Cognitive assessment in epilepsy surgery of children

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.

Long-term intellectual and developmental outcomes after pediatric epilepsy surgery: A systematic review and meta-analysis

In addition to the primary aim of seizure freedom, a key secondary aim of pediatric epilepsy surgery is to stabilize and, potentially, optimize cognitive development. Although the efficacy of surgical treatment for seizure control has been established, the long-term intellectual and developmental trajectories are yet to be delineated. We conducted a systematic review and meta-analysis of studies reporting pre- and postsurgical intelligence or developmental quotients (IQ/DQ) of children with focal lesional epilepsy aged ≤18 years at epilepsy surgery and assessed at >2 years after surgery. We determined the IQ/DQ change and conducted a random-effects meta-analysis and meta-regression to assess its determinants. We included 15 studies reporting on 341 patients. The weighted mean age at surgery was 7.1 years (range = .3-13.8). The weighted mean postsurgical follow-up duration was 5.6 years (range = 2.7-12.8). The overall estimate of the mean presurgical IQ/DQ was 60 (95% confidence interval [CI] = 47-73), the postsurgical IQ/DQ was 61 (95% CI = 48-73), and the change was +.94 IQ/DQ (95% CI = -1.70 to 3.58, p = .486). Children with presurgical IQ/DQ ≥ 70 showed a tendency for higher gains than those with presurgical IQ/DQ < 70 (p = .059). Higher gains were determined by cessation of antiseizure medication (ASM; p = .041), not just seizure freedom. Our findings indicate, on average, stabilization of intellectual and developmental functioning at long-term follow-up after epilepsy surgery. Once seizure freedom has been achieved, ASM cessation enables the optimization of intellectual and developmental trajectories in affected children.

Clinical and Surgical Approach for Cerebral Cortical Dysplasia

The present article describes pathophysiological and clinical aspects of congenital malformations of the cerebral tissue (cortex and white matter) that cause epilepsy and very frequently require surgical treatment. A particular emphasis is given to focal cortical dysplasias, the most common pathology among these epilepsy-related malformations. Specific radiological and surgical features are also highlighted, so a thorough overview of cortical dysplasias is provided.

A methodological perspective on the cognitive outcome of epilepsy surgery in children and adolescents

PURPOSE

The purpose of the study was to explore the impact of timing and test specificity of cognitive outcome measures after pediatric epilepsy surgery.

METHODS

A consecutive national cohort of 114 children with medically resistant epilepsy having had resective epilepsy surgery were screened for children tested with a complete age-appropriate Wechsler Intelligence test at two or three time-points. This provided 43 children for analyses. Composite subscale scores were assessed in comparison to index and intelligence quotient (IQ) scores.

RESULTS

We found a main effect of time in seizure-free children for full-scale IQ (FSIQ); F(2, 42) = 6.49 with higher T2 measures compared with T1 (M_Diff = 5.46, p = .006). There was a difference in FSIQ scores between seizure-free and nonseizure-free children at T2; M = 7.31, 95% confidence interval (CI) [0.05 to 14.57], t(38) = 2.04, p = .049, favoring seizure-free children. A statistical difference between composite scale scores and index scores was found with medium to large effect. The correlation of medical treatment (anti-epileptic drug (AED)) change and score differences in FSIQ outcome was significant (p = .041), with less AED correlated with a higher FSIQ. All children with left-temporal surgery had a stable or improved verbal comprehension composite subscale score outcome at T2 regardless of seizure status.

CONCLUSION

Our results correspond to some longitudinal studies with outcome measures >2 years, in contrast to short-term studies ≤2 years with a stable outcome. Our study supports the fact that the specificity of the used tests and the timing of assessments after pediatric epilepsy surgery are essential factors for the clinical validity of outcome measures. However, there are further needs of extensive longitudinal studies to provide a better understanding of life-long cognitive development and impact after childhood epilepsy surgery.

Epilepsy surgery for Rasmussen encephalitis: the UCLA experience

OBJECTIVE

Rasmussen encephalitis (RE) is a rare inflammatory neurological disorder typically involving one hemisphere and resulting in drug-resistant epilepsy and progressive neurological decline. Here, the authors present seizure outcomes in children who underwent epilepsy surgery for RE at a single institution.

METHODS

The records of consecutive patients who had undergone epilepsy surgery for RE at the UCLA Mattel Children's Hospital between 1982 and 2018 were retrospectively reviewed. Basic demographic information, seizure history, procedural notes, and postoperative seizure and functional outcome data were analyzed.

RESULTS

The cohort included 44 patients, 41 of whom had sufficient data for analysis. Seizure freedom was achieved in 68%, 48%, and 22% of the patients at 1, 5, and 10 years, respectively. The median time to the first seizure for those who experienced seizure recurrence after surgery was 39 weeks (IQR 11-355 weeks). Anatomical hemispherectomy, as compared to functional hemispherectomy, was independently associated with a longer time to postoperative seizure recurrence (HR 0.078, p = 0.03). There was no statistically significant difference in postoperative seizure recurrence between patients with complete hemispherectomy and those who had less-than-hemispheric surgery. Following surgery, 68% of the patients could ambulate and 84% could speak regardless of operative intervention.

CONCLUSIONS

A large proportion of RE patients will have seizure relapse after surgery, though patients with anatomical hemispherectomies may have a longer time to postoperative seizure recurrence. Overall, the long-term data in this study suggest that hemispheric surgery can be seen as palliative treatment for seizures rather than a cure for RE.

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.

Impact of epilepsy surgery on quality of life and burden of caregivers in children and adolescents

OBJECTIVE

The objective of this study was to analyze the impact of pediatric epilepsy surgery on the quality of life (QOL), determining whether patients improve, worsen, or maintain their preoperative patterns, as it relates to the burden of caregivers, as well as evaluating potential related factors, from both the children and caregivers perspectives.

MATERIAL AND METHODS

This is a retrospective study of children and adolescents who underwent epilepsy surgery and were evaluated through clinical data, videoelectroencephalogram (V-EEG), neuroimaging findings, neuropsychological testing, and aspects of QOL. These assessments were performed prior to surgery and after six months and two years of follow-up. Quality of life was assessed with epilepsy-specialized questionnaires, namely Questionnaire health-related quality of life for children with epilepsy (QVCE-50), Autoquestionnaire Qualité de Vie Enfant Image Scale (AUQUEI), Quality of life in epilepsy inventory for adolescents (QOLEI-AD-48); and burden of caregivers with Burden Interview - ZARIT scale. Postoperative changes in QVCE-50 were quantified using measures of the analysis of variance (ANOVA MR) for comparison of the difference between the three times of the scale and domains.

RESULTS

Fifty patients were enrolled. Of these, 27 (54%) were male, with a mean age at surgery of 8.2 years (range: 1-18 years). Thirty-five patients (70%) were Engel I and one was Engel II (2%) at six months of follow-up, whereas 28 (56%) were Engel I and 32 (64%) were Engel I or II at two years of follow-up. Preoperatively, 21 (42%) presented with moderate or severe intellectual disability. Postoperative cognitive evaluations at the two-year follow-up showed 18 (36%) maintained similar deficits. The QVCE-50 showed postoperative improvement in the two-year follow-up period, but not at six months after surgery. Postoperative improvements were associated mainly with better seizure outcome. Autoperception evaluations were limited because of the clinical and cognitive severity of patients. The burden of caregivers was quoted as mild to moderate and remained unchanged postoperatively.

CONCLUSIONS

Children and adolescents with surgically treated epilepsy reach a good seizure outcome, stabilize in intellectual and adaptive functions, and have an increase in QOL, from the caregiver's perspective. Nevertheless, their burden remains unchanged. Seizure outcome is the main factor for improvement in the QOL. The upgrading of structured questionnaires and QOL instruments specific to pediatric epilepsy can be helpful to assess patient- and caregiver-reported surgical outcomes, allowing for better planning of therapeutic approaches.

Preoperative evaluation and surgical management of infants and toddlers with drug-resistant epilepsy

OBJECTIVE Despite perioperative risks, epilepsy surgery represents a legitimate curative or palliative treatment approach for children with drug-resistant epilepsy (DRE). Several factors characterizing infants and toddlers with DRE create unique challenges regarding optimal evaluation and management. Epilepsy surgery within children < 3 years of age has received moderate attention in the literature, including mainly case series and retrospective studies. This article presents a systematic literature review and explores multidisciplinary considerations for the preoperative evaluation and surgical management of infants and toddlers with DRE. METHODS The study team conducted a systematic literature review based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, targeting studies that investigated children < 3 years of age undergoing surgical treatment of DRE. Using the PubMed database, investigators selected peer-reviewed articles that reported seizure outcomes with or without developmental outcomes and/or perioperative complications. Studies were eliminated based on the following exclusion criteria: sample size < 5 patients; and inclusion of patients > 3 years of age, when demographic and outcomes data could not be separated from the cohort of patients < 3 years of age. RESULTS The study team identified 20 studies published between January 1990 and May 2017 that satisfied eligibility criteria. All selected studies represented retrospective reviews, observational studies, and uncontrolled case series. The compiled group of studies incorporated 465 patients who underwent resective or disconnective surgery (18 studies, 444 patients) or vagus nerve stimulator insertion (2 studies, 21 patients). Patient age at surgery ranged between 28 days and 36 months, with a mean of 16.8 months (1.4 years). DISCUSSION The study team provided a detailed summary of the literature review, focusing on the etiologies, preoperative evaluation, surgical treatments, seizure and developmental outcomes, and potential for functional recovery of infants and toddlers with DRE. Additionally, the authors discussed special considerations in this vulnerable age group from the perspective of multiple disciplines. CONCLUSIONS While presenting notable challenges, pediatric epilepsy surgery within infants and toddlers (children < 3 years of age) offers significant opportunities for improved seizure frequency, neuro-cognitive development, and quality of life. Successful evaluation and treatment of young children with DRE requires special consideration of multiple aspects related to neurological and physiological immaturity and surgical morbidity.

Surgery for epilepsy

BACKGROUND

This is an updated version of the original Cochrane review, published in 2015.Focal epilepsies are caused by a malfunction of nerve cells localised in one part of one cerebral hemisphere. In studies, estimates of the number of individuals with focal epilepsy who do not become seizure-free despite optimal drug therapy vary between at least 20% and up to 70%. If the epileptogenic zone can be located, surgical resection offers the chance of a cure with a corresponding increase in quality of life.

OBJECTIVES

The primary objective is to assess the overall outcome of epilepsy surgery according to evidence from randomised controlled trials.Secondary objectives are to assess the overall outcome of epilepsy surgery according to non-randomised evidence, and to identify the factors that correlate with remission of seizures postoperatively.

SEARCH METHODS

For the latest update, we searched the following databases on 11 March 2019: Cochrane Register of Studies (CRS Web), which includes the Cochrane Epilepsy Group Specialized Register and the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid, 1946 to March 08, 2019), ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP).

SELECTION CRITERIA

Eligible studies were randomised controlled trials (RCTs) that included at least 30 participants in a well-defined population (age, sex, seizure type/frequency, duration of epilepsy, aetiology, magnetic resonance imaging (MRI) diagnosis, surgical findings), with an MRI performed in at least 90% of cases and an expected duration of follow-up of at least one year, and reporting an outcome related to postoperative seizure control. Cohort studies or case series were included in the previous version of this review.

DATA COLLECTION AND ANALYSIS

Three groups of two review authors independently screened all references for eligibility, assessed study quality and risk of bias, and extracted data. Outcomes were proportions of participants achieving a good outcome according to the presence or absence of each prognostic factor of interest. We intended to combine data with risk ratios (RRs) and 95% confidence intervals (95% CIs).

MAIN RESULTS

We identified 182 studies with a total of 16,855 included participants investigating outcomes of surgery for epilepsy. Nine studies were RCTs (including two that randomised participants to surgery or medical treatment (99 participants included in the two trials received medical treatment)). Risk of bias in these RCTs was unclear or high. Most of the remaining 173 non-randomised studies followed a retrospective design. We assessed study quality using the Effective Public Health Practice Project (EPHPP) tool and determined that most studies provided moderate or weak evidence. For 29 studies reporting multivariate analyses, we used the Quality in Prognostic Studies (QUIPS) tool and determined that very few studies were at low risk of bias across domains.In terms of freedom from seizures, two RCTs found surgery (n = 97) to be superior to medical treatment (n = 99); four found no statistically significant differences between anterior temporal lobectomy (ATL) with or without corpus callosotomy (n = 60), between subtemporal or transsylvian approach to selective amygdalohippocampectomy (SAH) (n = 47); between ATL, SAH and parahippocampectomy (n = 43) or between 2.5 cm and 3.5 cm ATL resection (n = 207). One RCT found total hippocampectomy to be superior to partial hippocampectomy (n = 70) and one found ATL to be superior to stereotactic radiosurgery (n = 58); and another provided data to show that for Lennox-Gastaut syndrome, no significant differences in seizure outcomes were evident between those treated with resection of the epileptogenic zone and those treated with resection of the epileptogenic zone plus corpus callosotomy (n = 43). We judged evidence from the nine RCTs to be of moderate to very low quality due to lack of information reported about the randomised trial design and the restricted study populations.Of the 16,756 participants included in this review who underwent a surgical procedure, 10,696 (64%) achieved a good outcome from surgery; this ranged across studies from 13.5% to 92.5%. Overall, we found the quality of data in relation to recording of adverse events to be very poor.In total, 120 studies examined between one and eight prognostic factors in univariate analysis. We found the following prognostic factors to be associated with a better post-surgical seizure outcome: abnormal pre-operative MRI, no use of intracranial monitoring, complete surgical resection, presence of mesial temporal sclerosis, concordance of pre-operative MRI and electroencephalography, history of febrile seizures, absence of focal cortical dysplasia/malformation of cortical development, presence of tumour, right-sided resection, and presence of unilateral interictal spikes. We found no evidence that history of head injury, presence of encephalomalacia, presence of vascular malformation, and presence of postoperative discharges were prognostic factors of outcome.Twenty-nine studies reported multi-variable models of prognostic factors, and showed that the direction of association of factors with outcomes was generally the same as that found in univariate analyses.We observed variability in many of our analyses, likely due to small study sizes with unbalanced group sizes and variation in the definition of seizure outcome, the definition of prognostic factors, and the influence of the site of surgery AUTHORS' CONCLUSIONS: Study design issues and limited information presented in the included studies mean that our results provide limited evidence to aid patient selection for surgery and prediction of likely surgical outcomes. Future research should be of high quality, follow a prospective design, be appropriately powered, and focus on specific issues related to diagnostic tools, the site-specific surgical approach, and other issues such as extent of resection. Researchers should investigate prognostic factors related to the outcome of surgery via multi-variable statistical regression modelling, where variables are selected for modelling according to clinical relevance, and all numerical results of the prognostic models are fully reported. Journal editors should not accept papers for which study authors did not record adverse events from a medical intervention. Researchers have achieved improvements in cancer care over the past three to four decades by answering well-defined questions through the conduct of focused RCTs in a step-wise fashion. The same approach to surgery for epilepsy is required.

Long term neurocognitive improvement after "late" right hemispherectomy: case report and review of the literature

OBJECTIVE

To study the long-term neurocognitive changes of a right-handed girl with intractable epilepsy after late right hemispherectomy and compare them with data in the literature.

METHOD

The girl was affected by an epileptic encephalopathy associated with right fronto-temporo-parietal polymicrogyria; she was submitted to right hemispherectomy at the age of 5 and examined with cognitive and neuropsychological tests at the age of 17 years. The girl took advantage of neurocognitive rehabilitation for several years; she is currently seizure-free and off therapy.

RESULTS

At the end of the follow-up, the full-scale IQ is stable and within the normal range (p = 88). As the discrepancy between verbal IQ (pp = 120) and performance IQ (pp = 71) is significantly high, the girl was subjected to neurocognitive evaluation with the following results: verbal problem solving, verbal short- and long-term memory, and executive functions are within normal range. The most fragile functional areas are visual and spatial reasoning, verbal working memory, short-term visuospatial memory, visual attention, and processing speed, all > 2 SD. The spatial tests, such as coding, matrix reasoning, picture concepts, and arithmetic reasoning (which are favored by other functions such as associative memory and learning ability), are less severely impaired.

CONCLUSIONS

These findings show that good conceptual skills and verbal reasoning can compensate for some deficits in visual-perceptual and visuospatial functions.

Academic Outcomes in Individuals With Childhood-Onset Epilepsy: Mediating Effects of Working Memory

OBJECTIVES

Academic difficulties are common in children with epilepsy, although little is known about the effect of various seizure-related and cognitive variables. Given that persistent seizures may negatively impact academics, and that working memory is predictive of academic abilities, we examined the effects of recent seizures and working memory on word reading, spelling, and arithmetic in pediatric epilepsy. We hypothesized that persistent seizures would be associated with lower working memory ability, which would in turn result in poorer academic performance.

METHODS

Our sample consisted of 91 children with epilepsy being treated at the Hospital for Sick Children in Toronto, Canada, who underwent neuropsychological testing between 2002 and 2009 to help determine surgical candidacy. Four to 11 years later, follow-up testing was conducted on both surgical (n=61) and non-surgical (n=30) patients. Seizure status was defined by the presence or absence of seizures within the preceding 12 months.

RESULTS

5000 bias-corrected bootstrap resamples with replacement were used to calculate the 95% confidence intervals (CIs) for the indirect effect of seizure status on academics through working memory, controlling for baseline academic functioning. Persistent seizures were associated with reduced working memory, which was in turn associated with lower reading (B=-4.64, 95% CI [-10.21, -1.30]), spelling (B=-7.09, 95% CI [-13.97, -2.56], and arithmetic scores (B=-8.04, 95% CI [-13.66, -3.58] at follow-up.

CONCLUSIONS

For children with intractable epilepsy, working memory deficits present a significant barrier to the development of academic skills. Working memory interventions may be a helpful adjunct to academic remediation in this population to facilitate academic progress. (JINS, 2017, 23, 594-604).

Five-Year Long-Term Prognosis of Epileptic Children After Hemispheric Surgery: A Systematic Review and Meta-analysis

To estimate children's long-term seizure outcomes after hemispheric surgery and the associated predictors.A systematic review of 4 databases and a meta-analysis were performed from January 1, 1995 to August 31, 2015. The databases included PubMed, Embase, Science Direct, and Web of Science; patients were classified into the Engel Class I group and the Engel Class II to IV group, according to their seizure outcomes. Nine potential predictors were then stratified across the groups and estimated using the Wilcoxon rank-sum test for continuous variables and the Chi-squared test for categorical variables.The search yielded 15 retrospective studies, with a total sample size of 380. Five years after surgery, 268 (0.71, 95% confidence interval [CI]: 0.64-0.78) children were seizure free; the seizure onset age in the Engel Class I group was significantly higher than that of the Engel Class II to IV group (standardized mean difference [SMD] = 0.26, 95% CI: 0.03-0.49, P = 0.028); specifically, when predicting the positive long-term outcomes, the odds ratio for late onset age (≥3.6 months, median value of the Engel Class II-IV group) versus early onset age was 2.65 (95% CI: 1.454-4.836, z = 3.18, P = 0.001). The abnormal magnetic resonance imaging (MRI) findings were more predictive for positive seizure outcomes than the normal findings (odds ratio [OR] = 4.60, 95% CI: 1.27-16.62, P = 0.02).Following hemispheric surgery, the long-term prognosis of children with epilepsy was good. Late seizure onset (age ≥ 3.6 months) and abnormal MRI findings were positive predictors for long-term seizure control in children.

Cerebral Reorganization after Hemispherectomy: A DTI Study

BACKGROUND AND PURPOSE

Hemispherectomy is a neurosurgical procedure to treat children with intractable seizures. Postsurgical improvement of cognitive and behavioral functions is observed in children after hemispherectomy suggesting plastic reorganization of the brain. Our aim was to characterize changes in DTI scalars in WM tracts of the remaining hemisphere in children after hemispherectomy, assess the associations between WM DTI scalars and age at the operation and time since the operation, and evaluate the changes in GM fractional anisotropy values in patients compared with controls.

MATERIALS AND METHODS

Patients with congenital or acquired neurologic diseases who required hemispherectomy and had high-quality postsurgical DTI data available were included in this study. Atlas- and voxel-based analyses of DTI raw data of the remaining hemisphere were performed. Fractional anisotropy and mean, axial, and radial diffusivity values were calculated for WM and GM regions. A linear regression model was used for correlation between DTI scalars and age at and time since the operation.

RESULTS

Nineteen patients after hemispherectomy and 21 controls were included. In patients, a decrease in fractional anisotropy and axial diffusivity values and an increase in mean diffusivity and radial diffusivity values of WM regions were observed compared with controls (P < .05, corrected for multiple comparisons). In patients with acquired pathologies, time since the operation had a significant positive correlation with white matter fractional anisotropy values. In all patients, an increase in cortical GM fractional anisotropy values was found compared with controls (P < .05).

CONCLUSIONS

Changes in DTI metrics likely reflect Wallerian and/or transneuronal degeneration of the WM tracts within the remaining hemisphere. In patients with acquired pathologies, postsurgical fractional anisotropy values correlated positively with elapsed time since the operation, suggesting a higher ability to recover compared with patients with congenital pathologies leading to hemispherectomy.

Development of intelligence 4 to 11 years after paediatric epilepsy surgery

OBJECTIVE

Little is known about the long-term intellectual outcomes following paediatric epilepsy surgery. Change is not likely within the first 2 years following surgery, and the few studies of longer term outcomes have yielded inconsistent results. This study addressed this issue by examining a large group of surgical and non-surgical patients at baseline and after 4-11 years.

METHODS

Participants were 97 patients (mean age 20.08 [SD: 4.44] years) with childhood-onset intractable epilepsy; 61 had undergone resective epilepsy surgery. Participants underwent neuropsychological testing with the age-appropriate Wechsler Intelligence Scale, generating Full Scale, Performance and Verbal IQs, and Working Memory and Processing Speed indices.

RESULTS

In total 54% of the surgical and 39% of the non-surgical patients were seizure free in the preceding 12 months (p > .05); however, surgical patients did achieve seizure freedom sooner and used fewer medications at follow-up. Surgical status was not associated with any cognitive domain. However, with the exception of processing speed, significant seizure status × time interaction effects were evident and seizure-free patients had higher scores at follow-up. Regression analyses additionally showed that low pre-operative scores were predictive of improvement overtime, whereas high pre-operative scores were predictive of high scores at follow-up.

INTERPRETATION

The results show similar intellectual outcomes for surgical and non-surgical paediatric patients. Four to 11 years after paediatric epilepsy surgery, seizure freedom, whether attained through epilepsy surgery or other means, was found to be associated with intellectual improvements. Seizure status and baseline scores were the most consistent predictors.

Surgery for epilepsy

BACKGROUND

Focal epilepsies are caused by a malfunction of nerve cells localised in one part of one cerebral hemisphere. In studies, estimates of the number of individuals with focal epilepsy who do not become seizure-free despite optimal drug therapy vary according to the age of the participants and which focal epilepsies are included, but have been reported as at least 20% and in some studies up to 70%. If the epileptogenic zone can be located surgical resection offers the chance of a cure with a corresponding increase in quality of life.

OBJECTIVES

The primary objective is to assess the overall outcome of epilepsy surgery according to evidence from randomised controlled trials.The secondary objectives are to assess the overall outcome of epilepsy surgery according to non-randomised evidence and to identify the factors that correlate to remission of seizures postoperatively.

SEARCH METHODS

We searched the Cochrane Epilepsy Group Specialised Register (June 2013), the Cochrane Central Register of Controlled Trials (CENTRAL 2013, Issue 6), MEDLINE (Ovid) (2001 to 4 July 2013), ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) for relevant trials up to 4 July 2013.

SELECTION CRITERIA

Eligible studies were randomised controlled trials (RCTs), cohort studies or case series, with either a prospective and/or retrospective design, including at least 30 participants, a well-defined population (age, sex, seizure type/frequency, duration of epilepsy, aetiology, magnetic resonance imaging (MRI) diagnosis, surgical findings), an MRI performed in at least 90% of cases and an expected duration of follow-up of at least one year, and reporting an outcome relating to postoperative seizure control.

DATA COLLECTION AND ANALYSIS

Three groups of two review authors independently screened all references for eligibility, assessed study quality and risk of bias, and extracted data. Outcomes were proportion of participants achieving a good outcome according to the presence or absence of each prognostic factor of interest. We intended to combine data with risk ratios (RR) and 95% confidence intervals.

MAIN RESULTS

We identified 177 studies (16,253 participants) investigating the outcome of surgery for epilepsy. Four studies were RCTs (including one that randomised participants to surgery or medical treatment). The risk of bias in the RCTs was unclear or high, limiting our confidence in the evidence that addressed the primary review objective. Most of the remaining 173 non-randomised studies had a retrospective design; they were of variable size, were conducted in a range of countries, recruited a wide demographic range of participants, used a wide range of surgical techniques and used different scales used to measure outcomes. We performed quality assessment using the Effective Public Health Practice Project (EPHPP) tool and determined that most studies provided moderate or weak evidence. For 29 studies reporting multivariate analyses we used the Quality in Prognostic Studies (QUIPS) tool and determined that very few studies were at low risk of bias across the domains.In terms of freedom from seizures, one RCT found surgery to be superior to medical treatment, two RCTs found no statistically significant difference between anterior temporal lobectomy (ATL) with or without corpus callosotomy or between 2.5 cm or 3.5 cm ATL resection, and one RCT found total hippocampectomy to be superior to partial hippocampectomy. We judged the evidence from the four RCTs to be of moderate to very low quality due to the lack of information reported about the randomised trial design and the restricted study populations.Of the 16,253 participants included in this review, 10,518 (65%) achieved a good outcome from surgery; this ranged across studies from 13.5% to 92.5%. Overall, we found the quality of data in relation to the recording of adverse events to be very poor.In total, 118 studies examined between one and eight prognostic factors in univariate analysis. We found the following prognostic factors to be associated with a better post-surgical seizure outcome: an abnormal pre-operative MRI, no use of intracranial monitoring, complete surgical resection, presence of mesial temporal sclerosis, concordance of pre-operative MRI and electroencephalography (EEG), history of febrile seizures, absence of focal cortical dysplasia/malformation of cortical development, presence of tumour, right-sided resection and presence of unilateral interictal spikes. We found no evidence that history of head injury, presence of encephalomalacia, presence of vascular malformation or presence of postoperative discharges were prognostic factors of outcome. We observed variability between studies for many of our analyses, likely due to the small study sizes with unbalanced group sizes, variation in the definition of seizure outcome, definition of the prognostic factor and the influence of the site of surgery, all of which we observed to be related to postoperative seizure outcome. Twenty-nine studies reported multivariable models of prognostic factors and the direction of association of factors with outcome was generally the same as found in the univariate analyses. However, due to the different multivariable analysis approaches and selective reporting of results, meaningful comparison of multivariate analysis with univariate meta-analysis is difficult.

AUTHORS' CONCLUSIONS

The study design issues and limited information presented in the included studies mean that our results provide limited evidence to aid patient selection for surgery and prediction of likely surgical outcome. Future research should be of high quality, have a prospective design, be appropriately powered and focus on specific issues related to diagnostic tools, the site-specific surgical approach and other issues such as the extent of resection. Prognostic factors related to the outcome of surgery should be investigated via multivariable statistical regression modelling, where variables are selected for modelling according to clinical relevance and all numerical results of the prognostic models are fully reported. Protocols should include pre- and postoperative measures of speech and language function, cognition and social functioning along with a mental state assessment. Journal editors should not accept papers where adverse events from a medical intervention are not recorded. Improvements in the development of cancer care over the past three to four decades have been achieved by answering well-defined questions through the conduct of focused RCTs in a step-wise fashion. The same approach to surgery for epilepsy is required.

Surgery for posterior quadrantic cortical dysplasia. A review

BACKGROUND

Posterior quadrant dysplastic lesions represent 3-15 % of multilobar cortical developmental pathologies, 3-5 % of all the indications to surgery for epilepsy resistant to medical treatment.

OBJECTIVE AND METHODS

The objective of this study is to review the pertinent literature related to the presurgical clinical, neurophysiological, and neuroradiological evaluation of children affected by posterior quadrant dysplasia in order to discuss the intraoperative management and the different surgical techniques that have been proposed to treat this condition as well as factors related with postsurgical seizure outcome.

RESULTS AND CONCLUSIONS

Seizures appear most commonly in infants and rapidly progress to a catastrophic course. They are mostly represented by focal seizures and spasms. Surface interictal video-EEG is characterized by background flattening and paroxysmal discharges prevalent on the affected side but not unusually extending to the controlateral hemisphere. The last occasionally shows an independent irritative activity in spite of the absence of further visible structural abnormalities. Most of the patients have visual field or visual attention deficits at diagnosis. Resective as well as disconnective surgical procedures have been proposed for the management of this condition, none of them having shown clear advantages in terms of seizure outcome and complications. Intraoperative electrocorticography (EcoG) and sensorimotor monitoring have been successfully used to improve the localization of the epileptic focus and reduce surgical complication rates. Undistincted lesion borders, independent controlateral ictal or/and interictal EEG activity, and incomplete resections/disconnections are among the main factors that have resulted to be associated with a worse seizure outcome.

Fifty consecutive hemispherectomies: outcomes, evolution of technique, complications, and lessons learned

BACKGROUND

Techniques for achieving hemispheric disconnection in patients with epilepsy continue to evolve.

OBJECTIVE

To review the outcomes of the first 50 hemispherectomy surgeries performed by a single surgeon with an emphasis on outcomes, complications, and how these results led to changes in practice.

METHODS

The first 50 hemispherectomy cases performed by the lead author were identified from a prospectively maintained database. Patient demographics, surgical details, clinical outcomes, and complications were critically reviewed.

RESULTS

From 2004 to 2012, 50 patients underwent hemispherectomy surgery (mean follow-up time, 3.5 years). Modified lateral hemispherotomy became the preferred technique and was performed on 44 patients. Forty patients (80%) achieved complete seizure freedom (Engel I). Presurgical and postsurgical neuropsychological evaluations demonstrated cognitive stability. Two cases were performed for palliation only. Previous hemispherectomy surgery was associated with worsened seizure outcome (2 of 6 seizure free; P .005). The use of Avitene was associated with a higher incidence of postoperative hydrocephalus (56% vs 18%; P = .03). In modified lateral hemispherotomy patients without the use of Avitene, the incidence of hydrocephalus was 13%. Complications included infection (n = 3), incomplete disconnection requiring reoperation (n = 1), reversible ischemic neurological deficit (n = 1), and craniosynostosis (n = 1). There were no (unanticipated) permanent neurological deficits or deaths. Minor technique modifications were made in response to specific complications.

CONCLUSION

The modified lateral hemispherotomy is effective and safe for both initial and revision hemispherectomy surgery. Avitene use appears to result in a greater incidence of postoperative hydrocephalus.

Hemispherectomy in the treatment of seizures: a review

The term hemispherectomy refers to the complete removal or functional disconnection of a cerebral hemisphere. The technique was initially developed over 85 years ago to treat infiltrating brain tumors but is now used exclusively for medically refractory epilepsy. Hemispherectomy surgery has progressed from an extremely morbid procedure fraught with complications to a fairly routine one performed at most pediatric epilepsy centers with relatively low risk and great efficacy. The author reviews the history and evolution of hemispherectomy surgery, the relevant pathological conditions, as well as outcomes and complications.

Cognitive outcome after epilepsy surgery in children

The ultimate goal of epilepsy surgery in young children is to stop seizures, interrupt the downhill course of the epileptic encephalopathy, and improve developmental capacities. Postoperative outcome after childhood epilepsy surgery should therefore not only be expressed in terms of seizure freedom, cognitive outcome is an equally important outcome measure. Insight in the mutually dependent variables that can determine pre and postoperative cognitive developmental abilities will improve prediction of outcome and presurgical counseling of parents. The purpose of this review is to discuss the literature regarding cognitive outcome and the predictors of postoperative cognitive functioning after epilepsy surgery in children, particularly those with "catastrophic" epilepsy. There are only few studies in which the relation between possible determinants and cognitive outcome or change was statistically tested in a multivariable manner. Duration of epilepsy, presurgical Developmental Quotient (DQ) or Intelligence Quotient (IQ), and postoperative seizure freedom were the only factors reported in different studies to be independently related to eventual cognitive outcome after epilepsy surgery. Underlying etiology, gender, age at surgery, presurgical DQ/IQ, postoperative seizure freedom, cessation of antiepileptic medication, and follow-up interval have all been described in different surgical cohorts to be independently related to a postoperative change of IQ or DQ scores. To appreciate how each of the pre-epileptic, presurgical, and postoperative variables may independently influence eventual cognitive outcome and postoperative cognitive improvement, we need multicenter studies with large homogenous surgical populations, using standardized tests and multivariable analyses.

Visual cognitive function in infants with intractable epilepsy before and after surgery

PURPOSE

One purpose of pediatric epilepsy surgery is to improve psychomotor development. However, few methods are available for evaluating cognitive function in infants with severe developmental delays. We used the following battery of tests to evaluate visual cognitive function of infants following surgery for intractable epilepsy.

METHODS

The following battery of tests were used to evaluate eight patients before and 1 month after surgery: (1) Erhardt Developmental Vision Assessment (EDVA); (2) evaluation of ocular pursuit for a flashing LED toy; (3) three visual acuity tests preferential looking procedure, optokinetic nystagmus, and Sheridan's Test for Young Children and Retarded balls vision test; and (4) existing developmental test.

RESULTS

EDVA scores and ocular pursuit score with a flashing LED toy showed the same trends with developmental age as the existing developmental tests. However, in some patients, the EDVA score and ocular pursuit score improved greatly, whereas the developmental age changed very little.

CONCLUSIONS

These tests are suitable for patients with intractable epilepsy and severe developmental delay. By performing these tests before and after surgery, small cognitive changes occurring soon after the surgery may be detected.

fMRI and DTI assessment of patients undergoing radical epilepsy surgery

Hemispherectomy is effective for young patients suffered from unilateral cortical disease and severe drug-resistant epilepsy, but a major concern for hemispherectomy is the remaining brain functions and function recovery in patients after such surgery. In this study, seven patients were evaluated with clinical and imaging assessment pre- and post-surgery. Among them, four underwent anatomic hemispherectomy (AH) and three underwent subtotal hemispherectomy (functional hemispherectomy, FH). After the surgery, 71.4% (5/7) patients [(4/4) with AH and (1/3) with FH] became seizure free (Engel class I). Motor function of the paretic upper extremity unchanged in 4 patients and deteriorated in 3. Functional imaging results indicated that relocation of hand motor function (to the ipsilateral hemisphere) could take place before or after the surgery, or did not occur. Similar observations were made in the motor cortex activation on the paretic foot movement. In addition, both the affected and unaffected hemispheres underwent post-surgical changes in the corticospinal tracks (CST) in various degrees, but significant reinforcement of the CST in the remaining unaffected hemisphere was not evident. Further research is needed to reveal the true functional and structural changes of the remaining brain after surgery and to explore the mechanisms of such functional relocation and reorganization in patients underwent hemispherectomy.

Cognitive development from two to ten years after pediatric epilepsy surgery

The development of cognitive functions and the sustainability of seizure control between two and ten years after epilepsy surgery were prospectively investigated in 17 children and adolescents. Intelligence quotient remained stable. Learning capacity improved. Verbal memory improved in half of the subjects and declined in half, whereas figurative memory declined in most patients. Working memory improved as did attention regarding sustained attention and impulse control. In contrast, reaction times were longer, and the auditory attention span was shorter. Executive functions were not affected. Six subjects (35%) were seizure free at the 10-year follow-up, and a seizure reduction of more than 75% had been achieved in 13 (76%). Seizure control improved in five and seizures recurred in two subjects between the two- and the 10-year follow-up.

Paediatric intractable epilepsy syndromes: changing concepts in diagnosis and management

Epilepsy surgery for drug-resistant childhood epilepsy is not new. However, brain imaging, surgical and anaesthetic techniques have improved to the extent that they are now as much safer and realistic option than they were in the past. Further, the range of surgical candidates is wide, and previous concepts about likely surgical candidates are now challenged as children with previously thought widespread or apparent multifocal disease are evaluated. Outcomes for seizure freedom range from 40 to 80 % depending on the underlying aetiology and the extent of resection. However, the aims of surgery may include seizure reduction in some and improvement in neurodevelopment and behaviour in others, which are less -predictable. Epilepsy surgery in children is no longer a last resort. Children thought to be likely candidates should be evaluated early in their natural history to optimise outcomes in the long term.

Tailored resections for intractable rolandic cortex epilepsy in children: a single-center experience with 48 consecutive cases

OBJECTIVE

A single-center experience with pediatric patients who underwent surgery for intractable rolandic epilepsy was reviewed with the aim of identifying putative factors that could influence postoperative seizure outcome in this population.

METHODS

Clinical data of 48 patients under 18 years of age with diagnosis of intractable rolandic epilepsy who underwent surgery from January 1996 to September 2009 were reviewed.

RESULTS

Patients' mean age at surgery was 9.9 ± 5.3 years; mean age at epilepsy onset was 3.9 years; mean seizure duration prior to surgery was 6 years; and mean follow-up was 5.1 years. The most frequent etiologies were cortical dysplasia, astrogliosis, tumors, tuberous sclerosis complex, and Sturge-Weber syndrome, which were observed in 20/48 (41.6%), 10/48 (20.8%), 10/48 (20.8%), 5/48 (10.4%), and 3/48 (6.2%) of the patients, respectively. After surgery, 20 patients (41.6%) showed neurological deficits, which in turn recovered within no longer than 6 months after surgery. Seizure outcome was classified as Engel class I in 29 (60.4%), Engel class II in 10 (20.8%), and Engel class III in 9 (18.8%) of the patients. The factors significantly related with seizure outcome were histological features (tumor versus non-tumor cases, p = 0.04) and lesion site (focal lesions versus non-focal lesions, p = 0.04).

CONCLUSIONS

Tailored resection of rolandic cortex for intractable epilepsy can be safely performed in children. Accurate mapping of both functional cortex and epileptogenic areas may lead to improved seizure outcome. Tumor as well as focal lesions in hand and face motor areas are associated with good seizure outcome.

Cognitive changes following surgery in intractable hemispheric and sub-hemispheric pediatric epilepsy

OBJECTIVES

The objectives were to study the short and longitudinal changes in the cognitive skills of children with intractable epilepsy after hemispheric/sub-hemispheric epilepsy surgery.

METHODS

Sixteen patients underwent surgery from September 2005 until March 2009. They underwent detailed presurgical evaluation of their cognitive skills and were repeated annually for 3 years.

RESULTS

Their mean age was 6.6 years. Epilepsy was due to Rasmussen's encephalitis (n = 9), Infantile hemiplegia seizure syndrome (n = 2), hemimegalencephaly (n = 2), and Sturge Weber syndrome (n = 3). Fourteen (87.5%) patients underwent peri-insular hemispherotomy and two (12.5%) underwent peri-insular posterior quadrantectomy. The mental and social age, gross motor, fine motor, adaptive, and personal social skills showed a steady increase after surgery (p < 0.05). Language showed positive gains irrespective of the side and etiology of the lesion (p = 0.003). However, intelligence quotient (IQ) remained static on follow-up. Patients with acquired pathology gained more in their mental age, language, and conceptual thinking. Age of seizure onset and duration of seizures prior to surgery were predictive variables of postoperative cognitive skills.

CONCLUSIONS

There are short- and long-term gains in the cognitive skills of children with intractable epilepsy after hemispherotomy and posterior quadrantectomy that was better in those patients with acquired diseases. Age of seizure onset and duration of seizures prior to surgery were independent variables that predicted the postoperative outcome.

Reversible acquired epileptic frontal syndrome and CSWS suppression in a child with congenital hemiparesis treated by hemispherotomy

A boy with a right congenital hemiparesis due to a left pre-natal middle cerebral artery infarct developed focal epilepsy at 33 months and then an insidious and subsequently more rapid, massive cognitive and behavioural regression with a frontal syndrome between the ages of 4 and 5 years with continuous spike-waves during sleep (CSWS) on the EEG. Both the epilepsy and the CSWS were immediately suppressed by hemispherotomy at the age of 5 years and 4 months. A behavioural-cognitive follow-up prior to hemispherotomy, an per-operative EEG and corticography and serial post-operative neuropsychological assessments were performed until the age of 11 years. The spread of the epileptic activity to the "healthy" frontal region was the cause of the reversible frontal syndrome. A later gradual long-term but incomplete cognitive recovery, with moderate mental disability was documented. This outcome is probably explained by another facet of the epilepsy, namely the structural effects of prolonged epileptic discharges in rapidly developing cerebral networks which are, at the same time undergoing the reorganization imposed by a unilateral early hemispheric lesion. Group studies on the outcome of children before and after hemispherectomy using only single IQ measures, pre- and post-operatively, may miss particular epileptic cognitive dysfunctions as they are likely to be different from case to case. Such detailed and rarely available complementary clinical and EEG data obtained in a single case at different time periods in relation to the epilepsy, including per-operative electrophysiological findings, may help to understand the different cognitive deficits and recovery profiles and the limits of full cognitive recovery.

Comparative role of neuropsychological testing in the presurgical evaluation of children with medically intractable epilepsies

PURPOSE

In the present study, we evaluated the preoperative demographic, clinical, and neuropsychological variables that could predict postoperative seizure outcome in a group of pediatric epileptic patients.

MATERIALS AND METHODS

We studied 40 consecutive pediatric patients, ages ranging from 6 to 16 years, that underwent resective surgery for the treatment of medically intractable epilepsy at the Clinical Hospital of Ribeirão Preto School of Medicine. We performed ictal electroencephalography (EEG), interictal EEG, magnetic resonance imaging (MRI), and a preoperative neuropsychological assessment in the presurgical workup.

RESULTS

The following factors were correlated with seizure outcome: (1) duration of epilepsy, (2) surgery localization, (3) localized Neuropsychological (NPS) Evaluation, (4) ictal EEG, (5) interictal EEG, and (6) MRI. Mental retardation, NPS tests, and the other demographic variables failed to correlate with seizure reduction.

CONCLUSIONS

The identification of predictor variables of epilepsy surgery outcome could improve the epileptic prognosis and guarantee the children's full potential development.

Approach to pediatric epilepsy surgery: State of the art, Part I: General principles and presurgical workup

In 1990, the National Institute of Health adopted epilepsy surgery in children as an option when medications fail. In the past few years several concepts have become increasingly recognized as key to a successful approach to epilepsy surgery in children. These include the concepts of neuronal plasticity, the epileptogenic lesion, the ictal onset, symptomatogenic, irritative, and epileptogenic zones. In addition, several techniques have increasingly been utilized to delineate the above areas in an attempt to determine, in each patient, the epileptogenic zone, defined as the zone the resection of which leads to seizure freedom. When seizure semiology (which defines the symptomatogenic zone), ictal EEG (which identifies the ictal onset zone), and structural imaging (which identifies the epileptogenic lesion) can be reconciled to infer the location of the epileptogenic zone, surgery is usually, subsequently, undertaken. When these diagnostic modalities are discordant, not definitive, or when the epileptogenic zone is close to eloquent cortex, invasive EEG, complemented by other imaging techniques may be needed. These include magnetoencephalography, single photon emission tomography, various types of positron emission tomography, various magnetic resonance imaging modalities (functional, diffusion weighted, other) and other emerging and experimental techniques. While MRI, video-EEG, and neuropsychological assessments are well established components of the presurgical evaluation, the use of the new emerging imaging technologies is dictated by the degree of anatomo-electro-clinical correlations, and, awaiting multicentric studies and more detailed guidelines, remains center-dependent.

Motor and cognitive outcomes in children after functional hemispherectomy

PURPOSE

Medically intractable epilepsy is a chronic recurrence of seizures that often requires surgery to reduce or eliminate them. Although a reduction of seizures is the primary goal of hemispherectomy, the effect of surgery on motor and cognitive skills is also of importance. This review will provide a discussion of (1) evidence regarding motor and cognitive outcomes, (2) predictors of these outcomes, and (3) neural mechanisms responsible for preservation of function after hemispherectomy.

SUMMARY OF KEY POINTS

Motor and cognitive outcomes after hemispherectomy are variable and depend on many predictors including etiology and duration of seizure disorder, age at the time of surgery, premorbid status, and postsurgical seizure control. A refined ipsilateral pathway may explain the preservation of motor function in some children.

CONCLUSIONS

A clear understanding of outcome predictors is important for planning effective rehabilitative programs after surgery.

Hemispherectomy sustained before adulthood does not cause persistent hemispatial neglect

INTRODUCTION

Hemispatial neglect has been well established in adults following acute ischemic stroke, but has rarely been investigated in children and young adults following brain injury. It is known that young brains have a tremendous potential for reorganization; however, there is controversy as to whether functions are assumed by the opposite hemisphere, or perilesional areas in the same hemisphere. Patients with intractable epilepsy who undergo hemispherectomy for treatment are missing the entire cortex on one side following surgery. In these patients, only the opposite hemisphere is available to assume function. Therefore, they provide the unique opportunity to determine in what cases the left or right hemisphere can take over the spatial attention functions of the opposite hemisphere following damage. The objective of this study was to determine the incidence and types of hemispatial neglect in children and young adults following both right- and left-sided hemispherectomy; which types of spatial attention functions can be assumed by the opposite hemisphere; and whether factors like their age at time of surgery, handedness, or gender influence recovery.

METHODS

Thirty-two children and young adults who had previously undergone hemispherectomy were administered two tests to evaluate for two types of hemispatial neglect: a gap detection test and a line cancellation test. Egocentric neglect was defined as significantly more omissions of targets on the contralesional versus ipsilesional side of the page (by chi square analysis; p<.05). Allocentric neglect was defined as significantly more errors in detecting contralesional versus ipsilesional gaps in circles.

RESULTS

Only one of the patients displayed statistically significant hemispatial egocentric neglect on the line cancellation test, and none of the patients displayed statistically significant egocentric or allocentric neglect on the gap detection test.

CONCLUSIONS

These results imply that reorganization to the contralateral hemisphere occurs peri-hemispherectomy, as there are no perilesional areas to assume function.

Outcomes of epilepsy surgery in adults and children

Surgery is widely accepted as an effective therapy for selected individuals with medically refractory epilepsy. Numerous studies in the past 20 years have reported seizure freedom for at least 1 year in 53-84% of patients after anteromesial temporal lobe resections for mesial temporal lobe sclerosis, in 66-100% of patients with dual pathology, in 36-76% of patients with localised neocortical epilepsy, and in 43-79% of patients after hemispherectomies. Reported rates for non-resective surgery have been less impressive in terms of seizure freedom; however, the benefit is more apparent when reported in terms of significant seizure reductions. In this Review, we consider the outcomes of surgery in adults and children with epilepsy and review studies of neurological and cognitive sequelae, psychiatric and behavioural outcomes, and overall health-related quality of life.