噪声短时暴露所致的耳蜗电位改变

本实验观察115dB(SPL)白噪声暴露20min对豚鼠耳蜗直流电位(EP),复合听神经动作电位(CAP),微音器电位(CM)的影响。发现此种噪声暴露确可提高源于血管纹的正EP(P-EP),说明有血管纹功能的代偿性增强;而负EP(N-EP)变化不大。AP及CM输入-输出函数的变化说明噪声首先影响外毛细胞的主动运动功能。EP与耳蜗电图的对照分析表明,血管纹功能的改变确能影响噪声性听损伤的发展。

CHANGES IN COCHLEAR POTENTIALS INDUCED BY BRIEF EXPOSURE TO INTENSE NOISE

Changes in endocochlear potentials (EPs), cochlear microphonics (CM) and compound action potential (CAP) of 8th nerve were investigated correlatively in guinea pigs before, during and after a brief exposure to 115 dB(SPL) white noise. The negative component of EP (N-EP) was induced by anoxia at different time points of the noise exposure. It was found that the noise significantly raised the positive EP (P-EP) which is considered to account for the changes in the function of stria vascularis, while no obvious change in N-EP was observed. The noise exposure induced a great threshold shift in CAP and an increase in its maximal output. In CM, how- ever, a little threshold shift and a remarkable decrease in the maximal output were found after the same noise exposure. These results indicate that the changes of stria Vascularis function do happen and play a certain role in the development of noise-induced hearing loss, and the ability of active movement of outer hair cells was firstly impaired by the noise.