K. Yokoyama et al., POSTURAL SWAY FREQUENCY-ANALYSIS IN WORKERS EXPOSED TO N-HEXANE, XYLENE, AND TOLUENE - ASSESSMENT OF SUBCLINICAL CEREBELLAR DYSFUNCTION, Environmental research, 74(2), 1997, pp. 110-115
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.