Chihara Yasuhiro, Iwasaki Shinichi, Ushio Munetaka, Fujimoto Chisato, Kashio Akinori, Kondo Kenji, Ito Ken, Asakage Takahiro, Yamasoba Tatsuya, Kaga Kimitaka, Murofushi Toshihisa
Department of Otolaryngology-Head and Neck Surgery, Faculty of Medicine, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, 113-8655 Tokyo, Japan.
Clin Neurophysiol. 2009 Mar;120(3):581-7. doi: 10.1016/j.clinph.2008.12.030. Epub 2009 Feb 10.
Cervical vestibular evoked myogenic potentials (cVEMPs) have been found to be useful for clinical testing of vestibular function. Recently, investigators showed that short-latency, initially negative surface EMG potentials can be recorded around the extraocular muscles (oVEMPs) in response to air-conducted sound (ACS), bone-conducted vibration (BCV), and head taps. Although these evoked potentials, which are located around the eyes, most likely originate primarily from the otolith-ocular pathway, the possibility of contamination by other nerve activities cannot be completely eliminated. The purpose of the present study was to clarify the origin of oVEMPs by examining these possibilities using clinical findings.
Twelve healthy subjects and 15 patients were enrolled. Of the 15 patients, 3 patients had undergone exenteration of the unilateral intraorbital contents, one had undergone exenteration of the right eyeball with preservation of extraocular muscles, 5 had facial palsy, and 6 had profound hearing loss. ACS and/or BCV were used in these subjects.
Exenteration of the unilateral intraorbital contents resulted in absence of myogenic potentials on the affected side. On the other hand, exenteration of the eyeball with preservation of extraocular muscles did not have a major impact on the responses. There were no significant differences in the waveforms between healthy subjects and patients with facial palsy or profound hearing loss.
The results suggested that short-latency, initially negative evoked potentials recorded below the eyes are not affected by cochlear or facial nerve activities and are dependent on the presence of extraocular muscles.
This study provides the evidence that oVEMPs originate from exraocular muscles activated through the vestibulo-ocular pathway.
已发现颈前庭诱发肌源性电位（cVEMPs）对前庭功能的临床检测有用。最近，研究人员表明，在眼外肌周围（oVEMPs）可记录到对气导声（ACS）、骨导振动（BCV）和头部轻拍产生反应的短潜伏期、初始为负的表面肌电图电位。尽管这些位于眼睛周围的诱发电位很可能主要起源于耳石 - 眼通路，但不能完全排除其他神经活动的干扰可能性。本研究的目的是通过利用临床发现检查这些可能性来阐明oVEMPs的起源。
招募了12名健康受试者和15名患者。在这15名患者中，3名患者接受了单侧眶内容物摘除术，1名患者接受了保留眼外肌的右眼球摘除术，5名患者患有面瘫，6名患者患有重度听力损失。这些受试者使用了ACS和/或BCV。
单侧眶内容物摘除导致患侧肌源性电位缺失。另一方面，保留眼外肌的眼球摘除术对反应没有重大影响。健康受试者与面瘫或重度听力损失患者之间的波形没有显著差异。
结果表明，在眼睛下方记录到的短潜伏期、初始为负的诱发电位不受耳蜗或面神经活动的影响，并且依赖于眼外肌的存在。
本研究提供了证据表明oVEMPs起源于通过前庭 - 眼通路激活的眼外肌。
