ARE DEFICITS IN THE EQUILIBRIUM SYSTEM RELEVANT TO THE CLINICAL INVESTIGATION OF SOLVENT-INDUCED NEUROTOXICITY

Objectives The diagnosis of solvent-induced chronic toxic encephalopat hy is commonly based on case histories of exposure to solvents, sympto ms, and deficits on psychometric tests. It has previously been demonst rated that long-term solvent-exposed workers have disturbances of the equilibrium system. The correlation between these disturbances and the diagnosis of chronic toxic encephalopathy has been analyzed in the pr esent study. Materials and methods Sixty men, consecutively admitted d ue to the suspicion of this syndrome, were investigated and classified into 3 groups - solvent-induced chronic toxic encephalopathy, incipie nt chronic toxic encephalopathy and nonchronic toxic encephalopathy. T hey were all examined using an otoneurological lest battery, including analysis of saccades, smooth pursuit, visual suppression of the vesti bular ocular reflex, and dynamic posturogaphy. Results Compared with h ealthy referents several of the subjects, even in the nonchronic toxic encephalopathy group, showed a reduced visual suppression ability, a prolonged latency of saccades, and pathological posturographic results . Some otoneurological tests correlated with the duration of exposure and the results of psychometric tests representing memory and perceptu al skills. Nevertheless, there was no significant group correlation be tween the otoneurological findings and the diagnosis of chronic toxic encephalopathy. Conclusion Disturbances revealed by an otoneurological investigation have so far not been considered in the diagnosis of chr onic toxic encephalopathy. Our results indicate that an otoneurologica l test battery adds worthwhile information about lesions within the br ainstem-cerebellar complex not revealed by a psychometric investigatio n.