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Epilepsia Apr 2017The International League Against Epilepsy (ILAE) presents a revised operational classification of seizure types. The purpose of such a revision is to recognize that some...
The International League Against Epilepsy (ILAE) presents a revised operational classification of seizure types. The purpose of such a revision is to recognize that some seizure types can have either a focal or generalized onset, to allow classification when the onset is unobserved, to include some missing seizure types, and to adopt more transparent names. Because current knowledge is insufficient to form a scientifically based classification, the 2017 Classification is operational (practical) and based on the 1981 Classification, extended in 2010. Changes include the following: (1) "partial" becomes "focal"; (2) awareness is used as a classifier of focal seizures; (3) the terms dyscognitive, simple partial, complex partial, psychic, and secondarily generalized are eliminated; (4) new focal seizure types include automatisms, behavior arrest, hyperkinetic, autonomic, cognitive, and emotional; (5) atonic, clonic, epileptic spasms, myoclonic, and tonic seizures can be of either focal or generalized onset; (6) focal to bilateral tonic-clonic seizure replaces secondarily generalized seizure; (7) new generalized seizure types are absence with eyelid myoclonia, myoclonic absence, myoclonic-atonic, myoclonic-tonic-clonic; and (8) seizures of unknown onset may have features that can still be classified. The new classification does not represent a fundamental change, but allows greater flexibility and transparency in naming seizure types.
Topics: Epilepsy; Humans; International Agencies; Seizures; Societies, Medical; Terminology as Topic
PubMed: 28276060
DOI: 10.1111/epi.13670 -
The Cornell Veterinarian Apr 1981Recent developments in the understanding of the cellular events in focal seizures are described. This is followed by a discussion of the pathogenesis of neuronal... (Review)
Review
Recent developments in the understanding of the cellular events in focal seizures are described. This is followed by a discussion of the pathogenesis of neuronal hyperexcitability, the mechanism of spread of the seizure discharge and the mechanisms involved in seizure termination. The pathophysiology of generalized seizures is described in terms of theories of the site of origin of the seizure discharge and possible mechanisms of the clinical phenomena associated with this discharge.
Topics: Animals; Brain; Cats; Cell Membrane; Cerebral Cortex; Electric Stimulation; Electroencephalography; Epilepsies, Partial; Epilepsy; Humans; Neural Pathways; Neurons; Seizures; Synaptic Transmission
PubMed: 6260428
DOI: No ID Found -
Clinical and experimental insight into pathophysiology, comorbidity and therapy of absence seizures.Brain : a Journal of Neurology Aug 2020Absence seizures in children and teenagers are generally considered relatively benign because of their non-convulsive nature and the large incidence of remittance in... (Review)
Review
Absence seizures in children and teenagers are generally considered relatively benign because of their non-convulsive nature and the large incidence of remittance in early adulthood. Recent studies, however, show that 30% of children with absence seizures are pharmaco-resistant and 60% are affected by severe neuropsychiatric comorbid conditions, including impairments in attention, cognition, memory and mood. In particular, attention deficits can be detected before the epilepsy diagnosis, may persist even when seizures are pharmacologically controlled and are aggravated by valproic acid monotherapy. New functional MRI-magnetoencephalography and functional MRI-EEG studies provide conclusive evidence that changes in blood oxygenation level-dependent signal amplitude and frequency in children with absence seizures can be detected in specific cortical networks at least 1 min before the start of a seizure, spike-wave discharges are not generalized at seizure onset and abnormal cortical network states remain during interictal periods. From a neurobiological perspective, recent electrical recordings and imaging of large neuronal ensembles with single-cell resolution in non-anaesthetized models show that, in contrast to the predominant opinion, cortical mechanisms, rather than an exclusively thalamic rhythmogenesis, are key in driving seizure ictogenesis and determining spike-wave frequency. Though synchronous ictal firing characterizes cortical and thalamic activity at the population level, individual cortico-thalamic and thalamocortical neurons are sparsely recruited to successive seizures and consecutive paroxysmal cycles within a seizure. New evidence strengthens previous findings on the essential role for basal ganglia networks in absence seizures, in particular the ictal increase in firing of substantia nigra GABAergic neurons. Thus, a key feature of thalamic ictogenesis is the powerful increase in the inhibition of thalamocortical neurons that originates at least from two sources, substantia nigra and thalamic reticular nucleus. This undoubtedly provides a major contribution to the ictal decrease in total firing and the ictal increase of T-type calcium channel-mediated burst firing of thalamocortical neurons, though the latter is not essential for seizure expression. Moreover, in some children and animal models with absence seizures, the ictal increase in thalamic inhibition is enhanced by the loss-of-function of the astrocytic GABA transporter GAT-1 that does not necessarily derive from a mutation in its gene. Together, these novel clinical and experimental findings bring about paradigm-shifting views of our understanding of absence seizures and demand careful choice of initial monotherapy and continuous neuropsychiatric evaluation of affected children. These issues are discussed here to focus future clinical and experimental research and help to identify novel therapeutic targets for treating both absence seizures and their comorbidities.
Topics: Adolescent; Animals; Child; Comorbidity; Humans; Seizures
PubMed: 32437558
DOI: 10.1093/brain/awaa072 -
Seizure Aug 2021First seizures are always challenging for physicians. Determining etiology, risk of recurrence, need for diagnostic electroencephalogram (EEG) or neuroimaging, balancing... (Review)
Review
OBJECTIVE
First seizures are always challenging for physicians. Determining etiology, risk of recurrence, need for diagnostic electroencephalogram (EEG) or neuroimaging, balancing starting anti-seizure medication (ASM) versus its potential adverse effects, and addressing patient and family concerns about social or emotional impact in lifestyle issues is always demanding.
METHOD
a narrative review providing information from a database search between January 1970 to November 2020 was conducted, with the following search terms: first seizure, epidemiology, treatment, neuroimaging, electroencephalogram, impact, lifestyle.
RESULTS
Incidence rates of single unprovoked seizures range from 23 to 64.1 /100000/person-years. The risk of recurrence depends on several clinical, etiological, EEG, and neuroimaging findings that should be approached on an individual basis. Initiating ASM is not generally advised, but shall be considered in individual situations. The emotional and social impact of single seizures must not be underestimated. Some interesting clues are pointing out at risks to present or prevent a first seizure.
CONCLUSION
Presentation of first seizure, diagnostic workup, treatment, and impact should be considered individually based on continuously updated knowledge of treating physicians.
Topics: Adult; Anticonvulsants; Carbamazepine; Child; Electroencephalography; Epilepsies, Partial; Epilepsy, Generalized; Humans; Recurrence; Seizures
PubMed: 33840584
DOI: 10.1016/j.seizure.2021.03.027 -
Epilepsia Apr 2010The International League Against Epilepsy (ILAE) Commission on Classification and Terminology has revised concepts, terminology, and approaches for classifying seizures...
The International League Against Epilepsy (ILAE) Commission on Classification and Terminology has revised concepts, terminology, and approaches for classifying seizures and forms of epilepsy. Generalized and focal are redefined for seizures as occurring in and rapidly engaging bilaterally distributed networks (generalized) and within networks limited to one hemisphere and either discretely localized or more widely distributed (focal). Classification of generalized seizures is simplified. No natural classification for focal seizures exists; focal seizures should be described according to their manifestations (e.g., dyscognitive, focal motor). The concepts of generalized and focal do not apply to electroclinical syndromes. Genetic, structural-metabolic, and unknown represent modified concepts to replace idiopathic, symptomatic, and cryptogenic. Not all epilepsies are recognized as electroclinical syndromes. Organization of forms of epilepsy is first by specificity: electroclinical syndromes, nonsyndromic epilepsies with structural-metabolic causes, and epilepsies of unknown cause. Further organization within these divisions can be accomplished in a flexible manner depending on purpose. Natural classes (e.g., specific underlying cause, age at onset, associated seizure type), or pragmatic groupings (e.g., epileptic encephalopathies, self-limited electroclinical syndromes) may serve as the basis for organizing knowledge about recognized forms of epilepsy and facilitate identification of new forms.
Topics: Epilepsy; Humans; International Agencies; Seizures; Syndrome; Terminology as Topic
PubMed: 20196795
DOI: 10.1111/j.1528-1167.2010.02522.x -
Epilepsia Sep 1998We propose an epileptic seizure classification based exclusively on ictal semiology. In this semiological seizure classification (SSC), seizures are classified as...
We propose an epileptic seizure classification based exclusively on ictal semiology. In this semiological seizure classification (SSC), seizures are classified as follows: a. Auras are ictal manifestations having sensory, psychosensory, and experiential symptoms. b. Autonomic seizures are seizures in which the main ictal manifestations are objectively documented autonomic alterations. c. "Dialeptic" seizures have as their main ictal manifestations an alteration of consciousness that is independent of ictal EEG manifestations. The new term "dialeptic" seizure has been coined to differentiate this concept from absence seizures (dialeptic seizures with a generalized ictal EEG) and complex partial seizures (dialeptic seizures with a focal ictal EEG). d. Motor seizures are characterized mainly by motor symptoms and are subclassified as simple or complex. Simple motor seizures are characterized by simple, unnatural movements that can be elicited by electrical stimulation of the primary and supplementary motor area (myoclonic, tonic, clonic and tonic-clonic, versive). Complex motor seizures are characterized by complex motor movements that resemble natural movements but that occur in an inappropriate setting ("automatisms"). e. Special seizures include seizures characterized by "negative" features (atonic, astatic, hypomotor, akinetic, and aphasic seizures). The SSC identifies in detail the somatotopic distribution of the ictal semiology as well as the seizure evolution. The advantages of a pure SSC, as opposed to the current classification of the International League Against Epilepsy (ILAE), which is actually a classification of electroclinical syndromes, are discussed.
Topics: Electroencephalography; Epilepsy; Humans; Seizures; Syndrome; Terminology as Topic
PubMed: 9738682
DOI: 10.1111/j.1528-1157.1998.tb01452.x -
Epileptic Disorders : International... Jun 2015To review the literature about febrile seizures and GEFS plus with special emphasis on management and outcome. Selected literature review. Febrile seizures are the most... (Review)
Review
To review the literature about febrile seizures and GEFS plus with special emphasis on management and outcome. Selected literature review. Febrile seizures are the most common convulsive event in humans, occurring in 2-6% of the population. The aetiology is complex with strong evidence for a heterogeneous genetic predisposition interacting with fever of any cause, with certain viral infections having a greater effect. A large amount of literature has established that febrile seizures have no long-term consequences on cognition or behaviour. Unfortunately, about 40% of children with a first febrile seizure will have a recurrence. The strongest predictor of recurrence is age <14-16 months at the time of the first febrile seizure. Epilepsy follows febrile seizures in ∼3% cases, with the concepts of simple and complex febrile seizures providing relatively weak prediction. Very prolonged febrile seizures may lead to mesial temporal sclerosis and temporal lobe epilepsy although the degree of risk remains uncertain. Investigations beyond establishing the cause of the provoking fever are nearly always unnecessary. Treatment is mainly reassurance and there is some evidence that parents eventually "come to grips" with the fear that their children are dying during a febrile seizure. Antipyretic medications are remarkably ineffective to prevent recurrences. Daily and intermittent prophylactic medications are ineffective or have unacceptable side effects or risks. "Rescue" benzodiazepines may prevent prolonged recurrences for selected patients with a first prolonged febrile seizure although this has not been proven. Genetic epilepsy with febrile seizures plus (GEFS+) is a complex autosomal dominant disorder usually caused by mutations in SCN1A (a voltage-gated sodium channel). One third of patients have febrile seizures only; two thirds have a variety of epilepsy syndromes, both focal and generalized. Febrile seizures may distress parents but rarely have any long-term consequences. Reassurance is the only treatment for the vast majority. Identifying patients with GEFS plus may lead to further investigations and counselling.
Topics: Child; Epilepsy, Generalized; Humans; Seizures, Febrile
PubMed: 25917466
DOI: 10.1684/epd.2015.0737 -
Seizure Oct 2018To summarize information on the history, incidence, clinical manifestation, best treatment, as well as prognosis of seizures in transplant recipients. (Review)
Review
PURPOSE
To summarize information on the history, incidence, clinical manifestation, best treatment, as well as prognosis of seizures in transplant recipients.
METHODS
In October 2017, we searched the literature on PubMed in English with the search terms: "transplantation" AND "seizure", "transplantation" AND "epilepsy", "transplantation"AND "status epilepticus", "immunosuppressant" AND "seizure", "immunosuppressant" AND "epilepsy". Publications not based on new data and original research were not included in this article.
RESULTS
Seizures including generalized seizures, focal seizures and status epilepticus are a common central nervous system complication after transplantation. The incidence of seizures varied between different kinds of transplantations. The reported incidence of seizures was 7%-27% in association with solid organ transplantations and 1.6%-15.4% with hematopoietic stem cell transplantation. Most of seizures appeared in the early post-transplantation period. Patients often had a favorable prognosis, however, in some conditions, recurrent or intractable seizures may occur.
CONCLUSIONS
The underlying pathogenesis of new-onset seizures or epilepsy in recipients of transplantation needs to be further elucidated. In addition, more information is required from prospective studies and research focusing on therapeutic strategies.
Topics: Humans; Postoperative Complications; Risk Factors; Seizures; Transplantation
PubMed: 30179843
DOI: 10.1016/j.seizure.2018.08.010 -
Seizure Dec 2020Three decades after its introduction as an adjuvant therapeutic option in the management of selective drug-resistant epilepsy cases (DRE), vagus nerve stimulation (VNS)... (Review)
Review
Three decades after its introduction as an adjuvant therapeutic option in the management of selective drug-resistant epilepsy cases (DRE), vagus nerve stimulation (VNS) retains growing interest. An implantable device was first approved for epilepsy in Europe in 1994 and in the United States (US) in 1997. Subsequent modifications improved the safety and the efficacy of the system. The most recent application of vagal neurostimulation is represented by transcutaneous devices that are claimed to have strong therapeutic potential. In this review, we sought to analyze the most meaningful available data describing the indications, safety and efficacy of the different approaches of VNS in clinical practice. Therefore, we identified studies reporting VNS efficacy and/or safety in epilepsy and its comorbidities from January 1990 to February 2020 from various databases including PubMed, Scopus, Cochrane, US government databases and VNS manufacturer published resources. In general, VNS efficacy becomes optimal around the sixth month of treatment and a 50-100 % seizure frequency reduction is achieved in approximately 45-65 % of the patients. However, some clinically relevant differences have been reported with specific factors such as epilepsy etiology or type, patient age as well as the delay of VNS therapy onset. VNS efficacy on seizure frequency has been demonstrated in both children and adults, in lesional and non-lesional cases, in focal and generalized epilepsies, on both seizures and epilepsy comorbidities. Regarding the latter, VNS can lead to an improvement of about 25-35 % in depression scores, 35 % in anxiety scores and 25 % in mood assessment scores. If non-invasive devices are undeniably safer, their efficacy is limited due to the scarcity of large cohort studies and the disparity of methodological approaches (study design and stimulation parameters). Overall, we believe that there is a progress margin for improving the safety of implantable devices and, above all, the effectiveness of the various VNS approaches.
Topics: Drug Resistant Epilepsy; Epilepsy; Europe; Humans; Seizures; Treatment Outcome; Vagus Nerve Stimulation
PubMed: 33120323
DOI: 10.1016/j.seizure.2020.09.027 -
Neurology Oct 2020To test the hypothesis that absence seizures can evolve to generalized tonic-clonic seizures, we documented electroclinical features of this novel seizure type.
OBJECTIVE
To test the hypothesis that absence seizures can evolve to generalized tonic-clonic seizures, we documented electroclinical features of this novel seizure type.
METHODS
In 4 large video-EEG databases, we identified recordings of seizures starting with impaired awareness that, without returning to baseline interictal state, evolved to generalized tonic-clonic seizures. We extracted the detailed semiologic and electrographic characteristics of these seizures, and we documented the clinical background, diagnoses, and therapeutic responses in these patients.
RESULTS
We identified 12 seizures from 12 patients. All seizures started with a period of impaired awareness and bursts of generalized spike or polyspike and slow-wave discharges, the hallmark of absence seizures. Without returning to baseline, the nonmotor (absence) phase was followed by tonic-clonic convulsions. We called this novel generalized seizure type absence-to-bilateral-tonic-clonic seizure. Most patients had idiopathic generalized epilepsies, although with a high incidence of unusual features and poor therapeutic response.
CONCLUSIONS
Absence-to-bilateral-tonic-clonic seizures are a novel generalized seizure type. Clinicians should be aware of this seizure for correctly diagnosing patients. This novel seizure type may further elucidate generalized ictogenesis.
Topics: Adolescent; Adult; Child; Electroencephalography; Female; Humans; Male; Middle Aged; Seizures; Young Adult
PubMed: 32817392
DOI: 10.1212/WNL.0000000000010470