Cognitive functioning and brain magnetic resonance imaging in children with sickle cell disease

Objective. Brain magnetic resonance imaging (MRI) and neuropsychological evaluations were conducted to determine whether neuroradiographic evidence of infarct in children with sickle cell disease between ages 6 and 12 years would result in impairment in cognitive and academic functioning. Method and Design. Children enrolled in the Cooperative Study of Sickle Cell Disease were evaluated with brain MRI and neuropsychological evaluation. Completed studies were obtained for 194 children, 135 with HbSS. MRIs were categorized according to the presence of T2-weighted, high-intensity images suggestive of infarct and were further categorized on the basis of a clinical history of cerebrovascular accident (CVA). An abnormal MRI but no clinical history of CVA was classified as a silent infarct. Neuropsychological evaluations included assessment of both global intellectual functioning and specific academic and neuropsychological functions. Results. Central nervous system (CNS) abnormalities were identified on MRI in 17.9% of the children (22.2% of children homozygous for HbS), and a clinical history of CVA (N = 9, 4.6%) was identified in only children with HbSS disease. Subsequent analyses examined only children with HbSS. Children with a history of CVA performed significantly poorer than children with silent infarcts or no MRI abnormality on most neuropsychological evaluation measures. Children with silent infarcts on MRI performed significantly poorer than children with no MRI abnormality on tests of arithmetic, vocabulary, and visual motor speed and coordination. Conclusions. These results substantiate the importance of careful evaluation, educational planning, and medical intervention for CNS-related complications in children with sickle cell disease.