A follow-up study of intractable seizures in childhood

Epilepsy and Encephalopathy

BACKGROUND

Epilepsy encompasses more than the predisposition to unprovoked seizures. In children, epileptic activity during (ictal) and between (interictal) seizures has the potential to disrupt normal brain development. The term "epileptic encephalopathy (EE)" refers to the concept that such abnormal activity may contribute to cognitive and behavioral impairments beyond that expected from the underlying cause of the epileptic activity.

METHODS

In this review, we survey the concept of EE across a diverse selection of syndromes to illustrate its broad applicability in pediatric epilepsy. We review experimental evidence that provides mechanistic insights into how epileptic activity has the potential to impact normal brain processes and the development of neural networks. We then discuss opportunities to improve developmental outcomes in epilepsy now and in the future.

RESULTS

Epileptic activity in the brain poses a threat to normal physiology and brain development.

CONCLUSION

Until we have treatments that reliably target and effectively treat the underlying causes of epilepsy, a major goal of management is to prevent epileptic activity from worsening developmental outcomes.

Risk factors and outcome of epilepsy in adults with cerebral palsy or intellectual disability

INTRODUCTION

Epilepsy is found in 10-60% of individuals with cerebral palsy (CP) and 5.5-35% with intellectual disability (ID). However, little is known about the long-term evolution of epilepsy among adults. The aim of the study is to describe the factors associated with epilepsy and its outcome in a population of adults with CP or ID.

METHODS

This retrospective study reviewed the medical records of 306 individuals with CP/ID. All individuals underwent neurological, psychiatric, and neuropsychological follow-ups.

RESULTS

In the cohort, 72.5% of the individuals had a CP diagnosis, with a mean age of 36.4 years (IQR 24.0-46.0). Epilepsy was present in 55.6% of the individuals and was associated with CP (p < 0.01), spastic subtype (p < 0.01), a higher degree of ID (p < 0.01), hemorrhagic and congenital malformation etiologies (p 0.011), abnormal neuroimaging (p < 0.01), and worse scores on motor and communication scales (p < 0.01). Drug-resistant epilepsy (DRE) (22.4%) was associated with higher scores on motor scales (p < 0.01). Additionally, 42.3% of the individuals who attempted antiseizure medication (ASM) withdrawal experienced recurrence, which was associated with epileptic activity on the electroencephalogram (EEG) (p 0.004).

CONCLUSIONS

Epilepsy is a common comorbidity in adults with CP or ID and is associated with greater brain damage and a more severe phenotype. Seizure recurrence after ASM withdrawal occurred in half of the individuals and was associated with epileptic activity on the EEG.

Pentoxifylline prevents epileptic seizure via modulating HMGB1/RAGE/TLR4 signalling pathway and improves memory in pentylenetetrazol kindling rats

Epilepsy is a chronic widely prevalent neurologic disorder, affecting brain functions with a broad spectrum of deleterious consequences. High mobility group box1 (HMGB1) is a nuclear non-histone protein that targets vital cell receptor of toll-like receptor 4 (TLR4) and advanced glycation end products (RAGE). HMGB1 mediated TLR4/RAGE cascade has been scored as a key culprit in neuroinflammatory signalling that critically evokes development of impaired cognition and epilepsy. The current study aimed to investigate the neuroprotective effect of pentoxifylline (PTX) on pentylenetetrazol (PTZ)-kindling rats by its anti-inflammatory/antioxidant capacity and its impact on memory and cognition were investigated, too. PTZ was intraperitoneally injected 35 mg/kg, every 48 h, for 14 doses, to evoke kindling model. Phenytoin (30 mg/kg, i.p.) and PTX (60 mg/kg, i.p.) or their combination were given once daily for 27 days. PTX treatment showed a statistically significant effect on behavioural, histopathological and neurochemical analysis. PTX protected the PTZ kindling rats from epileptic seizures and improved memory and cognitive impairment through the Morris water maze (MWM) test. Furthermore, PTX reversed PTZ hippocampal neuronal loss by decreasing protein expression of amyloid-β peptide (Aβ), Tau and β site-amyloid precursor protein cleavage enzyme 1 (BACE1), associated with a marked reduction in expression of inflammatory mediators such as HMGB1, TL4, and RAGE proteins. Furthermore, PTX inhibited hippocampal apoptotic caspase 1 protein, total reactive oxygen species (TROS) along with upregulated erythroid 2-related factor 2 (Nrf2) content. In conclusion, PTX or its combination with phenytoin represent a promising drug to inhibit the epilepsy progression via targeting the HMGB1/TLR4/RAGE signalling pathway.

Efficacy of low glycemic index diet therapy (LGIT) in children aged 2-8 years with drug-resistant epilepsy: A randomized controlled trial

BACKGROUND

A classic ketogenic diet, even though effective in children with drug-resistant epilepsy is not tolerated well by them and cumbersome to prepare. Low glycemic index therapy (LGIT), the least restrictive with minimal adverse effects among ketogenic dietary therapies has been proven effective in uncontrolled trials, but a placebo-controlled trial in this regard is still lacking.

METHODS

In this open-label randomized controlled study, we randomized children above age two years with drug-resistant epilepsy into two groups (LGIT and control groups). Patients in the LGIT group received an add-on low glycemic index diet for 3 months along with the ongoing antiepileptic drugs and the patients in the control group did not receive any dietary intervention. Seizure frequency was assessed from the seizure diary maintained by the parents. Diet compliance was assessed using the diet diary that was maintained by the parents for three days just before the scheduled monthly visits of the patients.

RESULTS

Forty children with drug-refractory epilepsy (20 in each group) were enrolled. While 6/20 children in the LGIT arm have >50 % reduction in seizure frequency, none achieved this in the control arm (p = 0.02). The overall compliance with the low glycemic diet in the intervention group was 88.5 %. Out of six responders to LGIT, one child achieved seizure freedom and one achieved >90 % seizure reduction. Five continued LGIT further for a median duration of 8 months (range-4-12 months) successfully. The number needed to treat for more than 50 % seizure reduction was 3 and for more than 90 % seizure reduction was 10. The mean frequency of seizures for the intervention and control groups at three months of follow-up was not significantly different (p = 0.16), but the change in seizure frequency as compared to baseline was better in the intervention arm (p = 0.01). Three patients in the LGIT arm had non-serious adverse events (lethargy in two, vomiting in one).

CONCLUSION

In children aged 2-8 years with drug-refractory epilepsy, the administration of LGIT along with ongoing anti-seizure medications (ASM) is more efficacious in reducing seizure frequency as compared to ASM alone.

Assessing risk: Characterizing language performance in pediatric patients with intractable epilepsy pre- and post-surgical resection

Neuropsychologists play an important role in assessing risk for post-surgical cognitive decline in pediatric patients with medically refractory epilepsy. Families, neurologists, and neurosurgeons are particularly concerned about the possibility for language decline for patients with a dominant, most often left, hemisphere epileptic focus and planned surgical resection. This study aims to describe language functioning in pediatric epilepsy patients following resection and evaluate the accuracy of a clinical approach of assessing risk. This study proposes a risk assessment method that considers a patient's pattern of lateralized dysfunction across cognitive domains, suspected neuroanatomical reorganization of language functions, and planned site of resection. Pediatric patients (N = 47) were dichotomized as being at minimal risk or at greater risk for post-surgical language decline based on the proposed risk assessment method. Retrospective chart review was utilized to obtain neuropsychological (Boston Naming Test and Weschler Vocabulary subtest) and clinical variables of interest. Patients in the minimal risk group demonstrated significantly improved BNT scores at post-surgery. Most patients remained stable in their Vocabulary knowledge. The proposed risk assessment method correctly classified patients 77% of the time based on BNT performance. Cluster analysis examining the individual components of the proposed method revealed three distinct patient subgroups. Clinical implications are discussed.

Unanticipated improvement in seizure control in drug-resistant epilepsy- real world observations

OBJECTIVES

To determine the clinical features and anti-seizure medication (ASM) strategies associated with an unanticipated substantial improvement in seizure control in patients with drug-resistant epilepsy (DRE).

METHODS

This retrospective analysis of patients attending a tertiary care epilepsy clinic between 2008 and 2017 identified all patients with active DRE (at least 1 seizure per month for 6 months, despite treatment with 2 different ASMs). All treatment interventions were recorded from when DRE was first identified to the end of the study. The primary end points were seizure freedom or meaningful reduction in seizure frequency (greater than 75 %) sustained for at least 12 months after a treatment intervention.

RESULTS

Three hundred and twenty-two patients were included in the analysis. Overall, 10 % became seizure free following ASM adjustment and an additional 10 % had a greater than 75 % improvement in seizure control (median follow-up, 4 years). An ASM introduction was ten times more likely than an ASM dose increase to improve seizure control. Combined focal and generalized epilepsy, intellectual disability and prior treatment with more than 5 ASMs were more frequently observed in those with continued pharmacoresistance. ASM responders were more likely to have primary generalized epilepsy. Rational polytherapy (combining ASMs with different mechanisms of action) was almost ubiquitous amongst ASMs responders (95 % taking at least 2 drugs with different mechanistic targets). Of the ASM additions that heralded improved seizure control, 85 % were maintained at submaximal doses.

CONCLUSIONS

This retrospective analysis of a large number of 'real-world' patients provides evidence to persist with ASM trials in DRE. Early rotation of ASMs if a clinical response is not observed at a substantial dose and rational ASM polytherapy may yield better clinical outcomes in patients with DRE, although a prospective study would need to be conducted to validate these findings.

Cognitive functioning after epilepsy surgery in children with mild malformation of cortical development and focal cortical dysplasia

Mild malformation of cortical development (mMCD) and focal cortical dysplasia (FCD) subtypes combined are by far the most common histological diagnoses in children who undergo surgery as treatment for refractory epilepsy. In patients with refractory epilepsy, a substantial burden of disease is due to cognitive impairment. We studied intelligence quotient (IQ) or developmental quotient (DQ) values and their change after epilepsy surgery in a consecutive series of 42 children (median age at surgery: 4.5, range: 0-17.0 years) with refractory epilepsy due to mMCD/FCD. Cognitive impairment, defined as IQ/DQ below 70, was present in 51% prior to surgery. Cognitive impairment was associated with earlier onset of epilepsy, longer epilepsy duration, and FCD type I histology. Clinically relevant improvement of ≥10 IQ/DQ points was found in 24% of children and was related to the presence of presurgical epileptic encephalopathy (EE). At time of postsurgical cognitive testing, 59% of children were completely seizure-free (Engel 1A). We found no association between cognitive outcome and seizure or medication status at two years of follow-up. Epilepsy surgery in children with mMCD or FCD not only is likely to result in complete and continuous seizure freedom, but also improves cognitive function in many.

A Retrospective Analysis of the Long-Term Outcome of Drug-Resistant Epilepsy in Children Treated in Urban India

Objective:

To study the outcome of childhood-onset drug-resistant epilepsy.

Methods:

Fifty-five patients with drug-resistant epilepsy, meeting inclusion criteria, were identified from the Pediatric Neurology Clinic database with seizure onset less than age 13 years and a minimum follow-up of 5 years. Seizure remission was defined as no more than 1 seizure/year. Kaplan-Meier analysis was used to calculate the annual probability of seizure remission. Chi-square/Kruskal-Wallis tests were used to detect differences in predictors between those with seizure remission, ≥75% improvement and <75% improvement based on caregiver reports.

Results:

Median follow-up was 11 years. Of 55, 22 (40%) were in seizure remission at last contact; 14 (25.4%) improved by ≥75%; 19 (34.5%) experienced <75% improvement. Annual remission probability was 3% in IQ ≥70 group and 2.48% in IQ <70 group (P = .126).

Conclusion:

This study shows patients with drug-resistant epilepsy treated in urban India can expect an overall remission rate of 2% per year starting from the third year of follow-up.

Role of Neuroinflammation in Evolution of Childhood Epilepsy

Until a decade ago, epilepsy research had focused mainly on alterations of neuronal activities and excitability. Such neurocentric emphasis has neglected the role of glia and involvement of inflammation in the pathogenesis of epilepsy. It is becoming clear that immune and inflammatory reactions do occur in the brain despite the brain's lack of conventional lymphatic drainage and graft acceptance and the presence of vascular brain barrier that tightly regulates infiltration of blood monocytes and lymphocytes. The critical roles of brain-resident immune mediators and of brain-infiltrating peripheral leukocytes are increasingly recognized. Inflammatory processes, including activation of microglia and astrocytes and production of proinflammatory cytokines and related molecules, occur in human epilepsy as well as in experimental models of epilepsy. Immune mechanism that underlies evolution of drug-resistant epilepsy and epileptic encephalopathy represents a new target and will aid in development of novel immunotherapeutic drugs and therapies against the key constituents in immune pathways.

Long-term outcomes of epilepsy surgery in 85 pediatric patients followed up for over 10 years: a retrospective survey

OBJECTIVE The aim of this study was to investigate the treatment outcomes and social engagement of patients who had undergone pediatric epilepsy surgery more than 10 years earlier. METHODS Between 1983 and 2005, 110 patients younger than 16 years underwent epilepsy surgery at the National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders. The authors sent a questionnaire to 103 patients who had undergone follow-up for more than 10 years after surgery; 85 patients (82.5%) responded. The survey contained 4 categories: seizure outcome, use of antiepileptic drugs, social participation, and general satisfaction with the surgical treatment (resection of the epileptic focus, including 4 hemispherectomies). The mean patient age at the time of surgery was 9.8 ± 4.2 (SD) years, and the mean duration of postoperative follow-up was 15.4 ± 5.0 years. Of the 85 patients, 79 (92.9%) presented with a lesional pathology, such as medial temporal sclerosis, developmental/neoplastic lesions, focal cortical dysplasia, and gliosis in a single lobe. RESULTS For 65 of the 85 responders (76.5%), the outcome was recorded as Engel Class I (including 15 [93.8%] of 16 patients with medial temporal sclerosis, 20 [80.0%] of 25 with developmental/neoplastic lesions, and 27 [73.0%] of 37 with focal cortical dysplasia). Of these, 29 (44.6%) were not taking antiepileptic drugs at the time of our survey, 29 (44.6%) held full-time jobs, and 33 of 59 patients (55.9%) eligible to drive had a driver's license. Among 73 patients who reported their degree of satisfaction, 58 (79.5%) were very satisfied with the treatment outcome. CONCLUSIONS The seizure outcome in patients who underwent resective surgery in childhood and underwent followup for more than 10 years was good. Of 85 respondents, 65 (76.5%) were classified in Engel Class I. The degree of social engagement was relatively high, and the satisfaction level with the treatment outcome was also high. From the perspective of seizure control and social adaptation, resective surgery yielded longitudinal benefits in children with intractable epilepsy, especially those with a lesional pathology in a single lobe.

Surgical Treatment of Epilepsy in Pediatric Patients

Surgery has become an accepted treatment modality for carefully selected adults with intractable focal epilepsy. More recently, increasing numbers of pediatric patients with intractable epilepsy are also being referred for surgical consideration. Key elements of surgical candidacy include medically intractable focal epilepsy, a localized epileptogenic zone, and a low risk for new postoperative neurologic deficits. The most common etiologies of the epilepsies in pediatric surgical candidates are malformation of cortical development and low grade tumor but some patients with childhood onset temporal lobe epilepsy due to hippocampal sclerosis also present for early surgery. Based on results from several recent pediatric surgical series, the chance for favorable seizure outcome after surgery is not adversely affected by young age, with seizure-free postoperative outcome reported for 60% to 65% of infants, 59% to 67% of children, and 69% of adolescents, compared to 64% reported in a large, predominantly adult series. Some subgroups of patients have higher percentages of seizure-free outcome, including those with hippocampal sclerosis or low grade tumor. In addition to seizures, developmental issues are also a major concern in children with intractable epilepsy. Few quantitative data are available, but some anecdotal experience suggests that surgical relief of catastrophic epilepsy may result in resumption of developmental progression after surgery, although the rate of development often remains abnormal. In one series, best developmental outcomes were seen in patients with earliest surgery and highest level of preoperative development. For each patient, the timing of surgery must be carefully considered, based on a full assessment of the relative risks and benefits, derived from a detailed presurgical evaluation.

Tailored disconnection based on presurgical evidence in catastrophic epilepsy: report of 2 cases

Catastrophic epilepsy in infants, often due to extensive cortical dysplasia, has devastating consequences with respect to brain development. Conventional lobar, multilobar, or hemispheric resection in these infants is challenging, carrying an increased operative risk compared with that in older children. Removing a larger tissue volume versus removing or disconnecting the epileptogenic region does not always guarantee better seizure outcome. The authors describe 2 infants with catastrophic epilepsy who benefited from individually tailored disconnections based on a hypothesized epileptogenic zone following intensive presurgical evaluation. Two infants with catastrophic epilepsy and epileptic spasms underwent leukotomies between 3 and 12 months of age. They were followed up postoperatively for 19-36 months. Both patients had 90%-100% seizure reduction and a significantly improved neurodevelopmental outcome without postoperative complication. Cortical malformation was seen in both patients. Modifications of established surgical disconnection techniques, tailored to each patient's specific epileptogenic zone, optimized seizure and neurodevelopmental outcomes while minimizing the risks associated with more extensive resections.

What is more harmful, seizures or epileptic EEG abnormalities? Is there any clinical data?

Cognitive impairment is a common and often devastating co-morbidity of childhood epilepsy. While the aetiology of the epilepsy is a critical determinant of cognitive outcome, there is considerable evidence from both rodent and human studies that indicate that seizures and interictal epileptiform abnormalities can contribute to cognitive impairment. A critical feature of childhood epilepsy is that the seizures and epileptiform activity occur in a brain with developing, plastic neuronal circuits. The consequences of seizures and interictal epileptiform activity in the developing brain differ from similar paroxysmal events occurring in the relatively fixed circuitry of the mature brain. In animals, it is possible to study interictal spikes independently from seizures, and it has been demonstrated that interictal spikes are as detrimental as seizures during brain development. In the clinic, distinguishing the differences between interictal spikes and seizures is more difficult, since both typically occur together. However, both seizures and interictal spikes result in transient cognitive impairment. Recurrent seizures, particularly when frequent, can lead to cognitive regression. While the clinical data linking interictal spikes to persistent cognitive impairment is limited, interictal spikes occurring during the formation and stabilization of neuronal circuits likely contribute to aberrant connectivity. There is insufficient clinical literature to indicate whether interictal spikes are more detrimental than seizures during brain development.

Computational modeling of seizure dynamics using coupled neuronal networks: factors shaping epileptiform activity

Epileptic seizure dynamics span multiple scales in space and time. Understanding seizure mechanisms requires identifying the relations between seizure components within and across these scales, together with the analysis of their dynamical repertoire. Mathematical models have been developed to reproduce seizure dynamics across scales ranging from the single neuron to the neural population. In this study, we develop a network model of spiking neurons and systematically investigate the conditions, under which the network displays the emergent dynamic behaviors known from the Epileptor, which is a well-investigated abstract model of epileptic neural activity. This approach allows us to study the biophysical parameters and variables leading to epileptiform discharges at cellular and network levels. Our network model is composed of two neuronal populations, characterized by fast excitatory bursting neurons and regular spiking inhibitory neurons, embedded in a common extracellular environment represented by a slow variable. By systematically analyzing the parameter landscape offered by the simulation framework, we reproduce typical sequences of neural activity observed during status epilepticus. We find that exogenous fluctuations from extracellular environment and electro-tonic couplings play a major role in the progression of the seizure, which supports previous studies and further validates our model. We also investigate the influence of chemical synaptic coupling in the generation of spontaneous seizure-like events. Our results argue towards a temporal shift of typical spike waves with fast discharges as synaptic strengths are varied. We demonstrate that spike waves, including interictal spikes, are generated primarily by inhibitory neurons, whereas fast discharges during the wave part are due to excitatory neurons. Simulated traces are compared with in vivo experimental data from rodents at different stages of the disorder. We draw the conclusion that slow variations of global excitability, due to exogenous fluctuations from extracellular environment, and gap junction communication push the system into paroxysmal regimes. We discuss potential mechanisms underlying such machinery and the relevance of our approach, supporting previous detailed modeling studies and reflecting on the limitations of our methodology.

Neurons communicate via different types of synapses on very fast time scales. The combination of hundred thousand of such interconnected cells within a fluctuating extracellular environment forms a complex network that gives rise to function and behavior via the formation of dynamical patterns of activity. In the context of epilepsy, the functional properties of the network at the source of a seizure are disrupted by a possibly large set of factors at the cellular and molecular levels. It is therefore needed to sacrifice some biological accuracy to model seizure dynamics in favor of macroscopic realizations. Here, we present a neuronal network model that convenes both neuronal and network representations with the goal to describe brain dynamics involved in the development of epilepsy. We compare our modeling results with animal in vivo recordings to validate our approach in the context of seizures. Such system-level methodology has significant bearing in understanding neuronal network dynamics that entangle multiple synaptic and extracellular modalities.

Seizure occurrence during pediatric short-term EEG

AIM

To identify the patients who are more likely to experience a seizure during short-term EEG recording.

METHODS

We retrospectively reviewed the EEG recordings and medical records of 294 patients, who were admitted to the Pediatric Departments in Assaf Harofeh Medical Center, and referred for a short-term EEG during a 5-years period following a seizure.

RESULTS

Fifteen (5.1%) patients had seizures during short-term EEG. The likelihood of seizure occurrence was increased by history of seizures (odds ratio 11.86, 95% confidence interval 2.54-55.37), abnormal neurological examination (odds ratio 3.33, 95% confidence interval 1.05-10.55), and the presence of interictal epileptiform discharges (odds ratio 10.07, 95% confidence interval 1.26-80.42). Treatment with antiepileptic drugs and mental retardation were significantly more common among patients with seizures.

CONCLUSIONS

Children with a higher likelihood of a seizure during short-term EEG can be identified using data mainly obtained by history and neurological examination.

Predictors of spontaneous transient seizure remission in patients of medically refractory epilepsy due to mesial temporal sclerosis (MTS)

PURPOSE

To analyze the predictors of spontaneous transient seizure remission for ≥1 year in patients with drug-resistant epilepsy (DRE) due to mesial temporal sclerosis (MTS).

METHODS

This analysis included 38 patients with DRE (M:F = 20:18, age: 31.7 ± 10.9 years) diagnosed with unilateral MTS (right:left = 16:22). Group I ('remission' group) comprised of patients with seizure remission (M:F = 10:8, age: 32.8 ± 12.3 years, mean seizure free period: 2.2 ± 1.1 years; median: 2.1 years). Group II ('non-remission' group) comprised of age and gender matched 20 patients (M:F = 10:10, age: 30.7 ± 9.7 years) with unilateral MTS who never had seizure remission and subsequently underwent epilepsy surgery. Groups I and II were compared to find the predictors associated with transient seizure remission.

RESULTS

The age at onset of seizures in group I was 13.2 ± 11.8 years and in group II was 12.0 ± 7.6 years. The duration of seizure was: group I - 19.7 ± 12.5 years and group II - 19.3 ± 7.7 years. Past history of seizure remissions (p < 0.001), frequent periods of remissions (p < 0.001), first remission within a year of onset of seizures (p = 0.04) and normal EEG (p = 0.04) were the important clinical predictors associated with seizure remission in this cohort. Fifteen patients in group I (83.3%) experienced remission following either change in AED (p ≤ 0.001) or increase in AED dosages (p < 0.001). There was no difference between the two groups regarding the type of semiology (partial vs. secondarily generalized) (p = 0.50), family history of seizures (p = 1.0), side of the lesion (p = 0.34), history of febrile seizures (p = 1.0) and the number of AEDs used (p = 0.53).

CONCLUSION

The present study unfolds, some of the clinically relevant predictors associated with transient seizure remission in patients with DRE and MTS. Future molecular and network studies are required to understand its mechanism.

Effectiveness of the ketogenic diet used to treat resistant childhood epilepsy in Scandinavia

BACKGROUND

This Scandinavian collaborative retrospective study of children treated with ketogenic diet (KD) highlights indications and effectiveness over two years follow-up.

METHODS

Five centres specialised in KD collected data retrospectively on 315 patients started on KD from 1999 to 2009. Twenty-five patients who stopped the diet within four weeks because of compliance-problems and minor side-effects were excluded. Seizure-type(s), seizure-frequency, anti-epileptic drugs and other treatments, mental retardation, autism-spectrum disorder and motor-dysfunction were identified and treatment-response was evaluated.

RESULTS

An intention-to-treat analysis was used. Responders (>50% seizure-frequency reduction) at 6, 12 and 24 months were 50%, 46% and 28% respectively, seizure-free were 16%, 13% and 10%. Still on the diet were 80%, 64% and 41% after 6, 12 and 24 months. No child had an increased seizure-frequency. The best seizure outcome was seen in the group with not-daily seizures at baseline (n = 22), where 45%, 41% and 32% became seizure-free at 6, 12 and 24 months A significant improvement in seizure-frequency was seen in atonic seizures at three months and secondary generalised seizures at three and six months. Side-effects were noted in 29 subjects; most could be treated and only two stopped due to hyperlipidaemia and two due to kidney-stones. In 167 patients treated with potassium-citrate, one developed kidney-stones, compared with six of 123 without potassium-citrate treatment (relative risk = 8.1).

CONCLUSIONS

As the first study of implementing KD in children in the Scandinavian countries, our survey of 290 children showed that KD is effective and well tolerated, even in such severe patients with therapy-resistant epilepsy, more than daily seizures and intellectual disability in the majority of patients. Long-term efficacy of KD was comparable or even better than reported in newer AEDs. Addition of potassium citrate reduced risk of kidney-stones. Our data indicate that the response might be predicted by seizure-frequency before initiation of the diet but not by age, seizure-type or aetiology.

Refractory epilepsy in children

Refractory epilepsy, estimated to affect 10-20% children with epilepsy, can have profound effect on the education, social and cognitive functioning and recreational activities of the child. The definitions are still evolving. A detailed clinical evaluation may reveal an accurate syndromic and etiological diagnosis. The recent advances in neuroimaging and electrophysiology have revolutionized the management of children with refractory epilepsy and supplement the clinical evaluation. Genetic and metabolic evaluation may be indicated in selected cases. The rational use of anti-epileptic drugs, epilepsy surgery and dietary therapies are the mainstay in the management. Various experimental treatment options and pharmacogenetics offer hope for future.

Epilepsy surgery in children: why, when and how?

Epilepsy surgery is safe and effective treatment in children who fail to respond to antiepileptic medications. After failure of two appropriate antiepileptic medications, chances that the child will become seizure free with more or different medications is <5%, and she should be diagnosed with "refractory epilepsy". A consideration for surgical candidacy should be given to all children who fulfill the definition of refractory epilepsy. In appropriately selected children, epilepsy surgery offers a high chance of seizure freedom without incurring any new post-operative neurological deficits. No age is bar to epilepsy surgery. Even infants can safely have epilepsy surgery if they are surgical candidates. For most children, who are surgical candidates, a good history and physical examination, video EEG evaluation, and a high quality brain MRI are sufficient to make surgical decision. These tools are increasingly available all over the world. Better education of families, Pediatricians, Pediatric Neurologists and community care-givers is necessary to salvage children early from mortality and morbidity of untreated, sometimes life long, epilepsy.

Polymorphism of ABCB1/MDR1 C3435T in children and adolescents with partial epilepsy is due to different criteria for drug resistance - preliminary results

Background

The diagnosis of “drug resistance” in epilepsy can be defined and interpreted in various ways. This may be due to discrepant definitions of drug resistance to pharmacotherapy.

The aim of our study was to investigate the relationship between C3435T polymorphism of the MDR1 gene and drug resistance in epilepsy with the consideration of 4 different criteria for qualification to groups sensitive and resistant to applied pharmacotherapy.

Material/Methods

Evaluation of C3435T polymorphism of MDR1/ABCB1 gene was conducted on a group of 82 white children and young adolescents up to 18 years old. While qualifying the patients to the group of sensitive or drug resistant, the following 4 definitions of drug resistance were applied: the ILAE’s, Appleton’s, Siddiqui’s, and Berg’s.

Results

A detailed analysis of genotypes of the MDR1 gene did not show any significant discrepancies between the groups of patients resistant and sensitive to antiepileptic drugs (AEDs) in 4 consecutive comparisons taking into consideration various criteria of sensitivity and resistance to pharmacotherapy.

Conclusions

The obtained results clearly confirm the lack of a connection between the occurrence of drug-resistant epilepsy and C435T polymorphism of the MDR1 gene irrespective of the definition of drug resistance applied to the patient.

What happens to children with epilepsy when they become adults? Some facts and opinions

BACKGROUND

The adult outcome after childhood onset epilepsy is a complex subject because seizure types and severity are diverse, comorbidities are common, and additional factors influence social outcome. We review selected data about seizure remission or persistence and social outcome in adulthood.

METHODS

Information came from published literature, especially population-based studies.

RESULTS

In general, approximately 50-60% of children with epilepsy eventually have complete seizure remission (i.e., seizure free and off antiepileptic drug treatment): with longer follow-up, the remission rate improves. Predicting remission, persistent or intractable epilepsy is often inaccurate for an individual patient. A tiny proportion of children with epilepsy die as the result of seizures or sudden unexpected death in epilepsy patients; however, an otherwise normal child has the same risk of death as the reference population. When uncontrolled epilepsy persists into adulthood, the rate of sudden unexpected death in epilepsy patients possibly increases. Reports about social outcome in adulthood are increasing. For those with intellectual disability, a lifetime of dependency is to be expected. For those with normal intelligence, adult life is often unsatisfactory with high rates of incomplete education, unemployment, poverty, social isolation, inadvertent pregnancy, and psychiatric disorders. Seizure remission does not ensure good adult social outcome.

CONCLUSIONS

Although seizure control in childhood is important, anticipating poor social outcome in adulthood may allow earlier interventions. A well-orchestrated transition from pediatric to adult health care may be beneficial for the 40-50% with persistent seizures and for the majority who are at risk for adult social difficulties.

Narrative processing in typically developing children and children with early unilateral brain injury: seeing gesture matters

Narrative skill in kindergarteners has been shown to be a reliable predictor of later reading comprehension and school achievement. However, we know little about how to scaffold children's narrative skill. Here we examine whether the quality of kindergarten children's narrative retellings depends on the kind of narrative elicitation they are given. We asked this question with respect to typically developing (TD) kindergarten children and children with pre- or perinatal unilateral brain injury (PL), a group that has been shown to have difficulty with narrative production. We compared children's skill in retelling stories originally presented to them in 4 different elicitation formats: (a) wordless cartoons, (b) stories told by a narrator through the auditory modality, (c) stories told by a narrator through the audiovisual modality without co-speech gestures, and (e) stories told by a narrator in the audiovisual modality with co-speech gestures. We found that children told better structured narratives in response to the audiovisual + gesture elicitation format than in response to the other 3 elicitation formats, consistent with findings that co-speech gestures can scaffold other aspects of language and memory. The audiovisual + gesture elicitation format was particularly beneficial for children who had the most difficulty telling a well-structured narrative, a group that included children with larger lesions associated with cerebrovascular infarcts.

Use of the ketogenic diet as a treatment for epilepsy refractory to drug treatment

The ketogenic diet is a high-fat, low-carbohydrate and low-protein diet used in the treatment of epilepsy that does not respond to antiepileptic drugs. The diet has been found to be very effective in treating intractable epilepsy in children. There is also some evidence that the diet is useful in treating drug-resistant epilepsy in infants, adolescents and adults. This paper traces the history and development of the ketogenic diet and reviews the clinical and animal research investigating its effects.

Epilepsy surgery in children with accompanying impairments

The aim of this study was to assess seizure outcome 2 years after epilepsy surgery in a consecutive series of paediatric patients, with special focus on children with learning disabilities and other neuroimpairments in addition to the epilepsy. Outcome 2 years after surgery was assessed in 110 of 125 children operated upon for drug resistant epilepsy in Gothenburg 1987-2006. More than half of the children had learning disabilities, 43% motor impairments and 30% a neuropsychiatric diagnosis. Fifty-six per cent of those with an IQ < 70 became seizure-free or had a >75% reduction in seizure frequency, and two thirds if the operation was a resection. The corresponding figure in those with more than 100 seizures per month was 15 out of 31, and another seven had a 50-75% reduction in seizure frequency. The message is that learning disability, motor impairment and psychiatric morbidity should not be contraindications for paediatric epilepsy surgery. More than half of the children with learning disabilities had a worthwhile seizure outcome, with even better results after resective surgery. Children with drug resistant epilepsy and additional severe neurological impairments should have the benefit of referral to a tertiary centre for evaluation for epilepsy surgery.

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.

Access to surgery for paediatric patients with medically refractory epilepsy: a systems analysis

PURPOSE

A systems analysis perspective was undertaken to evaluate access to surgery for children with medically refractory epilepsy (MRE) in Ontario, the largest province in Canada. The analysis focused on the assessment of referral patterns, healthcare utilization, time intervals and patient flow to determine surgical candidacy in children with MRE. The purpose of this systems analysis study was to identify rate limiting steps that may lead to delayed surgical candidacy decision and surgery.

METHODS

Prolonged video electroencephalography (vEEG) is the common entry point into the process for all potential epilepsy surgery candidates. Therefore, a single centre retrospective chart review of children and adolescents referred to the epilepsy monitoring unit (EMU) for vEEG monitoring at the primary referral centre for paediatric epilepsy surgery in the province. Basic demographic and referral data were abstracted for all screened cases. Included cases were: (1) age <19 years old at time of first EMU admission, (2) date of EMU admission between April 1, 2004 and March 31, 2006 and (3) referral for elective vEEG and/or overnight with vEEG greater than 8h duration. Data were collected on number of seizure conferences, surgical candidacy, surgical outcomes (seizure free and seizure reduction), resource utilization, and recorded time stamps for each event to estimate system delays.

RESULTS

During the two-year period, 463 patients were referred to the EMU of whom 349 received prolonged vEEG (>8h). Forty five percent (n=160) of patients came to seizure conference for discussion of their data, of whom 40% (64/160) were considered surgical candidates. Time from first seizure to EMU referral was approximately 4.6 years. Time from referral to admission and admission to first seizure conference were approximately 103 days and 71 days, respectively. From initial EMU referral to surgery ranged from 1.6 to 1.1 years depending on whether the patient required invasive monitoring with intracranial EEG. Overall, 95% of surgical patients had a reduction in seizure frequency, 74% were seizure free after one year post-surgery.

SIGNIFICANCE

Referral rates for surgical assessment are low relative to the estimated number of children living with MRE in Ontario, less than 2%. Hence, only a limited number of children with this disorder in the province of Ontario who could benefit from epilepsy surgery are being assessed for surgical candidacy. The majority of Ontario children with MRE are not being provided the potential opportunity to be seizure free and live without functional limitations following surgical intervention. These data document the critical need for health system redesign in Ontario, the goal of which should be to provide more consistent and just access to evidence-based medical and surgical care for those citizens of the province who suffer from epilepsy.

Cognitive outcome after epilepsy surgery in children

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

Predicting pharmacoresistance in pediatric epilepsy

Approximately 20% of children with epilepsy will be pharmacoresistant. The impact of intractable epilepsy extends far beyond just the seizures to result in intellectual disability, psychiatric comorbidity, physical injury, sudden unexpected death in epilepsy (SUDEP), and poor quality of life. Various predictors of pharmacoresistance have been identified; however, accurate prediction is still challenging. Population-based epidemiologic studies show that the majority of children who develop pharmacoresistance do so relatively early in the course of their epilepsy. However, approximately one third of children who initially appear pharmacoresistant in the first few years after epilepsy onset will ultimately achieve seizure freedom without surgery. The most significant predictor that early pharmacoresistance will not remit is the presence of a neuroimaging abnormality. Such children should be strongly considered for surgical evaluation.

Autism as early neurodevelopmental disorder: evidence for an sAPPα-mediated anabolic pathway

Autism is a neurodevelopmental disorder marked by social skills and communication deficits and interfering repetitive behavior. Intellectual disability often accompanies autism. In addition to behavioral deficits, autism is characterized by neuropathology and brain overgrowth. Increased intracranial volume often accompanies this brain growth. We have found that the Alzheimer's disease (AD) associated amyloid-β precursor protein (APP), especially its neuroprotective processing product, secreted APP α, is elevated in persons with autism. This has led to the "anabolic hypothesis" of autism etiology, in which neuronal overgrowth in the brain results in interneuronal misconnections that may underlie multiple autism symptoms. We review the contribution of research in brain volume and of APP to the anabolic hypothesis, and relate APP to other proteins and pathways that have already been directly associated with autism, such as fragile X mental retardation protein, Ras small GTPase/extracellular signal-regulated kinase, and phosphoinositide 3 kinase/protein kinase B/mammalian target of rapamycin. We also present additional evidence of magnetic resonance imaging intracranial measurements in favor of the anabolic hypothesis. Finally, since it appears that APP's involvement in autism is part of a multi-partner network, we extend this concept into the inherently interactive realm of epigenetics. We speculate that the underlying molecular abnormalities that influence APP's contribution to autism are epigenetic markers overlaid onto potentially vulnerable gene sequences due to environmental influence.

What predicts enduring intractability in children who appear medically intractable in the first 2 years after diagnosis?

PURPOSE

In a population-based retrospective cohort of children with newly diagnosed epilepsy, to determine (1) what proportion meet criteria for early medical intractability, and (2) predictors of enduring intractability.

METHODS

Children with newly diagnosed epilepsy between 1980 and 2009 while resident in Olmsted County, MN, and followed >36 months, were stratified into groups based on both early medical intractability ("apparent" medical intractability in the first 2 years) and enduring intractability (persisting intractability at final follow-up or having undergone surgery for intractable epilepsy), and variables predicting these outcomes were evaluated.

KEY FINDINGS

Three hundred eighty-one children were included, representing 81% of our cohort with newly diagnosed epilepsy. Seventy five (19.7%) had early medical intractability, and predictors of this outcome on multivariable analysis were neuroimaging abnormality (risk ratio, 2.70; p = 0.0004), abnormal neurologic examination at diagnosis (risk ratio, 1.87; p = 0.015), and mode of onset (association was significant for focal vs. generalized onset [risk ratio, 0.25; p < 0.0001] but not unknown vs. generalized onset [p = 0.065]). After a median follow-up of 11.7 years, 49% remained intractable, 8% had rare seizures (≤ every 6 months), and the remainder were seizure-free. The only factor predicting enduring intractability on multivariable analysis was neuroimaging abnormality (risk ratio, 7.0; p = 0.0006).

SIGNIFICANCE

Although a significant minority of children with early medical intractability ultimately achieved seizure control without surgery, those with an abnormal imaging study did poorly. For this subgroup, early surgical intervention is strongly advised to limit comorbidities of ongoing, intractable seizures. Conversely, a cautious approach is suggested for those with normal imaging, as most will remit with time.

Searching for new targets for treatment of pediatric epilepsy

The highest incidence of seizures in humans occurs during the first year of life. The high susceptibility to seizures in neonates and infants is paralleled by animal studies showing a high propensity to seizures during early life. The immature brain is highly susceptible to seizures because of an imbalance of excitation and inhibition. While the primary outcome determinant of early-life seizures is etiology, there is evidence that seizures which are frequent or prolonged can result in long-term adverse consequences, and there is a consensus that recurrent early-life seizures should be treated. Unfortunately, seizures in many neonates and children remain refractory to therapy. There is therefore a pressing need for new seizure drugs as well as antiepileptic targets in children. In this review, we focus on mechanisms of early-life seizures, such as hypoxia-ischemia, and novel molecular targets, including the hyperpolarization-activated cyclic nucleotide-gated channels.

Depression symptoms as a function of duration of intractable or controlled epilepsy

We examined if depression symptoms in patients with intractable (IE) or controlled epilepsy (CE) differ and how long after onset of epilepsy these effects would be most pronounced. The NDDI-E was administered to all outpatients (n=358) seen in a comprehensive epilepsy program clinic over a two-year period. Patients who met inclusion criteria (n=223) completed a total of 431 NDDI-E surveys over this time. Patients with a diagnosis of IE (n=72) or CE (n=151) were compared as a function of time since their epilepsy onset, segmented into 10-year epochs. Depression symptoms were higher in patients with IE compared to CE at 10-<20 years and did not differ at other time points. This study reveals differences in depression symptoms as a function of duration of epilepsy. Attending to the dynamic nature of depression symptoms in different epochs of epilepsy may be an important treatment target in patients with epilepsy.

Onset of intractability and its course over time: the Dutch study of epilepsy in childhood

PURPOSE

Intractability in epilepsy is difficult to define, and little is known about its onset, course, and duration. We investigated these aspects (as well as the occurrence of intractability) during long-term follow-up in patients with epilepsy, focusing on possible explanations for the variation in time of onset and duration of intractability.

METHODS

After diagnosis, 453 patients with childhood-onset epilepsy had a 5-year follow-up with regular visits and data collection. Ten years later they received a questionnaire with items concerning epilepsy, which was completed by 413 patients resulting in a mean follow-up of 15 years. Intractability during the first 5 years was compared with that in the last year of follow-up. Intractability was defined as having no 3-month remission during a 1-year period despite adequate medical treatment.

KEY FINDINGS

At least 12.1% of the cohort had a period of intractability during the 15-year follow-up, and 8.5% were intractable in the final year. Of the patients with idiopathic etiology 4.3% had a period of intractability versus 17.0% for those with cryptogenic, and 22.6% for those with remote symptomatic etiology (p < 0.001). Other risk factors at baseline were younger age at first seizure, generalized cryptogenic/symptomatic or localization-related symptomatic epilepsy, mental retardation, and febrile convulsions before enrollment. The cumulative risk of a period of intractability was 6.1% (95% confidence interval [CI] 3.7-8.5) at 2 years follow-up and 8.2% (95% CI 5.4-11.0) at 5 years. The mean time to onset of intractability during the first 5 years of follow-up was 1.6 (95% CI 1.3-2.0; median 1.0) years and the mean duration of intractability during these 5 years was 3.3 (95% CI 2.8-3.8; median 3.6) years. Fifteen patients were intractable only during the first 5 years of follow-up (group A), and 19 subjects were intractable both during the first 5 years and the last year of follow-up (group B). Compared with group A, group B had shorter remission and a longer time to intractability during the first 5 years and more were intractable in the fifth year of follow-up. Sixteen other patients had a late onset of intractability after 5 years of follow-up, sometimes after long periods of remission (group C). No significant differences in baseline characteristics were found among groups A, B, and C, but slightly more children in groups B and C became mentally retarded during the follow-up. In all groups, antiepileptic drugs were of little use in preventing and ending intractability.

SIGNIFICANCE

There is a large unpredictable variation in time of onset, course, and duration of intractability, with a higher chance of final intractability after a poor course during the first 5 years of follow-up. The natural course of epilepsy probably best explains the variable course of intractability. The effect of medication seems to be minor.

Early-life seizures produce lasting alterations in the structure and function of the prefrontal cortex

Early-life seizures (ELS) are associated with long-term behavioral disorders including autism and ADHD, suggesting that frontal lobe structures may be permanently affected. We tested whether ELS produce structural alterations in the prefrontal cortex (PFC) and impair PFC-mediated function using an operant task of behavioral flexibility in rats. Adult rats that had been exposed to 75 flurothyl seizures during postnatal days 1-10 showed decreased behavioral flexibility in the task compared to controls over multiple behavioral sessions, measured as a lever preference asymmetry (p<0.001) and a decreased efficiency of attaining food rewards (p<0.05). ELS rats also showed an increased thickness of the PFC (p<0.01), primarily attributed to layer V (p<0.01) with no differences in cell density. These structural changes correlated with lever preference behavioral impairments (p<0.05). This study demonstrates that the consequences of ELS extend to the PFC, which may help explain the high prevalence of comorbid behavioral disorders following ELS.

Ethical issues in surgical decision making concerning children with medically intractable epilepsy

The widespread inclusion of surgical strategies in the treatment of medically intractable epilepsy is largely justified by the medical and psychosocial burden of the illness. Performing these procedures in pediatric populations is associated with distinct challenges ranging from unique seizure etiologies to issues surrounding brain development and functional plasticity. As the trend toward more aggressive surgical intervention continues, the ethical foundation of current and emerging practices must be increasingly scrutinized. Here, we present the first article discussing ethical issues in the surgical management of medically intractable epilepsies in children. We discuss principles of informed consent, harm reduction, and justice in this vulnerable patient population. We also highlight the unique ethical challenge of surgical decision making concerning developmentally delayed children. The recognition of these issues is essential to providing patient-centered, responsible, and ethical care.

Surgical management of intractable childhood epilepsy: curative and palliative procedures

Epilepsy surgery is increasingly used to treat intractable childhood-onset epilepsy although it remains an underused treatment option. Advances in technology allowing more accurate identification of the epileptogenic zone along with a better understanding of the benefits of both curative and palliative epilepsy surgery have resulted in an increase of potential candidates. This review covers factors contributing to medical intractability and then details the evaluation of potential surgical candidates. We discuss pre-, peri-, and postoperative variables that lead to curative procedures and highlight the role of palliative epilepsy surgery in cases in which seizure freedom is unlikely.

Predictors of refractory epilepsy in north India: a case-control study

The study was done to identify the predictors of refractory epilepsy in the North Indian population attending a tertiary care centre. This case-control study from August 2006 to December 2008 enrolled 200 consecutive patients of intractable epilepsy and 200 age matched controls with well controlled epilepsy. The factors which were significant in univariate analysis were age of onset before fourteen years (OR 7.92), partial seizures (OR 6.27), presence of neurological deficits (OR 19.68), perinatal insult (OR 11.00), delayed milestones (OR 13.93), history of CNS infection (OR 7.45), febrile seizures (4.33), high initial seizure frequency of more than one per month (OR 14.26), non response to first Anti Epileptic Drug (AED) (OR 6.71) and abnormal brain imaging (OR 20.47). On multivariate analysis significant predictors were radiological evidence of structural cerebral abnormality (OR 20.47), non response to first AED (OR 19.21), delayed mile stones (OR 9.09), high initial seizure frequency of more than one per month (OR 6.71), partial seizure type (OR 6.27), febrile seizures (OR 5.66) and age of onset before fourteen years (OR 3.09). It is thus possible to identify a certain profile of patients with epilepsy who are likely to be refractory to medical therapy. These observations would be useful in selecting patients early for evaluation in Northern India where a high surgical treatment gap exists.

Remission and relapse in a drug-resistant epilepsy population followed prospectively

PURPOSE

We investigated the cumulative probability of seizure remission and relapse in an adult population with drug-resistant epilepsy and frequent seizures. In addition, we determined clinical predictors of remission and relapse in this population.

METHODS

IN 2003, we identified 246 patients at a single center with drug-resistant epilepsy defined as at least one seizure per month and failure of at least two antiepileptic drugs. These patients were followed prospectively (cohort design). We examined the cumulative probability of seizure remission and relapse in this population using Kaplan-Meier methodology. Clinical predictors of remission and relapse were also evaluated using Cox regression analysis.

KEY FINDINGS

The estimated cumulative probability of 12-month seizure remission was 34.6% at 7 years in the entire population and 33.4% when limited to those without surgery. The risk for relapse after a 12-month period of seizure remission was 71.2% at 5 years. Negative predictors of seizure remission included developmental delay, symptomatic generalized epilepsy syndrome, duration of intractability, and number of antiepileptic drugs failed. Localization-related epilepsy was the only negative predictor of relapse.

SIGNIFICANCE

Among patients with drug-resistant epilepsy, 5% per year enter seizure remission even with a follow-up of 6 years. However, a substantial proportion of these patients relapse after the first year following a remission. The large proportion of patients entering a significant remission gives these patients hope; however, caution should be advised when discussing the likelihood of future seizures.

Seizure remission in adults with long-standing intractable epilepsy: an extended follow-up

Recent studies have provided much needed data on the probability of seizure remission among adults with chronic intractable epilepsy treated medically. Here we provide an extended follow-up to our earlier study in order to provide a more comprehensive picture of long-term prognosis in this patient population during medical treatment. The prevalence cohort was followed for two outcomes-complete seizure remission for ≥ 12 months and subsequent seizure relapse among those attaining a seizure remission. The study outcomes were estimated using Kaplan-Meier analysis. We found that the probability of attaining a ≥ 12 months of complete seizure freedom to be approximately 3-4% per year through 8 years of follow-up. By year 5 since the start of seizure remission, the cumulative probability of seizure relapse was 81%, although only half of the patients with seizure relapse went on to experience their previous seizure frequency.

Attention networks in children with idiopathic generalized epilepsy

Attention deficit is one of the most frequent symptoms in children with idiopathic generalized epilepsy (IGE). However, it is unknown whether this is a global attention deficit or a deficit in a specific attention network. We used the attention network test (ANT) in children with IGE, who were not being treated with antiepileptic drugs (AEDs), to determine the efficiencies of three independent attention networks (alerting, orienting, and executive control). Children with IGE showed a significant deficit in their executive control network and in overall reaction time. However, they did not show any deficit in their alerting or orienting networks. These results suggest that IGE specifically affects the executive control network.

Course and outcome of childhood epilepsy: a 15-year follow-up of the Dutch Study of Epilepsy in Childhood

PURPOSE

To study the course and outcome of childhood-onset epilepsy during 15-year follow-up (FU).

METHODS

We extended FU in 413 of 494 children with new-onset epilepsy recruited in a previously described prospective hospital-based study by questionnaire.

RESULTS

Mean FU was 14.8 years (range 11.6-17.5 years). Five-year terminal remission (TR) was reached by 71% of the cohort. Course during FU was favorable in 50%, improving in 29%, and poor or deteriorating in 16%. Mean duration of seizure activity was 6.0 years (range 0-21.5 years), strongly depending on etiology and epilepsy type. Duration was <1 year in 25% of the cohort and exceeded 12 years in another 25%. Antiepileptic drugs (AEDs) were used by 86% during a mean of 7.4 years: one-third had their last seizure within 1 year of treatment, and one-third continued treatment at the end, although some had a 5-year TR. At last contact, 9% of the cohort was intractable. In multivariate analysis, predictors were nonidiopathic etiology, febrile seizures, no 3-month remission, and early intractability. Eighteen patients died; 17 had remote symptomatic etiology. Standardized mortality ratio for remote symptomatic etiology was 31.6 [95% confidence interval (CI) 18.4-50.6], versus 0.8 [95% CI 0.02-4.2] for idiopathic/cryptogenic etiology.

DISCUSSION

In most children with newly diagnosed epilepsy, the long-term prognosis of epilepsy is favorable, and in particular, patients with idiopathic etiology will eventually reach remission. In contrast, epilepsy remains active in approximately 30% and becomes intractable in approximately 10%. AEDs probably do not influence epilepsy course; they merely suppress seizures. Mortality is significantly higher only in those with remote symptomatic etiology.