Attentional correlates of dentin and bone lead levels in adolescents

In an effort to determine whether specific aspects of attention are impaired by lead, the performance of 79 subjects (aged 19 and 20 y) on a neuropsychologically based battery of tests of attention was examined in relation to lead levels in deciduous teeth (dentin), current blood, and tibia and patella bones measured by K-X-ray fluorescence. Dentin lead levels averaged 14 [mu]g/g. Most bone lead levels were less than 10 [mu]g/g. Dentin lead levels were related inversely to scores on two of four attention factors: focus-execute (ability to select and respond to critical information) and shift (ability to shift focus adaptively). Few significant associations were observed between bone lead levels and performance. Five individuals with the ALA-D 1-2 isozyme phenotype tended to achieve more optimal scores. Executive and self-regulation functions may be among the cognitive skills targeted by lead.
THE MAJOR ENDPOINT examined in nearly all studies of low-level lead neurotoxicity is IQ, a familiar global index of impairment. IQ reflects largely neuropsychological product rather than process, performance rather [...]