Biomedical subjects

Stephen R Hooper

Publications and source records attributed to Stephen R Hooper.

18 recordsLinked to original sources

PubMed2006

The central nervous system in childhood chronic kidney disease.

Neurodevelopmental deficits in pediatric and adult survivors of childhood onset chronic kidney disease (CKD) have been documented for many years. This paper reviews the available literature on central nervous system involvement incurred in childhood CKD. The studies reviewed include recent work in neuroimaging, electrophysiology, and neuropsychology, along with commentary on school functioning and long-term outcomes. The paper concludes with suggestions for monitoring the neurodevelopmental status and pursuing appropriate early interventions for children with CKD.

Achievement↗

PubMed2006

Hershey Medical Center Technical Workshop Report: optimizing the design and interpretation of epidemiologic studies for assessing neurodevelopmental effects from in utero chemical exposure.

Neurodevelopmental disabilities affect 3-8% of the 4 million babies born each year in the U.S. alone, with known etiology for less than 25% of those disabilities. Numerous investigations have sought to determine the role of environmental exposures in the etiology of a variety of human neurodevelopmental disorders (e.g., learning disabilities, attention deficit-hyperactivity disorder, intellectual disabilities) that are manifested in childhood, adolescence, and young adulthood. A comprehensive critical examination and discussion of the various methodologies commonly used in investigations is needed. The Hershey Medical Center Technical Workshop: Optimizing the design and interpretation of epidemiologic studies for assessing neurodevelopmental effects from in utero chemical exposure provided such a forum for examining these methodologies. The objective of the Workshop was to develop scientific consensus on the key principles and considerations for optimizing the design and interpretation of epidemiologic studies of in utero exposure to environmental chemicals and subsequent neurodevelopmental effects. (The Panel recognized that the nervous system develops post-natally and that critical periods of exposure can span several developmental life stages.) Discussions from the Workshop Panel generated 17 summary points representing key tenets of work in this field. These points stressed the importance of: a well-defined, biologically plausible hypothesis as the foundation of in utero studies for assessing neurodevelopmental outcomes; understanding of the exposure to the environmental chemical(s) of interest, underlying mechanisms of toxicity, and anticipated outcomes; the use of a prospective, longitudinal cohort design that, when possible, runs for periods of 2-5 years, and possibly even longer, in an effort to assess functions at key developmental epochs; measuring potentially confounding variables at regular, fixed time intervals; including measures of specific cognitive and social-emotional domains along with non-cognitive competence in young children, as well as comprehensive measures of health; consistency of research design protocols across studies (i.e., tests, covariates, and analysis styles) in an effort to improve interstudy comparisons; emphasis on design features that minimize introduction of systematic error at all stages of investigation: participant selection, data collection and analysis, and interpretation of results; these would include (but not be limited to) reducing selection bias, using double-blind designs, and avoiding post hoc formulation of hypotheses; a priori data analysis strategies tied to hypotheses and the overall research design, particularly for methods used to characterize and address confounders in any neurodevelopmental study; actual quantitative measurements of exposure, even if indirect, rather than methods based on subject recall; careful examination of standard test batteries to ensure that the battery is tailored to the age group as well as what is known about the specific neurotoxic effects on the developing nervous system; establishment of a system for neurodevelopmental surveillance for tracking the outcomes from in utero exposure across early developmental time periods to determine whether central nervous system injuries may be lying silent until developmentally challenged; ongoing exploration of computerized measures that are culturally and linguistically sensitive, and span the age range from birth into the adolescent years; routine incorporation of narrative in manuscripts concerning the possibility of spurious (i.e., false positive and false negative) test results in all research reportage (this can be facilitated by detailed, transparent reporting of design, covariates, and analyses so that others can attempt to replicate the study); forthright, disciplined, and intellectually honest treatment of the extent to which results of any study are conclusive--that is, how generalizable the results of the study are in terms of the implications for the individual study participants, the community studied, and human health overall; confinement of reporting to the actual research questions, how they were tested, and what the study found, and avoiding, or at least keeping to a minimum, any opinions or speculation concerning public health implications; education of clinicians and policymakers to critically read scientific reports, and to interpret study findings and conclusions appropriately; and recognition by investigators of their ethical duty to report negative as well as positive findings, and the importance of neither minimizing nor exaggerating these findings.

Biomedical Research↗

PubMed2006

Visuospatial executive function in Turner syndrome: functional MRI and neurocognitive findings.

Turner syndrome is a genetic disorder that results from an abnormal or missing X chromosome in females and is typically associated with impairments in visuospatial, but not verbal, information processing. These visuospatial processing impairments may be exacerbated with increased task demands, such as those engaged during working memory (WM). While previous studies have examined spatial WM function in Turner syndrome, none have directly compared the neural correlates of spatial and verbal WM processes across the encoding, maintenance and retrieval phases. We employed both neurocognitive assessments and functional MRI (fMRI) to examine the neural circuitry underlying both verbal and visuospatial WM functions in individuals with Turner syndrome and normal controls. We furthermore examined the vulnerability of task-related fMRI activation to distracters presented during WM maintenance. Fifteen healthy female volunteers and eight individuals with Turner syndrome performed a delayed-response WM task during fMRI scanning. Neurocognitive tests revealed impaired performance across both verbal and spatial domains in Turner syndrome, with greater impairment on tasks with WM demands. Frontoparietal regions in controls showed significantly sustained levels of activation during visuospatial WM. This sustained activation was significantly reduced in the group with Turner syndrome. Domain-specific activation of temporal regions, in contrast, did not differ between the two groups. Sensory distraction during the WM maintenance phase did not differentially alter frontoparietal activation between the two groups. The results reveal impaired frontoparietal circuitry recruitment during visuospatial executive processing in Turner syndrome, suggesting a significant role for the X chromosome in the development of these pathways.

Adolescent↗

PubMed2006

Neurocognitive outcomes in children with chronic kidney disease: Current findings and contemporary endeavors.

Given the rise in chronic kidney disease (CKD) in both children and adults, CKD has recently been targeted as a public health priority. Childhood onset kidney disease is generally a noncurable and progressive condition that leads to kidney failure by early adulthood. Fortunately, improved identification of kidney problems allows for early intervention, which is thought to slow progression toward end-stage renal disease. In addition, medical interventions for pediatric end-stage renal disease have also improved, allowing children to take advantage of lifesaving renal replacement treatments such as dialysis and kidney transplantation. In spite of improvements in identification and treatment, CKD causes both direct and indirect insults to a variety of organ systems. This paper reviews recently published studies pertaining to the neurocognitive and psychosocial impact of CKD on children of various ages and at various stages of kidney failure. Specific attention is focused on summarizing peer reviewed research that describes associations between kidney functioning and cognitive functioning, language acquisition, visual spatial abilities, memory, and executive functioning. In addition, peer reviewed research describing psychosocial outcomes associated with CKD related to academic achievement, social-behavioral functioning, and quality of life are summarized. The authors also identified disease-specific factors that likely mediate neurocognitive outcomes (e.g., anemia, hypertension, cardiovascular) and endorse the importance of continued interdisciplinary research collaborations that will provide a better understanding of the mechanisms responsible for improved neurocognitive functioning after transplantation. The authors conclude this review by describing a multicenter, prospective, longitudinal, National Institutes of Health funded study that is currently examining the developmental outcomes of children with mild to moderate CKD. The authors speculate that the Chronic Kidney Disease in Children Prospective Cohort Study (CKiD) findings will provide additional evidence-based guidance for clinicians and researchers working with children and adolescents with deteriorating kidney function to improve medical and developmental outcomes.

Adolescent↗

PubMed2006

Neuropsychological characteristics of school-age children with high-functioning autism: performance on the NEPSY.

Utilizing standardization and validation data from the NEPSY, this study presents a reanalysis of the High-Functioning Autism (HFA) versus Typical samples using IQ as a covariate. The reanalysis in the present paper should prove important to clinicians and researchers by (1) determining if the original findings can be replicated for the HFA sample when controlling for IQ, and (2) providing neuropsychological description for children with HFA versus Typical children across the NEPSY variables. The sample included 23 children with HFA who ranged in age from 5 years 5 months to 12 years 11 months (Mean = 9.59 years). The HFA Group comprised 19 males, 22 Caucasians, and was 87% right handed. All of the parents had between 12 to 15 years of education. A Typical Group was selected from the standardization sample of the NEPSY and matched on the variables of chronological age, race, gender, parental education, and region of the country. A MANCOVA revealed significant group differences on 8 of the 14 core subtests of the NEPSY, with the HFA Group performing lower than the Typical Group. While these findings significantly overlapped with those from the original validation study, significant group differences also were uncovered for the subtests of Phonological Processing, Auditory Attention and Response Set, and Speeded Naming; Comprehension of Instructions and Narrative Memory were no longer significant after controlling for IQ. When the groups were compared with respect to the number of cases falling below the 10th percentile, the HFA Group showed a higher rate of occurrence on each subtest, but only significantly so on the Arrows Subtest. These findings provide additional support for the phenotypic neurocognitive presentation of individuals with HFA, and they suggest that the NEPSY can contribute to the neuropsychological description of children with HFA.

Analysis of Variance↗

PubMed2006

Memory and executive functions in pediatric chronic kidney disease.

This study examined the memory and executive functioning of children and adolescents with chronic kidney disease (CKD). The sample included 20 children and adolescents with CKD ranging in age from 7.50 to 19.04 years (M = 13.41, SD = 3.20). Intellectual function for the group was within the low average to average range (M = 89.32, SD = 14.80). Of the participants with CKD, 12 were receiving maintenance dialysis therapy at the time of testing and 8 were managed with conservative therapy. Healthy controls were used as a comparison group (n = 18). This group ranged in age from 7.47 to 18.37 years (M = 12.93, SD = 2.90). Intellectual function was within the average range (M = 112.18, SD = 13.14). All subjects received a comprehensive battery of memory and executive function tasks as part of a larger neuropsychological evaluation. Preliminary examinations of the data revealed a significant difference between the groups in IQ, with the typical group being significantly higher than the CKD group. A multivariate analysis controlling for chronological age revealed significant group differences, with specific differences being noted in all of the memory functions, and the Initiation and Sustaining executive function domains. In all instances the CKD group performed lower than the typical group. The CKD group was particularly deficient in their initiation behaviors within the executive function domain. The groups did not differ on Set-Shifting or Inhibition. These findings remained present even when IQ and chronological age were controlled in the analyses, suggesting the possibility of specific encroachment of renal disease on memory and executive functions beyond the generalized effects of lower IQ. This study represents one of the most extensive examinations of memory and executive functions that has been conducted to date on children and adolescents with CKD. While pervasive dysfunction was not apparent in the children with CKD, they clearly appeared to be at risk for lower IQ as well as inefficiencies in key neurocognitive domains.

Adolescent↗

PubMed2006

The relationship of otitis media in early childhood to attention dimensions during the early elementary school years.

This study examined the impact of otitis media with effusion (OME) and associated hearing loss between 6 and 48 months of age on attention dimensions (i.e., selective/focus, sustained) during the elementary school years. A prospective cohort design in which 74 African American infants were recruited between ages 6 and 12 months. Ear examinations were done repeatedly using both otoscopy and tympanometry, and hearing was assessed using standard audiometric procedures between 6 and 48 months. Multiple measures of attention (i.e., direct assessment, behavioral observations, parent/teacher ratings) were administered from kindergarten through second grade to assess two theoretical dimensions of attention: selective/focused and sustained. The home environment was assessed annually. Results indicated that neither early childhood OME nor hearing loss showed significant correlations with any of the longitudinal or cross-sectional measures of selective/focused attention and sustained attention. In contrast, children with mothers who had fewer years of education and who lived in less responsive and supportive home environments scored higher on both parent and teacher ratings of sustained attention (i.e., hyperactivity) through the second grade of elementary school. For NEPSY Auditory Attention in second grade, a significant interaction between the Home Observation for Measurement of the Environment and hearing loss was uncovered. This interaction showed that children with hearing loss from poor home environments experienced greater difficulties on the NEPSY Auditory Attention task than those with hearing loss from good home environments. These findings do not support a direct linkage of a history of OME and associated hearing loss to difficulties in selective/focused attention or sustained attention in early elementary school children. Relationships between sociodemographic variables and attention-related functions appear stronger and should be considered as mediators in any examination of the linkages between early OME and subsequent attention functions.

Attention↗

PubMed2006

Aptitude-treatment interactions revisited: effect of metacognitive intervention on subtypes of written expression in elementary school students.

We examined the effectiveness of a metacognitive intervention for written language performance, based on the Hayes model of written expression, for 73 fourth-grade (n = 38) and fifth-grade (n = 35) students. The intervention consisted of twenty 45-min writing lessons designed to improve their awareness of writing as a problem-solving process. Each of the lessons addressed some aspect of planning, translating, and reflecting on written products; their self-regulation of these processes; and actual writing practice. All instruction was conducted in intact classrooms. Prior to the intervention, all students received a battery of neurocognitive tests measuring executive functions, attention, and language. In addition, preintervention writing samples were obtained and analyzed holistically and for errors in syntax, semantics, and spelling. Following the intervention, the writing tasks were readministered and cluster analysis of the neurocognitive data was conducted. Cluster analytic procedures yielded 7 reliable clusters: 4 normal variants, 1 Problem Solving weakness, 1 Problem Solving Language weaknesses, and 1 Problem Solving strength. The response to the single treatment by these various subtypes revealed positive but modest findings. Significant group differences were noted for improvement in syntax errors and spelling, with only spelling showing differential improvement for the Problem Solving Language subtype. In addition, there was a marginally significant group effect for holistic ratings. These findings provide initial evidence that Writing Aptitude (subtype) x Single Treatment interactions exist in writing, but further research is needed with other classification schemes and interventions.

Aptitude↗

PubMed2006

Subtypes of written expression in elementary school children: a linguistic-based model.

The purpose of this study was to provide a reliable and valid classification scheme for written expression that captured the linguistic variability present in a typical elementary school sample. This empirically derived classification model was based on the following linguistic-based writing skills: (a) understandability of discourse, (b) grammar, (c) semantics, (d) spelling, and (e) reading comprehension. The sample included 257 fourth-grade (n = 142) and fifth-grade (n = 115) students (46.3% boys, 79.4% White, age range = 8;3-11;7 years; M = 10.10). All of the students were receiving their writing instruction in the regular education setting, with approximately one third receiving some type of educational assistance. The sample fell in the middle socioeconomic stratum. Cluster analytic techniques derived different possible solutions. Results of a series of internal validity studies provided strong evidence that the six-cluster solution was both stable and interpretable, with subtypes reflecting normal as well as writing disability variants. Further, the writing disability subtypes ranged from global impairment to more specific linguistic impediments. Based on their characteristics, the clusters were named (a) Average Writers (n = 102), (b) Low Semantics (n = 31), (c) Low Grammar (n = 18), (d) Expert Writers (n = 33), (e) Low Spelling-Reading (n = 13), and (f) Poor Text Quality (n = 60). Subtypes differed on the percentages of children in selected subtypes manifesting specific writing deficits as well as on selected aspects of measures of metacognition, self-efficacy, and self-regulation of the writing process. Results provide researchers with a foundation to further investigate the underlying neurolinguistic and neurocognitive processes that may strengthen or undermine students' ability to produce a quality written product and to design and implement intervention techniques to address the various subtype patterns inherent in a regular elementary school classroom.

Analysis of Variance↗

PubMed2004

The nervous system and chronic kidney disease in children.

This paper provides a review of the literature on the nervous system involvement incurred by children and adolescents with chronic kidney disease (CKD), with a particular focus on neuropsychological functioning. In addition to an historical overview of earlier literature, published studies from the past 14 years that address both central and peripheral nervous system function in children with CKD are reviewed (1990-2003). These studies span work in neuroimaging, electrophysiology, and neuropsychology. A key focus for this review is on variables that might affect neurodevelopmental status in these children. The paper concludes with suggestions for achieving progress in the understanding of this complication of kidney disease in children.

Adolescent↗

PubMed2004

Neurometabolic functioning and neuropsychological correlates in children with ADHD-H: preliminary findings.

Proton magnetic resonance spectroscopy (MRS) and neuropsychological testing were conducted on 8 children with attention-deficit/hyperactivity disorder (ADHD-H), with no learning disabilities or comorbidities and 8 controls. Magnetic resonance spectroscopy revealed increased Glutamate/Glutamine in both frontal areas, and increased N-acetyl aspartate and Choline in the right frontal area of the ADHD-H subjects. Neuropsychological testing revealed few within- and between-group differences. Findings related to frontal lobe dysfunction in ADHD-H subjects were noted. N-acetylasparte/creatine (NAA/Creatine) in the right frontal region, and myoinositol/creatine (Myo inositol/Creatine) in the right and left frontal regions appear to be highly associated with the regulation of sensorimotor, language, and memory and learning functioning in children with ADHD-H.

Aspartic Acid↗

PubMed2004

Caregiver reports of common symptoms in children following a traumatic brain injury.

This study describes the common symptoms in children and adolescents following a traumatic brain injury (TBI) as reported by their primary caregivers. Utilizing data from a large-scale state demonstration project, 681 children who had sustained a TBI were ascertained from both Hospital Emergency Departments (n = 409) and Pediatric Inpatient settings (n = 272). The sample ranged in age from infancy to 18 years, was largely male (59.7%), and had equal numbers of Caucasian and minority patients. Most of the participants experienced a mild TBI (83%), with about 5.1% being moderate and 12% severe. Caregivers described the presence of current symptoms (neurological, neurocognitive, behavioral, school problems) using a series of dichotomous questions regarding their child via a structured telephone interview at 1, 4, and 10 months post-injury. Inpatient children were described as manifesting more symptoms at each of the follow-up time points than their ED counterparts. At 1 month inpatients were described as having more symptoms across all 4 domains. At 4 and 10 months, the inpatients were described as having more neurocognitive symptoms and as not returning to school on a full-time basis, with behavior problems approaching significance at the 10-month point. A large number of individuals from both groups also reported persistent symptoms 10 months post-injury including headaches, attention and memory problems, low frustration tolerance, sleep problems, personality changes, and new school problems. Practical implications of these findings for the ongoing management of these children are discussed.

Adolescent↗

PubMed2002

Problem behavior in boys with fragile X syndrome.

This study examines problem behavior over time in 59 boys with fragile X syndrome (FXS), aged 4-12 years, using the Child Behavior Checklist (CBCL). Approximately 49% of the boys scored within the borderline or clinical range on total problem behavior, while 56-57% scored in the borderline or clinical range on the attention and thought problems subscales, and 26% scored in this range on the social problems subscale. With a mean of 2.5 assessments per child, behavior problems were stable during the 3-year period of study. Total problem behavior was higher for children who displayed autistic behavior, were rated as low in adaptability, had mothers with higher maternal education levels, and were on medication. Mothers with more education also rated their children as having more attention, thought, and total problems. Children taking medication differed from boys who were not taking medication on social problems, but not on attention and thought problems. Low adaptability and more autistic characteristics predicted thought problems.

Adaptation, Psychological↗

PubMed2002

Morphometric and neuropsychologic studies in children with arachnoid cysts.

Temporal lobe arachnoid cysts are common findings during brain imaging. Debate exists regarding whether they result from temporal lobe agenesis or are a malformation of the arachnoid matter. We measured temporal lobe volumes in five children with left middle cranial fossa arachnoid cysts using morphometric analysis of magnetic resonance imaging scans. Three patients had neuropsychologic testing, and two patients had positron emission tomography scanning. All patients had significantly smaller left temporal lobes compared with the right side. On neuropsychologic testing two patients had cognitive deficits suggestive of left temporal lobe dysfunction. Temporal lobes adjacent to arachnoid cysts are smaller and less metabolically active when compared with the temporal regions on the opposite side. Patients with middle cranial fossa arachnoid cysts should undergo careful assessment of temporal lobe structure and function before any therapeutic intervention.

Adolescent↗

PubMed2002

Three-year course of learning disorders in special education students classified as behavioral disorder.

OBJECTIVE: To investigate the 3-year course of learning disorders (LDs) and academic achievement in a sample of students with psychiatric disorders who were newly classified by the special education category of behavioral disorder (BD). METHOD: The occurrence of four definitions for LD (both discrepancy and low achievement) based on the WISC-R and the Woodcock-Johnson Psychoeducational Battery was followed in 81 students with BD from the time of their enrollment in BD classes to their first reevaluation after 3 years. Odds ratios (ORs) were used to measure stability of LDs in these students. RESULTS: The prevalence of any LD was 64.2% at baseline and 61.7% at follow-up. Most of the 10 possible LD categories showed significant ORs, and the average OR was 21.9. At follow-up after 3 years, students both with and without LD at baseline had approximately the same achievement standard scores in reading and mathematics, but a significantly lower score for written language. Standard scores for the students without LD consistently were significantly higher than the scores for students with comorbid LD. CONCLUSION: LDs in this unique sample of students with psychiatric disorders remained common and generally stable over the first 3 years.

Adolescent↗

PubMedDate not supplied

The language of written language: an introduction to the special issue.

This special issue includes five articles dealing with selected aspects of writing disorders, crafted by key contributors to the literature on written language. Articles addressing definitional issues and diagnostic questions, assessment strategies, selected neurodevelopmental components of written expression, the manifestation of writing problems in children and young adults, direct intervention, training for elementary teachers in the early grades in the area of literacy, and brain-behavior linkages are presented. This introduction provides an overview of these articles tied to specific issues confronting the field of written language. Some thoughts and directions for the future are articulated.

Adult↗

PubMedDate not supplied

Executive functions in elementary school children with and without problems in written expression.

This study examined the executive functioning of 55 elementary school children with and without problems in written expression. Two groups reflecting children with and without significant writing problems were defined by an average primary trait rating across two separate narratives. The groups did not differ in terms of chronological age, ethnicity, gender, socioeconomic status, special education status, or presence of attention problems or receptive vocabulary capabilities; however, they did differ in reading decoding ability, and this variable was controlled for in all analyses. Dependent measures included tasks tapping an array of executive functions grouped conceptually in accordance with a model of executive functioning reflecting the following domains: initiate, sustain, set shifting, and inhibition/stopping. Analysis of covariance (ANCOVA) procedures revealed statistically significant group differences on the initiation and set shift domains, with the sustaining domain approaching significance. Children with writing problems performed more poorly in each of these domains, although the effect sizes were small. A multiple regression that employed these four factors and the reading decoding variable to predict the primary trait score from the written narratives revealed a statistically significant regression function; however, reading decoding contributed most of the unique variance to the writing outcome. These findings point out the importance of executive functions in the written language process for elementary school students, but highlight the need to examine other variables when studying elementary school-age children with written expression problems.

Child↗

PubMedDate not supplied

Sensory processing correlates of occupational performance in children with fragile X syndrome: preliminary findings.

OBJECTIVES: This preliminary study examined sensory processing and its relationship to occupational performance in children with fragile X syndrome (FXS) to guide research and evidence-based practice. METHOD: Fifteen school-aged boys with full-mutation FXS were assessed with three occupational performance measures (School Function Assessment, Vineland Adaptive Behavior Scales, play duration) and three sensory processing measures (Sensory Profile, Tactile Defensiveness and Discrimination Test-Revised, Sensory Approach-Avoidance Rating). Data were analyzed using partial correlation procedures. RESULTS: Several significant correlations were found, independent of effects of age and IQ. Avoidance of sensory experiences (internally controlled) was associated with lower levels of school participation, self-care, and play. Aversion to touch from externally controlled sources was associated with a trend toward greater independence in self-care--opposite of expectations. CONCLUSION: This study links sensory processing vulnerabilities with individual differences in occupational performance and supports a dynamic view of self-organizing systems. Children's uses of avoidant versus independent behaviors may reflect different self-regulatory or coping strategies that potentially mediate the relationship between sensory processing deficits and occupational behaviors and warrant further investigation.

Activities of Daily Living↗