How does the efferent auditory system function in the neural encoding and perception of speech-in-noise?

传出听觉系统在噪声中语音的神经编码和感知中如何发挥作用？

• 批准号: 8833717
• 负责人: Spencer Smith
• 金额: $ 3.96万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-20 至 2017-08-19
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8833717
• 关键词: Academic achievement; Acoustic Nerve; Action Potentials; Address; Adult; Affect; Aging; Algorithms; Animal Experimentation; Animals; Auditory; Auditory Brainstem Responses; Auditory Perception; Auditory system; Biological Assay; Brain; Brain Stem; Child; Cochlea; Cochlear Implants; Code; Cognitive; Consensus; Contralateral; Data; Ear; Evaluation; External auditory canal; Feedback; Functional disorder; Goals; Hearing; Hearing Aids; Human; Impairment; Individual; Labyrinth; Language; Lead; Learning Disorders; Left; Masks; Measurement; Measures; Mechanics; Medial; Modeling; Nervous system structure; Neurobiology; Noise; Outcomes Research; Output; Participant; Patients; Perception; Physiological; Process; Reading; Recruitment Activity; Reflex action; Research; Role; Signal Transduction; Site; Speech; Speech Perception; Structure of tractus olivocochlearis; System; Time; Withdrawal; Work; base; disability; experience; improved; nerve supply; neural circuit; noise perception; otoacoustic emission; public health relevance; relating to nervous system; research study; response; social; speech processing

DESCRIPTION (provided by applicant): Severe difficulty understanding speech-in-noise causes social withdrawal, inhibits academic achievement, and limits vocational opportunities for those affected. Inexplicably, there are individuals who experience severe difficulty understanding speech-in-noise despite having normal hearing sensitivity, such as normally aging adults and children with reading, language, auditory processing, and learning disorders. The neurobiological basis of speech-in-noise deficits in these individuals is currently unknown, which limits evaluation and targeted treatment of this hearing disability. The efferent auditory system is the division of the auditory nervous system that is believed to fine-tune and filter auditory information as it ascends from the inner ears to the brain. This system has been studied extensively in animals, but far less is known about how it works in humans during speech-in-noise processing. Some evidence suggests that selective dysfunction in the efferent auditory system may cause severe difficulty hearing in noise while leaving hearing sensitivity intact. The proposed research investigates the function of one specific mechanism of the human efferent auditory system, the medial olivocochlear (MOC) bundle, in the neural encoding and perception of speech-in-noise in normal hearing adults and children. The MOC bundle is an efferent neural circuit, which has been shown to filter and suppresses background noise at the level of the inner ear in animals. This filter may allow less noise to be transcribed into neural code, which in turn improves perception of auditory signals in competing background noise. It remains unclear if the human MOC reflex is: a) an important efferent mechanism that reduces the effect of noise on the bottom-up neural encoding of speech, and b) modulated by top-down processes, such as active listening, to enhance hearing in noise. These issues will be addressed in two studies. The first study will involve measurements of speech-evoked neural activity from the auditory nerve and brainstem during MOC reflex activation to determine if this reflex improves the neural encoding of speech-in-noise. It is hypothesized that activation of the MOC reflex will improve the neural encoding of speech-in-noise at the level of the auditory nerve and brainstem. In the second study, participants will actively listen to an Auditory Stroop Task while the MOC reflex is engaged to determine if cognitive demands modulate the MOC reflex. It is hypothesized that more challenging listening conditions of the Auditory Stroop Task will have a greater impact on MOC reflex strength, indicating a modulatory relationship between the brain and inner ears. The outcomes of this research clarify the role of the efferent system in speech-in-noise processing and can be used to create targeted treatments and objective assessments for individuals with severe difficulties understanding speech-in-noise.

描述（由申请人提供）：严重困难的理解语音噪音导致社会退缩，抑制学术成就，并限制受影响者的职业机会。令人费解的是，有些人尽管具有正常的听力敏感度，但仍然难以理解噪声中的语音，例如正常老化的成年人和患有阅读、语言、听觉处理和学习障碍的儿童。目前尚不清楚这些人噪声中言语缺陷的神经生物学基础，这限制了对这种听力残疾的评估和针对性治疗。 传出听觉系统是听觉神经系统的一个分支，被认为在听觉信息从内耳上升到大脑时对听觉信息进行微调和过滤。这个系统已经在动物身上进行了广泛的研究，但对于它在人类中如何在噪声中处理语音的过程中发挥作用却知之甚少。一些证据表明，传出听觉系统的选择性功能障碍可能会导致在噪声中听力严重困难，而保持听力敏感性不变。 拟议的研究探讨了人类传出听觉系统的一个特定机制，内侧橄榄耳蜗（MOC）束，在正常听力成人和儿童的噪声中的语音的神经编码和感知的功能。MOC束是传出神经回路，其已被证明在动物的内耳水平过滤和抑制背景噪声。该滤波器可以允许较少的噪声被转录成神经代码，这进而改善了在竞争背景噪声中对听觉信号的感知。目前尚不清楚人类的MOC反射是否是：a）一种重要的传出机制，可以减少噪音对自下而上的语音神经编码的影响，以及B）由自上而下的过程（如主动倾听）调制，以增强噪音中的听力。 这些问题将在两项研究中讨论。第一项研究将涉及在MOC反射激活期间测量听神经和脑干的语音诱发神经活动，以确定该反射是否改善了噪声中语音的神经编码。假设MOC反射的激活将在听神经和脑干水平上改善噪声中语音的神经编码。在第二项研究中，受试者将积极听取听觉Stroop任务，同时进行MOC反射，以确定是否认知需求调节MOC反射。假设更具挑战性的听觉Stroop任务的听力条件将对MOC反射强度产生更大的影响，表明大脑和内耳之间存在调制关系。这项研究的结果阐明了传出系统在噪声中的语音处理中的作用，并可用于为有严重困难理解噪声中的语音的个体创建有针对性的治疗和客观评估。