Pain perception in man after long term spinal cord stimulation.

Thresholds of non-painful and painful perception for electrical stimuli are not altered significantly during dorsal column stimulation either in the area of induced paresthesia or outside it. After long term stimulation of the dorsal column the thresholds for stimuli are significantly higher within the area of induced paresthesia but not outside it. Median nerve evoked somatosensory cortical potentials are not altered by conditioning or simultaneous DC stimulation. During DCS in three of eight patients only the vibration evoked cortical potentials were attenuated in the early three components of the potential.