SURVEILLANCE OF EARLY NEUROTOXIC DYSFUNCTION

Surveillance of early neurotoxic alterations was undertaken in 3 reinf orced plastics plants, with a view to preventive intervention. Using a longitudinal study design, exposure parameters (environmental styrene in the respiratory zone of each worker and end-shift mandelic acid (M A)) and neurobehavioral performance (Neurobehavioral Core Test Battery and Field Assessment: Sensory Tests), were assessed at time zero (T-0 ); recommendations were made to reduce exposure at jobsites with the h ighest risk. Reassessment was made two years later (T-2). Complete exp osure data was available for 118 workers at T-0; 75 were still employe d at T-2; of these, 57 (76%) returned for testing. Those who returned had more seniority (p<0.001) and higher MA (p<0.01) and styrene (p<0.0 5) levels at T-0 than the others. Analyses, performed on the T-0-T-2 d ifferences, showed improvement in exposure parameters in Plant 3, wher e lower levels were observed at T-2 for styrene (p<0.05) and MA (p<0.0 01). Workers in Plant 3 (n = 29) performed better (p<0.05) at T-2 for short term memory, perceptuo-motor speed, motor precision and manual d exterity; they reported more vigor (p<0.05) and less anger (p = 0.07). This was not the case for the workers from the other plants. Generall y, the T-0-T-2 difference in MA was associated (Spearman's Rho) with d ifferences in color vision (p<0.001), simple reaction time (mean and s tandard deviation), digit span forward, tension, fatigue and the numbe r of symptoms (p<0.05); aiming precision showed a similar tendency (p< 0.10). These findings suggest that group surveillance of early nervous system changes for jobs with exposure to neurotoxins, using a sensiti ve neurofunctional test battery, may be useful for preventive interven tion. (C) 1996 Intox Press, Inc.