Middle-ear Mechanics in Normal and Pathological Ears

这项工作的目的是了解声音通过正常中耳、病变中耳和再造中耳的传播，以便为中耳疾病患者提供更好的诊断测试和手术程序。中耳疾病，如慢性中耳炎和耳硬化症，在美国影响着1000多万人，是导致重大传导性听力损失的常见原因。目前的一系列诊断试验(耳镜、测听、鼓室导纳)不能可靠地鉴别听小骨病变，特别是在鼓膜完整或有中耳手术的情况下。此外，人们普遍认为，慢性中耳炎鼓室成形术后的听力效果往往不令人满意。导致手术结果一般的因素包括对再造耳的关键结构-功能关系缺乏清楚的了解，以及目前的诊断测试未能确定这种关系。激光多普勒测振已被证明在评估中耳功能方面比测听和鼓室导纳更敏感，因为激光斑点(直径只有100微米)可以聚焦在鼓膜和锤部的不同点上，而且测振不受耳道的影响(与鼓室测压不同)。我们建议使用振动测量、其他声学测量(导纳和反射)、听力测量和鼓室导纳测量来研究(A)正常耳、(B)听小骨病变病变耳和(C)接受慢性中耳炎或耳硬化症手术的重建耳的结构-功能关系。类似的振动测量和声学测量也将在一种经过手术修改的人类颞骨准备中进行，这种准备模仿患病和重建的耳朵。我们的方法将导致更好地了解正常和病理中耳的结构-功能关系，改进中耳病变的鉴别诊断，更好地术前患者咨询和手术计划，优化手术技术和听力结果，并减少手术失败的数量。

The goal of this work is to understand sound transmission through normal, diseased and reconstructed middle ears so that better diagnostic tests and surgical procedures can be offered to patients with middle-ear disease. Middle-ear diseases such as chronic otitis media and otosclerosis, which affect over 10 million people in the US, are common causes of significant conductive hearing loss. The current battery of diagnostic tests (otoscopy, audiometry, tympanometry) cannot reliably differentiate ossicular pathology, especially when the tympanic membrane is intact or if there has been prior middle-ear surgery. Additionally, it is commonly acknowledged that post- operative hearing results after tympanoplasty procedures for chronic otitis media are often unsatisfactory. Factors contributing to the modest nature of surgical results include lack of clear understanding of the critical structure-function relationships in the reconstructed ear, and failure of current diagnostic tests to determine such relationships. Laser Doppler vibrometry has been demonstrated to be more sensitive than audiometry and tympanometry in assessing middle- ear function, because the laser spot (only 100 micrometers diameter) can be focused at various points on the tympanic membrane and malleus, and because vibrometry is unaffected by the ear canal (unlike tympanometry). We propose to use vibrometry, other acoustical measurements (admittance and reflectance), audiometry and tympanometry to investigate structure-function relationships in (a) normal ears, (b) diseased ears with ossicular pathologies, and (c) reconstructed ears that have undergone surgery for chronic otitis media or otosclerosis. Similar vibrometry and acoustical measurements will also be made in a surgically-modified human temporal bone preparation that mimics diseased and reconstructed ears. Our approach should lead to a better understanding of the structure-function relationships in normal and pathological middle ears, improved differential diagnosis of middle-ear lesions, better pre-operative patient counseling and surgical planning, optimization of surgical techniques and hearing results, and reduction in the number of failed surgeries.