Pain-Related Evoked Potentials in Normal subjects and Patients with persistent pain after spinal surgery

Our final purpose is to investigate the pathway of pain in patient with persistent pain after spinal surgery. This time we recorded a pain related potential for normal subjects and patients with persistent pain after spinal surgery stimulating skin surface electrode Inui developed. Target is 21 normal subjects and 6 patients with persistent pain after spinal surgery. We stimulated index finger and second toe at random using intra epidermal electrical stimulation. The evoked potentials were recorded from Cz. During the patients, we recorded from 16 painful legs. In normal subjects, the latency of upper leg stimulation is significantly faster than that of lower leg stimulation. And there was not significant difference in N1 and P1 latency of upper, lower leg between patients and normal subjects. But the N1 and P1 amplitude in patient with persistent pain after spinal surgery decreased compared with normal subjects. There is possibility of this potential contributing to activity of temporal lobe and cingulate gyrus, ability of calculation for pain and emotion.