Stimulus artifact reduction in nerve conduction.

Techniques recommended to reduce stimulus artifact (SA) include modifications of electrodes, electrode contact, and stimulus circuitry. Twenty-two subjects were studied to evaluate two electrode positioning techniques to reduce the SA in sensory nerve conduction velocity recordings. In 16 normal subjects, rotating the stimulator anode around the cathode 70-105 degrees flattened the baseline and permitted recording a clear take-off of the sural evoked response. In the remaining six subjects, other angles were optimal. Reconfiguring location of the reference and ground electrodes to increase common mode rejection was not consistently effective in reducing the SA in the eight patients tested. Isopotential lines produced by the stimulator electric dipole are described to explain the findings. This technique is simple and effective in reducing SA.