Signal Processing Along the Auditory Pathway: Changes Following Noise Exposure

项目总结/摘要 军事人员的感音神经性听力损失（SNHL）通常是由噪声或爆炸相关的 听觉外周（耳蜗）和/或中枢系统损伤，包括完整性改变 耳蜗分隔和听觉通路上沿着的细胞死亡。听力损失通常是永久性的， 对于持续性损伤没有治愈方法。目前的建议旨在表征信号处理 沿着听觉通路通过建立结构-功能关系，在两个正常的耳朵， 各种SNHL。总的目标是通过分离SNHL的基因， 耳蜗（感觉）和耳蜗后（神经）损失的贡献。我们将结合联合收割机 测量技术（光学相干断层扫描，OCT）与记录，已经在 诊所[即，耳道畸变产物耳声发射（DPOAE）和频率跟踪 因此，耳蜗力学和噪音或爆炸的有害影响- 可以在沿着听觉通路的沿着不同阶段评估暴露。截至目前，OCT从 耳蜗不能从人类记录，但我们希望DPOAE和FFR的组合提供了一个 SNHL的鉴别诊断，区分感觉与神经成分的损伤。目标1 该提案将通过确定DPOAE和FFR与耳蜗的关系， 正常沙鼠耳朵的微观力学。实验结果将用于开发最佳近似 使用DPOAE和FFR预测耳蜗功能的BAM模型。在Aim 2中，我们将探讨各种 SNHL的形式改变了潜在的耳蜗力学与特定的设计，以区别诊断 感觉和神经听力损失，并确定如何使用以下组合来量化这些变化： DPOAE和FFR测量。这些结果将进一步验证根据目标1制定的BAM。在目标3 我们将把从动物身上获得的知识应用于患有不同类型SNHL的人类， 使用DPOAE、FFR和BAM对SNHL进行临床鉴别诊断。使用直接和 同时测量沿着听觉通路，在这些条件下的信号处理将是 详细量化。拟议的研究将促进我们对声音处理的理解， 听觉系统，特别是在低频，这是重要的讲话和提供关键信息， 提高我们诊断和开发SNHL新疗法的能力。这将有利于我们的退伍军人，许多人， 噪音/爆炸引起的听力损失。

Project Summary/Abstract Sensorineural hearing loss (SNHL) in military personnel is commonly caused by noise- or blast-related damage to the auditory periphery (cochlea) and/or the central system, which includes changes in the integrity of the cochlear partition and cellular death along the auditory pathway. Hearing loss is often permanent, and there exist no cures for sustained injuries. The current proposal seeks to characterize the signal processing along the auditory pathway by establishing the structure-function relationship in both normal ears and with various types of SNHL. The overall goal is to improve the diagnosis of SNHL within the clinic by separating contributions from cochlear (sensory) and retro-cochlear (neural) loss. We will combine a novel, state-of-the-art measurement technique (optical coherence tomography, OCT) with recordings that are already available in the clinic [i.e., distortion product otoacoustic emissions (DPOAE) in the ear canal and frequency-following responses (FFR) from the cortex] so that the cochlear mechanics and the detrimental effects of noise- or blast- exposure can be evaluated at different stages along the auditory pathway. As of now, OCT measures from the cochlea cannot be recorded from humans, but we expect that the combination of DPOAE and FFR provides a differential diagnosis of SNHL that distinguishes damage of the sensory versus neural component. Aim 1 of this proposal will form the foundation of the study by determining how DPOAEs and FFRs relate to cochlear micromechanics in normal gerbil ears. The experimental results will be used to develop a Best Approximation Model (BAM) that will predict cochlear function using DPOAEs and FFRs. In Aim 2 we will explore how various forms of SNHL change the underlying cochlear mechanics with the specific design to differentially diagnose sensory and neural hearing loss and establish how these changes can be quantified using a combination of DPOAE and FFR measurements. These results will further validate the BAM developed under Aim 1. In Aim 3 we will apply the knowledge obtained in animals to humans that suffer from different types of SNHL to improve the clinical differential diagnosis of an SNHL using DPOAEs, FFRs, and the BAM. Using direct and simultaneous measurements along the auditory pathway, the signal processing under these conditions will be quantified in detail. The proposed research will advance our understanding of sound processing within the auditory system, especially at low frequencies that are important for speech and provide critical information to improve our ability to diagnose and develop new treatments for SNHL. This will benefit our Veterans, many of whom suffer from noise/blast-induced hearing loss.