Middle-ear Mechanics in Normal and Pathological Ears

这项工作的目的是了解声音通过正常、病变和重建的中耳传播，以便为中耳疾病患者提供更好的诊断测试和手术治疗。在美国，慢性中耳炎和耳硬化等中耳疾病影响着超过1000万人，是导致传导性听力损失的常见原因。目前的一系列诊断测试（耳镜检查、听力学、鼓室测量）不能可靠地区分听骨病理，特别是当鼓膜完好或先前有中耳手术时。此外，人们普遍认为，慢性中耳炎鼓室成形术后的听力结果往往不令人满意。导致手术结果不佳的因素包括对重建耳的关键结构-功能关系缺乏清晰的认识，以及当前诊断测试无法确定这种关系。激光多普勒测振法在评估中耳功能方面已被证明比测听法和鼓室法更敏感，因为激光光斑（直径仅100微米）可以聚焦在鼓膜和锤骨的各个点上，而且因为测振法不受耳道的影响（不像鼓室法）。我们建议使用振动测量、其他声学测量（导纳和反射率）、听力学和鼓室测量来研究(a)正常耳、(b)伴有听骨病变的患病耳和(c)因慢性中耳炎或耳硬化而接受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手术修饰的人类颞骨准备中进行，以模仿患病和重建的耳朵。我们的方法将有助于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，更好地进行术前患者咨询和手术计划，优化手术技术和听力效果，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.