Concepts of absence epilepsies

Berkovic, Samuel F.; Andermann, Frédérick; Andermann, Eva; Gloor, P.

doi:10.1212/wnl.37.6.993

Cited by 215 publications

(109 citation statements)

References 5 publications

(5 reference statements)

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“…The etiologic factors and relations between each syndrome are not clearly understood. Some authors postulate that IGE syndrome in adults is a new syndrome (11,12), whereas the concept of a continuum among IGE subjects is debated (13,14). In this study, we looked for etiologically related syndromic differences between the classic group of IGE and the adultonset group of IGE.…”

Section: Discussionmentioning

confidence: 99%

EEG in Adult‐onset Idiopathic Generalized Epilepsy

Yenjun

Harvey²,

Marini

et al. 2003

Epilepsia

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Summary:Purpose: It remains controversial whether adultonset idiopathic generalized epilepsy (IGE) is a distinct syndrome or a continuum among IGE syndromes. EEG is the only known biologic marker of IGE and helps differentiate many of its classic subsyndromes. In this study, we looked for the differences in the EEG findings of IGE of classic adolescent onset versus adult onset that may suggest syndromic heterogeneity.Methods: Seventy-six patients (47 adolescent-onset IGE, 29 adult-onset IGE) with a clinical and EEG diagnosis of IGE were included. We defined IGE with age at onset of 11-20 years as adolescent-onset IGE and age at onset of 20 years or after as adult-onset IGE. Patients with first-decade onset of seizures, delayed EEGs, and no EEG available for review were excluded. The first EEG was performed within 24 h of the seizure, and if negative, a sleep-deprived EEG was done. All EEGs were reviewed in detail with respect to the background activity and the generalized spike-wave (GSW) characteristic.Results: EEGs (87; 56 adolescent-onset IGE, 31 adult-onset IGE) were systematically reviewed. Background was normal in all patients. The morphology, amplitude, duration, frequency, occurrence, or activation of the GSW pattern did not differ between these two groups.Conclusions: No differences of EEG features were found between the classic adolescent-onset and the adult-onset IGE. This supports the hypothesis that they share common biologic determinants and exist along a life-long age spectrum of classic IGE.

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Section: Discussionmentioning

confidence: 99%

EEG in Adult‐onset Idiopathic Generalized Epilepsy

Yenjun

Harvey²,

Marini

et al. 2003

Epilepsia

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“…One of the dogmas for the classification of IGE is that there should be no brain lesions, either anatomic or biochemical (1,15, [29][30][31][32][33]. This dogma has been challenged, pri- marily by Meencke et al (34,35) who detected dysgenetic cortical lesions in 88% of the brains of patients who had such epilepsies, whereas such lesions had been reported to occur in only 4% of brains of nonepileptic subjects (36).…”

Section: Discussionmentioning

confidence: 99%

Consistent EEG Focalities Detected in Subjects with Primary Generalized Epilepsies Monitored for Two Decades

Lombroso

1997

Epilepsia

135

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Summary:Purpose: To describe the evolution of interictal findings in serial EEGs from patients with primary generalized epilepsy.Methods: A cohort of 89 subjects with various primary generalized epilepsies were reviewed. Thirty-one did not meet a priori criteria. Of the 58 patients analyzed, 12 had only absence seizures, 28 had absence seizures followed by one or more generalized tonic-clonic seizures, 9 had generalized tonicclonic seizures followed by absence and/or myoclonic seizures, and 9 had juvenile myoclonic epilepsy. Patients were followed for a mean of 16 years. An average of 39 EEGs were obtained on each patient.Results: Thirty-two patients (56%) had focal features present in up to 65% of the EEGs in each of the patients. Accepted focalities were only those that were consistent in lateralization, location and, often, morphology across the span of the study. Focal findings were most often temporal or frontal.Conclusions: Patients with typical primary generalized epilepsies show a high incidence of focal EEG features that cannot be explainea on the basis of structural lesions, coincidental factors, or to artifacts of the selection criteria. Although the data do not allow a definitive explanation, possible mechanisms include associated focal cortical pathology such as microdysgenesis, and development over time of localized, self-sustaining hyperexcitability in low-threshold cortical structures subjected to repeated generalized spike-wave activity. Either hypothesis implies the participation and interaction of genetic, ontogenic, and environmental factors. Key Words: Focal electroencephalograms-Idiopathic generalized epilepsy-Longterm follow-up.The classification of epilepsies and epileptic syndromes proposed in 1989 (1) defines the idiopathic (primary) generalized epilepsies (ICE) as those whose seizure phenotypes indicate the involvement of -both hemispheres from the onset, both clinically and electrographically. By definition, the IGE show no evidence of structural brain lesions, in contrast to the secondarily generalized group of epilepsies, and no known or suspected etiology other than the contributions of polygenic factors. Their EEG expression (ictally or interictally) consists of initially generalized, bilaterally symmetrical discharges, whereas the background patterns are normal for age.Despite many efforts made in the past half century by both clinicians and neuroscientists, the pathophysiology of IGE remains unsettled. Among still-controversial issues are the predicated complete lack of structural brain lesions and the precise role played by the cortex.A long-term follow-up in a population of subjects with ICE shows that their EEGs often contain focal abnormalities that are persistent and consistent in location-an

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“…Estas manifestações estão associadas a complexos espícula-onda lenta generalizados no eletroencefalograma (EEG) 3,4 . Em alguns pacientes, o diagnóstico diferencial entre crises parciais complexas e crises de ausências pode ser difícil, levando a um diagnóstico inadequado da síndrome epiléptica 3,[5][6][7] . O objetivo deste estudo foi avaliar os fatores mais frequentemente associados a dificuldades no diagnóstico diferencial entre crises tipo ausências e mioclonias e crises parciais e assim tentar indicar elementos diagnósticos na rotina que possam ser úteis para o neurologista geral e epileptologista em fase de treinamento.…”

Section: Dr Fernando Cendes -Departamento De Neurologia Faculdade Dunclassified

Epilepsias generalizadas idiopáticas diagnosticadas incorretamente como epilepsias parciais

Mory

Guerreiro

et al. 2002

Arq. Neuro-Psiquiatr.

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RESUMO -A epilepsia generalizada idiopática (EGI) frequentemente não é diagnosticada corretamente em adultos, com sérias consequências para os pacientes. O objetivo deste estudo foi avaliar os fatores mais frequentemente associados a dificuldades no diagnóstico diferencial entre epilepsias parciais e generalizadas em adultos. Avaliamos 41 pacientes com diagnostico de crises parciais complexas com elementos de anamnese e EEG indicando um possível diagnóstico diferencial. Foi possível a mudança do diagnóstico de epilepsia parcial para EGI em 25 pacientes: 22 (88%) com EMJ; um com ausência juvenil, um com síndrome de ausências com mioclonias periorais e um com ausência com mioclonias palpebrais. Mioclonias, uma das características da EMJ e outras formas de EGI, geralmente não eram espontaneamente relatadas pelos pacientes. Abalos mioclônicos unilaterais eram confundidos com crises parciais motoras. Ausências breves e pouco frequentes e anormalidades focais no EEG contribuíram para o não reconhecimento de EGI. Todos os 25 pacientes apresentavam crises sem controle adequado antes da revisão diagnóstica. Após o diagnóstico correto e mudança para monoterapia com acido valpróico ou valproato de sódio, 19 (76%) ficaram livre de crises e seis (24%) dos 25 pacientes apresentaram melhora significativa. A associação de lamotrigina em três destes pacientes propiciou redução significativa da frequência de crises. Em conclusão, anamnese detalhada e questionamento direcionado para determinar a presença de mioclonias e crises tipo ausência e a sua interpretação no contexto clínico são fundamentais para o diagnóstico correto das EGI em adultos. PALAVRAS-CHAVE: epilepsia, diagnostico, tratamento, EEG. Idiopathic generalized epilepsies misdiagnosed as partial epilepsiesABSTRACT -Idiopathic generalized epilepsy (IGE) is often not recognized with serious consequences on the sufferers. We examined factors contributing to the missed diagnosis of IGE in 41 adults attending our epilepsy clinic with diagnosis of partial epilepsy who had semiology or EEG findings suggesting a possible differential diagnosis. After careful re-evaluation, the diagnosis of IGE was established in 25 patients: 22 (88%) with JME, one with juvenile absence, one with perioral myoclonia with absences, one with eyelid myoclonia with typical absences. Myoclonic jerks, the hallmark of the JME and other IGE, were not usually reported by patients or misdiagnosed as focal motor seizures. Brief and infrequent absence seizures and focal EEG abnormalities were other factors contributing to not recognizing JME. All 25 patients did not achieve seizure control before re-evaluation of diagnosis. After appropriate diagnosis of IGE and change of AED to valproate or valproic acid, 19 (76%) became seizure free and six (24%) had a significant improvement on seizure control. Association with lamotrigine provided further improvement in three of these patients. An appropriate questioning to identify myoclonic and absence seizures and a proper interpretation in the context of whole clini...

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Concepts of absence epilepsies

Cited by 215 publications

References 5 publications

EEG in Adult‐onset Idiopathic Generalized Epilepsy

EEG in Adult‐onset Idiopathic Generalized Epilepsy

Consistent EEG Focalities Detected in Subjects with Primary Generalized Epilepsies Monitored for Two Decades

Epilepsias generalizadas idiopáticas diagnosticadas incorretamente como epilepsias parciais

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