人工听骨不同接入方式对耳结构动力响应的影响

目的 研究人工听骨接入方式对听力恢复的影响。方法 通过CT扫描技术,结合自编C＋＋程序读取CT数据中体单元建立人耳结构几何模型,将几何模型导入PATRAN中建立有限元数值模型。采用频率响应方法对耳结构模型进行流固耦合计算,同时分析人工听骨不同接入方式及接入位置对耳结构声音传导的影响。结果 通过对正常人耳的动力响应分析,得到数值模型中计算出的鼓膜凸与镫骨底板振幅与试验数据吻合,验证本文模型的正确性。结论接在鼓膜凸的位置其动力响应最好,镫骨振幅高于其他连接方式。即人工听骨接在鼓膜凸的位置比较吻合人耳的生理功能,其重建听力效果更好。     

中耳结构动力响应对不同病理圆窗封闭的反馈

目的研究耳蜗圆窗病变对中耳结构力学行为的影响。方法依据临床健康志愿者右耳CT扫描结果,将CT扫描数据数值化导入PATRAN软件进行人耳三维有限元模型重建,并应用NASTRAN软件进行流固耦合频率响应分析,通过数值模拟方法探讨中耳结构动力响应对内耳耳蜗圆窗病变的反馈。结果硬化症导致的圆窗封闭比先天性圆窗封闭使镫骨振幅下降更多,最大达到30. 2 d B,且后者不会对镫骨振动速度产生明显影响。相位角方面,硬化症情况下镫骨和圆窗均最多产生90°变化,且两者保持180°差值;而先天性圆窗封闭情况下镫骨最大有270°变化,同时圆窗相位角变化消失。结论基于振幅、速度和相位角,镫骨动力行为会对先天性和硬化症导致的圆窗封闭形成不同的反馈表现,研究结果可为未来临床上诊断及修复圆窗病变提供理论支撑。     

细菌生物膜对置换钛质听骨赝复物听力恢复的影响

目的 探讨生物膜不同成长时期对部分钛质听骨赝复物结构动力行为的影响,为临床治疗分泌性中耳炎等疾病提供理论依据。方法 基于人体正常右耳的CT扫描图像,结合自编程序,重建人耳三维有限元模型,对其进行声音传导动力分析,并与实验数据对比。采用频率响应方法对耳结构模型进行计算,同时分析不同生长时期的细菌生物膜生长在人工钛质听骨上对声音传导的影响。结果 模拟得到鼓膜凸和镫骨底板振幅与实验数据吻合,验证了模型的正确性。生物膜的存在会使患者听力在低频段有0~1.6 dB的损伤;生物膜沿部分听骨赝复物径向生长会使患者听力在中高频阶段有0~12 dB的损伤,尤其是在8 kHz时,听力损伤高达11.2 dB。结论 细菌生物膜对患者听力有影响,在低频段会使患者听力损失,在高频段听力有增加。细菌生物膜在人工听骨上的径向生长会降低听力,影响人工假体对听力恢复正常的工效。     

细菌生物膜厚度和面积对人耳听力的影响

依据临床健康志愿者右耳的CT扫描结果,将CT扫描数据数值化导入PATRAN软件进行人耳三维有限元模型的重建,并用NASTRAN软件对该模型进行频率响应分析。通过对正常人耳结构进行频率响应分析得出数据与实验数据吻合,验证了模型的正确性。结合临床中耳炎病症实际情况,研究细菌生物膜的成长阶段对人耳听力的影响。结果表明：在不同声压相同的频率段,细菌生物膜的厚度变化对人耳听力的影响是相同的。在相同声压不同频率段,细菌生物膜的厚度增加会引起镫骨振幅和速度降低,在较低频率段镫骨振幅和速度下降幅度较大,下降的最大值为1.64 dB;在较高频率段镫骨振幅和速度下降幅度较小,下降的最大值为1.04 dB。在不同声压作用下,在相同的频率段细菌生物膜的面积增加会引起镫骨振幅和速度降低。在100～1 000 Hz频率段镫骨振幅和速度的下降幅度较小,下降的最大值为0.18 dB。在1000～10 000 Hz频率段镫骨振幅和速度的下降幅度较大,下降的最大值为2.26 dB。细菌生物膜厚度或面积增加都会使人耳听力下降,厚度增加在低频时比高频时下降更多,而面积增加则刚好相反。     

人耳鼓膜病变数值分析

目的研究鼓膜厚度和硬度对人耳传声的影响。方法利用CT获取志愿者耳部结构临床资料,使用Matlab软件提取相关结构的边界,将边界文件导入ANSYS建立人耳结构数值有限元模型。结果利用本文人耳数值模型,在外耳道口施加105dB声压,进行200～8000Hz频率范围的谐响应分析。以此研究在鼓膜病变情况下,鼓膜和镫骨底板位移幅值的变化规律。结论用数值方法解释了鼓膜病变对传声的影响,为鼓膜修补提供了力学参考。     

典型中耳病变对圆窗激振听力补偿性能影响的数值分析

目的研究典型中耳病变对圆窗激振听力补偿效果的影响,为圆窗激振式人工中耳的优化设计提供参考。方法利用CT扫描和逆向成型技术建立包括中耳和耳蜗的有限元模型,并验证模型的可靠性。再基于该模型,通过改变相应组织的材料属性,分别模拟镫骨环韧带硬化、镫骨不正常发育和锤骨前韧带硬化3种典型中耳病变。通过对比相应的基底膜响应,分析这3种病变对圆窗激振听力补偿效果的影响。结果镫骨不正常发育主要在高频处降低圆窗激振的效果,镫骨环韧带硬化和锤骨前韧带硬化主要恶化圆窗激振低频段的响应。3种病变中,镫骨环韧带硬化对圆窗激振听力补偿效果影响较大,等效声压的减小量可高达17 d B。结论中耳病变恶化圆窗激振的听力补偿效果,且恶化量较大,故在设计圆窗激振式人工中耳时需要针对性地提高其作动器的输出量。     

置换部分听骨赝复物后对人耳听力恢复的影响

目的探讨听骨部分置换术中不同的置换方式对患者术后听力的影响。方法根据人体正常右耳CT扫描结果,用自编程序将CT扫描数值化并导入PATRAN重建人耳三维有限元模型,对其进行声音传导动力分析,并与试验数据对比。结果通过正常人耳结构动力响应分析结果与实验数据吻合,验证了模型的正确性;在0.1～10 kHz频率下保留部分锤骨柄置换人工听骨比不保留锤骨柄术后听力恢复更好,听力恢复值在11.56～28.91 dB之间;保留部分锤骨柄时鼓膜处的最大应力值比不保留锤骨柄时更小;厚2.0 mm软骨片在0.1～0.6 kHz,2～10 kHz频率上听力恢复较好;厚0.1 mm软骨片在0.6～2 kHz频率上听力恢复较好。结论在听骨部分置换术中,保留部分锤骨柄比不保留锤骨柄听力恢复效果更好;鼓膜与人工听骨的接触面上垫置的软骨片厚度在0.1～2.0 mm之间对人耳听力恢复效果较好。     

高压下中耳结构动力损伤研究

目的研究高压对中耳结构造成的损伤。方法基于CT扫描建立中耳结构有限元数值模型,对模型施加随时间变化的压力,分析鼓膜以及镫骨足板的应力、应变和位移变化。结果获得的计算结果与相关文献中的试验数据吻合,验证了所建中耳模型的准确性。高压会对中耳造成损伤,随着压力的增加,损伤加重;快速加压使得中耳损伤严重,对内耳的影响较小;慢速加压也能导致中耳损伤,但在中耳损伤前,内耳会损伤。结论高压容易导致人耳出现损伤,为避免听力受到影响,在加压过程中要控制好加压速率。     

基于遗传算法反求耳结构弹性模量

本研究通过力学反问题原理,利用已知的位移求解耳结构弹性模量。随机产生遗传算法的初始种群,使用自编的Matlab算法程序,对初始种群进行遗传迭代计算,把已知的目标位移与种群位移的均方差作为目标函数,以目标函数值最小控制迭代进化的方向。通过耳结构的鼓膜凸和镫骨底板2个控制位移以及砧镫关节周围的8个控制位移这两个算例求解正常砧镫关节的弹性模量,并使用耳结构的鼓膜凸和镫骨底板2个控制位移求解病变砧镫关节的弹性模量。结果表明,使用基于遗传算法的反问题方法计算耳结构的弹性模量是可行的,并且具有稳定性和不受结构力学性能影响的特点,相对误差分别为0.05%和0.2%、0.03%,可为临床病变耳提供有效的力学参数。     

鼓膜穿孔对听力系统振动的影响

目的研究鼓膜穿孔尺寸及穿孔衍射对听力系统振动的影响。方法利用CT获取志愿者耳部结构临床资料,提取相关结构的边界,导入ANSYS并建立人耳结构数值有限元模型。结果穿孔面积分别为0.97、3.66和7.97mm2,随着穿孔尺寸增大,共振频率分别变为3.6、4.4和4.6kHz,镫骨底板位移振幅随之变小;镫骨底板位移振幅在衍射声波作用下明显变小;在1000Hz处,鼓膜位移云图位移最大值分别为0.32、0.20和0.19μm,在共振频率处,鼓膜位移云图位移最大值分别为0.20、0.14和0.09μm。结论鼓膜穿孔尺寸越大,镫骨底板位移振幅越小,尤其4kHz以下,共振频率升高。鼓膜云图位移振幅最大值随穿孔增大变小,有望对临床治疗提供参考。     

Three-Dimensional Finite Element Modeling of Human Ear for Sound Transmission

An accurate, comprehensive finite element model of the human ear can provide better understanding of sound transmission, and can be used for assessing the influence of diseases on hearing and the treatment of hearing loss. In this study, we proposed a three-dimensional finite element model of the human ear that included the external ear canal, tympanic membrane (eardrum), ossicular bones, middle ear suspensory ligaments/muscles, and middle ear cavity. This model was constructed based on a complete set of histological section images of a left ear temporal bone. The finite element (FE) model of the human ear was validated by comparing model-predicted ossicular movements at the stapes footplate and tympanic membrane with published experimental measurements on human temporal bones. The FE model was employed to predict the effects of eardrum thickness and stiffness, incudostapedial joint material, and cochlear load on acoustic-mechanical transmission through the human ossicular chain. The acoustic-structural coupled FE analysis between the ear canal air column and middle ear ossicles was also conducted and the results revealed that the peak responses of both tympanic membrane and stapes footplate occurred between 3000 and 4000 Hz.     

Modeling of Sound Transmission from Ear Canal to Cochlea

A 3-D finite element (FE) model of the human ear consisting of the external ear canal, middle ear, and cochlea is reported in this paper. The acoustic-structure-fluid coupled FE analysis was conducted on the model which included the air in the ear canal and middle ear cavity, the fluid in the cochlea, and the middle ear and cochlea structures (i.e., bones and soft tissues). The middle ear transfer function such as the movements of tympanic membrane, stapes footplate, and round window, the sound pressure gain across the middle ear, and the cochlear input impedance in response to sound stimulus applied in the ear canal were derived and compared with the published experimental measurements in human temporal bones. The frequency sensitivity of the basilar membrane motion and intracochlear pressure induced by sound pressure in the ear canal was predicted along the length of the basilar membrane from the basal turn to the apex. The satisfactory agreements between the model and experimental data in the literature indicate that the middle ear function was well simulated by the model and the simplified cochlea was able to correlate sound stimulus in the ear canal with vibration of the basilar membrane and pressure variation of the cochlear fluid. This study is the first step toward the development of a comprehensive FE model of the entire human ear for acoustic-mechanical analysis.     

Middle ear forward and reverse transmission in gerbil

The middle ear transmits environmental sound to the inner ear. It also transmits acoustic energy sourced within the inner ear out to the ear canal, where it can be detected with a sensitive microphone as an otoacoustic emission. Otoacoustic emissions are an important noninvasive measure of the condition of sensory hair cells and to use them most effectively one must know how they are shaped by the middle ear. In this contribution, forward and reverse transmissions through the middle ear were studied by simultaneously measuring intracochlear pressure in scala vestibuli near the stapes and ear canal pressure. Measurements were made in gerbil, in vivo, with acoustic two-tone stimuli. The forward transmission pressure gain was about 20-25 dB, with a phase-frequency relationship that could be fit by a straight line, and was thus characteristic of a delay, over a wide frequency range. The forward delay was about 32 micros. The reverse transmission pressure loss was on average about 35 dB, and the phase-frequency relationship was again delaylike with a delay of about 38 mus. Therefore to a first approximation the middle ear operates similarly in the forward and reverse directions. The observation that the amount of pressure reduction in reverse transmission was greater than the amount of pressure gain in forward transmission suggests that complex motions of the tympanic membrane and ossicles affect reverse more than forward transmission.     

正常人高分辨率CT中耳三维有限元建模方法

目的探索根据正常人颞骨高分辨率CT二维图像建立中耳三维有限元实体模型的方法。方法获得无中耳传音结构病变志愿者高分辨颞骨CT资料,使用Photoshop、Amira、HyperMesh及Abaqus软件根据二维CT图像建立中耳三维有限元实体模型。结果建立了包含鼓膜、听骨链的中耳三维有限元实体模型,模型几何尺寸在正常解剖数据范围内。结论探索出一种基于正常人颞骨高分辨率CT二维图像的中耳三维有限元实体建模方法,具有快捷、方便、廉价、无创性的优点,为进一步进行中耳声音传导机制有限元分析奠定了基础。