Space-Based Inhibition of Return in Children With Spina Bifida

Hydrocephalus: A neuropsychological and theoretical primer

Hydrocephalus is a common neurological condition, the hallmark feature of which is an excess in production, or accumulation, of cerebrospinal fluid in the ventricles. Although it is associated with diffuse damage to paraventricular brain areas, patients are broadly typified by a particular pattern of cognitive impairments that include deficits in working memory, attention, and spatial abilities. There have, however, been relatively few neuropsychological accounts of the condition. Moreover, theories of the relationship between aetiology and impairment appear to have emerged in isolation of each other, and proffer fundamentally different accounts. In this primer, we aim to provide a comprehensive and contemporary overview of hydrocephalus for the neuropsychologist, covering cognitive sequelae and theoretical interpretations of their origins. We review clinical and neuropsychological assays of cognitive profiles, along with the few studies that have addressed more integrative behaviours. In particular, we explore the distinction between congenital or early-onset hydrocephalus with a normal-pressure variant that can be acquired later in life. The relationship between these two populations is a singularly interesting one in neuropsychology since it can allow for the examination of typical and atypical developmental trajectories, and their interaction with chronic and acute impairment, within the same broad neurological condition. We reflect on the ramifications of this for our subject and suggest avenues for future research.

A scoping review of cognition in spina bifida and its consequences for activity and participation throughout life

Aim

The aim of this scoping review was to summarise findings concerning cognitive characteristics in people with spina bifida and explain how cognitive factors influence activities and participation in different areas and stages of life.

Methods

PubMed, Psych INFO, ERIC, Scopus, CINAHL and the Cochrane Library were searched for English language papers published in 2000–2018. A total of 92 papers were selected and quality was assessed according to the McMaster criteria. The results were presented related to body functions, activity and participation from the International Classification of Function and Health, ICF.

Results

People with spina bifida tended to have a lower IQ than those without. The majority also had cognitive difficulties manifested in problems with language, perception, memory, executive and attentional functions. Those difficulties affected activity and participation in all life domains in ICF. This may affect medical adherence and responsibility and by extension the prevention of secondary complications.

Conclusion

It is important for caregivers, professionals and especially individuals with spina bifida themselves to understand and handle both physical and cognitive consequences in all life circumstances. Having insight into one’s own assets and difficulties paves the way to managing life challenges, which could enhance health, self‐management and participation in society.

Neurobehavioral outcomes in patients with myelomeningocele

This paper describes some of the more common patterns in neurobehavioral deficits and their underlying neuroanatomical basis in myelomeningocele (MMC). Patients with MMC can face a lifetime of specific organ system dysfunction, chief among them spinal cord malformations, orthopedic issues, hydrocephalus, and urological disabilities. In addition, patients can experience specific patterns of neurobehavioral difficulties due to the changes in neuroanatomy associated with the open spinal defect. Although there is variability in these patterns, some trends have been described among MMC patients. It is thought that early recognition of these potential neurobehavioral deficits by treating neurosurgeons and other members of the treatment team could lead to earlier intervention and positively impact the overall outcome for patients. Neurodevelopmental and neurobehavioral follow-up assessments are recommended to help guide planning for relevant treatments or accommodations.

Cognitive control and associated neural correlates in adults with spina bifida myelomeningocele

OBJECTIVE

Accelerated aging can occur in adult survivors of neurodevelopmental disorders, but has been narrowly studied in spina bifida myelomeningocele (SBM). Since discrete aspects of cognitive control and related neural network macrostructure deteriorate in normal aging, the specificity and trajectory of cognition and neuropathology incurred across adulthood in SBM were examined.

METHOD

Adults (N = 120) with and without SBM completed working memory span and manipulation tasks, and an inhibitory control task. A subset (n = 53) underwent structural MRI. Effects of group, age, and their interaction on performance and select gray matter volumes were examined.

RESULTS

Adults with SBM had significantly poorer working memory accuracy and overall inhibitory control performance than typical peers. Age negatively predicted inhibitory control. Group × Age significantly interacted on span accuracy; advanced age related to diminished performance in typical adults, but not in adults with SBM. SBM related to disproportionately enlarged cortical and putamen and reduced hippocampus volumes. Group × Age significantly interacted on cortical, but not subcortical gray matter volumes. Dorsolateral prefrontal, hippocampus, and putamen volumes negatively correlated with cognitive performance.

CONCLUSIONS

Supporting previous literature, current findings elucidated a profile of executive impairment in SBM that was maintained in a parallel maturational trajectory to typical aging. Accelerated aging in cognitive control or subcortical gray matter was not supported in SBM. However, reductions in anterior and posterior cortical regions were exacerbated in older adults with SBM compared with typical peers. Overall results supported persistent anomalous neurodevelopmental maturation across the life span in SBM that related to diminished cognitive control. (PsycINFO Database Record

Neurocognitive predictors of mathematical processing in school-aged children with spina bifida and their typically developing peers: Attention, working memory, and fine motor skills

OBJECTIVE

Math and attention are related in neurobiological and behavioral models of mathematical cognition. This study employed model-driven assessments of attention and math in children with spina bifida myelomeningocele (SBM), who have known math difficulties and specific attentional deficits, to more directly examine putative relations between attention and mathematical processing. The relation of other domain general abilities and math was also investigated.

METHOD

Participants were 9.5-year-old children with SBM (n = 44) and typically developing children (n = 50). Participants were administered experimental exact and approximate arithmetic tasks, and standardized measures of math fluency and calculation. Cognitive measures included the Attention Network Test (ANT), and standardized measures of fine motor skills, verbal working memory (WM), and visual-spatial WM.

RESULTS

Children with SBM performed similarly to peers on exact arithmetic, but more poorly on approximate and standardized arithmetic measures. On the ANT, children with SBM differed from controls on orienting attention, but not on alerting and executive attention. Multiple mediation models showed that fine motor skills and verbal WM mediated the relation of group to approximate arithmetic; fine motor skills and visual-spatial WM mediated the relation of group to math fluency; and verbal and visual-spatial WM mediated the relation of group to math calculation. Attention was not a significant mediator of the effects of group for any aspect of math in this study.

CONCLUSION

Results are discussed with reference to models of attention, WM, and mathematical cognition.

Relations between volumetric measures of brain structure and attentional function in spina bifida: utilization of robust statistical approaches

OBJECTIVE

Weak structure-function relations for brain and behavior may stem from problems in estimating these relations in small clinical samples with frequently occurring outliers. In the current project, we focused on the utility of using alternative statistics to estimate these relations.

METHOD

Fifty-four children with spina bifida meningomyelocele performed attention tasks and received MRI of the brain. Using a bootstrap sampling process, the Pearson product-moment correlation was compared with 4 robust correlations: the percentage bend correlation, the Winsorized correlation, the skipped correlation using the Donoho-Gasko median, and the skipped correlation using the minimum volume ellipsoid estimator.

RESULTS

All methods yielded similar estimates of the relations between measures of brain volume and attention performance. The similarity of estimates across correlation methods suggested that the weak structure-function relations previously found in many studies are not readily attributable to the presence of outlying observations and other factors that violate the assumptions behind the Pearson correlation.

CONCLUSIONS

Given the difficulty of assembling large samples for brain-behavior studies, estimating correlations using multiple, robust methods may enhance the statistical conclusion validity of studies yielding small, but often clinically significant, correlations.

Covert orienting in three etiologies of congenital hydrocephalus: the effect of midbrain and posterior fossa dysmorphology

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.

Leveling the playing field: attention mitigates the effects of intelligence on memory

Effective attention and memory skills are fundamental to typical development and essential for achievement during the formal education years. It is critical to identify the specific mechanisms linking efficiency of attentional selection of an item and the quality of its memory retention. The present study capitalized on the spatial cueing paradigm to examine the role of selection via suppression in modulating children and adolescents' memory encoding. By varying a single parameter, the spatial cueing task can elicit either a simple orienting mechanism (i.e., facilitation) or one that involves both target selection and simultaneous suppression of competing information (i.e., IOR). We modified this paradigm to include images of common items in target locations. Participants were not instructed to learn the items and were not told they would be completing a memory test later. Following the cueing task, we imposed a 7-min delay and then asked participants to complete a recognition memory test. Results indicated that selection via suppression promoted recognition memory among 7-17year-olds. Moreover, individual differences in the extent of suppression during encoding predicted recognition memory accuracy. When basic cueing facilitated orienting to target items during encoding, IQ was the best predictor of recognition memory performance for the attended items. In contrast, engaging suppression (i.e., IOR) during encoding counteracted individual differences in intelligence, effectively improving recognition memory performance among children with lower IQs. This work demonstrates that engaging selection via suppression during learning and encoding improves memory retention and has broad implications for developing effective educational techniques.

Examination of frontal and parietal tectocortical attention pathways in spina bifida meningomyelocele using probabilistic diffusion tractography

Abnormalities of the midbrain tectum are common but variable malformations in spina bifida meningomyelocele (SBM) and have been linked to neuropsychological deficits in attention orienting. The degree to which variations in tectum structure influence white matter (WM) connectivity to cortical regions is unknown. To assess the relationship of tectal structure and connectivity to frontal and parietal cortical regions, probabilistic diffusion tractography was performed on 106 individuals (80 SBM, 26 typically developing [TD]) to isolate anterior versus posterior tectocortical WM pathways. Results showed that those with SBM exhibited significantly reduced tectal volume, along with decreased fractional anisotropy (FA) in posterior but not anterior tectocortical WM pathways when compared with TD individuals. The group with SBM also showed greater within-subject discrepancies between frontal and parietal WM integrity compared with the TD group. Of those with SBM, qualitative classification of tectal beaking based on radiological review was associated with increased axial diffusivity across both anterior and posterior tectocortical pathways, relative to individuals with SBM and a normal appearing tectum. These results support previous volumetric findings of greater impairment to posterior versus anterior brain regions in SBM, and quantifiably relate tectal volume, tectocortical WM integrity, and tectal malformations in this population.

Motor contingency learning and infants with Spina Bifida

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.

Inhibition of return: Twenty years after

When responding to a suddenly appearing stimulus, we are slower and/or less accurate when the stimulus occurs at the same location of a previous event than when it appears in a new location. This phenomenon, often referred to as inhibition of return (IOR), has fostered a huge amount of research in the last 20 years. In this selective review, which introduces a Special Issue of Cognitive Neuropsychology dedicated to IOR, we discuss some of the methods used for eliciting IOR and its boundary conditions. We also address its debated relationships with orienting of attention, succinctly review findings of altered IOR in normal elderly and neuropsychiatric patients, and present results concerning its possible neural bases. We conclude with an outline of the papers collected in this issue, which offer a more in-depth treatment of behavioural, neural, and theoretical issues related to IOR.

Cerebellar motor function in spina bifida meningomyelocele

Spina bifida meningomyelocele (SBM), a congenital neurodevelopmental disorder, involves dysmorphology of the cerebellum, and its most obvious manifestations are motor deficits. This paper reviews cerebellar neuropathology and motor function across several motor systems well studied in SBM in relation to current models of cerebellar motor and timing function. Children and adults with SBM have widespread motor deficits in trunk, upper limbs, eyes, and speech articulators that are broadly congruent with those observed in adults with cerebellar lesions. The structure and function of the cerebellum are correlated with a range of motor functions. While motor learning is generally preserved in SBM, those motor functions requiring predictive signals and precise calibration of the temporal features of movement are impaired, resulting in deficits in smooth movement coordination as well as in the classical cerebellar triad of dysmetria, ataxia, and dysarthria. That motor function in individuals with SBM is disordered in a manner phenotypically similar to that in adult cerebellar lesions, and appears to involve similar deficits in predictive cerebellar motor control, suggests that age-based cerebellar motor plasticity is limited in individuals with this neurodevelopmental disorder.

Early information processing among infants with and without spina bifida

This study focuses on the development of early visual information processing among infants with spina bifida (SB) compared to typically developing infants using the habituation-dishabituation paradigm. Analyses were conducted in two stages. First infants were evaluated to determine if 18-month old infants (SB=47; Control=40) differed in their ability to shift attention and habituate to two female faces, as well as their responses to composite and novel stimuli. Second, relations between these variables and infant motor and mental functioning were evaluated. The results of the study indicated that difficulties with visual attention skills can be detected as early as 18 months of age among infants with SB. Infants with SB differed significantly from controls on attention getting. Although there were no differences found on habituation and composite tasks, infants with SB differed significantly from controls on their ability to dishabituate. Implications are discussed.

The cognitive phenotype of spina bifida meningomyelocele

A cognitive phenotype is a product of both assets and deficits that specifies what individuals with spina bifida meningomyelocele (SBM) can and cannot do and why they can or cannot do it. In this article, we review the cognitive phenotype of SBM and describe the processing assets and deficits that cut within and across content domains, sensory modality, and material, including studies from our laboratory and other investigations. We discuss some implications of the SBM cognitive phenotype for assessment, rehabilitation, and research.

Mathematical learning disabilities in special populations: phenotypic variation and cross-disorder comparisons

What is mathematical learning disability (MLD)? The reviews in this special issue adopt different approaches to defining the construct of MLD. Collectively, they demonstrate the current status of efforts to establish a consensus definition and the challenges faced in this endeavor. In this commentary, we reflect upon the proposed pathways to mathematical learning difficulties and disabilities presented across the reviews. Specifically we consider how each of the reviews contributes to identifying the MLD phenotype by specifying the range of assets and deficits in mathematics, identifying sources of individual variation, and characterizing the natural progression of MLD over the life course. We show how principled comparisons across disorders address issues about the cognitive and behavioral co-morbidities of MLD, and whether commonalities in brain dysmorphology are associated with common mathematics performance profiles. We project the status of MLD research ten years hence with respect to theoretical gains, advances in methodology, and principled intervention studies.

Why IQ is not a covariate in cognitive studies of neurodevelopmental disorders

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.

Mathematical development in spina bifida

Spina bifida (SB) is a neural tube defect diagnosed before or at birth that is associated with a high incidence of math disability often without co-occurring difficulties in reading. SB provides an interesting population within which to examine the development of mathematical abilities and disability across the lifespan and in relation to the deficits in visual-spatial processing that are also associated with the disorder. An overview of math and its cognitive correlates in preschoolers, school-age children and adults with SB is presented including the findings from a longitudinal study linking early executive functions in infancy to the development of later preschool and school age math skills. These findings are discussed in relation to socio-historical perspectives on math education and implications for intervention and directions for further research are presented.

Sustained attention in children with two etiologies of early hydrocephalus

Several studies have shown that children with spina bifida meningomyelocele (SBM) and hydrocephalus have attention problems on parent ratings and difficulties in stimulus orienting associated with a posterior brain attention system. Less is known about response control and inhibition associated with an anterior brain attention system. Using the Gordon Vigilance Task (Gordon, 1983), we studied error rate, reaction time, and performance over time for sustained attention, a key anterior attention function, in 101 children with SBM, 17 with aqueductal stenosis (AS; another condition involving congenital hydrocephalus), and 40 typically developing controls (NC). In SBM, we investigated the relation between cognitive attention and parent ratings of inattention and hyperactivity and explored the impact of medical variables. Children with SBM did not differ from AS or NC groups on measures of sustained attention, but they committed more errors and responded more slowly. Approximately one-third of the SBM group had attention symptoms, although parent attention ratings were not associated with task performance. Hydrocephalus does not account for the attention profile of children with SBM, which also reflects the distinctive brain dysmorphologies associated with this condition.

Characteristics of a spina bifida population including North American Caucasian and Hispanic individuals

BACKGROUND

Meningomyelocele (MM) is a common human birth defect. MM is a disorder of neural development caused by contributions from genes and environmental factors that result in the NTD and lead to a spectrum of physical and neurocognitive phenotypes.

METHODS

A multidisciplinary approach has been taken to develop a comprehensive understanding of MM through collaborative efforts from investigators specializing in genetics, development, brain imaging, and neurocognitive outcome. Patients have been recruited from five different sites: Houston and the Texas-Mexico border area; Toronto, Canada; Los Angeles, California; and Lexington, Kentucky. Genetic risk factors for MM have been assessed by genotyping and association testing using the transmission disequilibrium test.

RESULTS

A total of 509 affected child/parent trios and 309 affected child/parent duos have been enrolled to date for genetic association studies. Subsets of the patients have also been enrolled for studies assessing development, brain imaging, and neurocognitive outcomes. The study recruited two major ethnic groups, with 45.9% Hispanics of Mexican descent and 36.2% North American Caucasians of European descent. The remaining patients are African-American, South and Central American, Native American, and Asian. Studies of this group of patients have already discovered distinct corpus callosum morphology and neurocognitive deficits that associate with MM. We have identified maternal MTHFR 667T allele as a risk factor for MM. In addition, we also found that several genes for glucose transport and metabolism are potential risk factors for MM.

CONCLUSIONS

The enrolled patient population provides a valuable resource for elucidating the disease characteristics and mechanisms for MM development.

Puppets, robots, critics, and actors within a taxonomy of attention for developmental disorders

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.

Factors of biological risk and reserve associated with executive behaviors in children and adolescents with spina bifida myelomeningocele

This study examined differences between healthy children (n = 35) and those with spina bifida myelomeningocele (SBM; n = 42) on the Behavior Rating Inventory of Executive Function (BRIEF), a measure of executive function behaviors. It also examined whether aspects of biological risk associated with SBM and reserve factors within the family could account for variability in BRIEF scores for children and adolescents with SBM. Patients in the SBM group exhibited more problems than both published norms and a local comparison group of healthy children in metacognition but not behavior regulation. Behavior regulation problems in children with SBM were predicted by parent psychological distress. More shunt-related surgeries and history of seizures predicted poorer metacognitive abilities.

Prospective, declarative, and nondeclarative memory in young adults with spina bifida

The consequences of congenital brain disorders for adult cognitive function are poorly understood. We studied different forms of memory in 29 young adults with spina bifida meningomyelocele (SBM), a common and severely disabling neural tube defect. Nondeclarative and semantic memory functions were intact. Working memory was intact with low maintenance and manipulation requirements, but impaired on tasks demanding high information maintenance or manipulation load. Prospective memory for intentions to be executed in the future was impaired. Immediate and delayed episodic memory were poor. Memory deficits were exacerbated by an increased number of lifetime shunt revisions, a marker for unstable hydrocephalus. Memory status was positively correlated with functional independence, an important component of quality of life.

A model of neurocognitive function in spina bifida over the life span

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.

Räumlich-kognitive Fähigkeiten von Kindern mit Spina bifida

Zusammenfassung: In dieser Studie wurden die kognitiven und räumlichen Fähigkeiten von Kindern mit Spina bifida umfassend untersucht. Bei einer systematischen Diagnose der räumlich-kognitiven Fähigkeiten konnte erstmals gezeigt werden, dass Kinder mit Spina bifida im Vergleich zu einer hinsichtlich Alter, Geschlecht und Verbal-IQ gematchten Kontrollgruppe sowohl in den räumlich-kognitiven Faktoren räumliche Veranschaulichung, räumliche Orientierung und mentale Rotation als auch in einer räumlichen Kurzzeitgedächtnisaufgabe signifikant schlechter abschnitten. Darüber hinaus zeigten Kinder mit Spina bifida eine signifikant schlechtere Orientierungsleistung in einem virtuellen Umgebungsraum. Es fanden sich Korrelationen zwischen den räumlichen Fähigkeiten und dem Lauflernalter der Kinder mit Spina bifida.