Auditory Function at the Base of the Human Cochlea

人类耳蜗基部的听觉功能

• 批准号: 8717909
• 负责人: James Braden Dewey
• 金额: $ 3.57万
• 依托单位: NORTHWESTERN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8717909
• 关键词: Address; Adult; Affect; Aging; Animals; Auditory; Back; Behavioral; Calibration; Characteristics; Cochlea; Cochlear Hearing Loss; Data; Development; Diagnostic; Ear; Early Diagnosis; Evaluation; External auditory canal; Frequencies; Functional disorder; Future; Generations; Goals; Hearing; Human; Individual; Intervention; Investigation; Knowledge; Measurement; Measures; Mechanics; Mediating; Outer Hair Cells; Pattern; Physiological; Physiology; Prevention strategy; Process; Property; Relative (related person); Reporting; Research; Shapes; Stimulus; Structure; Suggestion; Syncope; Testing; Therapeutic; Work; base; hearing impairment; improved; middle ear; otoacoustic emission; ototoxicity; prevent; public health relevance; response; sound; theories; tool; transmission process

DESCRIPTION (provided by applicant): Hearing loss due to aging and other damaging exposures often progresses from high to low frequencies. The ability to detect these progressive and cumulative forms of hearing loss, as well as to evaluate strategies for prevention or intervention, therefore requires diagnostic tools that are capable of probing cochlear status up to the highest range of human hearing. However, our knowledge of the physiology and mechanics underlying auditory function at the basal end of the human cochlea, where high frequencies are encoded, is limited. In addition, the basic properties and potential utility of objective measures f hearing function, such as otoacoustic emissions (OAEs), faint sounds recorded in the ear canal that originate from active, outer hair cell- mediated processes in the cochlea, have been relatively unexplored at frequencies above the conventional audiometric range (> 8 kHz). In particular, there are few reports of OAEs evoked by single tones, termed stimulus-frequency OAEs (SFOAEs), at high frequencies. It is unknown whether SFOAE generation mechanisms extend to the basal end of the cochlea, how SFOAE properties are related to cochlear status above 8 kHz, and whether the amount of SFOAE energy reaching the ear canal is especially limited at high frequencies by characteristics of middle-ear transmission. To address these questions, we propose to (1) determine how SFOAE amplitudes are related to the level and configuration of behavioral pure-tone hearing thresholds at frequencies above 8 kHz, and (2) compare SFOAE amplitudes to the strength of a related audiometric phenomenon, termed "threshold fine structure," across a wide range of frequencies. This fine structure is thought to arise when a portion of the SFOAE evoked by the test tone is not transmitted out to the ear canal, but instead is reflected back at the middle-ear boundary, thus re-stimulating the cochlea. Through detailed investigation of these phenomena in clinically normal-hearing adults, we expect that SFOAE amplitudes will be significantly correlated with behavioral hearing thresholds, and will be markedly reduced in the presence of sloping threshold configurations, suggesting that SFOAEs are highly dependent on cochlear status. In addition, we expect that SFOAE amplitudes and the strength of threshold fine structure will co-vary in a similar fashion both above and below 8 kHz, suggesting that transmission via the middle ear is not especially limiting at high frequencies. The results will critically inform theories of OAE generation, cochlear mechanics and middle-ear transmission, and will aid in the development of OAE-based diagnostic tools for assessing cochlear function at frequencies above the conventional audiometric range.

描述（由申请人提供）：由于老化和其他损害性暴露导致的听力损失通常从高频到低频发展。因此，检测这些渐进和累积形式的听力损失以及评估预防或干预策略的能力需要能够探测耳蜗状态的诊断工具， 人类听觉的最高范围。然而，我们对人类耳蜗基端听觉功能的生理学和力学知识是有限的。此外，在高于常规听力范围（> 8kHz）的频率下，听力功能的客观测量的基本性质和潜在效用，诸如耳声发射（OAE），在耳道中记录的源自耳蜗中的活跃的外毛细胞介导的过程的微弱声音，相对未被探索。特别是，有几个报告诱发的耳声发射的单音，称为刺激频率耳声发射（SFOAE），在高频率。目前尚不清楚SFOAE产生机制是否延伸到耳蜗的基底端，SFOAE特性如何与8 kHz以上的耳蜗状态相关，以及到达耳道的SFOAE能量的量是否特别受限于中耳传输的特征。为了解决这些问题，我们建议（1）确定SFOAE幅度如何与8 kHz以上频率的行为纯音听阈的水平和结构相关，以及（2）在宽频率范围内将SFOAE幅度与相关听力现象的强度进行比较，称为“阈值精细结构”。这种精细结构被认为是当测试音诱发的SFOAE的一部分没有被传输到耳道，而是在中耳边界反射回来，从而重新刺激耳蜗时出现的。通过对临床听力正常成人的这些现象的详细调查，我们预计SFOAE振幅将与行为听阈显著相关，并且在存在倾斜阈值配置时将显著降低，这表明SFOAE高度依赖于耳蜗状态。此外，我们预计SFOAE振幅和阈值精细结构的强度将以类似的方式在8 kHz以上和以下共同变化，这表明通过中耳的传输在高频下并不特别受限。研究结果将为OAE产生、耳蜗力学和中耳传输的理论提供重要信息，并将有助于开发基于OAE的诊断工具，用于在高于常规听力范围的频率下评估耳蜗功能。