Calloway Nathan H, Fitzpatrick Douglas C, Campbell Adam P, Iseli Claire, Pulver Stephen, Buchman Craig A, Adunka Oliver F
Department of Otolaryngology, Head and Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, U.S.A.
Otol Neurotol. 2014 Sep;35(8):1451-7. doi: 10.1097/MAO.0000000000000451.
Electrophysiologic responses to acoustic stimuli are present in nearly all cochlear implant recipients when measured at the round window (RW). Intracochlear recording sites might provide an even larger signal and improve the sensitivity and the potential clinical utility of electrocochleography (ECoG). Thus, the goal of this study is to compare RW to intracochlear recording sites and to determine if such recordings can be used to monitor cochlear function during insertion of a cochlear implant.
Intraoperative ECoG recordings were obtained in subjects receiving a cochlear implant from the RW and from just inside scala tympani (n = 26). Stimuli were tones at high levels (80-100 dB HL). Further recordings were obtained during insertions of a temporary lateral cochlear wall electrode (n = 8). Response magnitudes were determined as the sum of the first and second harmonics amplitudes.
All subjects had measurable extracochlear responses at the RW. Twenty cases (78%) showed a larger intracochlear response, compared with three (11%) that had a smaller response and three that were unchanged. On average, signal amplitudes increased with increasing electrode insertion depths, with the largest increase between 15 and 20 mm from the RW.
ECoG to acoustic stimuli via an intracochlear electrode is feasible in standard cochlear implant recipients. The increased signal can improve the speed and efficiency of data collection. The growth of response magnitudes with deeper intrascalar electrode positions could be explained by closer proximity or favorable geometry with respect to residual apical signal generators. Reductions in magnitude may represent unfavorable geometry or cochlear trauma.
当在圆窗（RW）处进行测量时，几乎所有人工耳蜗植入受者对声刺激都有电生理反应。耳蜗内记录部位可能会提供更大的信号，并提高电耳蜗图（ECoG）的灵敏度和潜在临床应用价值。因此，本研究的目的是比较圆窗与耳蜗内记录部位，并确定这种记录是否可用于在人工耳蜗植入过程中监测耳蜗功能。
在接受人工耳蜗植入的受试者中，从圆窗和鼓阶内刚进入处获取术中ECoG记录（n = 26）。刺激为高强度纯音（80 - 100 dB HL）。在插入临时外侧耳蜗壁电极期间进一步进行记录（n = 8）。将反应幅度确定为基波和二次谐波幅度之和。
所有受试者在圆窗处均有可测量的耳蜗外反应。20例（78%）显示耳蜗内反应更大，相比之下，3例（11%）反应较小，3例无变化。平均而言，信号幅度随电极插入深度增加而增大，在距圆窗15至20 mm之间增加最大。
对于标准人工耳蜗植入受者，通过耳蜗内电极进行声刺激的ECoG是可行的。增加的信号可提高数据采集的速度和效率。随着鼓阶内电极位置加深反应幅度增大，这可能是由于与残留的顶端信号发生器距离更近或几何关系有利。幅度降低可能表示几何关系不利或耳蜗损伤。
