Table 2.

Onset latency of MEP peaks

MEP peak	Onset latency (ms)				P-value
	Controls, 0.05 mV	Controls, 1.0 mV	Controls, 3.0 mV	SCI, 1.0 mV
First	0.90 ± 0.13	1.09 ± 0.11	1.11 ± 0.11	1.14 ± 0.12	<0.001
Second	2.66 ± 0.18	2.40 ± 0.17	2.37 ± 0.22	2.60 ± 0.17	<0.01
Third	4.97 ± 0.44	4.08 ± 0.29	4.06 ± 0.26	4.41 ± 0.37	<0.001

Note: Values are mean ± SD onset latency of MEP peaks for test stimulus (S1) intensities of 0.05, 1.0, and 3.0 mV in controls and 1.0 mV in SCI subjects. P-values represent ANOVA tests performed across S1 intensities on each MEP peak. Note that a decrease in the S1 intensity (∼0.05 mV) in controls delayed the onset latency of the second and third peaks compared with higher S1 intensities (1.0 and 3.0 mV), whereas the delay of the third but not the second peak seen after SCI was less than controls at lower S1 intensity (∼0.05 mV).