MRI morphometric study and correlation with cognitive functions in young adults shunted for congenital hydrocephalus related to 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.

Thinner peripapillary retinal nerve fibre layer and macular retinal thickness in adolescents with surgically treated hydrocephalus in infancy

PURPOSE

To map the morphology of the retina and optic disc in adolescents with surgically treated hydrocephalus (HC) in infancy and to compare the results with healthy controls.

METHODS

The study comprised 26 adolescents (16 male, mean age 15 years) with HC and 31 sex- and aged-matched controls. The following optical coherence tomography (OCT) parameters were obtained: macular retinal thickness (MRT) and volume (MRV), thickness of the macular and peripapillary retinal nerve fibre layer (ppRNFL), and area of the optic disc, cup and rim.

RESULTS

The MRT was thinner amongst those with HC compared with controls (right eye (RE) 262.2 ± 15.3 and 275.8 ± 15.1 μm; p = 0.0051), and the MRV was smaller (RE 7.37 ± 0.36 and 7.83 ± 0.35 mm³ ; p = 0.0002). The HC group showed a thinner ppRNFL (RE 88.3 ± 14.9 and 103.5 ± 8.1 μm; p = 0.0002) but a thicker central macular RNFL (RE 11.6 ± 10.4 and 2.07 ± 3.00 μm; p = <0.0001) and foveal minimum (RE 211.1 ± 32.0 and 186.3 ± 15.9 μm; p = 0.0013). Optic disc variables showed no difference between groups. Correlations were found in the HC group between best corrected visual acuity (expressed in logMAR) and ppRNFL (RE r = -0.56, p = 0.018), and disc area (RE r = -0.52, p = 0.033).

CONCLUSION

Thinner ppRNFL and MRT and smaller MRV were found in adolescents with surgically treated HC in infancy compared with controls. In contrast, the central macular RNFL and foveal minimum were thicker. Further studies are required to evaluate the diagnostic value of OCT to indicate increased intracranial pressure timely and follow-up in individuals with surgically treated HC.

Neurodevelopmental outcomes after ventriculoperitoneal shunt placement in children with non-infectious hydrocephalus: a meta-analysis

BACKGROUND

Hydrocephalus is diagnosed when an accumulating amount of cerebrospinal fluid (CSF) fails to circulate and/or absorbed in the ventricular system. Based on its etiology, hydrocephalus can be classified into infectious and non-infectious hydrocephalus. In children, non-infectious hydrocephalus includes congenital hydrocephalus, posthemorrhagic hydrocephalus, neural tube defect-related hydrocephalus, and tumor-related hydrocephalus. Regardless of the cause, a CSF diversion device is placed to divert the excess fluid from the ventricles into peritoneal cavity. Among all, ventriculoperitoneal (VP) shunt is arguably the most commonly used CSF diversion device to date. Until now, the long-term neurodevelopmental impact of VP shunt placement in non-infectious hydrocephalus patients remained unclear.

OBJECTIVE

This study aims to evaluate the neurodevelopmental outcomes in children with non-infectious hydrocephalus who had VP shunt placement.

MATERIALS AND METHODS

Systematic searches were performed using PubMed, Google Scholar, Scopus databases, and reference lists. Publications that fulfilled the inclusion criteria were included in the meta-analysis. Calculation of Mantel-Haezel risk ratio (RR) was applied, and heterogeneity index (I²) test was used to evaluate the existence of heterogeneity in all studies. Risk of bias was assessed based on the criteria from the Newcastle-Ottawa Scale (NOS).

RESULTS

Of the 1929 studies identified, 12 publications were concluded to have fulfilled the inclusion criteria. Results from the meta-analysis showed that the risks of cerebral palsy, visual and hearing impairment, epilepsy, or seizures are significantly higher in children with non-infectious hydrocephalus who already had VP shunt placement (shunted non-infectious hydrocephalus, S-NIH) compared to that of the healthy control. The meta-analysis on intelligent quotient (IQ) and mental development index (MDI) showed that S-NIH children tend to score lower IQ and acquire risk of having mental development delay. On motoric development, S-NIH children scored lower motoric score and have significantly higher risk of motor development delay compared to control. Although normal children tend to have more internalizing behavior compared to S-NIH children, overall assessment on the risk of behavioral abnormalities showed that the differences between these two groups are insignificant.

CONCLUSION

S-NIH children have significantly higher risks of disabilities and mental and motoric development delays; thus, planning on continuous rehabilitation for children with non-infectious hydrocephalus who already had placement of VP shunt is important to acquire their optimum potentials and quality of life.

Brain malformations and cognitive performance in spina bifida

AIM

To systematically characterize radiological features of patients with spina bifida, their relationship to cognitive function, and differences between spina bifida aperta (SBA) and spina bifida occulta (SBO).

METHOD

In a retrospective study of 265 patients (117 females, 148 males; median age at imaging 11y, range 1-47y; SBA n=206, SBO n=59), the radiological phenotype was assessed through magnetic resonance imaging (MRI) (SBA n=171, SBO n=59). In 126 patients (SBA n=116, SBO n=10) Kaufman Assessment Battery for Children (KABC) or Wechsler Intelligence Scale for Children, Fourth Edition (WISC-IV) and Wechsler Adult Intelligence Scale, Fourth Edition (WAIS-IV) were performed.

RESULTS

Patients with spina bifida show numerous brain malformations, always present for SBA but rarely for SBO. The most frequent brain malformations in SBA included abnormal corpus callosum (69%), hypoplastic pons (50%), and hypoplastic mesencephalon (20%). Cognitive total IQ scores were below average in 44% (KABC) to 49% (WISC-IV) of children with SBA, while almost all children with SBO scored at least average. Stenogyria (p=0.006), pons (p=0.003), and mesencephalon hypoplasia (p=0.01) correlated with lower total IQ score and verbal comprehension. Various brain malformations correlate significantly with several cognitive domains, while lesion level only correlates with processing speed.

INTERPRETATION

IQ scores were significantly lower in patients with SBA than in patients with SBO. Verbal competence, perceptual reasoning, and working memory were significantly impaired for SBA and correlated with stenogyria and abnormalities of the midbrain and corpus callosum.

WHAT THIS PAPER ADDS

Brain malformations occur more frequently in spina bifida aperta (SBA) than in spina bifida occulta (SBO). Cognitive impairment is less frequent in SBO. Hydrocephalus, stenogyria, midbrain, and corpus callosum abnormalities are associated with lower cognitive function. Difference in prognosis in SBO versus SBA can alter prenatal counselling.

The impact of cerebral anomalies on cognitive outcome in patients with spina bifida: A systematic review

BACKGROUND

Spina bifida is the most common congenital birth defect affecting the central nervous system. Given the frequent association of cerebral anomalies, spina bifida is not a single developmental abnormality of the central nervous system. Patients with spina bifida typically perform below average on cognitive tasks. It has been hypothesized that associated cerebral anomalies as well negatively affect cognition in spina bifida patients.

OBJECTIVE

This study aims to review the impact of cerebral anomalies on cognitive outcome in patients with spina bifida.

METHODS

A systematic search of multiple databases, including Pubmed, Embase, Web of Science and The Cochrane Central Register of Controlled Trials, was performed. All relevant primary research articles were included. All included articles were methodologically evaluated using a critical appraisal checklist.

RESULTS

In total 27 articles were included in this systematic review. A significant impact of different cerebral anomalies on cognition was found. More specifically, hydrocephalus, Chiari malformation type II and anomalies of the corpus callosum, central executive network, default mode network, cortical thickness and gyrification, fornix, grey matter volume and total brain volume were found to have a significant impact on cognitive outcome. The presence of a CSF shunt was also negatively associated with cognition. The results on Chiari malformation type II decompression and CSF shunt complications are inconsistent.

CONCLUSION

Associated cerebral anomalies have a significant impact on cognitive outcome in patients with spina bifida. The interrelatedness of the different cerebral anomalies makes it difficult to distinguish their individual impact on cognition.

Pediatric hydrocephalus: systematic literature review and evidence-based guidelines. Part 10: Change in ventricle size as a measurement of effective treatment of hydrocephalus

OBJECT

The objective of this systematic review is to answer the following question: Does ventricle size after treatment have a predictive value in determining the effectiveness of surgical intervention in pediatric hydrocephalus?

METHODS

The US National Library of Medicine PubMed/MEDLINE database and the Cochrane Database of Systematic Reviews were searched using MeSH headings and key words relevant to change in ventricle size after surgical intervention for hydrocephalus in children. An evidentiary table was assembled summarizing the studies and the quality of evidence (Classes I-III).

RESULTS

Six articles satisfied inclusion criteria for the evidentiary tables for this part of the guidelines. All were Class III retrospective studies. CONCLUSIONS/RECOMMENDATIon: There is insufficient evidence to recommend a specific change in ventricle size as a measurement of the effective treatment of hydrocephalus and as a measurement of the timing and effectiveness of treatments including ventriculoperitoneal shunts and third ventriculostomies.

STRENGTH OF RECOMMENDATION

Level III, unclear clinical certainty.

Unilateral cortical hyperexcitability in congenital hydrocephalus: a TMS study

INTRODUCTION

Changes in cortical excitability are considered to play an important role in promoting brain plasticity both in healthy people and in neurological diseases. Hydrocephalus is a brain development disorder related to an excessive accumulation of cerebrospinal fluid (CSF) in the ventricular system. The functional relevance of cortical structural changes described in this disease is largely unexplored in human. We investigated cortical excitability using multimodal transcranial magnetic stimulation (TMS) in a case of congenital hydrocephalus with almost no neurological signs.

METHODS

A caucasian 40 years old, ambidextrous and multilingual woman affected by occult spina bifida and congenital symmetrical hydrocephalous underwent a TMS study. The intracortical and interhemispheric paired pulse paradigms were used, together with the mapping technique.

RESULTS

No significant differences were found in the resting motor thresholds between the two hemispheres. Instead, the intracortical excitability curves were statistically different between the two hemispheres (with short intracortical inhibition (SICI) being strongly reduced and intracortical facilitation (ICF) enhanced in the right one), and the interhemispheric curves showed a general hyper-excitability on the right hemisphere (when conditioned by the left one) and a general hypo-excitability in the left hemisphere (when conditioned by the right one). It is noteworthy that an asymmetric right hemisphere (RH) change of excitability was observed by means of mapping technique.

CONCLUSION

We hypothesize that in this ambidextrous subject, the observed RH hyper-excitability could represent a mechanism of plasticity to preserve functionality of specific brain areas possibly devoted to some special skills, such as multilingualism.

Maple syrup urine disease (MSUD): a case with long-term follow-up after liver transplantation

Maple syrup urine disease (MSUD) is a rare hereditary metabolic condition where the body is unable to breakdown amino acids causing toxic buildup. Acute and long-term management of MSUD involves a restricted diet and regular monitoring of amino acid levels; however, more recently liver transplants have been shown to be successful in treating this condition. Even with successful management of MSUD there is evidence from pediatric cases that shows a distinct pattern of neurocognitive deficits associated with this condition, including impaired nonverbal skills and psychomotor functioning with relatively intact verbal abilities. In the present paper, we report an adult case of MSUD with associated neurocognitive deficits and functional limitations following liver transplantation. Neuroimaging revealed no structural abnormalities, while the results from the neuropsychological evaluation showed impairment in visual-spatial processing, attention, executive functioning, and psychomotor abilities, with relative strengths in verbal skills. The patient also showed reduced adaptive functioning and mild anxiety. This case demonstrates neurocognitive deficiencies within the context of normal magnetic resonance imaging. The possible underlying mechanism of this neuropsychological profile is discussed in relation to other neurodevelopmental models.

Parent ratings of executive functioning in children with shunted hydrocephalus

OBJECTIVES

The present study examined the executive functioning of a group of children with a history of communicating hydrocephalus and how their level of functioning was correlated with parent ratings of executive functioning.

METHODS

The study examined the executive functioning of 39 shunted children with a history of hydrocephalus and 20 healthy peers. Additionally, parents of both groups of children completed the Behavior Rating Inventory of Executive Function (BRIEF) to assess the parents' perceptions of their children's executive functioning. Finally, the study investigated the relationship between the shunted hydrocephalus children's executive functioning and the parent ratings of their executive functioning.

RESULTS

Overall, the children with a history of shunted hydrocephalus displayed more executive dysfunction than their healthy peers. These children were rated by their parents as having more executive dysfunction than their healthy peers and displaying working memory, initiation, mental flexibility and self-monitoring difficulties, which appear to increase with age among the shunted hydrocephalus group. While parent ratings as measured by the BRIEF indices did not correlate with all executive tasks within the shunted hydrocephalus group, the cognitive tests assessing mental flexibility may be sensitive to the problems noted by parents at home.

CONCLUSIONS

The children with a history of shunted hydrocephalus displayed executive functioning deficits on formal examination. The parents of children with a history of shunted hydrocephalus report ongoing executive difficulties which may increase with age.

Prospective memory in adults with spina bifida

INTRODUCTION

Individuals with neurodevelopmental disorders have been observed to show accelerated cognitive aging or even dementia as early as 30 and 40 years of age. Memory deficits are an important component of age-related cognitive loss.

METHODS

In this study, we investigated prospective memory, which is often impaired in aging, in a group of 32 adults with spina bifida meningomyelocele (SBM), including members of the oldest living cohort successfully treated with shunts to divert excess cerebrospinal fluid, ventriculomegaly, and hydrocephalus, who are now around 50 years of age. Seventeen typically developing adults provided a comparison group.

RESULTS

The SBM and comparison groups differed in the prospective memory total score as well as in both time-based and event-based subscores. Prospective memory was impaired in both older and younger individuals with SBM. However, the percentage of individuals with impaired or poor prospective memory was three times higher in the older SBM group than in the younger SBM group. The results are considered in relation to specific features of the complex brain reorganization in SBM.

Anomalous development of brain structure and function in spina bifida myelomeningocele

Spina bifida myelomeningocele (SBM) is a specific type of neural tube defect whereby the open neural tube at the level of the spinal cord alters brain development during early stages of gestation. Some structural anomalies are virtually unique to individuals with SBM, including a complex pattern of cerebellar dysplasia known as the Chiari II malformation. Other structural anomalies are not necessarily unique to SBM, including altered development of the corpus callosum and posterior fossa. Within SBM, tremendous heterogeneity is reflected in the degree to which brain structures are atypical in qualitative appearance and quantitative measures of morphometry. Hallmark structural features of SBM include overall reductions in posterior fossa and cerebellum size and volume. Studies of the corpus callosum have shown complex patterns of agenesis or hypoplasia along its rostral-caudal axis, with rostrum and splenium regions particularly susceptible to agenesis. Studies of cortical regions have demonstrated complex patterns of thickening, thinning, and gyrification. Diffusion tensor imaging studies have reported compromised integrity of some specific white matter pathways. Given equally complex ocular motor, motor, and cognitive phenotypes consisting of relative strengths and weaknesses that seem to align with altered structural development, studies of SBM provide new insights to our current understanding of brain structure-function associations.

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.

Cellular damage and prevention in childhood hydrocephalus

The literature concerning brain damage due to hydrocephalus, especially in children and animal models, is reviewed. The following conclusions are reached: 1. Hydrocephalus has a deleterious effect on brain that is dependent on magnitude and duration of ventriculomegaly and modified by the age of onset. 2. Animal models have many histopathological similarities to humans and can be used to understand the pathogenesis of brain damage. 3. Periventricular axons and myelin are the primary targets of injury. The pathogenesis has similarities to traumatic and ischemic white matter injury. Secondary changes in neurons reflect compensation to the stress or ultimately the disconnection. 4. Altered efflux of extracellular fluid could result in accumulation of waste products that might interfere with neuron function. Further research is needed in this as well as the blood-brain barrier in hydrocephalus. 5. Some, but not all, of the changes are preventable by shunting CSF. However, axon loss cannot be reversed, therefore shunting in a given case must be considered carefully. 6. Experimental work has so far failed to show any benefit in reducing CSF production. Pharmacologic protection of the brain, at least as a temporary measure, holds some promise but more pre-clinical research is required.

Chronic hydrocephalus in rats and humans: white matter loss and behavior changes

Chronic hydrocephalus that begins in childhood and progresses only very gradually is sometimes called "arrested" hydrocephalus. Data suggest that this state eventually can become symptomatic and may be treatable by shunting. However, the pathological substrate of the disorder is not entirely understood. We studied chronic hydrocephalus in rats, 9 months after induction by kaolin injection into the cisterna magna, and in humans. In both circumstances, destruction of periventricular white matter structures was worst in those with the largest ventricles. Structures damaged include the corpus callosum, corticospinal tract, and fimbria/fornix projections from the hippocampus. Myelin turnover was increased. These changes were associated with deficits of motor and cognitive function. The cerebral cortex was largely spared. There appears to be a threshold of ventricle size beyond which functional changes manifest, but this undoubtedly is modified by factors such as age of onset and rate of enlargement. These data support the need for persistent follow-up of patients with chronic, apparently stable hydrocephalus. A slight increase in size of already enlarged ventricles might cause significant axonal damage.