豚鼠不同部位引导的40Hz相关电位特点的对比

Comparison between 40Hz potential from vertex and 40Hz potential from round window in guinea pigs

目的：对比观察从豚鼠不同部位引导的40Hz相关电位的特点，为临床低频听力检测提供适宜指标。方法：采用适宜的参数即带通滤波为8-30Hz，刺激间隔为25ms，扫描时间为100ms从豚鼠的颅顶和圆窗同步记录听觉中潜伏期40Hz相关电位和听觉早潜伏期40Hz相关电位（40Hz AERP-MLR和40Hz AERP—ELR）。结果：两种电位的共同特点是频率响应好，波形稳定，易辨认。圆窗的40Hz AERP-ELR较颅顶的振幅高，反应阈值低，特别是低频的反应阈值低，在0．5kHz短纯音时听阈可达到（14．15±6．06）dBnHL。而颅顶40Hz AERP-MLR的反应阈值则是（43．50±9．65）dBn HL，明显高于圆窗反应阈值（P〈0．01）。结论：经圆窗引导的40Hz AERP—ELR在低频听力检测中优于颅顶，为临床低频听力检测提供一项较好的客观指标。

Objective To compare the characteristics between two kinds of 40Hz auditory evoked potentials and provide suitable index for clinical auditory test of low-frequency. Methods The potentials including 40Hz auditory event related potential of middle latency response （40Hz AERP-MLR） and 40Hz auditory event related potential of early latency response （40Hz AERP-ELR） from window and vertex were recorded in guinea pigs. Results The common characteristics of the potentials were good frequency response, easy identification and lower responsive thresholds. Amplitude of 40Hz AERP-ELR was higher and threshold was lower than 40Hz AERP-MLR, especially 0.5kHz tone burst, which was （14.15±6.06） dBnHL. In vertex, the threshold of 40Hz AERP-MLR was （43.50±9.65） dBnHL, which was higher than that in round window （P〈0.01） . Conclusion 40Hz AERP- ELR recorded from round window is better than from vertex in low-frequency test. The experiment results indicate that the responses provide ideal index for clinical auditory test of low-frequency.