M. Niklasson et al., ARE DEFICITS IN THE EQUILIBRIUM SYSTEM RELEVANT TO THE CLINICAL INVESTIGATION OF SOLVENT-INDUCED NEUROTOXICITY, Scandinavian journal of work, environment & health, 23(3), 1997, pp. 206-213
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.