Reduction in spread of excitation as predictor multi-channel spectral resolution

描述（由申请人提供）：耳蜗植入物（CI）为大多数聋人提供了良好的功能性听力，但在噪音或音乐等复杂声音中听力的益处有限。为了提高人工耳蜗的性能，我们需要识别这些困难听力情况下最重要的线索，并找到通过植入物呈现这些线索的方法。改善光谱选择性应改善植入物性能，但受到物理、生物和感知因素的限制。对于单个植入收听器，频谱选择性可能受到不良电极放置和/或不良神经存活的限制。新技术（电流聚焦）已被研究，以减少电流扩散，从而提高光谱选择性。然而，来自我们实验室的数据表明，电流聚焦仅减少了约一半受试患者的兴奋扩散（SOE）。只有当SOE实际减少时，才能期望当前重点的性能改进。在拟议的实验中，我们将提供噪声和音乐任务（具体目标3）中语音变化的第一个受试者内测量值，因为它们与多通道频谱模式识别（具体目标2）的变化和单通道SOE（具体目标1）的减少有关。我们预计，目前的重点可以导致国有企业的减少，这反过来将 在噪音和音乐表现中产生言语改善。然而，由于局部神经存活、电极放置和可变局部阻抗，我们预计仅在一部分患者中可实现SOE的降低。因此，我们还将研究预测哪些患者将从电流聚焦中受益的快速（和临床相关）方法（实验2和3）。本研究的总体目标是确定是否可以通过电流聚焦改善某些患者的功能光谱分辨率，并确定在临床相关程序中哪些患者将受益于电流聚焦。我们假设，如果电流聚焦可以减少激发的传播，那么频谱分辨率将增加，并在具有挑战性的收听条件下改善CI性能（例如，噪声中的语音、音乐）。这项研究的目的是：（a）评估SOE变化、多通道辨别力与语音和音乐任务成绩之间的关系，（B）提高CI听力者的成绩。这项研究是创新的，因为它是第一项在受试者中调查单渠道国有企业对 多通道频谱和语音处理器的性能，通过直接操纵的程度，目前的蔓延。该研究方法结合了客观测量（ECAP），主观描述符，单通道和多通道心理物理学，以及实验信号处理的评估，以更好地了解谁可能受益于当前的焦点，以及在什么情况下。

DESCRIPTION (provided by applicant): Cochlear implants (CIs) provide excellent functional hearing to most deaf individuals, but the benefits are limited when listening in noise or to complex sounds like music. To improve cochlear implant performance we need to identify the most important cues for these difficult listening situations and find ways to present these cues through the implant. Improving spectral selectivity should improve implant performance but is limited by physical, biological and perceptual factors. For an individual implant listener, spectra selectivity may be limited by poor electrode placement and/or poor nerve survival. New techniques (current focusing) have been investigated to reduce current spread and therefore improve spectral selectivity. However, data from our lab suggest that current focusing only reduces spread of excitation (SOE) in about half of the patients tested. Performance improvements from current focusing can only be expected when the SOE is actually reduced. In the proposed experiments, we will provide the first within-subject's measurements of changes in speech in noise and music tasks (Specific Aim 3) as they relate to changes in multi-channel spectral pattern discrimination (Specific Aim 2) and reduction in single-channel SOE (Specific Aim 1). We expect to find that current focusing can result in reductions in SOE, which in turn will produce improvements in speech in noise and music performance. However, because of local neural survival, electrode placement, and variable local impedances, we expect to find that a reduction in SOE will only be achievable in a subset of patients. Therefore, we will also investigate quick (and clinically relevant) methods of predicting which patients will benefit from current focusing (experiments 2 and 3). The overall goals of this research are to determine if functional spectral resolution can be improved via current focusing for some patients and to determine in a clinically relevant procedure which patients would benefit from current focusing. We hypothesize that if current focusing can reduce the spread of excitation, then spectral resolution will be increased and improve CI performance in challenging listening conditions (e.g., speech in noise, music). The proposed research is significant because it aims to: a) evaluate the relationship between changes in SOE, multi-channel discrimination, and performance in speech and music tasks, b) improve performance for CI listeners. The research is innovative as the first study to investigate within subjects the effect of single-channel SOE on multi-channel spectral and speech processor performance by directly manipulating the degree of current spread. The research approach combines objective measures (ECAPs), subjective descriptors, single- and multi-channel psychophysics, and evaluations of experimental signal processing to better understand who might benefit from current focusing, and under what circumstances.