Peripheral nerve stimulation inhibits nociceptive processing: An electrophysiological study in healthy volunteers

Objectives. Electric peripheral nerve stimulation (PNS) is a neuromodulatory therapy in pain patients. The efficacy of this neurosurgical pain treatment is controversial because its antinociceptive effect in humans has not been objectively proven so far. Materials and Methods. Noxious infrared laser stimulation of the left hand dorsum evoked cortical potentials (LEP) by selective excitation of A delta-fiber nociceptors in 15 healthy volunteers under control and PNS conditions. LEP were recorded before, during, and after electric A beta-fiber stimulation (PNS) of the left superficial radial nerve. In the control session LEP were recorded without PNS. Laser stimulus intensity ratings, LEP latencies, and amplitudes were statistically analyzed (ANOVA). Results. During PNS, LEP amplitudes (p < 0.001) and laser intensity ratings (p < 0.05) significantly decreased, and LEP latencies significantly increased (p < 0.05). Under control conditions LEP and intensity ratings remained unchanged. Conclusions. The electrophysiologic data provide evidence that electric stimulation of peripheral A beta-fibers reliably suppresses A delta-fiber nociceptive processing in human volunteers.