Seizure Syndrome Research Articles

Commentary: ILAE Definition of Epilepsy.

Jessica Solodar is a writer focused on photic seizures triggered by electronic media. Although more than once we were told, “Good news–it's not epilepsy,” we didn't see it that way. It meant that because my daughter's case didn't meet strict diagnostic criteria, we'd be sent on our way without any diagnosis of epilepsy or plans for follow-up. Her seizures are evoked by environmental stimuli. Did that mean they qualify as unprovoked events? Although reflex epilepsy was already known to be a type of epilepsy, the previous diagnostic criteria allowed uncertainty among clinicians as to whether reflex epilepsy could be diagnosed in someone with no other seizure types. Clinicians were more concerned about the risks of overdiagnosis than about the ramifications for patients of underdiagnosis. It is therefore a most welcome step by the International League Against Epilepsy (ILAE) to broaden and refine the operational definition of epilepsy to make it more relevant and responsive to clinical care. The manner in which the authors present their reasoning demonstrates both flexible thinking and respect for the lives that may be affected by these changes. The new clinical definition addresses the need to consider more of the patient's circumstances, and it encourages a more nuanced analysis of the patient's history and seizure syndrome. By adapting the legalistic diagnostic criteria used in research, the authors of this practical definition have produced common sense–infused guidelines for clinicians. In addition, they have anticipated economic, psychological, and social challenges that the redefinition may introduce for patients. The task force has carefully considered the perspective of patients and families while also respecting and encouraging the independent judgment of clinicians. Although epilepsy should be a clinical diagnosis, in the absence of a practical clinical definition, some clinicians may not have felt free to interpret and temper the classic diagnostic criteria to make allowances for the particulars of a given case. When daily realities do not precisely fit the conceptual criteria, conceptual definitions can feel arbitrary, not terribly useful, and even alienating, because patients feel their own experiences and perspectives devalued. Of the specific changes in the new definition, the most significant for my family is the clarification that reflex epilepsy “counts” as a bona fide expression of the disease. The ILAE task force quite correctly describes patients with only this type of seizure as disenfranchised by prior definitions. In our experience, approaching specialists about my daughter's repeated reflex seizures typically led to the presenting complaint being set aside until unprovoked seizures could be confirmed (which in her case was not so straightforward). The new clinical definition should help remove a longstanding bias whereby reflex seizures are considered a medical curiosity1 and a freakish rarity that deserve little serious attention. Despite a 2005 consensus report2 identifying photic seizures as a public health risk, the marginalizing of photosensitive epilepsy among epilepsy specialists and very low awareness in other clinical fields persist, thereby delaying diagnosis. Moreover, ubiquitous audiovisual technologies in daily life are ever more liable to activate symptoms in those with latent photosensitivity; according to most researchers studying photic seizures, that population segment is likely larger than previous estimates. The ILAE's operational clinical definition should now bring wider attention to this seizure type, and encourage neurologists and their clinical colleagues in all areas of medicine to be mindful regarding photic seizures, even in individuals with no seizure history. The author has no conflicts of interest to disclose. I confirm that I have read the Journal's position on issues involved in ethical publication and affirm that this report is consistent with those guidelines.

Anti-N-Methyl-D-Aspartate (Anti-NMDA) Receptor Antibody Encephalitis in a Male Adolescent With a Large Mediastinal Teratoma

We present a case of a 16-year-old boy with Klinefelter syndrome who presented with a syndrome of impaired alertness, orofacial dyskinesias, choreiform movements, epileptic seizures, and autonomic instability, pointing to a diagnosis of anti-N-methyl-Daspartate (anti-NMDA) receptor antibody encephalitis.

Post-transfusion Hypertension and Seizure in Congenital Hemolytic anemia: A Case Report and Literature Review

A rare syndrome of hypertension, seizures and intracranial bleed has been reported among patients with congenital hemolytic anemia who underwent multiple blood transfusions. We report this syndrome in a 12-year-old Malay girl with hemoglobin E-beta-thalassemia, who underwent intensive transfusion and subsequently had headache, visual loss, severe hypertension and seizures. A comprehensive literature review revealed 30 patients with this syndrome, of whom 15 had intracranial bleed and 12 among these 15 died. A less-intensive transfusion regimen among patients with chronic hemolytic anemia and prompt detection and management of hypertension may prevent this potentially fatal syndrome.

The supposed tumor suppressor gene WWOX is mutated in an early lethal microcephaly syndrome with epilepsy, growth retardation and retinal degeneration

BackgroundWWOX, encoding WW domain-containing oxidoreductase, spans FRA16D, the second most common chromosomal fragile site frequently altered in cancers. It is therefore considered a tumor suppressor gene, but its direct implication in cancerogenesis remains controversial.Methods and resultsBy whole-exome sequencing, we identified a homozygous WWOX nonsense mutation, p.Arg54*, in a girl from a consanguineous family with a severe syndrome of growth retardation, microcephaly, epileptic seizures, retinopathy and early death, a phenotype highly similar to the abormalities reported in lde/lde rats with a spontaneous functional null mutation of Wwox. As in rats, no tumors were observed in the patient or heterozygous mutation carriers.ConclusionsOur finding, a homozygous loss-of-function germline mutation in WWOX in a patient with a lethal autosomal recessive syndrome, supports an alternative role of WWOX and indicates its importance for human viability.

Isolated Chorea Associated with LGI1 Antibody.

BackgroundLeucine-rich glioma inactivated 1 (LGI1) antibody produces a syndrome of limbic encephalitis, hyponatremia, and facio-brachial dystonic seizures that is non-paraneoplastic and responsive to corticosteroids. Parkinsonism, tremor, and generalized chorea are rare manifestations of LGI1, but, when present, commonly accompany other signs of limbic encephalitis.Case ReportWe present a case of LGI1-related isolated chorea in a 53-year-old Japanese male. His chorea responded to high-dose steroids, suggesting a potential role for this synaptic antibody in triggering chorea.DiscussionThis case highlights a new treatable etiology of chorea.

Isolated Chorea Associated with LGI1 Antibody

<strong>Background:</strong> Leucine-rich glioma inactivated 1 (LGI1) antibody produces a syndrome of limbic encephalitis, hyponatremia, and facio-brachial dystonic seizures that is non-paraneoplastic and responsive to corticosteroids. Parkinsonism, tremor, and generalized chorea are rare manifestations of LGI1, but, when present, commonly accompany other signs of limbic encephalitis. <strong>Case Report:</strong> We present a case of LGI1-related isolated chorea in a 53-year-old Japanese male. His chorea responded to high-dose steroids, suggesting a potential role for this synaptic antibody in triggering chorea. <strong>Discussion:</strong> This case highlights a new treatable etiology of chorea.

Sodium Channels, Inherited Epilepsy, and Antiepileptic Drugs

Voltage-gated sodium channels initiate action potentials in brain neurons, mutations in sodium channels cause inherited forms of epilepsy, and sodium channel blockers-along with other classes of drugs-are used in therapy of epilepsy. A mammalian voltage-gated sodium channel is a complex containing a large, pore-forming α subunit and one or two smaller β subunits. Extensive structure-function studies have revealed many aspects of the molecular basis for sodium channel structure, and X-ray crystallography of ancestral bacterial sodium channels has given insight into their three-dimensional structure. Mutations in sodium channel α and β subunits are responsible for genetic epilepsy syndromes with a wide range of severity, including generalized epilepsy with febrile seizures plus (GEFS+), Dravet syndrome, and benign familial neonatal-infantile seizures. These seizure syndromes are treated with antiepileptic drugs that offer differing degrees of success. The recent advances in understanding of disease mechanisms and sodium channel structure promise to yield improved therapeutic approaches.

What are the arguments for and against rational therapy for epilepsy?

Although more than a dozen new anti-seizure drugs (ASDs) have entered the market since 1993, a substantial proportion of patients (~30 %) remain refractory to current treatments. Thus, a concerted effort to identify and develop new therapies that will help these patients continues. Until this effort succeeds, it is reasonable to re-assess the use of currently available therapies and to consider how these therapies might be utilized in a more efficacious manner. This applies to the selection of monotherapies in newly-diagnosed epilepsy, but perhaps, more importantly, to the choice of combination treatments in otherwise drug-refractory epilepsy. Rational polytherapy is a concept that is predicated on the combination of drugs with complementary mechanisms of action (MoAs) that work synergistically to maximize efficacy and minimize the potential for adverse events. Furthermore, rational polytherapy requires a detailed understanding of the MoA subclasses amongst available ASDs and an appreciation of the empirical evidence that supports the use of specific combinations. The majority of ASDs can be loosely categorized into those that target neurotransmission and network hyperexcitability, modulate intrinsic neuronal properties through ion channels, or possess broad-spectrum efficacy as a result of multiple mechanisms. Within each of these categories, there are discrete pharmacological profiles that differentiate individual ASDs. This chapter will consider how knowledge of MoA can help guide therapy in a rational manner, both in the selection of monotherapies for specific seizure types and syndromes, but also in the choice of drug combinations for patients whose epilepsy is not optimally controlled with a single ASD.

The genetic basis of DOORS syndrome: an exome-sequencing study

SummaryBackgroundDeafness, onychodystrophy, osteodystrophy, mental retardation, and seizures (DOORS) syndrome is a rare autosomal recessive disorder of unknown cause. We aimed to identify the genetic basis of this syndrome by sequencing most coding exons in affected individuals.MethodsThrough a search of available case studies and communication with collaborators, we identified families that included at least one individual with at least three of the five main features of the DOORS syndrome: deafness, onychodystrophy, osteodystrophy, intellectual disability, and seizures. Participants were recruited from 26 centres in 17 countries. Families described in this study were enrolled between Dec 1, 2010, and March 1, 2013. Collaborating physicians enrolling participants obtained clinical information and DNA samples from the affected child and both parents if possible. We did whole-exome sequencing in affected individuals as they were enrolled, until we identified a candidate gene, and Sanger sequencing to confirm mutations. We did expression studies in human fibroblasts from one individual by real-time PCR and western blot analysis, and in mouse tissues by immunohistochemistry and real-time PCR.Findings26 families were included in the study. We did exome sequencing in the first 17 enrolled families; we screened for TBC1D24 by Sanger sequencing in subsequent families. We identified TBC1D24 mutations in 11 individuals from nine families (by exome sequencing in seven families, and Sanger sequencing in two families). 18 families had individuals with all five main features of DOORS syndrome, and TBC1D24 mutations were identified in half of these families. The seizure types in individuals with TBC1D24 mutations included generalised tonic-clonic, complex partial, focal clonic, and infantile spasms. Of the 18 individuals with DOORS syndrome from 17 families without TBC1D24 mutations, eight did not have seizures and three did not have deafness. In expression studies, some mutations abrogated TBC1D24 mRNA stability. We also detected Tbc1d24 expression in mouse phalangeal chondrocytes and calvaria, which suggests a role of TBC1D24 in skeletogenesis.InterpretationOur findings suggest that mutations in TBC1D24 seem to be an important cause of DOORS syndrome and can cause diverse phenotypes. Thus, individuals with DOORS syndrome without deafness and seizures but with the other features should still be screened for TBC1D24 mutations. More information is needed to understand the cellular roles of TBC1D24 and identify the genes responsible for DOORS phenotypes in individuals who do not have a mutation in TBC1D24.FundingUS National Institutes of Health, the CIHR (Canada), the NIHR (UK), the Wellcome Trust, the Henry Smith Charity, and Action Medical Research.

Progress of the syndrome of malignant migrating partial seizures in infancy

The syndrome of malignant migrating partial seizures in infancy (MMPSI) is one of the most severe epileptic encephalopathies of infancy onset.It has been firstly reported by Coppola in 1995.There have been approximately 80 cases reported worldwide by now,but there is no case reported in our country.The etiology for MMPSI is still unknown,the diagnosis is difficult,and conventional antiepileptic drugs have little efficacy.This paper reviews the possible causes,clinical characteristics,diagnosis and treatment of MMPSI. Key words: Epilepsy; Malignant migrating partial seizures in infancy; Epileptic encephalopathy; Electroencephalogram

Genetics of Benign Familial Infantile Epilepsies

Investigators at Instituto G Gaslini, Genova, Italy and multiple other centers in Italy studied the genetics of benign familial epilepsies of the first year of life and assessed the extent of the genetic overlap between neonatal and infantile seizure syndromes.

Genetics of febrile seizure subtypes and syndromes: A twin study

Febrile seizures (FS) are the most common seizure syndrome. A strong genetic component has been well established through family and twin studies; however, such studies have not examined the genetics of different FS types (simple, complex, febrile status epilepticus) and sub-syndromes (true FS, febrile seizures plus (FS+), 'FS with later epilepsy'). Here we used a community-based twin sample to analyze genetic factors within different FS subtypes and FS syndromes. Twin pairs were ascertained from the twin database of the Epilepsy Research Centre. A retrospective chart review was conducted and follow-up attempted for all subjects. Casewise concordance values were calculated for the different subgroups and intra-pair variation was analyzed. One hundred and seventy-nine twin pairs with FS were identified. Overall casewise concordance for FS in monozygotic (MZ) twins (0.62) was greater than in dizygotic (DZ) twins (0.16, p<0.0001). A greater concordance amongst MZ pairs than DZ twin pairs was also observed for all FS subtypes and FS sub-syndromes, particularly in twins with FS+. Within concordant MZ pairs, we did not observe the co-occurrence of FS and FS+. These results suggest a strong genetic contribution to different FS subtypes and sub-syndromes. They also support the existence of distinct genetic factors for different FS subtypes and sub-syndromes, especially FS+. This information is important for the strategic planning of next generation sequencing studies of febrile seizures.

Introduction

Based on a 2010 systematic review and meta-analysis, Beyenburg et al. 1 recently concluded that modern antiepileptic drugs (AEDs) have little impact on patients with refractory epilepsy, lamenting the lack of progress in the development of novel AEDs. Such articles have highlighted the importance of the continued quest for effective, novel therapies to help patients with this condition. This supplement provides an overview of the development of perampanel, the first non-competitive AMPA-type glutamate receptor antagonist to be developed as an adjunctive treatment for refractory partial-onset seizures. After years of development, this AED has now been approved by the European Medicines Agency (EMA) and the Food and Drug Administration (FDA). Perampanel has completed clinical evaluation in three pivotal, randomized, double-blind, placebo-controlled Phase III registration studies in patients experiencing partial-onset seizures despite treatment with up to three AEDs 2-4. In these studies, adjunctive perampanel provided significant improvements in seizure reduction. In addition, perampanel was associated with a favorable adverse event profile, with few cognitive or psychiatric side effects: a vital attribute in this vulnerable population. Previously, most AEDs have been discovered through serendipity, screening large numbers of compounds, or the further development of existing AEDs. Perampanel, however, is one of the few to be developed based upon a specific hypothesis of seizure inhibition. This development program will be reviewed by Andrew Satlin and colleagues in the first article in this supplement 5. In the second article, Michael Rogawski 6 provides an in-depth account of the role of AMPA receptors in seizures and epileptogenesis, while in the third article, Michael Rogawski and Takahisa Hanada 7 will go on to review the exciting possibilities of AMPA receptor antagonism and how perampanel utilizes this mechanism to inhibit seizure occurrence. As perampanel is now approved for use in Europe and the USA, it is important that clinicians have an understanding of how this drug can be used to treat patients in a real-life clinical setting. With this in mind, the fourth article in this supplement, by Frank Kerling and Burkhard Kasper 8, will provide an overview of efficacy data from the published Phase II and Phase III clinical trials. Alongside this, Jose Serratosa, Vicente Villanueva, Frank Kerling and Burkhard Kasper 9 will provide an overview of Phase II and Phase III safety data in the fifth article. Severe seizures are particularly difficult to control, and the more AEDs a patient has tried previously, the less likely they are to respond to the next AED 10. Therefore, in the sixth and final article in this supplement, David Ko and Eugene Ramsay 11 will discuss the efficacy of perampanel for the treatment of severe seizures in refractory patients already receiving one or more concomitant AEDs. As perampanel is now approved for use in Europe and the USA, we hope that the information covered in this supplement will support the reader in treating eligible and appropriate patients with this third-generation AED. However, it is important to recognize that the full potential of perampanel is not yet known and many challenges still remain. For example, ‘How effective will perampanel be in monotherapy?’ and ‘Will patients with generalized seizure types also benefit from treatment (as indicated in animal models) 12?’ Only further rigorous studies will be able to answer the question of whether perampanel is a broad spectrum AED for patients with varied seizure types and syndromes or not. The future is indeed exciting. David Squillacote, MD, of Eisai Inc. assisted in the preparation of the article by providing up-to-date data access and editorial support. Editorial support was provided by Hannah FitzGibbon, PhD, of Complete Medical Communications and was funded by Eisai Inc. E. Ben-Menachem is currently an investigator for Eisai and UCB Pharma and is a consultant for Biocontrol, Eisai, Janssen-Cilag, Lundbeck, and UCB Pharma. She has received a research grant from Västra Götelands Region and is chief editor of Acta Neurologica Scandinavica.

Limitations of Current GABA Agonists in Neonatal Seizures: Toward GABA Modulation Via the Targeting of Neuronal Cl− Transport

Neonatal intensive care has advanced rapidly in the last 40 years, with dramatic decreases in mortality and morbidity; however, for neonatal seizures, neither therapies nor outcomes have changed significantly. Basic and clinical studies indicate that seizures in neonates have long-term neurodevelopmental and psychiatric consequences, highlighting the need for novel pharmacotherapeutics. First-line treatments targeting GABAA receptors, like barbiturates and benzodiazepines, are limited in their efficacy and carry significant risks to the developing brain. Here, we review the use of current GABA agonist therapies for neonatal seizures and suggest other treatment strategies given recent developments in the understanding of disease pathogenesis. One promising avenue is the indirect manipulation of the GABAergic system, via the modulation of neuronal Cl− gradients, by targeting the cation-Cl− cotransporters (NKCC1 and KCC2) or their regulatory signaling molecules. This strategy might yield a novel class of more efficacious anti-epileptics with fewer side effects by specifically addressing disease pathophysiology. Moreover, this strategy may have ramifications for other adult seizure syndromes in which GABA receptor-mediated depolarizations play a pathogenic role, such as temporal lobe epilepsy.

Benign occipital lobe seizures: Natural progression and atypical evolution

Benign occipital seizure syndromes are benign childhood epilepsy syndromes and are mainly of two types, Panayiotopoulos syndrome, an autonomic epilepsy and idiopathic childhood occipital epilepsy of Gastaut (ICOE-G) including the idiopathic photosensitive occipital lobe epilepsy. Although both these types are categorized as occipital seizures, they are distinct in presentation and management. They can also be tricky to diagnose as visual symptoms may not always be the presenting feature and it is also not very easy to elicit visual hallucinations during history taking. These seizures have a good response to treatment; however, there could be atypical evolution and refractoriness to treatment especially with ICOE-G. We describe three children who presented with visual and non-visual symptoms and the electroencephalography (EEG) in all the three cases showed occipital paroxysms. We have emphasized the clues in the clinical history and EEG leading to the diagnosis of these distinct epilepsy syndromes. We have also discussed the natural course of these epilepsy syndromes with some atypical evolution, which clinicians need to be aware of during treatment of these children.

Progressive cerebellar atrophy and polyneuropathy: expanding the spectrum of PNKP mutations

We present a neurodegenerative disorder starting in early childhood of two brothers consisting of severe progressive polyneuropathy, severe progressive cerebellar atrophy, microcephaly, mild epilepsy, and intellectual disability. The cause of this rare syndrome was found to be a homozygous mutation (c.1250_1266dup, resulting in a frameshift p.Thr424GlyfsX48) in PNKP, identified by applying homozygosity mapping and whole-genome sequencing. Mutations in PNKP have previously been associated with a syndrome of microcephaly, seizures and developmental delay (MIM 613402), but not with a neurodegenerative disorder. PNKP is a dual-function enzyme with a key role in different pathways of DNA damage repair. DNA repair disorders can result in accelerated cell death, leading to underdevelopment and neurodegeneration. In skin fibroblasts from both affected individuals, we show increased susceptibility to apoptosis under stress conditions and reduced PNKP expression. PNKP is known to interact with DNA repair proteins involved in the onset of polyneuropathy and cerebellar degeneration; therefore, our findings explain this novel phenotype.

Neonatal Hypoxia and Seizures

1. Maria Gillam-Krakauer, MD* 2. Brian S. Carter, MD† 1. *Assistant Professor of Pediatrics, Division of Neonatology, Vanderbilt University Medical Center, Nashville, TN. 2. †Professor of Pediatrics, Section of Neonatology, Children's Mercy Hospital, Kansas City, MO. * Abbreviations: AED: : antiepileptic drug AMPA: : α-amino-3-hydroxyl-5-methyl-4-isoxazolepropionic acid ATP: : adenosine triphosphate CSF: : cerebrospinal fluid HIE: : hypoxic-ischemic encephalopathy MOCO: : molybdenum cofactor NMDA: : N -methyl-d-aspartic acid With 1 to 3 in 1,000 term neonates experiencing seizures, pediatricians need to know how to determine the seizure cause and manage appropriately, using brain imaging and treatments such as therapeutic hypothermia, xenon, and other pharmacologic therapies, in order to minimize long-term sequelae and leverage the infant brain's tremendous capacity for repair in the first 2 years after birth. After completing this article, readers should be able to: 1. Understand the pathophysiology of neonatal seizures. 2. Know the many disorders associated with seizures in the newborn. 3. Be aware of the characteristics of different neonatal seizure syndromes. 4. Know how to evaluate a newborn who is having seizures. 5. Be aware of the treatments for neonatal seizures. 6. Understand the characteristics and management of hypoxic-ischemic encephalopathy. Seizures occur during the newborn period at an incidence of ∼1 to 3 per 1,000 infants born at term. (1)(2)(3) Numerous systemic and neurologic conditions can manifest as seizures. Cerebral hypoxia-ischemia, defined as partial lack of oxygen resulting in reduction of blood flow to the brain, is the most frequent cause of seizures in the newborn period. It is important to determine the cause of neonatal seizures and institute the appropriate therapy to minimize the long-term sequelae of both the underlying condition and the seizure. Seizures are paroxysmal alterations in neurologic function caused by excessive synchronous depolarization of neurons within the central nervous system. Regardless of the underlying pathology manifesting as a seizure, all seizures are due to a shift in cell energy. This shift can result from failure of the adenosine triphosphate (ATP)–dependent sodium-potassium (Na+-K+) pump, an imbalance of inhibitory and excitatory neurotransmitters, and both excessive …

Ascending tonic‐clonic seizure syndrome in a dog following inadvertent intrathecal use of ionic contrast agent

To describe the successful management of ascending tonic-clonic seizure syndrome in a dog after inadvertent intrathecal administration of ionic contrast material. A 7-year-old, 5.9 kg, male castrated Miniature Pinscher inadvertently received intrathecal ionic contrast material during a myelogram to investigate cervical pain. Ascending tonic-clonic muscle spasms quickly progressed to generalized seizure activity that was resistant to anticonvulsant medications. The dog developed complete respiratory arrest, which necessitated mechanical ventilatory support for 26 hours. Pneumonia developed and was treated successfully. After resolution of seizure activity and resumption of voluntary respiration, the dog remained tetraparetic for 16 days and was not able to walk on his own for 20 days post contrast injection. Despite a prolonged recovery, the patient survived and recovered normal neurologic function. Intrathecal administration of ionic contrast material resulting in ascending tonic-clonic seizure syndrome is rarely reported in the human and veterinary literature. No previous veterinary report has described successful treatment after prolonged respiratory arrest. In previous veterinary reports, patients recovered complete neurologic function within hours to days in contrast to this report in which the patient was tetraparetic for 16 days. This report demonstrates complete recovery from intrathecal ionic contrast administration is possible despite a high dose of contrast and a prolonged recovery.

IS INTERICTAL EEG CORRELATED WITH THE SEIZURE TYPE IN IDIOPATHIC (GENETIC) GENERALIZED EPILEPSIES

Objectiveinvestigated the correlation between different interictal EEG abnormalities observed in patients with idiopathic (genetic) generalized epilepsies (IGEs) and their seizure types. Material & Methods In this cross-sectional study, all patients with the diagnosis of IGE, were recruited in the outpatient epilepsy clinic at Shiraz University of Medical Sciences, Iran, from 2008 through 2010. Demographic variables and relevant clinical and EEG variables were summarized descriptively. Statistical analyses were performed using independent samples T-test, Chi square and Fisher’s Exact tests to determine potentially significant differences. Resultsthirty-six patients were diagnosed ashaving IGE. Interictal EEG findings in patients with generalized tonic-clonic seizure (GTCS) compared to patients without GTCS were not different. Abnormal EEG findings in patients with myoclonic seizures compared to patients without these were not different either. However, normal EEGs were more frequently observed in patients with history of myoclonic seizures (P = 0.0001). EEG findings in patients with absences compared to patients without absences were not different. ConclusionEEG cannot differentiate the seizure types and therefore different syndromes of IGEs. Polyspikes, 3-Hz generalized spike-wave (GSW) complexes and 3.5-6 Hz GSW complexes, alone or in combinations, could be observed in various seizure types and syndromes of IGE. The key element in making the correct diagnosis is a detailed clinical history.

The utility of prolonged outpatient ambulatory EEG

PurposeILAE guidelines recommend the use of prolonged EEG where the diagnosis of epilepsy or the classification of the seizure syndrome is proving difficult. Due to its limited provision, video EEG monitoring is unavailable to many patients under investigation1. The aim of this study was to examine the utility of the alternate investigation of outpatient ambulatory EEG. MethodsIn this retrospective study we analysed 324 consecutive prolonged outpatient ambulatory EEGs lasting 72–96h (4–5 days), without medication withdrawal. EEG data and the clinical record were reviewed to investigate the utility of the investigation. ResultsOf 324 studies: 219 (68%) studies gave positive data, 116 (36%) showed interictal epileptiform discharges (IEDs), 167 (52%) had events. 105 (32%) studies were normal. Overall 51% of studies changed management of which 22% of studies changed the diagnosis and 29% of studies refined the diagnosis by classifying the epilepsy into focal or generalised. ConclusionThe present study confirms the diagnostic utility of outpatient ambulatory EEG in the diagnosis of paroxysmal events.