Using current-focusing and current-steering to increase the number of effective c

使用电流聚焦和电流引导来增加有效电流的数量

基本信息

批准号：
8247244
负责人：
David M Landsberger
金额：
$ 17.24万
依托单位：
HOUSE RESEARCH INSTITUTE
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-06-02 至 2012-05-31
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): The overall goal of this research is to develop stimulation strategies that increase the number of effective channels for cochlear implant (CI) users. Most CI users have great difficulty in challenging listening conditions (e.g., background noise, competing speech, music, etc.), due to the limited spectral resolution of the implant device. While contemporary CI devices can transmit as many as 22 physical channels (and many more virtual channels), CI users can typically access only ~8 channels. We hypothesize that CI users' functional spectral resolution is primarily limited by channel interactions, i.e., the electrical current spread between channels. One approach to reduce current spread is to utilize tripolar and/or quadrupolar stimulation modes (current focusing). However, even 22 fully independent physical channels are not sufficient to support challenging listening tasks. One approach to increase the number of channels beyond the physical number of electrodes is to simultaneously stimulate adjacent electrodes, creating virtual channels (current steering). We propose to combine current focusing with current steering to improve CI users' functional spectral resolution. If successful, combining current focusing and current steering within a signal processing strategy may allow CI users to access the additional spectral channels needed for difficult listening conditions. In order to successfully implement such a strategy, it is important to develop the basic psychophysical framework of current focusing and current steering. The following three specific aims are to collect the basic information needed to develop the next generation sound processing strategy. In Specific Aim 1, we will compare the current spread between loudness balanced stimuli with differing degrees of current focusing. We predict that for a fixed loudness level, current spread will be significantly reduced for focused stimuli. If so, focused stimulation in a signal processing strategy should reduce channel interaction and improve the functional spectral resolution. In Specific Aim 2, we will investigate perceptual effects associated with different degrees of current focusing. Anecdotal reports suggest that current focusing may result in changes in pitch (Saoji, 2007; Berenstein, 2007) and/or tonal clarity (Marzalek et al., 2007). We predict that increased focusing will provide a small but reliable improvement in tonal clarity, but will not systematically alter the perceived pitch. In Specific Aim 3, we will measure discrimination of current-steered virtual channels that can be generated between two electrodes with and without current focusing. We predict that spatial selectivity for virtual channels will be significantly improved with current focusing. Relevance: While contemporary cochlear implants (CIs) can transmit as many as 22 physical channels (and many more virtual channels), hearing impaired patients with CIs can typically access only ~8 channels. Challenging listening conditions (e.g., speech in noise, competing speech, music, etc) require significantly more channels. The proposed research is clinically relevant, as it addresses a long-standing challenge in CI research: how to increase the number of effective spectral channels.

描述（由申请人提供）：这项研究的总体目标是制定刺激策略，以增加人工耳蜗（CI）用户的有效渠道的数量。由于植入设备的光谱分辨率有限，大多数CI用户在挑战聆听条件（例如背景噪音，竞争语音，音乐等）方面都有很大的困难。尽管当代CI设备可以传输多达22个物理渠道（以及更多虚拟渠道），但CI用户通常只能访问〜8个通道。我们假设CI用户的功能频谱分辨率主要受通道相互作用的限制，即在通道之间的电流传播。减少电流传播的一种方法是利用三极和/或四极刺激模式（电流焦点）。但是，即使是22个完全独立的物理渠道也不足以支持具有挑战性的聆听任务。增加电极物理数量超出物理数量的通道数的一种方法是同时刺激相邻的电极，从而创建虚拟通道（当前转向）。我们建议将当前的聚焦与当前转向相结合，以改善CI用户的功能光谱分辨率。如果成功，将当前的焦点和当前转向组合在信号处理策略中可能会使CI用户可以访问困难聆听条件所需的其他光谱渠道。为了成功实施这种策略，重要的是要开发当前聚焦和当前转向的基本心理物理框架。以下三个具体目的是收集制定下一代声音处理策略所需的基本信息。在特定的目标1中，我们将以不同程度的当前聚焦度比较响度平衡刺激之间的电流传播。我们预测，对于固定的响度水平，对于聚焦刺激，电流的差异将大大减少。如果是这样，信号处理策略中的集中刺激应减少信道相互作用并改善功能频谱分辨率。在特定的目标2中，我们将研究与当前聚焦不同程度相关的感知效应。轶事报告表明，当前的聚焦可能会导致音高变化（Saoji，2007； Berenstein，2007）和/或音调清晰度（Marzalek等，2007）。我们预测，增加的焦点将提供较小但可靠的音调清晰度改善，但不会系统地改变感知的音高。在特定的目标3中，我们将测量可以在有和没有电流聚焦的两个电极之间生成电流的虚拟通道的歧视。我们预测，随着当前的焦点，虚拟通道的空间选择性将显着提高。相关性：尽管当代人工耳蜗（CIS）可以传输多达22个物理通道（以及更多的虚拟通道），但听力受损的CIS患者通常只能访问〜8个通道。具有挑战性的聆听条件（例如，噪音，竞争语音，音乐等中的语音）需要更多的渠道。拟议的研究在临床上具有相关性，因为它解决了CI研究中的长期挑战：如何增加有效的光谱渠道数量。