新型可植入式压电传感器提取听骨链声信号与处理策略的基础研究

Cochlear implant is the one way to help profound deaf patients regain their sound perception. Cochlear implants have many exterior components, which lead some inconvenience. To eliminate the disadvantages, it is essential to study the totally implantable cochlear implants, with one challenge of the implantable microphone. The previous studies proved the possibility of picking up the acoustic from the ossicular chain in human by floating piezoelectric microphone, and we have manufactured the new floating piezoelectric microphone (NFPM) with good capsulation and biocompatibility. While, long-term research in clinic should be studied. The study will study the best way of NFPM coupled with ossicular chain. Laser doppler vibrometry (LDV) was used to measure the vibration of tympanic membrane, ossicular chain, round window and NFPM when NFPM coupled with ossicular chain in animals/ fresh cadaveric heads. And the frequency response and biocompatibility of NFPM coupled with ossicular chain in animals/ fresh cadaveric heads in long-term will be studied. Then the measurement and signal processing of the acoustic pickup were performed. Optimize the signals picked up from the NFPM, recover the primary character of the full-band acoustic signals. All the studies will discuss the best way of NFPM coupled with ossicular chain, biocompatibility and acoustic signals processing in the process of picking up acoustic signals from ossicular chain which will provide the references for the totally implantable cochlear implants’ clinical application.

人工耳蜗是重度感音性聋患者重获听觉的唯一手段，为部分植入式，存在诸多不便，全植入人工耳蜗作为下一代耳蜗的研究方向，需要解决可植入式传感器难题。我们前期工作研制出新型中耳植入式压电传感器可提取听骨链振动声学信号，但其临床植入的可行性有待研究。本项目首先通过对人新鲜颞骨标本及猫听骨链不同位置植入新型传感器前后鼓膜、听骨链、圆窗膜和传感器振动数据的测量，研究植入传感器对中耳传音过程的影响，选取最佳植入位置；然后通过对新型传感器在人颞骨标本及猫听骨链不同植入位置提取信号进行测试分析，研究其实时以及长期提取听骨链声信号的频响性能以及长期植入生物相容性，选取提取最佳信号的植入位置；最后对其提取的听骨链声信号进行优化补偿处理，复原全频段声音信号的原始特征。本研究将建立新型传感器提取听骨链声信号的最佳植入方案，阐明长期植入的生物相容性并对提取信号进行优化处理，为全植入人工耳蜗的临床植入及应用提供理论依据。

背景：人工耳蜗是重度感音性聋患者重获听觉的唯一手段，目前临床应用的人工耳蜗均为部分植入式，体外部分给使用者带来许多不便，全植入式人工耳蜗是未来的研究方向，其中可植入式传感器是最大挑战。主要研究内容和重要结果：本项目在前期研制的新型中耳植入式压电传感器基础上，通过新型压电传感器植入人体新鲜颞骨标本和实验动物听骨的实验，测振发现新型压电传感器植入前后对听骨链振动特性的改变不大，不影响中耳传音过程，耦合于听骨的传感器能够产生相应的频响位移，对其提取信号分析发现传感器耦合于听骨能有效提取听骨链振动声学信号并且具有良好的频响性能，砧骨长突是传感器最佳植入位置。其次，通过新型可植入式压电传感器在实验动物听骨长期植入实验，发现传感器植入六个月后，实验动物生命体征良好，仅在传感器周围有少许的肉芽组织增生，钛夹与听骨耦合良好、无松动，听骨活动良好，无缺血坏死及固定表现，说明传感器具有良好的生物相容性，对其提取信号分析发现长期植入后传感器仍有较好的提取声信号稳定性及频响性能。同时，通过对新型传感器提取信号优化处理，发现处理后信号的信噪比明显增加，总体谐波失真明显减小，信号质量明显提高，传感器提取信号与现有的人工耳蜗系统相结合，信号可以分配在正确的电极位点上。科学意义：本研究项目结果表明新型压电传感器耦合于砧骨长突能有效提取听骨链振动声学信号，长期植入具有良好的稳定性和生物相容性，优化处理后的信号能正确分配到电极位点，为以其为基础设计全植入人工耳蜗的临床植入及应用提供了可行性及理论依据。