Human middle-ear imaging, physiology, and biomechanics

人类中耳成像、生理学和生物力学

• 批准号: 8214658
• 负责人: CHARLES Richard STEELE
• 金额: $ 32.42万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-02-17 至 2014-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8214658
• 关键词: 3-Dimensional; Acoustics; Affect; Air; Animals; Biomechanics; Bone Conduction; Cartilage; Characteristics; Clinical; Cochlea; Collagen Fiber; Complex; Computer Simulation; Coupling; Cues; Ear; Electron Microscopy; Elements; Fascia; Fiber; Foundations; Frequencies; Generations; Goals; Grant; Hearing; Human; Image; Incus; Joints; Knowledge; Lasers; Lead; Malleus; Mammals; Measurement; Measures; Methods; Microscopy; Modeling; Motion; Muscle; Myringoplasty; Noise; Operative Surgical Procedures; Optics; Otologic Surgical Procedures; Outcome; Patients; Persons; Physics; Physiological; Physiology; Play; Procedures; Process; Prosthesis; Radial; Research; Role; Shapes; Solid; Sound Localization; Speech; Speech Perception; Stapes; Structure; Structure-Activity Relationship; Surgeon; Temporal bone structure; Testing; Thinking; Transducers; Transmission Electron Microscopy; Tympanic membrane; Tympanoplasty; Vertebrates; base; bone; clinical application; computer framework; cryogenics; ear muscle; expectation; improved; middle ear; morphometry; multi-photon; otoacoustic emission; reconstruction; repaired; research study; response; restoration; second harmonic; sound; sound frequency; stapedius muscle; tensor tympani muscle; transmission process; virtual

DESCRIPTION (provided by applicant): The middle ear plays a vital role in the sense and sensitivity of hearing, yet there is currently a lack of knowledge about the mechanisms of high-frequency middle-ear sound transmission in mammals. The overall goal of this project is to understand the relationships between the morphometry of the middle ear and the biomechanical processes that lead to physiological and clinical responses. The approach is to deconstruct the middle ear into subsystems that are each characterized by morphological and physiological measurements, as well as three-dimensional linear and nonlinear mathematical analyses. The subsystems are then mathematically reassembled to form a complete `virtual middle-ear' model that can be used to examine issues relevant to high frequency sound transmission in a variety of animals and repaired middle ears before and after surgery. Specific Aim #1: At high frequencies, experimental evidence suggests that sound conduction is not limited by the inertia of the middle-ear bones, contrary to expectations. Recent moment of inertia calculations suggest that the malleus switches from a hinging motion at low frequencies to a new twisting motion at high frequencies, in order to take advantage of the reduced inertia associated with a twisting type of motion. It is hypothesized that the mobile saddle-shaped malleus-incus joint is able to suitably transfer this twisting motion to the incus. This will be tested using micro-CT imaging, cryogenic transmission electron microscopy, optical second harmonic generation, hinging and twisting motion measurements with a laser Doppler vibrometer, and bio-computational modeling. Specific Aim #2: The human middle-ear cavity is known to be an irregularly shaped space within the temporal bone that varies from person to person. A finite element modeling approach will be used to test the hypothesis that the complex shape of the human middle-ear cavity functions to break up resonant modes that would otherwise decrease hearing sensitivity at specific resonant frequencies. The finite element approach, which is well-suited for the nonlinear descriptions needed to incorporate the forces exerted by the tensor tympani and the stapedius muscles, will also be used to understand how these muscles affect sound transmission through the middle ear. Specific Aim #3: Ear surgeons target restoration of hearing in the speech frequency range, and not in the higher frequencies where important sound localization cues are known to reside. Temporal bone measurements and the anatomically- and physics-based virtual middle-ear model will be used to understand how to improve high-frequency outcomes of middle-ear surgical treatments, such as tympanic membrane repair (myringoplasty) and ossicle replacement with a prosthesis (tympanoplasty). Specific Aim #4: Our hypothesis that myringoplasty and tympanoplasty surgery patients continue to have air-bone gap deficits at frequencies above 4 kHz will be tested. New methods to measure bone conduction sensitivity will be developed for high frequencies and combined with existing air conduction measurement methods. While it is well accepted that amongst terrestrial vertebrates, the mammalian middle ear is unique in its ability to transmit sounds from the external world to the cochlea for frequencies above 10 kHz, the biomechanical basis for sound transmission at high frequencies is poorly understood, which has consequences in the clinical realm. It is well known that the morphometry of the middle ear plays a key role in sound transmission, but the lack of knowledge about the relationships between middle-ear structures and sound transmission has resulted in unsatisfactory and variable outcomes of middle-ear repairs, particularly at high frequencies where sound localization cues may be important for hearing in noisy situations. The proposed studies will provide a solid scientific foundation for understanding the structural basis of middle-ear sound transmission, leading to clinical applications for the surgical reconstruction of the middle ear, the interpretation of otoacoustic emissions, and improvements to the understanding of passive and active prostheses used by surgeons to repair the middle ear.

描述(申请人提供)：中耳在听觉的感觉和敏感度方面起着至关重要的作用，但目前对哺乳动物高频中耳声音传播的机制缺乏了解。这个项目的总体目标是了解中耳的形态测量和导致生理和临床反应的生物力学过程之间的关系。方法是将中耳分解成各个子系统，每个子系统都以形态和生理测量以及三维线性和非线性数学分析为特征。然后，这些子系统在数学上重新组装，形成一个完整的“虚拟中耳”模型，该模型可以用来检查与各种动物和手术前后修复的中耳相关的高频声音传播问题。具体目标1：在高频下，实验证据表明，声音传导并不受中耳骨惯性的限制，这与预期相反。最近的转动惯量计算表明，锤骨在低频下从铰链运动切换到高频下的新的扭转运动，以便利用与扭转类型的运动相关的减小的惯性。据推测，活动的马鞍形锤骨关节能够适当地将这种扭转运动传递到砧骨。这将使用微型CT成像、低温透射电子显微镜、光学二次谐波产生、激光多普勒振动计的铰链和扭转运动测量以及生物计算模型来进行测试。具体目标#2：众所周知，人的中耳腔是颞骨内的一个形状不规则的空间，因人而异。有限元建模方法将被用来检验这样一个假设，即人类中耳腔的复杂形状起到了分解共振模式的作用，否则这些共振模式会在特定的共振频率下降低听力敏感度。有限元方法非常适合于非线性描述，需要结合鼓膜张肌和腓骨肌施加的力，也将被用来理解这些肌肉如何影响通过中耳的声音传输。具体目标#3：耳外科医生的目标是在语音频率范围内恢复听力，而不是在已知存在重要声音定位线索的较高频率上。将使用颞骨测量以及基于解剖学和物理学的虚拟中耳模型来了解如何改善中耳手术治疗的高频结果，例如鼓膜修复(鼓膜成形术)和假体听骨置换(鼓室成形术)。具体目标#4：我们假设鼓膜成形术和鼓室成形术患者在频率高于4 kHz时仍有气骨间隙缺陷，这一假设将得到验证。将开发新的高频骨传导灵敏度测量方法，并与现有的空气传导测量方法相结合。虽然众所周知，在陆生脊椎动物中，哺乳动物的中耳在10 kHz以上的频率下将声音从外部世界传递到耳蜗的能力是独一无二的，但人们对高频声音传递的生物力学基础知之甚少，这在临床领域具有重要意义。众所周知，中耳的形态测量在声音传播中起着关键作用，但由于缺乏对中耳结构和声音传播之间关系的了解，导致中耳修复的结果不令人满意和可变，特别是在高频情况下，声音定位线索可能对噪声环境下的听力至关重要。这些研究将为理解中耳声传播的结构基础提供坚实的科学基础，为中耳外科重建、耳声发射的解释以及提高外科医生用于修复中耳的被动和主动假体的理解提供临床应用。