Biomechanical Measurement and Modeling of Normal and Diseased Middle Ears

描述（由申请人提供）：中耳由听小骨和软组织（包括鼓膜、韧带和关节）组成，在声音传输和听觉中起着至关重要的作用。软组织的力学性质在中耳炎等中耳疾病中发生变化。结果，听骨链的活动性降低，中耳炎耳朵中发生显著的传导性听力损失。然而，与疾病相关的软组织的机械性能变化在很大程度上未被研究。基于当前的临床工具，几乎不可能识别与听力损失相关的中耳组织的机械变化。 该项目的目标是表征正常和患病耳中软组织的生物力学行为，识别与正常听力变化相关的软组织变化，并提供改进的三维（3D）耳模型，以可视化和量化各种疾病中的结构-功能关系。中耳炎（OM）将是该项目的主要重点。目的1：明确中耳软组织在OM中的力学特性变化。我们推测，OM中耳组织的机械性能的变化与组织响应于OM的流体、压力和持续时间的形态学变化有关。本研究将利用动态力学分析仪、分离式霍普金森拉杆、激光多普勒振动仪（LDV）声驱动、条纹云纹系统和软组织有限元建模等方法，对毛丝鼠正常耳和病变耳组织的测量结果进行比较，验证这一假设。目的2：量化中耳生物力学变化对OM声传输的影响。假设OM中的听力损失是由中耳中的耳组织、液体和压力的变化的组合引起的。本研究将通过测量灰鼠OM耳的ABR阈值、中耳传递函数和声能传输的变化来验证这一假设，并借助灰鼠OM耳的有限元模型，对灰鼠OM耳的流体、压力和组织特性进行新的理论分析，以描述OM的发生机制。目标3：继续开发具有临床相关应用的人耳三维有限元模型。我们将在目标1和2中确定组织特性的模型中纳入TM和ISJ的显微结构以及镫骨肌功能。建立了小儿耳的有限元模型，用于研究幼儿的OM。将通过4条新的模型衍生“听觉测试曲线”在3D FE模型中可视化和量化患病耳中通过中耳的声-机械振动和能量传输，这些曲线被命名为：中耳传递函数（METF）、能量吸收（EA）、导纳鼓室图（AT）和TM全息图，这将帮助医生和听力学家解释诊断测试结果并识别中耳疾病的具体类型。 公共卫生相关性：中耳疾病常导致中耳结构和软组织性质的改变，导致传导性听力损失。了解中耳结构改变与中耳功能的关系有助于不同中耳疾病的诊断。拟议的研究项目是确定与中耳疾病相关的耳组织的机械性能变化，并提供一个人耳的计算模型，以可视化和量化各种疾病的结构-功能关系。

DESCRIPTION (provided by applicant): The middle ear, composed of ossicles and soft tissues including the tympanic membrane, ligaments, and joints plays a vital role in the transmission of sound and the sense of hearing. The mechanical properties of soft tissues change in middle ear diseases such as otitis media. As a consequence, the mobility of ossicular chain is reduced and significant conductive hearing loss occurs in otitis media ears. However, the mechanical property changes in soft tissue associated with disease are largely unstudied. It is almost impossible to identify mechanical changes of middle ear tissues in relation to hearing loss based on current clinical tools. The goal of this project is to characterize the biomechanical behaviors of soft tissues in normal and diseased ears, identify soft tissue changes which are associated with changes in normal hearing, and provide an improved 3-dimensional (3D) ear model to visualize and quantify structure-function relations in various diseases. Otitis media (OM) will be the primary focus for the project. Three specific aims are proposed: Aim 1: To Identify changes of mechanical properties of middle ear soft tissue in OM. We hypothesize that the change of mechanical properties of ear tissues in OM is related to morphological changes of the tissue in response to fluid, pressure, and duration of the OM. This hypothesis will be tested by comparison of measurement results of the ear tissues between normal and diseased ears in chinchillas using dynamic mechanical analyzer, split Hopkinson tension bar, acoustic driving with laser Doppler vibrometry (LDV), fringe Moiri system, and FE modeling of soft tissue. Aim 2: To quantify the effect of biomechanical changes of the middle ear on sound transmission in OM. It is hypothesized that the hearing loss in OM is caused by a combination of changes of ear tissues, fluid, and pressure in the middle ear. This hypothesis will be tested by measuring the ABR thresholds and the changes of middle ear transfer function and sound energy transmission in chinchilla OM ears with a novel theoretical analysis of fluid, pressure, and tissue properties with the aid of FE model of chinchilla ear to describe the mechanism of OM. Aim 3: To continue the development of our 3D FE model of the human ear with clinically-relevant applications. We will incorporate into the model with tissue properties determined in Aims 1 and 2, the microstructures of the TM and ISJ, and the stapedius muscle function. A FE model of pediatric ear will be created for studying OM in young children. The acoustic-mechanical vibration and energy transmission through the middle ear in diseased ears will be visualized and quantified in the 3D FE model by 4 novel model-derived "auditory test curves", named as: the middle ear transfer function (METF), energy absorbance (EA), admittance tympanogram (AT), and TM holography, which will assist physicians and audiologists to interpret the diagnostic test results and identify the specific type of middle ear disorders. PUBLIC HEALTH RELEVANCE: Middle ear diseases often result in conductive hearing loss due to the changes of middle ear structure and soft tissue properties caused by the diseases. Understanding the relationship between the middle ear structural change and function of the middle ear will help diagnosis of different middle ear diseases. The proposed research project is to determine mechanical property changes in ear tissues associated with middle ear diseases and provide a computational model of the human ear to visualize and quantify structure-function relations in various diseases.