Effects of Sensorineural Hearing Loss on Robust Speech Coding

感音神经性听力损失对鲁棒语音编码的影响

• 批准号: 9387430
• 负责人: Michael G Heinz
• 金额: $ 32.23万
• 依托单位: PURDUE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-18 至 2019-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9387430
• 关键词: Acoustic Nerve; Address; Affect; Anatomy; Animals; Audiometry; Auditory; Behavioral; Biological Assay; Brain Stem; Characteristics; Chinchilla (genus); Clinical; Cochlear nucleus; Code; Cues; Data; Detection; Development; Diagnostic; Diagnostic tests; Discrimination; Dissociation; Ear; Electrophysiology (science); Equilibrium; Event; Fiber; Frequencies; Functional disorder; Funding; Grant; Hair Cells; Hearing Aids; Human; Kale - dietary; Link; Location; Measures; Modeling; Music; Nerve Fibers; Neurons; Noise; Noise-Induced Hearing Loss; Pathway interactions; Patients; Pattern; Phase; Physiological; Prevalence; Psychometrics; Pure-Tone Audiometry; Rehabilitation therapy; Role; Sensorineural Hearing Loss; Speech; Speech Perception; Structure; Synapses; Techniques; Temporary Threshold Shift; Training; Translating; Travel; Work; Workplace; base; behavior measurement; clinical diagnostics; clinical practice; design; experience; experimental study; hearing impairment; neurophysiology; programs; public health relevance; relating to nervous system; response; sound; spatiotemporal; translational impact

DESCRIPTION (provided by applicant): Significant perceptual and physiological aspects of sensorineural hearing loss (SNHL) remain "hidden" from standard clinical diagnostics (i.e., pure tone audiometry, which measures the ear's sensitivity in quiet). Suprathreshold deficits in temporal processing occur in many listeners with SNHL, even at frequencies with a normal audiometric threshold. Furthermore, significant permanent cochlear synaptopathy (up to 50% loss) can occur in noise-exposed ears that "only" experience a temporary threshold shift. The current proposal provides a systematic approach to directly link physiological and behavioral effects of noise-induced hearing loss in cases of both temporary and permanent threshold shift. These experiments were designed based on evidence from the auditory nerve that physiological deficits in temporal coding due to SNHL may be hidden in quiet conditions, may be different for narrowband vs. broadband sounds, and may be more prominent in the slowly varying fluctuations in sound ("temporal envelope") than in the rapidly varying "fine-structure." Specific Aim 1 is to quantify the effects of permanent noise-induced hearing loss on temporal coding in the ventral cochlear nucleus, which is the first processing station of the ascending auditory brainstem pathway and an obligatory synapse of all auditory-nerve fibers. The balance of fine-structure/envelope strength and tonotopicity will be measured from responses to broadband noise recorded from single neurons in the ventral cochlear nucleus of anesthetized chinchillas. Neurometric analyses will quantify the effects of hearing loss on envelope modulation detection and discrimination thresholds, vs. modulation depth and background-noise level. Specific Aim 2 is to quantify the effects of synaptopathy following temporary threshold shift on auditory-nerve and ventral-cochlear- nucleus responses. Immunohistochemical techniques will be used to quantify synaptopathy and to evaluate sensitivity of non-invasive physiological assays to cochlear-synapse loss. The same single-neuron measures as in Aim 1 will be made for both synaptopathic and non-synaptopathic noise exposures. Specific Aim 3 is to relate behavioral and physiological consequences of noise exposure. Chinchillas will be trained to perform detection and discrimination tasks in background noise. Tone detection, intensity discrimination, and envelope modulation detection and discrimination will be measured. Psychometric (Aim 3) and neurometric (Aims 1 and 2) thresholds will be compared. We hypothesize that hair-cell dysfunction and cochlear synaptopathy will alter envelope more than fine-structure coding, and that this imbalance in temporal coding will be perceptually relevant at low modulation depths associated with listening in noise. No matter whether this hypothesis is supported or refuted, these fundamental data will be extremely useful for linking physiological and perceptual effects of sensorineural hearing loss. By closely coordinating these behavioral and physiological measures with collaborators studying human perceptual deficits after noise exposure, we maximize the potential for translating our animal results to diagnostic and prevalence measures of hidden hearing loss in humans.

描述（由申请人提供）：感官听力损失的重要感知和生理方面（SNHL）仍然“隐藏”标准的临床诊断（即纯音调听力测定法），从而衡量了静静的耳朵敏感性）。时间处理中的距离缺陷在许多带有SNHL的听众中也发生，即使在具有正常听觉阈值的频率下也是如此。此外，在“仅”仅体验暂时的阈值移动的噪声暴露的耳朵中，可能会发生明显的永久人工耳蜗突触病（最高50％）。当前的建议提供了一种系统的方法，可以直接将噪声引起的听力损失的生理和行为效应联系起来。这些实验是基于听觉神经的证据而设计的，表明由于SNHL引起的时间编码的生理缺陷可能在安静的条件下隐藏，对于窄带与宽带声音可能有所不同，并且在声音中缓慢变化的波动可能更为突出（ “暂时信封”）比快速变化的“精细结构”。具体目的1是量化永久噪声引起的听力损失对腹侧耳蜗核中时间编码的影响，腹侧耳蜗核是上升听觉脑干途径的第一个处理站，并且是所有听觉神经纤维的强制性突触。优基结构/包膜强度和体点的平衡将以对麻醉龙骨的腹侧耳蜗核中记录的宽带噪声的响应来测量。神经学分析将量化听力损失对包膜调制检测和歧视阈值，与调制深度和背景噪声水平的影响。具体目的2是量化暂时阈值转移后突触病的影响对听觉障碍和腹侧核核反应的影响。免疫组织化学技术将用于量化突触病，并评估非侵入性生理测定对人工耳蜗损失损失的敏感性。与AIM 1相同的单神经元措施将对突触病变和非突触性噪声暴露进行。具体目的3是将噪声暴露的行为和生理后果联系起来。龙猫将接受训练，以执行背景噪声中的检测和歧视任务。将测量音调检测，强度歧视和信封调制检测和歧视。将比较心理测量学（AIM 3）和神经学（目标1和2）阈值。我们假设发型功能障碍和人工耳蜗突触病比精细结构编码更改包络，并且时间编码中的这种不平衡将在与噪声聆听相关的低调制深度上感知相关。无论是支持还是驳斥了该假设，这些基本数据都将非常有用，可将感觉神经性听力损失的生理和感知效应联系起来。通过与研究噪声暴露后的人类感知缺陷的合作者密切协调这些行为和生理措施，我们最大程度地将动物结果转化为人类隐藏听力损失的诊断和患病率指标。