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

描述(申请人提供)：许多患者患有传导性听力损失(CHL)，尽管他们的神经感觉系统完好无损，但难以治疗。圆窗(RW)和骨传导(BC)刺激已被证明可以改善各种治疗失败的CHL的听力。然而，这些替代的刺激方法收效甚微。由于缺乏对通过这些刺激方法将声音传递到耳蜗区的独特机制的了解，以及它们的应用方式的限制，它们的应用受到阻碍。新鲜的人体身体标本可以进行可控的侵入性实验，以阐明这些机制，模拟各种传导性疾病，评估和改进设备和治疗方法。使用我们的新技术测量耳廓内压力，我们可以更好地了解这些不同于正常空气传导声音刺激的替代声刺激途径的机制。此外，差压刺激Dp的确定允许在正常刺激和替代刺激期间以及在内耳阻抗改变的疾病条件下，如上半规管裂开(SCD)，监测到耳蜗的输入。我们使用这项技术来回答以前无法解决的问题：目的1)评估和改进刺激RW的方法。用粗略修改的中耳植入物进行RW刺激已经帮助了许多CHL患者，而这些患者并没有通过其他方式得到帮助。然而，听证结果各不相同。我们将开发一种针对RW的独特解剖和力学特性的RW刺激“耦合系统”。该系统将提供更安全、更有效和一致的RW刺激。通过在人体身体制剂的受控环境中测量DP，我们的耦合系统的性能将与其他RW刺激耦合方法进行定量比较，并将确定安全、高效、一致性和易于手术实施的关键特征。此外，还将确定优化RW执行器性能所需的机械规格。目的2)阐明BC对耳部刺激的作用机制，明确BC在不同病理条件下的作用机制。BC刺激被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刺激的机制尚不清楚。我们将通过测量人体身体标本中BC刺激诱发的卵泡内压差(DP)来促进对BC及其影响的理解。本研究将：1)确定听小骨运动和耳蜗液的惯性效应以及周围骨的压缩效应对BC的贡献；2)确定BC刺激方向的影响；3)确定SCD对BC的影响。BC诱发的DP的测定将有助于阐明BC的发病机制，促进BC在诊断和治疗中的应用。

DESCRIPTION (provided by applicant): 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.