Leibniz University Hannover, Institute of Electrical Engineering and Measurement Technology, Department of Sensors and Measurement Technology, Appelstr. 9A, Hannover 30167, Germany.
Hannover Medical School, Department of Otolaryngology/NIFE and Cluster of Excellence "Hearing4all", Stadtfelddamm 34, Hannover 30625, Germany.
Hear Res. 2024 Nov;453:109125. doi: 10.1016/j.heares.2024.109125. Epub 2024 Oct 4.
Although cochlear implants are an established method of restoring hearing, they can have limitations such as increasing current spread and decreasing frequency resolution due to tissue growth around the electrode array. Impedance measurements in cochlear implants have become a versatile tool for intra- and post-operative diagnosis of cochlear implant state. However, most clinical devices use current pulse stimulation already available in the implants and analyze the voltage response in the time-domain and spread along the cochlea. To use the full potential of impedance spectroscopy in differentiating cell types, measurement over an extended frequency range is required. This study presents a simple electrical equivalent circuit for impedance spectroscopy with cochlear implants in a 2-pole configuration. The electrical equivalent circuit describes the electrical properties of the cochlear implant electrode and its electrochemical behavior at the electrode-electrolyte interface by comparing two non-linear bilayer models, Cole-Cole and Schwan-Faraday. The model is validated for four cochlear implant electrodes from four different manufacturers (MED-EL FlexSoft, AB HiFocus SlimJ, Oticon EVO, Cochlear Nucleus CI622) characterized by impedance spectroscopy between 5 Hz and 13 MHz. In the future, this electrical equivalent circuit may help to extract parameters for differentiating cell types around the cochlear implant electrode from an impedance spectroscopic measurement.
虽然人工耳蜗植入物是一种已确立的恢复听力的方法，但由于电极阵列周围的组织生长，它们可能会有限制，例如增加电流扩散和降低频率分辨率。人工耳蜗植入物中的阻抗测量已成为一种用于植入物内和术后诊断的多功能工具。然而，大多数临床设备使用已经在植入物中可用的电流脉冲刺激，并在时域和沿着耳蜗传播的方向分析电压响应。为了充分利用阻抗谱在区分细胞类型方面的潜力，需要在扩展的频率范围内进行测量。本研究提出了一种用于 2 极配置的人工耳蜗植入物的阻抗谱的简单等效电路。该等效电路通过比较两个非线性双层模型——Cole-Cole 和 Schwan-Faraday，描述了人工耳蜗植入电极的电学特性及其在电极-电解质界面的电化学行为。该模型通过阻抗谱在 5 Hz 和 13 MHz 之间对来自四个不同制造商（MED-EL FlexSoft、AB HiFocus SlimJ、Oticon EVO 和 Cochlear Nucleus CI622）的四个人工耳蜗植入电极进行了验证。未来，这种等效电路可能有助于从阻抗谱测量中提取用于区分人工耳蜗植入电极周围细胞类型的参数。
