Neurobehavioral estimation of children with life-long increased lead exposure.

A battery of neurobehavioral examinations was carried out on 30 children who were 6-11 yr of age and who had resided near a lead smelter all their lives. Their blood lead levels were 35-60 micrograms/100 ml and erythrocyte protoporphyrin levels were greater than 100 micrograms/100 ml. Neurological examination revealed that they had a significantly higher incidence of pathological findings (e.g., muscle hypotonia, increased tendon reflexes, dysarthria, and dysdiadochokinesia) than children from an unpolluted area who were matched for age, sex, family size, and educational and socioeconomic status of the parents, but who had normal erythrocyte protoporphyrin levels. The children with elevated blood lead levels showed, after assessment by the Oseretsky test, retardation of motor maturation; they also scored higher on the minimal brain damage scale of the Rutter behavioral questionnaire. These differences persisted at a 4-yr follow-up, and their school performance was consistently poorer than that of the controls.