[Correlation between development indices and later intelligence quotients--the follow-up study of chlorinated...

All intelligence tests are for children old than two and a half years; we still do not have an intelligence assessment tool for children younger than this age. If we knew the relationship between the intelligence quotient and developmental indices as measured by the Bayley Scale of Infant Development (BSID), it would allow us to assess the mental development of young children earlier and to start adequate management sooner. The present study was designed to meet this need. We collected our data from a six-year follow-up study of Yu-Cheng (oil disease) children born to mothers who had a history of ingesting rice cooking oil contaminated with polychlorinated biphenyls (PCBs) in 1978-1979 and their matched controls. We analyzed the correlations between the developmental indices of the BSID assessed on 44 pairs of Yu-Cheng children and their controls in 1985 and the Stanford-Binet Intelligence Quotients (S-B IQ) assessed on the same group of children in 1987 and 1988. For the matched controls, we found practically no significant correlation between the BSID developmental indices and the S-B IQ (r = .04-.20, p = .23-.82). In the Yu-Cheng children, that is at-risk group, there was a significant correlation between the Mental Developmental Index (MDI) of BSID and the S-B IQ (r = .33-.43, p = .01-.05) and between the Psychomotor Developmental Index (PDI) of BSID and the S-B IQ (r = .31-.47, p = .00-.07). We conclude that the development indices of BSID has a better predictive power on the intelligence among the at-risk group such as Yu-Cheng children.