Determination of the distribution of nerve conduction velocities in chain saw operators.

By measuring the distribution of conduction velocities (DCV) in sensory fibres of the median nerve, the effects of local vibration on all faster and slower large myelinated nerve fibres were examined in 10 male chain saw operators (three operators had frequent attacks of white finger; the attacks were only occasional in four and negative in three). All parameters of DCV, and conventional sensory nerve conduction velocity were significantly slowed in the chain saw operators. It is suggested that local vibration affects the faster and slower nerve fibres; parameters of the DCV are sensitive indicators of both the neurological and vascular effects.