Verbal working memory in children with congenital hypothyroidism

Working memory is a cognitive system comprised of both short-term memory and controlled attention components. Because the working memory system is critical in many other cognitive abilities, academic success in childhood is dependent on adequate working memory functioning. Indeed children with attention deficit hyperactivity disorder (ADHD), who demonstrate working memory deficits, are at high risk for underachievement. In ADHD, the working memory deficit is believed to reflect primarily a deficit in controlled attention. However, working memory deficits can also arise from deficits in short-term memory. Research has suggested that children with congenital hypothyroidism (CH) have short-term memory difficulties. Furthermore, like children with ADHD, children with CH are at risk for underachievement. Therefore, it was hypothesized that children with CH would also show working memory difficulties reflecting problems with short-term memory.;Children with CH, children with ADHD, and a group of typically developing children were compared on two computerized working memory tasks, the n-Back task and the Item Recognition task. Both tasks were developed to manipulate the short-term memory and controlled attention demands of working memory. No Group effects or interactions were found on the n-Back task. However, on the Item Recognition task, the ADHD group was outperformed by the Control group, although this difference was not specifically driven by the controlled attention component. Furthermore, although the CH group did not differ from either the ADHD or the Control group overall, females with CH did show a greater decrement in performance with increasing short-term memory load compared to females in the control group. These results indicate that although children with CH may not have working memory deficits per se, females with CH may have difficulty with the short-term memory component of working memory. Functional independence of the short-term memory and controlled attention components of working memory was not observed, but the findings provide some direction for further research regarding this issue.