Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
Otol Neurotol. 2022 Feb 1;43(2):e181-e190. doi: 10.1097/MAO.0000000000003414.
To assess the prevalence and implications of phase changes in extracochlear electrocochleography (ECochG) recordings during cochlear implantation.
Extracochlear ECochG recordings were performed before and after insertion of the cochlear implant (CI) electrode by a recording electrode placed on the promontory. Acoustic stimuli were tone bursts at 250, 500, 750, and 1,000 Hz. The pure tone average (PTA) was determined before and approximately 4 weeks after surgery.
Extracochlear ECochG recordings in 69 ears of 68 subjects were included. At 250 Hz, the mean phase change was 43° (n = 50, standard deviation (SD) 44°), at 500 Hz 36° (n = 64, SD 36°), at 750 Hz 33° (n = 42, SD 39°), and at 1,000 Hz 22° (n = 54, SD 27°). Overall, in 48 out of 210 ECochG recordings a phase change of ≥45° (23%) was detectable. Ears with an amplitude drop >3 dB and a phase change ≥45° (n = 3) had a complete or near complete loss of residual cochlear function in all cases. A phase change of ≥90° in one recording was not associated with a larger amplitude change of the ECochG signal (1.9 dB vs. -0.9 dB, p = 0.1052, n = 69), but with a significantly larger postoperative hearing loss (17 dB vs. 26 dB, p = 0.0156, n = 69).
Phase changes occur regularly in extracochlear ECochG recordings during cochlear implantation. Phase changes of ≥90° with or without amplitude changes in the ECochG signal are associated with a larger postoperative hearing loss and could therefore represent an independent marker for cochlear trauma or changes of inner ear mechanics relevant for the postoperative hearing outcome.
评估人工耳蜗植入过程中外耳道电描记术中相位变化的发生率及其影响。
通过置于鼓岬的记录电极，在植入人工耳蜗（CI）电极之前和之后进行外耳 ECochG 记录。声刺激为 250、500、750 和 1000Hz 的短音。术前和术后约 4 周时确定纯音平均听阈（PTA）。
纳入 68 例 69 耳的外耳 ECochG 记录。250Hz 时，平均相位变化为 43°（n=50，标准差 44°），500Hz 时为 36°（n=64，标准差 36°），750Hz 时为 33°（n=42，标准差 39°），1000Hz 时为 22°（n=54，标准差 27°）。总体而言，在 210 次 ECochG 记录中，有 48 次（23%）可检测到≥45°的相位变化。振幅下降>3dB 且相位变化≥45°（n=3）的耳朵在所有情况下均存在残余耳蜗功能完全或近乎完全丧失。1 次记录中的相位变化≥90°与 ECochG 信号的振幅变化较大无关（1.9dB 与-0.9dB，p=0.1052，n=69），但与术后听力损失明显增大相关（17dB 与 26dB，p=0.0156，n=69）。
在外耳道电描记术中，人工耳蜗植入过程中会出现相位变化。ECochG 信号中存在≥90°的相位变化和/或振幅变化与术后听力损失较大有关，因此可能是耳蜗创伤或内耳力学变化的独立标志物，这些变化与术后听力结果相关。
