Optimized Conditioned Processing for Cochlear Implants

描述（由申请人提供）：现代人工耳蜗受者中有相当比例的人在安静环境下具有高水平的言语感知能力。然而，在嘈杂的背景下，特别是如果这种噪音是竞争性的语音，语音感知会受到严重损害。改善噪声环境下语音感知的一种可能方法是改善电刺激听觉神经纤维放电模式下语音的时间表征。该方法也有望改善双侧植入物受者在需要脑干分析耳间时间的任务中的表现。详细的生物物理模型和动物研究已经证明，改善时间表征可以通过使用“条件反射刺激”来完成——一组未调制的高速率脉冲，使听觉神经元的活动与竞争信号去同步。使用这种方法，一些受试者在安静和/或噪音环境下的言语感知能力显著提高，而另一些受试者则没有。本研究的目标是优化语音信号和调节条件的呈现，以最大限度地提高单侧种植体受者在安静和噪声条件下的语音感知，并改善双侧种植体的颞侧化和双耳揭膜感知。由于时间音高机制需要准确的位置信息，如果它们是有用的，并且音高被认为是竞争语音中语音辨别的关键，因此将在条件语音处理器中操纵滤波器到电极的映射，以最大限度地提高在稳态噪声、“咿呀学语噪声”、时间调制噪声以及语音形状噪声中提示句子的测试中的表现。结果将允许优化条件处理器为单侧和双侧人工耳蜗受者。对于那些在生理范围内对电刺激有耳际时间感知的双侧植入者，这项工作有可能为临床语音处理器提供显著的额外双耳益处，而不是目前通过耳际振幅差异获得的益处。在单侧植入者中，这项工作已经在有限数量的受试者中证明了实质性的益处；我们的目标是将这些益处带给更多的种植体接受者。

DESCRIPTION (provided by applicant): High levels of speech perception in quiet are currently available to a significant percentage of modern cochlear implant recipients. In a noisy background, however, particularly if that noise is competing speech, speech perception is dramatically impaired. One possible method for improving speech perception in noise is to improve the temporal representation of speech in discharge patterns of electrically stimulated auditory nerve fibers. This method would also be expected to improve the performance of bilateral implant recipients on tasks requiring brainstem analysis of interaural timing. Detailed biophysical models and animal studies have demonstrated that improved temporal representation can be accomplished through the use of "conditioning stimuli" - trains of unmodulated high-rate pulses that desynchronize activity of auditory neurons to competing signals. Use of this procedure has led to dramatically increased speech perception in quiet and/or noise in some subjects, but not in others. The goal of the proposed work is to optimize the presentation of both the speech signal and the conditioner so as to maximize speech perception in quiet and noise for unilateral implant recipients, as well as improve perception of temporally-based lateralization and binaural unmasking in bilateral implantees. Because temporal pitch mechanisms demand accurate place information if they are to be useful, and pitch is thought critical for speech discrimination in competing speech, filter-to-electrode mappings will be manipulated in conditioned speech processors to maximize performance on a test of spondees in steady-state noise, "babble noise", temporally modulated noise, as well as on HINT sentences in speech-shaped noise. The results will allow optimization of conditioned processors for unilateral and bilateral cochlear implant recipients. In those bilateral implant recipients who have interaural timing perception for electrical stimuli in the physiologic range, this work has the potential to provide significant additional binaural benefits from a clinical speech processor beyond those currently available via interaural amplitude differences. In unilateral implantees, this work has already demonstrated substantial benefit in a limited number of subjects; it is our goal to deliver these benefits to the broader population of implant recipients.