Figure 7. Median nerve CMAPs at different temperatures are elicited at constant MC stimulator output intensity (50 %).

Superimposed responses at two temperatures elicited by the different waveforms are shown in the bottom records. Temperature was measured at the skin surface. Cooling was obtained by packed ice, which required removal and then repositioning of the MC. At 33 °C, pull-down is absent. At 22 °C, latencies are prolonged and pull-down is present but diminishes as warming occurs.