Detection and assessment of stroke in patients with sickle cell disease: neuropsychological functioning and magnetic resonance imaging.

Sickle cell disease (SCD) is associated with increased risk of stroke and cognitive impairment. This study describes a retrospective review of 65 patients who underwent routine neuropsychological testing and MRI during treatment at a comprehensive sickle cell center. It was hypothesized that (1) children with no evidence of CVA would perform lower than expected on cognitive tasks compared to population-based normative data, (2) children with strokes and children with silent infarcts would perform lower on cognitive tasks and motor skills as compared to patients with no evidence of CVA, and (3) children with evidence of silent infarcts would perform better than children with known overt strokes. This final hypothesis has not been studied previously, as children with known overt stroke and silent infarct were grouped together. Sixty-five children with SCD who were sent for routine neuropsychological testing and brain MRI were identified via retrospective chart review. Patients had been administered neuropsychological tests to assess cognitive, executive and motor function. Brain MRI was obtained from each patient and was analyzed for evidence of cerebrovascular accident (CVA). Based on MRI analysis, 27% of patients with SCD had experienced a stroke and 13% a silent infarct. The majority (59%) of patients diagnosed with stroke or infarct sustained cortical damage to the frontal lobe. Patients with SCD and no evidence of CVA functioned normally on tests of cognitive ability and achievement, but patients with CVA displayed impairments in cognitive function and comparatively lower scores on verbal and performance scales. Neuropsychological testing can identify impairments in patients with SCD with no known cerebrovascular accident. Investigations of neurocognitive functioning will help characterize patterns of deficits and can inform the ability to implement comprehensive care strategies for patients with SCD and cognitive impairment.

Principles and practices of neurodevelopmental assessment in children: lessons learned from the Centers for Children's Environmental Health and Disease Prevention Research.

Principles and practices of pediatric neurotoxicology are reviewed here with the purpose of guiding the design and execution of the planned National Children's Study. The developing human central nervous system is the target organ most vulnerable to environmental chemicals. An investigation of the effects of environmental exposures on child development is a complex endeavor that requires consideration of numerous critical factors pertinent to a study's concept, design, and execution. These include the timing of neurodevelopmental assessment, matters of biologic plausibility, site, child and population factors, data quality assurance and control, the selection of appropriate domains and measures of neurobehavior, and data safety and monitoring. Here we summarize instruments for the assessment of the neonate, infant, and child that are being employed in the Centers for Children's Environmental Health and Disease Prevention Research, sponsored by the National Institute of Environmental Health Sciences and the U.S. Environmental Protection Agency, discuss neural and neurobiologic measures of development, and consider the promises of gene-environment studies. The vulnerability of the human central nervous system to environmental chemicals has been well established, but the contribution these exposures may make to problems such as attention deficit disorder, conduct problems, pervasive developmental disorder, or autism spectrum disorder remain uncertain. Large-scale studies such as the National Children's Study may provide some important clues. The human neurodevelopmental phenotype will be most clearly represented in models that include environmental chemical exposures, the social milieu, and complex human genetic characteristics that we are just beginning to understand.

Autosomal recessive frontotemporal pachygyria.

Pachygyria is a cortical malformation that results from the abnormal migration of neurons. Regions of the brain with pachygyria have an abnormally thick cortex that lacks normal folding and has deficient layering. We describe three siblings, born to nonconsanguineous Mexican parents, who have bilateral frontotemporal pachygyria without polymicrogyria. The pachygyria is accompanied by moderate mental retardation, esotropia, and either hypertelorism or telecanthus. They are otherwise morphologically normal and do not have microcephaly. Two experienced a single seizure in infancy. The characteristic phenotype present in this family suggests a new genetic syndrome that is likely inherited as an autosomal recessive trait.