Electromyographical Neuromuscular Synapse Testing and Neurological Findings in Workers Exposed to Organophosphorous Pesticides

Abstract

The purpose of this study was to evaluate electromyographic neuromuscular synapse testing and neurological examination for early detection of organophosphorous pesticides intoxication. Two groups of healthy agricultural workers and one group of healthy spraymen were exposed to various organophosphorous pesticides of different intensities. An additional group of nonexposed agricultural workers was also analyzed for comparative purposes. Before and during exposure, cholinesterase activity was determined. Personal, occupational, medical, and neurological case histories were taken; during the same session electromyographic synapse testing was performed and neurological information was recorded. No significant difference between exposed groups and the control group was found. The electrically evoked muscle potential series in exposed workers remained as constant as those recorded for the control group. The frequency of different types of amplitude changes was the same in exposed groups and in the control group. Neurological records showed no significant deviations from normal for exposed workers.

Changes in muscle action potentials described were, therefore, attributed tofactors outside the synapse. Changes could have been due to differences in the distance between the recording electrode center and the electrical source. A decrease in the amplitude of evoked potentials due to real neuromuscular synapse insufficiency must always be accompanied by a more or less clear reduction of muscle strength—a well-known fact established by many neurological and pharmacological studies.

ESectromyographical synapse testing and clinical neurological examination are not sensitive enough for early detection of latent pesticide(s) intoxication. Other tests— especially biochemical ones—should be investigated for early detection of latent intoxication.