RESIDUAL COGNITIVE DEFICITS 50 YEARS AFTER LEAD-POISONING DURING CHILDHOOD

The long term neurobehavioural consequences of childhood lead poisonin g are not known. In this study adult subjects with a documented histor y of lead poisoning before age 4 and matched controls were examined wi th an abbreviated battery of neuropsychological tests including measur es of attention, reasoning, memory, motor speed, and current mood. The subjects exposed to lead were inferior to controls on almost all of t he cognitive tasks. This pattern of widespread deficits resembles that found in children evaluated at the time of acute exposure to lead rat her than the more circumscribed pattern typically seen in adults expos ed to lead. Despite having completed as many years of schooling as con trols, the subjects exposed to lead were lower in lifetime occupationa l status. Within the exposed group, performance on the neuropsychologi cal battery and occupational status were related, consistent with the presumed impact of limitations in neuropsychological functioning on ev eryday life. The results suggest that many subjects exposed to lead su ffered acute encephalopathy in childhood which resolved into a chronic subclinical encephalopathy with associated cognitive dysfunction stil l evident in adulthood. These findings lend support to efforts to limi t exposure to lead in childhood.