The neurotoxicity of polybrominated biphenyls: results of a medical field survey.

Neurologic symptoms were the earliest and most prominent symptoms recorded in Michigan farm residents exposed to PBB as compared to a non-PBB exposed control farm population in Wisconsin. In Michigan (particularly among males) those who exhibited the most marked symptoms tended to show diminished performance as assessed by special tests, although population differences in performance were not as marked. Low indices of performance were also significantly correlated with intake of home-produced foodstuffs, particularly during the years 1972--1974 and store-bought products during the years 1975--1976. Between 1972 and 1976 the Michigan farm residents studied made significant changes in their consumption patterns of products suspected to be contaminated with PBB, as compared to those of Wisconsin farm residents. Serum PBB levels were not found to be significantly higher in Michigan males and females exhibiting the most prominent neurologic symptoms. Serum PBB levels were negatively correlated with performance test scores, particularly in males in older age groups.