新型压电传感器提取听骨链声信号及后期处理

发布时间：2019-05-17 03:04

【摘要】：目的：采用真空封装,增加钛夹等方法,研制新型压电传感器,通过新型压电传感器与新鲜颞骨标本和活体猫耳内的听骨链耦合,拾取体外声信号,并对声信号进行后期处理的实验研究,系统验证听骨链振动拾音策略的可行性,为全植入人工耳蜗体内拾音提供解决方案。方法：(1)通过增加钛夹、引线管绝缘子及激光封装,制作出新型压电传感器,并将其固定于扬声器防风罩上进行体外模拟实验。(2)建立新型压电传感器耦合于人耳听骨链时的三维重建模型,利用有限元分析模拟听骨链在耦合新型压电传感器前后频响位移变化以及新型压电传感器在人听骨链上的频响位移情况。(3)将新型压电传感器植入新鲜颞骨标本的听骨链砧骨长突和鼓室腔,共实验7耳(6副尸头),分别记录不同频率下的频响反应。(4)新型压电传感器植入新鲜颞骨,测试系统给与Burst信号,NI仪器同步记录新型压电传感器的输入信号及输出信号,从而分析传感器系统的相对延迟时间。(5)将新型压电传感器植入活体猫耳听骨链的锤骨颈和听泡内,共实验5耳(4只猫),分别记录不同频率下的频响反应。(6)对新型压电传感器拾取信号的畸变和失真进行处理,通过计算信号的总谐波失真和信噪比,比较处理前后信号的质量。结果：(1)体外模拟实验发现质量为67 mg的新型压电传感器能灵敏地拾取全频段可听见声声学信号,具有较平坦的频响曲线,可用于体内植入实验。(2)有限元分析发现将新型压电传感器耦合于砧骨长突,对镫骨底板的频响位移影响不大,1000Hz以下略有增大,1000Hz以上略有减小。固定于砧骨长突的新型压电传感器能够产生相应的位移反应但是略低于镫骨底板的运动。(3)新鲜颞骨标本植入实验发现,新型压电传感器耦合于砧骨长突后能拾取体外声学信号,且低频干扰小,共振现象弱,与悬空于鼓室腔对照(-92.94 dB rms ref 1V at 1000Hz),其与听骨砧骨长突耦合后有较好的频谱响应(-56.58 dB rms ref 1V at 1000Hz), 100Hz-10000Hz频响曲线较平坦。(4)比较输入与输出信号通道的相位差,发现新型压电传感器的相对延迟时间为14.75 ms。(5)活体猫耳植入实验发现,新型压电传感器耦合于锤骨颈后能拾取体外声学信号,与放置于听泡内对照(-87.43 dB rms ref 1V at 1000Hz),其与锤骨颈耦合后有较好的频谱响应(-46.92 dB rms ref 1V at 1000Hz), 100Hz-10000Hz频响曲线较平坦。(6)处理后信号与原始信号相比信噪比明显升高,总体谐波失真明显减小。结论：(1)研制出应用钛夹的固定方式,具有较好的密封性和生物相容性的新型压电传感器。(2)通过系统实验初步论证了新型压电传感器拾取听骨链振动声学信号的可行性。(3)新型压电传感器拾取的信号经过处理后能够进一步提高信号质量。(4)新型压电传感器与耳蜗内电极结合,以及其长期植入效果和并发症等仍需进一步深入研究。
[Abstract]:Objective: to develop a new piezoelectric sensor by vacuum encapsulation and titanium clip, and to pick up the acoustic signal in vitro by coupling the new piezoelectric sensor with the ossicular chain in the ears of fresh temporal bone specimens and living cats. The experimental study on the post-processing of acoustic signals systematically verified the feasibility of the sound picking strategy of ossicular chain vibration, and provided a solution for the whole cochlear implantation. Methods: (1) A new piezoelectric sensor was fabricated by adding titanium clip, lead tube insulator and laser package. The simulation experiment in vitro was carried out by fixing it on the loudspeaker windshield. (2) A three-dimensional reconstruction model of a new piezoelectric sensor coupled to the human auditory ossicular chain was established. Finite element analysis is used to simulate the frequency response displacement of ossicular chain before and after coupling the new piezoelectric sensor and the frequency response displacement of the new piezoelectric sensor on the human ossicular chain. (3) the new piezoelectric sensor is implanted into the fresh temporal bone. The ossicular chain incus long process and tympanic cavity of the specimen, A total of 7 ears (6 cadaveric heads) were tested to record the frequency response at different frequencies. (4) the new piezoelectric sensor was implanted into fresh temporal bone, and the Burst signal was given by the test system. The input signal and output signal of the new piezoelectric sensor are recorded synchronously by NI instrument, thus the relative delay time of the sensor system is analyzed. (5) the new piezoelectric sensor is implanted into the hammer neck and auditory vesicle of the auditory ossicular chain of the cat in vivo. A total of 5 ears (4 cats) were tested to record the frequency response at different frequencies. (6) the distortion and distortion of the pick-up signal of the new piezoelectric sensor were processed, and the total harmonic distortion and signal-to-noise ratio of the signal were calculated. The quality of the signal before and after processing is compared. Results: (1) it was found that the new piezoelectric sensor with a mass of 67 mg could sensitively pick up audible acoustic signals in the whole frequency band and had a flat frequency response curve. It can be used in vivo implantation experiment. (2) finite element analysis shows that the coupling of the new piezoelectric sensor to the long process of incus has little effect on the frequency response displacement of stapes floor, but increases slightly below 1000Hz and decreases slightly above 1000Hz. The new piezoelectric sensor fixed to the long process of incus can produce the corresponding displacement response, but slightly lower than the movement of stapes floor. (3) fresh temporal bone implantation experiment found, After coupling to the long process of incus, the new piezoelectric sensor can pick up the acoustic signal in vitro, and the low frequency interference is small and the resonance phenomenon is weak, which is compared with that suspended in tympanic cavity (- 92.94 dB rms ref 1V at 1000Hz). After coupling with the long process of ossicular anvil, it has a better spectral response (- 56.58 dB rms ref 1V at 1000Hz), and the 100Hz-10000Hz frequency response curve is flat. (4) the phase difference between input and output signal channels is compared. It is found that the relative delay time of the new piezoelectric sensor is 14.75 ms. (5). It is found that the new piezoelectric sensor can pick up the acoustic signal in vitro after coupling to the hammer neck. Compared with that placed in auditory vesicle (- 87.43 dB rms ref 1V at 1000Hz), it had a better spectral response (- 46.92 dB rms ref 1V at 1000Hz) after coupling with hammer neck. The 100Hz-10000Hz frequency response curve is flat. (6) compared with the original signal, the signal-to-noise ratio (SNR) of the processed signal is obviously increased, and the overall harmonic distortion is obviously reduced. Conclusion: (1) the fixation method with titanium clip has been developed. A new type of piezoelectric sensor with good sealing and biocompatibility is proposed. (2) the feasibility of picking up the acoustic signal of ossicular chain vibration by a new piezoelectric sensor is preliminarily demonstrated by systematic experiments. (3) A new piezoelectric sensor After processing, the picked signal can further improve the signal quality. (4) the new piezoelectric sensor is combined with the inner electrode of the cochlea. The long-term implantation effect and complications still need to be further studied.
【学位授予单位】：复旦大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：R764

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