Intellectual impairment and TCD evaluation in children with sickle cell disease and silent stroke

Background

Sickle cell disease (SCD) may impair intellectual activity; 25% of SCD patients have a significant cognitive deficit. Our aim was to verify in a cohort of children with HbSS if the presence of silent strokes or altered Time Averaged Mean velocities of Maximum blood flow (TAMM) detected by Transcranial Color Doppler (TCD) Sonography are indicators of impaired intellectual ability.

Methods

Thirty-five consecutive SCD patients (17 males; mean age: 8.6 ± 3.22) were subdivided into two groups according to neuro-psycological deficits. Cognitive function was assessed by WISC III (for the children aged 6–16 years) and WPPSI (for the children aged 4–6 years). All patients underwent a TCD scan of the main intracranial arteries, in order to detect any increase of TAMM velocities (normal <170 cm/s; altered >170 cm/s) and a cerebral MRI to reveal any silent stokes.

Results

According to the neuro-psycological evaluation, 29/35 (82.8%) patients (Group 1) had a “normal” Total Intelligence Quotient (TIQ ≥70), while 6/35 (17.2%) patients (Group 2) were defined intellectually impaired (TIQ <69).

TCD detected altered velocities in 8/35 (22.8%) patients. No significant differences were found in the percentage of altered TAMM velocities between the two groups (Fisher's exact test: p = 0.42).

MRI detected silent ischemic lesions in 14/35 patients (40.0%). No significant differences were found in silent stroke frequencies (Fisher's exact test: p = 0.25) between Group 1 and Group 2.

Conclusion

With the limitations of the study sample, according to our results, altered TAMM values and silent strokes do not seem to be indicators of impaired intellectual ability in SCD patients.