Parent education and biologic factors influence on cognition in sickle cell anemia

"Everyone screens to some extent": Barriers and facilitators of developmental screening among children with sickle cell disease: A mixed methods study

BACKGROUND

Developmental delays are common among children with sickle cell disease (SCD). Existing guidelines support consistent screening to increase the identification of deficits and support referral to rehabilitative interventions, yet adherence remains variable. This study sought to assess current practices and identify barriers and facilitators to improve developmental screening for children 0-3 years with SCD.

PROCEDURE

A mixed methods approach, guided by the Exploration and Preparation stages of the Exploration, Preparation, Implementation, and Sustainment (EPIS) framework, assessed developmental screening practices among primary care providers and hematologists. Phase 1 included the SCD Developmental Surveillance and Screening Guideline and Practice Survey. Phase 2 included the SCD Developmental Screening Organizational Survey alongside semi-structured interviews. Descriptive and qualitative methods summarized the findings.

RESULTS

Thirty-three providers from general pediatrics and hematology completed phase 1. Use of standardized developmental screening measures was variable, with the most frequently used being the Modified Checklist for Autism in Toddlers (77%) and the Ages and Stages Questionnaire (55%). Fifteen providers participated in phase 2, and reported they were most likely to engage in changes to improve their practice (mean = 4.4/5) and least likely to support spiritual health and well-being (mean = 3.5/5). Three themes emerged:(i) developmental screening is not standardized or specific to SCD, (ii) children with SCD benefit from a multidisciplinary team, and (iii) healthcare system limitations are a barrier.

CONCLUSIONS

Developmental screening is inconsistent and insufficient for young children with SCD. Providers are interested in supporting children with SCD, but report a lack of standardized measures and consistent guidance as barriers.

Distribution of Silent Cerebral Infarcts in Adults With Sickle Cell Disease

BACKGROUND AND OBJECTIVES

Previously we demonstrated that 90% of infarcts in children with sickle cell anemia occur in the border zone regions of cerebral blood flow (CBF). We tested the hypothesis that adults with sickle cell disease (SCD) have silent cerebral infarcts (SCIs) in the border zone regions, with a secondary hypothesis that older age and traditional stroke risk factors would be associated with infarct occurrence in regions outside the border zones.

METHODS

Adults with SCD 18-50 years of age were enrolled in a cross-sectional study at 2 centers and completed a 3T brain MRI. Participants with a history of overt stroke were excluded. Infarct masks were manually delineated on T2-fluid-attenuated inversion-recovery MRI and registered to the Montreal Neurological Institute 152 brain atlas to generate an infarct heatmap. Border zone regions between anterior, middle, and posterior cerebral arteries (ACA, MCA, and PCA) were quantified using the Digital 3D Brain MRI Arterial Territories Atlas, and logistic regression was applied to identify relationships between infarct distribution, demographics, and stroke risk factors.

RESULTS

Of 113 participants with SCD (median age 26.1 years, interquartile range [IQR] 21.6-31.4 years, 51% male), 56 (49.6%) had SCIs. Participants had a median of 5.5 infarcts (IQR 3.2-13.8). Analysis of infarct distribution showed that 350 of 644 infarcts (54.3%) were in 4 border zones of CBF and 294 (45.6%) were in non-border zone territories. More than 90% of infarcts were in 3 regions: the non-border zone ACA and MCA territories and the ACA-MCA border zone. Logistic regression showed that older participants have an increased chance of infarcts in the MCA territory (odds ratio [OR] 1.08; 95% CI 1.03-1.13; p = 0.001) and a decreased chance of infarcts in the ACA-MCA border zone (OR 0.94; 95% CI 0.90-0.97; p < 0.001). The presence of at least 1 stroke risk factor did not predict SCI location in any model.

DISCUSSION

When compared with children with SCD, in adults with SCD, older age is associated with expanded zones of tissue infarction that stretch beyond the traditional border zones of CBF, with more than 45% of infarcts in non-border zone regions.

Empirically derived profiles of neurocognitive functioning in youth and young adults with sickle cell disease

OBJECTIVE

Sickle cell disease (SCD) is an inherited blood disorder associated with neurocognitive deficits. In contrast to variable-centered approaches, no known research has utilized person-centered strategies to identify multidimensional patterns of neurocognitive functioning of an individual with SCD. The purpose of the present study was to create empirically derived profiles and identify predictors of neurocognitive functioning subgroups among youth and young adults with SCD.

METHODS

Individuals with SCD (N = 393, mean age 14.05 years, age range 8-24, 50.4% female/49.6% male) completed neurocognitive assessments. Latent profile analysis derived subgroups/classes of neurocognitive functioning and determined relations with demographic and medical variables.

RESULTS

Three latent classes emerged: average functioning (n = 102, 27%), low average functioning (n = 225, 60%), and exceptionally low functioning (n = 46, 12%). Older age was associated with membership in the low average and exceptionally low functioning groups (relative to the average group). Being prescribed hydroxyurea was associated with membership in the average functioning group (relative to the low average group) and absence of hydroxyurea use was associated with membership in the exceptionally low group (relative to the low average group). Lower social vulnerability was associated with membership in the average functioning group compared to the low average and exceptionally low groups.

CONCLUSIONS

Clinicians can help reduce disparities in cognitive development for individuals with SCD by promoting early treatment with hydroxyurea and implementing methods to reduce social vulnerabilities that can interfere with access to evidence-based care.

Montreal cognitive assessment in Brazilian adults with sickle cell disease: The burdens of poor sociocultural background

Sickle cell disease (SCD) patients are at higher risk of developing silent cerebral infarcts and overt stroke, which may reflect cognitive impairment, functional limitations, and worse quality of life. The cognitive function of Brazilian adult SCD patients (n = 124; 19-70 years; 56 men; 79 SS, 28 SC, 10 S/β0, 7 S/β+) was screened through Montreal Cognitive Assessment (MoCA) and correlated the results with possible predictive factors for test performance, including sociocultural, clinical, laboratory data and brain imaging. The Median MoCA score was 23 (8-30); 70% had a 25-or-less score, suggesting some level of cognitive impairment. There were no significant associations between MoCA results and any clinical or laboratory data in SS and SC patients; however, a significant correlation (P = 0.03) with stroke was found in HbS/β-thalassemic patients. Correlations were further detected according to sociodemographic conditions, such as age (r = -0.316; P < 0.001), age at first job (r = 0.221; P = 0.018), personal (r = 0.23; P = 0.012) and per capita familiar incomes (r = 0.303; P = 0.001), personal (r = 0.61; P = 0), maternal (r = 0.536; P = 0), and paternal educational status (r = 0.441; P = 0). We further sought independent predictors of performance using multivariable regressions and increased education was an independent predictor of better scores in MoCA (0.8099, 95% confidence interval [CI]: 0.509-1.111). Brain imaging analysis showed significant and progressive atrophy in important cerebral areas related to memory, learning, and executive function. These data point to the high prevalence and impact of cognitive decline in adult SCD patients, mirrored in brain atrophic areas. It is also possible to observe the influence of sociodemographic conditions on patients' cognitive performances and the need for creating focused therapeutic plans that address these deficiencies. Moreover, the absence of a significant correlation of MoCA values with stroke in the SS and SC groups may be related to the worst sociocultural and economic conditions of the Brazilian African descent population, in which the impact of low educational stimulation on cognitive function can outweigh even the anatomical damage caused by the disease.

Neurocognitive Impairment in Ugandan Children with Sickle Cell Anemia Compared to Sibling Controls: A cross-sectional study

Introduction

Neurocognitive function in Ugandan children aged 1-12 years with sickle cell anemia (SCA) were compared to their non-SCA siblings to identify risk factors for disease-associated impairment.

Methods

This cross-sectional neurocognitive function study of children with SCA (N=242) and non-SCA siblings (N=127) used age- and linguistically-appropriate standardized tests of cognition, executive function and attention for children ages 1-4 and 5-12 years. Test scores were converted to locally derived age-normalized z-scores. The SCA group underwent standardized stroke examination for prior stroke and transcranial doppler ultrasound (TCD) to determine stroke risk by arterial flow velocity.

Results

The SCA group was younger than siblings (mean ages 5.46±3.0 versus 7.11±3.51 years, respectively; p <.001), with lower hemoglobin concentration (7.32±1.02 vs. 12.06±1.42, p <.001). Overall cognitive SCA z-scores were lower: -0.73 ±0.98 vs. siblings -0.25 ±1.12 (p<.001), with comparable findings for executive function of -1.09±0.94 versus -0.84±1.26 (p=0.045), respectively. Attention z-scores for ages 5-12 for the SCA group and controls were similar: -0.37±1.4 vs. -0.11±0.17 (p=.09). Overall differences by SCA status were largely driven by the older age group, as z-scores in the younger sub-sample did not differ from controls. Analyses revealed the strongest predictors of poor neurocognitive outcomes among the SCA sample to be the disease, age and prior stroke (each p<.001). Impact from anemia and SCA were indistinguishable.

Discussion

Neurocognitive testing in children with SCA compared to non-SCA siblings revealed poorer SCA-associated functioning in children older than age 4. Results indicate need for trials assessing impact from disease modification for children with SCA.

Neuroinflammation underlies the development of social stress induced cognitive deficit in sickle cell disease

Cognitive deficit is a debilitating complication of SCD with multifactorial pathobiology. Here we show that neuroinflammation and dysregulation in lipidomics and transcriptomics profiles are major underlying mechanisms of social stress-induced cognitive deficit in SCD. Townes sickle cell (SS) mice and controls (AA) were exposed to social stress using the repeat social defeat (RSD) paradigm concurrently with or without treatment with minocycline. Mice were tested for cognitive deficit using novel object recognition (NOR) and fear conditioning (FC) tests. SS mice exposed to RSD without treatment had worse performance on cognitive tests compared to SS mice exposed to RSD with treatment or to AA controls, irrespective of their RSD or treatment disposition. Additionally, compared to SS mice exposed to RSD with treatment, SS mice exposed to RSD without treatment had significantly more cellular evidence of neuroinflammation coupled with a significant shift in the differentiation of neural progenitor cells towards astrogliogenesis. Additionally, brain tissue from SS mice exposed to RSD was significantly enriched for genes associated with blood-brain barrier dysfunction, neuron excitotoxicity, inflammation, and significant dysregulation in sphingolipids important to neuronal cell processes. We demonstrate in this study that neuroinflammation and lipid dysregulation are potential underlying mechanisms of social stress-related cognitive deficit in SS mice.

Prevention of neurovascular complications in children with Sickle Cell Disease in the real-world setting: What adult medicine physicians should know

Neurovascular complications represent one of the most detrimental manifestations of Sickle Cell Disease (SCD), affecting many patients since infancy. They include overt stroke, silent cerebral infarcts and neurocognitive disorders. In fact, neurodevelopment can be impaired in children resulting in cognitive dysfunction in adults with SCD. This review is meant to resume the most recent guidelines about the prevention of SCD neurovascular complications and to highlight the open challenges in their implementation. Transcranial Doppler, Magnetic Resonance Imaging/Angiography and neurocognitive test are useful screening tools. Chronic transfusion regimen, hematopoietic stem cell transplantation and neurocognitive rehabilitation find indications in the context of primary and secondary prevention of neurovascular complications of SCD. However, international guidelines are often difficult to bring into the real world due to the lack of appropriate instruments and trained personnel. Many challenges have still to be faced to guarantee the best possible neurocognitive function to each child affected by SCD.

Hydroxyurea maintains working memory function in pediatric sickle cell disease

Pediatric patients with sickle cell disease (SCD) have decreased oxygen-carrying capacity in the blood and reduced or restricted cerebral blood flow resulting in neurocognitive deficits and cerebral infarcts. The standard treatment for children with SCD is hydroxyurea; however, the treatment-related neurocognitive effects are unclear. A key area of impairment in SCD is working memory, which is implicated in other cognitive and academic skills. N-back tasks are commonly used to investigate neural correlates of working memory. We analyzed functional magnetic resonance imaging (fMRI) of patients with SCD while they performed n-back tasks by assessing the blood-oxygenation level-dependent (BOLD) signals during working memory processing. Twenty hydroxyurea-treated and 11 control pediatric patients with SCD (7-18 years old) performed 0-, 1-, and 2-back tasks at 2 time points, once before hydroxyurea treatment (baseline) and ∼1 year after treatment (follow-up). Neurocognitive measures (e.g., verbal comprehension, processing speed, full-scale intelligence quotient, etc.) were assessed at both time points. Although no significant changes in behavior performance of n-back tasks and neurocognitive measures were observed in the treated group, we observed a treatment-by-time interaction in the right cuneus and angular gyrus for the 2-> 0-back contrast. Through searchlight-pattern classifications in the treated and control groups to identify changes in brain activation between time points during the 2-back task, we found more brain areas, especially the posterior region, with changes in the pattern and magnitude of BOLD signals in the control group compared to the treated group. In the control group, increases in 2-back BOLD signals were observed in the right crus I cerebellum, right inferior parietal lobe, right inferior temporal lobe, right angular gyrus, left cuneus and left middle frontal gyrus at 1-year follow-up. Moreover, BOLD signals elevated as the working memory load increased from 0- to 1-back but did not increase further from 1- to 2-back in the right inferior temporal lobe, right angular gyrus, and right superior frontal gyrus. These observations may result from increased cognitive effort during working memory processing with no hydroxyurea treatment. In contrast, we found fewer changes in the pattern and magnitude of BOLD signals across time points in the treated group. Furthermore, BOLD signals in the left crus I cerebellum, right angular gyrus, left cuneus and right superior frontal gyrus of the treated group increased continuously with increasing working memory load from 0- to 2-back, potentially related to a broader dynamic range in response to task difficulty and cognitive effort. Collectively, these findings suggest that hydroxyurea treatment helped maintain working memory function in SCD.

Catechol-O-methyltransferase gene (COMT) is associated with neurocognitive functioning in patients with sickle cell disease

PURPOSE

Neurocognitive impairment is a common and debilitating complication of sickle cell disease (SCD) resulting from a combination of biological and environmental factors. The catechol-O-methyltransferase (COMT) gene modulates levels of dopamine availability in the prefrontal cortex. COMT has repeatedly been implicated in the perception of pain stimuli and frequency of pain crises in patients with SCD and is known to be associated with neurocognitive functioning in the general population. The current study aimed to examine the associations of genetic variants in COMT and neurocognitive functioning in patients with SCD.

PATIENTS AND METHODS

The Sickle Cell Clinical Research and Intervention Program (SCCRIP) longitudinal cohort was used as a discovery cohort (n = 166). The genotypes for 5 SNPs (rs6269, rs4633, rs4818, rs4680, and rs165599) in COMT were extracted from whole genome sequencing data and analyzed using a dominant model. A polygenic score for COMT (PGSCOMT) integrating these 5 SNPs was analyzed as a continuous variable. The Cooperative Study of Sickle Cell Disease (CSSCD, n = 156) and the Silent Cerebral Infarction Transfusion (SIT, n = 114) Trial were used as 2 independent replication cohorts. Due to previously reported sex differences, all analyses were conducted separately in males and females. The Benjamini and Hochberg approach was used to calculate false discovery rate adjusted p-value (q-value).

RESULTS

In SCCRIP, 1 out of 5 SNPs (rs165599) was associated with IQ at q<0.05 in males but not females, and 2 other SNPs (rs4633 and rs4680) were marginally associated with sustained attention at p<0.05 in males only but did not maintain at q<0.05. PGSCOMT was negatively associated with IQ and sustained attention at p<0.05 in males only. Using 3 cohorts' data, 4 out of 5 SNPs (rs6269, rs4633, rs4680, rs165599) were associated with IQ (minimum q-value = 0.0036) at q<0.05 among male participants but not female participants. The PGSCOMT was negatively associated with IQ performance among males but not females across all cohorts.

CONCLUSION

Select COMT SNPs are associated with neurocognitive abilities in males with SCD. By identifying genetic predictors of neurocognitive performance in SCD, it may be possible to risk-stratify patients from a young age to guide implementation of early interventions.

Education Liaison improves implementation of school accommodations for students with sickle cell disease

BACKGROUND

Children with sickle cell disease (SCD) have lower academic attainment than healthy peers. Many benefit from neuropsychological testing (NPT) and educational accommodations, including Individualized Education Programs (IEPs) and Section 504 plans (504s). Despite medical barriers to academic attainment, many children with SCD do not receive indicated NPT or accommodations.

OBJECTIVE

We hypothesize that a dedicated Education Liaison (EL) embedded in the SCD team increases implementation of NPT and accommodations.

STUDY DESIGN

This retrospective study included children aged 5-20 years with SCD receiving care at a single center from 2017 through 2020. Univariate analysis and multiple logistic regression were performed.

RESULTS

Total 316 children with SCD were included. At baseline, 52.8% had accommodations (IEP: 24.4%, 504: 38.0%). The EL interacted with 62.0% of children. Children with EL contact were more likely to undergo NPT (odds ratio [OR]: 5.385), have an IEP (OR: 4.580), and have a 504 (OR: 2.038) (p < .001 for all). At the end of the study period, 64.6% had accommodations (IEP: 33.5%, 504: 54.4%), which increased from baseline (p < .001 for all). EL interaction was associated with overt or silent stroke history (OR: 1.911), acute chest syndrome history (OR: 2.257), hospitalizations since age 5 (OR: 3.216), and hospitalization for vaso-occlusive pain since age 5 (OR: 2.226) (p < .001 for all).

CONCLUSION

EL interaction improves access to NPT and educational accommodations among children with SCD. SCD centers should incorporate ELs in comprehensive care teams to improve access to appropriate educational accommodations.

Executive Function and Processing Speed in Children Living with Sickle Cell Anemia

Executive function and processing speed difficulties are observed in children living with sickle cell anemia (SCA). The influence of processing speed on executive function is not well understood. We recruited 59 children living with SCA and 24 matched controls aged 8-18 years between 2010 and 2016 from clinics in the UK. Children completed tests in processing speed and cognitive flexibility, subdomains of executive function. MRI scans were conducted within one year of testing; oxygen saturation was obtained on the day of testing. Hemoglobin levels were obtained from medical records. Caregivers completed the executive function questionnaire. Hierarchical linear regressions found that hemoglobin, oxygen saturation, age, infarct status, and processing speed were not independent predictors for any model. However, for all cognitive flexibility tests, there was a significant interaction between infarct status and processing speed; children without silent cerebral infarction (SCI) with faster processing speed had better cognitive flexibility. Our findings indicate that, when interpreting executive function difficulties, it is important to account for the relationship between SCI status and processing speed. More research is needed to elucidate the mechanisms, but clinically, including executive function testing as part of clinic visits by embedding psychologists within the healthcare team would appear to be a critical step.

Cognition and education benefits of increased hemoglobin and blood oxygenation in children with sickle cell disease

BACKGROUND

Among individuals with sickle cell disease (SCD), decreased hemoglobin is associated with lower oxygen saturation (SpO2) and increased risk of stroke, both of which are associated with lower intelligence quotient (IQ) scores. Thus, increasing hemoglobin and SpO2 in individuals with SCD may increase IQ and educational attainment.

METHODS

A cohort simulation model was built to determine academic performance and educational attainment based on cognitive function (measured by IQ) of a pediatric SCD cohort randomly assigned to treatment and control groups. The model contained two key stages: childhood (<10 years) and adolescence (≥10 years). In stage 1, increased hemoglobin and increased SpO2 (assigned to the treatment group) were determinants of higher IQ, prevention of IQ deterioration over time. Increased hemoglobin was also a determinant of decreased stroke risk. In stage 2, improvement in adolescent IQ as a result of treatment was a determinant of academic performance.

RESULTS

In a simulated cohort of 2000 children and adolescents with SCD (52.5% female, 50% treated), stroke incidence was predicted to be 44.4% lower among the treated group than the untreated group (4.5% versus 8.1%, respectively). The average IQ among the treated group was estimated to be 91.1 compared with 82.9 in the untreated group (a 9.9% difference; P<0.001). Finally, high school (≥12 years of education) completion rates were estimated to be 64.7% higher among the treated group: 76.1% of the treated group was projected to complete high school compared with 46.2% of the untreated group.

CONCLUSIONS

Our model predicts that an average improvement in hemoglobin of 1.1 g/dL (11 g/L) among individuals with SCD may be associated with improved neurocognition and educational outcomes. These improvements may also generate benefits not captured by our model, including improved quality of life, employment, and income.

Molecular and environmental contributors to neurological complications in sickle cell disease

Sickle cell disease (SCD) is an inherited hemoglobinopathy in which affected hemoglobin polymerizes under hypoxic conditions resulting in red cell distortion and chronic hemolytic anemia. SCD affects millions of people worldwide, primarily in Sub-Saharan Africa and the Indian subcontinent. Due to vaso-occlusion of sickled red cells within the microvasculature, SCD affects virtually every organ system and causes significant morbidity and early mortality. The neurological complications of SCD are particularly devastating and diverse, ranging from overt stroke to covert cerebral injury, including silent cerebral infarctions and blood vessel tortuosity. However, even individuals without evidence of neuroanatomical changes in brain imaging have evidence of cognitive deficits compared to matched healthy controls likely due to chronic cerebral hypoxemia and neuroinflammation. In this review, we first examined the biological contributors to SCD-related neurological complications and then discussed the equally important socioenvironmental contributors. We then discuss the evidence for neuroprotection from the two primary disease-modifying therapies, chronic monthly blood transfusions and hydroxyurea, and end with several experimental therapies designed to specifically target these complications.

Identifying patterns of neurocognitive dysfunction through direct comparison of children with leukemia, central nervous system tumors, and sickle cell disease

PURPOSE

To quantify and compare the magnitude and type of neurocognitive dysfunction in at-risk children with central nervous system (CNS) tumors, acute lymphoblastic leukemia (ALL), and sickle cell disease (SCD) using a common instrument and metric to directly compare these groups with each other.

METHODS

Fifty-three participants between the ages of 7 and 12 years (n = 27 ALL, n = 11 CNS tumor, n = 15 SCD) were enrolled and assessed using the NIH Toolbox Cognition Battery (NIHTCB). Participants with ALL or CNS tumor were 0-18 months posttherapy, while participants with SCD possessed the SS or Sβ0 genotype, took hydroxyurea, and had no known history of stroke.

RESULTS

Independent sample t-tests showed that participants with ALL and CNS tumor experienced greatest deficits in processing speed (ALL d = -0.96; CNS tumor d = -1.2) and inhibitory control and attention (ALL d = -0.53; CNS tumor d = -0.97) when compared with NIHTCB normative data. Participants with SCD experienced deficits in cognitive flexibility only (d = -0.53). Episodic memory was relatively spared in all groups (d = -0.03 to -0.32). There were no significant differences in function when groups were compared directly with each other by analysis of variance.

CONCLUSIONS

Use of a common metric to quantify the magnitude and type of neurocognitive dysfunction across at-risk groups of participants by disease shows that participants perform below age-expected norms in multiple domains and experience dysfunction differently than one another. This approach highlights patterns of dysfunction that can inform disease- and domain-specific interventions.

Social determinants of neurocognitive and academic performance in sickle cell disease

BACKGROUND

Sickle cell disease (SCD) is associated with poor neurocognitive outcomes due to biomedical and psychosocial factors. The aims of this study were to investigate associations between household and neighborhood socioeconomic status (SES) with cognitive and academic outcomes in SCD and to determine if these relationships were modified by sickle genotype, fetal hemoglobin, or age.

PROCEDURE

We prospectively recruited patients to complete a battery of neurocognitive and academic measures. Household SES was measured using the Barratt Simplified Measure of Social Status, a composite index of parent education and occupation. The Social Vulnerability Index was used to classify individuals based on social vulnerabilities at the neighborhood level.

RESULTS

Overall, 299 patients between the ages of 4 and 18 (mean = 11.4, standard deviation = 4.3) years diagnosed with SCD (57% SS/SB0 -thalassemia) completed testing. Stepwise multivariate models demonstrated that patients with low social vulnerability (i.e., high SES) at the neighborhood level displayed intelligence and math scores that were 4.70 and 7.64 points higher than those living in areas with moderate social vulnerability, respectively (p < .05). Reading performance did not differ based on neighborhood SES; however, the effect of neighborhood SES was dependent on age, such that older participants living in neighborhoods with moderate or high levels of social vulnerability displayed poorer reading scores than those with low social vulnerability (p < .05).

CONCLUSIONS

This study identified patients with SCD at higher risk of poor academic performance based on SES. Interventions addressing academic difficulties should be offered to all children with SCD, but should be emergently offered to this subpopulation.

Neuroimaging and Cognitive Function in Sickle Cell Disease: A Systematic Review

Sickle cell disease (SCD) is the most common inherited single-gene disease. Complications include chronic anaemia, reduced oxygen-carrying capability, and cerebral vasculopathy, resulting in silent cerebral infarction, stroke, and cognitive dysfunction with impairments in measures of executive function, attention, reasoning, language, memory, and IQ. This systematic review aims to investigate the association between neuroimaging findings and cognition in children with SCD. Searches of PubMed and Embase were conducted in March 2022. Studies were included if participants were <18 years, if original data were published in English between 1960 and 2022, if any genotype of SCD was included, and if the relationship between cognition and neuroimaging was examined. Exclusion criteria included case studies, editorials, and reviews. Quality was assessed using the Critical Appraisal Skills Programme Case Control Checklist. A total of 303 articles were retrieved; 33 met the eligibility criteria. The presence of overt or silent strokes, elevated blood flow velocities, abnormal functional connectivity, and decreased fMRI activation were associated with neuropsychological deficits in children with SCD when compared to controls. There is a critical need to address the disease manifestations of SCD early, as damage appears to begin at a young age. Most studies were cross-sectional, restricting the interpretation of the directionality of relationships. Future research employing longitudinal neuroimaging and neuropsychological assessments could improve our understanding of the cumulative consequences of SCD on the developing brain.

Working memory and school readiness in preschool children with sickle cell disease compared to demographically matched controls

Children diagnosed with sickle cell disease (SCD) are at risk of the development of neurobehavioural problems early in life. Specific impairments in executive function skills, including working memory, have been documented in school-aged children with SCD. These executive skills are known to strongly contribute to early academic skills and preparedness for entering kindergarten. This study examined working memory and school readiness in preschool children with SCD compared to a healthy control group matched for race, sex and parent education. A total of 84 patients diagnosed with SCD (61.9% haemoglobin [Hb]SS/HbSβ0 -thalassaemia) and 168 controls completed testing. The mean (SD) ages of patients and controls at testing were 4.53 (0.38) and 4.44 (0.65) years respectively. The SCD group performed worse than controls on measures of executive function, working memory and school readiness (p < 0.01; Cohen's D range: 0.32-0.39). Measures of working memory were associated with school readiness after accounting for early adaptive development. Multiple linear regression models among patients diagnosed with SCD revealed that college education of the primary caregiver was positively associated with school readiness (p < 0.001) after controlling for sex, genotype, age and early adaptive development. These results highlight the need to implement school readiness interventions in young children diagnosed with SCD emphasising executive function skills.

Normalization of cerebral hemodynamics after hematopoietic stem cell transplant in children with sickle cell disease

Children with sickle cell disease (SCD) demonstrate cerebral hemodynamic stress and are at high risk of strokes. We hypothesized that curative hematopoietic stem cell transplant (HSCT) normalizes cerebral hemodynamics in children with SCD compared with pre-transplant baseline. Whole-brain cerebral blood flow (CBF) and oxygen extraction fraction (OEF) were measured by magnetic resonance imaging 1 to 3 months before and 12 to 24 months after HSCT in 10 children with SCD. Three children had prior overt strokes, 5 children had prior silent strokes, and 1 child had abnormal transcranial Doppler ultrasound velocities. CBF and OEF of HSCT recipients were compared with non-SCD control participants and with SCD participants receiving chronic red blood cell transfusion therapy (CRTT) before and after a scheduled transfusion. Seven participants received matched sibling donor HSCT, and 3 participants received 8 out of 8 matched unrelated donor HSCT. All received reduced-intensity preparation and maintained engraftment, free of hemolytic anemia and SCD symptoms. Pre-transplant, CBF (93.5 mL/100 g/min) and OEF (36.8%) were elevated compared with non-SCD control participants, declining significantly 1 to 2 years after HSCT (CBF, 72.7 mL/100 g per minute; P = .004; OEF, 27.0%; P = .002), with post-HSCT CBF and OEF similar to non-SCD control participants. Furthermore, HSCT recipients demonstrated greater reduction in CBF (-19.4 mL/100 g/min) and OEF (-8.1%) after HSCT than children with SCD receiving CRTT after a scheduled transfusion (CBF, -0.9 mL/100 g/min; P = .024; OEF, -3.3%; P = .001). Curative HSCT normalizes whole-brain hemodynamics in children with SCD. This restoration of cerebral oxygen reserve may explain stroke protection after HSCT in this high-risk patient population.

Internalizing Symptoms in Adolescents With Sickle Cell Disease

OBJECTIVE

Sickle cell disease (SCD) is a genetic blood disorder that may affect patients' mood and behavior. However, measuring the prevalence of internalizing symptoms (anxiety and depression) in patients with SCD has been elusive. We assessed internalizing symptoms in adolescents with SCD to evaluate prevalence and to test whether neurocognitive performance and frequency of pain-related episodes were associated with internalizing concerns.

METHODS

One hundred eighty-five patients (57% HbSS/HbSß0-thalassemia, 43% HbSC/HbSß+-thalassemia), ages 12-18 years, received a neuropsychological evaluation as a part of a larger cohort study. Internalizing symptoms were measured using the Behavior Assessment System for Children, Second or Third Edition. Scores on the depression and anxiety scales were compared to normative values using Wilcoxon signed rank test. Spearman correlations examined associations between neurocognitive performances and internalizing symptoms. Robust multivariable regression models measured associations between internalizing symptoms and age, sex, sickle genotype, total hemoglobin, fetal hemoglobin, socioeconomic status, and frequency of pain episodes.

RESULTS

Parent- and self-reported ratings of internalizing symptoms were not elevated compared to normative expectations. Overall, 1.8% and 6.3% of the sample displayed clinically elevated symptoms of anxiety and depression based on self-report, respectively. There were no associations between internalizing symptoms and neurocognitive performance (all p > .05). In multivariable analyses, the frequency of pain episodes was positively associated with self-reported anxiety (p = .006) and parent-reported depressive symptoms (p = .017).

CONCLUSIONS

Adolescents with SCD do not report elevated internalizing symptoms compared to normative expectations. Further research is needed to examine the trajectory of internalizing symptoms and the bidirectional relationship between pain and psychosocial functioning in SCD.

Long-Term Organ Function After HCT for SCD: A Report From the Sickle Cell Transplant Advocacy and Research Alliance

Hematopoietic cell transplantation (HCT) is an established cure for sickle cell disease (SCD) supported by long-term survival, but long-term organ function data are lacking. We sought to describe organ function and assess predictors for dysfunction in a retrospective cohort (n = 247) through the Sickle cell Transplant Advocacy and Research alliance. Patients with <1-year follow-up or graft rejection/second HCT were excluded. Organ function data were collected from last follow-up. Primary measures were organ function, comparing pre- and post-HCT. Bivariable and multivariable analyses were performed for predictors of dysfunction. Median age at HCT was 9.4 years; the majority had HbSS (88.2%) and severe clinical phenotype (65.4%). Most received matched related (76.9%) bone marrow (83.3%) with myeloablative conditioning (MAC; 57.1%). Acute and chronic graft-versus-host disease (GVHD) developed in 24.0% and 24.8%. Thirteen patients (5.3%) died ≥1 year after HCT, primarily from GVHD or infection. More post-HCT patients had low ejection or shortening fractions than pre-HCT (0.6% → 6.0%, P = .007 and 0% → 4.6%, P = .003). The proportion with lung disease remained stable. Eight patients (3.2%) had overt stroke; most had normal (28.3%) or stable (50.3%) brain magnetic resonance imaging. On multivariable analysis, cardiac dysfunction was associated with MAC (odds ratio [OR] = 2.71; 95% confidence interval [CI], 1.09-6.77; P = .033) and severe acute GVHD (OR = 2.41; 95% CI, 1.04-5.62; P = .041). Neurologic events were associated with central nervous system indication (OR = 2.88; 95% CI, 2.00-4.12; P < .001). Overall organ dysfunction was associated with age ≥16 years (OR = 2.26; 95% CI, 1.35-3.78; P = .002) and clinically severe disease (OR = 1.64; 95% CI, 1.02-2.63; P = .043). In conclusion, our results support consideration of HCT at younger age and use of less intense conditioning.

The Development of Neuroimaging Biomarkers for Cognitive Decline in Sickle Cell Disease

Sickle cell disease (SCD) is complicated by neurologic complications including vasculopathy, hemorrhagic or ischemic overt stroke, silent cerebral infarcts and cognitive dysfunction. Patients with SCD, even in the absence of vasculopathy or stroke, have experience cognitive dysfunction that progresses with age. Transcranial Doppler ultrasound and structural brain MRI are currently used for primary and secondary stroke prevention, but laboratory or imaging biomarkers do not currently exist that are specific to the risk of cognitive dysfunction in patients with SCD. Recent investigations have used advanced MR sequences assessing cerebral hemodynamics, white matter microstructure and functional connectivity to better understand the pathophysiology of cognitive decline in SCD, with the long-term goal of developing neuroimaging biomarkers to be used in risk prediction algorithms and to assess the efficacy of treatment options for patients with SCD.

Stroke in sickle cell disease and the promise of recent disease modifying agents

Sickle cell disease (SCD) is an inherited hemoglobinopathy affecting approximately 100,000 individuals in the United States. Cerebrovascular disease is among the most common and debilitating complications of SCA, with 53% experiencing silent cerebral infarct by age 30 and 3.8% experiencing overt stroke by age 40 years. This review highlights the burden of cerebrovascular disease in SCD, including both stroke and silent cerebral infarct (SCI). We then discuss the pathophysiology of stroke and cerebral fat embolism in the absence of a patent foramen ovale. This review also reveals that options for primary and secondary stroke prevention in SCD are still limited to hydroxyurea and blood transfusion, and that the role of aspirin and anticoagulation in SCD stroke has not been adequately studied. Limited data suggest that the novel disease-modifying agents for SCD management may improve renal dysfunction, leg ulcers, and lower the abnormally high TCD flow velocity. Further research is urgently needed to investigate their role in stroke prevention in SCD, as these novel agents target the main stroke contributors in SCD - hemolysis and vaso-occlusion. This literature review also explores the role of healthcare disparities in slowing progress in SCD management and research in the United States, highlighting the need for more investment in patient and clinician education, SCD management, and research.

Neuropsychological, behavioral, and quality-of-life outcomes in children and adolescents with sickle cell disease treated with nonmyeloablative matched sibling donor hematopoietic cell transplantation: A case series

BACKGROUND/OBJECTIVES

Despite advances in the treatment of sickle cell disease (SCD), cerebrovascular and cognitive insults can have lifelong consequences. Hematopoietic cell transplantation (HCT) is an established curative therapy, and recent studies have demonstrated efficacy with reduced toxicity nonmyeloablative (NMA) regimens, but little is known about neuropsychological outcomes. The objective of this study was to describe neuropsychological, behavioral, and quality-of-life outcomes with medical correlates in children with SCD who received an NMA matched sibling donor (MSD) HCT.

DESIGN/METHODS

Retrospective cohort analysis of nine recipients with hemoglobin SS SCD who underwent MSD HCT using the National Institutes of Health (NIH) NMA protocol.

RESULTS

Mean full-scale intellectual functioning (FSIQ) was average pre-HCT (FSIQ = 92.1, SD 9.0; n = 8) and 2 years post-HCT (mean FSIQ = 96.6; SD 11.1; N = 9). Neuropsychological functioning was largely average across all cognitive domains, and no pre/post-HCT differences were found to be statistically significant given the small sample size. However, effect sizes revealed moderate improvements in processing speed (Cohen's d = .72) and verbal memory (Cohen's d = .60) post-HCT, and declines in measures of attention (Cohen's d = -.54) and fine motor speed and dexterity (Cohen's d = -.94). Parents endorsed better quality of life (Cohen's d = .91), less impact of SCD on their family, and less worry about their child's future (Cohen's d = 1.44).

CONCLUSION

Neuropsychological functioning in a sample of children and adolescents treated uniformly with NMA MSD HCT remained stable or improved in most cognitive domains, and improvements in quality of life and family functioning were observed.

Early hydroxyurea use is neuroprotective in children with sickle cell anemia

Children with sickle cell disease (SCD) who began hydroyxurea before age five years scored no differently on a measure of cognitive funciton than age, sex, and race-matched unaffected peers.

A case-control and seven-year longitudinal neurocognitive study of adults with sickle cell disease in Ghana

Ageing in sickle cell disease (SCD) is associated with a myriad of end-organ complications, including cerebrovascular damage and cognitive impairment (CI). Although CI is very common in SCD, little is known about cognitive functioning and how it changes with age. This study examines cognitive patterns of 63 adults with SCD and 60 non-SCD, age- and education-matched controls in Ghana. Of those adults with SCD, 34 completed the neuropsychological battery at baseline and again seven years later. In cross-sectional data, adults with SCD performed worse than controls in all cognitive test domains (p < 0.01 for all). The seven-year follow-up data showed that the group exhibited a significant decline in visuospatial abilities (ranging from Cohen's d = 1.40 to 2.38), and to a lesser extent, in processing speed and executive functioning. Exploratory analyses showed a significant time-by-education interaction, indicating that education may be protective from decline in cognitive performance. These findings have implications for clinical practice. Early neuropsychological surveillance coupled with early assessment and remedial programmes will provide avenues for enhancing the quality of life of adults living with SCD in Ghana.

Quantification of Silent Cerebral Infarction on High-Resolution FLAIR and Cognition in Sickle Cell Anemia

Research in sickle cell anemia (SCA) has used, with limited race-matched control data, binary categorization of patients according to the presence or absence of silent cerebral infarction (SCI). SCI have primarily been identified using low-resolution MRI, with radiological definitions varying in lesion length and the requirement for abnormality on both fluid attenuated inversion recovery (FLAIR) and T1-weighted images. We aimed to assess the effect of published SCI definitions on global, regional, and lobar lesion metrics and their value in predicting cognition. One hundred and six patients with SCA and 48 controls aged 8-30 years underwent 3T MRI with a high-resolution FLAIR sequence and Wechsler cognitive assessment. Prevalence, number, and volume of lesions were calculated using a semi-automated pipeline for SCI defined as: (1) Liberal: any length (L-SCI); (2) Traditional: >3 mm in greatest dimension (T-SCI); (3) Restrictive; >3 mm in greatest dimension with a corresponding T1-weighted hypo-intensity (R-SCI). Globally, as hypothesized, there were large effects of SCI definition on lesion metrics in patients and controls, with prevalence varying from 24-42% in patients, and 4-23% in controls. However, contrary to hypotheses, there was no effect of any global metric on cognition. Regionally, there was a consistent distribution of SCI in frontal and parietal deep and juxta-cortical regions across definitions and metrics in patients, but no consistent distribution in controls. Effects of regional SCI metrics on cognitive performance were of small magnitude; some were paradoxical. These findings expose the challenges associated with the widespread use of SCI presence as a biomarker of white-matter injury and cognitive dysfunction in cross-sectional high-resolution MRI studies in patients with SCA. The findings indicate that with high-resolution MRI: (1) radiological definitions have a large effect on resulting lesion groups, numbers, and volumes; (2) there is a non-negligible prevalence of lesions in young healthy controls; and (3) at the group-level, there is no cross-sectional association between global lesion metrics and general cognitive impairment irrespective of lesion definition and metric. With high-resolution multi-modal MRI, the dichotomy of presence or absence of SCI does not appear to be a sensitive biomarker for the detection of functionally significant pathology; the search for appropriate endpoints for clinical treatment trials should continue.

Sluggish Cognitive Tempo in Pediatric Sickle Cell Disease

Background

Sickle cell disease (SCD) imparts risk for a range of neurodevelopmental and neurocognitive disorders. Sluggish cognitive tempo (SCT) is a distinct syndrome that often co-occurs with attention-deficit/hyperactivity disorder (ADHD) but has not been described in SCD. We investigated the reliability and validity of a SCT measure in SCD and examined associations with biopsychosocial risk factors and functional outcomes.

Materials and Methods

Caregivers (n = 85) of children with SCD ages 7-16 reported on socio-demographics and the Kiddie-Sluggish Cognitive Tempo (K-SCT) measure, Behavior Rating Inventory of Executive Function, and Conners 3. Disease-related characteristics were extracted from health records.

Results

The K-SCT demonstrated excellent internal consistency (α = 0.92) and test-retest reliability (r = 0.82, p < 0.001). K-SCT scores were correlated with ADHD-Inattention (r = 0.64, p < 0.001) and ADHD-Hyperactive/Impulsive (r = 0.46, p < 0.001) scores, as well as functional outcomes, including learning problems (r = 0.69, p < 0.001). In multivariate analyses controlling for ADHD symptoms, SCT accounted for unique variance in learning (b = 9.67, p < 0.01) and executive functioning (b = 5.93, p < 0.01). Nearly all participants (93%) with elevated levels of co-occurring SCT and ADHD-Inattention symptoms had significant learning problems.

Conclusion

The K-SCT is a reliable and valid measure of SCT in SCD. SCT symptoms are associated with learning difficulties even after controlling for ADHD symptoms. Further research is needed to understand the biopsychosocial factors that lead to SCT symptoms in SCD and examine long-term implications of SCT.

Medical and Non-medical Costs of Sickle Cell Disease and Treatments from a US Perspective: A Systematic Review and Landscape Analysis

BACKGROUND

Sickle cell disease (SCD) is a complex genetic disorder that manifests in infancy and progresses throughout life in the form of acute and chronic complications. As the upfront costs of potentially curative, genetic therapies will likely be high, an assessment and comprehensive characterization of the medical and non-medical cost burden will inform future decision making.

OBJECTIVE

We sought to systematically summarize the existing literature surrounding SCD medical and non-medical costs.

METHODS

We searched MEDLINE and EMBASE (2008-2020) and identified US-based studies that detailed medical or non-medical costs. Eligible studies provided empirical estimates about any aspect of cost or SCD individuals of all ages and their caregivers. Study quality was assessed using the Newcastle-Ottawa Scale, and costs were adjusted to 2019 US$.

RESULTS

Search queries returned 479 studies, with 342 from medical burden searches and 137 from non-medical burden searches, respectively. Herein, we report the results of the 40 studies that contained relevant cost information: 39 detailed medical costs and 1 detailed non-medical costs. Costs were higher for SCD patients when compared with non-SCD individuals (cost difference range: $6636-$63,436 annually). The highest medical cost component for SCD patients was inpatient ($11,978-$59,851 annually), followed by outpatient and then pharmacy. No studies characterized the cost burden throughout the lifetime disease trajectory of an SCD individual, and no studies captured caregiver or productivity costs.

CONCLUSION

Our results reveal an incomplete characterization of medical and non-medical costs within SCD. A deeper understanding of the medical and non-medical cost burden requires completion of additional studies that capture the burden across the patient's lifetime, in addition to expression of the impact of existing and emergent health technologies on disease trajectory.

Venous cerebral blood flow quantification and cognition in patients with sickle cell anemia

Prior studies have described high venous signal qualitatively using arterial spin labelling (ASL) in patients with sickle cell anemia (SCA), consistent with arteriovenous shunting. We aimed to quantify the effect and explored cross-sectional associations with arterial oxygen content (CaO2), disease-modifying treatments, silent cerebral infarction (SCI), and cognitive performance. 94 patients with SCA and 42 controls underwent cognitive assessment and MRI with single- and multi- inflow time (TI) ASL sequences. Cerebral blood flow (CBF) and bolus arrival time (BAT) were examined across gray and white matter and high-signal regions of the sagittal sinus. Across gray and white matter, increases in CBF and reductions in BAT were observed in association with reduced CaO2 in patients, irrespective of sequence. Across high-signal sagittal sinus regions, CBF was also increased in association with reduced CaO2 using both sequences. However, BAT was increased rather than reduced in patients across these regions, with no association with CaO2. Using the multiTI sequence in patients, increases in CBF across white matter and high-signal sagittal sinus regions were associated with poorer cognitive performance. These novel findings highlight the utility of multiTI ASL in illuminating, and identifying objectively quantifiable and functionally significant markers of, regional hemodynamic stress in patients with SCA.

Cerebral oxygen metabolic stress is increased in children with sickle cell anemia compared to anemic controls

Patients with sickle cell anemia (SCA) experience cerebral metabolic stress with an increase in oxygen extraction fraction (OEF) to compensate for reduced oxygen carrying capacity due to anemia. It remains unclear if anemia alone drives this metabolic stress. Using MRI, we collected voxel-wise OEF measurements to test our hypothesis that OEF would be elevated in anemic controls without SCA (AC) compared to healthy controls (HC), but OEF would be even higher in SCA compared to AC. Brain MRIs (N = 159) were obtained in 120 participants (34 HC, 27 AC, 59 SCA). While hemoglobin was lower in AC versus HC (p < 0.001), hemoglobin was not different between AC and SCA cohorts (p = 0.459). Whole brain OEF was higher in AC compared to HC (p < 0.001), but lower compared to SCA (p = 0.001). Whole brain OEF remained significantly higher in SCA compared to HC (p = 0.001) while there was no longer a difference between AC versus HC (p = 0.935) in a multivariate model controlling for age and hemoglobin. OEF peaked within the border zone regions of the brain in both SCA and AC cohorts, but the volume of white matter with regionally elevated OEF in AC was smaller (1.8%) than SCA (58.0%). While infarcts colocalized within regions of elevated OEF, more SCA participants had infarcts than AC (p < 0.001). We conclude that children with SCA experience elevated OEF compared to AC and HC after controlling for the impact of anemia, suggesting that there are other pathophysiologic factors besides anemia contributing to cerebral metabolic stress in children with SCA.

Burden of central nervous system complications in sickle cell disease: A systematic review and meta-analysis

Sickle cell disease (SCD) patients are at high risk of central nervous system (CNS) complications and may experience significant morbidity. The study was conducted to describe the comprehensive burden of SCD-related CNS complications and to identify patient-reported outcome (PRO) instruments for future research. The review included 32 studies published from January 2000 to 2020, evaluating humanistic and economic outcomes. Twenty-three studies reported humanistic outcomes, 16 of which measured cognitive function using Wechsler Intelligence Scales. A meta-analysis was conducted, finding full-scale intelligence quotient (IQ) was significantly lower in: overt stroke versus controls: -12.6 (p < .001); silent cerebral infarct (SCI) versus controls: -5.7 (p < .001); overt stroke versus SCI: -9.4 (p = .008); and any event versus controls: -7.6 (p < .001). This review quantified the cognitive deficits associated with CNS complications in pediatric SCD populations and highlights the need for improved prevention/treatment. As PRO evidence was limited, we discussed areas for future research.

Fetal hemoglobin modulates neurocognitive performance in sickle cell anemia✰,✰✰

PURPOSE OF THE STUDY

Fetal hemoglobin (HbF) is a modifier of the clinical and hematologic phenotype of sickle cell anemia (SCA). Three quantitative trait loci (QTL) modulate HbF expression. The neurocognitive effects of variants in these QTL have yet to be explored. We evaluated the relation between 11 SNPs in the three HbF QTL: BCL11A, MYB, the HBB gene cluster, and full-scale intelligence (IQ) in SCA.

PATIENTS AND METHODS

The prospective longitudinal cohort study, Sickle Cell Clinical Research and Intervention Program, was used as a discovery cohort (n = 166). The genotypes for 11 SNPs were extracted through whole genome sequencing and were analyzed using an additive model. A polygenic score for HbF (PGS^HbF) integrating the numbers of low HbF alleles from 11 SNPs was analyzed as a continuous variable. The Cooperative Study of Sickle Cell Disease (n = 156) and the Silent Cerebral Infarction Transfusion (n = 114) Trial were used as two independent replication cohorts. Benjamini and Hochberg approach was used to calculate false discovery rate adjusted p-value (pFDR).

RESULTS

HbF was positively associated with IQ (minimum raw p = 0·0018) at pFDR<0·05. HbF mediated the relationship between two BCL11A SNPs, rs1427407 and rs7606173, HBS1L-MYB: rs9494142, and PGS^HbF with IQ (minimum raw p = 0·0035) at pFDR<0·05.

CONCLUSION

As the major modulator of the severity of SCA, HbF also influences neurocognition, which is done through mediation of its QTL. These findings have implications for early identification of neurocognitive risk and targeted intervention.

Neurocognitive functioning in preschool children with sickle cell disease

BACKGROUND

Children with sickle cell disease (SCD) experience neurodevelopmental delays; however, there is limited research with preschool-age children. This study examined neurocognitive risk and protective factors in preschoolers with SCD.

PROCEDURE

Sixty-two patients with SCD (60% HbSS/HbSβ⁰ -thalassemia; 40% HbSC/HbSβ⁺ -thalassemia) between the ages of 3 and 6 years (mean = 4.77 years) received a neuropsychological evaluation as routine systematic surveillance. Patients were not selected for disease severity, prior central nervous system findings, or existing cognitive concerns. Thirty-four patients (82% HbSS/HbSβ⁰ -thalassemia) were prescribed hydroxyurea (HU) at the time of their neuropsychological evaluation. On average, these patients had been prescribed HU at 2.15 (standard deviation = 1.45) years of age. The average dose was 28.8 mg/kg/day. Besides genotype, there were no group differences in medical or demographic factors based on HU treatment status.

RESULTS

Patients with HbSS/HbSβ⁰ -thalassemia scored below normative expectations on measures of intelligence, verbal comprehension, and school readiness (false discovery rate-adjusted p-value [p_FDR ] < .05). Age, sickle genotype, and HU treatment exposure were not associated with measured neurocognitive outcomes (p_FDR  > .05). Greater social vulnerability at the community level was associated with poorer performance on measures of intellectual functioning, verbal comprehension, visuomotor control, and school readiness, as well as parent report of executive dysfunction (p_FDR  < .05). Greater household socioeconomic status was positively associated with academic readiness.

CONCLUSIONS

Preschoolers with severe SCD (HbSS/HbSβ⁰ -thalassemia) perform below age expectations on measures of intelligence and academic readiness. Sociodemographic factors were stronger drivers of neurocognitive performance than disease severity or disease-modifying treatment. Neurodevelopmental interventions targeting the home and broader community environment are needed.

Effect of age, cerebral infarcts, vasculopathy and haemoglobin on cognitive function, in Tanzanian children with sickle cell anaemia

BACKGROUND

Developmental difficulties in many cognitive domains are common in children with sickle cell anaemia (SCA). Children with stroke are most affected but delayed or atypical cognitive function has been reported in children with SCA and silent infarcts (SCI), vasculopathy, and normal brain MRI. However, very few studies of cognition have been conducted in Africa, a continent with 75% of the SCA burden. We therefore investigated cognitive profiles in Tanzanian children with SCA and examined the impact of age, SCI, vasculopathy, and haemoglobin concentration (Hb).

METHODS

Children aged 6-16 years with and without SCA were eligible for this cross-sectional study. Cognitive assessment was performed using Raven's Matrices, assessing fluid, non-verbal intelligence and subtests from the Wechsler Intelligence Scales for Children (WISC-IV), assessing processing speed (PS), perceptual reasoning (PR), and working memory (WM) as these tests are less culture-bound. Magnetic resonance imaging (MRI) and angiography (MRA) were also completed to assess the presence of SCI and vasculopathy. Hb was collected in both SCA children and their non-SCA siblings.

RESULTS

Seventy-three children with SCA and 71 healthy siblings (Mean_ages 11.9, SD = 2.8 and 11.1, SD = 2.9 years respectively) were recruited. Compared with healthy siblings, children with SCA had lower PS (Mean_diff 7.35 points; p = .002). Older children had higher performance scores on all tests in relation to their ages. Lowest cognitive scores were observed on the PS subtest, where patients with SCI (SCI+) had lowest mean values as compared to children with no SCI (SCI-) and healthy siblings (i.e., SCI+ < SCI- < healthy siblings, p = .028). On post-hoc analysis the difference was between SCI+ and healthy siblings SCI+ < non-SCA siblings (p = .015); there was no difference between SCI+ and SCI- patient groups. PS was significantly lower in SCA patients with no vasculopathy as compared to healthy siblings. The mean difference from healthy siblings was -8.352 and -0.752 points for VASC- and VASC + respectively (p = .004). There was a significant positive effect of Hb on PSI (p = .001) in both patients and controls and a trend level significant positive effect of Hb on PR (p = .050) and WM (p = .051).

CONCLUSION

In this Tanzanian study, cognitive performance was reduced in children with SCA with or without SCI on MRI or vasculopathy. Cognitive performance improved with increasing age. Lower Hb was associated with lower cognitive performance in both patients with SCA and their non-SCA siblings. SCI and vasculopathy do not appear to have an impact on cognitive function.

Association between hearing impairment, school performance and cognitive function in children and adolescents with sickle cell disease

OBJECTIVE

To investigate the association among hearing impairment, school performance, and cognitive function in children and adolescents with sickle cell disease.

METHODS

Thirty-one participants with sickle cell disease (SCD) and 31 healthy participants in the control-comparison group (CG), both aged 8-17 years underwent auditory system evaluation (pure tone audiometry and acoustic reflex), were screened for the risks of (central) auditory processing disorder and dysfunction of cognitive function using the Scale of Auditory Behaviors (SAB) and the Mini-Mental State Examination (MMSE), respectively, and were interviewed to obtain clinical data and data on school performance.

RESULTS

In the SCD group, eight (25.8%) participants presented with sensorineural hearing loss (SNHL). The group with SCD and SNHL presented a higher occurrence of poor school performance than the group of participants with SCD without SNHL (p= 0.016). The MMSE score for aspects related to attention and calculation in the SCD group with SNHL was lower than in the SCD group without SNHL (p= 0.016). In the SAB, the SCD group with SNHL presented a lower score than the SCD group without SNHL in aspects related to academic performance and attention.

CONCLUSION

Hearing impairment in children and adolescents with SCD, specifically SNHL, is associated with poor school performance and enhances the risk of cognitive impairment in terms of attention and calculation.

Economic evaluation of regular transfusions for cerebral infarct recurrence in the Silent Cerebral Infarct Transfusion Trial

Children with preexisting silent cerebral infarcts on regular transfusion therapy had 50% lower hospitalization costs than standard care.

The incremental cost-effectiveness ratio for transfusion therapy to prevent infarct recurrence was $22 025 for every infarct prevented.

In 2020, the American Society of Hematology published evidence-based guidelines for cerebrovascular disease in individuals with sickle cell anemia (SCA). Although the guidelines were based on National Institutes of Health–sponsored randomized controlled trials, no cost-effectiveness analysis was completed for children with SCA and silent cerebral infarcts. We conducted a cost-effectiveness analysis comparing regular blood transfusion vs standard care using SIT (Silent Cerebral Infarct Transfusion) Trial participants. This analysis included a modified societal perspective with direct costs (hospitalization, emergency department visit, transfusion, outpatient care, and iron chelation) and indirect costs (special education). Direct medical costs were estimated from hospitalizations from SIT hospitals and unlinked aggregated hospital and outpatient costs from SIT sites by using the Pediatric Health Information System. Indirect costs were estimated from published literature. Effectiveness was prevention of infarct recurrence. An incremental cost-effectiveness ratio using a 3-year time horizon (mean SIT Trial participant follow-up) compared transfusion vs standard care. A total of 196 participants received transfusions (n = 90) or standard care (n = 106), with a mean age of 10.0 years. Annual hospitalization costs were reduced by 54% for transfusions vs standard care ($4929 vs $10 802), but transfusion group outpatient costs added $22 454 to $137 022 per year. Special education cost savings were $2634 over 3 years for every infarct prevented. Transfusion therapy had an incremental cost-effectiveness ratio of $22 025 per infarct prevented. Children with preexisting silent cerebral infarcts receiving blood transfusions had lower hospitalization costs but higher outpatient costs, primarily associated with the oral iron chelator deferasirox. Regular blood transfusion therapy is cost-effective for infarct recurrence in children with SCA. This trial is registered at www.clinicaltrials.gov as #NCT00072761.

Academic Performance of Children With Sickle Cell Disease in the United States: A Meta-Analysis

Background: Students with sickle cell disease are at risk for poor academic performance due to the combined and/or interactive effects of environmental, psychosocial, and disease-specific factors. Poor academic performance has significant social and health consequences. Objective: To study academic achievement and attainment in children with sickle cell disease in the United States. Design: Medline, Embase, SCOPUS, CINAHL, ERIC, and PsycINFO were searched for peer-reviewed articles. Studies of children (ages 5-18) diagnosed with sickle cell disease of any genotype reporting academic achievement (standardized tests of reading, math, and spelling) or attainment (grade retention or special education) outcomes were included. Outcomes were analyzed using a random effects model. Achievement scores were compared to within study controls or normative expectations. Prevalence of grade retention and special education services were compared to national (United States) estimates for Black students. Age at assessment and overall IQ were evaluated separately for association with reading and mathematics scores. Subgroup analyses of reading and math scores were analyzed by cerebral infarct status (no cerebrovascular accident, silent infarct, stroke). Results: There were 44 eligible studies. Students with sickle cell disease scored 0.70, 0.87, and 0.80 (p < 0.001) SD below normative expectations on measures of reading, mathematics, and spelling, respectively. Compared to unaffected sibling and/or healthy controls (k = 8, n = 508), reading and math scores were 0.40 (p = 0.017) and 0.36 (p = 0.033) SD below expectations. Grade retention was approximately 10 times higher in students with sickle cell disease than Black students nationally. Intellectual functioning explained 97.3 and 85.8% of the variance in reading and mathematics performance, respectively (p < 0.001). Subgroup analyses revealed significant differences in reading (p = 0.034) and mathematics (p < 0.001) based on infarct status, with lower performance associated with presence of a silent infarct or stroke. Conclusion: Students with sickle cell disease demonstrate notable academic difficulties and are at high risk for grade retainment. Development of academic interventions and increased access to school support services are needed for this vulnerable population. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020179062.

Navigating Ethical Challenges for Pediatric Sickle Cell Pain Management in the Context of the Opioid Epidemic

OBJECTIVES

The aim was to describe the impact of the opioid epidemic on pain management practices in pediatric sickle cell disease (SCD) and propose a conceptual framework for navigating ethical decision-making in pediatric sickle cell pain management.

METHODS

A review of the literature on ethical challenges in the management of sickle cell pain was conducted and considered in the context of the opioid epidemic and psychosocial factors affecting youth with SCD. The Integrated Ethical Framework for Pain Management (IEFPM) was applied to pediatric sickle cell pain management using a clinical case example.

RESULTS

Implicit bias, health-related stigma, and potential neurocognitive impairment all present unique challenges in ethical decision-making for youth with SCD. National guidelines for prescribing opioid medication may complicate providers' clinical decision-making and affect their sickle cell pain management practices. The IEFPM was found to be applicable to ethical decision-making for pediatric sickle cell pain and captures both patient-related and provider-related aspects of clinical pain management.

DISCUSSION

The opioid epidemic has exacerbated existing ethical challenges for pain management among youth with SCD. The IEFPM provides a conceptual model that can be integrated into health care settings to facilitate ethical decision-making and promote greater health equity in the clinical management of pediatric sickle cell pain.

Study of montelukast in children with sickle cell disease (SMILES): a study protocol for a randomised controlled trial

Background

Young children with sickle cell anaemia (SCA) often have slowed processing speed associated with reduced brain white matter integrity, low oxygen saturation, and sleep-disordered breathing (SDB), related in part to enlarged adenoids and tonsils. Common treatments for SDB include adenotonsillectomy and nocturnal continuous positive airway pressure (CPAP), but adenotonsillectomy is an invasive surgical procedure, and CPAP is rarely well-tolerated. Further, there is no current consensus on the ability of these treatments to improve cognitive function. Several double-blind, randomised controlled trials (RCTs) have demonstrated the efficacy of montelukast, a safe, well-tolerated anti-inflammatory agent, as a treatment for airway obstruction and reducing adenoid size for children who do not have SCA. However, we do not yet know whether montelukast reduces adenoid size and improves cognition function in young children with SCA.

Methods

The Study of Montelukast In Children with Sickle Cell Disease (SMILES) is a 12-week multicentre, double-blind, RCT. SMILES aims to recruit 200 paediatric patients with SCA and SDB aged 3–7.99 years to assess the extent to which montelukast can improve cognitive function (i.e. processing speed) and sleep and reduce adenoidal size and white matter damage compared to placebo. Patients will be randomised to either montelukast or placebo for 12 weeks. The primary objective of the SMILES trial is to assess the effect of montelukast on processing speed in young children with SCA. At baseline and post-treatment, we will administer a cognitive evaluation; caregivers will complete questionnaires (e.g. sleep, pain) and measures of demographics. Laboratory values will be obtained from medical records collected as part of standard care. If a family agrees, patients will undergo brain MRIs for adenoid size and other structural and haemodynamic quantitative measures at baseline and post-treatment, and we will obtain overnight oximetry.

Discussion

Findings from this study will increase our understanding of whether montelukast is an effective treatment for young children with SCA. Using cognitive testing and MRI, the SMILES trial hopes to gain critical knowledge to help develop targeted interventions to improve the outcomes of young children with SCA.

Trial registration

ClinicalTrials.govNCT04351698. Registered on April 17, 2020. European Clinical Trials Database (EudraCT No. 2017-004539-36). Registered on May 19, 2020

Effects of hydroxyurea on brain function in children with sickle cell anemia

INTRODUCTION

Sickle cell anemia (SCA) results in numerous adverse effects on the brain, including neurocognitive dysfunction. Hydroxyurea has been utilized extensively for management of SCA, but its effects on brain function have not been established.

METHODS

We examined prospectively the effects of 1 year of treatment with hydroxyurea on brain function in children with SCA (HbSS/HbSβ⁰ -thalassemia) by baseline and exit evaluations, including comprehensive neurocognitive testing, transcranial Doppler ultrasound (TCD), and brain MRI (silent cerebral infarcts [SCI], gray matter cerebral blood flow [GM-CBF], and blood oxygen level-dependent [BOLD] signal from visual stimulation).

RESULTS

Nineteen patients with SCA, mean age 12.4 years (range 7.2-17.8), were evaluated. At baseline, subjects had these mean values: full-scale IQ (FSIQ) 82.8, TCD velocity 133 cm/s, GM-CBF 64.4 ml/100 g/min, BOLD signal 2.34% increase, and frequency of SCI 47%. After 1 year of hydroxyurea, there were increases in FSIQ (+2, p = .059) and reading passage comprehension (+4, p = .033), a significant decrease in TCD velocity (-11 cm/s, p = .007), and no significant changes in GM-CBF, BOLD, or SCI frequency. Hemoglobin F (HbF) was associated with passage comprehension, hemoglobin with lower TCD velocity, and lower GM-CBF with greater working memory. Higher BOLD signal was associated with higher processing speed and lower TCD velocity with higher math fluency.

DISCUSSION

Improvements in neurocognition and decreased TCD velocity following 1 year of treatment support hydroxyurea use for improving neurocognitive outcomes in SCA. Understanding the mechanisms of benefit, as indicated by relationships of neurocognitive function with HbF, hemoglobin, and CBF, requires further evaluation.

Developmental screening of three-year-old children with sickle cell disease compared to controls

We previously found that neurodevelopmental deficits commonly occurred in three-year-olds with sickle cell disease (SCD), but clinical significance was uncertain because a comparison group was lacking. Our objective in the current study was to prospectively compare neurodevelopment in three-year-old children with SCD to an age-appropriate control group. The Brigance Preschool Screen II is a neurodevelopmental screening examination which can be administered in 15-20 min. SCD patients (Group 1) were compared with community controls of similar age and ethnicity enrolled in daycare/preschool (Group 2). SCD patients who were receiving hydroxycarbamide treatment were also compared (Group 3). Two hundred forty-five three-year-olds were evaluated: Group 1, 111; Group 2, 114; and Group 3, 20. The below cut-off rate on the Brigance test was higher in Group 1 (73%) than in Group 2 (61%; P = 0·04). In multivariate analysis of Group 1 patients, only lower household income and more persons living in the home were independent predictors of this. Patients with SCD and matched controls had high rates of 'failing' the Brigance test. The below cut-off rate in untreated children with SCD was associated with low household income and increased number of persons living in the home.

Hydroxyurea Use Associated with Nonverbal and Executive Skills in Sickle Cell Anemia

OBJECTIVE

Hydroxyurea (HU) is used in children with sickle cell disease (SCD) to increase fetal hemoglobin (HF), contributing to a decrease in physical symptoms and potential protection against cerebral microvasculopathy. There has been minimal investigation into the association between HU use and cognition in this population. This study examined the relationship between HU status and cognition in children with SCD.

METHODS

Thirty-seven children with SCD HbSS or HbS/β0 thalassaemia (sickle cell anemia; SCA) ages 4:0-11 years with no history of overt stroke or chronic transfusion completed a neuropsychological test battery. Other medical, laboratory, and demographic data were obtained. Neuropsychological function across 3 domains (verbal, nonverbal, and attention/executive) was compared for children on HU (n = 9) to those not taking HU (n = 28).

RESULTS

Children on HU performed significantly better than children not taking HU on standardized measures of attention/executive functioning and nonverbal skills. Performance on verbal measures was similar between groups.

CONCLUSIONS

These results suggest that treatment with HU may not only reduce physical symptoms, but may also provide potential benefit to cognition in children with SCA, particularly in regard to attention/executive functioning and nonverbal skills. Replication with larger samples and longitudinal studies are warranted.

Neurologic and Cognitive Outcomes in Sickle Cell Disease from Infancy through Adolescence

Children with sickle cell disease (SCD) are at risk for neurologic and cognitive complications beginning in early childhood. Current treatment for SCD focuses on primary prevention of complications, such as hydroxyurea for prevention of pain and acute chest syndrome, and chronic transfusion therapy for children who are at high risk for strokes. In this article, the prevalence, pathophysiology, and available interventions to prevent and treat neurologic and cognitive complications of SCD will be reviewed.

Hydroxyurea treatment and neurocognitive functioning in sickle cell disease from school age to young adulthood

Neurocognitive impairment is common in sickle cell disease (SCD) and is associated with significant functional limitations. In a cross-sectional analysis, we examined the association between hydroxyurea (HU) treatment and neurocognitive functioning from school-age to young adulthood in individuals with SCD. A total of 215 patients with HbSS/HbSβ⁰ -thalassaemia (71% HU treated) and 149 patients with HbSC/HbSβ⁺ -thalassaemia (20% HU treated) completed neurocognitive measures at one of four developmental stages: school-age (age 8-9 years), early adolescence (age 12-13 years), late adolescence (age 16-17 years) and young adulthood (ages 19-24 years). For participants with multiple assessments, only the most recent evaluation was included. In multivariable analysis adjusted for social vulnerability, HU treatment and sex, older age was associated with a reduction in overall intelligence quotient (IQ) of 0·55 points per year of life [standard error (SE) = 0·18, false discovery rate adjusted P value (PFDR) = 0.01] for patients with HbSS/HbSβ⁰ -thalassaemia. Earlier initiation of HU (n = 152) in HbSS/HbSβ⁰ -thalassaemia was associated with higher scores on neurocognitive measures across most domains, including IQ [estimate (SE) 0·77 (0·25)/year, PFDR = 0·01], after adjusting for social vulnerability, sex and treatment duration. These results support the early use of HU to limit the detrimental neurocognitive effects of SCD, while highlighting the need for additional measures to further mitigate neurocognitive deterioration.

Anemia falciforme e as consequências nas funções executivas

A anemia falciforme (AF) é reconhecida pela Organização Mundial de Saúde (OMS) como um problema global de saúde pública, sendo a mais comum dentre as doenças hereditárias no Brasil. O objetivo principal desta pesquisa é investigar o desempenho das funções executivas em crianças com anemia falciforme residentes na região Nordeste do país. Participaram 134 crianças, na faixa etária de 6-11 anos, sendo 60 do grupo clínico e 74 do grupo não clínico. Os instrumentos utilizados foram FDT – Teste dos Cinco Dígitos; Teste de Trilhas; Torre de Londres e subteste Dígitos. Os dados foram analisados pelo U de Mann-Whitney indicando diferenças estatísticas (p<0,05) entre os grupos em todos os instrumentos utilizados, exceto no Torre de Londres. Propõe-se que estudos futuros com crianças portadoras de AF detenham-se na intervenção cognitiva de funções afetadas abrangendo pré-escolares e estudantes do ensino fundamental.

Cognitive Functioning and Educational Support Plans in Youth With Sickle Cell Disease

Children with sickle cell disease (SCD) face academic challenges because of direct and indirect disease-related events. This study examined the proportion of youth with SCD with educational plans and whether cognitive functioning is associated with educational support. Ninety-one youth (7 to 16 y) with SCD completed the WISC-V; caregivers reported educational support (504 Plan/Individualized Education Program) and completed the Behavior Rating Inventory of Executive Function. χ2 square and t test analyses explored whether overall intelligence (full-scale intelligence quotient [FSIQ]), relative weaknesses in processing speed and working memory (> 1SD below FSIQ), and parent-reported executive functioning were associated with educational plans. Participants with a FSIQ<90 were more likely to have support (74%) compared with youth with a FSIQ≥90 (47%; P=0.012). Those with FSIQ≥90 and FSIQ=80 to 89 were less likely to have support (47%, 58%, respectively) compared with those with FSIQ≤79 (89%; P=0.004). Relative weaknesses in processing speed were associated with educational support (83% vs. 52%, P=0.018) as well as behavioral aspects of executive functioning (Ps<0.05). Despite universal eligibility for a 504 Plan, 42% of youth with SCD in our sample did not have educational support. Significant deficits in intellectual functioning, processing speed, and parent-observed executive functioning are associated with having a plan, but children with subtle deficits seem less likely to be identified for educational support.

American Society of Hematology 2020 guidelines for sickle cell disease: prevention, diagnosis, and treatment of cerebrovascular disease in children and adults

BACKGROUND

Central nervous system (CNS) complications are among the most common, devastating sequelae of sickle cell disease (SCD) occurring throughout the lifespan.

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology are intended to support the SCD community in decisions about prevention, diagnosis, and treatment of the most common neurological morbidities in SCD.

METHODS

The Mayo Evidence-Based Practice Research Program supported the guideline development process, including updating or performing systematic evidence reviews. The panel used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, including GRADE evidence-to-decision frameworks, to assess evidence and make recommendations.

RESULTS

The panel placed a higher value on maintaining cognitive function than on being alive with significantly less than baseline cognitive function. The panel developed 19 recommendations with evidence-based strategies to prevent, diagnose, and treat CNS complications of SCD in low-middle- and high-income settings.

CONCLUSIONS

Three of 19 recommendations immediately impact clinical care. These recommendations include: use of transcranial Doppler ultrasound screening and hydroxyurea for primary stroke prevention in children with hemoglobin SS (HbSS) and hemoglobin Sβ0 (HbSβ0) thalassemia living in low-middle-income settings; surveillance for developmental delay, cognitive impairments, and neurodevelopmental disorders in children; and use of magnetic resonance imaging of the brain without sedation to detect silent cerebral infarcts at least once in early-school-age children and once in adults with HbSS or HbSβ0 thalassemia. Individuals with SCD, their family members, and clinicians should become aware of and implement these recommendations to reduce the burden of CNS complications in children and adults with SCD.

Nocturnal hypertension associated with stroke and silent cerebral infarcts in children with sickle cell disease

BACKGROUND

Strokes and silent cerebral infarcts (SCIs) lead to significant morbidity and mortality in children with sickle cell disease (SCD). Higher systolic blood pressures increase risk for stroke and SCIs; however, patients with SCD often have lower clinic blood pressures than the general population. Twenty-four-hour ambulatory blood pressure monitoring (ABPM) allows for more robust examination of blood pressures. This study evaluated associations between abnormal ABPM measurements with stroke and SCIs.

PROCEDURE

A cross-sectional study was performed. Children with SCD completed 24-hour ABPMs. Children with a documented magnetic resonance imaging (MRI) brain within a year of the ABPM were included in the analysis. Bivariate analyses were performed to identify associations between ABPM parameters with cerebrovascular outcomes.

RESULTS

Forty-two children with a median age of 13 years (10, 17) were included in the analysis. Seven (17%) had history of stroke and seven (17%) had SCIs. Nocturnal hypertension, elucidated via 24-hour ABPM, was noted in 25% of subjects. The presence of nocturnal hypertension was significantly higher in the SCI/stroke group (55% vs 12%, P = .01). Sensitivity analyses were performed during which stroke patients were removed from analysis. Nocturnal hypertension remained significantly associated with the presence of SCIs (P = .006).

CONCLUSIONS

This study reveals an association between nocturnal hypertension and a higher prevalence of SCI and stroke in children with SCD. Larger, prospective studies are needed to confirm these findings and evaluate the contributory nature of blood pressure abnormalities to cerebrovascular events in children with SCD.