[Effect of organic solvents on the central nervous system]

Psychological tests and EEG investigations were applied for detecting early signs of neurotoxicity of organic solvents present in glues used in the production of shoes (extraction benzin, toluene and n-hexane). In 5% of the obtained samples the permissible benzin concentration was exceeded, and in 10% of samples this permissible concentration of toluene was exceeded. Psychological testing was done in 100 subjects. The intelligence level was at the lower normal range. Organic cortical changes were demonstrated in 35 cases, and borderline pathological changes in 28 cases. The test of L. Bender suggested damage to the occipital cortex in 31, and the Graham-Kendal test demonstrated abnormalities in 13 cases. EEG was done in 56 subjects in this group and in another 9 subjects with a high concentration of toluene metabolite. In 75.4% of subjects the EEG findings were classified as normal, within normal limits or borderline normal. Abnormal EEG tracings were found in 24.0%. Diffuse, slight or moderately intense abnormalities were present in 7 cases, focal abnormalities in 4 and seizure activity in 7. Most subjects with abnormal EEG findings worked under conditions of excessive exposure, with the summarized exposure index exceeding the acceptable one. No correlation was demonstrated between cortical pathological changes and the degree of occupational exposure and the type of EEG tracings. The authors suggest that organic occipital cortical changes may be regarded as an early phase of organic brain damage syndrome and disturbances of cerebral bioelectric activity as a sign of individual biological response to chronic action of organic solvents on the organism.