Dalbert Adrian, Sim Jae Hoon, Gerig Rahel, Pfiffner Flurin, Roosli Christof, Huber Alexander
Department of Otorhinolaryngology-Head and Neck Surgery, University Hospital Zurich, Switzerland.
Otol Neurotol. 2015 Aug;36(7):1172-80. doi: 10.1097/MAO.0000000000000768.
To monitor changes in cochlear function during cochlear implantation using electrocochleography (ECoG) and to correlate changes to postoperative hearing preservation.
ECoG responses to acoustic stimuli of 250, 500, and 1000 Hz were recorded during cochlear implantation. The recording electrode was placed on the promontory and stabilized to fix the position during cochlear implantation. Baseline recordings were obtained after completion of the posterior tympanotomy. Changes of the ongoing ECoG response at suprathreshold intensities were analyzed after full insertion of the cochlear implant electrode array. Audiometric tests were conducted before and 4 weeks after surgery and correlated with electrophysiological findings.
Ninety-five percent (18/19) of cochlear implant subjects had measurable ECoG responses. Under unchanged conditions, recordings showed a high repeatability without significant differences between 2 recordings (p ≤ 0.01). Ninety-four percent (17/18) of subjects showed no relevant changes in ECoG recordings after insertion of the cochlear implant electrode array. One subject showed decreases in responses at all frequencies indicative of cochlear trauma. This was associated with a complete hearing loss 4 weeks after surgery compared with mean presurgical low-frequency hearing of 78 dB HL.
Extracochlear ECoG is a reliable tool to assess cochlear function during cochlear implantation. Moderate threshold shifts could be caused by postoperative mechanisms or minor cochlear trauma. Detectable changes in extracochlear ECoG recordings, indicating gross cochlear trauma, are probably predictive of complete loss of residual acoustic hearing.
使用电耳蜗图（ECoG）监测人工耳蜗植入过程中耳蜗功能的变化，并将这些变化与术后听力保留情况相关联。
在人工耳蜗植入过程中记录对250、500和1000 Hz声音刺激的ECoG反应。记录电极置于岬部，并在人工耳蜗植入过程中固定以稳定位置。在完成后鼓室切开术后获取基线记录。在人工耳蜗电极阵列完全插入后，分析阈上强度下持续ECoG反应的变化。在手术前和术后4周进行听力测试，并与电生理结果相关联。
95%（18/19）的人工耳蜗植入受试者有可测量的ECoG反应。在条件不变的情况下，记录显示出高重复性，两次记录之间无显著差异（p≤0.01）。94%（17/18）的受试者在插入人工耳蜗电极阵列后ECoG记录无相关变化。一名受试者在所有频率下的反应均降低，提示耳蜗损伤。与术前平均低频听力78 dB HL相比，这与术后4周完全听力丧失有关。
耳蜗外ECoG是评估人工耳蜗植入过程中耳蜗功能的可靠工具。中度阈值变化可能由术后机制或轻微耳蜗损伤引起。耳蜗外ECoG记录中可检测到的变化，提示严重耳蜗损伤，可能预示残余听力完全丧失。
