Neurocognitive Functions in Children and Adolescents with Subclinical Hypothyroidism

OBJECTIVE Hypothyroidism is a metabolic condition that can lead to cognitive and behavioral deficits in children and adolescents. However, there is less evidence about subclinical hypothyroidism (SH) as a risk factor for neuropsychological disorders in childhood. The aim of this study was to evaluate cognitive functions like active/passive attention, maintaining attention, and response inhibition in pediatric patients with SH. METHODS Seventeen patients (between 7-17 years old) with SH were tested with the Stroop test, Verbal Fluency test and the sub-tests of the Wechsler intelligence scale for children-Revised (WISC-R). SH diagnosis was based on the mild increase of serum thyrotropin (TSH) level together with a normal serum free thyroxine level and an exaggerated TSH response to thyrotropin-releasing hormone. RESULTS Out of seventeen cases, 10 (59%) were girls and 7 (41%) were boys. Six cases were obese and 5 were overweight. The children in the SH group, as compared to the control group, obtained significantly lower scores on both the Digit Span subtest of the WISC-R and the Stroop subtests, which are sensitive to attention. No significant differences were found between the SH group and the healthy controls in verbal fluency and encoding tests. CONCLUSION In this study, pediatric patients with SH showed poor performance in tests measuring attention. Therefore, we want to stress the importance of close collaboration between pediatric endocrinology and child and adolescent psychiatry departments.