Estimation of conduction velocity of Aδ fibers using heat-pain related somatosensory evoked potentials in humans

The authors´ study evaluated the utility of a contact thermal stimulator in determination of conduction velocity (CV) of small cutaneous fibers subserving thermal pain (nociception) sensitivity in humans. The stimulator delivers a brief duration, fast rise-time heat pulse to the skin without contamination of other sensory modalities. Pain somatosensory evoked potentials (SEPs) to thermal stimuli were digitally filtered, selectively averaged and Woody filtered to improve their signal-to-noise ratio. The CV of Aδ fibers was estimated from the difference of the peak latencies of the arm and leg cortical potentials. The authors´ studies show that the CV from these SEPs is consistent with their arising from Aδ thermal nociceptors