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Lifespan outcomes of simultaneous versus sequential myelomeningocele repair and shunt placement or effects of repeated shunt revisions on specific domains of IQ or fine motor dexterity are largely unknown. The current study addressed these gaps in a large cohort of children and adults with spina bifida myelomeningocele (SBM).
Participants between 7 and 44 years of age with SBM and shunted hydrocephalus were recruited from international clinics at two time points. Each participant completed a standardized neuropsychological evaluation that included estimates of IQ and fine motor dexterity. Simultaneous versus sequential surgical repair and number of shunt revisions were examined in relation to long-term IQ and fine motor scores.
Simultaneous myelomeningocele repair and shunting were associated with more frequent shunt revisions, as well as to lower Full Scale and verbal IQ scores, controlling for number of shunt revisions. More shunt revisions across study time points were associated with higher nonverbal IQ (NVIQ) scores. No effects were observed on fine motor dexterity.
Findings indicate generally greater influence of surgery type over shunt revision history on outcomes in well-managed hydrocephalus. Findings supported apparent, domain-specific benefits of sequential compared to simultaneous surgery across the lifespan in SBM. Higher NVIQ scores with greater number of additional shunt revisions across surgery type supported positive outcomes with effective surgical management for hydrocephalus.
Objectives: Fluency is a major problem for individuals with neurodevelopmental disorders, including fluency deficits for academic skills. The aim of this study was to determine neurocognitive predictors of academic fluency within and across domains of reading, writing, and math, in children and adults, with and without spina bifida. In addition to group differences, we expected some neurocognitive predictors (reaction time, inattention) to have similar effects for each academic fluency outcome, and others (dexterity, vocabulary, nonverbal reasoning) to have differential effects across outcomes. Methods: Neurocognitive predictors were reaction time, inattention, dexterity, vocabulary, and nonverbal reasoning; other factors included group (individuals with spina bifida, n=180; and without, n=81), age, and demographic and untimed academic content skill covariates. Univariate and multivariate regressions evaluated hypotheses. Results: Univariate regressions were significant and robust (R2=.78, .70, .73, for reading, writing, and math fluency, respectively), with consistent effects of covariates, age, reaction time, and vocabulary; group and group moderation showed small effect sizes (<2%). Multivariate contrasts showed differential prediction across academic fluency outcomes for reaction time and vocabulary. Conclusions: The novelty of the present work is determining neurocognitive predictors for an important outcome (academic fluency), within and across fluency domains, across population (spina bifida versus typical), over a large developmental span, in the context of well-known covariates. Results offer insight into similarities and differences regarding prediction of different domains of academic fluency, with implications for addressing academic weakness in spina bifida, and for evaluating similar questions in other neurodevelopmental disorders. (JINS, 2019, 25, 249–265)
Over the past 50 years, research on children and adults with learning disabilities has seen significant advances. Neuropsychological research historically focused on the administration of tests sensitive to brain dysfunction to identify putative neural mechanisms underlying learning disabilities that would serve as the basis for treatment. Led by research on classifying and identifying learning disabilities, four pivotal changes in research paradigms have produced a contemporary scientific, interdisciplinary, and international understanding of these disabilities. These changes are (1) the emergence of cognitive science, (2) the development of quantitative and molecular genetics, (3) the advent of noninvasive structural and functional neuroimaging, and (4) experimental trials of interventions focused on improving academic skills and addressing comorbid conditions. Implications for practice indicate a need to move neuropsychological assessment away from a primary focus on systematic, comprehensive assessment of cognitive skills toward more targeted performance-based assessments of academic achievement, comorbid conditions, and intervention response that lead directly to evidence-based treatment plans. Future research will continue to cross disciplinary boundaries to address questions regarding the interaction of neurobiological and contextual variables, the importance of individual differences in treatment response, and an expanded research base on (a) the most severe cases, (b) older people with LDs, and (c) domains of math problem solving, reading comprehension, and written expression. (JINS, 2017, 23, 930–940)
Variation in annual soybean plantings contributes to uncertainty in supplies of and demand for soybean seed in the southeastern U.S. This study used an expenditure valuation approach in an hedonic analysis framework to estimate returns to soybean seed quality differentiation. Analysis of pooled cross-sectional and time series observations narrowed important quality characteristics to yield and disease resistance attributes. In general, unexpected environmental factors affect seed crops over time, and the demand for other performance attributes is less predictable than for expected yield attributes. The results also suggest that geographical location is not significantly related to sales of varietal soybean seed in the study area.
Covert orienting is related to the integrity of the midbrain, but the specificity of the relation is unclear. We compared covert orienting in three etiologies of congenital hydrocephalus (aqueductal stenosis [AS], Dandy-Walker malformation [DWM], and spina bifida myelomeningocele [SBM]—with and without tectal beaking) to explore the effects of midbrain and posterior fossa malformations. We hypothesized a stepwise order of group performance reflecting the degree of midbrain tectum dysmorphology. Performance on an exogenously cued covert orienting task was compared using repeated measures analysis of covariance, controlling for age. Individuals with SBM and tectal beaking demonstrated the greatest disengagement cost in the vertical plane, whereas individuals with AS performed as well as a typically developing (TD) group. Individuals with SBM but no tectal beaking and individuals with DWM showed greater disengagement costs in the vertical plane relative to the TD group, but better performance relative to the group with SBM and tectal beaking. Individuals with AS, DWM, and SBM and tectal beaking demonstrated poorer inhibition of return than TD individuals. Impairments in attentional disengagement in SBM are not attributable to the general effects of hydrocephalus, but are instead associated with specific midbrain anomalies that are part of the Chiari II malformation. (JINS, 2014, 20, 1–10)
Infants with Spina Bifida (SB) were compared to typically developing infants (TD) using a conjugate reinforcement paradigm at 6 months-of-age (n = 98) to evaluate learning, and retention of a sensory-motor contingency. Analyses evaluated infant arm-waving rates at baseline (wrist not tethered to mobile), during acquisition of the sensory-motor contingency (wrist tethered), and immediately after the acquisition phase and then after a delay (wrist not tethered), controlling for arm reaching ability, gestational age, and socioeconomic status. Although both groups responded to the contingency with increased arm-waving from baseline to acquisition, 15% to 29% fewer infants with SB than TD were found to learn the contingency depending on the criterion used to determine contingency learning. In addition, infants with SB who had learned the contingency had more difficulty retaining the contingency over time when sensory feedback was absent. The findings suggest that infants with SB do not learn motor contingencies as easily or at the same rate as TD infants, and are more likely to decrease motor responses when sensory feedback is absent. Results are discussed with reference to research on contingency learning in infants with and without neurodevelopmental disorders, and with reference to motor learning in school-age children with SB. (JINS, 2013, 19, 1–10)
We compared neuropsychological profiles in children with shunted hydrocephalus secondary to aqueductal stenosis (AS), a rare form of congenital hydrocephalus, and spina bifida myelomeningocele (SBM), a common form of congenital hydrocephalus. Participants were 180 children with shunted hydrocephalus grouped according to etiology: SBM (n = 151), AS (n = 29), and typically developing (TD; n = 60) individuals. The group with AS performed below the TD group on all tasks except for reading, and their overall performance was higher than the group with SBM, who had the lowest performance in the sample. Both clinical groups significantly differed from the TD group on tasks of spatial function, concept formation, motor function, and memory. Performance of the subgroup of AS children with normal cerebellum status approximated that of the TD group, while those with cerebellar anomalies performed lower than others with AS. Cerebellar abnormalities (present in the whole SBM group and in a subset of the AD group) are associated with more compromise of cognitive as well as motor function. (JINS, 2012, 18, 1–10)
Spatiotemporal brain activation profiles were obtained from 27 middle school students experiencing difficulties in reading comprehension as well as word-level skills (RD) and 23 age- and IQ-matched non-reading impaired students during performance of an oral pseudoword reading task using Magnetoencephalography (MEG). Based on their scores on standardized reading fluency tests 1 year later, students with RD who showed significant improvement were classified as Adequate Responders (AR) whereas those not demonstrating such gains were classified as Inadequate Responders (IR). At baseline, activation profiles of the AR group featured increased activity in the left supramarginal and angular gyri, as well as in the superior and middle temporal gyri, bilaterally compared to IR. The degree of activity in these regions was a significant predictor of the amount of subsequent gains in reading fluency. These results extend previous functional brain imaging findings of beginning readers, suggesting that recruitment of brain areas that typically serve as key components of the brain circuit for reading is an important factor in determining response to intervention in older struggling readers. (JINS, 2011, 17, 875–885)
Preschoolers with spina bifida (SB) were compared to typically developing (TD) children on tasks tapping mathematical knowledge at 36 months (n = 102) and 60 months of age (n = 98). The group with SB had difficulty compared to TD peers on all mathematical tasks except for transformation on quantities in the subitizable range. At 36 months, vocabulary knowledge, visual–spatial, and fine motor abilities predicted achievement on a measure of informal math knowledge in both groups. At 60 months of age, phonological awareness, visual–spatial ability, and fine motor skill were uniquely and differentially related to counting knowledge, oral counting, object-based arithmetic skills, and quantitative concepts. Importantly, the patterns of association between these predictors and mathematical performance were similar across the groups. A novel finding is that fine motor skill uniquely predicted object-based arithmetic abilities in both groups, suggesting developmental continuity in the neurocognitive correlates of early object-based and later symbolic arithmetic problem solving. Models combining 36-month mathematical ability and these language-based, visual–spatial, and fine motor abilities at 60 months accounted for considerable variance on 60-month informal mathematical outcomes. Results are discussed with reference to models of mathematical development and early identification of risk in preschoolers with neurodevelopmental disorder. (JINS, 2011, 17, 431–444)
Spina bifida meningomyelocele (SBM) is a neurodevelopmental disorder associated with intact word decoding and deficient text and discourse comprehension. This study investigated the ability to adjust reading in accordance with specified reading goals in 79 children and adolescents with SBM (9–19 years of age) and 39 controls (8–17 years of age). Both groups demonstrated slower reading times and enhanced comprehension when reading to study or to come up with a title than when reading for specific information or for entertainment. For both groups, verbal working memory contributed to comprehension performance in those reading conditions hypothesized to require more cognitive effort. Despite their sensitivity to the goals of reading, the group with SBM answered fewer comprehension questions correctly across all reading goal conditions. The results are discussed in relation to the hypothesized cognitive underpinnings of comprehension deficits in SBM and to current models of text comprehension. (JINS, 2010, 16, 517–525.)
The cerebellar hypothesis of dyslexia posits that cerebellar deficits are associated with reading disabilities and may explain why some individuals with reading disabilities fail to respond to reading interventions. We tested these hypotheses in a sample of children who participated in a grade 1 reading intervention study (n = 174) and a group of typically achieving children (n = 62). At posttest, children were classified as adequately responding to the intervention (n = 82), inadequately responding with decoding and fluency deficits (n = 36), or inadequately responding with only fluency deficits (n = 56). Based on the Bead Threading and Postural Stability subtests from the Dyslexia Screening Test-Junior, we found little evidence that assessments of cerebellar functions were associated with academic performance or responder status. In addition, we did not find evidence supporting the hypothesis that cerebellar deficits are more prominent for poor readers with “specific” reading disabilities (i.e., with discrepancies relative to IQ) than for poor readers with reading scores consistent with IQ. In contrast, measures of phonological awareness, rapid naming, and vocabulary were strongly associated with responder status and academic outcomes. These results add to accumulating evidence that fails to associate cerebellar functions with reading difficulties. (JINS, 2010, 16, 526–536.)
In the past 25 years, scientific understanding of dyslexia and other learning disabilities has seen rapid progress in domains involving definition and classification, neuropsychological correlates, neurobiological factors, and intervention. I discuss this progress, emphasizing the central organizing influence of research and theory on basic academic skills on identification and sampling issues. I also emphasize how neuropsychological approaches to dyslexia have evolved and the importance of an interdisciplinary perspective for understanding dyslexia. (JINS, 2009, 15, 501–508.)
IQ scores are volatile indices of global functional outcome, the final common path of an individual’s genes, biology, cognition, education, and experiences. In studying neurocognitive outcomes in children with neurodevelopmental disorders, it is commonly assumed that IQ can and should be partialed out of statistical relations or used as a covariate for specific measures of cognitive outcome. We propose that it is misguided and generally unjustified to attempt to control for IQ differences by matching procedures or, more commonly, by using IQ scores as covariates. We offer logical, statistical, and methodological arguments, with examples from three neurodevelopmental disorders (spina bifida meningomyelocele, learning disabilities, and attention deficit hyperactivity disorder) that: (1) a historical reification of general intelligence, g, as a causal construct that measures aptitude and potential rather than achievement and performance has fostered the idea that IQ has special status and that in studying neurocognitive function in neurodevelopmental disorders; (2) IQ does not meet the requirements for a covariate; and (3) using IQ as a matching variable or covariate has produced overcorrected, anomalous, and counterintuitive findings about neurocognitive function. (JINS, 2009, 15, 331–343.)
This review proposes a new taxonomy of automatic and controlled attention. The taxonomy distinguishes among the role of the attendee (puppet and robot, critic and actor), the attention process (stimulus orienting vs. response control), and the attention operation (activation vs. inhibition vs. adjustment), and identifies cognitive phenotypes by which attention is overtly expressed. We apply the taxonomy to four childhood attention disorders: attention deficit hyperactivity disorder, spina bifida meningomyelocele, traumatic brain injury, and acute lymphoblastic leukemia. Variations in attention are related to specific brain regions that support normal attention processes when intact, and produce disordered attention when impaired. The taxonomy explains group differences in behavioral inattention, hyperactivity, and impulsiveness, as well as medication response. We also discuss issues relevant to theories of the cognitive and neural architecture of attention: functional dissociations within and between automatic and controlled attention; the relative importance of type of brain damage and developmental timing to attention profile; cognitive-energetic models of attention and white matter damage; temporal processing deficits, attention deficits and cerebellar damage; and the issue of cognitive phenotypes as candidate endophenotypes. (JINS, 2008, 14, 673–690.)
Spina bifida meningomyelocele with hydrocephalus (SBM) is commonly associated with anomalies of the corpus callosum (CC). We describe MRI patterns of regional CC agenesis and relate CC anomalies to functional laterality based on a dichotic listening test in 90 children with SBM and 27 typically developing controls. Many children with SBM (n = 40) showed regional CC anomalies in the form of agenesis of the rostrum and/or splenium, and a smaller number (n = 20) showed hypoplasia (thinning) of all CC regions (rostrum, genu, body, and splenium). The expected right ear advantage (REA) was exhibited by normal controls and children with SBM having a normal or hypoplastic splenium. It was not shown by children with SBM who were left handed, missing a splenium, or had a higher level spinal cord lesion. Perhaps the right hemisphere of these children is more involved in processing some aspects of linguistic stimuli. (JINS, 2008, 14, 771–781.)
We investigated verb generation in children with spina bifida meningomyelocele (SBM; n = 55) and in typically developing controls (n = 32). Participants completed 6 blocks (40 trials each) of a task requiring them to produce a semantically related verb in response to a target noun and an additional 40 trials on which they were simply required to read target nouns aloud. After controlling for reading response time, groups did not differ significantly in verb generation response time or learning. Children with SBM produced more non-verb errors than controls and tended to repeat their mistakes over blocks. Verb generation performance was associated with brain volume measures in participants with SBM. Congenital cerebellar dysmorphology is associated with impaired performance in verb generation accuracy, although not with increased response times to produce verbs.(JINS, 2008, 14, 181–191.)
Learning and performance on a ballistic task were investigated in
children with spina bifida meningomyelocele (SBM), with either upper level
spinal lesions (n = 21) or lower level spinal lesions (n
= 81), and in typically developing controls (n = 35).
Participants completed three phases (20 trials each) of an elbow
goniometer task that required a ballistic arm movement to move a cursor to
one of two target positions on a screen, including (1) an initial
learning phase, (2) an adaptation phase with a gain
change such that recalibration of the ballistic arm movement was required,
and (3) a learning reactivation phase under the original gain
condition. Initial error rate, asymptotic error rate, and learning rate
did not differ significantly between the SBM and control groups. Relative
to controls, the SBM group had reduced volumes in the cerebellar
hemispheres and pericallosal gray matter (the region including the basal
ganglia), although only the pericallosal gray matter was significantly
correlated with motor adaptation. Congenital cerebellar dysmorphology is
associated with preserved motor skill learning on voluntary, nonreflexive
tasks in children with SBM, in whom the relative roles of the cerebellum
and basal ganglia may differ from those in the adult brain.
(JINS, 2006, 12, 598–608.)
Spina bifida myelomeningocele (SBM), a neural tube defect that is the
product of a complex pattern of gene-environment interactions, is
associated with naturally occurring, systematic variability in the neural
phenotype and in environmental factors that lead to systematic variability
in the cognitive phenotype. We characterize the basis for variability in
the cognitive phenotype of children with SBM with reference to a model of
key biological, cognitive, and environmental events unfolding over the
course of development from infancy to middle age. The cognitive phenotype
is not domain-specific, but represents manifestations of unobservable
constructs involving associative and assembled processing, the latter
directly reflecting the impact of the neural phenotype on core deficits
involving movement, timing, and attention orienting. The expression of the
cognitive phenotype is variable, being moderated by features of the neural
phenotype involving secondary CNS insults (such as hydrocephalus) that
impair assembled processing, as well as by environmental factors (such as
poverty, parenting, and education) that impair associative processing. The
preservation of strengths in associative processing depends in part on the
severity of the CNS deficits in SBM and the impact of the environment.
(JINS, 2006, 12, 285–296.)