The Impact of Frequency Compression on Cortical Evoked Potentials and Perception

描述(由申请人提供)：听力学领域的核心挑战之一是验证婴幼儿的最佳助听器适配性，这些婴幼儿无法可靠地提供关于助听器设置的详细主观反馈。听力专家通常必须依靠父母的报告来指导助听器设置的选择，而获得这些信息可能需要几周或几个月的时间。最近，人们已经证实，皮层听觉诱发电位(CAEP)是对听觉皮质活动的客观记录，可以替代父母的报告来配戴助听器。虽然CAEP可以在临床环境中使用各种助听器增益特性来确定婴儿的声音可听性，但目前还不存在客观措施来指导为单个助听器用户选择最佳频率压缩参数。频率压缩是一种助听器信号处理策略，用于系统地降低高频声音，目前成人和儿童助听器用户通常启用这种策略。它可以有效地提高具有倾斜高频听力损失的个人的高频语音的可听性，因为它将这些语音从听力受损区域移动到听力更好的区域。不幸的是，频率压缩算法还可能导致不同语音之间的频谱对比度降低-特别是在使用更激进的频率压缩设置时。声学变化复合体(ACC)是传统记录的CAEP的一种变体，ACC的存在与检测到持续刺激中的变化相关。对于不能提供关于频率压缩设置的主观反馈的助听器用户来说，ACC可能是客观评估频率压缩参数对听觉皮质中频谱对比声音表示的影响的理想方法。本项目的具体目的是确定在频率压缩和听力损失条件下，皮层诱发电位与心理物理表现之间的关系。为了解决这一特定目标，提出了一系列三个实验。在第一个实验中，将从正常听力受试者那里获得ACC反应、心理物理光谱辨别阈值和元音识别分数，这些受试者听过使用定制软件以频率压缩的刺激。在第二个实验中，这些相同的测量将在正常听力受试者中完成，这些受试者听着额外处理的刺激以模拟高频听力损失。最后，在第三个实验中，将对一组患有高频感音神经性听力损失的参与者进行测试。这三个实验的结果将描述在一系列频率压缩条件下感知和皮质诱发反应之间的关系，填补了我们知识库中的一个关键空白，并潜在地建立了适用于临床儿科助听器配戴所需的基于证据的客观结果衡量标准。 公共卫生相关性：拟议的研究将有助于在频率压缩条件下建立听觉皮质中声音的感知和编码之间的关系。所提出的这种类型的客观措施可以解决临床儿科助听器试戴中未得到满足的需求，从而改善年轻助听器使用者对声音的可听性和辨别能力。

DESCRIPTION (provided by applicant): One of the central challenges in the field of audiology is the verification of optimal hearing aid fitting in infants and young children who cannot reliabl provide detailed subjective feedback about hearing aid settings. The audiologist often must depend on parental report to guide the selection of hearing aid settings and obtaining that information may take weeks or months. Recently, it has been established that cortical auditory evoked potentials (CAEPs), objective recordings of activity in the auditory cortex, may serve as an alternative to parental report for fitting hearing aids. While CAEPs can be used in clinical settings to determine audibility of sound for infants using various hearing aid gain characteristics, at this time, no objective measure exists to guide the selection of optimal frequency compression parameters for an individual hearing aid user. Frequency compression is a hearing aid signal-processing strategy for systematically lowering high frequency sounds that is now commonly enabled for adult and child hearing aid users. It can be effective at increasing the audibility of high frequency speech sounds for individuals with sloping, high frequency hearing loss because it moves those speech sounds from a region of hearing impairment to a region of better hearing. Unfortunately, frequency compression algorithms can also cause a reduction in the spectral contrast between different speech sounds - particularly when more aggressive frequency compression settings are used. The acoustic change complex (ACC) is a variant of traditionally recorded CAEPs and the presence of an ACC is correlated with detection of change in an ongoing stimulus. The ACC may be ideal to evaluate objectively the effects of frequency compression parameters on the representation of spectrally contrasted sounds in the auditory cortex in hearing aid users who are unable to provide subjective feedback on frequency compression settings. The specific aim of this project is to determine the relationship between cortical evoked potentials and psychophysical performance in conditions of frequency compression and hearing loss. A series of three experiments are proposed to address this specific aim. In the first experiment, ACC responses, psychophysical spectral discrimination thresholds, and vowel identification scores will be obtained from normal hearing participants listening to stimuli that have been compressed in frequency using custom software. In the second experiment, these same measures will be completed in normal hearing participants listening to stimuli additionally processed to simulate high frequency hearing loss. Finally, in the third experiment, a heterogeneous group of participants with high frequency sensorineural hearing loss will be tested. The results of these three experiments will describe the relationship between perception and cortical evoked responses in a range of frequency compression conditions, filling a critical gap in our knowledge base and potentially establishing a needed evidence-based objective outcome measure applicable to clinical pediatric hearing aid fitting. PUBLIC HEALTH RELEVANCE: The proposed research will serve to establish relationships between perception and the encoding of sounds in the auditory cortex in conditions of frequency compression. An objective measure of the type proposed may address an unmet need in clinical pediatric hearing aid fitting, resulting in improved audibility and discriminability of sounds by young hearing aid users.