Ohashi T, Kenmochi M, Kinoshita H, Ochi K, Yoshino K, Komatsuzaki A
Department of Otorhinolarnygology, St Marianna University School of Medicine, Kawasaki, Japan.
Acta Otolaryngol Suppl. 1996;522:17-21.
Pre-, per- and post-operative ECoG findings obtained from a 43-year-old woman with an acoustic neuroma were studied. Although CAP presented a normal waveform in response to click during the whole process of the operation, it was transformed into an abnormally broadened negative waveform in shape with a mild hearing exacerbation, and has remained unchanged up to the present. This broad response was considered to be a receptor potential, because it showed no adaptational amplitude reduction. Additionally, postoperative ECoG to tone burst stimuli demonstrated an increase in DC potential following the stimulus envelope. Consequently, the broad negative response to click was considered to be mainly composed of an enlarged negative SP. The generation mechanism underlying the phenomenon of an abnormally increased negative SP found after the excision of an acoustic neuroma is discussed, with reference to several items in the literature. Similar responses in the postoperative ECoG of patients with acoustic neuromas obtained by us in the past were given as additional examples. CAP as an indicator for intraoperative monitoring can hardly predict postoperative auditory function. It is to be hoped that a more reliable auditory monitoring method during the operation will be established.
对一名患有听神经瘤的43岁女性术前、术中及术后的皮层电图（ECoG）结果进行了研究。尽管在手术全过程中，短声诱发的复合动作电位（CAP）呈现正常波形，但在听力稍有加重时，它转变为形状异常变宽的负向波形，且至今仍未改变。这种宽大反应被认为是一种感受器电位，因为它没有出现适应性的幅度降低。此外，对短纯音刺激的术后ECoG显示，刺激包络后直流电位增加。因此，对短声的宽大负向反应被认为主要由增大的负向总和电位（SP）组成。参考文献中的几个要点，讨论了听神经瘤切除后出现负向SP异常增加现象的产生机制。我们还给出了过去所获得的听神经瘤患者术后ECoG的类似反应作为补充示例。CAP作为术中监测指标几乎无法预测术后听觉功能。希望能建立一种在手术期间更可靠的听觉监测方法。
