Exploratory electromyography in the study of vibration-induced white finger in rock drillers.

Abstract

Electrophysiological observations made in the hands of a group of 16 rock-drillers were compared with 15 controls. Motor and sensory conduction velocities in the median and ulnar nerves together with the latency, duration, and the amplitude of the evoked action potentials were measured. The differences between the groupswere statistically significant mainly in latency, duration, and amplitude, especially of the sensory action potentials. Measurement of the conduction velocities, in general, proved to be less sensitive, and the only significant change observed was in the sensory conduction velocity in the median nerve when the first digit in the right hand was stimulated. The most interesting result was evidence of an increased prevalence of possible carpal tunnel syndrome in the exposed (44 % compared with 7 % in the control group). A similar set of data, but exclusively sensory and not standardised for age and sex, was obtained from 25 university students for comparison with the assigned groups. The results showed that apart from sensory duration the control group had values that were closest to the students while the vibration group had values furthest away.

Vibration-induced neuropathy. Detection by nerve conduction measurements.

“…Although significant decreases in conduction velocity have frequently been found, on the average, in the sensory and motor nerves of vibration-exposed workers, when compared with referents, no such reductions have been reported in some investigations. In these studies the changes, if any, have been restricted to reduced sensory action potentials, sometimes accompanied by increased motor distal latency (1,8). The inconsistency of the findings in table I is, at first sight, disturbing.…”

“…This lack of consistency does, however, suggest a procedure for evaluating the data, namely, a detailed analysis of those investigations that systematically explore peripheral nerve conduction, with particular reference to the exclusion of neuropathies unrelated to vibration exposure and the selection of appropriate reference groups. To enable a direct comparison to be made between the results of the five studies, the data of Chatterjee et al (8), for individual fingers, and those of Chatterjee et al (8) and Torii et al (18), for left and right hands, need to be combined into one value for both hands, as do those of Juntunen et al (12) for the two vibrationexposed subgroups. This is done by forming the mean value M and standard deviation S from m data sets using:…”

Clinical neurological methods in the diagnosis of the hand-arm vibration syndrome.

“…Carpal tunnel syndrome has been reported to occur more often among vibration-exposed workers than in a normal male population (4,6). The clinical picture of carpal tunnel syndrome that is induced by vibration slightly differs from carpal tunnel entrapment of other origin.…”

Clinical aspects of the hand-arm vibration syndrome. A review.

“…Knowledge in this field is, however, increasing and presumably a more useful test will eventually be developed (17,19,87).…”