Behavioral and neurological effects of symptomatic and asymptomatic lead exposure in children.

Forty-five children 4 to 8 yr of age who had been exposed to environmental lead were studied, consisting of an acute encephalopathy group and groups with short- and long-term exposure but without encephalopathy. Control children were matched for age, sex, race, and socioeconomic status with lead-exposed subjects, but lived in post-1945 housing and had negative neurological history and blood tests. The encephalopathy group had a significantly higher incidence of neurological deficits, retarded mental development, and higher hyperactivity than control subjects. Children with short- and long-term exposure short of encephalopathy were somewhat inferior to matched control subjects, but not to a statistically significant extent.