Variation in neuroimaging and outcomes in patients with Sturge Weber syndrome Type III.

OBJECTIVES: Sturge Weber syndrome (SWS) is a neurovascular condition with an estimated incidence of 1 in 20,000 to 50,000 live births. SWS Types I and II involve cutaneous and ophthalmological findings, with neurological involvement in Type I. SWS Type III is exclusive to brain stigmata. Our study aims to describe the characteristics of brain MRI findings and report neuroradiological features with seizure and cognitive outcomes in patients with SWS Type III. METHODS: This is a retrospective case series examining the clinical, radiological, and cognitive characteristics of patients with SWS Type III referred to the SWS Clinic at Boston Children's Hospital. We analyzed brain MRI findings based on vascular and parenchymal features. Clinical and cognitive outcomes were based on a validated assessment tool in this population (Neuroscore). RESULTS: This dedicated case series of patients with Type III SWS from a single center identified ten patients. All patients had classic stigmata indicative of SWS. Two distinct radiological phenotypes were found, one characterized by more pronounced deep venous enlargement, and the other, with more pronounced parenchymal abnormalities. There was heterogeneity in seizure presentation and outcome. Earlier age of onset and seizures predict more severe outcomes, as seen in classic SWS. CONCLUSION: We could not find significant divergence in outcomes between patients with differing neuroimaging phenotypes. These results raise the question of whether the two distinct radiological phenotypes found in SWS Type III are reflective of different disease entities, with underlying genetic heterogeneity. These results suggest the need for larger, multi-center natural history studies.

Interictal Connectivity Revealed by Granger Analysis of Stereoelectroencephalography: Association With Ictal Onset Zone, Resection, and Outcome.

BACKGROUND: Stereoelectroencephalography (sEEG) facilitates electrical sampling and evaluation of complex deep-seated, dispersed, and multifocal locations. Granger causality (GC), previously used to study seizure networks using interictal data from subdural grids, may help identify the seizure-onset zone from interictal sEEG recordings. OBJECTIVE: To examine whether statistical analysis of interictal sEEG helps identify surgical target sites and whether surgical resection of highly ranked nodes correspond to favorable outcomes. METHODS: Ten minutes of extraoperative recordings from sequential patients who underwent sEEG evaluation were analyzed (n = 20). GC maps were compared with clinically defined surgical targets using rank order statistics. Outcomes of patients with focal resection/ablation with median follow-up of 3.6 years were classified as favorable (Engel 1, 2) or poor (Engel 3, 4) to assess their relationship with the removal of highly ranked nodes using the Wilcoxon rank-sum test. RESULTS: In 12 of 20 cases, the rankings of contacts (based on the sum of outward connection weights) mapped to the seizure-onset zone showed higher causal node connectivity than predicted by chance ( P ≤ .02). A very low aggregate probability ( P < 10 -18 , n = 20) suggests that causal node connectivity predicts seizure networks. In 8 of 16 with outcome data, causal connectivity in the resection was significantly greater than in the remaining contacts ( P ≤ .05). We found a significant association between favorable outcome and the presence of highly ranked nodes in the resection ( P < .05). CONCLUSION: Granger analysis can identify seizure foci from interictal sEEG and correlates highly ranked nodes with favorable outcome, potentially informing surgical decision-making without reliance on ictal recordings.

Infantile Hemiconvulsion-Hemiplegia and Epilepsy (IHHE) in a boy with tuberous sclerosis complex.

Tuberous sclerosis complex (TSC) is a rare autosomal dominant disease due to pathogenic variants in TSC1 or TSC2 genes. In the brain, TSC is associated with multiple cortical and subcortical malformations including tubers and abnormalities of radial neuronal migration. Approximately 80% of patients develop epilepsy in the first two years of life, most often focal seizures and infantile spasms. As with all seizure disorders, systemic illness and fever can trigger a seizure, and result in status epilepticus or even refractory status epilepticus. Infantile Hemiconvulsion-Hemiplegia and Epilepsy (IHHE) is considered a subcategory of new-onset refractory status epilepticus (NORSE) and presents with hemiclonic seizures in the setting of fever, unihemispheric brain imaging abnormality and hemiparesis. Here, we present an 18-month-old boy with TSC who developed IHHE. His extensive brain malformations and neuronal hyperexcitability in peri-tuberal tissue could have predisposed him to IHHE. In addition to these factors, we postulate that another prerequisite for IHHE is likely a genetic predisposition for an excessive inflammatory response that is yet to be elucidated.

Mortality in infantile spasms: A hospital-based study.

OBJECTIVE: To determine risk factors and causes for mortality during childhood in patients with infantile spasms (IS). We describe the overall goals of care for those who died. METHODS: This is a retrospective chart review of IS patients born between 2000 and 2011. We examined potential risk factors for mortality, including etiology, neurologic impairment, medication use, persistence of epileptic spasms, and comorbid systemic involvement (requirement for G-tube feedings, respiratory interventions). For patients who died, we describe cause of death and resuscitation status or end-of-life care measures. RESULTS: We identified 150 IS patients with median follow-up of 12 years. During the study period, 25 (17%) patients died, 13 before 5 years of age. Univariate analysis demonstrated that developmental delay, identifiable etiology, hormonal use for IS, persistence of epileptic spasms, polypharmacy with antiseizure medications, refractory epilepsy, respiratory system comorbidity, and the need for a G-tube were significant risk factors for mortality. In a multivariate analysis, mortality was predicted by persistence of epileptic spasms (odds ratio [OR] = 4.30, 95% confidence interval [CI] = 1.11-16.67, P = .035) and significant respiratory system comorbidity (OR = 12.75, 95% CI = 2.88-56.32, P = .001). Mortality was epilepsy-related in one-third of patients who died with sudden unexpected death in epilepsy (SUDEP), accounting for 88% of epilepsy-related deaths. Most deaths before age 5 years were related to respiratory failure, and SUDEP was less common (17%) whereas SUDEP was more common (45%) with deaths after 5 years. For the majority (67%) of patients with early mortality, an end-of-life care plan was in place (based on documentation of resuscitation status, comfort measures, or decision not to escalate medical care). SIGNIFICANCE: Mortality at our single-center IS cohort was 17%, and persistence of epileptic spasms and comorbid respiratory system disorders were the most important determinants of mortality. Early deaths were related to neurological impairments/comorbidities. SUDEP was more common in children who died after 5 years of age than in those who died younger than 5 years.

Neuroimaging in Pediatric Epilepsy.

Pediatric epilepsy presents with various diagnostic challenges. Recent advances in neuroimaging play an important role in the diagnosis, management and in guiding the treatment of pediatric epilepsy. Structural neuroimaging techniques such as CT and MRI can identify underlying structural abnormalities associated with epileptic focus. Functional neuroimaging provides further information and may show abnormalities even in cases where MRI was normal, thus further helping in the localization of the epileptogenic foci and guiding the possible surgical management of intractable/refractory epilepsy when indicated. A multi-modal imaging approach helps in the diagnosis of refractory epilepsy. In this review, we will discuss various imaging techniques, as well as aspects of structural and functional neuroimaging and their application in the management of pediatric epilepsy.

Compound heterozygosity with PRRT2: Pushing the phenotypic envelope in genetic epilepsies.

PRRT2 pathogenic variants have been described in benign familial infantile epilepsy, episodic ataxia, paroxysmal kinesigenic dyskinesia, and hemiplegic migraines. We describe a patient with compound heterozygous variants, infantile epilepsy with status epilepticus, paroxysmal dyskinesia and episodic ataxia. Testing revealed a pathogenic PRRT2 duplication (c.649dupC), and a likely pathogenic missense variant (c.916G>A). His presentation meets the severe phenotypic category with a combination of at least 3 neurological symptoms: seizures and status epilepticus, prolonged episodic ataxia, and paroxysmal dyskinesia. This further expands the clinical findings related to PRRT2, and suggests that compound heterozygous variants could confer a severe phenotype.

Yield of Emergent Neuroimaging in Patients With Sturge-Weber Syndrome Presenting With Acute Neurologic Symptoms.

BACKGROUND/AIMS: Seizures, strokelike episodes, and headaches are common complications in patients with Sturge-Weber syndrome. Based on our experience, we hypothesized that patients with Sturge-Weber syndrome have frequent urgent neuroimaging studies when presenting acutely to the emergency department. In this study, we aimed to determine the incidence of acute imaging studies in this patient population and to evaluate the prevalence of findings such as acute intracranial hemorrhagic or ischemic strokes. METHODS: To determine the frequency and yield of brain imaging, we conducted a retrospective chart analysis in patients with Sturge-Weber syndrome who presented to Boston Children's Hospital with acute neurologic symptoms between 1996 and 2016. RESULTS: We reviewed 136 encounters of patients with Sturge-Weber syndrome. In 73 of 136 encounters (53.7%), patients underwent a total of 89 imaging studies, consisting of 47 head computed tomographies (CTs) and 42 brain magnetic resonance images (MRIs). Twenty-two percent of patients imaged underwent both CT and MRI scanning of the brain. Patients with strokelike episodes or headaches were more likely to be imaged compared to patients presenting with seizures (89.7% and 100% vs 34.4%, respectively). None of the neuroimaging studies showed acute hemorrhagic or ischemic strokes. CONCLUSIONS: Acute neurologic manifestations of Sturge-Weber syndrome frequently lead to urgent neuroimaging. In our cohort, there was no imaging evidence of acute hemorrhagic or ischemic strokes. In addition, emergent imaging in patients presenting with breakthrough seizures did not result in meaningful changes in management.

Transient regional cerebral hypoperfusion during a paroxysmal hemiplegic event in GLUT1 deficiency syndrome.

GLUT1 deficiency syndrome (GLUT1DS) is a well described neurometabolic disorder that results from impaired glucose transport into the central nervous system. GLUT1DS classically presents with infantile-onset epilepsy, progressive microcephaly, developmental delay, ataxia, dystonia, and spasticity, but a minority of patients may manifest with paroxysmal non-epileptic phenomena including hemiparesis (Wang et al., 2002). We report for the first time cerebral perfusion changes during an acute episode of hemiparesis in a 9 year old child with GLUT1DS. The patient presented as a code stroke with her second episode of acute-onset left hemiparesis and altered mental status. Emergency MRI of brain demonstrated normal diffusion-weighted imaging, but arterial spin label perfusion weighted imaging (ASL-PWI) showed regional hypoperfusion of the right cerebral hemisphere and magnetic resonance angiography (MRA) revealed distally restricted flow related enhancement in the right MCA. The patient's deficits resolved entirely within several hours from onset. Repeat MRI one month later was normal. Our report suggests that GLUT1DS-related hemiplegic events are associated with transient lateralized cerebrovascular hypoperfusion similar to that described in hemiplegic migraine and other pediatric stroke mimics. The underlying pathophysiology for this phenomenon in GLUT1DS is not known, but may relate to cortical energy failure or abnormal cerebral microvasculature.

Response to clobazam in continuous spike-wave during sleep.

AIM: To evaluate the efficacy of clobazam treatment in reducing epileptiform discharges and modifying neuropsychological function in continuous spike-wave during slow wave sleep. METHOD: We performed a prospective clinical trial in patients with continuous spike-wave during sleep aged 4 to 10 years. Patients underwent neuropsychological assessment and overnight electroencephalographic monitoring before treatment, and subsequent repeat assessment and overnight electroencephalographic monitoring 3 months after treatment. Treatment consisted of 1mg/kg clobazam up to a maximum dose of 30mg during the first night, followed by 0.5mg/kg nightly for 3 months. RESULTS: Nine patients completed the study and had pre- and post-neuropsychological evaluation. There was a qualitative reduction in median (p25 -p75 ) spike percentage after 3 months (72.2 [68.0-75.8] vs 32.7 [4.7-81.7]). There were no marked changes in median (p25 -p75 ) IQ comparing pre- and post-clobazam treatment (80.0 [74.0-88.0] vs 80.0 [67.0-89.0]). There was a qualitative increase in Verbal IQ (83.0 [69.0-92.0] vs 95.0 [83.0-99.0]) and a qualitative decrease in Non-verbal IQ (84.0 [74.0-87.0] vs 71.0 [60.0-84.0]). INTERPRETATION: Qualitative improvements in epileptiform activity and cognition occurred in patients treated with clobazam for 3 months and the relationship between epileptiform activity and cognitive outcome should be studied in larger studies. WHAT THIS PAPER ADDS: Verbal IQ in patients with continuous spike-wave during sleep improved following short-term treatment with clobazam. Other neuropsychological improvements were observed, but varied by patient. Cognitive improvement was observed despite some worsening of epileptiform discharges.

Systemic Manifestations in Pyridox(am)ine 5'-Phosphate Oxidase Deficiency.

OBJECTIVE: Pyridoxine is converted to its biologically active form pyridoxal-5-phosphate (P5P) by the enzyme pyridox(am)ine 5'-phosphate oxidase and serves as a cofactor in nearly 200 reactions in the central nervous system. Pyridox(am)ine 5'-phosphate oxidase deficiency leads to P5P dependent epilepsy, typically a neonatal- or infantile-onset epileptic encephalopathy treatable with P5P or in some cases, pyridoxine. Following identification of retinopathy in a patient with pyridox(am)ine 5'-phosphate oxidase deficiency that was reversible with P5P therapy, we describe the systemic manifestations of pyridox(am)ine 5'-phosphate oxidase deficiency. METHODS: A series of six patients with homozygous mutations of PNPO, the gene coding pyridox(am)ine 5'-phosphate oxidase, were evaluated in our center over the course of two years for phenotyping of neurological and systemic manifestations. RESULTS: Five of six were born prematurely, three had anemia and failure to thrive, and two had elevated alkaline phosphatase. A movement disorder was observed in two children, and a reversible retinopathy was observed in the most severely affected infant. All patients had neonatal-onset epilepsy and were on a continuum of developmental delay to profound encephalopathy. Electroencephalographic features included background slowing and disorganization, absent sleep features, and multifocal and generalized epileptiform discharges. All the affected probands carried a homozygous PNPO mutation (c.674 G>T, c.686 G>A and c.352G>A). CONCLUSION: In addition to the well-described epileptic encephalopathy, pyridox(am)ine 5'-phosphate oxidase deficiency causes a range of neurological and systemic manifestations. A movement disorder, developmental delay, and encephalopathy, as well as retinopathy, anemia, and failure to thrive add to the broadening clinical spectrum of P5P dependent epilepsy.

Genetics and genotype-phenotype correlations in early onset epileptic encephalopathy with burst suppression.

OBJECTIVE: We sought to identify genetic causes of early onset epileptic encephalopathies with burst suppression (Ohtahara syndrome and early myoclonic encephalopathy) and evaluate genotype-phenotype correlations. METHODS: We enrolled 33 patients with a referral diagnosis of Ohtahara syndrome or early myoclonic encephalopathy without malformations of cortical development. We performed detailed phenotypic assessment including seizure presentation, electroencephalography, and magnetic resonance imaging. We confirmed burst suppression in 28 of 33 patients. Research-based exome sequencing was performed for patients without a previously identified molecular diagnosis from clinical evaluation or a research-based epilepsy gene panel. RESULTS: In 17 of 28 (61%) patients with confirmed early burst suppression, we identified variants predicted to be pathogenic in KCNQ2 (n = 10), STXBP1 (n = 2), SCN2A (n = 2), PNPO (n = 1), PIGA (n = 1), and SEPSECS (n = 1). In 3 of 5 (60%) patients without confirmed early burst suppression, we identified variants predicted to be pathogenic in STXBP1 (n = 2) and SCN2A (n = 1). The patient with the homozygous PNPO variant had a low cerebrospinal fluid pyridoxal-5-phosphate level. Otherwise, no early laboratory or clinical features distinguished the cases associated with pathogenic variants in specific genes from each other or from those with no prior genetic cause identified. INTERPRETATION: We characterize the genetic landscape of epileptic encephalopathy with burst suppression, without brain malformations, and demonstrate feasibility of genetic diagnosis with clinically available testing in >60% of our cohort, with KCNQ2 implicated in one-third. This electroclinical syndrome is associated with pathogenic variation in SEPSECS. Ann Neurol 2017;81:419-429.

Sturge-Weber Syndrome: Brain Magnetic Resonance Imaging and Neuropathology Findings.

BACKGROUND: We describe the brain magnetic resonance imaging (MRI) abnormalities and neuropathologic findings of patients with Sturge-Weber syndrome and medically refractory epilepsy. METHODS: We reviewed the clinical features, preoperative MRI studies, and pathologic findings of all patients with Sturge-Weber syndrome who underwent excisional surgery for intractable epilepsy at Boston Children's Hospital between 1993 and 2011. RESULTS: Eleven patients (male/female = 4/7) with Sturge-Weber syndrome were identified who underwent surgery for intractable epilepsy (mean age 13 ± 6.2 months), including hemispherectomy (n = 10) and focal cortical resection (n = 1). Mean age at seizure onset was 15 ± 11 weeks. Fifty-five percent (n = 6) of patients exhibited two different types of seizures, and 18% (n = 2) had three types of seizures. Focal clonic seizures were the most common type, occurring in nine patients; apnea was the second most common, occurring in four patients. Brain MRIs were reviewed in five patients. Histopathologic examination revealed varied degrees of cortical morphologic anomaly in seven of 11 patients. Overall, there were no abnormalities in the MRIs that corresponded directly with the pathologic findings except in one patient with polymicrogyria. CONCLUSIONS: In spite of pathologic findings of cortical anomalies in varied degrees, these findings could not be readily detected on brain MRIs. The failure to detect focal cortical dysplasia on MRIs may be attributable to the subtle microscopic nature of the abnormalities; in some of the older individuals, the imaging studies available for review were done during an advanced stage of the disease.

Utility of initial EEG in first complex febrile seizure.

OBJECTIVE: The risk of developing epilepsy following febrile seizures (FS) varies between 2% and 10%, with complex febrile seizures (CFS) having a higher risk. We examined the utility of detected epileptiform abnormalities on the initial EEG following a first CFS in predicting subsequent epilepsy. METHODS: This was a retrospective study of consecutive patients (ages 6-60 months) who were neurologically healthy or mildly delayed, seen in the ED following a first CFS and had both an EEG and minimum of 2-year follow-up. Data regarding clinical characteristics, EEG report, development of subsequent epilepsy, and type of epilepsy were collected. Established clinical predictors for subsequent epilepsy in children with FS and EEG status were evaluated for potential correlation with the development of subsequent epilepsy. Sensitivity, specificity, and positive and negative predictive values of an abnormal EEG (epileptiform EEG) were calculated. RESULTS: A group of 154 children met our inclusion criteria. Overall, 20 (13%) children developed epilepsy. The prevalence of epilepsy was 13% (CI 8.3-19.6%). Epileptiform abnormalities were noted in 21 patients (13.6%), EEG slowing in 23 patients (14.9%), and focal asymmetry in six (3.8%). Epileptiform EEGs were noted in 20% (4/20) of patients with epilepsy and 13% (17/134) of patients without epilepsy (p=0.48). At an estimated risk of subsequent epilepsy of 10% (from population-based studies of children with FS), we determined that the PPV of an epileptiform EEG for subsequent epilepsy was 15%. None of the clinical variables (presence of more than 1 complex feature, family history of epilepsy, or status epilepticus) predicted epilepsy. CONCLUSIONS: An epileptiform EEG was not a sensitive measure and had a poor positive predictive value for the development of epilepsy among neurologically healthy or mildly delayed children with a first complex febrile seizure. The practice of obtaining routine EEG for predicting epilepsy after the first CFS needs clarification by well-defined prospective studies.

Clinical and Neuroimaging Profile of Children with Lesions in the Corpus Callosum.

PURPOSE: T2-hyperintense signal changes in corpus callosum (CC) have been described in epilepsy and encephalitis/encephalopathy. Little is known about their pathophysiology. The aim of this study was to examine the clinical presentation and evolution of CC lesions and relationship to seizures. METHODS: We identified 12 children among 29,634 patients from Radiology Database. We evaluated following characteristics: seizures and accompanying medical history, antiepileptic drug usage, presenting symptoms, and radiological evolution of lesions. RESULTS: CC lesions were seen in patients with prior diagnosis of epilepsy (n = 5) or in those with new onset seizures (n = 3), or with encephalitis/encephalopathy without history of seizures (n = 4). Seizure clustering or disturbances of consciousness were the main presenting symptoms. No relationship was observed between CC lesion and AEDs. On imaging, ovoid lesions at presentation resolved on follow up imaging and linear lesions persisted. DTI showed that the fibers passing through splenial lesions originated from the posterior parietal cortex and occipital cortex bilaterally. CONCLUSION: In patients with seizures, no clear relationship was demonstrated between seizure characteristics or AED use with CC lesions. Ovoid lesions resolved and may have different pathophysiologic mechanism when compared to linear lesions that persisted.

Surgery for intractable epilepsy due to unilateral brain disease: a retrospective study comparing hemispherectomy techniques.

BACKGROUND: Hemispherectomy is a surgical procedure used to treat medically intractable epilepsy in children with severe unilateral cortical disease secondary to acquired brain or congenital lesions. The major surgical approaches for hemispherectomy are anatomic hemispherectomy, traditional functional hemispherectomy, and peri-insular hemispherotomy. We describe the epilepsy outcome, including the need for reoperation, after hemispherectomy in patients with brain malformations or acquired brain lesions who underwent hemispherectomy for refractory epilepsy. METHODS: We conducted a retrospective observational study at Children's Hospital Boston. Cases were ascertained from a research database of patients who underwent epilepsy surgery from 1997 to 2011. Data were obtained from electronic medical records and office charts. Outcome after surgery was defined as improvement in seizures (quantity and severity) represented by the Engel classification score measured at last follow-up, with a minimum of 12 months of follow-up. The need for reoperation for completion of hemispheric disconnection. We also examined whether placement of ventriculoperitoneal shunt was required after hemispherectomy was a secondary outcome. RESULTS: We identified 36 patients who underwent hemispherectomy for severe, medically intractable epilepsy. Group 1 (n = 14) had static acquired lesions, and group 2 (n = 22) had malformations of cortical development. Mean age at surgery for group 1 was 9 years (S.D. 5.5) and 2.77 years for group 2 (S.D. 4.01; P < 0.001). The seizure outcome was good in both groups (Engel score I for 25, II for three, III for six, and IV for two patients) and did not differ between the two groups. In group 1, five patients underwent anatomic hemispherectomy (one had prior focal resection), four underwent functional hemispherectomy, and five underwent peri-insular hemispherotomy; none required a second procedure. In group 2, a total of 14 patients had anatomic hemispherectomy (of these, three had had limited prior focal resection), five had functional hemispherectomy, and three had peri-insular hemispherotomy. Among the patients in group 2 who had had functional hemispherectomy, one required reoperation to complete the disconnection and one required peri-insular hemispherotomy because of persistent seizures. In group 1, three patients underwent a ventriculoperitoneal shunt, and from these patients two underwent anatomic hemispherectomy and one had functional hemispherectomy. In group 2, 12 patients had ventriculoperitoneal shunt, and all of them had anatomic hemispherectomy as a first or second procedure. CONCLUSION: Seizure outcome after hemispherectomy is good in patients with acquired lesions and with developmental malformations. Although the seizure outcome was similar in the three procedures, the complication rate was higher with anatomic hemispherectomy than with the more recent functional hemispherectomy and peri-insular hemispherotomy. The group with cortical malformations generally had surgery at a younger age; two patients with malformations of cortical development who underwent functional hemispherectomy required second surgeries. The need for reoperation in these cases may reflect the anatomic complexity of developmental hemispheric malformations, which may lead to incomplete disconnection.

Safety and retention rate of rufinamide in 300 patients: a single pediatric epilepsy center experience.

OBJECTIVE: Reports of studies evaluating rufinamide as an add-on therapy in children and adolescents with refractory epilepsy are restricted to a few publications. Prospective multicenter studies including children and adults have yielded important information about several types of epilepsies and syndromes. We evaluated the use of rufinamide in a single pediatric center with a large cohort and long-term follow-up period. METHODS: We retrospectively included patients taking rufinamide from November 2008 to March 2013. Response was defined by a seizure reduction of ≥50% compared to baseline. RESULTS: Three hundred patients with a median age of 9.1 years (range 0.4-29.6 years) were reviewed. Median follow-up was 9 months (range 1-37 months). Epilepsy etiology was classified as genetic (23.7%), structural/metabolic (41%), and unknown cause (35.3%). Overall, rufinamide treatment led to a median seizure frequency reduction of 59.2% from responders to baseline. Seizure reduction was greater in patients with genetic etiology compared to structural/metabolic (66.2% vs. 45.5% responders, p = 0.005). Rufinamide was discontinued in 110 (36.7%) of 300 patients: 63 (21%) due to unsatisfactory response, 47 (15.7%) due to side effects, and in 18 (6%) of those due to both. Most common adverse effects were sleepiness, vomiting, mood changes, nausea, and loss of appetite. Median time to loss of efficacy was 11.6 months (range 3-28 months). SIGNIFICANCE: Rufinamide provides satisfactory seizure reduction as an adjunctive treatment in refractory epilepsy. Results need to be interpreted in the setting of data acquisition, including inherent biases of retrospective studies. Patients with a known genetic etiology may have better responses than patients with structural/metabolic etiology.

Copy number variation plays an important role in clinical epilepsy.

OBJECTIVE: To evaluate the role of copy number abnormalities detectable using chromosomal microarray (CMA) testing in patients with epilepsy at a tertiary care center. METHODS: We identified patients with International Classification of Diseases, ninth revision (ICD-9) codes for epilepsy or seizures and clinical CMA testing performed between October 2006 and February 2011 at Boston Children's Hospital. We reviewed medical records and included patients who met criteria for epilepsy. We phenotypically characterized patients with epilepsy-associated abnormalities on CMA. RESULTS: Of 973 patients who had CMA and ICD-9 codes for epilepsy or seizures, 805 patients satisfied criteria for epilepsy. We observed 437 copy number variants (CNVs) in 323 patients (1-4 per patient), including 185 (42%) deletions and 252 (58%) duplications. Forty (9%) were confirmed de novo, 186 (43%) were inherited, and parental data were unavailable for 211 (48%). Excluding full chromosome trisomies, CNV size ranged from 18kb to 142Mb, and 34% were >500kb. In at least 40 cases (5%), the epilepsy phenotype was explained by a CNV, including 29 patients with epilepsy-associated syndromes and 11 with likely disease-associated CNVs involving epilepsy genes or "hotspots." We observed numerous recurrent CNVs including 10 involving loss or gain of Xp22.31, a region described in patients with and without epilepsy. INTERPRETATION: Copy number abnormalities play an important role in patients with epilepsy. Because the diagnostic yield of CMA for epilepsy patients is similar to the yield in autism spectrum disorders and in prenatal diagnosis, for which published guidelines recommend testing with CMA, we recommend the implementation of CMA in the evaluation of unexplained epilepsy.

Clobazam: effect on frequency of seizures and safety profile in different subgroups of children with epilepsy.

BACKGROUND: Clobazam has been used in clinical practice as an adjunctive treatment for diverse seizure types and epilepsy syndromes. We evaluated the efficacy and safety of clobazam in a large sample of patients with refractory epilepsy at a tertiary pediatric center. METHODS: We retrospectively reviewed patients treated with clobazam between January 2001 and July 2013 who had a follow-up visit at least one month after starting clobazam. Response was defined as ≥50% reduction in seizure frequency compared with baseline seizure frequency during the 3 months before the introduction of clobazam. We examined the relationship between dose range and response rate. RESULTS: Four-hundred twenty-five patients were prescribed clobazam, of whom 300 (median age 9.1 years, interquartile range 4.7-13.3 years) had follow-up data greater than 1 month. Median follow-up was 5 months (interquartile range 3-11 months). Response to treatment with clobazam was observed in 203 of 300 (67.7%) patients, of whom 84 (28%) became seizure-free. The median starting dose was 0.2 (interquartile range 0.13-0.33) mg/kg/day with a target dose of 0.48 (0.26-0.80) mg/kg/day. Twenty-seven (9%) patients discontinued clobazam, 16 (59.3%) because adverse effects, 10 (37%) because of a lack of efficacy, and one (3.7%) because of a combination of adverse effects and lack of efficacy. The most common adverse effects were tiredness in 44 of 300 (14.6%) and mood or behavioral changes in 23 (7.7%). CONCLUSIONS: Clobazam is a well-tolerated antiepileptic drug with good response rates in pediatric patients with refractory epilepsy.

Electrode localization for planning surgical resection of the epileptogenic zone in pediatric epilepsy.

PURPOSE: In planning for a potentially curative resection of the epileptogenic zone in patients with pediatric epilepsy, invasive monitoring with intracranial EEG is often used to localize the seizure onset zone and eloquent cortex. A precise understanding of the location of subdural strip and grid electrodes on the brain surface, and of depth electrodes in the brain in relationship to eloquent areas is expected to facilitate pre-surgical planning. METHODS: We developed a novel algorithm for the alignment of intracranial electrodes, extracted from post-operative CT, with pre-operative MRI. Our goal was to develop a method of achieving highly accurate localization of subdural and depth electrodes, in order to facilitate surgical planning. Specifically, we created a patient-specific 3D geometric model of the cortical surface from automatic segmentation of a pre-operative MRI, automatically segmented electrodes from post-operative CT, and projected each set of electrodes onto the brain surface after alignment of the CT to the MRI. Also, we produced critical visualization of anatomical landmarks, e.g., vasculature, gyri, sulci, lesions, or eloquent cortical areas, which enables the epilepsy surgery team to accurately estimate the distance between the electrodes and the anatomical landmarks, which might help for better assessment of risks and benefits of surgical resection. RESULTS: Electrode localization accuracy was measured using knowledge of the position of placement from 2D intra-operative photographs in ten consecutive subjects who underwent intracranial EEG for pediatric epilepsy. Average spatial accuracy of localization was 1.31 ± 0.69 mm for all 385 visible electrodes in the photos. CONCLUSIONS: In comparison with previously reported approaches, our algorithm is able to achieve more accurate alignment of strip and grid electrodes with minimal user input. Unlike manual alignment procedures, our algorithm achieves excellent alignment without time-consuming and difficult judgements from an operator.