正常和卡那霉素中毒豚鼠听觉脑干诱发反应及频率跟随反应的比较研究

通过测定阈值和频谱分析,比较了正常和卡那霉素中毒后豚鼠听觉脑干反应(ABR)及频率跟随反应(FFR)的特性.正常FFR的非线性随刺激频率的减低而增加,表现为高次谐波的出现.从频谱中基频成分的峰很容易识别FFR阈值.卡那霉素作用后,高频FFR首先受到影响,波幅下降,阈值显著升高.低频FFR受到影响较小.同一动物ABR阈值尚未变化时高频FFR的基频峰值已下降,乃至消失.实验结果表明FFR对耳毒性药物中毒反应由于其包含有频率特性比ABR更灵敏,更便于定量分析.

A COMPARISON BETWEEN AUDITORY BRAINSTEM EVOKED RESPONSES (ABRs) AND FREQUENCY FOLLOWING RESPO SES (FFRs) IN NORMAL AND ABNORMAL GUINEA PIGS

A comparison between Auditory Brainstem Evoked Responses (ABRs) and Frequency Following Responses (FFRs) in normal and Kanamycin treated Guinea Pigw was made using threshold detection and spectrum analysis. The nonlinearity of FFRs became distinct as the stimulus frequency decreasd. An analysis of the data with Fast Fourier Trans-formation indicated that there was a primary peak wuth several other peaks at harmonic frequencys below 640Hz. We could easily identiky the thresholds of FFRs by the primary peak (its amplitude higher by 10 dB than that of backgroung noise) After medication of Kanamycin, the FFRs to high frequency sound stimulus were affected frist, with decreased amplitude and markedly increased threshold; whereas the FFRs to lower frequency sound stimulus were less affected. The amplitude of primary peaks of FFRs decreased significanyly or even no primary peaks could be seen for higher frequency stimuli. While the ABR thresholds still had no visible change. It suggests that the FFRs might be a more sensisive indicator than ABR in that case.