圆窗激振式人工中耳振子结构优化设计及频响补偿增益研究

Round-window stimulation is a new direction for the development of middle ear implant, which avoids the ossicular chain and compensates the hearing loss directly. It is one of the most promising techniques for treating mixed hearing loss. But its clinical utilization turns out some shortcomings, i.e., performance evaluation index for it is not accurate, higher clinical individual variability, lower output gain at high and low frequencies, and no dedicated frequency-response compensation fitting algorithm. Based on our previous human ear mechanics study, this project will investigate the movements of the stapes and the inner hair cell stereocillia under normal sound transmission and round-window stimulation, and modify the existing hearing compensation performance evaluation index. Besides, to ascertain the gain of the actuator for overcoming the typical conductive hearing loss, the influence of the external ear and middle ear deformity, otosclerosis and Otitis media on the round-window stimulation will be studied. Moreover, we will introduce the piezoelectric stack with good performance at higher frequencies to the design of the actuator, and incorporate a flextensional amplifier for it to reduce its energy consumption and improve its low-frequency response. After that, a support for the actuator will be designed based on the anatomical study of the human ear. Furthermore, an actuator- round window coupling mechanical model will be established. And by analyzing the influence of piezoelectric stack's layer number, piezoelectric strain coefficient, flextensional amplifier structural dimensions and other key design parameters on the actuator’s performance, and taking the minimum energy consumption as the objective function, the structure of the actuator will be optimized. Finally, the mapping relationship between the actuator driving voltage and the human perceived loudness will be established, and a fitting algorithm for the frequency-response compensation of the round-window stimulation will be developed. The research results lay a theoretical foundation for the improvement and development of middle ear implant, and provide a reliable solution for mixed hearing loss.

圆窗激振是人工中耳发展的一个新方向，它避开听骨链直接补偿听力损伤，是治疗混合性聋最有潜力的技术之一。但其性能评价指标不准确，临床个体差异大，高低频增益差，无频响补偿增益适配算法。本项目在现有耳力学研究基础上，对比研究正常感声及圆窗激振下镫骨、内毛细胞纤毛运动，修正现有听力补偿性能评价指标；研究外中耳畸形、耳硬化、中耳炎等对圆窗激振影响，确定振子克服典型传导性病变所需增益；将高频增益优越的压电叠堆用于振子驱动，并引入弯张放大结构降低能耗、提升低频响应；结合耳解剖学研究，设计支撑装置，建立振子—圆窗耦合力学模型，分析叠堆层数、压电应变系数、弯张放大器结构尺寸等关键设计参数对振子性能影响，以能耗最小为目标函数优化振子结构；建立圆窗激振人耳感声响度模型，构建振子驱动电压至响度间映射关系，开发圆窗激振频响补偿增益适配算法。研究成果为人工中耳综合性能提升、开发奠定理论基础，为混合性耳聋提供可靠解决方案

圆窗激振是人工中耳发展的一个新方向，它避开听骨链，直接激振耳蜗圆窗膜来补偿听力损伤，是治疗混合性聋最有潜力的技术之一。但其性能评价指标不准确，临床个体差异大，高低频增益差。本项目针对上述问题，基于耳蜗解剖结构，建立了耳蜗基部、中部及顶部微观力学模型，对比分析了正向激振、圆窗激振下的基底膜位移与内听毛细胞静纤毛剪切位移，修正了现有基于镫骨运动的圆窗激振式人工中耳性能评价指标。构建了考虑耳蜗前庭阶与鼓阶不对称结构、耳蜗螺旋结构、及耳蜗第三窗的整耳传声力学模型，系统研究了中耳炎、耳硬化、中耳畸形典型传导性病变对圆窗激振听力补偿性能的影响，确定了人工中耳作动器克服这些传导性听损病变所需的输出增益特性。结合圆窗龛及中耳腔解剖结构，优化设计了一款基于压电叠堆，且配有弯张放大器、载荷指示器的圆窗激振式人工中耳作动器，实验测试显示所设计的作动器相对与现有人工中耳，作动端与圆窗膜横截面积匹配，手术植入过程中初始压力可监控，且具有优异的低频、高频特性、总谐波失真低。在该作动器基础上，引入了变刚度支撑弹簧、位置微调机构，进一步提升了作动器高频性能，降低了该作动器手术植入中的调整难度。研究了一套基于非负矩阵分解与深度神经网络相结合的目标融合语音增强方法，降低带噪语音中的噪声信号，提高了人工中耳复杂噪声环境下的语音质量与可懂度。研究了基于快速区域卷积神经网络的中耳炎影像计算机辅助诊断方法，及中耳畸形对宽频声导抗诊断时能量吸收率的影响，探索了混合性听力损伤中传导性病变的临床精准检测技术。