[Neurotoxicity of workplace substances. IV. Determination of motor and sensory nerve conduction velocity in persons exposed to solvent mixtures].

A cross-sectional study was performed on 112 workers with long-term exposure (mean 5 years) to a mixture of organic solvents (aliphatic and aromatic hydrocarbons, halogenated hydrocarbons). The purpose of the study was to examine whether this exposure had caused impairment of the peripheral nervous function. Forty-six workers with non-occupational risk of peripheral neuropathy (previous diseases, alcohol abuse, medication) were excluded. As a basis for the evaluation of solvent exposure, we carried out "environmental and biological monitoring" for some solvents. In no case did a hint of a manifest disorder of the nervous system exist. By comparison with age-matched controls, the mean sensory conduction velocity (NCV) of the N. ulnaris of the exposed persons was significantly reduced by 1.5 m/s. The maximal motor NCV of the N. ulnaris and the sensory NCV of the N. medianus did not differ significantly. The differentiation of the workers relating to short-(7-24 months), middle-(25-60 months)- and long-(more than 60 months) term exposure showed that the sensory NCV of the N. ulnaris was slowed only for persons with middle- and long-term histories of solvent exposure. Assessing the individual neurophysiological status the frequency of pathological NCV improved from 12 to 36% in relation to increasing time of exposure. Overall 15 of 66 workers (23%) had abnormal NCVs. The findings are discussed according to data given in literature.