Psychoeducational outcome in children with early-treated congenital hypothyroidism

Objectives. To describe the psychoeducational characteristics of children with congenital hypothyroidism (CH) identified through newborn screening and to study changes over time. Method. Examined were 83 children with early-treated CH, who were long-time participants in a prospective study of outcome after newborn screening, and 120 control children who were classmates (n = 80) or siblings (n = 42). Children were tested during the third (53 children with CH and 46 control children) or the sixth (51 children with CH and 76 control children) grades at school with 21 children with CH being seen in both grades. Test instruments included multiple measures of achievement and cognitive abilities as well as behavior rating scales completed by parents and teachers. Results. CH was associated with a slightly increased risk of learning disabilities in grade 3 but not grade 6. Third grade CH children scored lower than control children on tests of reading comprehension and arithmetic but did not differ on word recognition, writing, or spelling. Sixth grade CH children performed similar to controls on basic achievement tests but were reported to be doing poorer in several subject areas. For children with CH in grade 3, delayed skeletal maturity at diagnosis was associated with poorer word recognition ability and a longer period for normalizing thyroid hormone in infancy was correlated with weaker skill in learning sound-symbol correspondences. Conclusion. Early-treated CH is associated with mild delays in several basic achievement areas (reading comprehension and arithmetic) at the third grade level, with catch up by the sixth grade. However, as other findings indicate cognitive problems do persist into adolescence in memory, attention, and visuospatial processing areas, the implications of these deficits for other educational accomplishments needs additional follow-up.