Cerebral Cortical Thickness Morphometry and Neurocognitive Correlations in Adolescents With Congenital Hypothyroidism

Abstract

Background Subtle cognitive impairments have been described in children with congenital hypothyroidism (CH) detected by neonatal screening (NS), even with early and adequate treatment. Patients with CH may present brain cortical thickness (CT) abnormalities, which may be associated with neurocognitive impairments. Aims To evaluate the CT in adolescents with CH detected by the NS Program (Paraná, Brazil), and to correlate possible abnormalities with cognitive level and variables of neurocognitive prognosis. Methods Review of medical records followed by psychometric evaluation of adolescents with CH. Brain magnetic resonance imaging with analysis of 33 brain areas of each hemisphere was performed in 41 patients (29 females) and in a control group of 20 healthy adolescents. CT values were correlated with Full-scale Intelligence Quotient (FSIQ) scores, age at start of treatment, pretreatment thyroxine levels and maternal schooling. Results No significant difference in CT between patients and controls. However, there was a trend toward thinning in the right lateral orbitofrontal cortex among patients and in the right postcentral gyrus cortex among controls. CT correlated significantly with FSIQ scores and with age at start of treatment in one area, and with hypothyroidism severity in five brain areas. Maternal schooling level did not correlate with CT but was significantly correlated with FSIQ. Cognitive level was within average in 44.7% of patients (13.2% had intellectual deficiency). Conclusions There was a trend toward morphometric alterations in the cerebral cortex of adolescents with CH compared with healthy controls. The correlations between CT and variables of neurocognitive prognosis emphasize the influence of hypothyroidism on cortical development. Socioeconomic status exerts a limiting factor on cognitive outcome.