Mechanics of Human Middle & Inner Ear: Basic Science & Clinical Application

项目总结/摘要 许多患者患有传导性听力损失（CHL），这是难以治疗的，尽管他们 神经感觉系统完好无损圆窗（RW）和骨传导（BC）刺激已被证实 为各种治疗失败的CHL提供改善的听力。然而，这些替代 刺激方法的成功有限。它们的应用受到阻碍，因为缺乏对 通过这些刺激方法将声音传输到耳蜗分区的独特机制，以及 限制其应用的方式。新鲜人尸体制备物允许受控 侵入性实验，以阐明这些机制，模拟各种传导性疾病，并评估和 改进设备和治疗。利用我们新的颅内压测量技术，我们可以 更好地理解这些替代声音刺激途径的机制，这些途径与 正常的空气传导声音刺激。此外，压差刺激的确定， DP允许在正常和交替刺激期间以及在疾病中监测耳蜗的输入 内耳阻抗改变的情况，如上级半规管裂开（SCD）。 我们采用这种技术来回答以前无法解决的问题：目标1）评估和 改进刺激RW的方法。用粗糙的中耳植入物进行RW刺激， 帮助了许多其他方法无法帮助的CHL患者。然而，听力结果各不相同。 我们将开发一种用于RW刺激的“耦合系统”，该系统针对独特的解剖结构， RW的机械性能。该系统将提供更安全、更有效和一致的RW刺激。 通过在人尸体制备的受控环境中测量DP，我们的性能 耦合系统将定量地与其他RW刺激耦合方法进行比较，并且关键 将确定手术实施的安全性、效率、一致性和容易性的特征。 此外，优化RW致动器性能所需的机械规格将是 测定目的2）阐明BC刺激耳的机制，并确定BC是如何刺激耳的。 受到不同病理的影响。BC刺激用于诊断感觉神经性听力损失和治疗 传导性和混合性听力损失，但BC刺激的机制还没有很好地理解。我们将 通过测量颅内压差、DP、诱发电位， 通过人体尸体标本中的BC刺激。研究将：1）确定 听骨运动和耳蜗液的惯性效应以及周围骨的压缩效应; 2） 确定BC刺激方向的影响;和3）确定SCD对BC的影响。的 测量BC诱发的DP将阐明BC机制并改进BC诊断的应用 和治疗。

Project Summary/Abstract Many patients suffer from conductive hearing loss (CHL) that is intractable to treatment, although their neurosensory system is intact. Round-window (RW) and bone-conduction (BC) stimulation have been proven to provide improved hearing for CHL that have failed various treatments. However these alternative stimulation methods have limited success. Their application is hindered both by a lack of knowledge of the unique mechanisms by which sound is transmitted to the cochlear partition by these stimulus methods, and limitations in the manner in which they are applied. Fresh human cadaveric preparations allow for controlled invasive experiments to elucidate these mechanisms, simulate various conductive diseases and evaluate and improve devices and treatments. With our new technique of intracochlear pressure measurement, we can better understand the mechanisms of these alternative sound stimulus pathways that differ substantially from normal air-conducted sound stimulation. Furthermore, the determination of the differential pressure stimulus, DP, allows monitoring of the input to the cochlea during normal and alternative stimulation and in disease conditions where the inner-ear impedances are changed, such as superior semicircular canal dehiscence (SCD). We employ this technique to answer questions that could not be previously addressed: Aim 1) Evaluate and improve methods for stimulating the RW. RW stimulation with crudely-modified middle-ear implants has aided numerous patients with CHL that were not helped by other means. However, hearing results have varied. We will develop a "coupling system" for RW stimulation that is specific for the unique anatomy and mechanical properties of the RW. This system will provide safer, more efficient and consistent RW stimulation. By measuring DP in the controlled environment of human cadaveric preparations, the performance of our coupling system will be compared quantitatively to other RW stimulation coupling methods, and critical features for safety, efficiency, consistency and ease of surgical implementation will be ascertained. Furthermore, the mechanical specifications required to optimize performance of a RW actuator will be determined. Aim 2) Elucidate the mechanisms involved in BC stimulation of the ear and determine how BC is affected by different pathologies. BC stimulation is used to diagnose sensory-neural hearing loss and to treat conductive and mixed hearing loss, yet the mechanisms of BC stimulation are not well understood. We will advance the understanding of BC and its effects by measuring intracochlear differential pressure, DP, evoked by BC stimulation in human cadaveric preparations. The study will: 1) Determine the contributions to BC of the inertial effects of ossicular motion and cochlear fluids and the compression effect of surrounding bone; 2) Determine the effects of the direction of BC stimulation; and 3) Determine the effect of SCD on BC. The measurements of BC-evoked DP will elucidate BC mechanisms and improve applications of BC for diagnosis and treatment.