Cognitive/Academic/Executive Functioning and Medical Variables
There were no statistically significant differences found between more
severe subtypes (Hemoglobin SS or Hemoglobin Beta 0) and less severe
types of SCD (Hemoglobin SC or Hemoglobin Beta +) in terms of mean
cognitive score, mean academic score, or parent-reported global
executive functioning. Mean cognitive scores, cognitive subtest
variance, cognitive subtest range, and mean academic scores were not
related to overall hemoglobin, sickle hemoglobin, or fetal hemoglobin
levels that were taken +/- 45 days of testing, nor were mean cognitive
or academic score related to TCD right or left MCA velocities; though of
note, all study participants with a TCD (n = 40) had results in the
normal range. Patients with mean academic scores 1 SD below the
mean demonstrated marginally significant differences in left MCA
velocity (t (37) = -1.82, p = .076). There was a
significant, positive association between mean corpuscular volume (MCV)
and mean cognitive score (r = .29, p = .03), but not between MCV
and academic performance; however, patients with mean academic scores 1
SD or below the mean had lower mean MCV (t(53) = 2.66, p = .01).
None of the medical variables assessed demonstrated positive
associations with auditory attention scaled scores on the NEPSY-II.
Similarly, neither hemoglobin nor MCV were significantly correlated with
emotional, cognitive, or behavioral regulation T-scores on the BRIEF-2
or with inattention or hyperactivity T-scores on the Conners-3. Of note,
there was a significant correlation found between MCV and both parent (r
= .28, p = .05) and self-reported (r = .45, p = .001)
psychosocial health summary, but not the physical health summary, on the
PedsQL. Neither cognitive nor academic functioning were correlated with
parent or child reports of pain on the PedsQL.