Acute behavioral effects of exposure to some organic solvents -psychophysiological aspects

Acute low-level exposure to organic solvent vapours may result in prenarcotic states of CNS-depression, often characterized by behavioral dysfunction. Behavioral findings from experimental acute human exposures to toluene, trichloroethylene (TCE), and methylene chloride (MC) are covered in this review. Perceptual measures (e.g. critical flicker fusion = CFF), measures of sustained attention (vigilance), measures of psychomotor performance (as e.g. reaction time, motor speed, coordination) as well as EEG-measures (sensory evoked potentials) are used to illustrate the main effects from such studies. Progressive increase of reaction time was observed at toluene-exposures of only 300 ppm (30 minutes). No consistent behavioral deficit has been reported for trichloroethylene below 300 ppm; instead, visual and auditory evoked potentials were found to be affected at TCE vapour-concentrations between 50 and 100 ppm (3 1/2 - 7 1/2 hours of exposure). CFF-depression, vigilance-decrement and disruption of psychomotor performance has been observed during MC-exposure (200 - 800 ppm; 2-4 hours). Although such behavioral effects are usually considered reversible and of no demonstrated pathological impact, they may nevertheless contribute to accident-prone behavior in occupational settings.