Analysis of Nerve Electromyogram among 20 Workers Exposed to Hand-transmitted Vibration

Objictive To study the adverse effects of hand-transmitted vibration on peripheral nervous functions. Methods The NCV(nerve conduction velocity) and EMG(electromyography) were examined in 20 workers exposed to hand-transmitted vibration and 30 healthy adults without any exposure to occupational hazard served as the control group. Results①The motor nerves examination showed that there were 85%workers with prolongation of the distal latency of median nerves and 35%workers with reduction of MCV(motor-nerve conduction velocity)(P0.01)②The sensory nerves examination showed that the rednction of SCV(sensor-nerve conduction velocity) of median and ulnar nerves was 40%and 30%(P0.01).respectively.③The EMG showed that the polyphasic potential of 42.5%workers increased when contracted with little strength.15%workers showed the fibrillation potential in silence.(P0.05 or P0.01). Conclusion The peripheral nervous function of workers exposed to hand-transmitted vibration was damaged obviously.The earliest manifestation of nerve electromyogram was prolongation of the distal latency of median nerves.The reduction of NCV was observed and the motion and sensory nerve were aeffected with aggravation of damage.