振子及其耦合条件对圆窗激励式人工中耳性能影响的数值研究

The effect of an actuator and its coupling conditions on round window-stimulated middle ear implants:a numerical analysis

为研究振子及其耦合条件对圆窗激励式人工中耳植入性能的影响,建立了包括振子和隔膜在内的人耳有限元模型。该模型基于一无任何听力损伤病史的成年志愿者右耳,采用CT扫描和逆向成型技术建立而成,通过与相关文献的实验数据比对验证了模型的可靠性。基于该模型,分析了圆窗上的初始预压力、振子和隔膜的设计参数变化对振子听力性能的影响。结果表明:振子横截面积越大,其对耳蜗的激励效果越差;隔膜的引入有利于提高振子的激振性能,在该研究范围内,较小的隔膜杨氏模量和厚度有利于提升振子的激振性能;振子质量的增加会恶化振子在高频段的植入性能;在圆窗上施加的初始预压力能够提高中高频段上对耳蜗的激振效果。

Consisting of the actuator and a coupling layer, a finite element （FE） model of the human ear was used to analyze the effect of the actuator and its coupling conditions on the performance of round window-stimulated （ RW- S） middle ear implants （ MEIs） . The model,based on the right ear of a healthy adult, was built via micro-computer tomography imaging and the technique of reverse engineering. The validity of the model was verified by comparing the model simulated results with experimental data. The influence of the constant pretension of the round window, two main design parameters of the actuator and two aspects of the coupling layer were investigated by the FE model. The results show that： the larger cross-section of the actuator, the worse effect on the implant performance of the RW-S MEI; the introduction of coupling layer between the actuator and RW could effectively improve the implant performance of RW stimulation; however, the degree of this improvement would be reduced with the increase of the thickness and the Young^ modulus of the coupling layer in the research scope; the actuator’s stimulated performance at high frequencies will be deteriorated with the increase of the actuators mass; the constant pretension applied to the round window is beneficial for sound transmission to the cochlear at middle-high frequency range.