Objective: The present study was to compare the frequency characteristics of bone- conducted vibration (BCV) and air-conducted sound-induced ocular vestibular evoked myogenic potential(oVEMP) with different stimulation settings, so as to select an optimal setting. Methods: Bruel and Kjaer artificial mastoid was used to calibrate bone vibrator, the mini-shaker. The outputspectrum and transient waveform were recorded when the input frequency was set at different frequencies and data were further analyzed to get the peake quivalent force level value of the output vibration. oVEMP was recorded as we previously reported with normal young adults. Response prevalence, latency, wave interval, amplitude, amplitude ratio, and bilateral amplitude asymmetry ratio were recorded and analyzed. SPSS 24.0 software was used for statistical analysis. Results: Output peak equivalent force level increased as the intensity of primary input stimulation increased at certain frequency,while it decreased as the frequency of primary input stimulation increased at certain intensity. Peak equivalent force level of 500 Hz tone burst (1-2-1) input stimulation was greatest as 139.8 dB when using mini-shaker for vibration stimulation,even greater when using bone conductor B-71.Twenty subjects were elicited with normal oVEMP with N1 and P1 waves in both ears using air-conducted stimulation or bone-conducted vibration.The response rate in these subjects was 95% and 100% respectively. The latency of N1 was (11.33±1.35) ms and (10.14±0.38) ms, latency of P1 was (16.24±1.56) ms and (15.65±1.19) ms, interval N1-P1 was (4.59±1.26) ms and (5.55±0.81) ms, symmetry coefficient was 12.22%[5.50%,21.85%] and 8.74%[3.37%,14.08%], amplitude was 3.07[2.05,4.43] μV and 3.07[2.05,4.43] μV in sound and bone conducted vibration group, respectively. The latency of N1, latency of P1, interval N1-P1, symmetry coefficient and n1-P1 amplitude of BC-oVEMP were different statistically (all P<0.05). Conclusions: 500 Hz 45 dB input stimulation setting is the optimal parameter for BC-oVEMP. BC-oVEMP can be recorded simply, safely and quickly in normal young people, thus it is a clinically practical way of measuring utricular function.
目的： 探索利用骨导耳机振子、激振器输出振动直接刺激颅骨记录眼肌前庭诱发肌源性电位（bone conducted ocular vestibular evoked myogenic potential, BC-oVEMP)，为BC-oVEMP的临床应用提供最理想的振动刺激参数；比较骨导振动刺激和气导声刺激引出电位波形的参数差异。 方法： 2017年3—5月，选取空军军医大学第一附属医院耳鼻咽喉头颈外科招募的健康志愿者共20名，其中男10名，女10名，年龄20~25（22.05±2.01）岁。声学分析仪采集骨导耳机振子、激振器的输出振动刺激的信号频谱和瞬态波形，依据国际标准计算得到输出的振动作用力的峰值等效力值（peak-to-peak equivalent force level，peFL）。分析选择可以获得稳定骨导振动刺激的最优参数。20名志愿者同时接受最大输出强度的气导声刺激、振动力刺激，记录双侧oVEMP波形及N1潜伏期、P1潜伏期、振幅等参数。数据采用SPSS 24.0统计学软件分析，正态分布两组间数值方差齐采用t检验，不齐则采用校正t检验。偏态分布两组间数值比较采用Mann-Whitney U检验。 结果： 不同频率的原始声刺激信号经声学分析仪记录到输出振动刺激的时域波形图、频谱图，输出振动的峰值频率与原始声信号频率一致。相同的原始信号强度时，500 Hz信号对应的频谱图输出峰值最高。原始声刺激参数频率相同时激振器的输出振动刺激的峰值等效力值随刺激声强度增加而增加，相同强度时激振器的输出振动刺激的峰值等效力值随频率增加而减小；以500 Hz短纯音输出的峰值等效力值最大，为139.8 dB peFL；同时大于相同原始声刺激信号时通过骨导耳机振子输出的峰值等效力值130 dB peFL。40耳中5耳在气导声刺激下未记录到对侧oVEMP电位波，即气导刺激和骨岛刺激的N1-P1波引出率分别为87.5%（35/40）和100%（35/40）。气导声刺激和骨导振动刺激N1的潜伏期分别为（11.33±1.05） ms和（10.14±0.38） ms，P1潜伏期分别为（16.24±1.56） ms和（15.65±1.19） ms，波间期分别为（4.59±1.26） ms和（5.55±0.81） ms，左右耳对称性系数分别为12.22%[5.5%,21.85%]和8.74%[3.37%,14.08%]，振幅分别为3.07[2.05,4.43] μV和11.96[7.42,14.75] μV；N1潜伏期、P1潜伏期、波间期、振幅值差异均有统计学意义（P值均<0.05）。 结论： 500 Hz短纯音原始刺激经激振器获得振动输出能最大，优于B-81骨导耳机振子；与传统气导声刺激相比，BC-oVEMP的引出率更高，波形幅度更大，更稳定可靠，更具临床应用价值。.
Keywords: Bone conduction; Utricle; Vestibular evoked myogenic potential; Vestibular function tests; Vibration.