Haumann Sabine, Timm Max E, Büchner Andreas, Lenarz Thomas, Salcher Rolf B
Department of Otorhinolaryngology, Hannover Medical School, Hanover, Germany.
Cluster of Excellence "Hearing4all", Hanover, Germany.
Front Neurosci. 2025 Jan 16;18:1530216. doi: 10.3389/fnins.2024.1530216. eCollection 2024.
During cochlear implant (CI) surgery, it is desirable to perform intraoperative measurements such as Electrocochleography (ECochG) to monitor the inner ear function and thereby to support the preservation of residual hearing. However, a significant challenge arises as the recording location of intracochlear ECochG via the CI electrode changes during electrode insertion. This study aimed to investigate the relationships between intracochlear ECochG recordings, the position of the recording contact within the cochlea relative to its anatomy, and the implications for frequency and residual hearing preservation. Intraoperative ECochG recordings were conducted using the CI electrode (MED-EL) during the insertion of hearing preservation electrodes and after the insertion process. Recordings were continuously conducted using the most apical electrode (contact 1) during insertion. After insertion, the recordings were performed on all different electrode contacts. The electrode location in the cochlea during insertion was estimated using mathematical models and preoperative clinical imaging, while the postoperative electrode position was determined using postoperative clinical imaging. The study involved 10 adult CI recipients. In those with good low-frequency hearing, an increase in signal amplitude was observed, with the highest amplitudes closest to the stimulation frequency generators, and no phase change was observed. Conversely, patients with flat hearing loss exhibited a second peak with an opposite phase in the medial area of the cochlea. This study is the first to suggest that the pattern of the preoperative audiogram may influence the ECochG outcomes measured intraoperatively. Specifically, the ECochG responses during insertion appeared to behave as expected with good low-frequency hearing, while with flat hearing loss there appear to be further effects. These findings indicate that this approach can provide valuable information for the interpretation of intracochlearly recorded ECochG signals.
在人工耳蜗（CI）植入手术中，进行诸如电耳蜗图（ECochG）等术中测量以监测内耳功能，从而支持残余听力的保留是很有必要的。然而，随着通过CI电极进行的耳蜗内ECochG记录位置在电极插入过程中发生变化，出现了一个重大挑战。本研究旨在探讨耳蜗内ECochG记录、记录触点在耳蜗内相对于其解剖结构的位置之间的关系，以及对频率和残余听力保留的影响。在插入听力保留电极期间及插入过程后，使用CI电极（MED-EL）进行术中ECochG记录。在插入过程中，使用最顶端的电极（触点1）持续进行记录。插入后，在所有不同的电极触点上进行记录。使用数学模型和术前临床成像估计插入过程中电极在耳蜗内的位置，而术后电极位置则通过术后临床成像确定。该研究涉及10名成年CI接受者。在低频听力良好的患者中，观察到信号幅度增加，最高幅度最接近刺激频率发生器，且未观察到相位变化。相反，听力损失平坦的患者在耳蜗内侧区域出现了一个相位相反的第二个峰值。本研究首次表明，术前听力图的模式可能会影响术中测量的ECochG结果。具体而言，在插入过程中，ECochG反应在低频听力良好时似乎表现如预期，而在听力损失平坦时似乎有进一步的影响。这些发现表明，这种方法可以为解释耳蜗内记录的ECochG信号提供有价值的信息。
