NEUROTOXICITY INDUCED BY EXPOSURE TO TOLUENE - AN ELECTROPHYSIOLOGIC STUDY

The object of the present study was to evaluate, with the aid of electrophysiologic techniques, the alterations induced in the auditory nervous system by exposure to toluene in a group of rotogravure workers. From 300 workers who were apparently in good health but were professionally exposed to toluene, we selected a sample of 40 workers of normal hearing ability. They were examined with an adaptation test studied by the brainstem auditory evoked potential technique with 11 and 90 stimulus repetitions a second. The results were compared with those in a group of workers of the same age but not professionally exposed to solvents. Our study demonstrates that exposure to toluene is able to induce a statistically significant alteration in the electric responses with both 11 and 90 stimuli repetitions. This alteration can be explained as a toluene exposure-induced modification, of physiologic stimulus conduction mechanisms, even in the absence of any clinical sign of neuropathy. Furthermore, such a modification could be observed in the electric responses of the entire auditory system, from peripheral receptors to brainstem nuclei.