When S1 and S2 were given simultaneously by gradually increasing the S1 intensity, CMAP(M) disappeared as the antidromic impulse from S1 became large enough to eradicated the proximal impulse from S2.

• 应用碰撞技术，同时刺激肘部正中神经及腕部尺神经，当腕部刺激强度逐渐增加后，可使得肘部正中神经引起之运动电位因碰撞而消失。