Dorsal column stimulation. Its effect on the somatosensory evoked response.

Several authors have shown that dorsal column stimulation (DCS) modifies appreciation of pain. We studied the effects of DCS on the somatosensory evoked response (SER) in six subjects. Somatosensory evoked responses to stimulation of the tibial nerve and effects of varying frequencies and intensities of DCS on SER components were recorded. During DCS there was attenuation of late SER components with little effect on early components. Stimulus intensities greater than necessary to relieve pain suppressed all SER components. Our findings suggest that the minimal effective DCS variables to relieve pain are those that produce selective suppression of late SER components.