Motor evoked potentials in somatosensory evoked potentials (SSEPs)

We studied the change of amplitude in Erb, lateral neck, N10, N13, and N20 potentials of somatosensory evoked potentials (SSEPs) by stimulating the median nerve at wrist or fingers. The N10 potential was not evoked clearly in any subjects by stimulating fingers, while N10 potential by stimulating wrist were evoked distinctly in all subjects. With this observation, evoked N10 potentials by wrist stimulation can be considered to reflect on the motor dominant nerve stimulation. In addition to this, with supramaximal stimulation the contributions of motor fibers were estimated as about 0.41+/-0.19 % of their amplitudes in Erb evoked potentials.