Biomechanical Measurement and Modeling of Normal and Diseased Middle Ears

描述(申请人提供)：中耳由听小骨和软组织组成，包括鼓膜、韧带和关节，在声音和听觉的传递中起着至关重要的作用。软组织的力学性质在中耳疾病如中耳炎时会发生变化。其结果是，听骨链的活动度降低，中耳炎患者出现显著的传导性听力损失。然而，软组织中与疾病相关的力学性质的变化在很大程度上还没有被研究。根据目前的临床工具，几乎不可能识别与听力损失有关的中耳组织的机械变化。该项目的目的是描述正常和疾病耳朵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，并提供一种改进的三维(3D)耳朵模型，以可视化和量化各种疾病的结构-功能关系。中耳炎(OM)将是该项目的主要焦点。目的1：明确OM患者中耳软组织力学性质的变化。我们假设OM时耳部组织力学性质的改变与组织对液体、压力和OM持续时间的形态变化有关。这一假设将通过动态力学分析仪、分离式Hopkinson张力杆、激光多普勒振动(LDV)声驱动、条纹Moiri系统和软组织有限元模型对龙猫正常耳朵和患病耳朵组织的测量结果进行比较来验证。目的：定量研究中耳生物力学变化对OM声音传播的影响。据推测，OM的听力损失是由耳组织、耳液和中耳压力的变化共同引起的。这一假说将通过测量栗鼠OM耳的ABR阈值以及中耳传递函数和声能量传递的变化来验证，该理论分析了流体、压力和组织特性，并借助于龙猫耳朵的有限元模型来描述OM的机制。目的3：继续开发我们的人耳三维有限元模型，并将其应用于临床。我们将在模型中加入目标1和目标2中确定的组织特性、TM和ISJ的微观结构以及腓骨肌功能。本研究将建立儿童耳的有限元模型，用于儿童OM的研究。在三维有限元模型中，通过4种新的模型导出的“听觉测试曲线”，即中耳传递函数(METF)、能量吸收(EA)、导纳鼓室图(AT)和TM全息术，将病变耳朵的声-机械振动和能量传递可视化和量化，这将帮助医生和听力专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：中耳疾病往往会引起中耳结构和软组织特性的改变，从而导致传导性听力损失。了解中耳结构变化与中耳功能的关系，有助于不同中耳疾病的诊断。提出的研究项目是确定与中耳疾病相关的耳朵组织的力学性质变化，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.