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PubMed2003

Syndromic classification of patients with typical absence seizures.

The aim of this study is to compare ILAE classification (1989) and Panayiotopoulos' criteria (1997) for absence epilepsies. We studied 455 typical absences (ILAE, 1981) by video-EEG in 43 patients with normal neurological and neuroradiological examinations and interictal EEG with spike-wave complexes higher than 2.5Hz. Syndromic diagnosis was possible in 60.5% and 67.4% of the patients using ILAE classification and Panayiotopoulos' proposal, respectively. According to ILAE criteria 19 patients had childhood absence epilepsy (CAE), five juvenile absence epilepsy (JAE), one juvenile myoclonic epilepsy (JME) and one epilepsy with specific modes of seizure precipitation. According to Panayiotopoulos' proposal, 10 had CAE, 14 JAE, one JME, three myoclonic absence epilepsy and one eyelid myoclonia with absences. We conclude that Panayiotopoulos' criteria and ILAE classification for absence epilepsies, which did not allow for the classification of 32.6% and 39.5% of cases, respectively, were still insufficient to classify all patients under specific diagnosis.

Adolescent↗
PubMed1995

The phenotypic spectrum related to the human epilepsy susceptibility gene "EJM1".

Linkage studies of families ascertained through patients with juvenile myoclonic epilepsy (JME) suggest that an HLA-linked susceptibility gene on chromosome 6, designated "EJM1," predisposes to a group of idiopathic generalized epilepsies (IGEs) comprising JME, juvenile absence epilepsy (JAE), childhood absence epilepsies (CAE), and epilepsies with generalized tonic-clonic seizures (GTCS). To explore the EJM1-related phenotypic spectrum, we conducted linkage studies with HLA-DQ alpha restriction fragment length polymorphisms in 44 families ascertained through patients with CAE or JAE. Our results for the entire group of families provide evidence against a major susceptibility locus for idiopathic absence epilepsies and broader spectra of IGEs in the HLA region. Lod scores less than -2 were obtained for a region from 10 cM up to 23 cM on either side of the HLA-DQ alpha locus, depending on the assumed trait model. Suggestive evidence for linkage was found only for a subgroup of families with JME patients assuming an autosomal dominant mode of inheritance with 70% penetrance. A maximum lod score was obtained when family members with JME, JAE, CAE, and idiopathic GTCS were included into the affection status. Our results demonstrate that (1) the genetic susceptibility to idiopathic absence epilepsies and broader spectra of IGEs is heterogeneous, (2) the gene effect of EJM1 depends on the familial genetic background, and (3) EJM1 confers genetic susceptibility to idiopathic absence epilepsies and broader spectra of IGEs in the presence of family members with JME.

Disease Susceptibility↗
PubMedDate not supplied

[The neurochemical bases of absence-type epilepsy].

The author attempts to introduce several of the present data concerning the neurochemical basis of one of the most enigmatic neurological disturbances, the so-called "petit mal" epilepsy. The present material is based on some of the most recent studies of neurochemistry, and considerations are also made concerning the experimental modelling of "petit mal" epilepsy.

Animals↗
PubMed2002

Idiopathic generalised epilepsies with 3 Hz and faster spike wave discharges: a population-based study with evaluation and long-term follow-up in 71 patients.

For several years we have been following patients with intractable, childhood-onset idiopathic generalised epilepsies with > or = 3 Hz spike-wave discharges. Our need to find explanations for their intractability was the starting point for this study. We were interested in identifying characteristics, which would predict intractability; evaluating how these patients were treated and whether polytherapy was useful. We identified patients with > or = 3 Hz spike-wave discharges by reviewing EEG reports recorded between 1983 and 1992. Data were collected from medical records and through personal interviews. We identified 82 patients with tentative idiopathic generalised epilepsy. Eleven were excluded. Thirty-eight patients had childhood absence epilepsy, 18 had juvenile absence epilepsy, 13 had juvenile myoclonic epilepsy and two had eyelid myoclonia with absences: 89.5, 78, 38 and 0% of the patients in each group, respectively, had been seizure free for more than 2 years. Twenty percent of the patients had intractable seizures. All intractable patients with juvenile absence epilepsy had rhythmic, random eyelid blinking and generalised tonic-clonic seizures. A history of more than ten generalised tonic-clonic seizures was associated with intractability in juvenile myoclonic patients. Monotherapy with ethosuximide or valproate resulted in seizure control in 65% of patients. Seventeen patients (24%) were treated with polytherapy, six achieved remission. These six patients had childhood absence epilepsy and juvenile absence epilepsy. Positive outcome was found in childhood absence epilepsy and juvenile absence epilepsy. Intractable seizures were more frequent among patients with juvenile myoclonic epilepsy. None of them benefited from polytherapy with conventional anti-epileptic drugs.

Adolescent↗
PubMed1998

Quantitative MRI in patients with idiopathic generalized epilepsy. Evidence of widespread cerebral structural changes.

In patients with idiopathic generalized epilepsy (IGE), visual inspection of routine MRI is normal. However, pathological studies have shown microdysgenesis in grey and white matter in a large percentage of autopsies from cases of IGE. Recently, widespread structural changes not evident on visual inspection of high resolution MRI have been shown using quantitative MRI in patients with apparently focal cerebral dysgenesis. We sought to determine whether similar quantitative changes might be present in patients with IGE, reflecting possible underlying structural abnormalities. Twenty patients with juvenile myoclonic epilepsy, 10 patients each with childhood absence epilepsy and juvenile absence epilepsy, five patients with tonic-clonic seizures on awakening and 30 control subjects had T1-weighted volume acquisition MRI scans on a 1.5T GE scanner. The cerebral hemispheres were segmented semi-automatically, allowing the comparison of normalized cortical and subcortical matter volumes between groups, and investigation of the regional distribution of cortical and subcortical matter in individual subjects. Patients with IGE had significantly larger cortical grey matter volumes than control subjects. Significant abnormalities of the regional distribution of cerebral grey and subcortical matter were found in eight out of 20 patients with juvenile myoclonic epilepsy, one out of 10 patients with childhood absence epilepsy, four out of 10 patients with juvenile absence epilepsy and two out of five patients with tonic-clonic seizures on awakening, but in none of the 30 control subjects. Using MRI-segmentation, we identified widespread cerebral structural changes in patients with various IGE syndromes. Quantitative MRI supports the existence of structural abnormalities in patients with IGE.

Adolescent↗
PubMed1993

Eyelid myoclonia with typical absences: an epilepsy syndrome.

Five unrelated patients are described with the clinical and electrical features of eyelid myoclonia with absences (EMA). In this syndrome brief, typical absences occur with rapid eyelid myoclonia associated with retropulsive movements of the eyeballs and occasionally of the head. The seizures are of shorter duration than in childhood absence epilepsy, and are accompanied by less profound impairment of consciousness. The electroencephalogram demonstrates high amplitude discharges consisting of spikes, multiple spikes and slow waves at a fluctuating frequency of 3-5 Hz and following eye closure, which disappear in darkness. Photosensitivity is also seen. Onset is in early childhood and EMA appears to persist into adult life. Treatment is sodium valproate in combination with either ethosuximide or a benzodiazepine. On the basis of the clinical features, EEG findings, and the response to treatment and prognosis, it is suggested that EMA be classified as a specific epilepsy syndrome.

Adolescent↗
PubMed1998

Local cerebral glucose utilization in adult and immature GAERS.

In the present study, we compared the basal local cerebral metabolic rates for glucose (LCMRglcs) both in Wistar rats with genetic absence epilepsy (GAERS: genetic absence epilepsy rats from Strasbourg) and in control non epileptic (NE) rats selected in our breeding colony. LCMRglc was measured both in immature rats at postnatal day 21 (P21) at which age no spontaneous spike-and-wave discharges can be recorded in GAERS and at the adult age (6 months) when GAERS fully express thalamo-cortical spike-and-wave discharges recorded on the EEG. LCMRglcs were measured in 24 structures by the quantitative [14C]2-deoxyglucose autoradiographic technique. In adults GAERS, LCMRglc underwent a widespread increase recorded in all brain structures except in mediodorsal and ventromedian thalamus, and in the nucleus accumbens. These metabolic increases ranged from 17 to 50% over control levels in adult NE rats. In P21 GAERS, LCMRglc was similar to that of P21 NE rats in 16 areas. It increased over control levels of NE rats in two groups of structures. Metabolic increases were recorded in four limbic structures (entorhinal and piriform cortices, hippocampus and basolateral amygdala) where no spike-and-wave discharges were recorded in adult GAERS. Increases in LCMRglcs were also located in the substantia nigra pars reticulata, superior colliculus and globus pallidus which are structures involved in the control of seizure activity. In conclusion, our data suggest that the consequences of the genetic mutation(s) underlying the cellular and molecular events responsible for the expression of spike-and-wave discharges in adult GAERS is (are) able to increase metabolic activity in both limbic structures and the nigral inhibitory system before the occurrence of spike-and-wave discharges.

Aging↗
PubMed1990

Paradoxical role of GABA in a chronic model of petit mal (absence)-like epilepsy in the rat.

Neonatal Long-Evans hooded rats were treated with AY-9944, a cholesterol biosynthesis inhibitor, every 6 days for 7 weeks to induce a permanent absence-like epileptic condition. AY-9944-treated rats averaged 50 +/- 15 generalized non-motor seizures per hour of 2-15 s duration as monitored by electrocorticography. Clinically effective anti-absence drugs were observed to reduce seizure occurrence in a dose-dependent manner. Paradoxically, GABA agonists increased seizure occurrence while GABA antagonists decreased seizure occurrence. Evaluation of the benzodiazepines, diazepam and clonazepam, in this model revealed inhibition of seizure activity by GABA-independent mechanisms. Valproic acid produced a biphasic effect suggesting a GABA-independent, antiabsence action at low doses and GABAergic augmentation of seizure occurrence at higher doses. The results of this study support the hypothesis that increased GABAergic stimulation may induce inhibitory seizures in absence epilepsy.

Animals↗
PubMed2001

New-onset absence status epilepsy presenting as altered mental status in a pediatric patient.

Absence status epilepsy (ASE) is an uncommon seizure disorder in children. The primary presentation of new-onset ASE in a pediatric patient is an unusual cause of altered mental status in the emergency department. We describe a previously healthy 8-year-old child who presented with an acutely altered mental state. The patient was awake but confused, with a fluctuating level of alertness and an inability to perform simple routine tasks. The results of general physical and neurologic examination, with the exception of mental status, were normal. Head computed tomography and laboratory test results were normal. Electroencephalographic testing revealed seizure activity consistent with ASE. Administration of intravenous diazepam caused cessation of seizure activity and a return to the patient's baseline mental function. Although rare, ASE should be considered in the differential diagnosis of altered mental status in children.

Anticonvulsants↗
PubMedDate not supplied

Interictal aggression in epilepsy: the Buss-Durkee Hostility Inventory.

Adult patients with left, right, or bilateral temporal lobe epilepsy or absence epilepsy, and normal controls completed the Buss-Durkee Hostility Inventory (BDHI), a standardized questionnaire of aggressive tendencies. Patients with left temporal lobe seizure foci scores higher on the Suspicion scale than did other patients or controls (p < 0.05). Factor analysis scale scores identified three factors: hostile feelings, covert aggression, and overt aggression. The groups differed on their pattern of factor scores (p < 0.01): patients with left temporal lobe epilepsy scored higher than other groups on hostile feelings, normal controls scored higher on Covert aggression, and bitemporal patients scores higher on Overt aggression. Patients with absence seizures did not differ from controls. Lateralization of the seizure focus in patients with temporal lobe epilepsy may alter expression of aggressive behavior.

Adult↗
PubMed1986

Petit mal epilepsy: a review and integration of recent information.

Petit mal (absence) epilepsy remains one of the most enigmatic of neurological disorders, and there is no widely accepted theory of its etiology. This review covers some of the current issues concerned with the disorder, including treatment and prognosis, neurochemical research, behavioral and psychophysiological effects of wave-spiked discharges, and EEG studies of seizure control. With respect to treatment, although effective drug therapy (valproic acid, ethosuximide) exists for the "pure" form of absence epilepsy, other forms, in which there is an admixture of grand mal seizures, are less amenable to pharmacotherapy. Moreover, the frequency of fatal hepatic toxicity following valproic acid therapy has been estimated at 1 in 20,000. With respect to prognosis, follow-up studies indicate that many patients do not outgrow the disorder but continue to suffer absence seizures well into adulthood. In recent years, there has been considerable research on the neurochemical basis of absence epilepsy. Current theories, including those that implicate gamma-aminobutyric acid, catecholamines, and "endogenous" epileptogens, are summarized; and requirements for an experimentally induced animal model of absence epilepsy are discussed. The majority of behavioral studies of the disorder have concerned the effects of petit mal-type discharges on sensory and cognitive processes. Some of these studies are reviewed; and recent work bearing on these issues, involving event-related brain potentials, is presented. Our review concludes with a discussion of research aimed at the development of electrophysiologically based approaches to the reduction of seizure frequency in patients with absence epilepsy.

Adolescent↗
PubMed2005

Typical absence seizures triggered by photosensitivity.

PURPOSE: To describe the characteristics of patients with typical absence seizures (TASs), consistently triggered by photosensitivity. METHODS: Consecutive patients having TAS induced by intermittent photic stimulation were included in the study. All clinical parameters, EEG, and video-EEG data were assessed during the long-term follow-up. Statistical analyses were performed with SPSS 10.0 software. RESULTS: Nine female and two male patients with a mean age at onset of 14 +/- 5.9 years (range, 7-27 years) and with a mean follow-up of 9 +/- 7.56 years had photosensitive TASs. They constituted 7.64% of absence epilepsies and 0.4% of all patients seen in our tertiary center. The seizures were usually subtle and had a reported frequency of 1 to 9 times daily. Seven patients were clinically photosensitive and reported that some of their TASs were induced by photic stimuli in daily life. All patients also had spontaneous TASs, and four of them had generalized tonic-clonic seizures. EEG results did not show any distinctive features when compared with those of other cases with TASs. Remission could not be achieved in five patients with antiepileptic drug treatments, and we always observed relapses after drug discontinuation or dose reduction in the remaining six cases in remission. Spontaneous remission did not occur even in the five patients older than 30 years. CONCLUSIONS: TASs triggered by photosensitivity are a rare and heterogeneous clinical condition with a marked female preponderance. It is notable that TASs do not remit in these cases.

Adolescent↗
PubMed2001

General strategy for hierarchical decomposition of multivariate time series: implications for temporal lobe seizures.

We describe a novel method for the analysis of multivariate time series that exploits the dynamic relationships among the multiple signals. The approach resolves the multivariate time series into hierarchically dependent underlying sources, each driven by noise input and influencing subordinate sources in the hierarchy. Implementation of this hierarchical decomposition (HD) combines principal components analysis (PCA), autoregressive modeling, and a novel search strategy among orthogonal rotations. For model systems conforming to this hierarchical structure, HD accurately extracts the underlying sources, whereas PCA or independent components analysis does not. The interdependencies of cortical, subcortical, and brainstem networks suggest application of HD to multivariate measures of brain activity. We show first that HD indeed resolves temporal lobe ictal electrocorticographic data into nearly hierarchical form. A previous analysis of these data identified characteristic nonlinearities in the PCA-derived temporal components that resembled those seen in absence (petit mal) seizure electroencephalographic traces. However, the components containing these characteristic nonlinearities accounted for only a small fraction of the power. Analysis of these data with HD reveals furthermore that components containing characteristic nonlinearities, though small, can be at the origin of the hierarchy. This finding supports the link between temporal lobe and absence epilepsy.

Algorithms↗
PubMed2006

A novel GABRG2 mutation associated with febrile seizures.

Mutations in the gene encoding the gamma2 subunit of the gamma-aminobutyric acid type A receptor (GABRG2) have been reported to cause childhood absence epilepsy (CAE), febrile seizures (FS), and generalized epilepsy with FS plus (GEFS+). The authors analyzed GABRG2 in 47 unrelated patients with CAE, FS, and GEFS+ and identified a novel mutation that cosegregated with FS. Electrophysiologic studies demonstrated altered current desensitization and reduced benzodiazepine enhancement in mutant receptors.

Belgium↗
PubMed2005

Identification of two further splice variants of GABABR1 characterizes the conserved micro-exon 4 as a hot spot for regulated splicing in the rat brain.

Inhibitory neurotransmission in the mammalian brain is principally mediated by gamma-aminobutyric acid (GABA) acting through different subtypes of cell membrane GABA receptor (GABAR). The expression of one GABAR gene, GABABR1, is distinguished by the expression of multiple splice variants that encode different isoforms of the receptor. In the present study, we have identified two novel GABABR1 variants, GABABR1h (R1h) and GABABR1i (R1i), which appear to arise from alternative splicing of the GABABR1 gene. The expression of R1h and R1i is differentially regulated in brain and peripheral tissues, but expression is not altered in the brain of a genetic model of absence epilepsy (GAERS rat [genetic absence epilepsy rat from Strasbourg]). Both the R1h and R1i variants exhibit a novel 80-bp insert downstream of exon 4 that is flanked by consensus splice sites, and both encode C-terminal-truncated proteins. The new insight into the family of GABABR1 variants gained from this study identifies exon 4 as a preferred locus, or hot spot for regulated splicing in the GABABR1 gene. This finding correlates with the micro-exonic nature of exon 4 (21 bp). Bioinformatic analysis of micro-exon 4 and its flanking pre-mRNA sequences has revealed multiple, potentially competitive, exonic splicing enhancers that provide a mechanistic basis for the preponderance of alternative splicing events at this locus. Conservation of GABABR1 micro-exon 4 across species suggests a conserved functional role, facilitating either N-terminal protein production or post-transcriptional gene regulation through regulated splicing coupled to transcript decay.

Alternative Splicing↗
PubMed2001

Cognitive function in adolescents and young adults in complete remission from benign childhood epilepsy with centro-temporal spikes.

Benign childhood epilepsy with centrotemporal spikes (BECTS) is a frequent, benign childhood epilepsy with a good prognosis. However, neuropsychological deficits have been reported during its active phase. In this study, we evaluate the long-term neuropsychological consequences of this reputedly benign epilepsy, particularly the relation between paroxysmal abnormalities and cerebral language lateralization. The neuropsychological outcomes concerning both overall cognitive and lateral hemispheric functions were studied in twenty-three adolescents and young adults in total recovery from BECTS, in thirty-three controls without any significant past neurological history and in ten adolescents and young adults with complete resolution of generalized idiopathic epilepsy (childhood absence epilepsy or CAE). Language lateralization was evaluated using classical neuropsychological procedures (dichotic listening tasks, dual-task procedure). No difference was seen in the three populations with respect to overall cognitive function: memory, language and the executive functions. Although the Performance IQ was lower in patients in remission from CAE, the results were within normal limits. However, qualitative analysis of the dual-task procedure suggested a different organizational pattern for cerebral language in adolescents and young adults in remission from BECTS as compared to controls and patients in remission from CAE. The different organization in cerebral pattern in BECTS patients appeared to be related to the initial epileptic focus as determined by the EEG and/or the sleep-recording. We discuss the relationship between the presence of paroxysmal anomalies in childhood and subtle functional lateralized hemispheric abnormalities in adulthood.

Adolescent↗
PubMed2000

Primary Generalized Epilepsies.

For pure childhood absence epilepsy (CAE), ethosuximide (ESM) remains the drug of first choice. Although valproic acid (VPA) is of equal efficacy, it is more toxic, and is reserved for those patients with accompanying convulsions. Lamotrigine (LTG) is effective as both add-on and monotherapy for CAE. If any of these three drugs fails, one of the other two can be used as monotherapy. Rarely, when ESM, VPA, or LTG does not effectively control CAE, phenytoin (PHT), primidone (PRM), and phenobarbital (PB) may be partially effective, although carbamazepine (CBZ) may worsen absence seizures. Experience is limited with the newer AEDs. Tiagabine (TGB) may induce absence status epilepticus in PGE. Oxcarbazepine (OXC) and vigabatrin (VGB) may worsen absence seizures. Felbamate (FBM) is probably effective, but is potentially fatal. Lifelong therapy is not anticipated. For juvenile absence epilepsy (JAE), VPA is the drug of first choice. LTG is also of proven efficacy. The risks of VPA-induced teratogenicity (possibly lessened by the concurrent use of folic acid) and weight gain are potentially unacceptable in young women of childbearing age. Not enough data exists on the safety of LTG in pregnancy. A combination of VPA and LTG can be used if either drug alone is unsuccessful. For juvenile myoclonic epilepsy (JME), VPA is the traditional drug of first choice in most patients. As in JAE, side effects may make VPA an unacceptable choice in many patients, especially young women. In clinical practice, TPM is being increasingly used as monotherapy for JME. Many patients appreciate the accompanying weight loss seen with TPM, but it has potentially troubling side effects, has not been well studied as monotherapy for JME, and its safety in pregnancy has yet to be confirmed. PHT and CBZ may worsen myoclonus when used alone, but they may have a role as add-on treatment to VPA, LTG, or TPM, especially when generalized tonic-clonic seizures (GTCSs) are not controlled. PB and PRM may also be useful as add-on treatment, but often have unacceptable side effects. Clonazepam may be useful as adjunctive treatment for resistant myoclonic jerks. OXC and VGB both worsen myoclonic seizures. GBP is not useful in JME and can make seizures worse. The efficacy of FBM and TGB in JME is largely unknown. Lifelong AED therapy is necessary. In epilepsy with generalized tonic-clonic seizure (GTCS) on awakening (EGA), VPA is the drug of choice, especially if other seizure types (absence and myoclonic) are present. If only GTCSs are present, then PB, PHT, and CBZ may be as effective as VPA; however, the use of PHT and CBZ may "unearth" other seizure types (absence and myoclonic) in those patients with EGA, although PB is poorly tolerated. As for JME, LTG, and TPM may both be effective monotherapy for EGA, although the use of other AEDs in EGA has not been well studied. Lifelong AED treatment is necessary.

Journal Article↗