Neurocognitive functioning in preschool children with sickle cell disease

BACKGROUND: Children with sickle cell disease (SCD) experience neurodevelopmental delays; however, there is limited research with preschool age children. This study examined neurocognitive risk and protective factors in preschoolers with SCD. PROCEDURE: Sixty-two patients with SCD (60% HbSS/HbSβ(0)-thalassemia; 40% HbSC/HbSβ(+)-thalassemia) between the ages of 3 and 6 years (Mean=4.77 years) received a neuropsychological evaluation as routine systematic surveillance. Patients were not selected for disease severity, prior central nervous system findings, or existing cognitive concerns. Thirty-four patients (82% HbSS/HbSβ(0)-thalassemia) were prescribed hydroxyurea (HU) at the time of their neuropsychological evaluation. On average, these patients had been prescribed HU at 2.15 (Standard Deviation=1.45) years of age. The average dose was 28.8 mg/kg/day. Besides genotype, there were no group differences in medical or demographic factors based on HU treatment status. RESULTS: Patients with HbSS/HbSβ(0)-thalassemia scored below normative expectations on measures of intelligence, verbal comprehension, and school readiness (false discovery rate adjusted p-value [pFDR]0.05). Greater social vulnerability at the community level was associated with poorer performance on measures of intellectual functioning, verbal comprehension, visuomotor control, and school readiness, as well as parent report of executive dysfunction (pFDR