Hippocampal volume and cognitive performance in children with congenital heart disease

BACKGROUND: Congenital heart disease (CHD) is associated with an increased risk of brain abnormalities. Studies indicate a particular vulnerability of the hippocampus to hypoxia and inflammation. Yet, information regarding the hippocampus and its relation to cognitive function in school-age children with CHD remains scarce. METHODS: Children who underwent cardiopulmonary bypass surgery for CHD (N = 17) and healthy controls (N = 14) at 10 years of age underwent neurodevelopmental assessment and cerebral magnetic resonance imaging to measure IQ, working memory performance and hippocampal volume. RESULTS: IQ was significantly lower in children with CHD compared to controls (98 vs 112, P = 0.02). Children with CHD showed worse working memory performance with significantly lower scores in the letter-number sequencing test (P = 0.02). After adjusting for total brain volume, hippocampal volume was smaller in children with CHD compared to controls (P < 0.01). Smaller hippocampal volume was associated with lower IQ (P = 0.04), and digit span scaled score (P = 0.03), but not with other working memory tests (P > 0.1). CONCLUSION: This study suggests that the hippocampus may be particularly susceptible in children with CHD thereby contributing to cognitive impairments. Further research is necessary to understand the contribution of the hippocampus to cognitive impairments in children with CHD. IMPACT: IQ is significantly lower in school-age children with congenital heart disease compared to controls. Working memory performance seems to be worse in children with congenital heart disease. Smaller hippocampal volume is associated with lower IQ and seems to be associated with lower working memory performance. The study adds knowledge on the etiology of cognitive impairments in school-age children with congenital heart disease.