DEVELOPMENT OF HUMAN COCHLEAR FUNCTION

描述：这个项目的长期目标是调查 人类耳蜗机能的发展。这一谅解将提供一种 更准确地识别耳蜗性功能障碍的框架，提供 支持听力假体的开发和改进，并做出贡献 关于人类听觉发育的一般理论。长期目标将是 通过研究时间过程和频率相关性来实现 发展(1)耳蜗调谐，(2)主动耳蜗力学，和(3) 应用失真产物耳声发射检测耳蜗声传出功能 (DPOAE)方法。DPOAE是由DPOAE产生的互调产品 当同时呈现两个音调(f1，f2)时，耳蜗声正常。 它们提供了一种非侵入性的、频率特定的耳蜗生理学探头 在人类身上。 本课题包括三个实验：1)实验一，DPOAE 同侧抑制调谐曲线将提供间接测量 29~36周胎龄新生儿的耳蜗调优， 足月儿和听力正常的成人受试者在五个f2频率： 1100、2500、5600、9000和12,500赫兹。抑制调谐曲线将是 用低级别原音录制，以包含活动的影响 耳蜗力学和高水平原音，以最大限度地减少对 积极的人工耳蜗机。调整曲线宽度、斜率和尖端的措施 将分析年龄、频率和水平差异的特征； 2)在实验2中，DPOAE增长函数(DPOAE幅度作为以下函数 主音电平)将被生成作为活动耳蜗量的测量 人类新生儿的机械性活动或耳蜗放大活动 发育阶段和f2频率在实验中的应用1.DPOAE 生长函数形状、斜率和缺口阈值(幅度平台水平 或减少)将分析年龄和频率差异；3) 实验3，将测量对侧DPOAE抑制作为一项指标 新生儿内侧橄榄耳蜗传出功能的研究 实验1和实验2中应用的发育阶段和f2频率。 DPOAE增长函数将在有和没有宽带噪声的情况下记录 呈现给另一只耳朵。平均噪声和无噪声之间的差异 将测试噪声条件，以检测对侧DPOAE抑制。 对侧DPOAE抑制将分析年龄、频率和 关卡效果。除了调查独立开发的 耳蜗调谐，主动耳蜗力学和传出功能，这些 研究将阐明这三个方面之间的关系 人类成熟过程中的耳蜗生理学。

DESCRIPTION: The long-term goal of this project is to investigate the development of human cochlear function. This understanding will provide a framework for more precise identification of cochlear dysfunction, provide support for development and refinement of auditory prostheses and contribute t general theory on human auditory development. The long-term goal will be accomplished by investigating the timecourse and frequency dependent development of (1) cochlear tuning, (2) active cochlear mechanics, and (3) cochlear efferent function using distortion product otoacoustic emission (DPOAE) methodology. DPOAEs are intermodulation products generated by the normal cochlea when it is presented with two tones (f1, f2) simultaneously. They provide a noninvasive, frequency-specific probe of cochlear physiology in humans. This project includes three experiments: 1) In Experiment 1, DPOAE ipsilateral suppression tuning curves will provide an indirect measure of cochlear tuning in neonates ranging from 29 to 36 weeks conceptional age, term infants and normal-hearing adult subjects at five f2 frequencies: 1100, 2500, 5600, 9000 and 12,500 Hz. Suppression tuning curves will be recorded with low-level primary tones to include influence of active cochlear mechanics, and high-leve primary tones to minimize contribution of active cochlear mechanics. Measures of tuning curve width, slope and tip characteristics will be analyzed for age, frequency, and level differences; 2) In Experiment 2, DPOAE growth functions (DPOAE amplitude as a function of primary tone level) will be generated as a measure of active cochlear mechanics or cochlear amplifier activity in human neonates at the same developmental stages and f2 frequencies applied in Experiment 1. DPOAE growth function shape, slope and notch threshold (level of amplitude plateau or decrease) will be analyzed for age and frequency differences; 3) in Experiment 3, contralateral DPOAE suppression will be measured as an index of medial olivocochlear efferent function in human neonates at the same developmental stages and f2 frequencies applied in Experiments 1 and 2. DPOAE growth functions will be recorded with and without broadband noise presented to the opposite ear. The difference between average noise and no noise conditions will be tested to detect contralateral DPOAE suppression. Contralateral DPOAE suppression will be analyzed for age, frequency and level effects. In addition to investigating the independent development of cochlear tuning, active cochlear mechanics and efferent function, these studies will elucidate the relationship among these three aspects of cochlear physiology during human maturation.