HUMAN MIDDLE EAR--FORWARD AND REVERSE SOUND TRANSMISSION

该项目旨在表征正向和反向声音 通过人的中耳传播。一个最 在过去的二十年里，听力方面的重大发现 一个健康的耳朵不仅能感知声音， 声音.这种“反向能量流”起源于耳蜗， 通过中耳传播，并可测量为耳声 耳道中的放射物。耳声的可及性 排放量测量使他们成为一个潜在的有用工具， 客观评价耳蜗和中耳功能。然而，在这方面， 关于中耳对耳声的影响知之甚少 因此，我们对内耳的看法受到了干扰 对中耳的不完全了解。理解如何 中耳影响正向和反向声音传输， 测量将在具体修改之前和之后进行 到人尸体的中耳测量将包括 从耳道到内耳的中耳压力增益 （前向压力增益），来自内耳的中耳压力增益 耳道（反向压力增益），中耳输入 阻抗和耳道压力到镫骨的速度传递。 中耳修改的例子包括固定镫骨 (as耳硬化症），固定锤骨头，和 鼓膜穿孔这些测量将用于开发 正常人中耳的数学模型， 病理条件。为了测试 数学模型，以正常和病理的活体 中耳，气孔间隙和耳声发射将是 在人类受试者中测量。对受试者的测量将 与数学模型的结果进行了比较。这些比较 旨在测试数学模型的适用性 并让我们能够设计出去除 中耳的混杂效应， 耳声发射，从而增加了一般效用 耳声发射作为检测耳蜗的诊断工具 功能障碍

This project seeks to characterize forward and reverse sound transmission through the human middle ear. One of the most significant discoveries in hearing during the past twenty years has been that a healthy ear not only detects sound but also generates sounds. This "reverse energy flow" originates in the cochlea, travels through the middle ear and can be measured as otoacoustic emissions in the ear canal. The accessibility of otoacoustic emissions to measurements makes them a potentially useful tool for objective evaluation of cochlear and middle-ear function. However, little is known about the effect of the middle ear on otoacoustic emissions and thus our view of the inner ear is clouded by incomplete knowledge of the middle ear. To understand how the middle ear affects forward and reverse sound transmission, measurements will be made before and after specific modifications to the middle ears of human cadavers. Measurements will include middle-ear pressure gain from the ear canal to the inner ear (forward pressure gain), middle-ear pressure gain from the inner ear to the ear canal (reverse pressure gain), middle-ear input impedance, and ear-canal pressure to stapes-velocity transmission. Examples of middle-ear modifications include fixation of the stapes (as in otosclerosis), fixation of the incus-malleus head, and eardrum perforations. These measurements will be used to develop mathematical models of the human middle ear for normal and pathological conditions. To test the applicability of the mathematical models to living subjects with normal and pathological middle ears, air-hone gap and otoacoustic emissions will be measured in human subjects. Measurements on subjects will be compared with results of the mathematical models. These comparisons are intended to test the applicability of the mathematical models to living humans and to allow us to devise ways to remove the confounding effects of the middle ear from measurements of otoacoustic emissions and thus increase the general utility of otoacoustic emissions as a diagnostic tool for detecting cochlear dysfunction.