Neuropsychological Profile of Children in Relation to Dentine Lead Level and Socioeconomic Group

Abstract

The adverse effects of lead intoxication on neuropsychological development were first systematically studied by Byers and Lord (1943) in their follow-up of 20 children who had been hospitalized previously because of lead intoxication. They reported that 19 of the children later made unsatisfactory progress in school, presumably due to sensorimotor deficits, short attention span, and behavioural disorders. Since that time, many studies have assessed cognitive and behavioural variables in children with varying degrees of low- level lead exposure. Some studies have reported general intellectual or specific cognitive impairment among affected children (de la Burde and Choate, 1972, 1975; Perino and Ernhart, 1974; Landrigan et al, 1975; Needleman et al, 1979; Thatcher et al, 1983; Winneker et al, 1982a, b; Yule et al, 1981; Shapiro and Marecek, 1984), while others have failed to replicate these findings (Kotok et al, 1977; Lansdown et al, 1974; McNeil et al, 1975; Ernhart et al, 1981 and Smith et al, 1983). Rutter (1980) pointed out that the interpretation of a number of these studies is obscured by methodological limitations, including inadequate markers of exposure to lead, insensitive measures of performance, bias in selection of subjects and inadequate handling of confounding covariates.