Brain risk seen in sickle cell kids.

Brain Risk Seen in Sickle Cell Kids

A new study indicates that children with sickle cell anemia, already at risk of life-threatening infections and strokes, may also suffer significant neuropsychologic deficits. The researchers find that children inheriting the red blood cell disorder have lower IQs and more learning disabilities than do their siblings without the disease -- perhaps as a result of subtle brain damage during their first few years of life.

The study is small and awaits verification -- some of which may come from a federally funded trial now getting underway. If confirmed, the findings could radically alter the prevailing view of sickle cell pathology in children, which today generally attributes any lag in school progress to the psychological stresses and missed school days common among youngsters with the disease.

The research, described in the December PEDIATRICS, is the first published report on the topic since a 1963 study found no significant intellectual differences between sickle cell children and controls. But according to Andrea V. Swift, who led the new study, unpublished data hint that the gap between the two groups has widened during the past two decades. She notes that cognitive scores have remained stagnant in sickle cell kids as a group, while increasing in controls. Because the disease primarily strikes blacks, Swift's team suggests that improved educational opportunities for blacks in recent years may make cognitive differences in afflicted children more apparent.

Swift, then at the University of Georgia in Athens, used a palette of standard psychological tests to measure cognitive abilities in 21 children, 7 to 16 years old, with sickle cell anemia and no known history of neurologic disease. She compared their scores with those of siblings within the same age range who did not inherit the disease. The sickle cell group scored significantly lower than the control group on almost all cognitive measures, report Swift and her colleagues from the University of Georgia and the Medical College of Georgia in Augusta. For example, full-scale IQ scores measured by the Wechsler Intelligence Scale for Children averaged 94.3 in controls and 77.7 in the sickle cell group.

"These are not kids that are scoring lower because of missing class or being hospitalized a lot," says Swift, now a school psychologist in Augusta. "The two groups of children really are different in measures of intellectual ability and achievement."

The researchers remain uncertain about the cause of these deficits. But the similar degree of impairment seen throughout the age range suggests the problem occurs early in development, they say -- perhaps within the first year or two, when red blood cells begin producing the abnormal hemoglobin characteristic of the disease (SN: 12/2/89, p.360). "Maybe there is something metabolic going on that's not providing the best environment for brain development when the brain is developing very rapidly," Swift says.

The team found no significant cognitive deficits in children with sickle cell trait -- a mostly asymptomatic condition in those inheriting one abnormal and one normal hemoglobin gene. Nonetheless, says study coauthor George W. Hynd, the new findings hint that all preschoolers inheriting even one sickle cell gene should be carefully evaluated and followed over the years for signs of intellectual delay that might respond to early educational intervention.

A three-year National Institutes of Health study should clarify and refine Swift's findings, says Daniel J. Burbach, a clinical psychologist at Duke University Medical Center in Durham, N.C. The multicenter study will include brain scans capable of identifying minor structural abnormalities that may provide clues to the source of any cognitive deficits.