Frequency mismatch and spectral integration in acoustic and electric hearing

总结：双侧人工耳蜗植入（CI）患者和单侧耳聋（SSD）CI患者必须 整合了不同耳朵的光谱模式。由于声学之间的相互作用- 由于电极阵列的电频率分配和有限的范围/插入深度，CI患者可能 经历声输入频率和电极位置之间的耳内失配， 植入耳双侧和SSD CI患者也可能会出现耳间不匹配， 频率位置分配，这可能限制语音和定位的双耳益处。放射 成像可以估计耳蜗内的电极位置，但不能表征电极-神经 接口（健康神经元与电极的接近程度），这是频率的最终仲裁者 不匹配.单声道耳间音高匹配可能无法完全表征失配的影响， 多通道语音感知考虑到它的附加特性，使用带限的非冗余语音 （而不是宽带语音）可以提供关于频率失配对 谱积分可以估计非冗余语音的最佳带宽和频率范围 频率重要性函数。 该提案的长期目标是更好地了解频率失配如何影响频谱 耳内和耳间的整合。假设频率重要性函数可能相当 CI和正常听力（NH）听众之间的差异，并且可能受到频率失配的影响。是 还假设频率失配对频谱积分的影响可以更好地估计， 噪声使用带限，非冗余语音。最后，假设耳间 CI患者的不匹配可以使用互补的、非冗余的 语音信息呈现给每只耳朵。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将探讨频率失配如何影响 语音清晰度的频率重要性函数。目标2将探讨频率失配如何影响 NH受试者听单侧、双侧和SSD CI时耳内和耳间的频谱整合 模拟，并进一步评估一种新的技术，以估计耳间失配通过交付， 互补的、带限的、非冗余的语音提示。Aim 3将使用上述小说 估计真实的CI患者的耳间失配并进一步优化频率分配的技术 以减少耳间失配。这项研究具有很大的理论意义，因为它将提供 更深入地了解限制双侧和SSD CI患者双耳整合的因素。拟议 研究也具有很大的临床价值，因为研究结果可以提供有用的临床工具， 有效地优化CI频率分配，以最大限度地提高双耳的好处，为双边和SSD CI用户。

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.