Monitoring neurotoxic effects among laboratory workers exposed to organic solvents

The relationship between organic solvent exposure and central nervous disorders make early detection of neurophysiologic et neuropsychologic alterations in organic solvent exposed workers a priority. Moreover the variability in the frequency of exposure and the numerous organic solvents encountered in scientific laboratories render the environmental and biological measurements used in medical surveys almost impossible. The present study was undertaken to appreciate the potential neurotoxic effects of organic solvents handling in laboratory employees. Neurophysiological and neuropsychological tests batteries were used with each worker and data were adjusted for potential confounding factors (age and education level), A Principal Components Analysis was performed to reduce the information and the first five factors corresponded to mood states, speed coding, contrast vision in high frequencies, manual dexterity and contrast vision in low frequencies. These five factors were compared between the daily manipulators of at least one solvent (n=75) and the non or occasional solvent users (n=35). The results from this study showed that subjects directly in contact with solvents had a poorer mood state than those who were not or rarely exposed (p<0.01) and that independently of the ''work activity''. Mood state impairment in chronic solvent exposed workers has been shown by many authors, with or without psychomotor alteration, and may reflect possible over-exposure. Detection of this instability may lead to early neurophysiologic alteration in exposed workers and permit health services to intervene before the development of irreversible effects.