中文摘要：

目的 确定清晰的皮层诱发电位起始点，改进皮层诱发电位潜伏期的测量。方法 利用动物实验提取皮层诱发电位信号。将一种新的基于中值滤波的方法应用于皮层诱发电位潜伏期的测量。结果 广泛使用的叠加平均法对脑皮层诱发电位信号有平滑作用，使皮层诱发电位起始点难以确定。而提出的新的基于中值滤波的方法与传统的叠加平均法相比。能够得到清晰的皮层诱发电位起始点。对大鼠脑皮层诱发电位潜伏期的定量分析表明，不同的检测者应用新的基于中值滤波的方法测量的潜伏期比叠加平均方法得到的潜伏期明显一致。结论 新的基于中值滤波的方法能得到清晰的诱发电位起始点，从而避免了皮层诱发电位潜伏期测量中的人为误差。

英文摘要：

Objective To determine the clear onset point of cortical evoked potentials and improve the latency measurement. Methods Cortical evoked potential signals were extracted by animal experiment and a new method based on median filter was applied to measure their latencies. Results The most widely used method of averaging process had an effect of smoothing the edges of signals, which made it difficult to determine the onset potential of the averaged waveform. New method based on median filtering can give clearer onset point of evoked potential compared to the averaging method. Conclusion New method based on median filtering can avoid factitious error in latency measurement by giving clearer onset point.