Optimized Conditioned Processing for Cochlear Implants

描述(由申请人提供)：目前，相当大比例的现代人工耳蜗术后患者可以在安静状态下获得高水平的语音感知。然而，在嘈杂的背景下，特别是当噪声与语音竞争时，语音感知会显著受损。在噪声中改善语音感知的一种可能的方法是改善电刺激听神经纤维的放电模式中语音的时间表征。这种方法也有望改善双侧植入受者在需要对耳间时序进行脑干分析的任务中的表现。详细的生物物理模型和动物研究表明，改进的时间表征可以通过使用“条件性刺激”来实现。“条件性刺激”是一系列未调制的高频率脉冲，它使听神经元的活动与竞争信号失去同步。在一些受试者的安静和/或噪声中，这一过程的使用显著地提高了言语知觉，但在另一些受试者中却没有。这项工作的目标是优化语音信号和条件反射的呈现，以最大限度地提高单侧植入者在安静和噪声中的言语知觉，并改善双侧植入者对基于时间的偏侧化和双耳去掩蔽的感知。因为时间音调机制如果要有用，就需要准确的位置信息，并且音调被认为对竞争语音中的语音辨别至关重要，因此在有条件的语音处理器中将处理滤波器到电极的映射，以最大限度地提高对稳态噪声中的应答者的测试的性能，以及在语音形状噪声中的提示句子的性能。这一结果将使单侧和双侧人工耳蜗术后条件处理器的优化成为可能。在那些对生理范围内的电刺激具有耳间时序感知的双耳植入者中，这项工作有可能在目前通过耳间幅度差异提供的基础上，从临床语音处理器中提供显著的额外双耳益处。在单侧植入物中，这项工作已经在有限数量的受试者中显示出实质性的好处；我们的目标是将这些好处传递给更广泛的植入物接受者。

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.