University of Zurich, Zurich, Switzerland.
Department of Otorhinolaryngology-Head and Neck Surgery, University Hospital of Zurich, Zurich, Switzerland.
Trends Hear. 2021 Jan-Dec;25:2331216521990594. doi: 10.1177/2331216521990594.
The use of electrocochleography (ECochG) for providing real-time feedback of cochlear function during cochlear implantation is receiving increased attention for preventing cochlear trauma and preserving residual hearing. Although various studies investigated the relationship between intra-operative ECochG measurements and surgical outcomes in recent years, the limited interpretability of ECochG response changes leads to conflicting study results and prevents the adoption of this method for clinical use. Specifically, the movement of the recording electrode with respect to the different signal generators in intracochlear recordings makes the interpretation of signal changes with respect to cochlear trauma difficult. Here, we demonstrate that comparison of ECochG signals recorded simultaneously from intracochlear locations and from a fixed extracochlear location can potentially allow a differentiation between traumatic and atraumatic signal changes in intracochlear recordings. We measured ECochG responses to 500 Hz tone bursts with alternating starting phases during cochlear implant insertions in six human cochlear implant recipients. Our results show that an amplitude decrease with associated near 180° phase shift and harmonic distortions in the intracochlear difference curve during the first half of insertion was not accompanied by a decrease in the extracochlear difference curve's amplitude (= 1), while late amplitude decreases in intracochlear difference curves (near full insertion, = 2) did correspond to extracochlear amplitude decreases. These findings suggest a role for phase shifts, harmonic distortions, and recording location in interpreting intracochlear ECochG responses.
在进行人工耳蜗植入术时，电 Cochleography（ECochG）可实时反馈耳蜗功能，有助于预防耳蜗创伤和保护残余听力，目前正受到越来越多的关注。近年来，虽然有多项研究调查了术中 ECochG 测量值与手术结果之间的关系，但由于 ECochG 响应变化的可解释性有限，导致研究结果相互矛盾，无法将该方法应用于临床。具体而言，由于在耳蜗内记录中，记录电极相对于不同信号发生器的运动使得很难根据耳蜗创伤来解释信号变化。在这里，我们证明了同时从耳蜗内和固定的耳蜗外位置记录的 ECochG 信号的比较，可能有助于区分耳蜗内记录中的创伤性和非创伤性信号变化。我们在六位人工耳蜗植入受者进行人工耳蜗植入时，测量了 500 Hz 音爆的 ECochG 反应，这些音爆的起始相位交替。我们的结果表明，在插入的前半部分，与近 180°相位偏移和耳蜗内差曲线中的谐波失真相关的幅度降低，但耳蜗外差曲线的幅度（= 1）并没有降低；而耳蜗内差曲线的晚期幅度降低（接近完全插入，= 2）与耳蜗外幅度降低相对应。这些发现提示相位偏移、谐波失真和记录位置在解释耳蜗内 ECochG 反应中起作用。
