Assessment of Executive Functions in Preschool Children With Sickle Cell Anemia.

OBJECTIVES: Children with sickle cell anemia (SCA) are commonly reported to experience executive dysfunction. However, the development of executive function (EF) in preschool-age children without stroke in this patient population has not been investigated so it is unclear when and how these deficits emerge. METHODS: This case-control study examines the feasibility of assessing the early development of executive functioning in 22 preschool children years with SCA in the domains of processing speed, working memory, attention, inhibitory control, and cognitive flexibility, as well as everyday function, in comparison to matched control children. RESULTS: A pattern of potential deficits in early emerging executive skills was observed in the domains of inhibitory control and cognitive flexibility. Parents reported no differences for everyday EF and no significant differences were observed for working memory and processing speed. CONCLUSIONS: Results suggest that deficits in everyday executive difficulties, working memory, and processing speed, as commonly reported for older children with SCA, may not yet have emerged at this early developmental stage, despite specific deficits in cognitive flexibility and inhibitory control on behavioral measures. The feasibility of using available executive measures with preschool age children to characterize the development of early EF skills is discussed. (JINS, 2018, 24, 949-954).

Altered Neurophysiological Processing of Auditory Attention in Preschool Children With Sickle Cell Disease.

Objective: Sickle cell disease (SCD) is a genetic red blood cell disorder that often leads to stroke and executive dysfunction in school-age children and adults. This study aimed to characterize the development of the neural correlates of selective attention, an early component of executive function, in preschool children with SCD. Methods: Auditory event-related potentials (ERPs) were recorded while children attended to a story stream in one ear and ignored a second story in the other ear interchangeably. In total, 12 patients (mean age = 5.5, 7 males) and 22 typically developing children (mean age = 4.4, 10 males) were included in the final analyses. Results: By 100 ms, more positive ERP amplitudes were observed for attended relative to unattended stimuli in typically developing children but not those with SCD, suggesting deficits in the ability to focus attention. Reduced attention effects were associated with lower performance intellectual quotient. Conclusion: There are deficits in early attention modulation in young children with SCD.

Controlled trial of transfusions for silent cerebral infarcts in sickle cell anemia.

BACKGROUND: Silent cerebral infarcts are the most common neurologic injury in children with sickle cell anemia and are associated with the recurrence of an infarct (stroke or silent cerebral infarct). We tested the hypothesis that the incidence of the recurrence of an infarct would be lower among children who underwent regular blood-transfusion therapy than among those who received standard care. METHODS: In this randomized, single-blind clinical trial, we randomly assigned children with sickle cell anemia to receive regular blood transfusions (transfusion group) or standard care (observation group). Participants were between 5 and 15 years of age, with no history of stroke and with one or more silent cerebral infarcts on magnetic resonance imaging and a neurologic examination showing no abnormalities corresponding to these lesions. The primary end point was the recurrence of an infarct, defined as a stroke or a new or enlarged silent cerebral infarct. RESULTS: A total of 196 children (mean age, 10 years) were randomly assigned to the observation or transfusion group and were followed for a median of 3 years. In the transfusion group, 6 of 99 children (6%) had an end-point event (1 had a stroke, and 5 had new or enlarged silent cerebral infarcts). In the observation group, 14 of 97 children (14%) had an end-point event (7 had strokes, and 7 had new or enlarged silent cerebral infarcts). The incidence of the primary end point in the transfusion and observation groups was 2.0 and 4.8 events, respectively, per 100 years at risk, corresponding to an incidence rate ratio of 0.41 (95% confidence interval, 0.12 to 0.99; P=0.04). CONCLUSIONS: Regular blood-transfusion therapy significantly reduced the incidence of the recurrence of cerebral infarct in children with sickle cell anemia. (Funded by the National Institute of Neurological Disorders and Stroke and others; Silent Cerebral Infarct Multi-Center Clinical Trial ClinicalTrials.gov number, NCT00072761, and Current Controlled Trials number, ISRCTN52713285.).

Parent reported sleep problems in preschool children with sickle cell anemia and controls in East London.

Snoring and poor sleep may affect cognition, particularly in young children with chronic conditions. Parents of London preschoolers with sickle cell anemia (SCA; n = 22), matched controls (n = 24), and unselected typically developing (n = 142) preschoolers completed sleep questionnaires. Preschoolers with SCA had significantly more sleep problems when compared to matched controls and the larger population. Snoring occurred at least one to two nights a week for 79% of the SCA group. This is compared with 25% of matched controls and 33% of larger population. Randomized controlled trials to improve sleep in young children with SCA already at-risk for cognitive dysfunction should be considered.

Associated risk factors for silent cerebral infarcts in sickle cell anemia: low baseline hemoglobin, sex, and relative high systolic blood pressure.

The most common form of neurologic injury in sickle cell anemia (SCA) is silent cerebral infarction (SCI). In the Silent Cerebral Infarct Multi-Center Clinical Trial, we sought to identify risk factors associated with SCI. In this cross-sectional study, we evaluated the clinical history and baseline laboratory values and performed magnetic resonance imaging of the brain in participants with SCA (HbSS or HbSß° thalassemia) between the ages of 5 and 15 years with no history of overt stroke or seizures. Neuroradiology and neurology committees adjudicated the presence of SCI. SCIs were diagnosed in 30.8% (251 of 814) participants who completed all evaluations and had valid data on all prespecified demographic and clinical covariates. The mean age of the participants was 9.1 years, with 413 males (50.7%). In a multivariable logistic regression analysis, lower baseline hemoglobin concentration (P < .001), higher baseline systolic blood pressure (P = .018), and male sex (P = .030) were statistically significantly associated with an increased risk of an SCI. Hemoglobin concentration and systolic blood pressure are risk factors for SCI in children with SCA and may be therapeutic targets for decreasing the risk of SCI. This study is registered at www.clinicaltrials.gov as #NCT00072761.

Cervical carotid artery disease in sickle cell anemia: clinical and radiological features.

Cervical internal carotid artery (cICA) occlusion is a recognized cause of acute ischemic stroke (AIS) in sickle cell disease (SCD), but the associated clinical and radiologic features are not well described. We reviewed data on cervical magnetic resonance angiography (cMRA) performed prospectively in 67 patients (55 children) for indications including transcranial Doppler (TCD) abnormalities, AIS, or previous AIS. cICA lesions were seen in 10 (15%) patients, including 4 of 7 patients presenting with AIS, and appear to have been missed on first presentation in 4 of 10 patients with previous AIS. Radiologic features in 7 patients were consistent with dissection. In 2 patients, there was strong clinical and radiologic evidence for thromboembolic AIS, and this was also considered possible in 4 other patients. Three of the 4 AIS patients were anticoagulated acutely, and the nontreated patient had recurrent, probably thromboembolic, AIS. TCD findings were variable, but in 4 patients there were high velocities in the cerebral vessels contralateral to the cICA stenosis. We suggest that all patients with AIS should have cMRA during acute evaluation to identify cICA occlusions that may require anticoagulation. Routine screening of children with SCD should also include evaluation of neck vessels by carotid Doppler followed by cMRA if a cervical vascular lesion is suspected.

Temperament in preschool children with sickle cell anaemia.

AIMS: Few studies have investigated the potential impact of sickle cell anaemia (SCA) on temperament. The aim of the current study was to investigate temperament in preschool children with SCA and to establish the reliability of the Children's Behaviour Questionnaire (CBQ) in this population. METHODS: The CBQ, a parent-report measure of temperament, was completed by parents of 21 preschool children with SCA and a control group of parents of typically developing children, matched for age, ethnicity and socioeconomic status. RESULTS: A significant difference between groups was identified for the dimension of negative affectivity only, with specific differences observed in the discomfort subdomain. Patients with a greater number of hospital admissions in the previous year were reported to have higher levels of discomfort. CONCLUSIONS: Preschool children with SCA are reported to have higher rates of negative affectivity, particularly discomfort. Future research is required to investigate the potential influence of dysregulated negative emotions and discomfort on disease management and quality of life throughout childhood.

The Role of Family Functioning in the Development of Executive Functions in Preschool Children with Sickle Cell Anemia.

Executive functions are compromised in children with sickle cell anemia. There is limited research on the development of executive functions in preschool children with sickle cell anemia and the factors that contribute to executive dysfunction. We looked at the relation between biomedical and environmental factors, including family functioning and socioeconomic status, and executive functions in 22 preschool children with sickle cell anemia. We found that family functioning was the strongest predictor of executive outcomes in young children with sickle cell anemia with no evidence for an influence of disease severity at this early stage.

Precursors of executive function in infants with sickle cell anemia.

Executive dysfunction occurs in sickle cell anemia, but there are few early data. Infants with sickle cell anemia (n = 14) and controls (n = 14) performed the "A-not-B" and Object Retrieval search tasks, measuring precursors of executive function at 9 and 12 months. Significant group differences were not found. However, for the A-not-B task, 7 of 11 sickle cell anemia infants scored in the lower 2 performance categories at 9 months, but only 1 at 12 months (P = .024); controls obtained scores at 12 months that were statistically comparable to the scores they had already obtained at 9 months. On the Object Retrieval task, 9- and 12-month controls showed comparable scores, whereas infants with sickle cell anemia continued to improve (P = .027); at 9 months, those with lower hemoglobin oxygen saturation passed fewer trials (R s = 0.670, P = .024) and took longer to obtain the toy (R s = -0.664, P = .013). Subtle delays in acquiring developmental skills may underlie abnormal executive function in childhood.

Detection and partial characterization of simian immunodeficiency virus SIVsm strains from bush meat samples from rural Sierra Leone.

Human immunodeficiency virus type 2 (HIV-2) originated from simian immunodeficiency viruses (SIVs) that naturally infect sooty mangabeys (SMs; Cercocebus atys). In order to further investigate the relationship between HIV-2 and SIVsm, the SIV specific to the SM, we characterized seven new SIVsm strains from SMs sold in Sierra Leone markets as bush meat. The gag, pol, and env sequences showed that, while the viruses of all seven SMs belonged to the SIVsm-HIV-2 lineage, they were highly divergent viruses, in spite of the fact that most of the samples originated from the same geographical region. They clustered in three lineages, two of which have been previously reported. Two of the new SIVsm strains clustered differently in gag and env phylogenetic trees, suggesting SIVsm recombination that had occurred in the past. In spite of the fact that our study doubles the number of known SIVsm strains from wild SMs, none of the simian strains were close to the groups in which HIV-2 was epidemic (groups A and B).

High levels of SIVmnd-1 replication in chronically infected Mandrillus sphinx.

Viral loads were investigated in SIVmnd-1 chronically infected mandrills and the results were compared with those previously observed in other nonpathogenic natural SIV infections. Four naturally and 11 experimentally SIVmnd-1-infected mandrills from a semi-free-ranging colony were studied during the chronic phase of infection. Four SIVmnd-1-infected wild mandrills were also included for comparison. Twelve uninfected mandrills were used as controls. Viral loads in all chronically infected mandrills ranged from 10(5) to 9 x 10(5) copies/ml and antibody titers ranged from 200 to 14,400 and 200 to 12,800 for anti-V3 and anti-gp36, respectively. There were no differences between groups of wild and captive mandrills. Both parameters were stable during the follow-up, and no clinical signs of immune suppression were observed. Chronic SIVmnd-1-infected mandrills presented slight increases in CD20+ and CD28+/CD8+ cell counts, and a slight decrease in CD4+/CD3+ cell counts. A slight CD4+/CD3+ cell depletion was also observed in old uninfected controls. Similar to other nonpathogenic models of lentiviral infection, these results show a persistent high level of SIVmnd-1 replication during chronic infection of mandrills, with minimal effects on T cell subpopulations.