The development of pragmatic skills in children after hemispherotomy: Contribution from left and right hemispheres

Insights on cognitive reorganization after hemispherectomy in Rasmussen's encephalitis. A narrative review

Rasmussen's encephalitis is a rare neurological pathology affecting one cerebral hemisphere, therefore, posing unique challenges. Patients may undergo hemispherectomy, a surgical procedure after which cognitive development occurs in the isolated contralateral hemisphere. This rare situation provides an excellent opportunity to evaluate brain plasticity and cognitive recovery at a hemispheric level. This literature review synthesizes the existing body of research on cognitive recovery following hemispherectomy in Rasmussen patients, considering cognitive domains and modulatory factors that influence cognitive outcomes. While language function has traditionally been the focus of postoperative assessments, there is a growing acknowledgment of the need to broaden the scope of language investigation in interaction with other cognitive domains and to consider cognitive scaffolding in development and recovery. By synthesizing findings reported in the literature, we delineate how language functions may find support from the right hemisphere after left hemispherectomy, but also how, beyond language, global cognitive functioning is affected. We highlight the critical influence of several factors on postoperative cognitive outcomes, including the timing of hemispherectomy and the baseline preoperative cognitive status, pointing to early surgical intervention as predictive of better cognitive outcomes. However, further specific studies are needed to confirm this correlation. This review aims to emphasize a better understanding of mechanisms underlying hemispheric specialization and plasticity in humans, which are particularly important for both clinical and research advancements. This narrative review underscores the need for an integrative approach based on cognitive scaffolding to provide a comprehensive understanding of mechanisms underlying the reorganization in Rasmussen patients after hemispherectomy.

Neuropsychological assessment in pediatric epilepsy surgery: A French procedure consensus

Neuropsychological assessment is a mandatory part of the pre- and post-operative evaluation in pediatric epilepsy surgery. The neuropsychology task force of the ILAE - French Chapter aims to define a neuropsychological procedure consensus based on literature review and adapted for French practice. They performed a systematic review of the literature published between 1950 and 2023 on cognitive evaluation of individuals undergoing presurgical work-up and post-surgery follow-up and focused on the pediatric population aged 6-16. They classified publications listed in the PubMed database according to their level of scientific evidence. The systematic literature review revealed no study with high statistical power and only four studies using neuropsychological scales in their French version. Afterwards, the experts defined a neuropsychological consensus strategy in pediatric epilepsy surgery according to the psychometric determinants of cognitive tests, specificity of epilepsy, surgery context, French culture and literature reports. A common French neuropsychological procedure dedicated to pediatric epilepsy surgery is now available. This procedure could serve as a guide for the pre- and post-surgical work-up in French centers with pediatric epilepsy surgery programs. The main goal is to anticipate the functional risks of surgery, to support the postoperative outcome beyond the seizure-related one, while taking into consideration the plasticity and vulnerability of the immature brain and allowing the possibility of collaborative studies.

Relationship of epilepsy on the linguistic-cognitive profile of children with ASD: A systematic review of the literature

Introduction

The prevalence of comorbidity between epilepsy and Autism Spectrum Disorder (ASD) in the pediatric age increased significantly in recent years. The onset of epilepsy negatively influences the abilities of the user with ASD. Thus, epilepsy will be a disabling factor that will reduce the cognitive-linguistic skills of users with ASD. The main objective of this work is to review the current scientific literature and to compare the relationship of epilepsy on the development of cognitive and linguistic skills of children with ASD.

Methods

In this regard, a systematic search was carried out in the main sources (Medline, PubMed, WOS, ResearchGate and Google Scholar). 481 articles were identified, from which, after meeting the different inclusion and exclusion criteria, a total of 18 studies of relevance to the objectives of this work were selected.

Results

The results reflect that, at a global level, epilepsy significantly influences the performance of cognitive- linguistic skills in people with ASD.

Discussion

In conclusion, epilepsy in the ASD population leads to a reduction in cognitive and linguistic abilities, which respond to the different types of epilepsy and their location, significantly impacting the quality of life and basic activities of daily living of the user with ASD.

The hidden face of hemispherectomy: Visuo-spatial and visuo-perceptive processing after left or right functional hemispherectomy in 40 children

Functional hemispherectomy results in good outcomes in cases of refractory epilepsy and constitutes a unique situation in which to study cerebral plasticity and the reorganization of lateralized functions of the brain, especially in cases of infancy or childhood surgery. Previous studies have highlighted the remarkable ability of the brain to recover language after left hemispherectomy. This leads to a reorganization of language networks toward right hemisphere, causing limitation in the development of visuo-spatial abilities, known as a crowding effect in the right hemisphere. Deficits in nonverbal functions have also been described as a more direct consequence of right hemipherectomy, but the results from case studies have sometimes been contradictory. We conducted a group study which may effectively compare patients with left and right hemispherectomy and address the effects of the age of seizure onset and surgery. We analyzed the general visuo-spatial and visuo-perceptive abilities, including face and emotional facial expression processing, in a group of 40 patients aged 7-16 years with left (n = 24) or right (n = 16) functional hemispherectomy. Although the groups did not differ, on average, in general visuo-spatial and visuo-perceptive skills, patients with right hemispherectomy were more impaired in the processing of faces and emotional facial expressions compared with patients with left hemispherectomy. This may reflect a specific deficit in the perceptual processing of faces after right hemispherectomy. Results are discussed in terms of limited plasticity of the left hemisphere for facial and configural processing.

The influencing factors and changes of cognitive function within 40 Rasmussen encephalitis patients that received a hemispherectomy

OBJECTIVE

To evaluate the influencing factors and cognitive functional changes in Rasmussen encephalitis (RE) patients who received a hemispherectomy.

METHODS

Forty RE patients underwent a hemispherectomy with at least a 2 years follow- up were included in this study . Postoperative seizure outcomes were evaluated according to the Engle classification scale. Univariate analysis and a multivariate logistic regression model in a backward fashion were used to identify the potential predictors of cognitive function.

RESULTS

All 40 patients had an Engle classification outcome at a 2 years follow-up. Univariate and multivariate analyses revealed that seizure duration (OR 10.06, 95% CI 1.54-3.85, p = 0.038), age at surgery (OR 3.06, 95% CI 1.21-3.56, p = 0.043), and MRI score (OR 0.09, 95% CI 0.01-0.67 p = 0.024) are associated with postoperative cognitive outcomes respectively. Moreover,  VIQ and PIQ were negatively correlated linearly with duration of seizures and MRI score. Patients with a good VIQ and PIQ before the operation were more likely to have a better VIQ and PIQ postoperatively (p < 0.001 and p < 0.001, respectively). And, operation side is an important factor affecting cognitive function; therefore, a left hemispherectomy has a greater impact on the patient's IQ and language.

CONCLUSIONS

RE patients' cognitive dysfunctions are improved after a hemispherectomy. Right-side operation can achieve better postoperative cognitive outcomes especially in VIQ and language. A shorter duration of seizures, early age at surgery, and less severe brain atrophy suggest better cognitive outcomes after a hemispherectomy.

Hemispherotomy for pediatric epilepsy: a systematic review and critical analysis

PURPOSE

Several variations of functional disconnection surgery have been described for the treatment of lateralized, hemispheric, drug-resistant epilepsy in children. The purpose of this study is to investigate the existing literature regarding patient selection, approach, and outcomes after hemispherotomy.

METHODS

A systematic review of the English literature through February 2019 was performed in accordance with the PRISMA statement. The articles were classified by level of evidence and summarized in an evidentiary table. Seizure outcomes, functional outcomes, surgical techniques, complications, and patient selection were critically analyzed.

RESULTS

A total of 173 papers were reviewed, of which 37 met criteria of inclusion and exclusion. Thirteen studies were classified as level III evidence, the remaining reached level IV. Vertical and lateral hemispherotomy achieve similar rates of seizure freedom and functional outcomes, though parasagittal and interhemispheric approaches may have shorter operative times and less blood loss. Etiology, bilateral MRI abnormalities, and nonlateralizing EEG did not predict worse seizure or functional outcomes.

CONCLUSIONS

Both vertical and lateral hemispherotomy approaches result in durable, reproducible benefits to epilepsy severity and functional status in appropriately selected pediatric patients.

Language after childhood hemispherectomy: A systematic review

OBJECTIVE

To conduct a systematic review on language outcomes after left and right hemispherectomy in childhood, a surgical procedure that involves removing or disconnecting a cerebral hemisphere.

METHODS

We searched MEDLINE, Embase, and PsycInfo for articles published between January 1, 1988, and May 16, 2019. We included (1) all types of observational studies; (2) studies in which hemispherectomy was performed before age 18 years; and (3) studies with standardized scores measuring receptive vocabulary, expressive vocabulary, sentence comprehension, and/or sentence production. We calculated mean z scores after left and right hemispherectomy in the whole group and within etiology-specific subgroups.

RESULTS

Our search identified 1,096 studies, of which 17 were eligible. The cohort added up to 205 individuals (62% left hemispherectomy) assessed 1 to 15 years after surgery. In the left surgery group, all language skills were impaired (z scores <-1.5) except sentence comprehension. In the right surgery group, language performance was in the borderline range (z scores ∼ -1.5). Children with cortical dysplasia showed the worst outcomes irrespective of surgery side (z scores <-2.5). Individuals with left vascular etiology and right-sided Rasmussen syndrome showed the best outcomes.

CONCLUSION

Evidence based on the largest patient cohort to date (205 participants) suggests that the risk of language impairment after hemispherectomy is high, with few exceptions. Etiology plays a major role in postsurgical plasticity. We recommend specialist evaluation of language skills soon after surgery to identify intervention targets. Large-scale studies examining outcomes in consecutive cases are still needed.

Left hemispherectomy in older children and adolescents: outcome of cognitive abilities

PURPOSE

Hemispherectomy is an effective treatment option for pharmacoresistant epilepsy. Nevertheless, when high cortical functions are at risk during the presurgical evaluation, especially for older children, and for the left hemisphere, despite good seizure outcome, the anticipated decrease of cognitive functions may prevent a decision to perform surgery. The objective of this study is to report the cognitive outcome, based on verbal and performance intelligence skills, in a series of older children and adolescents who underwent left hemispherectomy, analyzing the risks (residual cognitive deficit) and benefits (seizure reduction) of surgery.

METHODS

We retrospectively analyzed pre- and postoperative clinical and neuropsychological data from our patients who underwent left hemispherectomy, aged between 6 and 18 years.

RESULTS

We included 15 patients, with a mean follow-up of 3.1 years, 12 patients (80%) were Engel I, and the other three were classified as Engel II, III, and IV. Nine patients were tested by Wechsler Scales of Intelligence; postsurgically all but one kept the same intellectual levels; verbal intelligence quotient (VIQ) remained unchanged in 13 and improved in one, whereas performance intelligence quotient (PIQ) decreased in four patients. Both Total Vineland and communication scores of Vineland Adaptive Behavior Scales were obtained in six patients: in all, scores were classified as deficient adaptive functioning pre- and postoperatively, remaining unchanged.

CONCLUSION

The evaluation of the remaining intellectual abilities after left hemispherectomy in older children and adolescents is useful to discuss the risks and benefits of this surgery, enabling better and safer decisions regarding surgical indications and timing.

The mentalizing network and theory of mind mediate adjustment after childhood traumatic brain injury

Childhood traumatic brain injury (TBI) affects over 600 000 children per year in the United States. Following TBI, children are vulnerable to deficits in psychosocial adjustment and neurocognition, including social cognition, which persist long-term. They are also susceptible to direct and secondary damage to related brain networks. In this study, we examine whether brain morphometry of the mentalizing network (MN) and theory of mind (ToM; one component of social cognition) mediates the effects of TBI on adjustment. Children with severe TBI (n = 15, M_age = 10.32), complicated mild/moderate TBI (n = 30, M_age = 10.81) and orthopedic injury (OI; n = 42, M_age = 10.65) completed measures of ToM and executive function and underwent MRI; parents rated children’s psychosocial adjustment. Children with severe TBI demonstrated reduced right-hemisphere MN volume, and poorer ToM, vs children with OI. Ordinary least-squares path analysis indicated that right-hemisphere MN volume and ToM mediated the association between severe TBI and adjustment. Parallel analyses substituting the central executive network and executive function were not significant, suggesting some model specificity. Children at greatest risk of poor adjustment after TBI could be identified based in part on neuroimaging of social brain networks and assessment of social cognition and thereby more effectively allocate limited intervention resources.

A new model of experimental hemispherotomy in young adult Rattus norvegicus: a neural tract tracing and SPECT in vivo study

OBJECTIVE

The objective of this study was to describe a new experimental model of hemispherotomy performed on laboratory animals.

METHODS

Twenty-six male young adult Wistar rats were distributed into two groups (surgery and control). The nonfluorescent anterograde neurotracer biotinylated dextran amine (BDA; 10,000 MW) was microinjected into the motor cortex area (M1) according to The Rat Brain in Stereotaxic Coordinates atlas to identify pathways and fibers disconnected after the experimental hemispherectomy. SPECT tomographic images of 99mTc hexamethylpropyleneamine oxime were obtained to verify perfusion in functioning areas of the disconnected and intact brain. A reproducible and validated surgical procedure is described in detail, including exact measurements and anatomical relationships. An additional 30 rodents (n = 10 rats per group) were divided into naïve, sham, and hemispherotomy groups and underwent the rotarod test.

RESULTS

Cortico-cortical neural pathways were identified crossing the midline and contacting neuronal perikarya in the contralateral brain hemisphere in controls, but not in animals undergoing hemispherotomy. There was an absence of perfusion in the left side of the brain of the animals undergoing hemispherotomy. Motor performance was significantly affected by brain injuries, increasing the number of attempts to maintain balance on the moving cylinder in the rotarod test at 10 and 30 days after the hemispherotomy, with a tendency to minimize the motor performance deficit over time.

CONCLUSIONS

The present findings show that the technique reproduced neural disconnection with minimal resection of brain parenchyma in young adult rats, thereby duplicating the hemispherotomy procedures in human patients.

Language plasticity after hemispherotomy of the dominant hemisphere in 3 patients: Implication of non-linguistic networks

The neural networks involved in language recovery following hemispherotomy of the dominant hemisphere after language acquisition in children remain poorly known. Twelve hemispherotomized children (mean age at surgery: 11.3years) with comparable post-operative neuropsychological patterns underwent multi-task language functional MRI. Three of them had recovered from an initial postoperative aphasia i.e., hemispherotomy was performed on the language-dominant hemisphere. Our main results revealed (1) perisylvian activations in all patients after either left or right hemispherotomy; (2) no differences in activations between groups regarding the side of hemispherotomy; (3) additional activations in pre-frontal (3/3) and hippocampal/parahippocampal and occipito-parietal (2/3) areas, when comparing language activation in each of the three subjects with hemispherotomy of the language-dominant hemisphere to the group of 9 non-dominant hemispherotomized patients. These neural networks support the stronger engagement of learning and memory during language recovery in a hemisphere that was not initially actively subserving language.

Influence of Aerobic Training and Combinations of Interventions on Cognition and Neuroplasticity after Stroke

Stroke often aggravated age-related cognitive impairments that strongly affect several aspects of quality of life. However, few studies are, to date, focused on rehabilitation strategies that could improve cognition. Among possible interventions, aerobic training is well known to enhance cardiovascular and motor functions but may also induce beneficial effects on cognitive functions. To assess the effectiveness of aerobic training on cognition, it seems necessary to know whether training promotes the neuroplasticity in brain areas involved in cognitive functions. In the present review, we first explore in both human and animal how aerobic training could improve cognition after stroke by highlighting the neuroplasticity mechanisms. Then, we address the potential effect of combinations between aerobic training with other interventions, including resistance exercises and pharmacological treatments. In addition, we postulate that classic recommendations for aerobic training need to be reconsidered to target both cognition and motor recovery because the current guidelines are only focused on cardiovascular and motor recovery. Finally, methodological limitations of training programs and cognitive function assessment are also developed in this review to clarify their effectiveness in stroke patients.