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Background: Spatiotemporal analysis of electroencephalography is commonly used for classification of events since it allows capturing dependencies across channels. The significant increase of feature vector dimensionality however introduce noise and thus it does not allow the classification models to be trained using a limited number of samples usually available in clinical studies., New Method: Thus, we investigate the classification of epileptic and non-epileptic events based on temporal and spectral analysis through the application of three different fusion schemes for the combination of information across channels. We compare the commonly used early-integration (EI) scheme - in which features are fused from all channels prior to classification - with two late-integration (LI) schemes performing per channel classification when: (i) the temporal context varies significantly across channels, thus local spatial training models are required, and (ii) the spatial variations are negligible in comparison to the inter-subject variation, thus only the temporal variation is modeled using a single global spatial training model. Furthermore, we perform dimensionality reduction either by feature selection or by principal component analysis., Results: The framework is applied on events that manifest across most channels, as generalized epileptic seizures, psychogenic non-epileptic seizures and vasovagal syncope. The three classification architectures were evaluated on EEG epochs from 11 subjects., Comparison With Existing Methods: Although direct comparison with other studies is difficult due to the different characteristics of each dataset, the achieved recognition accuracy of the LI fusion schemes outperforms the performance reported in the literature., Conclusions: The best scheme was the LI with global model which achieved 97% accuracy., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Epilepsy is one of the most common serious neurologic conditions. It is characterized by the tendency to have recurrent seizures, which arise against a backdrop of apparently normal brain activity. At present, clinical diagnosis relies on the following: (1) case history, which can be unreliable; (2) observation of transient abnormal activity during electroencephalography (EEG), which may not be present during clinical evaluation; and (3) if diagnostic uncertainty occurs, undertaking prolonged monitoring in an attempt to observe EEG abnormalities, which is costly. Herein, we describe the discovery and validation of an epilepsy biomarker based on computational analysis of a short segment of resting-state (interictal) EEG. Our method utilizes a computer model of dynamic networks, where the network is inferred from the extent of synchrony between EEG channels (functional networks) and the normalized power spectrum of the clinical data. We optimize model parameters using a leave-one-out classification on a dataset comprising 30 people with idiopathic generalized epilepsy (IGE) and 38 normal controls. Applying this scheme to all 68 subjects we find 100% specificity at 56.7% sensitivity, and 100% sensitivity at 65.8% specificity. We believe this biomarker could readily provide additional support to the diagnostic process., (© 2016 The Authors. Epilepsia published by Wiley Periodicals, Inc. on behalf of International League Against Epilepsy.)

The term idiopathic focal epilepsies of childhood (IFE) is not formally recognised by the ILAE in its 2010 revision (Berg et al., 2010), nor are its members and boundaries precisely delineated. The IFEs are amongst the most commonly encountered epilepsy syndromes affecting children. They are fascinating disorders that hold many "treats" for both clinicians and researchers. For example, the IFEs pose many of the most interesting questions central to epileptology: how are functional brain networks involved in the manifestation of epilepsy? What are the shared mechanisms of comorbidity between epilepsy and neurodevelopmental disorders? How do focal EEG discharges impact cognitive functioning? What explains the age-related expression of these syndromes? Why are EEG discharges and seizures so tightly locked to slow-wave sleep? In the last few decades, the clinical symptomatology and the respective courses of many IFEs have been described, although they are still not widely appreciated beyond the specialist community. Most neurologists would recognise the core syndromes of IFE to comprise: benign epilepsy of childhood with centro-temporal spikes or Rolandic epilepsy (BECTS/RE); Panayiotopoulos syndrome; and the idiopathic occipital epilepsies (Gastaut and photosensitive types). The Landau-Kleffner syndrome and the related (idiopathic) epilepsy with continuous spikes and waves in sleep (CSWS or ESES) are also often included, both as a consequence of the shared morphology of the interictal discharges and their potential evolution from core syndromes, for example, CSWS from BECTS. Atypical benign focal epilepsy of childhood also has shared electro-clinical features warranting inclusion. In addition, a number of less well-defined syndromes of IFE have been proposed, including benign childhood seizures with affective symptoms, benign childhood epilepsy with parietal spikes, benign childhood seizures with frontal or midline spikes, and benign focal seizures of adolescence. The term "benign" is often used in connection with the IFEs and is increasingly being challenged. Certainly most of these disorders are not associated with the devastating cognitive and behavioural problems seen with early childhood epileptic encephalopathies, such as West or Dravet syndromes. However, it is clear that specific, and sometimes persistent, neuropsychological deficits in attention, language and literacy accompany many of the IFEs that, when multiplied by the large numbers affected, make up a significant public health problem. Understanding the nature, distribution, evolution, risk and management of these is an important area of current research. A corollary to such questions regarding comorbidities is the role of focal interictal spikes and their enduring impact on cognitive functioning. What explains the paradox that epilepsies characterised by abundant interictal epileptiform abnormalities are often associated with very few clinical seizures? This is an exciting area in both clinical and experimental arenas and will eventually have important implications for clinical management of the whole child, taking into account not just seizures, but also adaptive functioning and quality of life. For several decades, we have accepted an evidence-free approach to using or not using antiepileptic drugs in IFEs. There is huge international variation and only a handful of studies examining neurocognitive outcomes. Clearly, this is a situation ready for an overhaul in practice. Fundamental to understanding treatment is knowledge of aetiology. In recent years, there have been several significant discoveries in IFEs from studies of copy number variation, exome sequencing, and linkage that prompt reconsideration of the "unknown cause" classification and strongly suggest a genetic aetiology. The IFE are strongly age-related, both with regards to age of seizure onset and remission. Does this time window solely relate to a similar age-related gene expression, or are there epigenetic factors involved that might also explain low observed twin concordance? The genetic (and epigenetic) models for different IFEs, their comorbidities, and their similarities to other neurodevelopmental disorders deserve investigation in the coming years. In so doing, we will probably learn much about normal brain functioning. This is because these disorders, perhaps more than any other human brain disease, are disorders of functional brain systems (even though these functional networks may not yet be fully defined). In June 2012, an international group of clinical and basic science researchers met in London under the auspices of the Waterloo Foundation to discuss and debate these issues in relation to IFEs. This Waterloo Foundation Symposium on the Idiopathic Focal Epilepsies: Phenotype to Genotype witnessed presentations that explored the clinical phenomenology, phenotypes and endophenotypes, and genetic approaches to investigation of these disorders. In parallel, the impact of these epilepsies on children and their families was reviewed. The papers in this supplement are based upon these presentations. They represent an updated state-of-the-art thinking on the topics explored. The symposium led to the formation of international working groups under the umbrella of "Luke's Idiopathic Focal Epilepsy Project" to investigate various aspects of the idiopathic focal epilepsies including: semiology and classification, genetics, cognition, sleep, high-frequency oscillations, and parental resources (see www.childhood-epilepsy.org). The next sponsored international workshop, in June 2014, was on randomised controlled trials in IFEs and overnight learning outcome measures.

The notion of 'accelerated long-term forgetting' has often been attributed to disrupted 'late' memory consolidation. Nevertheless, methodological issues in the literature have left this theory unproven, leading some to suggest such findings may be reflective of subtle acquisition or early retention deficits. This study attempts to address such issues, and also to explore which pathophysiological variables are associated with forgetting rates. Eighteen participants with temporal lobe epilepsy (TLE) and eighteen matched controls completed background neuropsychological measurement of immediate and short-delay memory that showed comparable performance, both on verbal and visual tests. Using two novel experimental tasks to measure long-term forgetting, cued recall of verbal and visuospatial material was tested 30 sec, 10 min, one day, and one week after learning. Forgetting of verbal material was found to be progressively faster during the course of a week in the TLE group. For visuospatial memory, participants in the TLE group exhibited faster early forgetting in the first 10 min after learning, as indicated by planned comparisons, with comparable forgetting rates thereafter. Our findings provide evidence for two patterns of disruption to 'early' memory consolidation in this population, occurring either at the initial delay only or continuing progressively through time. Differences in how soon after learning accelerated forgetting was detectable were related to factors associated with greater severity of epilepsy, such as presence of medial temporal lobe sclerosis (MTS) on magnetic resonance imaging (MRI) and use of multiple anti-epileptic agents., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

During Non-Rapid Eye Movement sleep (NREM) the brain is relatively disconnected from the environment, while connectedness between brain areas is also decreased. Evidence indicates, that these dynamic connectivity changes are delivered by microstructural elements of sleep: short periods of environmental stimuli evaluation followed by sleep promoting procedures. The connectivity patterns of the latter, among other aspects of sleep microstructure, are still to be fully elucidated. We suggest here a methodology for the assessment and investigation of the connectivity patterns of EEG microstructural elements, such as sleep spindles. The methodology combines techniques in the preprocessing, estimation, error assessing and visualization of results levels in order to allow the detailed examination of the connectivity aspects (levels and directionality of information flow) over frequency and time with notable resolution, while dealing with the volume conduction and EEG reference assessment. The high temporal and frequency resolution of the methodology will allow the association between the microelements and the dynamically forming networks that characterize them, and consequently possibly reveal aspects of the EEG microstructure. The proposed methodology is initially tested on artificially generated signals for proof of concept and subsequently applied to real EEG recordings via a custom built MATLAB-based tool developed for such studies. Preliminary results from 843 fast sleep spindles recorded in whole night sleep of 5 healthy volunteers indicate a prevailing pattern of interactions between centroparietal and frontal regions. We demonstrate hereby, an opening to our knowledge attempt to estimate the scalp EEG connectivity that characterizes fast sleep spindles via an "EEG-element connectivity" methodology we propose. The application of the latter, via a computational tool we developed suggests it is able to investigate the connectivity patterns related to the occurrence of EEG microstructural elements. Network characterization of specified physiological or pathological EEG microstructural elements can potentially be of great importance in the understanding, identification, and prediction of health and disease.

To evaluate the clinical associations of adult-onset photosensitivity, we studied the clinical and EEG data of patients who were referred due to a possible first seizure and who had a photoparoxysmal response on their EEG. Patients with clinical evidence of photosensitivity before the age of 20 were excluded. Of a total of 30 patients, four had acute symptomatic seizures, two had vasovagal syncope, and 24 were diagnosed with epilepsy. Nine of the 24 patients had idiopathic (genetic) generalized epilepsies and predominantly generalized photoparoxysmal response, but also rare photically-induced seizures, while 15 had exclusively, or almost exclusively, reflex photically-induced occipital seizures with frequent secondary generalization and posterior photoparoxysmal response. Other important differences included a significantly older age at seizure onset and paucity of spontaneous interictal epileptic discharges in patients with photically-induced occipital seizures; only a quarter of these had occasional occipital spikes, in contrast to the idiopathic (genetic) generalized epilepsy patients with typically generalized epileptic discharges. On the other hand, both groups shared a positive family history of epilepsy, common seizure threshold modulators (such as tiredness and sleep deprivation), normal neurological examination and MRI, a generally benign course, and good response to valproic acid. We demonstrated that photosensitivity can first occur in adult life and manifest, either as idiopathic (possibly genetic) photosensitive occipital epilepsy with secondary generalization or as an EEG, and less often, a clinical/EEG feature of idiopathic (genetic) generalized epilepsies. Identification of idiopathic photosensitive occipital epilepsy fills a diagnostic gap in adult first-seizure epileptology and is clinically important because of its good response to antiepileptic drug treatment and fair prognosis.

To explore the EEG boundary of nonconvulsive status epilepticus (NCSE) and the concept of "possible NCSE", we studied 14 consecutive patients with ≤ 2-Hz nonevolving periodic generalized epileptiform discharges (GPDs) in their first EEG after out of hospital cardiac arrest (OHCA). The pattern was associated with myoclonus in 11 patients. EG reactivity to antiseizure drugs (benzodiazepines and propofol), but without clinical improvement, was noted in 8 patients, satisfying the diagnostic criteria of "possible NCSE". Resolution of GPDs and emergence of physiological rhythms in follow-up EEGs and/or subsequent clinical improvement were noted in 6 of them, strongly suggesting that the initial slow nonevolving GPD pattern reflected NCSE significantly contributing to their coma. Background rhythms from 10 to 90% of the periods between GPDs were noted in 9 patients and appeared to correlate with reactivity of the GPD pattern to antiseizure drugs when 20% or more. Ten patients died, and four were discharged to longer care rehabilitation centers. Although based on few observations, preliminary evidence appears to indicate that in this context, nonevolving GPD frequencies as low as 0.8 Hz can reflect clinically significant NCSE and, therefore, warrant appropriate testing for possible reactivity. There is also some preliminary indication that background rhythms may be another important diagnostic and, perhaps, prognostic indicator, but this needs to be tested in large prospective studies. This article is part of a Special Issue entitled "Status Epilepticus"., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Current EEG criteria for the diagnosis of non-convulsive status epilepticus in critically ill patients with repetitive generalised or focal epileptiform discharges primarily rely on a widely accepted low cut-off frequency limit of 2.5-3 Hz for non-evolving patterns, or on discharge evolution of frequency, location or mophology. The secondary criterion is a significant clinical or EEG improvement following acute administration of a rapidly acting antiepileptic drug, such as lorazepam. We describe a comatose patient after out-of-hospital cardiac arrest, in whom very slow (1-Hz), non-evolving generalised periodic epileptiform discharges against an almost completely depressed background would suggest substantial anoxic damage and poor neurological outcome. Yet, reloading with propofol for diagnostic purposes completely dispersed generalised periodic epileptiform discharges and revealed previously absent biological activity, raising the possibility of non-convulsive status epilepticus that was subsequently confirmed. Brain MRI showed no significant anoxic brain damage and EEG improved, but the patient died from severe cardiopulmonary complications. These observations suggest that in rare cases, slow, non-evolving generalised periodic epileptiform discharges may reflect non-convulsive status epilepticus rather than diffuse irreversible cerebral anoxia, while reloading with propofol can be used as an additional secondary diagnostic criterion.

Objective: Idiopathic generalized epilepsy (IGE) has a strong genetic component, and patients with IGE show deficits in a range of frontal lobe functions. Previous studies provide hints that unaffected siblings of people with IGE may share some of these cognitive deficits, suggesting that these deficits may be genetically determined endophenotypes. Establishment of a neurocognitive endophenotype of IGE would contribute to genetic studies and increase our understanding of the pathophysiology of IGE. To identify potential neurocognitive endophenotypes of IGE, this study aimed to measure neuropsychological performance in patients with IGE, their unaffected relatives, and healthy controls., Methods: Thirty-six patients with IGE, 38 first-degree relatives, and 40 healthy controls were examined using a battery of neuropsychological tests sensitive to frontal lobe dysfunction (executive function, nonverbal reasoning, verbal generativity, response inhibition, attention, and working memory). Subject groups were compared using robust Bonferroni-corrected statistics., Results: Patients with IGE showed deficits in nonverbal reasoning, verbal generativity, attention, and working memory. Relatives exhibited a parallel profile of cognitive abilities, with significant deficits in these tasks. Patients tended to show greater impairment than relatives in these tasks., Significance: This study shows that measures of nonverbal reasoning, verbal generativity, sustained attention, and working memory are endophenotypes of IGE and offer the potential for aiding molecular genetic studies and elucidating the pathophysiology of IGE. Patients tended to demonstrate greater impairment in these tasks, possibly because of a greater genetic contribution and/or disease-related factors. A PowerPoint slide summarizing this article is available for download in the Supporting Information section here., (Wiley Periodicals, Inc. © 2014 The Authors. Epilepsia published by Wiley Periodicals, Inc. on behalf of International League Against Epilepsy.)

Objectives: To evaluate the lateralizing and localizing values of interictal focal slow activity (IFSA), single pulse electrical stimulation (SPES) and (18)FDG PET, in order to estimate their potential to complement ictal intracranial recordings and reduce prolonged monitoring in patients with temporal lobe epilepsy., Methods: The study includes 30 consecutive patients with bilateral temporal subdural electrodes and focal seizure onset. IFSA, SPES and (18)FDG PET when available, were visually assessed and their combined lateralization was based on the majority of the individual lateralizing tests., Results: In the 18 patients who had all three tests, lateralization was congruent with seizure onset areas in 15 (83%). When lateralized (15 patients), (18)FDG PET was always congruent with intracranial seizure onset. In all 12 patients without (18)FDG PET, lateralization combining IFSA and SPES was congruent with seizure onset, including two with bilateral independent seizure onset on subdural monitoring. 22 out of the 23 patients who had surgery enjoyed favorable outcome (Engel I or II)., Conclusion: Intracranial IFSA and SPES can reliably predict the side and site (mesial versus lateral temporal) of seizure onset when they lateralize to the same side., Significance: (18)FDG PET can be useful in planning electrode implantation. During intracranial recordings, IFSA and SPES have the potential to reduce telemetry time, risks and costs., (Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

An international workshop on juvenile myoclonic epilepsy (JME) was conducted in Avignon, France in May 2011. During that workshop, a group of 45 experts on JME, together with one of the founding fathers of the syndrome of JME ("Janz syndrome"), Prof. Dr. Dieter Janz from Berlin, reached a consensus on diagnostic criteria and management of JME. The international experts on JME proposed two sets of criteria, which will be helpful for both clinical and scientific purposes. Class I criteria encompass myoclonic jerks without loss of consciousness exclusively occurring on or after awakening and associated with typical generalized epileptiform EEG abnormalities, with an age of onset between 10 and 25. Class II criteria allow the inclusion of myoclonic jerks predominantly occurring after awakening, generalized epileptiform EEG abnormalities with or without concomitant myoclonic jerks, and a greater time window for age at onset (6-25years). For both sets of criteria, patients should have a clear history of myoclonic jerks predominantly occurring after awakening and an EEG with generalized epileptiform discharges supporting a diagnosis of idiopathic generalized epilepsy. Patients with JME require special management because their epilepsy starts in the vulnerable period of adolescence and, accordingly, they have lifestyle issues that typically increase the likelihood of seizures (sleep deprivation, exposure to stroboscopic flashes in discos, alcohol intake, etc.) with poor adherence to antiepileptic drugs (AEDs). Results of an inventory of the different clinical management strategies are given. This article is part of a supplemental special issue entitled Juvenile Myoclonic Epilepsy: What is it Really?, (Copyright © 2013 Elsevier Inc. All rights reserved.)

Juvenile myclonic epilepsy (JME) can be firmly diagnosed by a careful interview of the patient focusing on the seizures and by the EEG with the help, if necessary, of long-term video-EEG monitoring using sleep and/or sleep deprivation. Background activity is normal. The interictal EEG shows diffuse or generalized spike-wave (SW) and polyspike-wave (PSW) discharges. In some patients, non-specific changes or misleading features such as focal changes are found. Changes are mostly seen at sleep onset and at awakening. Provoked awakenings are more likely to activate interictal paroxysmal abnormalities than spontaneous awakenings. The presence of a photoparoxysmal response with or without myoclonic jerks (MJ) is common (30% of the cases). Myoclonic jerks are associated with a discharge of fast, irregular, generalized PSWs that predominate anteriorly. Myoclonic jerks appear to be associated with rhythmic EEG (spike) potentials at around 20Hz. These frequencies are in the range of movement-related fast sensorimotor cortex physiological rhythms. The application of jerk-locked averaging technique has provided findings consistent with a cortical origin of MJ. Paired TMS (transcranial magnetic stimulation) studies showed a defective intracortical inhibition, due to impaired GABA-A mediated mechanisms. In this review, we present the EEG characteristics of JME with particular emphasis on the pathophysiology of MJ and on the role of sleep deprivation on interictal and ictal changes., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Background and Purpose: To describe the epidemiology and associations of poststroke epilepsy (PSE) because there is limited evidence to inform clinicians and guide future research., Methods: Data were collected from the population-based South London Stroke Register of first strokes in a multiethnic inner-city population with a maximum follow-up of 12 years. Self-completed forms and interviews notified study organizers of epilepsy diagnosis. Kaplan-Meier methods and Cox models were used to assess associations with sociodemographic factors, clinical features, stroke subtype, and severity markers., Results: Three thousand three-hundred ten patients with no history of epilepsy presented with first stroke between 1995 and 2007, with a mean follow-up of 3.8 years. Two-hundred thirteen subjects (6.4%) had development of PSE. PSE incidence at 3 months and 1, 5, and 10 years were estimated at 1.5%, 3.5%, 9.0%, and 12.4%, respectively. Sex, ethnicity, and socioeconomic status were not associations, but markers of cortical location, including dysphasia, visual neglect, and field defect, along with stroke severity indices at presentation, including low Glasgow Coma Scale, incontinence, or poor function on Barthel Index, were associated with PSE on univariate analysis. Young age was independently associated with PSE, affecting 10.7% of patients aged <65 years and 1.6% >85 years (P≤0.001) on 10-year estimates. Independent predictors of PSE also included visual neglect, dysphasia, and stroke subtype, particularly total anterior circulation infarcts. Dysarthria was associated with reduced incidence., Conclusions: PSE is common, with risk continuing to increase outside the acute phase. Young age, cortical location, larger lesions, and hemorrhagic lesions are independent predictors.

Background: Prognostication following anoxic coma relies on clinical assessment and is assisted by neurophysiology. A non-evolving EEG spike burst/isoelectric suppression pattern after the first 24 hours almost invariably indicates poor outcome, while an evolving pattern implies nonconvulsive status epilepticus (NCSE) that may "hide" surviving brain activity and is amenable to treatment., Case Study: We present the case of a 53-year-old woman who had a witnessed out-of-hospital ventricular fibrillation cardiac arrest, was resuscitated by paramedics, but remained comatose. An EEG, performed 36 hours post-insult, showed an unremitting, non-evolving, unresponsive 2-6 Hz high-voltage spike burst/isoelectric suppression pattern, which remained unchanged at 96 hours post-insult, following therapeutic hypothermia. During this period, she was completely off sedation and taking triple antiepileptic treatment, without systemic confounding disorders. Although the initial pattern was indicative of poor neurological outcome, she eventually made meaningful functional recovery; the last EEG showed satisfactory background rhythms and stimulus-induced epileptiform discharges without seizures., Conclusion: In post-anoxic coma, non-evolving >2 Hz spike burst/isoelectric suppression pattern may still reflect NCSE and therefore should be considered in the diagnostic EEG criteria for NCSE. Such borderline patterns should not dissuade physicians from intensifying treatment until more confident prognostication can be made.

Background: The outcome for patients with hypoxic-ischaemic brain injury (HIBI) is often poor. It is important to establish an accurate prognosis as soon as possible after the insult to guide management. Clinical assessment is not reliable and ancillary investigations, particularly imaging and EEG, are needed to understand the severity of brain injury and the likely outcome., Methods: We undertook a retrospective study of 39 patients on an intensive therapy unit (ITU) with HIBI who were referred for MRI. The patients were seen consecutively >57 months. HIBI was due to a variety of insults causing cardiac arrest, hypoperfusion or isolated hypoxia., Results: The outcome was poor, 29 patients died, 7 were left severely disabled and only 3 made a good recovery. Characteristic imaging changes were seen on MRI. These included extensive changes in the cortex and the deep grey matter present on diffusion-weighted imaging (DWI) and T2-weighted imaging within 6 days of the insult. In other patients, different patterns of involvement of the cortex and basal ganglia occurred. There was no significant difference in the outcome or imaging appearances according to aetiology. A poor prognosis was consistently associated with a non- or poorly responsive EEG rhythm and the presence of periodic generalized phenomena with a very low-voltage background activity., Conclusion: In this retrospective study of patients with HIBI, MRI and EEG provided valuable information concerning prognosis.

Introduction: We assessed the clinical impact of replacing standard neurophysiologic testing with a hand-held device (Mediracer) for diagnosis of carpal tunnel syndrome (CTS)., Methods: One hundred patients (200 hands) with suspected CTS were studied by blinded assessors [Hand-therapist (HT)1 and Consultant Neurophysiologist] using the Mediracer, followed by standard neurophysiologic testing. To simulate testing by personnel without neurological training, Mediracer recordings were analyzed separately by an assessor who had not seen the patients (HT2)., Results: Correlation of the CTS grades was 0.94 for the results obtained by HT1, and 0.87 for HT2. The sensitivity and specificity of the Mediracer was 0.85 and 0.9, respectively, by HT1, and 0.84 and 0.89 for HT2. Nine patients had conditions other than CTS, and 35 patients were judged to require further investigation., Conclusions: The Mediracer should only be used in patients with typical CTS symptoms and signs and no muscle wasting who have had careful neurological assessment., (Copyright © 2012 Wiley Periodicals, Inc.)

Purpose:   To better understand the nature of the focal spike-wave discharges (FSWDs) and focally led generalized spike-wave discharges (GSWDs) in typical childhood absence epilepsy (CAE) and by implication their nosologic and taxonomic significance., Methods:   Twenty-four abnormal video-electroencephalography (EEG) studies from 13 consecutive children with CAE and good response to appropriate antiepileptic drugs (AEDs) were analyzed. We studied the association between the topography of absence onset and the ictal automatisms, and the topographic correlation between FSWDs and GSWDs and their respective behavior during hyperventilation and the different states of phasic and nonphasic non-rapid eye movement (NREM) sleep. GSWDs were considered as of "focal" onset if a lead-in could be visibly recognized at a paper speed of 60 mm/s, and were classified by their topography., Key Findings:   (1) Multifocal absences occurred in 10 children; anterior onset was noted in 81 absences (73.6%) from 12 children and posterior in 18 (16.4%) from 7 children; there was no association between topography of absence onset and ictal automatisms; (2) FSWDs occurred in 85% of children and were multifocal in 73% of them; 85% of FSWDs were anterior and 14% posterior; (3) there was good topographic association between FSWDs and the leading spike of GSWDs of "focal" onset in all children with FSWDs; (4) both FSWDs and GSWDs increased during hyperventilation; (5) FSWDs occurred mainly during noncyclical NREM sleep and during periods of reduced vigilance of cyclical NREM sleep, whereas GSWDs occurred during the periods of enhanced vigilance of NREM sleep; GSWDs occurred significantly more frequently than FSWDs at the transition from reduced to enhanced vigilance of NREM sleep., Significance:   Our findings suggest that in CAE focal EEG paroxysms reflect a system of multifocal nonlocalizing electrically unstable cortical areas that under the facilitatory influence of exogenous or endogenous factors like sleep instability can foster a corticothalamic response of sufficient strength to generate 3-Hz GSWDs that are conditionally sustainable and potentially ictal. FSWDs can be viewed as incomplete forms of the GSWDs; together they define the EEG identity of idiopathic "generalized" epileptogenesis., (Wiley Periodicals, Inc. © 2012 International League Against Epilepsy.)

Objective: To investigate the spatiotemporal course of interictal spikes in Panayiotopoulos syndrome (PS), and in particular whether seemingly independent extra-occipital spikes are truly autonomous or secondary, triggered by occipital spikes., Methods: Seven children with the most representative interictal spike patterns on visual analysis were studied. Five had a single focus (occipital in two, suggestive of posterior to anterior spike propagation in two, and frontal) and two had two foci over the posterior and the anterior areas independently. Spikes were marked, clustered and waveform - averaged, and mapped on electrode space., Results: The patterns of spatial and temporal dynamics of the interictal spikes were not stereotypical for any brain area, including the occipital lobe. Some of the anterior and the posterior spikes remained focal or showed little spread, but others appeared to propagate to the opposite direction (occipital to frontal and vice versa)., Conclusions: In PS all cerebral locations are able to spontaneously and independently generate and propagate interictal spikes, indicating that PS is a multifocal epileptic syndrome., Significance: Confirmation of the multifocal character of PS improves clinical diagnosis and challenges our current taxonomic concepts by expanding the anatomical boundaries of a distinct focal epilepsy phenotype from lobar to system., (Crown Copyright 2010. Published by Elsevier Ireland Ltd. All rights reserved.)

The purpose of this review is to provide guidance for appropriate diagnosis and management of idiopathic childhood occipital epilepsy of Gastaut. The typical clinical features are visual seizures that typically consist of brief elementary visual hallucinations, which are mainly multicolored and circular. Ictal blindness and deviation of the eyes are also common symptoms. The seizures are usually frequent and diurnal. The electroencephalography is the only investigation with abnormal results, showing occipital spikes and often occipital paroxysms demonstrating fixation-off sensitivity. Brain magnetic resonance imaging is used to exclude symptomatic occipital epilepsy. Patients usually respond well to antiepileptic medication and about two-thirds remit by the age of 16 years. Idiopathic childhood occipital epilepsy of Gastaut is frequently misdiagnosed as migraine with visual aura, acephalgic, or basilar migraine. Differentiation from symptomatic occipital epilepsy, particularly when children are otherwise normal, can be difficult. Most children need prophylactic antiepileptic medication.

Purpose: Epileptiform discharges (EDs) may be part of the internal arousing stimuli that affect the quality of sleep in patients with epilepsies. We studied the association between EDs and sleep phasic phenomena, and its relevance to seizure control in 19 patients with juvenile myoclonic epilepsy (JME)., Methods: We analyzed the first cycle of non-REM (rapid eye movement) sleep in 22 sleep-deprived electroencephalography (EEG) studies and classified EDs within the cyclical alternating pattern (CAP) frame, grouping separately the EDs that occurred at the transition between phases (B to A and A to B)., Results: Within CAP periods, 36.7% of EDs occurred in A phase, 26.7% in B phase, 31.5% at "B to A" transition, and 3% at "A to B" transition. Poor seizure control was strongly associated with increased EDs in phase B (p = 0.0016) and at the "B to A" transition (p = 0.002), but marginally with increased EDs in phase A (p = 0.03). Focal spikes were increased in phase B., Discussion: EDs are facilitated by increased vigilance (A phase), but they may also enhance CAP cycling by generating A phases when those that occur at the "B to A" transition are interpreted as successfully breaking through the state of reduced arousal (phase B) because of increased epileptic pressure. This promotes sleep instability and further fosters epileptic activity, and conceivably seizures. This hypothesis is also supported by the strong correlation between EDs during phase B (including "B" and "B to A") and poor seizure control. The enhanced nonlocalizing focal spikes in phase B may reflect successful inhibition of generalized EDs.

Aims: To study clinical features of adult patients with idiopathic generalized epilepsy with special attention to suicidal behavior., Methods: We reviewed the medical records of 145 consecutive adult patients with electro-clinically confirmed idiopathic generalized epilepsy and identified those with a history of at least one attempted suicide. Clinical variables in relation to their epilepsy and psychiatric conditions were analyzed., Results: Seven patients (4.8%) had a history of suicide attempts with drug overdose, and one of these patients committed suicide after multiple attempts. All attempts were made interictally without direct relation to their epileptic seizures. All had at least one co-morbid mental disorder (two with dual diagnosis). Although their psychiatric diagnoses varied, they all appeared to have increased emotional instability and poor impulse control. Only one patient's attempt was directly associated with her co-morbid depression., Conclusions: Physicians managing people with epilepsies should be aware of psychiatric disturbances and suicidal behavior in idiopathic generalized epilepsy.

Purpose: To define the spectrum of the epileptic syndromes and epilepsies (other than the idiopathic epilepsies of childhood with occipital paroxysms) that can be associated with fixation-off sensitivity (FOS), delineate the electrographic types of FOS abnormalities and identify the patterns that can be associated with clinical seizures, and examine whether there may be a pure form of fixation-off sensitive epilepsy., Methods: We reviewed the clinical and video EEG data of all our patients with FOS over the last 12 years. Children with idiopathic focal epilepsies and occipital EEG paroxysms were excluded., Results: From January 1995 to December 2006, 19 of about 8,500 patients had had one or more video-EEGs with FOS, yielding an approximate incidence of 0.2%. From the 14 patients with full clinical and EEG data available, 12 had various epilepsies that included IGE phenotypes (7), symptomatic or probably symptomatic focal (3), cryptogenic generalised (1), and adult onset idiopathic photosensitive occipital (1), and two had no seizures. Seven patients (50%) were photosensitive. FOS EEG abnormalities were occipital in six patients, generalised in eight, and generalised with posterior emphasis in two patients. Seven of these patterns were associated with habitual seizures in seven patients, but actual FOS-induced seizures (absences) were documented with video EEG in only one patient; three others had some historical evidence suggesting that, under some circumstances, their FOS EEG abnormalities might generate clinical seizures., Conclusions: Despite the association of FOS with generalised and focal, symptomatic and cryptogenic and mild or pharmaco-resistant epilepsies, closer analysis of our data, and supportive evidence from functional imaging and physiological observations on alpha rhythm generation, disclose a prominent role of the occipital areas, even when FOS EEG abnormalities and seizures are ostensibly generalised. Although FOS appears to be of relatively low epileptogenicity, an electroclinical profile of pure FOS epilepsy may exist [Published with video sequences].

The purpose of the present study was to explore the brain regions involved in human episodic memory by correlating unilateral memory performance estimated by the intracarotid amobarbital test (IAT) and interictal cerebral metabolism measured by [(18)F]fluorodeoxyglucose positron emission tomography ([(18)F]FDG-PET). Using this method, regional alterations of cerebral metabolism associated with epilepsy pathophysiology are used to predict hemisphere-specific episodic memory function, hence, investigate the differential distribution of memory in each hemisphere. Sixty-two patients with unilateral temporal lobe epilepsy (35 left and 27 right) were studied using [(18)F]FDG-PET with complementary voxel-based statistical parametric mapping (SPM) and region-of-interest (ROI) methods of analysis. Positive regression was analyzed in SPM with a series of different thresholds (p = .001, .01 or .05) with a correction to 100 voxels. IAT memory performance in which left hemisphere was tested by right-sided injection of amobarbital correlated with [(18)F]FDG uptake in left lateral and medial temporal regions, and in the left ventrolateral frontal cortex. Right IAT memory performance correlated with [(18)F]FDG uptake in the right inferior parietal lobule, right dorsolateral frontal cortex, right precentral gyrus, and caudal portion of the right anterior cingulate cortex. ROI analysis corroborated these results. Analyses carried out separately in patients with left (n = 50) and nonleft (n = 12) dominance for language showed that in the nonleft dominant group, right IAT scores correlated with right fronto-temporal regions, whereas left total memory scores correlated with left lateral and medial temporal regions. The findings indicate that (i) episodic memory is subserved by more widespread cortical regions beyond the core mesiotemporal lobe memory structures; (ii) there are different networks functional in the two hemispheres; and (iii) areas involved in memory may be different between patients with left and nonleft dominance for language, particularly in the right hemisphere.

Purpose: To define the relationship between two syndromes of idiopathic generalized epilepsy (IGE) with apparently similar phenotypes: The form with generalized tonic-clonic seizures only (IGE-GTCS) and that with phantom absences (IGE-PA)., Methods: We compared the electroclinical features of 33 consecutive patients with GTCS and generalized spike wave (GSW); 18 had only GTCS and were diagnosed as IGE-GTCS, and 15 had hitherto unnoticed mild absences on the electroencephalography (EEG) and were diagnosed as IGE-PA. All patients were subjected to the same diagnostic workout, including video EEG during hyperventilation with breath counting (HBC). Patients with a clinical history of absences or myoclonic seizures were excluded., Results: PA were easily identified with the first or second EEG in 14 of 15 patients with IGE-PA and always with sleep-deprived EEGs; conversely, PA did not occur in the IGE-GTCS patients despite using more EEGs. GTCS were twice as frequent in the IGE-GTCS group and tended to occur on awakening, whereas episodes of absence status affected twice as many patients with IGE-PA. The hereditary risk was 30% in the IGE-GTCS and 6.7% in IGE-PA. GSW had a strong polyspike component in IGE-PA and were briefer in IGE-GTCS. There is no evidence for a maturational influence on the duration of GSW in either syndrome., Conclusion: Our findings clearly indicate that IGE-GTCS and IGE-PA are two distinct IGE syndromes and emphasize the role of PA for patients' diagnosis and management and for syndromic classification. They also appear to validate HBC as a simple, sensitive, and pragmatic method for the clinical identification of typical absences.

We reviewed the medical records of 157 adult (18 years) patients with firmly diagnosed idiopathic generalized epilepsy (IGE) to investigate the extent and the type of psychiatric comorbidity and its relationship to various IGE syndromes and other epilepsy-related neurobiological factors. Forty-one patients (26.1%, 14 men and 27 women, median age: 34.0 years, range: 18-68, mean: 36.5) had comorbid mental disorders according to the 10th revision of the International Classification of Diseases (ICD-10) criteria, with four patients having a dual diagnosis. Mood disorders were the most common comorbid mental disorder (46.7%), followed by anxiety-panic disorder (26.7%). Comorbid psychiatric disorders occurred in all syndromes and in association with all seizure types, and, as in focal epilepsies, seizure control was significantly better in patients without psychiatric comorbidity (40.5% vs 19.5%, chi(2)(1)=5.873, P=0.015).

Purpose: To discuss and propose a definition of autonomic status epilepticus (SE), describe its clinical and EEG features, and review what is known about its epidemiology, pathophysiology, differential diagnosis, and management., Methods: An international consortium of established researchers in the field was identified from their published work, agreed the purpose of the project, searched the literature, and, by use of e-mail communication, agreed the consensus document., Results: Autonomic SE is a condition lasting at least 30 min and characterized by epileptic activity causing altered autonomic function of any type at seizure onset or in which manifestations consistent with altered autonomic function are prominent (quantitatively dominant or clinically important) even if not present at seizure onset. It is best described, and probably most commonly encountered in children, with Panayiotopoulos syndrome. However, it also occurs in children with symptomatic epilepsies and, exceptionally, in adults. Its pathogenesis and most appropriate management are poorly understood., Conclusions: It is hoped that this document will help clinical recognition of Autonomic SE, reduce misdiagnosis, and promote further interest and studies into what has been a relatively neglected area.

As a result of the converging evidence from multiple large independent studies, Panayiotopoulos syndrome (PS) is now formally recognized as a distinct clinical entity within the spectrum of benign focal epilepsies of childhood. Clinically, PS is manifested by predominantly autonomic seizures and electrographically with multifocal interictal spikes, while the few published ictal recordings have documented onsets of variable lobar topography. These typical electroclinical features do not allow straightforward assignment to a distinctive cortical area, rendering the term "focal"--as we currently understand it--problematic. This is a critical review of the clinical and EEG features of PS, focusing on those characteristics that may shed some light on its so far elusive pathophysiology. We also explore its electroclinical similarities to other idiopathic "focal" epilepsies and its differences to symptomatic focal epilepsies that may also manifest with autonomic ictal symptoms and signs. This methodology allows the formation of a rational hypothesis on the pathophysiology of PS that seems to be emerging as a good model for the so-called "system" (nonsymptomatic) epilepsies, with potentially important taxonomic implications.

Euphoric or hedonic theta hypersynchrony appears to be an unusual finding in the electroencephalography of the child, and it has been rarely reported. This case report presents a 4-year-old child who responded to pleasurable stimulation with a robust, diffuse theta activity, and also samples some of the thoughts that such a response can generate. [Published with video sequences].

Purpose: Panayiotopoulos syndrome (PS) is a type of benign childhood partial epilepsy that is frequently associated with abundant multifocal spikes other than main occipital spikes on the EEG. In this study, we investigated the characteristic features of dipoles in PS., Methods: We performed dipole analysis of the interictal occipital spike discharges seen in 10 children with PS (group A) and in 10 children with other types of symptomatic localization-related epilepsy (group B). We analyzed the dipoles of the averaged spike in each patient., Results: In group A, the averaged occipital spikes in each patient showed dense dipole locations in the mesial occipital area; in group B, widely scattered dipole locations were observed. In Group A, the geometric centers of the dipoles at each time point (such as at the main negative peak and before or after the main peak) were estimated in the neighboring locations. In contrast, they tended to be scattered in group B., Conclusions: Our study reveals that PS has high dipole stability, similar to that of rolandic epilepsy. From the electroencephalographic view, this seems to indicate a close link between these two syndromes.

This review concentrates on the principles of the clinical and electroencephalogram diagnosis of idiopathic generalized epilepsies and their treatment. The electroclinical variability of the main seizure types is detailed and particular emphasis is placed on the differential diagnosis from other seizures and nonepileptic conditions that is essential for the optimal management of these patients. The authors review the various idiopathic generalized epilepsy subsyndromes and conditions that are included in both the 1989 International League Against Epilepsy classification system and the recently proposed International League Against Epilepsy scheme, but also syndromes and forms that have not been formally recognized. Finally, the authors describe the principles of antiepileptic drug treatment with the old and newer drugs, and their specific indications and contraindications in the various syndromes and seizure types.

We describe a neurologically and developmentally normal child with infrequent seizures characterized by emetic symptoms and other autonomic phenomena and interictal spikes that satisfy the diagnostic criteria of Panayiotopoulos syndrome (PS). Two video/EEG recordings, taken a year apart, revealed prolonged autonomic seizures and other subtle behavioral changes, suggesting that episodes of nonconvulsive status epilepticus in PS may be more frequent than appreciated.

This study investigated the social cognitive functioning of patients with frontal lobe epilepsy (FLE), using a range of procedures that have shown impairments in patients following focal prefrontal brain lesions. Fourteen participants with FLE were compared with 14 healthy controls on story tests of theory of mind (ToM), faux pas appreciation, mental and physical state cartoon humor appreciation, facial emotional recognition, and the ability to perceive eye gaze expression. They were not impaired on story tests of ToM and showed only a trend toward impairment on a test of faux pas appreciation. They were impaired on humor appreciation, with both mental and physical state cartoons, and on their recognition of facial emotion and perception of eye gaze expression. Hence the patients with FLE exhibited impairments on tests of social cognition following a distinct pattern, with relatively preserved ToM, but impaired humor appreciation and ability to detect emotional expression.

Panayiotopoulos syndrome (PS) is a type of benign childhood partial epilepsy, which has a good prognosis despite the fact that it is frequently associated with abundant multifocal spikes on the electroencephalography (EEG). We investigated whether stable dipoles, as seen in rolandic epilepsy, were also present in PS. We performed dipole analysis of the interictal spike discharges seen in the interictal EEGs of eight children with PS. We chose more than 10 spikes for each kind of spike, and investigated whether or not more than three of these spikes showed consistently stable dipole locations. (1) We observed 15 different kinds of spikes in various regions in the EEGs of the eight children. (2) Twelve of the 15 kinds of spikes had dipoles with a high goodness of fit. Furthermore, 14 of the 15 spikes had stable dipoles with similar locations for more than three individual spikes. (3) Fourteen of the 15 spikes, including frontal spikes, showed dense dipole locations in the mesial occipital area. Thirteen of these 14 spikes also showed other dipole locations in the rolandic area and/or the vertex (Cz). Our study revealed that the various types of spikes observed in PS have similar and stable dipole locations. The dipoles showing high stability, were located in the mesial occipital area, and were accompanied by dipoles located in the rolandic area. The stability and location of these dipoles indicate that there may be a pathogenetic link between PS and rolandic epilepsy.

This article concentrates on the role of electroencephalograms (EEGs) in the diagnosis and management of patients with idiopathic generalized epilepsies (IGEs). We review the morphologic and behavioral characteristics of the interictal and ictal EEG markers of IGE that should guide recording strategies to augment its diagnostic yield, and we attempt to delineate those particular features that may be relevant to different IGE syndromes. We also explore the electrographic boundaries between IGEs and cryptogenic/symptomatic generalized and focal epilepsies, and focal/secondary generalized epilepsies, with particular relevance to the phenomena of focal abnormalities and secondary bilateral synchrony, commenting on possible diagnostic pitfalls and areas of uncertainty.

Purpose: To assess the contribution of the EEG technologists in the diagnosis of children with epileptic seizures., Methods: We analysed the clinical information obtained by the EEG technologists from children with epileptic seizures and their parents, and assessed its value for the generation of a clinically useful EEG report and a plausible electroclinical diagnosis. Interviews were based on a qualitative questionnaire, and were videotaped. We focused on Panayiotopoulos syndrome (PS) because it has a high rate of misdiagnosis, usually for encephalitis or other severe cerebral insults., Results: Between 1998 and 2001, 424 EEG were performed in 308 children aged 1-14 years, of whom 228 (74%) had one or more epileptic seizures. We diagnosed PS in 14 children (6.1%), mainly based on clinical information. Three other had symptomatic ictal vomiting. In 9 of the 14 children with PS, diagnosis was achieved by the information collected by the EEG technologist. Five of these children were being treated for encephalitis, and management was altered accordingly. In a further three children the diagnosis of PS was confirmed., Conclusion: These findings demonstrate that the contribution of the EEG technologists to the diagnosis of people with epilepsies can expand well beyond their established role of recording and describing an EEG. We propose that technologists should be actively involved in prospective electroclinical studies if carefully designed protocols are used.

Purpose: To determine the characteristics and the clinical significance of focal slow activity and its association with focal epileptogenesis in patients with temporal lobe epilepsy (TLE)., Methods: We analyzed the interictal EEGs of 141 patients who had temporal lobe resections for intractable focal seizures and correlated the findings with pathologic changes and outcome. The pathologic changes were categorized into medial temporal sclerosis, tumors, and nonspecific changes., Results: Lateralized slow activity was found in 66% of the patients, and it was mainly temporal, of delta frequency and irregular morphology. None of its characteristics, including quantity and reactivity to eye opening, was substrate specific. It was highly concordant with temporal spiking (60%), without any difference across the three groups, but provided additional information in 19 (15%) patients who had no lateralizing spikes. The effect of sleep also was similar in all three groups and included transition of slow waves into spikes. Lateralized slow activity to the side of the operation was significantly associated with favorable outcome only in the group with nonspecific pathology (p = 0.008), regardless of the presence, laterality, or topography of spikes., Conclusions: Our findings suggest that in patients with TLE whose brain magnetic resonance imaging (MRI) is either normal or suggestive of medial temporal sclerosis, interictal temporal slow activity has a lateralizing value similar to that of temporal spiking. Its association with a favorable outcome in patients with nonspecific pathology also suggests that candidates with lateralizing temporal delta and normal MRI should not be barred from further preoperative assessment.

Objective: To compare the neuropsychological effects of temporal lobectomy (TL) and amygdalohippocampectomy (AH), depending on whether the patients had passed or failed the Wada test., Methods: We compared changes in neuropsychological scores in patients who underwent TL (n = 91) or AH (n = 15), and had passed or failed the Wada test. Comparisons were carried out in all 106 patients and among the 20 patients who failed the Wada test (12 who had TL and 8 who had AH)., Results: No patient became globally amnesic after surgery. Among all patients, no differences were found in pre-surgical or change scores (percentage of change after surgery compared with preoperative values) of neuropsychological tests between patients who underwent TL or AH. Among patients who failed the Wada test, those in the TL group showed higher visual memory impairment (p<0.05). There was a strong trend suggesting that TL is associated with higher verbal memory deficits than AH (p = 0.07). Of those TL patients who failed the Wada test, the contralateral Wada score correlated with change scores in verbal intelligence quotient (p<0.01), and there was a strong trend towards a correlation with the logical memory immediate recall version subtest of the Wechsler Memory Scale (p = 0.06)., Conclusions: No profound changes in intelligence quotient or memory scores were found after TL or AH. Nevertheless, patients who underwent TL and failed the Wada test showed more deficits than those who passed the test or those who had AH. The presence of a correlation between contralateral Wada scores and verbal deficits in TL patients who failed the Wada test but not among AH patients suggests that, if temporal surgery is required, AH might be preferred to TL in patients who fail the Wada test.

Medial temporal lobe structures are known to play a major role in memory processing. Recent work has revealed that extratemporal structures (e.g. the frontal lobe and thalamus) may also be important in memory function. In candidates for epilepsy surgery, particularly in those with temporal lobe seizures, presurgical evaluation of memory function is essential, since seizures may originate in the neural substrate that is critical for memory. In this article, we review the tools used for presurgical evaluation and their contribution to the understanding of memory function, focusing on the Wada test, [18F]fluorodeoxy-glucose positron emission tomography ([18F]FDG-PET) and functional magnetic resonance imaging (fMRI). We also explore perspectives on future studies that may elucidate the role of the temporal and extratemporal structures in memory function and the mechanisms of cerebral plasticity.