Improved perception of temporal information in electrical signals for profoundly deaf users of cochlear implants

该项目的最终目标是提高人工耳蜗使用者理解语音的能力。语音信号振幅随时间变化的方式为听者提供了关于语音信号内容的有用信息。目前人工耳蜗的声信号幅值转换为电信号幅值的方法没有考虑到多电极电刺激中存在的非常显著的响度总和。也就是说，当在短时间内在不同的电极上有多个连续的电流脉冲时，产生的响度大于单个电流脉冲产生的响度。由于缺乏对响度叠加效应的考虑，导致植入耳蜗的响度变化不能准确表征声信号的振幅变化。本项目旨在通过研究响度和的影响，为人工耳蜗植入者提供一种更准确表征语音信号振幅波动的实用方法。该项目的第二个目标是研究使用不同形状的电流脉冲对感知的影响。生理学实验的证据表明，使用不同的形状可能会引起电刺激，激活每个电极上间隔更窄的听觉神经元。这两项研究结果的应用将直接改善人工耳蜗植入者对言语和其他声音的感知，从而提高其沟通能力和生活质量。

The ultimate goal of this project is to improve the ability of cochlear implant users to understand speech. The way in which a speech signal varies in amplitude over time provides useful information to the listener about the content of the speech signal. Currently, the way that the acoustic signal amplitude is converted to electrical signal amplitude for cochlear implantees does not take into consideration the very significant loudness summation present in multiple-electrode electrical stimulation. That is, when there are multiple sequential current pulses on different electrodes over a short time, the resultant loudness is greater than the loudness due to individual current pulses. The lack of consideration of loudness summation effects has led to the amplitude variations in the acoustic signal not being accurately represented in the loudness variation perceived by the cochlear implantee. This project aims to develop a practical way of more accurately representing speech signal amplitude fluctuations for cochlear implantees by studying the effects of loudness summation. A second aim of the project is to study the effects on perception of using differently-shaped current pulses from those currently used. There is evidence from physiology experiments that using different shapes might cause the electrical stimulation to activate a more narrowly-spaced set of auditory neurons for each electrode. The application of results of both these studies will lead directly to improved perception of speech and other sounds by cochlear implantees, thus improving their communication ability and quality of life.