McCarthy Scales

Bonithon-Kopp et al. (1986b) investigated another potential marker for lead exposure. Maternal and infant hair lead levels, determined from hair samples taken at birth, were found to be correlated inversely with results on neurobehavioral tests (McCarthy Scales of Children s Abilities) when the children were tested at 6 years of age. Other studies have also reported associations between hair lead levels and behavioral or cognitive test scores, but measures of lead in hair may not accurately reflect internal body burden of lead, and such data should not be used to evaluate internal dose-response relationships (EPA 1986a). 

What are these subclinical effects Very simply, they are effects that occur at blood lead levels below those that produce clinically measurable effects - they occur in the absence of any sign of overt lead poisoning. These effects can be detected only by studying various forms of behavior, such as degree of hyperactivity and classroom attention span, and performance on various tests of intelligence and mental development. Deficits in neurobehavioral development, as measured by two widely used tests - the Bayley and McCarthy Scales - have been reported in children exposed prenatally (via maternal blood) to blood... 

Administration of 5 of 18 possible neuropsychological development tests from the McCarthy Scales of Children s Abilities to 19 of these exposed children at 2..S 4 years of age showed a statistically... 

General Cognitive Index (GCI) of the McCarthy Scales of Children s Abilities (to estimate cognitive ability) ... 

McCarthy Scales of Children s Abilities, (2) the Preschool Language Scale, (3) the Woodcock-Johnson Tests of Achievement - Letter and Word Recognition, (4) Woodcock-Johnson Tests of Achievement -Applied Problems and, (5) the Bender Gestalt test, and (6) the Child Behavior Checklist. The test results were similar to what would be expected from a healthy, well-developing U.S. population. No test indicated a deleterious effect of methylmercury from the exposure levels received in this population. 

Newborn children from mothers who ate oontaminated fish were more likely to exhibit hypoactive reflexes, more motor immaturity, poorer lability of states, and greater amount of startle. Testing at 4 years of age found that prenatal exposure was associated with poorer performance on the Verbal and the Memory scales of the McCarthy Scales of Children s Abilities, as well as less efficient visual discrimination processing and more errors in short-term memory scanning. Evaluation of the children at 11 years of age showed that prenatal exposure was significantly associated with lower full-scale and verbal IQ scores and poorer reading word comprehension. 

Although differences in end points assessed and age of assessment might explain the failure of the SCDS to detect the associations found in the Faroe Islands study, findings from the New Zealand study and the Seychelles pilot study suggest that the discrepancies between the Faroe Islands and the main Seychelles studies are probably not due to differences in the assessments. The New Zealand study found associations between MeHg exposure and scores on the McCarthy Scales of Children s Abilities (the primary outcome measure used in the SCDS) at about the same age of assessment as in the Seychelles study, in a study with full control for potential confounding inflnences. Associations with prenatal Hg exposnre were even seen on the McCarthy scales and the PLS in the 217-member Seychelles pilot study at 5.5 years of age, albeit with only limited control for socioenvironmental inflnences. 

Note MSCA McCarthy scales of children s abilities. GCI, general cognitive index. UIE urinary iodine excretion at 12 weeks of gestation. TSH, thyrotropin. Bold typed numbers paired p < 0.05 for the difference between subgroups, a pg/l b mU/l. 

Nearly all tests used for assessing the children s mental level had, at an earlier stage, been adapted to the Spanish population that was the case with, for example, the Bayley Scales of Infant Development, the McCarthy Scales of Children s Abilities, and Cattell s Culture Fair Intelligence Test. Some of the psychomotor tests that were not adapted to Spain were included in the survey anyway because of their expected relevance. 

Inner-city children from New York City (50) Exposure PbB 40-70 rg/dl Significantly lower performance in various McCarthy Scales Perino and Ernhart (1974)... 

Port Pirie, Australia, children (537) exposed from a Pb smelter McCarthy Scales (MSCA), 4 years old Integrated and year-specific PbB means by quartile Integrated PbB most strongly inversely associated with GCI scores McMichael etal. (1988)... 

Children in the McCarthy At 4 years, PbB McCarthy Scales Wasserman... 

Mexico City cohort (112) McCarthy Scales GCl, 54 Geometric mean, 24-36 GCl adjusted score at 48 Schnaas et al. r"... 

A subset of the cohort (N = 332) was tested at 4 years of age using the McCarthy Scales. By this age, the smelter group mean PbB had risen to 40 pg/dl (rounding) versus controls mean of 10 pg/dl (rounding). GCI scores were statistically inversely associated with all postnatal exposure markers and with prenatal values > 20 pg/dl (Wasserman et al., 1994). At 7 years of age, children (A = 301) were tested using the Third Edition, Wechsler (WlSC-III) IQ scales and various exposure markers (Factor-Litvak et al., 1999). Adjusted for confoimders, there was a statistically significant inverse association of Performance IQ on the WISC-III tests with an integrated exposure measure, the lifetime Area-Under-the-Curve measurements, at 5—7 years. 

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