刺激声强度对气导短纯音诱发的眼肌和颈肌前庭诱发肌源性电位的影响

Effect of acoustic stimulus intensity on air-conducted sound elicited ocular vestibularevoked myogenic potential and cervical vestibular-evoked myogenic potential

目的：了解刺激声强度差异对正常人气导短纯音诱发的眼肌前庭诱发肌源性电位（ocular vestibular-evoked myogenic potential, oVEMP）和颈肌前庭肌源性诱发电位（cervical vestibular-evoked myogenic potential, cVEMP）的影响。方法选择国人正常人35例作为研究对象，男16例，女19例，年龄4~40岁（20.80±8.89），以500Hz tone brust为刺激音，按照100、95、90、85、80、75 dB nHL依次进行气导oVEMP和cVEMP检测，计算VEMP在不同刺激声强度的引出率、nI潜伏期、pI潜伏期、nI-pI波间期、振幅值和AR值，进行波形参数计算和声强度组间对比。结果全组正常人oVEMP和cVEMP的阈值分别为86.5±4.37 dB nHL、83.57±4.52 dB nHL。随着刺激声强度的减弱，无论oVEMP还是cVEMP，均表现出引出率下降、振幅减低等特点。在刺激声强度为100 dB nHL和95 dB nHL时，oVEMP和cVEMP的引出率均为100%，两者之间图形参数差异并不显著。结论随着刺激声强度的减弱，oVEMP和cVEMP出现引出率下降、振幅减低的趋势。对于40岁以下的国人人群，建议采用95 dB nHL作为VEMPs测试的最大起始刺激强度。

Objective To observe the effect of acoustic stimulus intensity on air-conducted sound elicited ocular vestibular-evoked myogenic potential （oVEMP） and cervical vestibular-evoked myogenic potential （cVEMP） in normal young Chinese subjects. Methods Thirty-five normal subjects aged 4-40 years （20.80 ± 8.89 years）, including 16 males and 19 females, were recruited for conventional oVEMP and cVEMP examinations. The responses obtained from each side using 500 Hz tone bursts were divided into 6 groups according to different sound intensities （100, 95, 90, 85, 80 and 75dB nHL）. The response rate and normal parameters of each stimulus intensity group were calculated. Results As the acoustic stimulus intensity decreased, the oVEMP response rate decreased from 100%in both 100 dB nHL and 95dB nHL groups to 97.14%（90 dB nHL）, 54.29%（85 dB nHL）, 14.29%（80 dB nHL）, and 2.86%（75 dB nHL）, and the response rate of cVEMP, 100%in both 100 dB nHL and 95dB nHL groups, was lowered to 97.14%（90 dB nHL）, 84.29%（85 dB nHL）, 38.57%（80 dB nHL） and 8.57%（75 dB nHL）. The response rate and the parameters were comparable between 100 and 95 dB nHL groups. Conclusion As the acoustic stimulus intensity decreases, both oVEMP and cVEMP show decreased response rate and amplitude. For Chinese subjects under 40 years of age, we recommend 95dB nHL as the maximum initial stimulus intensity in VEMPs test.