Impact of sickle cell disease on executive functioning in an adult population

Children diagnosed with sickle cell disease (SCD) struggle with executive functions (EF); however, there is a paucity of research on neuropsychological outcomes in adults with SCD. This study aimed to examine differences in EF between adults with SCD and healthy controls. Thirty- one patients with SCD and 34 healthy controls (ages 18-45) participating in an IRB-approved Children’s Hospital Los Angeles (CHLA) study of cerebral blood flow underwent neuropsychological evaluation using the Delis–Kaplan Executive Function System (D-KEFS) Trail Making and Color Word Interference Tests and the Wechsler Adult Intelligence Scale - Fourth Edition (WAIS-IV) Digit Span subtest to assess various aspects of EF. The Wechsler Abbreviated Scale of Intelligence - Second Edition (WASI-II) was administered to estimate general intellectual ability. There were no significant differences between groups related to age, gender, race, parental education, or general intellectual ability; however, the control group was estimated to have significantly higher current combined annual family income as compared to patients with SCD, x2 (6, N = 65) = 10.87, p = .02. Therefore, income was statistically controlled for during analyses. Both groups performed in the solidly average range across EF measures and no significant differences were noted between groups in working memory, F(1) = .009, p = .93, ηp2 = .000; inhibition, F(1) = .156, p = .03, ηp2 = .03; or cognitive flexibility, F(1) = 3.11, p = .08, ηp2 = .06. Adults with SCD in this study performed comparably to healthy controls. Early treatment with hydroxyurea to the maximum tolerated dose may improve prognosis and serve as a protective factor against EF deficits in adults with SCD. However, additional research is needed to better understand how treatment protocols influence neuropsychological outcomes in this population