Human middle-ear imaging, physiology, and biomechanics

人类中耳成像、生理学和生物力学

• 批准号: 7850313
• 负责人: CHARLES Richard STEELE
• 金额: $ 26.18万
• 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: 2009-07-17 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7850313
• 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（由申请人提供）：中耳在听觉的感觉和灵敏度中起着至关重要的作用，但目前缺乏关于哺乳动物中高频中耳声音传输机制的知识。本项目的总体目标是了解中耳形态测量学与导致生理和临床反应的生物力学过程之间的关系。该方法是将中耳解构成子系统，每个子系统的特征在于形态和生理测量，以及三维线性和非线性数学分析。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，可用于检查各种动物的高频声音传输相关问题，并在手术前后修复中耳。具体目标1：在高频下，实验证据表明声音传导不受中耳骨惯性的限制，这与预期相反。最近的惯性矩计算表明，锤骨从低频率的铰链运动切换到高频率的新的扭转运动，以利用与扭转类型的运动相关的减小的惯性。据推测，移动的鞍形锤骨-砧骨关节能够适当地将这种扭转运动传递到锤骨。这将使用微CT成像，低温透射电子显微镜，光学二次谐波产生，铰链和扭转运动测量与激光多普勒测振仪，和生物计算建模进行测试。具体目标#2：众所周知，人类中耳腔是颞骨内形状不规则的空间，因人而异。将使用有限元建模方法来检验假设，即人类中耳腔的复杂形状用于破坏共振模式，否则共振模式将降低特定共振频率下的听力灵敏度。有限元方法，这是非常适合的非线性描述所需的纳入由鼓膜张肌和镫骨肌施加的力，也将被用来了解这些肌肉如何影响声音通过中耳传输。具体目标#3：耳外科医生的目标是恢复语音频率范围内的听力，而不是已知存在重要声音定位线索的较高频率。颞骨测量和基于解剖学和物理学的虚拟中耳模型将用于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）和用假体进行听骨置换（鼓膜成形术）。具体目标#4：我们的假设，鼓膜成形术和鼓室成形术手术患者继续有气骨间隙赤字在4 kHz以上的频率将进行测试。新的方法来测量骨传导灵敏度将开发高频率，并结合现有的空气传导测量方法。虽然公认的是，在陆生脊椎动物中，哺乳动物中耳在将频率高于10 kHz的声音从外部世界传输到耳蜗的能力方面是独特的，但对高频声音传输的生物力学基础知之甚少，这在临床领域中具有后果。众所周知，中耳的形态测量在声音传输中起着关键作用，但是缺乏关于中耳结构与声音传输之间的关系的知识导致中耳修复的结果不令人满意且可变，特别是在声音定位线索对于噪声情况下的听力可能很重要的高频下。拟议的研究将为理解中耳声音传输的结构基础提供坚实的科学基础，从而导致中耳手术重建的临床应用，耳声发射的解释，以及改善对外科医生用于修复中耳的被动和主动假体的理解。