Individual differences in supra-threshold sound encoding

超阈值声音编码的个体差异

基本信息

批准号：
10116894
负责人：
Barbara Shinn-Cunningham
金额：
$ 24.2万
依托单位：
CARNEGIE-MELLON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-03-01 至 2022-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10116894
关键词：
Individual differences supra threshold sound

项目摘要

DESCRIPTION (provided by applicant): A long-standing puzzle is why listeners with normal hearing thresholds show such enormous variation in performance on other auditory tasks. Differences among "normal hearing" listeners are particularly pronounced when tasks involve separating multiple sound sources, such as when listeners must rely on selective auditory attention. Recent animal work shows that noise exposure can damage the synaptic efficacy of auditory nerve fibers without permanently altering hearing thresholds, producing auditory neuropathy. Low-spontaneous rate auditory nerve fibers, which are especially important for encoding the temporal content of supra-threshold sound, may be preferentially affected. Consistent with animal studies, our preliminary results in listeners with normal thresholds suggest that inter-subject performance differences on selective attention tasks correlate with psychophysical and physiological measures designed to reveal the fidelity of temporal coding at supra-threshold levels. We hypothesize that auditory neuropathy may be much more common than previously recognized: young listeners with normal hearing thresholds may differ in the fidelity with which their auditory nerve fibers encode supra-threshold temporal information, affecting their ability to communicate in everyday settings. Sound exposure leads to supra-threshold deficits in animals without threshold shifts; thus, we also postulate that listeners with conventionally defined hearing loss from noise exposure likely also suffer from supra-threshold deficits that contribute substantially to communication difficulties. The main objective of this project is to quantify auditory neuropathy in a cohort of young, "normal hearing" listeners. We will also explore how supra-threshold encoding contributes to performance differences in listeners with elevated thresholds due to noise exposure. We will: Aim 1) characterize individual differences in supra-threshold sound encoding in subcortical portions of the auditory pathway; Aim 2) characterize individual differences in the ability to selectively attend, and relate them to differences in coding fidelity; and Aim 3) characterize how supra-threshold sound encoding fidelity contributes to performance differences for listeners with mild to moderate high-frequency hearing loss. We will compare physiological (brainstem responses, distortion product otoacoustic emissions, and cortical responses) and behavioral measures from the same listeners and use computational models to unravel the relationships between these metrics. Our results will quantify how peripheral encoding of supra-threshold sound differs across listeners with both normal and elevated thresholds, and will establish how supra-threshold differences affect the ability to communication in common social settings. Our results could lead to a clinical test of supra-threshold hearing fidelity, quantifying one factor leading to differences in communication ability amongst listeners with similar audiograms.

描述（由申请人提供）：一个长期存在的谜题是，为什么具有正常听力阈值的听众在其他听觉任务上的表现表现出如此巨大的差异。当任务涉及分离多个声源时，例如当听众必须依赖选择性的听觉注意力时，“正常听力”听众之间的差异尤其明显。最近的动物研究表明，噪音暴露会损害听觉神经纤维的突触功效，但不会永久改变听力阈值，从而产生听觉神经病变。低自发率听觉神经纤维对于编码超阈值声音的时间内容特别重要，可能会优先受到影响。与动物研究一致，我们对具有正常阈值的听众的初步结果表明，选择性注意任务上的受试者间表现差异与旨在揭示超阈值水平的时间编码保真度的心理物理和生理测量相关。我们假设听觉神经病变可能比以前认识到的更为常见：具有正常听力阈值的年轻听众可能在听觉神经纤维编码超阈值时间信息的保真度方面存在差异，从而影响他们在日常环境中的交流能力。声音暴露会导致动物出现超阈值缺陷，而没有阈值变化；因此，我们还假设听众传统上定义的噪声暴露造成的听力损失也可能遭受超阈值缺陷，这在很大程度上导致了沟通困难。该项目的主要目标是量化一群年轻“听力正常”听众的听觉神经病变。我们还将探讨超阈值编码如何导致因噪声暴露而阈值升高的听众的性能差异。我们将：目标 1）表征听觉通路皮层下部分超阈值声音编码的个体差异；目标 2) 描述选择性参加能力的个体差异，并将其与编码保真度的差异；和目标 3）描述了超阈值声音编码保真度如何影响轻度至中度高频听力损失的听众的性能差异。我们将比较同一听众的生理（脑干反应、失真产物耳声发射和皮质反应）和行为测量，并使用计算模型来阐明这些指标之间的关系。我们的结果将量化正常阈值和升高阈值的听众之间超阈值声音的外围编码如何不同，并将确定超阈值差异如何影响常见社交环境中的沟通能力。我们的结果可能会导致临床超阈值听力保真度测试，量化导致具有相似听力图的听众之间沟通能力差异的一个因素。