Furthermore, although global measures of intellectual functioning have proven to be sensitive measures of exposure to a number of environmental chemicals, this has not been the case for prenatal exposure to alcohol or drugs (NIDA 2000).
Numerous studies of children have shown that lead exposure reduces overall cognitive functioning in children, both cross-sectionally and longitudinally, but most such studies examine omnibus measures of intellectual functioning rather than domain-specific effects [ 35, 42– 42].
All patients and control subjects underwent standardized cognitive assessments including measures of intellectual functioning, IQ (Nelson and O'Connell, 1978; Wechsler, 1997) and measures of verbal learning and design learning (Coughlan et al., 2007) previously demonstrated to be sensitive to the integrity of temporal structures (Baxendale et al., 2006) (Table 1).
Analyses first estimated differences in the three measures of intellectual function, based only on the sociodemographic maternal factors, using linear regression models.
Exposure to As from drinking water is associated with reduced scores on measures of intellectual function, before and after adjusting for water Mn, for BPb, and for socio-demographic features known to contribute to intellectual function.
Exposure to As from drinking water was associated with reduced scores on measures of intellectual function, before and after adjusting for sociodemographic features known to contribute to intellectual function.
The earlier measures of intellectual function in the Rochester children (i.e., at 3 and 5 years of age) were measured using the Stanford Binet test (Canfield et al. 2003).
Also, the standard deviations for the various measures of intellectual function show very similar standard deviations in our samples at 6 and 10 years of age, so that it does not appear that there is substantially more measurement "noise" in the younger sample.
After adjustment for core variables, the associations between urinary As and measures of intellectual function were not statistically significant for Full-Scale (B = −1.78, p = 0.21), Performance (B = −0.81, p = 0.17), Verbal (B = −0.16, p = 0.81), or Processing Speed raw scores (B = −0.93, p = 0.18), but were in the anticipated direction.
After adjustment for core variables, the associations between urinary As and measures of intellectual function were not statistically significant for Full-Scale (B = −2.9, p = 0.09), Performance (B = −2.2, p = 0.14), or Verbal scores (B = −0.7, p = 0.11) but were in the anticipated direction.
The Wechsler Abbreviated Scale of Intelligence is a reliable and valid measure of intellectual functioning in children and adults.
