Spina Bifida: Genes, Brain, and Development

Social Skills in Youth With Spina Bifida: A Longitudinal Multimethod Investigation Comparing Biopsychosocial Predictors

Objective

To examine the relative contributions of neuropsychological (attention and executive function), family (cohesion and conflict), and health (body mass index, lesion level, gross motor function) domains on social skills over time in youth with spina bifida (SB).

Methods

In all, 140 youth with SB (T1 mean age = 11.43 years) and their families participated in the study at baseline with an additional visit 2 years later. Study variables were assessed with multiple methods (questionnaire, medical chart review, observation, neuropsychological tests) and reporters (parents, teachers). Multivariate hierarchical linear regressions determined the predictive power of the three domains for T2 social skills.

Results

Neuropsychological variables accounted for significant variance in mother- and father-reported T2 social skills. Neither family nor health variables contributed significantly to later social skills when other domains were included in the model.

Conclusions

Neuropsychological factors are particularly important for social skill development in youth with SB. Findings can inform screening and intervention practices.

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.

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.

Motor sequence learning in children with spina bifida

Cognitive and motor problems are common in children with spina bifida (SB), particularly in those children with cerebral malformations (SBM). Little is known about how these conditions affect motor learning. This study examines motor sequence learning in children with SB, SBM, and healthy controls. Assessment consisted of neuropsychological tests, a simple drawing task, and a spatial motor sequence learning task. Implicit motor learning was unaffected in children with SB(M), and their sequence learning ability was also similar to that of controls. However, both groups (SB and SBM) showed impaired motor performance. The role of cerebellar malformation with SB(M) is discussed.

Factors associated with strabismus in spina bifida myelomeningocele

PURPOSE

Higher prevalence of strabismus in individuals with spina bifida myelomeningocele (SBM) has previously been attributed to hydrocephalus; however, SBM is associated with many other complications. This study investigates the relation between strabismus and other factors in SBM.

METHODS

Children aged 3 to 18 years with SBM (n = 112) received an eye examination including assessment of ocular alignment by cover or Hirschberg test. Gestational age, respiratory distress at birth, birth weight, maternal age at birth, number of shunt revisions, and spinal lesion level were also obtained. The relation between these factors and strabismus was analyzed.

RESULTS

Forty-two participants had strabismus. Maternal age (P = .4) and respiratory distress (P = .6) were not significantly related to strabismus. Lower birth weight was suggestive of a relation with strabismus (logistic regression, P = .05) and younger gestational age was related to strabismus (logistic regression, P = .01). Participants who had at least one shunt revision were more likely to have strabismus (Fisher's exact test, P = .038). Spinal lesion level was significantly related to strabismus with increased likelihood of strabismus for spinal lesions closer to the brain (Wald chi-square, 1,100 = 4.29, P = .038).

CONCLUSION

These findings indicate that several factors are associated with strabismus in SBM. Some of these factors (lower birth weight and younger gestational age) are associated with strabismus in the general population, whereas the association of strabismus and level of spinal lesion may be unique to SBM and may be related to the more severe brain dysmorphology associated with upper level spinal lesions.

Diffusion tensor imaging evaluation of white matter in adolescents with myelomeningocele and Chiari II malformation

BACKGROUND

Macrostructural abnormalities in cerebral white matter in patients with myelomeningocele are well known, but microstructural abnormalities are not as well studied.

OBJECTIVE

The aim of this study was to evaluate cerebral white matter in adolescents with myelomeningocele using diffusion tensor imaging (DTI), and to investigate the effects of ventricular dilation and CSF shunt presence on white matter microstructure in these patients.

MATERIALS AND METHODS

DTI and T1-weighted 3-D (T1-3-D) MRI were performed on nine adolescents with myelomeningocele and Chiari II malformation and nine age-matched controls. The fractional anisotropy (FA) and mean diffusivity (MD) values were measured and compared.

RESULTS

Significantly decreased FA and increased MD values were observed in most white matter regions and fibers in adolescents with myelomeningocele compared to controls. Further analysis in patients revealed significant changes in DTI parameters in hemispheres with enlarged lateral ventricles compared to those with normal ventricle size. In addition, a significant difference in FA values in the posterior limb of the internal capsule was found in the comparison of hemispheres in patients with or without CSF shunt catheters.

CONCLUSION

This study revealed widespread microstructural abnormalities in white matter in adolescents with myelomeningocele and Chiari II malformation. Ventricular dilation may have additional effects on white matter microstructure in this patient population. CSF shunt diversion effects on white matter may be multifactorial and need further investigation.

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.

Adolescent predictors of emerging adulthood milestones in youth with spina bifida

OBJECTIVE

To examine the predictive utility of demographic (illness status and SES), individual (neurocognitive functioning and intrinsic motivation), and family-based (parental intrusiveness) factors during adolescence on the achievement of emerging adulthood milestones in youth with and without spina bifida (SB).

METHODS

Questionnaire and observational data were collected from 14/15-year-old adolescents with SB, typically developing peers, mothers, and teachers. Emerging adulthood milestones (i.e., leaving home, attending college, employment, romantic relationship experience, and number of friendships) were assessed at ages 18/19 years in the full sample and subset of youth who graduated from high school.

RESULTS

Typically, developing youth were more likely to achieve milestones compared to youth with SB in the full sample but not when only high school graduates were compared. Executive function, SES, intrinsic motivation, and parental intrusiveness emerged as significant predictors for particular milestones.

CONCLUSIONS

Interventions targeting executive function, intrinsic motivation, and parenting behavior may facilitate achievement of emerging adulthood milestones.

The cerebellar dysplasia of Chiari II malformation as revealed by eye movements

INTRODUCTION

Chiari type II malformation (CII) is a developmental deformity of the hindbrain. We have previously reported that many patients with CII have impaired smooth pursuit, while few make inaccurate saccades or have an abnormal vestibuloocular reflex. In contrast, saccadic adaptation and visual fixation are normal. In this report, we correlate results from several eye movement studies with neuroimaging in CII. We present a model for structural changes within the cerebellum in CII.

METHODS

Saccades, smooth pursuit, the vestibulo-ocular reflex, and visual fixation were recorded in 21 patients with CII, aged 8-19 years and 39 age-matched controls, using an infrared eye tracker. Qualitative and quantitative MRI data were correlated with eye movements in 19 CII patients and 28 controls.

RESULTS

Nine patients with CII had abnormal eye movements. Smooth pursuit gain was subnormal in eight, saccadic accuracy abnormal in four, and vestibulo-ocular reflex gain abnormal in three. None had fixation instability. Patients with CII had a significantly smaller cerebellar volume than controls, and those with normal eye motion had an expanded midsagittal vermis compared to controls. However, patients with abnormal eye movements had a smaller (non-expanded) midsagittal vermis area, posterior fossa area and medial cerebellar volumes than CII patients with normal eye movements.

CONCLUSIONS

The deformity of CII affects the structure and function of the cerebellum selectively and differently in those with abnormal eye movements. We propose that the vermis can expand when compressed within a small posterior fossa in some CII patients, thus sparing its ocular motor functions.

Cognitive functions in children with myelomeningocele without hydrocephalus

OBJECTIVE

The aim of this study was to explore the separate effects of myelomeningocele (MMC) and hydrocephalus on intelligence and neuropsychological functions in a population-based series of children.

MATERIAL AND METHODS

Of the 69 children with MMC born in 1992-1999 in western Sweden, nine did not develop hydrocephalus. Eight of them participated in this study and were compared with age- and gender-matched children with MMC in combination with hydrocephalus and with controls.

RESULTS

Children with only MMC had an IQ of 103 compared with 75 in those with hydrocephalus added to the MMC and they had significantly better immediate and long-term memory and executive functions. When compared with controls, they had difficulty with learning and executive functions, but when the two children with an IQ of <70 were excluded, those with only MMC performed just as well as the controls.

CONCLUSION

Hydrocephalus rather than MMC in itself appeared to cause the cognitive deficits found in children with MMC.

Visual fixation in Chiari type II malformation

Chiari type II malformation is a congenital deformity of the hindbrain. Square wave jerks are horizontal involuntary saccades that interrupt fixation. Cerebellar disorders may be associated with frequent square wave jerks or saccadic oscillations such as ocular flutter. The effects of Chiari type II malformation on visual fixation are unknown. We recorded eye movements using an eye tracker in 21 participants with Chiari type II malformation, aged 8 to 19 years while they fixated a target for 1 minute. Thirty-eight age-matched healthy participants served as controls. Square wave jerks' parameters were similar in the 2 groups. Saccadic oscillations were not seen. Chiari type II malformation is not associated with pathological square wave jerks or abnormal saccadic oscillations. The congenital nature of this deformity may permit compensation that preserves stable visual fixation. Alternatively, the deformity of Chiari type II malformation may spare parts of the cerebellum that usually cause fixation instability when damaged.

The vestibulo-ocular reflex during active head motion in Chiari II malformation

BACKGROUND

Chiari type II malformation (CII) is a developmental anomaly of the cerebellum and brainstem, which are important structures for processing the vestibulo-ocular reflex (VOR). We investigated the effects of the deformity of CII on the angular VOR during active head motion.

METHODS

Eye and head movements were recorded using an infrared eye tracker and magnetic head tracker in 20 participants with CII [11 males, age range 8-19 years, mean (SD) 14.4 (3.2) years]. Thirty-eight age-matched healthy children and adolescents (21 males) constituted the control group. Participants were instructed to 'look' in darkness at the position of their thumb, placed 25 cm away, while they made horizontal and vertical sinusoidal head rotations at frequencies of about 0.5 Hz and 2 Hz. Parametric and non-parametric tests were used to compare the two groups.

RESULTS

The VOR gains, the ratio of eye to head velocities, were abnormally low in two participants with CII and abnormally high in one participant with CII.

CONCLUSION

The majority of participants with CII had normal VOR performance in this investigation. However, the deformity of CII can impair the active angular VOR in some patients with CII. Low gain is attributed to brainstem damage and high gain to cerebellar dysfunction.

Parents' personality and parenting stress in families of children with spina bifida

BACKGROUND

Spina bifida (SB) can place parents at risk for increased levels of parenting stress. Little is known, however, about the role of parents' intrapersonal resources. Therefore, based on ideas of the Disability-Stress-Coping Model, relations between the severity of SB, parents' personality traits and parenting stress were examined.

METHODS

Forty-six mothers and 37 fathers of children with SB (6-14 years) participated. Severity of SB (physical dysfunctions and cognitive functions), parental personality (Big Five) and parenting stress (Parenting Stress Index) were measured. Multiple regression analyses were performed.

RESULTS

The severity of the child's physical dysfunctions was positively associated with parenting stress. Extraversion (mothers only), emotional stability and agreeableness (fathers only) were negatively related to parenting stress. In the final model, 64% of the variance in mothers' and 67% of the variance in fathers' levels of parenting stress was explained. Parents' personality traits explained the largest proportions of variance in parenting stress.

CONCLUSION

Mobility, bladder and bowel dysfunctions in school-aged children with SB represent ongoing stressors for parents. Parents' intrapersonal resources of positive affectivity, however, are more important determinants of parental adjustment to SB than the child's physical dysfunctions.

Learning, memory and executive functions in children with hydrocephalus

AIMS

To explore learning, memory and executive abilities in children with hydrocephalus without learning disabilities, and to find out whether children with an isolated hydrocephalus differed from those with hydrocephalus in combination with myelomeningocele (MMC).

METHODS

Thirty-six children with an intelligence quotient (IQ) of >or=70 from a population of all the 107 children with hydrocephalus born in western Sweden in 1989-1993 were examined and compared with age- and gender-matched controls. The neuropsychological assessment of the school-aged child (NIMES) test battery was used.

RESULTS

The children with hydrocephalus differed significantly from controls in all functions apart from registration skills and recognition. Learning, memory and executive functions were all impaired. Twenty children with infantile hydrocephalus did not differ from those with hydrocephalus associated with MMC. Also, children with an IQ of >84 performed significantly worse than controls.

CONCLUSIONS

Despite an IQ of >or=70, children with hydrocephalus had significantly impaired learning, memory and executive functions. When major brain lesions resulting in learning disability had been excluded, the hydrocephalus, rather than the underlying aetiology, was most important for the development of cognitive functions.

Verb generation in children with spina bifida

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

Parents' social adjustment in families of children with spina bifida: a theory-driven review

OBJECTIVE

Five theoretical hypotheses about the impact of spina bifida (SB) on parents' social adjustment in the parent-child, the marital and the family-level relationship were tested.

METHODS

PsycInfo, Medline and reference lists were searched. This yielded 27 eligible reports. Effect sizes (Hedges' d) were computed to estimate the impact of SB.

RESULTS

Overall, the effects of SB were small to negligible on the affective dimensions of parents' relationships. The few effects that were found tended to be positive. The most important negative effects of SB were found in the parent-child relationship (parenting stress and overprotection).

CONCLUSIONS

Support was found for the resilience-disruption hypothesis, the role-division hypothesis and the miscarried-helping hypothesis, but not for the marital-disruption hypothesis or the marginality hypothesis.

Smooth ocular pursuit in Chiari type II malformation

Chiari type II malformation (CII) is a congenital anomaly of the cerebellum and brainstem, both important structures for processing smooth ocular pursuit. CII is associated with myelomeningocele and hydrocephalus. We investigated the effects of CII on smooth pursuit (SP) eye movements, and determined the effects of spinal lesion level, number of shunt revisions, nystagmus, and brain dysmorphology on SP. SP was recorded using an infrared eye tracker in 21 participants with CII (11 males, 10 females; age range 8-19y, mean 14y 3mo [SD 3y 2mo]). Thirty-eight healthy children (21 males, 17 females) constituted the comparison group. Participants followed a visual target moving sinusoidally at +/- 10 degrees amplitude, horizontally and vertically at 0.25 or 0.5Hz. SP gains, the ratio of eye to target velocities, were abnormal in the CII group with nystagmus (n= 8). The number of shunt revisions (range 0-10), brain dysmorphology, or spinal lesion level (n= 15 for lower and n= 6 for upper spinal lesion level) did not correlate with SP gains. SP is impaired in children with CII and nystagmus. Abnormal pursuit might be related to the CII dysgenesis or to effects of hydrocephalus. The lack of effect of shunt revisions and abnormal tracking in participants with nystagmus provide evidence that it is related primarily to the cerebellar and brainstem malformation.

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.

Saccadic adaptation in Chiari type II malformation

BACKGROUND

Saccadic adaptation corrects errors in saccadic amplitude. Experimentally-induced saccadic adaptation provides a method for studying motor learning. The cerebellum is a major participant in saccadic adaptation. Chiari type II malformation (CII) is a developmental deformity of the cerebellum and brainstem that is associated with spina bifida. We investigated the effects of CII on saccadic adaptation.

METHOD

We measured eye movements using an infrared eye tracker in 21 subjects with CII (CII group) and 39 typically developing children (control group), aged 8-19 years. Saccadic adaptation was induced experimentally using targets that stepped horizontally 120 to the right and then stepped backward 3 degrees during saccades.

RESULTS

Saccadic adaptation was achieved at the end of the adaptation phase in participants in each group. Saccadic amplitude gain decreased by 6.9% in the CII group and 9.3% in the control group. The groups did not differ significantly (p = 0.27). Amplitude gain reduction was significantly less in the CII participants who had multiple shunt revisions. Regression analyses revealed no effects of spinal lesion level, presence of nystagmus, or cerebellar vermis dysmorphology on saccadic adaptation.

CONCLUSION

The neural circuits involved in saccadic adaptation appear to be functionally intact in CII.

Peripersonal spatial attention in children with spina bifida: associations between horizontal and vertical line bisection and congenital malformations of the corpus callosum, midbrain, and posterior cortex

Horizontal and vertical line bisection was studied in 129 children and adolescents between 8 and 19 years of age, one group (n=32) of typically developing controls and one group (n=97) with spina bifida (SBM), a neurodevelopmental disorder associated with dysmorphology of the corpus callosum, posterior cortex, and midbrain. For each participant, structural brain MRIs were analyzed qualitatively to identify beaking of the midbrain tectum and corpus callosum agenesis and hypoplasia and quantitatively by segmentation and volumetric analyses of regional cortical white and gray matter. Each group showed the line length effect, whereby greater estimation errors are made with longer lines. The group with SBM differed from controls in terms of both accuracy and variability of line bisection. Children with SBM showed pseudoneglect, attending more than controls to left hemispace. The extent of rightward bisection bias was unrelated to right posterior brain volumes, although an intact corpus callosum during development moderated and normalized the exaggerated leftward line bisection bias. More children with SBM than controls attended to inferior hemispace. A normal midbrain and greater posterior cortex volume during development moderated and normalized the downward bias. Children with SBM showed more intra-subject variability than controls. Line bisection in children with SBM reflects three deficits: an exaggerated attentional bias to left hemispace, an abnormal attentional bias to inferior hemispace; and a larger zone of subjective uncertainty in bisection judgments.

Saccades in children with spina bifida and Chiari type II malformation

BACKGROUND

Saccades are essential for optimal visual function. Chiari type II malformation (CII) is a congenital anomaly of the cerebellum and brainstem, associated with spina bifida.

OBJECTIVE

To investigate the effects of CII on saccades and correlate saccadic parameters with brain MRI measurements.

METHODS

Saccades were recorded in 21 participants with CII, aged 8 to 19, using an infrared eye tracker. Thirty-nine typically developing children served as controls. Participants made saccades to horizontal and vertical target steps. Nineteen participants with CII had MRI. Regression analyses were used to investigate the effects of spinal lesion level, number of shunt revisions, presence of nystagmus, and midsagittal MRI measurements on saccades.

RESULTS

Saccadic amplitude gains, asymptotic peak velocities, and latencies did not differ between the control and CII groups (p > 0.01). No significant differences were found between saccadic gains, asymptotic peak velocities or latencies, and spinal lesion level, number of shunt revisions, presence of nystagmus, or MRI measurements.

CONCLUSIONS

Saccades were normal in most participants with Chiari II malformation (CII). Neural coding of saccades is robust and is typically not affected by the anatomic deformity of CII.

Parents' psychological adjustment in families of children with spina bifida: a meta-analysis

BACKGROUND

Spina Bifida (SB) is the second most common birth defect worldwide. Since the chances of survival in children with severe SB-forms have increased, medical care has shifted its emphasis from life-saving interventions to fostering the quality of life for these children and their families. Little is known, however, about the impact of SB on family adjustment. Reviewers have struggled to synthesize the few contradictory studies available. In this systematic review a new attempt was made to summarize the findings by using meta-analysis and by delimiting the scope of review to one concept of family adjustment: Parents' psychological adjustment. The questions addressed were: (a) do parents of children with SB have more psychological distress than controls? (b) do mothers and fathers differ? and (c) which factors correlate with variations in psychological adjustment?

METHODS

PsycInfo, Medline, and reference lists were scanned. Thirty-three relevant studies were identified of which 15 were eligible for meta-analysis.

RESULTS

SB had a negative medium-large effect on parents' psychological adjustment. The effect was more heterogeneous for mothers than for fathers. In the reviewed studies child factors (age, conduct problems, emotional problems, and mental retardation), parent factors (SES, hope, appraised stress, coping, and parenting competence), family factors (family income, partner relationship, and family climate), and environmental factors (social support) were found to be associated with variations in parents' psychological adjustment.

CONCLUSION

Meta-analysis proved to be helpful in organizing studies. Clinical implications indicate a need to be especially alert to psychological suffering in mothers of children with SB. Future research should increase sample sizes through multi-center collaborations.

Reading and writing skills in young adults with spina bifida and hydrocephalus

Reading and writing were studied in 31 young adults with spina bifida and hydrocephalus (SBH). Like children with this condition, young adults with SBH had better word decoding than reading comprehension, and, compared to population means, had lower scores on a test of writing fluency. Reading comprehension was predicted by word decoding and listening comprehension. Writing was predicted by fine motor finger function, verbal intelligence, and short-term and working memory. These findings are consistent with cognitive models of reading and writing. Writing, but not reading, was related to highest level of education achieved and writing fluency predicted several aspects of functional independence. Reading comprehension and writing remain deficient in adults with SBH and have consequences for educational attainments and functional independence.