Behavioral and Cortical Signatures of Reduced Auditory Spatial Tuning with Age

描述（由申请人提供）：在70岁以上的成年人中，临床显著听力损失的患病率约为63%（Lin等人，2011年）。此外，老年人中未经治疗的听力损失与更快的认知下降和更大的痴呆风险有关（Lin等人，2013年）的报告。在嘈杂的环境中难以跟随对话是最常见的听力相关投诉，无论听力是否通过放大来补偿。人类必须专注于所需声源的非凡能力（例如，语音、音乐、环境声音）在存在竞争声音的情况下在很大程度上取决于空间听觉。众所周知，随着正常衰老，空间听力的许多方面都会下降，但导致这种下降的机制尚不清楚。同样，众所周知，自上而下控制的感觉处理，包括集中注意力，随着年龄的增长而下降，但与年龄相关的变化，选择性听觉空间注意力还没有得到很好的记录和了解甚少。本计画的目标是利用同步的脑电描记术与行为量测，来探讨老年人听觉空间调谐的过程。实验已经被设计来评估与潜在变化相关的特定假设，在对立通道（OC）的空间处理机制。实验集中于低频刺激，因为低于~1500 Hz的空间线索由耳间时间差主导，并且时间缺陷是老年性耳聋的标志。目标1的目标是确定相对于年轻听众，老年听众（具有正常听力灵敏度）是否表现出改变的空间调谐。第二个目标是使用空间调谐的措施， 评估OC模型的潜在机制以及年龄相关的抑制下调和/或时间精度对空间处理缺陷的潜在影响。在目标2中，平行实验被用来探讨的可能性，随着年龄的增长，扩大空间注意力进一步限制空间优势，老年听众。在 此外，这项工作的长期目标是确定适当的诊断方法和补救目标，评估并可能改变听力增强设备和听觉训练方法用于改善现有缺陷的方式，并开发有用的结果指标，以减缓或逆转与年龄相关的听力损失。概述的培训计划提供了一个强大的辅导环境，无论是从直接的实验室设置以及机构设置。研究金申请人决心努力建立必要的工具和经验，在未来过渡到一个独立的学术研究生涯。

DESCRIPTION (provided by applicant): The prevalence of clinically-significant hearing loss is ~63% in adults over 70 years of age (Lin et al., 2011). Moreover, untreated hearing loss in older adults has been linked to more rapid cognitive declines and greater risk of dementia (Lin et al., 2013). Difficulty following conversations in noisy settings is the most common hearing-related complaint, regardless of whether audibility is compensated by amplification. The remarkable ability humans have to focus on a desired sound source (e.g., speech, music, environmental sounds) in the presence of competing sounds depends to a large extent on spatial hearing. It is known that many aspects of spatial hearing decline with normal aging but the mechanisms responsible for that decline are not known. Likewise, it is known that top-down control of sensory processing, including focused attention, declines with age but age-related changes in selective auditory spatial attention have not been well documented and are poorly understood. The goal of this project is to investigate the processes involved in auditory spatial tuning in oldr listeners, leveraging simultaneous electroencephalography and behavioral measurements. Experiments have been designed to evaluate specific hypotheses associated with potential changes in the opponent- channel (OC) mechanisms underlying spatial processing. The experiments focus on low-frequency stimuli, since spatial cues below ~1500 Hz are dominated by interaural time differences, and timing deficits are a hallmark of presbycusis. A goal of Aim 1 is to determine whether or not older listeners (with normal hearing sensitivity) exhibit altered spatial tuning relative to younger listeners. A second goal is to use measures of spatial tuning to evaluate the potential mechanisms underlying the OC model and the potential influence of either age-related down-regulation of inhibition and/or temporal precision on spatial processing deficits. In Aim 2, parallel experiments are used to probe the possibility that, with advancing age, broadened spatial attention further limits spatial advantages available to older listeners. In addition, long-term goals of this work are to identify appropriate diagnostic methods and remediation targets, to evaluate and possibly alter the way hearing enhancement devices and auditory training methods may be used to ameliorate existing deficits, and to develop outcome metrics useful should treatments that slow or reverse age-related hearing loss be discovered. The training program outlined provides a strong mentoring environment both from an immediate laboratory setting as well as the institutional setting. The fellowship applicant is determined to work towards establishing the tools and experience necessary to transition in the future to an independent academic research career.