Sensory nerve conduction velocities of median, ulnar and radial nerves in patients with vibration syndrome.

OBJECTIVE: The present study aimed to clarify the range of involvement for hand-arm vibration syndrome (VS) in the median, ulnar and radial nerves of the hand.

METHODS: Sensory nerve conduction velocities (SCVs) for 3 nerves in the hands and arms were examined for 34 patients with VS and 23 age-matched controls. Neuropathy types were classified by possible carpal tunnel syndrome (CTS), Guyon's syndrome and digital neuropathy in three nerves.

RESULTS: SCV in the median nerve (middle finger, wrist-elbow) and ulnar nerve (little finger, wrist-elbow), and amplitudes of the median nerve (wrist-proximal and distal parts of the middle finger), ulnar nerve (wrist-proximal and distal parts of the little finger; forearm-proximal part of the little finger; upper arm-proximal part of the little finger) and radial nerve (dorsal side of the hand-thumb) were significantly reduced in VS patients compared with controls. According to subject classifications based on the results of SCV and amplitude of nerve action potential, 52.9% of VS patients displayed multi-focal neuropathy including digital neuropathy, possible CTS and/or Guyon's syndrome.

CONCLUSION: These findings suggest that VS affects all three nerves in the hand. According to classification results, the main disorders of peripheral nerves comprise digital neuropathy.