POSTURAL SWAY FREQUENCY-ANALYSIS IN WORKERS EXPOSED TO N-HEXANE, XYLENE, AND TOLUENE - ASSESSMENT OF SUBCLINICAL CEREBELLAR DYSFUNCTION

To clarify the effects of organic solvents on the postural balance sys tem, 29 male sandal, shoe, and leather factory workers exposed to n-he xane, xylene, and toluene (solvent workers) were examined by computeri zed static posturography with sway frequency analysis. Concentrations of metabolites of solvents in urine samples taken from the workers in the morning before work ranged from 0.41 to 3.06 (mean, 1.20) mg/g cre atinine (Cn) for 2,5-hexanedione, from 0.10 to 0.43 (mean, 0.19) g/g C n for methylhippuric acid, and from 0.05 to 2.53 (mean, 0.37) g/g Cn f or hippuric acid; estimated concentrations of n-hexane in workplace ai r ranged from 13 to 100 (mean, 40) ppm. Control subjects were 22 healt hy males without exposure to solvents. With eyes open, postural sway w ith a frequency of 2-4 Hz in solvent workers was significantly larger than that in controls in the anteroposterior direction. With eyes clos ed, sway with a frequency of 0-1 Hz was significantly larger in solven t workers in the mediolateral and anteroposterior directions. Results of multiple regression analysis showed that with eyes open the 1- to 2 -Hz and 2- to 4-Hz sways were related positively to 2,5-hexanedione an d inversely with methylhippuric acid. The pattern of changes suggests that the vestibulocerebellar and spinocerebellar afferent systems are asymptomatically affected by n-hexane; the effect of n-hexane on the v estibulocerebellar system is possibly inhibited by xylene. (C) 1997 Ac ademic Press.