗余语音的最佳带宽和频率范围 来自频率重要性函数。 这项建议的长期目标是更好地了解频率失配如何影响频谱 耳朵内和耳朵之间的整合。假设频率重要性函数可能相当于 CI和正常听力(NH)听者之间存在差异，并且可能受到频率失配的影响。它是 还假设频率失配对频谱积分的影响可以在 使用有限频带、非冗余语音的噪声。最后，提出了两种不同类型的人耳间距离的假设 使用互补的、非冗余的方法可以准确、高效地估计CI患者的不匹配 呈现给每只耳朵的语音信息。提出了三个目标，以更好地探索光谱 积分受到频率失配的影响。目标1将探索频率失配如何影响 语音清晰度的频率重要性函数。目标2将探索频率失配如何影响 听单侧、双侧和SSD CI的NH受试者耳朵内和跨耳的频谱整合 模拟，并进一步评估一种新的技术来估计耳间失配， 为每只耳朵提供互补的、频带受限的、无冗余的语音提示。《目标3》将使用上述小说 在真实CI患者中估计耳间失配并进一步优化频率分配的技术 以减少耳间的失配。拟议的研究具有很大的理论意义，因为它将为 对限制双侧和SSD脑梗塞患者双耳整合的因素有更深入的了解。建议数 研究也具有很大的临床价值，因为研究结果可能为准确和 高效优化CI频率分配，最大限度地提高双边和SSD CI用户的双耳收益。

SUMMARY: Bilateral cochlear implant (CI) patients and CI patients with single-sided deafness (SSD) must integrate spectral patterns that might be quite different across ears. Due to interactions between the acoustic- to-electric frequency allocation and the limited extent/insertion depth of the electrode array, CI patients may experience an intra-aural mismatch between the acoustic input frequency and the electrode place within an implanted ear. Bilateral and SSD CI patients may also experience inter-aural mismatch between the frequency-place allocation in each, which may limit binaural benefits for speech and localization. Radiological imaging can estimate electrode positions within the cochlea, but cannot characterize the electrode-neural interface (the proximity of healthy neurons to the electrode), which is the ultimate arbiter of frequency mismatch. Single-channel inter-aural pitch-matching may not fully characterize the effects of mismatch for multi-channel speech perception. Given its additive properties, using band-limited, non-redundant speech (rather than broadband speech) may provide greater insight regarding the effects of frequency mismatch on spectral integration. Optimal bandwidths and frequency ranges for non-redundant speech may be estimated from frequency importance functions. The long-term goal of this proposal is to better understand how frequency mismatch affects spectral integration within and across ears. It is hypothesized that frequency importance functions may be quite different between CI and normal-hearing (NH) listeners, and may be affected by frequency mismatch. It is also hypothesized that the effects of frequency mismatch on spectral integration can be better estimated in noise using band-limited, non-redundant speech. Finally, it is hypothesized that the degree of inter-aural mismatch in CI patients can be accurately and efficiently estimated using complementary, non-redundant speech information presented to each ear. Three aims are proposed to better explore how spectral integration is affected by frequency mismatch. Aim 1 will explore how frequency mismatch affects the frequency importance function for speech intelligibility. Aim 2 will explore how frequency mismatch affects spectral integration within and across ears in NH subjects listening to unilateral, bilateral, and SSD CI simulations, and further evaluate a novel technique to estimate inter-aural mismatch by delivering, complementary, band-limited, non-redundant speech cues to each ear. Aim 3 will use the above novel technique to estimate inter-aural mismatch in real CI patients and further optimize the frequency allocation to reduce inter-aural mismatch. The proposed research is of great theoretical interest, as it will provide greater insights into factors that limit binaural integration in bilateral and SSD CI patients. The proposed research is also of great clinical value, as the results may provide useful clinical tools to accurately and efficiently optimize CI frequency allocations to maximize binaural benefits for bilateral and SSD CI users.