Individuals with sickle cell disease (SCD) are at increased risk for developing impairment across cognitive domains, although the most common deficits are thought to be related to processing speed and executive functions. One of the most common ways of evaluating cognitive functioning is through the administration of intellectual tests. While lower overall intellectual functioning in individuals with SCD compared to healthy controls has been found, the specific pattern of strengths and weaknesses across indices is not well known. Anecdotally, it has been observed at our clinic that individuals with SCD are more likely to show relative or significant weaknesses in visuospatial abilities, but this has not been formally investigated. Further, based on the extant research, individuals with SCD would likely demonstrate lower working memory and processing speed indices, but, as far as we are aware, this has not been investigated either. The purpose of the present study is to examine the intellectual profiles, including areas of relative and significant strengths and weaknesses, of children and adolescents with SCD.

Participants are children and adolescents (age 6-16) with SCD who were referred for a neuropsychological evaluation at Montefiore Medical Center’s Neuropsychological Assessment Service from 2015 to 2022. These participants (N=54) were identified through a thorough review of patients seen through this service and were administered the Wechsler Intelligence Scale for Children, Fifth Edition (WISC-V; Wechsler, 2014). Mean scores were calculated for WISC-V indices. In addition, differences were calculated between WISC-V indices (e.g., VCI-VSI, etc.), and a discrepancy analysis was conducted comparing the base rates of these differences in the present sample to the WISC-V standardization sample.

In our sample, the mean total FSIQ of our sample was 85 (SD=14.5). The following mean scores were obtained across indices: VCI, SS=90 (SD=14.5); VSI, SS=86.5 (SD=14.9); FRI, SS=90 (15.5); WMI, SS=89 (SD=15.6); and PSI, SS=82 (SD=17.4). Many of the index score discrepancy base rates were similar to the standardization sample. However, our sample had greater discrepancies between several indices compared to the standardization sample. In particular, the following base rate discrepancies between index scores emerged as being different in our sample compared to the standardization sample: VCI>VSI and VCI>PSI. Notably, a 30+ point difference VCI>VSI was found in 6% of our sample (compared to 1.6% of the standardization sample) and a 30+ point difference between VCI>PSI was found in 12% of our sample (compared to 4.6% of the standardization sample). In addition, a 10+ point difference found between VCI>PSI was found in 50% of our sample (compared to 29% of standardization sample).

In our sample, FSIQ and index scores fell approximately 0.5-1.33 SD below the standardization sample means, with the lowest index scores being PSI and VSI. Consistent with the literature, the PSI (but not WMI) emerged as an area most discrepant to other indices (particularly VCI). In line with our observations, the VSI emerged as an area of relative difficulty as compared to the VCI. These results suggest that, in addition to processing speed, visuospatial/constructional ability is an area that warrants consideration in the assessment of individuals with SCD.