The impact of early childhood lead exposure on brain organization: a functional magnetic resonance imaging study of language function

OBJECTIVES. The purpose of this work was to assess the long-term impact of childhood lead exposure on the neurosubstrate of language function and brain organization. METHODS. Young adults from the Cincinnati Lead Study were recruited to undergo functional magnetic resonance image scanning while performing a verb generation task. These subjects have been followed from birth through early childhood with extensive documentation of lead exposure, neuropsychology, and behavior. Forty-two subjects provided useful imaging data. The locale, strength, and the correlation between brain language activation and childhood blood lead concentration were studied. RESULTS. After adjusting for potential confounders, the activation in left frontal cortex, adjacent to Broca's area, and left middle temporal gyrus, including Wernicke's area, were found to be significantly associated with diminished activation in subjects with higher mean childhood blood lead levels, whereas the compensatory activation in the right hemisphere homolog of Wernicke's area was enhanced in subjects with higher blood lead levels. CONCLUSION. This study indicates that childhood lead exposure has a significant and persistent impact on brain reorganization associated with language function. www.pediatrics.org/cgi/doi/10.1542/ peds.2006-0467 doi:10.1542/peds.2006-0467 Key Words environmental pollutants, lead poisoning, neuroimaging, language development, pediatric research Abbreviations fMRI--functional magnetic resonance imaging CLS--Cincinnati Lead Study EPI--echo planar imaging BOLD--blood oxygen level dependant SES--socioeconomic status IQ--intelligence quotient ROI--region of interest
CHILDHOOD LEAD EXPOSURE is inversely associated with intellectual abilities, academic achievement, and psychomotor development. (1-4) Even low-level lead exposure can negatively impact a wide range of cognitive functions, such as [...]