Digital nerve conduction velocity as a sensitive indication of peripheral neuropathy in vibration syndrome

Digital nerve conduction velocities in the median and ulnar nerves were measured in order to obtain a more accurate indication of peripheral nerve impairment induced by hand-arm vibration. The subjects were 26 patients with vibration syndrome and 28 healthy controls, both groups of about the same age. Two pairs of surface electrodes were attached to the finger and one pair was positioned on the palm, while electrical stimulation was applied to the nerve at the wrist and elbow. Then sensory nerve conduction velocities were antidromically measured within the finger, and also from the wrist to the palm and from the elbow to the wrist. Slowed conduction within the finger was mostly found among the patients. The slowing was also encountered from the wrist to the palm across the carpal tunnel. Abnormalities were observed in the digital nerve segment in about 50-70% of the patients, and in the wrist-to-palm segment in about 10-25% of them. The present study indicates that digital nerve impairment predominantly occurs in the vibration-exposed patients, and that measurement of digital nerve conduction velocity can be a useful objective means to detect peripheral neuropathy in vibration syndrome.