Study of sensation and muscle twitch responses to spinal cord stimulation.

Electrically induced sensation and muscle twitches were studied in a group of 43 patients in whom epidural electrodes were percutaneously placed for the evaluation of the effect of spinal cord stimulation on modification of their impaired motor control. Mean stimulus strength for sensory threshold was 5.25 +/- 2.75 mA and the tolerance level was at the stimulus strength of 10.8 +/- 4.4 mA. Muscle twitches with short latencies were recorded in limb and trunk muscles within the segments at the stimulating cathode. Exceptionally, higher stimuli elicited muscle twitches of distant segments.