Effects of Hearing Aid Amplification on Robust Speech Coding

摘要助听器能够帮助有听力障碍的人恢复部分听力，但背景噪声仍然是一个重要的问题。不幸的是，人们对语音是如何在听觉系统中编码的知之甚少，特别是在有假肢放大器的受损系统中。更好地了解助听器对噪声中语音编码的影响可能会为这些设备的设计带来新的见解。越来越多的证据表明，跨纤维神经编码对语音感知很重要，但目前还没有将时空编码与助听器放大联系起来的研究。本研究的目的是描述助听器如何在听觉神经水平上影响噪声中的元音编码，并评估一种旨在增强跨纤维编码的新型助听器解决方案。将在无噪声和有背景噪声的情况下比较速率位置、时间位置和时空编码方案的强度。指导这项工作的一般假设是，尽管目前的频率相关增益策略不能改善时空编码，但基于生理相位效应的新型放大技术可以改善时空编码。将量化两种助听器算法对噪声（相对于正常和受损）中元音编码的影响：线性助听器算法和多通道宽动态范围压缩算法。此外，还将评估全通滤波器增强受损时空模式的能力。提出了两种相位校正算法：一种是以元音共振峰为中心的全通滤波器，另一种是以每个谐波分量为中心的全通滤波器。所提出的神经生理学实验将为助听器放大对噪声中元音听神经编码的影响提供有价值的数据。这些数据将有助于理解扩音的影响和设计助听器，使患者更好地理解噪音中的言语。

DESCRIPTION (provided by applicant): Abstract Hearing aids are able to restore some hearing abilities for people with auditory impairments, but background noise remains a significant problem. Unfortunately, very little is understood about how speech is encoded in the auditory system, particularly in impaired systems with prosthetic amplifiers. A better understanding of the effects of hearing aids on speech coding in noise could lead to new insights for the design of these devices. There is growing evidence that across-fiber neural coding is important for speech perception, but there is no research that relates spatiotemporal coding and hearing aid amplification. The goal of the proposed research is to characterize how hearing aids affect vowel coding in noise at the level of the auditory nerve, and to evaluate a novel hearing aid solution that is designed to enhance across- fiber coding. The strength of rate-place, temporal-place, and spatiotemporal coding schemes will be compared in quiet and in the presence of background noise. The general hypothesis guiding the proposed work is that, although current frequency-dependent gain strategies do not improve spatiotemporal coding, novel amplification techniques based on physiological phase effects can improve spatiotemporal coding. The effects of two hearing aid algorithms on vowel coding in noise (relative to normal and impaired) will be quantified: a linear hearing aid algorithm and a multichannel wide-dynamic-range compression algorithm. In addition, the ability of all-pass filters to enhance impaired spatiotemporal patterns will be evaluated. Two phase-correction algorithms are proposed: one with all-pass filters centered on the formants of a vowel, and another with all-pass filters centered on each harmonic component. The proposed neurophysiological experiments will provide valuable data about the effects of hearing aid amplification on auditory nerve coding of vowels in noise. These data will be useful for understanding the effects of amplification and designing hearing aids that allow patients to better understand speech in noise. PUBLIC HEALTH RELEVANCE: The goal of this project is to evaluate and enhance the effect of hearing aids on the representation of speech in the auditory nerve. The neural data collected in these experiments will provide fundamental knowledge about the effects of amplification in noise, which can be used to develop new technologies that will improve the quality of life for people with hearing impairment.