Complex sound analysis in normal and impaired ears

描述(申请人提供)：本项目的目的是确定听力困难的性质，听者听到安静的声音如纯音的能力仍然相对较好。该项目的一个特别关注点是年长的听众，他们鄙视正常的听力图，发现理解背景中的语音听起来很困难。为了进行比较，患有耳蜗性听力损失的年轻听众也将接受检查。该项目的框架围绕三个具体目标构建。第一个目的是探索在安静状态下正常阈值可能掩盖听神经水平上的永久性神经功能障碍的可能性，这种情况与噪声暴露的工作相似，表明尽管存在残留的神经损伤，但声音过度暴露后的敏感度可能会恢复。这一目标将导致更好地描述在听力明显良好的情况下存在的声音处理缺陷。第二个目标是研究语音等复杂声音引起的听觉脑干反应(ABR)。这种类型的ABR测试的使用正在迅速增长，但关于基本反应仍有许多需要了解。第二个目标的直接目的是研究言语诱发ABR中年龄相关差异的特殊情况，但更广泛的目标是利用这项研究作为一种工具，更好地理解在正常和耳蜗病听觉系统中导致言语诱发ABR产生的多种因素。最终目的是从一个新的角度来分析日常听力环境中影响言语理解的因素，在日常听力环境中，背景声音通常在时间和频率上波动，使得目标言语本身的一瞥在这些维度上以及在不同的耳朵之间动态变化。这三个目标结合在一起，提供了一系列平行研究，将显著提高我们对复杂声音(如在具有挑战性的听力环境中处理语音)的理解，即使是对听力相对较好的人也是如此。

DESCRIPTION (provided by applicant): The purpose of this project is to determine the nature of the hearing difficulties experienced by listeners whose ability to hear quiet sounds like pure tones is still relatively good. One particular focus of the project is on older listeners who, despte normal audiograms, find understanding speech in background sounds difficult. For comparison, younger listeners with cochlear hearing loss will also be examined. The framework of the project is structured around 3 Specific Aims. The first Aim explores the possibility that normal thresholds in quiet can belie permanent neural dysfunction at the level of the auditory nerve, a situation that parallels noise exposure work showing that recovery of sensitivity following acoustic over-exposure can occur despite residual nerve damage. This Aim will lead to a better delineation of the sound-processing deficits that exist in the face of apparently good hearing. The second Aim focuses on auditory brainstem responses [ABRs] evoked by complex sounds like speech. This type of ABR testing is rapidly growing in usage but much remains to be understood about the basic response. The immediate goal of the second Aim is to study the particular situation of age-related differences in the speech-evoked ABR, but the broader objective is to use this study as a vehicle to better understand the multiplicity of factors that contribute to the generation of the speech-evoked ABR both in the normal and cochlear-impaired auditory system. The final Aim contributes a new perspective on factors that affect speech understanding in everyday listening environments where the background sound is typically fluctuating in both time and frequency making the glimpses of target speech themselves dynamically vary across these dimensions as well as across ears. Together, these three Aims combine to provide a series of parallel studies that will significantly advance our understanding of the processing of complex sounds like speech in challenging listening environments, even for people with relatively good hearing.