Surgical treatment of West syndrome

The case against secondary epileptogenesis

Secondary epileptogenesis is a theory that hypothesizes that uncontrolled seizures in people with epilepsy lead to the development of new sites of seizure onset. This process has often been cited when people experience a new seizure type after a period of poor seizure control. The theory proposes that repeated seizures induce changes in regions of the brain that are regularly recruited into the seizure. These hypothetical changes can then lead to a new, independent seizure onset zone. The concept is based on a number of clinical observations which secondary epileptogenesis could explain. However there are alternative explanations from the clinic as well as from the laboratory that call the process into question. In this review some of the observations that have been used to support the theory will be reviewed, and the many counterarguments will be presented. At this time there is little evidence to support secondary epileptogenesis and much to refute it.

Tailoring Materials for Epilepsy Imaging: From Biomarkers to Imaging Probes

Excising epileptic foci (EF) is the most efficient approach for treating drug-resistant epilepsy (DRE). However, owing to the vast heterogeneity of epilepsies, EF in one-third of patients cannot be accurately located, even after exhausting all current diagnostic strategies. Therefore, identifying biomarkers that truly represent the status of epilepsy and fabricating probes with high targeting specificity are prerequisites for identifying the "concealed" EF. However, no systematic summary of this topic has been published. Herein, the potential biomarkers of EF are first summarized and classified into three categories: functional, molecular, and structural aberrances during epileptogenesis, a procedure of nonepileptic brain biasing toward epileptic tissue. The materials used to fabricate these imaging probes and their performance in defining the EF in preclinical and clinical studies are highlighted. Finally, perspectives for developing the next generation of probes and their challenges in clinical translation are discussed. In general, this review can be helpful in guiding the development of imaging probes defining EF with improved accuracy and holds promise for increasing the number of DRE patients who are eligible for surgical intervention.

Discrimination of secondary hypsarrhythmias to Zika virus congenital syndrome and west syndrome based on joint moments and entropy measurements

Hypsarrhythmia is a specific chaotic morphology, present in the interictal period of the electroencephalogram (EEG) signal in patients with West Syndrome (WS), a severe form of childhood epilepsy and that, recently, was also identified in the examinations of patients with Zika Virus Congenital Syndrome (ZVCS). This innovative work proposes the development of a computational methodology for analysis and differentiation, based on the time-frequency domain, between the chaotic pattern of WS and ZVCS hypsarrhythmia. The EEG signal time-frequency analysis is carried out from the Continuous Wavelet Transform (CWT). Four joint moments—joint mean—\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mu _{(t,f)}$$\end{document}μ(t,f), joint variance—\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sigma _{(t,f)}^2$$\end{document}σ(t,f)2, joint skewness—\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\lambda _{(t,f)}$$\end{document}λ(t,f), and joint kurtosis—\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\kappa _{(t,f)}$$\end{document}κ(t,f)—and four entropy measurements—Shannon, Log Energy, Norm, and Sure—are obtained from the CWT to compose the representative feature vector of the EEG hypsarrhythmic signals under analysis. The performance of eight classical types of machine learning algorithms are verified in classification using the k-fold cross validation and leave-one-patient-out cross validation methods. Discrimination results provided 78.08% accuracy, 85.55% sensitivity, 73.21% specificity, and AUC = 0.89 for the ANN classifier.

Corpus Callosotomy in the Modern Era: Origins, Efficacy, Technical Variations, Complications, and Indications

Corpus callosotomy is among the oldest surgeries performed for drug-resistant epilepsy (DRE). First performed in 1940, various studies have since assessed its outcomes in various patient populations in addition to describing different extents of sectioning and emerging technologies (i.e. endoscopic, laser interstitial thermal therapy, and radiosurgery). In order to capture the current state and offer a reappraisal, we comprehensively review corpus callosotomy's origins, efficacy for various seizure types, technical variations, complications, and indications and compare the procedure to vagus nerve stimulation therapy which has similar indications. We consider corpus callosotomy to be a safe and efficacious procedure that should be considered by clinicians when appropriate. Furthermore, it can also play an important role in treating patients with DRE in low-to-middle-income countries where resources are limited.

Reciprocal control of translation and transcription in autism spectrum disorder

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social communication and the presence of restricted patterns of interest and repetitive behaviors. ASD is genetically heterogeneous and is believed to be caused by both inheritable and de novo gene variations. Studies have revealed an extremely complex genetic landscape of ASD, favoring the idea that mutations in different clusters of genes interfere with interconnected downstream signaling pathways and circuitry, resulting in aberrant behavior. In this review, we describe a select group of candidate genes that represent both syndromic and non-syndromic forms of ASD and encode proteins that are important in transcriptional and translational regulation. We focus on the interplay between dysregulated translation and transcription in ASD with the hypothesis that dysregulation of each synthetic process triggers a feedback loop to act on the other, which ultimately exacerbates ASD pathophysiology. Finally, we summarize findings from interdisciplinary studies that pave the way for the investigation of the cooperative impact of different genes and pathways underlying the development of ASD.

Objective interictal electrophysiology biomarkers optimize prediction of epilepsy surgery outcome

Researchers have looked for rapidly- and objectively-measurable electrophysiology biomarkers that accurately localize the epileptogenic zone. Promising candidates include interictal high-frequency oscillation and phase-amplitude coupling. Investigators have independently created the toolboxes that compute the high-frequency oscillation rate and the severity of phase-amplitude coupling. This study of 135 patients determined what toolboxes and analytic approaches would optimally classify patients achieving post-operative seizure control. Four different detector toolboxes computed the rate of high-frequency oscillation at ≥80 Hz at intracranial EEG channels. Another toolbox calculated the modulation index reflecting the strength of phase-amplitude coupling between high-frequency oscillation and slow-wave at 3–4 Hz. We defined the completeness of resection of interictally-abnormal regions as the subtraction of high-frequency oscillation rate (or modulation index) averaged across all preserved sites from that averaged across all resected sites. We computed the outcome classification accuracy of the logistic regression-based standard model considering clinical, ictal intracranial EEG and neuroimaging variables alone. We then determined how well the incorporation of high-frequency oscillation/modulation index would improve the standard model mentioned above. To assess the anatomical variability across non-epileptic sites, we generated the normative atlas of detector-specific high-frequency oscillation and modulation index. Each atlas allowed us to compute the statistical deviation of high-frequency oscillation/modulation index from the non-epileptic mean. We determined whether the model accuracy would be improved by incorporating absolute or normalized high-frequency oscillation/modulation index as a biomarker assessing interictally-abnormal regions. We finally determined whether the model accuracy would be improved by selectively incorporating high-frequency oscillation verified to have high-frequency oscillatory components unattributable to a high-pass filtering effect. Ninety-five patients achieved successful seizure control, defined as International League against Epilepsy class 1 outcome. Multivariate logistic regression analysis demonstrated that complete resection of interictally-abnormal regions additively increased the chance of success. The model accuracy was further improved by incorporating z-score normalized high-frequency oscillation/modulation index or selective incorporation of verified high-frequency oscillation. The standard model had a classification accuracy of 0.75. Incorporation of normalized high-frequency oscillation/modulation index or verified high-frequency oscillation improved the classification accuracy up to 0.82. These outcome prediction models survived the cross-validation process and demonstrated an agreement between the model-based likelihood of success and the observed success on an individual basis. Interictal high-frequency oscillation and modulation index had a comparably additive utility in epilepsy presurgical evaluation. Our empirical data support the theoretical notion that the prediction of post-operative seizure outcomes can be optimized with the consideration of both interictal and ictal abnormalities.

Three different scenarios for epileptic spasms

Epileptic Spasms (ES) is a type of seizure usually occurring in the context of a severe childhood epileptic syndrome associated to significant Electroencephalogram (EEG) abnormalities. There are three scenarios in which ES may occur. The first one is represented by West Syndrome (WS): ES occur in a previously non encephalopathic infant in association with the development of a hypsarrhythmic EEG pattern. In most cases, standard treatment with Adrenocorticotropic Hormone (ACTH), steroids or vigabatrin leads to a reversal of the electroclinical picture. The second scenario is represented by Developmental and Epileptic Encephalopathies (DEEs): ES are documented, often along other seizures types, in an infant who often shows developmental delay since birth; the EEG pattern is pathological both in wakefulness and in sleep, without typical features of hypsarrhythmia; therapies (with the exception of few potentially treatable syndromes) are poorly effective. The last scenario is represented by ES in the context of Focal Epilepsies (FEs): ES, sometimes showing focal signs or closely related to focal seizures, are associated with focal brain lesions. Treatment with ACTH, steroids or vigabatrin may not be effective as well as antiepileptic drugs for focal epilepsies. In drug-resistant patients, surgery should be considered. Although there are some gaps in our current scientific knowledge concerning the peculiar electroclinical and physiopathological features of ES, we nowadays possess the necessary tools to correctly frame this unique seizure type into one of these scenarios and therefore properly manage the diagnostic and therapeutic workup.

Infantile Spasms and West Syndrome - A Clinician's Perspective

Infantile spasms, though long recognised, are still a cause of significant morbidity in children. The knowledge of their etiology and pathogenesis is still evolving. Even the management strategies vary among different centres. Hormonal treatments and vigabatrin have been recognised as effective but controversies prevail on the exact protocols that best balance the risk benefit ratio. Collaborative studies have begun to provide some clarity on some of the management issues but further large scale studies that further standardise protocols are a felt need. This article attempts to provide a clinically relevant summary of the current knowledge.

Evolution of Surgical Management for Intractable Epileptic Spasms

The understanding and management of epileptic spasms has considerably evolved since the mid 19th century. The realization that epileptic spasms can be generated from a focal brain lesion played a pivotal role in the development of neurosurgical management for intractable forms of this epilepsy. During pre-surgical planning, the addition of functional FDG PET imaging has further refined the electroencephalographic localization of epileptogenic lesions. In some cases, neurosurgical resection of a focus that is co-localized by the FDG PET scan and electroencephalography can lead to partial or complete reversal of developmental delay along with reduced seizure frequency or seizure freedom. In cases where near-complete hemispheric cortex is implicated in spasm generation, subtotal hemispherectomy has shown encouraging results. Moreover, palliative resection of the major perpetrating focus in carefully chosen patients with bilateral multifocal spasms has also led to favorable outcomes. However, in patients with tuberous sclerosis with high tuber burden, the localizing value of FDG PET imaging may be limited. In such cases, employment of AMT PET technology has become a valuable tool for localization of actively epileptogenic tubers. This article highlights the historic steps in the successful advancements of neurosurgical interventions for the treatment of intractable epileptic spasms.

Cortical high-frequency oscillation loops initiate spasm seizures

Some epileptic spasms are classified into focal-onset seizures. However, the cortical network underlying this kind of spasm seizure is not yet clear. Four patients with epileptic spasms who underwent intracranial electrode implantation and focal resection surgery were studied. All the patients had good outcomes, and three of them with intellectual disability showed improved intelligence after surgery. The power spectra characteristics of electrocorticography and the dynamic functional network changes of epileptic spasms were investigated. Electrocorticography power in the resected zone peaked 0.5 seconds before the clinical seizure onset and was especially prominent in the γ and ripple bands. The functional network analysis showed particular dynamic patterns of high-frequency activity among the resected zone, sensorimotor cortex, and the other region. In the gamma band, during the interictal segment, the information flow from the resected zone and the other region to the sensorimotor cortex was prominent. During the preictal segment, the information flow from the resected zone and sensorimotor cortex to the other region became stronger. In the ripple band, during the interictal segment, the information flow from the resected zone to the sensorimotor cortex and the other region was high. During the preictal segment, the information flow between the resected zone and sensorimotor cortex became stronger. Our results suggest that the sensorimotor cortex is a requisite for spasm seizure initiation, and the ripple activity loop between the resected zone and sensorimotor cortex may give rise to the seizure onset with the help of the gamma activity loop between the sensorimotor cortex and the other region for activation spreading.

Magnetoencephalographic Recordings in Infants: A Retrospective Analysis of Seizure-Focus Yield and Postsurgical Outcomes

PURPOSE

Magnetoencephalography (MEG) is often incorporated into the presurgical work-up of children with pharmacoresistant epilepsy. There is growing literature on its role in improving selection for epilepsy surgery, particularly when brain MRI is "non-lesional" or in patients with recurrence or intractable seizures after epilepsy surgery. There are, however, no reports on the extrapolation of its role in the presurgical decision-making process of infants.

METHODS

We performed a retrospective analysis of infants who underwent MEG over a 10-year period at our center for presurgical work-up. We reviewed medical records to ascertain seizure history, work-up procedures including brain MRI and scalp EEG, and in the case of surgery, intracranial recordings, operative notes, and follow-up outcomes.

RESULTS

We identified 31 infants (<2 years of age) who underwent MEG recordings. Despite EEG interictal readings showing patterns of generalized dysfunction in 80%, MEG was able to pinpoint the foci of epileptic activity in 45%. In the MRI-negative group, 44% had focal lateralized interictal spikes on MEG. The sensitivity of MEG to detect interictal epileptiform activity was 90%, and its ability to provide additional information was 28%. Among 18 infants who had surgery, 13 became seizure free at follow-up. The percentage of infants with a focal spike volume on MEG studies and a seizure-free outcome was 66%.

CONCLUSIONS

MEG recordings in infants were found to be as sensitive for identifying seizure focus as other age groups, also supplying additional information to the decision-making process and validating its role in the presurgical work-up of infants with intractable epilepsy.

Multimodal localization and surgery for epileptic spasms of focal origin: a review

Epileptic spasms (ES) are a common manifestation of intractable epilepsy in early life and can lead to devastating neurodevelopmental consequences. Epilepsy surgery for ES is challenging because of inherent difficulties in localizing the epileptogenic zone in affected infants and children. However, recent clinical series of resective neurosurgery for ES suggest that not only is surgery a viable option for appropriately selected patients, but postoperative seizure outcomes can be similar to those achieved in other types of focal epilepsy. Increased awareness of ES as a potentially focal epilepsy, along with advances in neuroimaging and invasive monitoring technologies, have led to the ability to surgically treat many patients with ES who were previously not considered surgical candidates. In this study, the authors review the current state of epilepsy surgery for ES. Specifically, they address how advances in neuroimaging and invasive monitoring have facilitated patient selection, presurgical evaluation, and ultimately, resection planning.

Phase-amplitude coupling between interictal high-frequency activity and slow waves in epilepsy surgery

OBJECTIVE

We hypothesized that the modulation index (MI), a summary measure of the strength of phase-amplitude coupling between high-frequency activity (>150 Hz) and the phase of slow waves (3-4 Hz), would serve as a useful interictal biomarker for epilepsy presurgical evaluation.

METHODS

We investigated 123 patients who underwent focal cortical resection following extraoperative electrocorticography recording and had at least 1 year of postoperative follow-up. We examined whether consideration of MI would improve the prediction of postoperative seizure outcome. MI was measured at each intracranial electrode site during interictal slow-wave sleep. We compared the accuracy of prediction of patients achieving International League Against Epilepsy class 1 outcome between the full multivariate logistic regression model incorporating MI in addition to conventional clinical, seizure onset zone (SOZ), and neuroimaging variables, and the reduced logistic regression model incorporating all variables other than MI.

RESULTS

Ninety patients had class 1 outcome at the time of most recent follow-up (mean follow-up = 5.7 years). The full model had a noteworthy outcome predictive ability, as reflected by regression model fit R² of 0.409 and area under the curve (AUC) of receiver operating characteristic plot of 0.838. Incomplete resection of SOZ (P < 0.001), larger number of antiepileptic drugs at the time of surgery (P = 0.007), and larger MI in nonresected tissues relative to that in resected tissue (P = 0.020) were independently associated with a reduced probability of class 1 outcome. The reduced model had a lower predictive ability as reflected by R² of 0.266 and AUC of 0.767. Anatomical variability in MI existed among nonepileptic electrode sites, defined as those unaffected by magnetic resonance imaging lesion, SOZ, or interictal spike discharges. With MI adjusted for anatomical variability, the full model yielded the outcome predictive ability of R² of 0.422, AUC of 0.844, and sensitivity/specificity of 0.86/0.76.

SIGNIFICANCE

MI during interictal recording may provide useful information for the prediction of postoperative seizure outcome.

Upregulations of CRH and CRHR1 in the Epileptogenic Tissues of Patients with Intractable Infantile Spasms

AIM

Infantile spasms (IS) are an age-specific epileptic syndrome with specific clinical symptom and electroencephalogram (EEG) features, lacking treatment options, and a poor prognosis. Excessive endogenous corticotropin-releasing hormone (CRH) in infant brain might result in IS. However, the data from human IS are limited. In our study, we investigated the expressions of CRH and its receptor type 1 (CRHR1) in surgical tissues from patients with IS and autopsy controls.

METHODS

Specimens surgically removed from 17 patients with IS, and six autopsy controls were included in the study. Real-time PCR, Western blotting, and immunostaining were used to detect the expressions of mRNA, protein expression, and distribution. The correlation between variates was analyzed by Spearman rank correlation.

RESULTS

The expressions of CRH and CRHR1 were significantly upregulated in the epileptogenic tissues of IS patients compared with the control group. CRH was distributed mainly in neurons, while CRHR1 was distributed in neurons, astrocytes, and microglia. The expression levels of CRH and CRHR1 were positively correlated with the frequency of epileptic spasms. Moreover, the expression of protein kinase C (PKC), which was an important downstream factor of CRHR1, was significantly upregulated in the epileptogenic tissues of patients with IS and was positively correlated with the CRHR1 expression levels and the frequency of epileptic spasms.

CONCLUSION

These results suggest that the CRH signal transduction pathway might participate in the epileptogenesis of IS, supporting the hypothesis that CRH is related to the pathogenesis of IS.

Surgical versus medical treatment for children with epileptic encephalopathy in infancy and early childhood: Results of an international multicenter cohort study in Far-East Asia (the FACE study)

OBJECTIVE

To compare the seizure and developmental outcomes in infants and young children with epileptic encephalopathy who have undergone surgical and medical treatments.

METHODS

An international, multicenter, observational cohort study was undertaken. A total of 317 children aged <6 years, who had frequent disabling seizures despite intensive medical treatments, were registered. Among the enrolled children, 250 were treated medically (medical group), 31 underwent resective surgery (resective group), and 36 underwent palliative surgery [callosotomy (n=30) or vagal nerve stimulation (n=6); palliative group] on admission. Seizure and developmental outcomes were obtained for 230 children during the 3-year follow-up period. Cox proportional hazard model was used to adjust for clinical backgrounds among treatment groups when comparing the seizure-free survival rates.

RESULTS

At the 3-year follow-up, seizure-free survival was 15.7%, 32.1%, and 52.4% in the medical, palliative, and resective groups, respectively. The adjusted hazard ratios for seizure recurrence in the resective and palliative groups versus the medical group were 0.43 (95% CI, 0.21-0.87, P=0.019) and 0.82 (95% CI, 0.46-1.46, P=0.50), respectively; the former was statistically significant. Regarding the developmental outcome, the mean DQs in the resective group increased significantly compared to those in the medical group during the follow-up (P<0.01). As for subgroup analysis, better seizure and development outcomes were demonstrated in the resective group compared to the medical group in children with nonsyndromic epilepsies (those to which no known epilepsy syndromes were applicable).

SIGNIFICANCE

These results suggest that surgical treatments, particularly resective surgeries, are associated with better seizure and developmental outcomes compared with successive medical treatment. The present observations may facilitate the identification of infants and young children with epileptic encephalopathy who could benefit from surgery.

Outcomes of epilepsy surgery in childhood-onset epileptic encephalopathy

PURPOSE

to evaluate the outcomes and role of epilepsy surgery in children with intractable epileptic encephalopathy (EE).

METHODS

ninety-five children (64 boys, 31 girls) with intractable EE were treated by epilepsy surgery at Severance Children's Hospital from 2003 to 2008. Surgical treatments included lobar resection, hemispherotomy and corpus callosotomy (CC). Seventy-six children were Lennox-Gastaut syndrome (LGS), and 19 had West syndrome.

RESULTS

of the 76 patients with LGS, CC was performed in 37 patients (48.7%), lobar resection in 29 (38.2%) and hemispherotomy in 10 (13.2%). Of the 19 patients with West syndrome, respective surgery was performed in 15 patients (78.9%) and CC in 4 (21.1%). Of the patients receiving respective surgery, Engel's class I outcomes were achieved for 24 of 39 (61.5%) of LGS patients, and for 9 of 15 (60.0%) of West syndrome. Malformations of cortical development were commonly observed, appearing in 73.5% (36/49). In neuropsychiatric tests, 19 of 27 with LGS demonstrated improvement in postoperative cognitive function. More significant intellectual improvement correlated well with shorter epilepsy duration, good seizure outcomes, and decreased number of antiepileptic drugs.

CONCLUSIONS

epilepsy surgery should be considered in treating childhood intractable EE with expectation of improvement of both seizure and cognitive outcomes, even in cases of LGS.

Atividade eletromiográfica dos extensores de tronco durante manuseio pelo Método Neuroevolutivo Bobath

INTRODUÇÃO: Paralisia cerebral é um distúrbio caracterizado por alterações no desenvolvimento da atividade, do movimento e da postura. O Conceito Neuroevolutivo Bobath é um método utilizado na reabilitação neuropediátrica, fundamentando-se na facilitação da aquisição de habilidades sensório-motoras de acordo com a sequência de desenvolvimento neuropsicomotor normal. OBJETIVO: Verificar atividade eletromiográfica de músculos envolvidos no controle cervical nos planos frontal, sagital e transverso, mediante manuseio em pontos-chave de controle, objetivando transferência de peso e estabilização corporal. MATERIAIS E MÉTODOS: Trata-se de uma avaliação quantitativa em um estudo de caso, no qual uma paciente de sete anos de idade, com diagnóstico clínico de paralisia cerebral e síndrome de West, foi submetida à análise eletromiográfica da musculatura envolvida no controle cervical, mediante manuseio em pontos-chave de controle. O registo ocorreu durante o manuseio utilizando postura de decúbito ventral sobre cunha e postura de decúbito lateral sobre o solo. RESULTADOS: O sinal eletromiográfico dos extensores e flexores na região cervical intensificou-se mediante manuseio para transferência de peso em ponto-chave de quadril em ambas as posturas. Embora o sinal de base tenha sido ampliado durante a transferência de peso para o quadril, o registro eletromiográfico nos segmentos musculares avaliados foi superior no decúbito lateral. CONCLUSÕES: Verificou-se que a transferência de peso para o quadril induziu facilitação do controle cervical e que o decúbito lateral de forma repetida e sustentada, mediante correto manuseio, alinhamento e transferência de peso, facilitou de forma mais pronunciada a atividade muscular na região cervical e de tronco superior do que o manuseio em decúbito ventral sobre a cunha.

The usefulness of subtraction ictal SPECT and ictal near-infrared spectroscopic topography in patients with West syndrome

The recent findings on subtraction ictal SPECT and ictal near-infrared spectroscopic topography in patients with West syndrome were summarized and its availability for presurgical evaluation was discussed. The subtraction ictal SPECT study in patients with West syndrome demonstrated the cortical epileptic region and subcortical involvement, which may consist of epilepsy networks related to the spasms. Moreover, subtraction ictal SPECT may have predictive power for short-term seizure outcome. Patients with a symmetric hyperperfusion pattern are predicted to have a better seizure outcome, whereas patients with asymmetric hyperperfusion pattern may develop poor seizure control. Importantly, asymmetric MRI findings had no predictive power for seizure outcome. Multichannel near-infrared spectroscopic topography applied to the patients with West syndrome detected an increase in regional cerebral blood volume in multiple areas which were activated either simultaneously or sequentially during spasms. Topographic changes in cerebral blood volume were closely correlated with spasm phenotype, suggesting that the cortex is involved in the generation of spasms. In conclusion, subtraction ictal SPECT may be considered as a useful tool for presurgical evaluation of patients with West syndrome and investigation of the pathophysiology of spasms. The ictal near-infrared spectroscopic topography should be more investigated to see if this is useful tool for presurgical evaluation.

Surgical treatment of pediatric epileptic encephalopathies

Pediatric epileptiform encephalopathies are a group of neurologically devastating disorders related to uncontrolled ictal and interictal epileptic activity, with a poor prognosis. Despite the number of pharmacological options for treatment of epilepsy, many of these patients are drug resistant. For these patients with uncontrolled epilepsy, motor and/or neuropsychological deterioration is common. To prevent these secondary consequences, surgery is often considered as either a curative or a palliative option. Magnetic resonance imaging to look for epileptic lesions that may be surgically treated is an essential part of the workup for these patients. Many surgical procedures for the treatment of epileptiform encephalopathies have been reported in the literature. In this paper the evidence for these procedures for the treatment of pediatric epileptiform encephalopathies is reviewed.

Clinical analysis of catastrophic epilepsy in infancy and early childhood: results of the Far-East Asia Catastrophic Epilepsy (FACE) study group

PURPOSE

We studied children younger than 6years old who developed catastrophic epilepsy and were registered in the FACE study group to clarify their clinical characteristics and prevalence of seizure as well as epilepsy types.

SUBJECTS

Subjects were prospectively recruited from children with epilepsy who satisfied the following criteria and underwent intensive examination between 2009 and 2012 in 14 collaborative centers: (1) younger than 6years old and (2) more than 10 seizures/month refractory to all available medical treatments including ACTH therapy, leading to significant psychosocial morbidity.

METHODS

We analyzed epilepsy onset age, predominant seizure type, etiology, neuropsychological findings, and syndromic classification according to the pre-determined registration format.

RESULTS

A total of 314 children were enrolled in this study. Epilepsy onset age in 239 cases (80%) was younger than 12months. The most frequent seizure type was epileptic spasms (ES), followed by generalized tonic seizures (GTS), which accounted for 42% and 20%, respectively. West syndrome (WS) was the most frequent epileptic syndrome and accounted for 37%, followed by unclassified epilepsy at 21%, neocortical epilepsy at 19%, Lennox-Gastaut syndrome at 12%, Dravet syndrome at 4%, Rasmussen syndrome at 2%, and others. The two most frequent causes of epilepsy were cortical dysplasia and chromosomal anomalies, as shown in 16% and 6%, respectively. However, the etiology of nearly one half of all patients remained unknown. Psychomotor development was already worse than a moderate degree in 62% of subjects at the first examination.

CONCLUSION

The highest proportion of catastrophic epilepsy was WS and its related syndromes featuring ES and GTS, followed by neocortical epilepsy, whose psychomotor development was significantly retarded at examinations.

A long-term, clinical study on symptomatic infantile spasms with focal features

BACKGROUND

We studied the clinical, neuroradiological and EEG characteristics of patients with infantile spasms (IS) who showed focal features to reveal their long-term prognoses and treatment responses.

SUBJECTS AND METHODS

Subjects included 69 patients with IS who consecutively visited our hospital. We tentatively classified the subjects into focal IS (fIS) and diffuse WS (dIS) groups based on the presence and absence of more than two of the following findings, respectively: (1) epileptic spasms (ES) that were asymmetric, (2) a focal epileptic EEG abnormality, (3) a lateralized neurological abnormality, (4) a focal brain MRI and (5) a focal SPECT abnormality.

RESULTS

We found 23 cases with fIS and 46 cases with dIS. ES responded more frequently in fIS than dIS group (100% vs. 80%; P=0.02) to the initial ACTH trial although the subsequent seizure relapse occurred more frequently in fIS than dIS group (74% vs. 38%; P=0.0006). The second course of ACTH trial brought a short as well as long-term remission in both groups (6/8 cases vs. 5/6 cases). Later in the clinical course, the fIS patients tended to display a focal epileptic EEG abnormality and to develop focal seizures. In our series, approximately one-third of patients with fIS later showed either only a focal epileptic EEG abnormality, a focal epileptic EEG abnormality with focal seizures, or bilateral asymmetric EEG foci with disabling seizures, respectively.

CONCLUSION

It is useful to classify patients with IS into fIS and dIS groups based on various lateralizing signs because the classification provides practical information regarding the long-term outcome and treatment strategy.

Long-term developmental outcome in patients with West syndrome after epilepsy surgery

It has been hypothesized that early seizure control may prevent children with intractable epileptic spasms (ES) from developmental regression and may contribute to better developmental outcome. The effectiveness of surgery for ES has been reported. We investigated long-term post-operative outcomes of seizure control and development in patients with symptomatic West syndrome (S-WS) who underwent epilepsy surgery. Six children who underwent surgical intervention for intractable ES were retrospectively investigated. Cortical malformations were observed on pre-operative MRI in all patients, with hemispheric or multilobar involvement in four children and focal lesions in two. Following surgery, we measured motor function, developmental age (DA), language skills, and sociopsychological function for up to 7years (mean, 4.9years). Post-operative seizure outcome was Engel Class I (n=4) or III (n=2). Motor function and DA was increased following surgery in six and five patients, respectively. Two patients started to speak in sentences following focal resection. Autistic features were noted in four of the five examined patients post-operatively. None of the patients showed developmental regression following surgery. Epilepsy surgery for S-WS with ES may result in good seizure control and improvement in motor development. Improvement in cognitive function was modest in this small cohort of children and autistic features were noted post-operatively in a substantial proportion of the children. While seizure control can be obtained by epilepsy surgery, early intervention for sociopsychological comorbidities may be warranted in children with S-WS.

Different cortical involvement pattern of generalized and localized spasms: a magnetoencephalography study

We report successful magnetoencephalography (MEG) recording in a child who had generalized epileptic spasms (ESs) as well as ESs involving the legs only during the recording. MEG source localization results demonstrated that (1) the interictal epileptiform discharges and both types of ESs had the same origin, that is, the right parietal region, and (2) the two types of ESs had different cortical spread patterns, that is, epileptic involvement localized to the right parietal region in spasms of the legs and rapid diffuse involvement in generalized spasms. In this case, MEG provided new insight into the mechanisms underlying the two types of ESs: both types were generated from the same focus, and in generalized ESs, abnormal excitation spread to cortical areas diffusely.

Uncovered primary seizure foci in Lennox-Gastaut syndrome after corpus callosotomy

PURPOSE

Corpus callosotomy (CC) is a palliative surgical procedure to control atonic, tonic, or generalized tonic-clonic seizure in Lennox-Gastaut syndrome (LGS). Here, we report patients with LGS who underwent resective surgery, following CC better delineating the presumed seizure foci localized in one hemisphere.

METHODS

We retrospectively reviewed seven patients with LGS who underwent CC and subsequent cortical resection. The median follow-up duration after lobectomy was 20 months (range, 15-54 months) and three patients had follow-up periods over 24 months. The findings of video electroencephalography (EEG) monitoring, structural and functional neuroimagings were compared between pre- and post-CC.

RESULTS

Four patients had Engel class I and one patient had Engel class II outcomes following cortical resection; post-CC, compared to pre-CC, showed better localized ictal/interictal epileptiform discharges in the unilateral frontal area in two patients, in the unilateral parieto-temporo-occipital areas in one patient and in the unilateral fronto-temporal areas in the remaining two patients. Two patients had Engel Class III outcome following cortical resection; post-CC EEG continued to show multifocal epileptiform discharges but predominantly arising from a unilateral frontal area. Following CC, positron emission tomography showed localized glucose hypometabolism of which location was concordant with post-CC EEG abnormalities in all patient. Similarly, ictal/interictal single photon emission computed tomography also showed localized abnormalities concordant with post-CC EEG abnormalities in five of the six patients. Pathological assessment revealed cortical dysplasia in six patients, whereas no pathological abnormality was found in the remaining patient, who obtained Engel Class I outcome following cortical resection.

CONCLUSION

CC could change EEG findings, glucose metabolisms and cerebral blood flows, and it is sometimes helpful in delineating the primary seizure focus in patients with LGS.

Epilepsy surgery of posterior quadrant dysplasia in the first year of life: experience of a single centre with long term follow-up

Posterior quadrant dysplasia (PQD) is a rare variant of cortical dysplasia involving the posterior regions of a single hemisphere. It is always associated with early onset, refractory epilepsy often characterized by a "catastrophic" evolution. The experience on its surgical management during the first year of life is limited to sporadic, isolated cases. Between 2002 and 2005, four children less than one-year-old and affected by drug-resistant epilepsy associated with PQD were admitted to our Institution and underwent surgical treatment. One patient remained seizure-free during all the follow-up (Engel I). The remaining three children showed a recurrence of the seizures, requiring subsequent surgical procedures in two cases. In one case (Engel II), the seizure control has been obtained thanks to pharmacological treatment. The other two patients respectively had only a partial (Engel III) and a less relevant reduction of the number of seizures (Engel IV). Both the epileptic and the neuropsychological outcome of our series were significantly influenced by persistent contralateral interictal anomalies rather than by the timing of the surgical procedure. Unpredictable results should be expected in this kind of patients if there is the detection of contralateral independent epileptiform activities on the EEG at diagnosis. Parents and relatives should be aware of the results' variability, even though a reduction of seizures may be expected, enabling an easier handling of the child's condition.

Infantile spasms: review of the literature and personal experience

This epileptic disorder has become a classic topic for neuropediatricians and the interest is documented by the large number of publications on this subject.The relative frequency among the epileptic syndromes is an another reason why not only neuropediatricians but also general pediatricians must be fully informed about diagnostic, clinical, imaging and genetic aspects.Early diagnosis is of paramount importance in order to obtain even complete results in patients with so called idiopathic situations. A number of problems are still to be solved. There is no agreement on the type and the schedule of treatment. A common denominator about this problem is not jet available even if some advances in this regard have been accomplished. Of paramount importance is an accurate clinical and laboratory examination as a prerequisite regarding prognosis and results of therapy in every single case.However, even if more than 170 years have elapsed since the first communication of dr. West on the peculiar syndrome that his child was suffering of, the interest of scientists on this subject has now been enriched and rewarded.

Applications of positron emission tomography in the newborn nursery

Positron emission tomography (PET) is a relatively noninvasive imaging test that is able to detect abnormalities in different organs based on derangements in the chemical functions and/or receptor expression at the cellular level. PET imaging of the brain has been shown to be a powerful diagnostic tool for detecting neurochemical abnormalities associated with various neurologic disorders as well as to study normal brain development. Although its use in detecting neurological abnormalities has been well described in adults and pediatrics, its application in the newborn nursery has not been explored adequately. Early detection of brain injury secondary to intrauterine and perinatal insults using PET imaging can provide new insight in prognosis and in instituting early therapy. In this review, the authors describe applications of PET imaging in the newborn nursery specifically related to the detection of metabolic changes seen in hypoxic ischemic encephalopathy, neonatal seizures, and neuroinflammation in the neonatal period.

PET in the Assessment of Pediatric Brain Development and Developmental Disorders

This article discusses and reviews the role and contribution of PET in understanding the structural and functional changes that occur during brain development, and how these changes relate to behavioral and cognitive development in the infant and child. Data regarding various aspects of brain development, such as glucose metabolism, protein synthesis, and maturation and development of neurotransmitter systems will help in understanding the pathogenesis and neurologic basis of various developmental and neurologic disorders. This may help in following disease evolution and progression, planning and development of various therapeutic interventions, timing these interventions and monitoring their responses, and rendering long-term prognostication.

Role of subdural electrocorticography in prediction of long-term seizure outcome in epilepsy surgery

Since prediction of long-term seizure outcome using preoperative diagnostic modalities remains suboptimal in epilepsy surgery, we evaluated whether interictal spike frequency measures obtained from extraoperative subdural electrocorticography (ECoG) recording could predict long-term seizure outcome. This study included 61 young patients (age 0.4-23.0 years), who underwent extraoperative ECoG recording prior to cortical resection for alleviation of uncontrolled focal seizures. Patient age, frequency of preoperative seizures, neuroimaging findings, ictal and interictal ECoG measures were preoperatively obtained. The seizure outcome was prospectively measured [follow-up period: 2.5-6.4 years (mean 4.6 years)]. Univariate and multivariate logistic regression analyses determined how well preoperative demographic and diagnostic measures predicted long-term seizure outcome. Following the initial cortical resection, Engel Class I, II, III and IV outcomes were noted in 35, 6, 12 and 7 patients, respectively. One child died due to disseminated intravascular coagulation associated with pseudomonas sepsis 2 days after surgery. Univariate regression analyses revealed that incomplete removal of seizure onset zone, higher interictal spike-frequency in the preserved cortex and incomplete removal of cortical abnormalities on neuroimaging were associated with a greater risk of failing to obtain Class I outcome. Multivariate logistic regression analysis revealed that incomplete removal of seizure onset zone was the only independent predictor of failure to obtain Class I outcome. The goodness of regression model fit and the predictive ability of regression model were greatest in the full regression model incorporating both ictal and interictal measures [R(2) 0.44; Area under the receiver operating characteristic (ROC) curve: 0.81], slightly smaller in the reduced model incorporating ictal but not interictal measures (R(2) 0.40; Area under the ROC curve: 0.79) and slightly smaller again in the reduced model incorporating interictal but not ictal measures (R(2) 0.27; Area under the ROC curve: 0.77). Seizure onset zone and interictal spike frequency measures on subdural ECoG recording may both be useful in predicting the long-term seizure outcome of epilepsy surgery. Yet, the additive clinical impact of interictal spike frequency measures to predict long-term surgical outcome may be modest in the presence of ictal ECoG and neuroimaging data.

Approach to pediatric epilepsy surgery: State of the art, Part II: Approach to specific epilepsy syndromes and etiologies

The second of this 2-part review depicts the specific approach to the common causes of pediatric refractory epilepsy amenable to surgery. These include tumors, malformations due to abnormal cortical development, vascular abnormalities and certain epileptic syndromes. Seizure freedom rates are high (usually 60-80%) following tailored focal resection, lesionectomy, and hemispherectomy. However, in patients in whom the epileptogenic zone overlaps with unresectable eloquent cortex, and in certain epileptic syndromes, seizure freedom may not be achievable. In such cases, palliative procedures such as callosotomy, multiple subpial transections and vagus nerve stimulation can achieve reduction in seizure severity but rarely seizure freedom. Integration of the new imaging techniques and the concepts of neuronal plasticity, the epileptogenic lesion, the ictal onset, symptomatogenic, irritative, and epileptogenic zones is an expanding and dynamic process that will allow us, in the future, to better decide on the surgical approach of choice and its timing.

Long-term outcome of symptomatic infantile spasms established by video-electroencephalography (EEG) monitoring

In this study, we examine the long-term clinical outcome of children with symptomatic infantile spasm. The children between 2 and 18 years of age diagnosed with symptomatic infantile spasms were reviewed. Sixty-eight children (age range, 2-13 years; mean, 4.5 years) met the inclusion criteria. Children who underwent epilepsy surgery were excluded. Age of onset for infantile spasms ranged from 1 to 24 months (mean, 7.1 months). Developmental delay was noted in all; there was seizure freedom in 14 children (20.5%). Infantile spasms were reported as the only seizure type in 10 (14.5%) children older than age 2 years. During the follow-up; symptomatic generalized epilepsy was diagnosed in 23 children (34%) and focal epilepsy in 21 (31%). The long-term outcome of these children remains unchanged in the majority of the children with symptomatic infantile spasms. We could not establish any risk factor that might be related to favorable or adverse outcome.

Focal epileptic spasms, involving one leg, manifesting during the clinical course of west syndrome (WS)

OBJECTIVES

Epileptic spasms (ES) in West syndrome (WS) are classified as being of the generalized seizure type. However, evidence of a focal neocortical origin has been proposed based mainly on surgical WS series. We report herein two infants with WS, whose ES subsequently evolved into focal ES of the right lower extremity.

METHODS

Medical records, electroencephalographic and neuroimaging findings were retrospectively analyzed.

RESULTS

A 2 year-old Japanese girl developed ES at 3 months of age. Focal ES of the right leg manifested one month after successful ACTH therapy performed at 6 months of age. Brief jerking of the right leg, every few seconds, occurred immediately after awakening. A 7 month-old girl with symptomatic WS had developed focal seizures with postural signs at 2 months of age. The seizures gradually diminished and had been replaced by ES by 3 months of age. ES gradually evolved into focal ES of the right leg. A video-polygraphic study demonstrated the ES with marked predominance in the right leg corresponding to a left sided predominant paroxysmal biphasic slow wave complex. Brain MRI revealed no abnormal findings although interictal EEG demonstrated left centro-parieto-temporal localized spike foci.

CONCLUSIONS

The focal ES of one lower limb, following treatment of ES in these two infants with WS, suggests the origin of the ES in the first case to be a neocortical focus involving the primary motor cortex representing the lower limb while that in the second case involves more widespread neocortical area with predominance in the same motor cortex as the first case.

Pediatric intractable epilepsy syndromes: reason for early surgical intervention

Drug-resistance in several childhood epilepsy syndromes is common, and these patients may tolerate epilepsy surgery. In this study, the surgical outcomes of 24 pediatric patients with various intractable epilepsy syndromes and three patients with tuberous sclerosis were examined at Xinqiao hospital between 1997 and 2004. The study included nine cases of Lennox-Gastaut syndrome, two cases of Rasmussen's syndrome, one case of Sturge-Weber syndrome, three cases of West syndrome, three cases of tuberous sclerosis and nine cases of mesial temporal lobe epilepsy syndrome. In each case, different surgical procedures were performed according to preoperative evaluation and ECoG. At an average of 4.5 years after surgery, 14 out of 27 patients (51.9%) had an Engel Class I outcome after surgery, and an additional eight patients (29.6%) had rare seizure (Engel ClassII). Three patients showed a significant decrease in seizure frequency (Engel Class III). The mean IQ increased from 61.4+/-12.2 to 75.0+/-11.0, and greater IQ increase was seen in patients with shorter seizure history and drug-resistance. Temporary complications were observed in four patients and there were no deaths. In conclusion, early surgical intervention in pediatric intractable epilepsy syndromes may results in a favorable outcome in a high percentage of cases and may provides an important opportunity to prevent irreversible decline in intelligence and disability.

Focal cortical malformations can show asymmetrically higher uptake on interictal fluorine-18 fluorodeoxyglucose positron emission tomography (PET)

Interictal fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) is a component of the presurgical evaluation of patients with medically intractable epilepsy, including patients with malformations of cortical development. The authors describe 3 cases of focal cortical malformations that displayed asymmetrically higher uptake on FDG-PET performed in the interictal state in patients undergoing evaluation for possible focal resection for refractory localization-related epilepsy. The evaluation included routine and prolonged video electroencephalography (EEG), magnetic resonance imaging (MRI), interictal FDG-PET with concurrent EEG, and single-photon emission computed tomography (SPECT). All 3 patients had focal cortical malformations on MRI corresponding to regions of asymmetrically higher uptake on FDG-PET. EEG confirmed that the FDG-PET studies were performed in the interictal state. The lesions included a large region of subcortical heterotopia in the right frontal lobe, a left temporal lobe dysplasia, and a region of subcortical heterotopia in the right occipital lobe. In both patients with subcortical heterotopia, there were other focal regions of cortical malformation that were not associated with abnormal or asymmetric uptake on FDG-PET. Previous reports describe decreased uptake on interictal PET in most cases of focal cortical malformations. Normal to increased uptake has been reported with band heterotopia. The authors demonstrate that other types of focal malformations of cortical development, including focal subcortical heterotopia and lobar dysplasia, can be associated with asymmetrically higher uptake on interictal FDG-PET.

Functional neuroimaging in the preoperative evaluation of children with drug-resistant epilepsy

FUNCTIONAL NEUROIMAGING: Although the primary imaging modality in the management of epilepsy is magnetic resonance imaging MRI, functional neuroimaging with positron-emission tomography (PET) and single photon emission computed tomography (SPECT) often provides complementary information and, in a number of situations, provides unique information that cannot be obtained with MRI. The most commonly used PET tracers used for epilepsy evaluation are 2-deoxy-2-[(18)F]fluoro-D: -glucose (FDG) and [(11)C]flumazenil (FMZ). Recently, interictal PET with alpha-[(11)C]methyl-L: -tryptophan was found to be highly specific for the epileptic focus and can differentiate between epileptogenic and nonepileptogenic lesions in the same patient (e.g., in patients with tuberous sclerosis).

DISCUSSION

In this review, we discuss clinical applications of these three PET tracers in drug-resistant temporal and extratemporal lobe epilepsy, selected epilepsy syndromes of childhood, lesional and nonlesional epilepsy, and the challenges of imaging secondary epileptic foci. A brief discussion of SPECT applications in epilepsy is also included. With further development of new tracers highly sensitive and specific for epileptogenic brain regions, the presurgical evaluation of refractory epilepsy will be greatly facilitated. Approximately 0.5 to 1.0% of the population suffer from epilepsy, of which 15-20% are intractable. Infants and children, whose seizures have a focal onset are refractory to anticonvulsants and are prolonged, tend to have the worst cognitive outcome [Meador KJ, Neurology 58 (Suppl 5):S21-S26, 2002]. Seizures themselves affect the developing brain and contribute to an adverse neurologic outcome (Holmes, Pediatric Neurology 33:1-110, 2005).

CONCLUSION

Therefore, in treating children with intractable epilepsy, it is important to consider seizure control and to give allowance for normal cognitive development.

Epilepsy in children

10.5 million children worldwide are estimated to have active epilepsy. Over the past 15 years, syndrome-oriented clinical and EEG diagnosis, and better aetiological diagnosis, especially supported by neuroimaging, has helped to clarify the diversity of epilepsy in children, and has improved management. Perinatal and postinfective encephalopathy, cortical dysplasia, and hippocampal sclerosis account for the most severe symptomatic epilepsies. Ion channel defects can underlie both benign age-related disorders and severe epileptic encephalopathies with a progressive disturbance in cerebral function. However, the reasons for age-related expression in children are not understood. Neither are the mechanisms whereby an epileptic encephalopathy originates. Several new drugs have been recently introduced but have provided limited therapeutic benefits. However, treatment and quality of life have improved because the syndrome-specific efficacy profile of drugs is better known, and there is heightened awareness that compounds with severe cognitive side-effects and heavy polytherapies should be avoided. Epilepsy surgery is an important option for a few well-selected individuals, but should be considered with great caution when there is no apparent underlying brain lesion.

The diagnostic value of initial video-EEG monitoring in children—Review of 1000 cases

OBJECTIVE

We retrospectively reviewed the clinical utility of initial video-EEG monitoring in a series of 1000 children suspected of epileptic disorders.

METHODS

The ages of patients (523 boys and 477 girls) ranged from 1 month to 17 years (median age: 7 years). The mean length of stay was 1.5 days (range: 1-10 days). Outcomes were classified as: 'useful-epileptic' (successful classification of epilepsy), 'useful-nonepileptic' (demonstration of nonepileptic habitual events), 'uneventful' (normal EEG without habitual events captured), and 'inconclusive' (inability to clarify the nature of habitual events with abnormal interictal EEG findings).

RESULTS

A total of 315 studies were considered 'useful-epileptic'; 219 'useful-nonepileptic'; 224 'uneventful'; 242 'inconclusive'. Longer monitoring was associated with higher rate of a study classified as 'useful-epileptic' in all age groups (Chi square test: p<0.001). In addition, longer monitoring was associated with lower rate of a study classified as 'inconclusive' in adolescences (p<0.001). Approximately half of the children with successful classification of epilepsy were assigned a specific diagnosis of epilepsy syndrome according to the International League Against Epilepsy (ILAE) classification. We found only 22 children with ictal EEG showing a seizure onset purely originating from a unilateral temporal region.

CONCLUSION

Video-EEG monitoring may fail to capture habitual episodes. To maximize the utility of studies in the future, a video-EEG monitoring longer than 3 days should be considered in selected children such as adolescences with habitual events occurring on a less than daily basis. We recognize a reasonable clinical utility of the current ILAE classification in the present study. It may not be common to identify children with pure unilateral temporal lobe epilepsy solely based on video-EEG monitoring.

Origin and propagation of epileptic spasms delineated on electrocorticography

PURPOSE

Ictal electrographic changes were analyzed on intracranial electrocorticography (ECoG) in children with medically refractory epileptic spasms to assess the dynamic changes of ictal discharges associated with spasms and their relation to interictal epileptiform activity and neuroimaging findings.

METHODS

We studied a consecutive series of 15 children (age 0.4 to 13 years; nine girls) with clusters of epileptic spasms recorded on prolonged intracranial subdural ECoG recordings, which were being performed for subsequent cortical resection, and in total, 62 spasms were analyzed by using quantitative methods.

RESULTS

Spasms were associated with either a "leading" spike followed by fast-wave bursts (type I: 42 events analyzed quantitatively) or fast-wave bursts without a "leading" spike (type II: 20 events analyzed quantitatively). Twenty-three of the 42 type I spasms but none of the 20 type II spasms were preceded by a focal seizure. A "leading" spike had a focal origin in all 42 type I spasms and involved the pre- or postcentral gyrus within 0.1 s in 37 of these spasms. A leading spike was associated with interictal spike activity >1/min in 40 of 42 type I spasms and originated within 2 cm from a positron emission tomography glucose hypometabolic region in all but two type I spasms. Failure to resect the cortex showing a leading spike was associated with poor surgical outcome (p = 0.01; Fisher's exact probability test). Fast-wave bursts associated with spasms involved neocortical regions extensively at least in two lobes within 1.28 s in all 62 spasms and involved the pre- or postcentral gyrus in 53 of 62 spasms.

CONCLUSIONS

Epileptic spasms may be triggered by a focal neocortical impulse in a subset of patients, and a leading spike, if present, might be used as a marker of the trigger zone for epileptic spasms. Rapidly emerging widespread fast-wave bursts might explain the clinical semiology of epileptic spasms.

Epilepsy surgery outcome in children with tuberous sclerosis complex evaluated with alpha-[11C]methyl-L-tryptophan positron emission tomography (PET)

Tuberous sclerosis complex is commonly associated with medically intractable seizures. We previously demonstrated that high uptake of alpha-[11C]methyl-L-tryptophan (AMT) on positron emission tomography (PET) occurs in a subset of epileptogenic tubers consistent with the location of seizure focus. In the present study, we analyzed the surgical outcome of children with tuberous sclerosis complex in relation to AMT PET results. Seventeen children (mean age 4.7 years) underwent epilepsy surgery, guided by long-term videoelectroencephalography (EEG) (including intracranial EEG in 14 cases), magnetic resonance imaging (MRI), and AMT PET. AMT uptake values of cortical tubers were measured using regions of interest delineated on coregistered MRI and were divided by the value for normal-appearing cortex to obtain an AMT uptake ratio. Based on surgical outcome data, tubers showing increased AMT uptake (uptake ratio greater than 1.00) were classified into three categories: (1) epileptogenic (tubers within an EEG-defined epileptic focus whose resection resulted in seizure-free outcome), (2) nonepileptogenic (tubers that were not resected but the patient became seizure free), or (3) uncertain (all other tubers). Increased AMT uptake was found in 30 tubers of 16 children, and 23 of these tubers (77%) were located in an EEG-defined epileptic focus. The tuber with the highest uptake was located in an ictal EEG onset region in each patient. Increased AMT uptake indicated an epileptic region not suspected by scalp EEG in four cases. Twelve children (71%) achieved seizure-free outcome (median follow-up 15 months). Based on outcome criteria, 19 of 30 tubers (63%) with increased AMT uptake were epileptogenic, and these tubers had significantly higher AMT uptake than the nonepileptogenic ones (P = .009). Tubers with at least 10% increase of AMT uptake (in nine patients) were all epileptogenic. Using a cutoff threshold of 1.02 for AMT uptake ratio provided an optimal accuracy of 83% for detecting tubers that needed to be resected to achieve a seizure-free outcome. The findings suggest that resection of tubers with increased AMT uptake is highly desirable to achieve seizure-free surgical outcome in children with tuberous sclerosis complex and intractable epilepsy. AMT PET can provide independent complementary information regarding the localization of epileptogenic regions in tuberous sclerosis complex and enhance the confidence of patient selection for successful epilepsy surgery.

Surgical treatment of epilepsy in children caused by focal cortical dysplasia

Focal cortical dysplasia (FCD) is a congenital disorder of neuronal migration that is increasingly recognized as a common cause of seizures in children, occurring in 20-30% of all surgically treated cases of epilepsy in the pediatric population. Advances in neuroimaging have contributed to recognition of FCD. We report 15 children (9 female, 6 male) with FCD and surgically treated intractable epilepsy. In 9 cases, a surgical strategy of anatomic (frameless stereotactic) grid placement and physiologic (electrocorticography) resection was employed. Postoperative MRI scans were obtained, the pathologic specimen was graded according to the Brannstrom system, and seizure outcome was defined using the Engel classification. There were no deaths and no permanent morbidity. After, on average, 4 years since treatment, 10 children are seizure free, 2 are 2A, 2 are 2B and 1 is 3A. Predictors of good outcome are an MRI-defined lesion and increased cortical disorganization (higher Brannstrom grade). Subtotal resection did not preclude a seizure-free outcome.

Dynamic cortical activity during spasms in three patients with West syndrome: a multichannel near-infrared spectroscopic topography study

PURPOSE

To investigate spatial and temporal cortical activity during clusters of naturally occurring epileptic spasms in patients with West syndrome (WS) by using multichannel near-infrared spectroscopy (mNIRS).

METHODS

Conventional magnetic resonance imaging (MRI) and interictal and ictal single-photon emission computed tomography (SPECT) were carried out in three patients with WS. Thereafter, cortical hemodynamics during naturally occurring epileptic spasms were measured by mNIRS with simultaneous video/electroencephalographic (EEG) monitoring.

RESULTS

Ictal SPECT revealed multiple hyperperfused areas within the cortex. With the use of mNIRS, an increase in regional cerebral blood volume (CBV) was observed in these areas, which is representative of cortical activation. The increase in CBV was accompanied by an increase in the concentrations of both oxy- and deoxyhemoglobin. The following heterogeneous regional changes in CBV during ictus were observed: (a) transient increases that were synchronized with spasms; (b) a gradual increase during an ictal event that fluctuated in synchrony with spasms; and (c) a combination of transient and gradual increases. An increase in regional CBV occurred in multiple areas that were activated either simultaneously or sequentially during an ictal event. Topographic changes in CBV were closely correlated with the phenotype of the spasm.

CONCLUSIONS

During ictal events, multiple cortical areas were activated simultaneously or sequentially. The pattern of cortical activation closely affected the phenotype of the spasm, which suggested that the cortex was involved in the generation of spasms.