耳蝸電圖檢查的臨床應用

Clinical Application of Electrocochleography

王興萬(Hsing-Won Wang) ； 葉文英(Wun-Ying Yeh) ； 康柏皇(Bor-Hwang Kang)

《The Changhua Journal of Medicine》 9卷s期 (2004/12) Pp. 243-248

摘要

多年來，有關耳蝸電圖中summating potential (SP)/ action potential (AP)的比值，早已廣泛的用於梅尼爾氏症的診斷。一般而言，對典型的梅尼爾氏症之診斷，比較不會有任何爭議；但若非典型的梅尼爾氏症出現時，如只有出現部份症狀，在未有耳蝸電圖時，則缺乏一客觀的檢查，以確定病人是否有內淋巴水腫。耳蝸電圖的出現，建立了診斷梅尼爾氏症的另一個里程碑，它讓我們更深入了解內耳的電生理功能。內淋巴水腫呈現特殊的耳蝸電圖變化，有典型的SP擴大或SP/AP比值增加，產生的機轉源於基底膜的機械性變化或擠壓。
梅尼爾氏症為一漸進式及浮動性疾病。因此，不同時期的梅尼爾氏症，耳蝸電圖的表現並不相同。一般認為早期的梅尼爾氏症，其耳蝸電圖的測試最靈敏。
本文獻回顧旨在討論如何得到耳蝸電圖，並探討其涵義與臨床上的應用，尤其是在梅尼爾氏症的變化。本院目前採用耳膜電極所求得的耳蝸電圖，乃一將主電極放置耳膜上的非侵入性檢查，容易操作且對梅尼爾氏症的診斷，助益頗大，值得推廣。

關鍵字

耳蝸電圖檢查 ； 梅尼爾氏症 ； 內淋巴水腫 ； 耳膜電極

並列摘要

For more than two decades, researchers have reported the ratio of the summation potential (SP) amplitude relative to the action potential (AP) amplitude, commonly referred to as the SP/AP amplitude ratio, to be useful in the diagnosis of Meniere's disease. Researchers have questioned the existence of cochlear Meniere's disease-once considered a variant of classic Meniere's disease unassociated with vertigo-because they lacked the objective evidence necessary to prove that endolymphatic hydrops is involved with the disease process. Electrocochleography (ECoG) may provide another avenue towards the understanding of Meniere's disease, as it offers unique insights into the electrical functioning of the inner ear. Distinctive electrocochleographic changes characterize cochlear conditions associated with endolymphatic hydrops. Researches assume that the generation of SP dominance or the increased SP/AP ratio in Meniere's disease or endolymphatic hydrops is due to mechanical asymmetry of the basilar membrane.
The classical view of Meniere's disease is that of a progressive, fluctuating disease in which ECoG characteristics vary with disease state. Human and animal studies suggest that ECoG is most sensitive in early stages of the disease before permanent damage to cochlear structures has occurred.
The goals of this review are to present methods for obtaining electrocochleographic recordings while focusing on essential methodological factors, and to discuss the clinical applications of ECoG, specifically to patients with Meniere's disease. Tympanic ECoG is a noninvasive technique for recording cochlear potentials with an electrode placed on the tympanic membrane. Tympanic ECoG is uncomplicated and practical for the diagnosis of Meniere's disease.

並列關鍵字

electrocochleograph ； Meniere's disease ； endolymphatic hydrop ； tympanic electrode