Drug-responsive versus drug-refractory mesial temporal lobe epilepsy: a single-center prospective outcome study.

Objectives: To evaluate clinical, electrophysiological, and neuroradiological factors which correlate with the prognosis in patients with mesial temporal lobe epilepsy (MTLE). Methods: This was a single-center prospective outcome study in patients with MTLE. The patients' family history, clinical characteristics, neurophysiological data (electroencephalography - EEG), neuroimaging, antiepileptic therapy, and outcome were collected and analyzed. The population was divided into four groups depending on the frequency of the seizures when they attended their last follow up. All variables and outcome measures were compared between the four groups. Results: In total 83 consecutive patients were included within the four groups. Group 1 (seizure-free) consisted of 7 patients, (9%), Group 2 (rare seizures) consisted of 15 patients (18%), Group 3 (often seizures) consisted of 30 patients (36%), and Group 4 (very often seizures) consisted of 31 patients (37%). The groups did not differ significantly in demographic characteristics. There was a strong positive correlation between resistance to therapy and sleep activation on EEG (p = 0.005), occurrence of focal to bilateral seizures (p = 0.007), automatisms (p = 0.004), and the number of previously used antiepileptic drugs (AEDs) (p = 0.002). There was no association between febrile convulsions (FC), hippocampal sclerosis (HS), and the outcome that was found. Conclusion: MTLE is a heterogeneous syndrome. Establishing the factors responsible for, and associated with, drug resistance is important for optimal management and treatment, as early identification of drug resistance should then ensure a timely referral for surgical treatment is made. This prospective study shows that sleep activation on EEG, ictal automatisms, occurrence of focal to bilateral tonic-clonic seizures, and increased number of tried AEDs are negative prognostic factors.

Data fusion for paroxysmal events' classification from EEG.

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.

Forgetting in temporal lobe epilepsy: When does it become accelerated?

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.

Consensus on diagnosis and management of JME: From founder's observations to current trends.

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?

Incidence and associations of poststroke epilepsy: the prospective South London Stroke Register.

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.

Idiopathic childhood occipital epilepsy of Gastaut: a review and differentiation from migraine and other epilepsies.

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.

Suicide attempts in adult patients with idiopathic generalized epilepsy.

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.

Hemisphere-specific episodic memory networks in the human brain: a correlation study between intracarotid amobarbital test and [(18)F]FDG-PET.

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.

Benign childhood focal epilepsies: assessment of established and newly recognized syndromes.

A big advance in epileptology has been the recognition of syndromes with distinct aetiology, clinical and EEG features, treatment and prognosis. A prime and common example of this is rolandic epilepsy that is well known by the general paediatricians for over 50 years, thus allowing a precise diagnosis that predicts an excellent prognosis. However, rolandic is not the only benign childhood epileptic syndrome. Converging evidence from multiple and independent clinical, EEG and magnetoencephalographic studies has documented Panayiotopoulos syndrome (PS) as a model of childhood autonomic epilepsy, which is also common and benign. Despite high prevalence, lengthy and dramatic features, PS as well as autonomic status epilepticus had eluded recognition because emetic and other ictal autonomic manifestations were dismissed as non-epileptic events of other diseases. Furthermore, PS because of frequent EEG occipital spikes has been erroneously considered as occipital epilepsy and thus confused with the idiopathic childhood occipital epilepsy of Gastaut (ICOE-G), which is another age-related but rarer and of unpredictable prognosis syndrome. Encephalitis is a common misdiagnosis for PS and migraine with visual aura for ICOE-G. Pathophysiologically, the symptomatogenic zone appears to correspond to the epileptogenic zone in rolandic epilepsy (sensory-motor symptomatology of the rolandic cortex) and the ICOE-G (occipital lobe symptomatology), while the autonomic clinical manifestations of PS are likely to be generated by variable and widely spread epileptogenic foci acting upon a temporarily hyperexcitable central autonomic network. Rolandic epilepsy, PS, ICOE-G and other possible clinical phenotypes of benign childhood focal seizures are likely to be linked together by a genetically determined, functional derangement of the systemic brain maturation that is age related (benign childhood seizure susceptibility syndrome). This is usually mild but exceptionally it may diverge to serious epileptic disorders such as epileptic encephalopathy with continuous spike and wave during sleep. Links with other benign and age-related seizures in early life such as febrile seizures, benign focal neonatal and infantile seizures is possible. Overlap with idiopathic generalized epilepsies is limited and of uncertain genetic significance. Taking all these into account, benign childhood focal seizures and related epileptic syndromes would need proper multi-disciplinary re-assessment in an evidence-based manner.

Idiopathic epilepsy with generalized tonic-clonic seizures only versus idiopathic epilepsy with phantom absences and generalized tonic-clonic seizures: one or two syndromes?

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.

Psychiatric comorbidity in adult patients with idiopathic generalized epilepsy.

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).

Panayiotopoulos syndrome: an important electroclinical example of benign childhood system epilepsy.

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.

Autonomic status epilepticus in Panayiotopoulos syndrome and other childhood and adult epilepsies: a consensus view.

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.

Euphoric (hedonic) theta hypersynchrony in early childhood.

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].

EEG dipole characteristics in Panayiotopoulos syndrome.

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.