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

描述(申请人提供)：人工耳蜗(CI)为大多数聋人提供了良好的功能听力，但当在噪音或复杂的声音(如音乐)中听时，其好处是有限的。为了提高人工耳蜗的性能，我们需要为这些困难的听力情景识别最重要的线索，并找到通过植入物呈现这些线索的方法。提高光谱选择性应该会改善植入物的性能，但受到物理、生物和感知因素的限制。对于单个植入型听者，光谱选择性可能受到电极放置不良和/或神经存活不良的限制。人们研究了新的技术(电流聚焦)来减少电流扩散，从而提高光谱选择性。然而，来自我们实验室的数据表明，电流聚焦只减少了大约一半接受测试的患者的兴奋扩散(SOE)。只有在实际减少国有企业的情况下，才能预期当前聚焦带来的绩效改善。在拟议的实验中，我们将提供第一次受试者内部对噪音和音乐任务中语音变化的测量(特定目标3)，因为它们与多通道频谱模式识别的变化(特定目标2)和单通道SOE的减少(特定目标1)有关。我们预计会发现，当前的关注可以导致国有企业的减少，这反过来将 改善噪音和音乐表演中的语音。然而，由于局部神经存活、电极放置和可变的局部阻抗，我们期望发现SOE的减少只能在部分患者中实现。因此，我们还将研究预测哪些患者将从当前聚焦中受益的快速(和临床相关)方法(实验2和3)。这项研究的总体目标是确定是否可以通过当前聚焦提高某些患者的功能光谱分辨率，并在临床相关的过程中确定哪些患者将从当前聚焦中受益。我们假设，如果电流聚焦可以减少激励的传播，那么频谱分辨率将会提高，并在具有挑战性的听力条件下(例如，噪声中的语音、音乐)改善CI性能。这项研究具有重要意义，因为它旨在：a)评估SOE的变化、多通道辨别与语音和音乐任务中的表现之间的关系；b)提高CI听者的表现。这项研究具有创新性，因为它是第一个在受试者内部调查单渠道国有企业对 多通道频谱和语音处理器通过直接控制电流扩展的程度来实现性能。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对实验信号处理的评估，以更好地了解谁可能从当前的聚焦中受益，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.