Nerve conduction in the hands of vibration exposed workers.

Symptoms of peripheral neuropathy in the hands are common among workers using vibrating tools. The mechanism for this and its relation to carpal tunnel syndrome (CTS) was studied in workers exposed to vibration at their workplace (17), along with a control group of healthy construction workers with heavy manual work but without vibration exposure (10). Patients with uni- or bilateral CTS (11) and a group of healthy volunteers without manual work (9) were included for comparison. Median nerve conduction velocities were measured both over the carpal tunnel and in a more distal segment. Vibration exposed workers had similar conduction velocities to unexposed construction workers. The subgroup of vibration exposed patients with symptoms from the hands had normal conduction in the ulnar nerve but demonstrated a decrease in median nerve conduction comparable (but less pronounced) with the CTS group. On a group basis these results indicated that the median nerve is most vulnerable for hand-arm vibrations. However, the conduction defects were not pronounced enough to diagnose CTS in most individual cases.