[A comparative study of the sensory conduction velocity of the sural nerve using surface and needle electrodes]

In 18 healthy persons aged 22-71 years and 17 patients suffering from clinically defined polyneuropathy the NCV of the sural nerve was measured both by antidromic technic recorded by surface electrodes and by orthodromic technique recorded by needle electrodes. Stimulation was done by bipolar surface electrodes in all cases. The skin temperature was warmed up to the minimum of 35 degrees C. The results showed in both groups a highly significant correlation of the NCV measured by antidromic and orthodromic technique. With increasing age the NCV decreased, but this was not significant. In all healthy persons sensory nerve potentials could be recorded with both techniques. In polyneuropathy missing of sensory potentials was higher in patients investigated by the antidromic technique than by orthodromic. For clinical practice measurement of NCV in sural nerve using antidromic technique should be preferred because of its simpler and faster achieving, its lower discomfort for the patient and avoiding risk of infection. However in case of missing nerve potentials, orthodromic investigation using needle electrodes for recording should be added.