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At least 217 records · Page 12Linked to original sources
PubMed1996

Accidental injury is a serious risk in children with typical absence epilepsy.

OBJECTIVES: To determine if young adults with a history of typical absence epilepsy (AE) in childhood have a greater risk of accidental injury than controls with juvenile rheumatoid arthritis (JRA). To assess the nature and severity of these injuries. METHODS: All patients with AE or JRA diagnosed between 1977 and 1985, who were 18 years or older at the onset of the study, were identified from review of pediatric electroencephalographic records for the province of Nova Scotia (AE) or review of the medical records database at the only tertiary care pediatric center for the province (JRA). Fifty-nine (86%) of 69 patients with AE and 61 (80%) of 76 patients with JRA participated in an interview in 1994 or 1995, assessing nature, severity, and treatment of prior accidental injuries. Patients with AE were further questioned about injuries sustained during an absence seizure. RESULTS: Sixteen (27%) of 59 patients with AE reported accidental injury during an absence seizure, with risk of injury being 9% per person-year of AE. Most injuries (81%) occurred during anti-epileptic drug therapy. Although the majority of injuries did not require treatment, 2 (13%) of 16 patients required minor treatment and 2 (13%) of 16 were admitted to hospital. The risk of accidental injury resulting from an absence seizure in person-years at risk was highest in juvenile myoclonic epilepsy (45%), moderate in juvenile AE (14%), and lowest in childhood AE (3%). Patients with AE had a greater number of overall accidental injuries than those with JRA (P<.04), but these differences were particularly marked for bicycle (P<.003) and car accidents (P<.05) and for mild head injuries (P=.05). CONCLUSIONS: Accidental injury is common in AE and usually occurs after anti-epileptic drug treatment is started. Injury prevention counseling is indicated both at diagnosis and follow-up. Bicycle accidents pose a special risk and helmet use should be mandatory.

Accidental Falls↗
PubMed1994

Effects of mu and delta opioid receptor agonists and antagonists on absence epilepsy in WAG/Rij rats.

The effects of various types of opioid receptor agonists and antagonists were determined in a genetic rat model for generalized absence epilepsy. Rats of the WAG/Rij strain spontaneously showed several hundred spike-wave discharges per day. Intracerebroventricular (i.c.v.) injections of the selective mu agonist DAMGO (0.2, 0.7 microgram) resulted in a dose-related increase in the number of spike-wave discharges, while the selective delta agonist DPDPE (20, 60 micrograms) was without effect. DAMGO reduced the duration of automatic behavior, enhanced the immobile behavior (after the low dose) and had no effect on exploratory behavior. On the other hand, DPDPE significantly enhanced the total time spent on exploration, but did not influence other behavioral parameters. There was no correlation between the ability to the drug to modulate the epileptic activity and behavioral changes. The nonselective antagonist naloxone, administered either i.p. (0.4, 2.0, 10 mg/kg) or i.c.v. (10, 50 micrograms), increased the number of spike-wave discharges in a dose-dependent way. The specific delta receptor antagonist naltrindole (0.3, 1 mg/kg) was without effect, as was the irreversible mu receptor antagonist beta-funaltrexamine (beta-FNA). Pretreatment with beta-FNA diminished the action of DAMGO. These results clearly indicate that activation of the mu opioid receptor increases the number of spike-wave discharges, and that modulation of delta receptors is not effective. On the other hand, the naloxone-induced enhancement of spike-wave discharges, suggests a tonic control of the epileptic activity by another opioid system. These results point to an important role of the mu-, but not delta-, receptor in facilitation of the epileptic activity in WAG/Rij rats.

Analysis of Variance↗
PubMed2002

[Case-control study and transmission/disequilibrium test of childhood absence epilepsy].

OBJECTIVE: To investigate whether or not the gamma-aminobutyric acid (GABA) receptor subtype A genes GABRA5 and GABRB3 are associated with childhood absence epilepsy (CAE). METHODS: Two microsatellite DNA, GABRA5 and GABRB3, adjoining to chromosome 15q11.2-q12 were used as genetic markers. Both case-control study and transmission/disequilibrium test (TDT) as well as fluorescence-based semi-automated genotyping technique were used in 90 trios with CAE and 100 controls to conduct association analysis. RESULTS: The allele frequencies of the 2 microsatellite DNA in Chinese normal population are in good agreement with Hardy-Weinberg equilibrium. The polymorphism information content of microsatellite DNA GABRA5 and GABRB3, are 0.80 and 0.66 respectively. The allele 2 frequency of microsatellite DNA GABRA5 and the allele 5 frequency of microsatellite DNA GABRB3 are significantly higher in CAE patients than those in normal controls(P<0.001). CONCLUSION: Both microsatellite DNA GABRA5 and GABRB3 are good genetic markers. The gamma-aminobutyric acid receptor subtype A genes GABRA5 and GABRB3 may be directly involved either in the etiology of CAE or in linkage disequilibrium with disease-predisposing sites.

Adolescent↗
PubMed2003

Childhood absence epilepsy and febrile seizures: a family with a GABA(A) receptor mutation.

Although several genes for idiopathic epilepsies from families with simple Mendelian inheritance have been found, genes for the common idiopathic generalized epilepsies, where inheritance is complex, presently are elusive. We studied a large family with epilepsy where the two main phenotypes were childhood absence epilepsy (CAE) and febrile seizures (FS), which offered a special opportunity to identify epilepsy genes. A total of 35 family members had seizures over four generations. The phenotypes comprised typical CAE (eight individuals); FS alone (15), febrile seizures plus (FS(+)) (three); myoclonic astatic epilepsy (two); generalized epilepsy with tonic-clonic seizures alone (one); partial epilepsy (one); and unclassified epilepsy despite evaluation (two). In three remaining individuals, no information was available. FS were inherited in an autosomal dominant fashion with 75% penetrance. The inheritance of CAE in this family was not simple Mendelian, but suggestive of complex inheritance with the involvement of at least two genes. A GABA(A) receptor gamma2 subunit gene mutation on chromosome 5 segregated with FS, FS(+) and CAE, and also occurred in individuals with the other phenotypes. The clinical and molecular data suggest that the GABA(A) receptor subunit mutation alone can account for the FS phenotype. An interaction of this gene with another gene or genes is required for the CAE phenotype in this family. Linkage analysis for a putative second gene contributing to the CAE phenotype suggested possible loci on chromosomes 10, 13, 14 and 15. Examination of these loci in other absence pedigrees is warranted.

Adult↗
PubMed2005

[A family with exercise-induced paroxysmal dystonia and childhood absence epilepsy].

INTRODUCTION: The boundary between epilepsy and paroxysmal dyskinesia appears to be less easy to delineate than previously believed. Reports of families showing both phenomena suggest a shared pathophysiology. PATIENTS AND METHOD: A new family with autosomal dominant exercise-induced paroxysmal dystonia is reported. RESULTS: Two family members also had childhood absence epilepsy, and one of them suffered from acute transient hemiplegia at age 10. CONCLUSION: The association of epilepsy and paroxysmal dyskinesia has been rarely reported in the literature, and several loci have been identified. Absence epilepsy and exercise-induced paroxysmal dystonia appear to be very uncommon, although some reports mentioned the association in sporadic and familial cases. The involvement of ion channel genes in several transient neurological disorders supports the hypothesis of a common pathophysiological process underlying both the childhood absence seizure and the later paroxysmal dystonia.

Adult↗
PubMed2002

Early-onset absence epilepsy and paroxysmal dyskinesia.

PURPOSE: To report on the association of childhood absence epilepsy and paroxysmal dyskinesia (PD). METHODS: We describe six patients aged 6 to 27 years (mean, 14 years) who were identified in five centers participating in a European study group. Patients had been followed up clinically from the first symptoms and had been studied with video-EEG recordings of absence seizures, videotaping of dyskinetic attacks, and brain magnetic resonance imaging (MRI). RESULTS: Four patients were sporadic, and two were siblings. Age at onset of absence seizures was unusually early (range, 3 months to 3 years 6 months; mean, 16 months), with four children having their first episodes within the first year of life, and the remaining two by age 3 years 6 months. Resistance to multiple appropriate drugs was seen in five children, in four of whom absences improved remarkably when ethosuximide was added. Absences remitted between age 8 and 13 years in the three patients in whom follow-up was long enough. Different types of PD were seen including paroxysmal kinesigenic dyskinesia (one patient), paroxysmal exercise-induced dystonia (three patients), and paroxysmal tonic upgaze (two siblings). In most patients, PD appeared at a later age than, co-occurred with, and outlasted absence seizures. Only in the two siblings with tonic upgaze, dyskinetic attacks had an earlier onset. PD improved with increasing age and did not usually produce severe disability. CONCLUSIONS: There is a widening spectrum of epilepsy and PD syndromes, within which epilepsy has the characteristics of the common idiopathic syndromes, with some atypical features.

Adolescent↗
PubMed1995

Effects of remacemide and its metabolite FPL 12495 on spike-wave discharges, electroencephalogram and behaviour in rats with absence epilepsy.

The effects of the anti-convulsant drug remacemide and one of its active metabolites FPL 12495 were examined in a genetic model for generalized absence epilepsy, the WAG/Rij strain of rats. Number, mean and total duration of spike-wave discharges were measured following oral administration of remacemide and FPL 12495, together with parameters of background electroencephalographic activity (EEG) and spontaneous behaviour in the recording cage. A decrease in the number of the spike-wave discharges was found after remacemide administration. At the highest dose there was near total suppression of the spike-wave discharges. There were no important effects on behaviour and on spectral content of the background EEG, suggesting that remacemide has little side effects. A decrease in the number of spike-wave discharges was also found after FPL 12495 gavage and there was a prolongation of the mean duration. Behavioural changes were only noticed after the highest dose. These were accompanied by changes in the spectral content and particularly by an increase in the amplitude of the delta and the high beta frequencies, together with a decrease in the spindle frequency range. FPL 12495 appeared to be more potent that remacemide in all its effects. The effects of mainly FPL 12495 are uncommon in the sense that so far no other investigated drug shows a decrease in the number together with an increase in the mean duration of the discharges. It seems that in contrast to other anti-epileptic drugs, FPL 12495 exerts a differential action on the two commonly distinguished mechanisms controlling number and duration.

Acetamides↗
PubMed1996

Long-term prognosis of typical childhood absence epilepsy: remission or progression to juvenile myoclonic epilepsy.

OBJECTIVE: To determine the proportion and characteristics of children presenting with childhood absence epilepsy (CAE) who were not taking anti-epileptic drugs (AEDs) and were seizure-free over the last year of long-term follow-up. METHODS: For case finding, centralized EEG records for the province of Nova Scotia allowed identification of all children with typical CAE diagnosed between 1977 and 1985. Follow-up was done in 1994 to 1995. RESULTS: Of 81 children with CAE, 72 (89%) were contacted for follow-up. Mean age at seizure onset was 5.7 years (range, 1 to 14 years) and at follow-up was 20.4 years (range, 12 to 31 years). Forty-seven (65%) were in remission. Twelve others (17%) were not taking AEDs but continued to have seizures. Thirteen (18%) were taking AEDs; five were seizure-free over the last year (in four of these a trial without AEDs had previously failed). Fifteen percent of the total cohort had progressed to juvenile myoclonic epilepsy (JME). Multiple clinical and EEG factors were examined as predictors of outcome. Factors predicting no remission (p < 0.05) included cognitive difficulties at diagnosis, absence status prior to or during AED treatment, development of generalized tonic clonic or myoclonic seizures after onset of AEDs, abnormal background on initial EEG, and family history of generalized seizures in first-degree relatives. CONCLUSIONS: Only 65% of children presenting with CAE had remission of their epilepsy. Forty-four percent of those without remission had developed JME. At the time of diagnosis, remission is difficult to predict accurately in most patients. However, development of generalized tonic-clonic seizures or myoclonic seizures during AED treatment is ominous, predicting both lack of remission of CAE and progression to JME.

Child, Preschool↗
PubMed1996

No loss in total neuron number in the thalamic reticular nucleus and neocortex in the genetic absence epilepsy rats from Strasbourg.

The thalamic reticular nucleus (nRt) as well as the neocortex are involved in the bilateral spike- and wave-discharge loop in genetic absence epilepsy rats from Strasbourg (GAERS). Neuron loss in different brain areas has been described in relation to epilepsy with convulsive seizures. We have previously investigated the ventrolateral/posterior nucleus of thalamus in GAERS and found no neuron loss. We applied the same efficient and unbiased stereological methods to nRt and to neocortex and again found no loss of neurons. The oscillatory properties of nRt are not related to neurons loss.

Animals↗
PubMed2002

[Association analysis of childhood absence epilepsy by microsatellite DNA].

OBJECTIVE: To investigate whether or not the gamma-aminobutyric acid GABA receptor subtype Alpha genes GABRA5 and GABRB3 are associated with childhood absence epilepsy CAE . METHODS: Five microsatellite DNA 69CA 85CA 155CA1 155CA2 and A55CA1 adjacent to chromosome 15q11-15q13 were used as genetic markers. Fluorescence-based semi-automated genotyping technique was used in 90 CAE patients and 100 normal controls to conduct genotyping. Case-control study was used to do association analysis. RESULTS: In Chinese normal population the allele frequencies of the five microsatellite DNAs were in good agreement with Hardy- Weinberg equilibrium. The polymorphism information content PIC of the five microsatellite DNA were 0.47 0.82 0.66 0.86, and 0.86 respectively. The frequencies of some alleles of the 5 microsatellite DNAs in CAE patients were significantly higher than those in normal controls. CONCLUSION: Four of the five microsatellite DNAs are good genetic markers. GABA subtype Alpha genes GABRA5 and GABRB3 may be associated with the pathogenic mechanism of CAE.

Adolescent↗
PubMed1995

Impairment of intracortical GABAergic inhibition in a rat model of absence epilepsy.

The WAG/Rij rat strain is characterized in its EEG by the manifestation of spike-wave discharges which resemble in their spontaneous appearance and pharmacological sensitivity the absence epilepsy observed in humans. In order to test the hypothesis whether cellular intrinsic membrane and/or synaptic network properties in the neocortex are modified in this form of epilepsy, we analyzed with extra- and intracellular recording techniques the functional status of neocortical slices obtained from adult epileptic WAG/Rij rats and compared them with the data acquired from non-epileptic control Wistar rats. Intrinsic membrane properties, like resting membrane potential, neuronal input resistance and basic cellular firing characteristics, did not differ between these two strains. However, the analysis of extra- and intracellularly recorded synaptic responses revealed an intracortical hyperexcitability which was accompanied by a significant reduction in the efficiency of GABAergic inhibition. Our data indicate that the imbalance between intracortical excitatory and inhibitory mechanisms may at least contribute to the expression and augmentation of spike-wave discharges in epileptic WAG/Rij rats.

Animals↗
PubMedDate not supplied

Epidemiology of absence epilepsy: EEG findings and their predictive value.

This population-based study of absence epilepsy comprised 97 children, ranging in age from newborns to 15 years. All had regular bilaterally synchronous and symmetric 2-4 Hz spike-and-slow wave discharges and absences with or without generalized tonic-clonic seizures (GTCS). Patients without GTCS tended to have long episodes of 2-4 Hz spike-and-slow wave discharges (greater than or equal to 10 sec), and simultaneous clinical correlates more frequently than those with GTCS. Posterior delta rhythm was found only in patients without GTCS. Focal abnormalities, albeit transient, were more frequent among patients with GTCS. The initial electroencephalogram was of some early predictive value in patients with only absences at the time of the initial registration. Brief episodes of 2-4 Hz spike-and-slow wave (less than 10 sec) without clinical correlates were associated with a slightly increased risk of future GTCS.

Adolescent↗
PubMed2004

The GABAA receptor gamma2 subunit R43Q mutation linked to childhood absence epilepsy and febrile seizures causes retention of alpha1beta2gamma2S receptors in the endoplasmic reticulum.

The GABA(A) receptor gamma2 subunit mutation R43Q is an autosomal dominant mutation associated with childhood absence epilepsy and febrile seizures. Previously, we demonstrated that homozygous alpha1beta3gamma2L(R43Q) receptor whole-cell currents had reduced amplitude with unaltered time course, suggesting reduced cell surface expression of functional receptors. In human embryonic kidney 293-T cells, we demonstrate that both heterozygous and homozygous alpha1beta2gamma2S(R43Q) GABA(A) receptor current amplitudes were reduced when receptors were assembled from coexpressed alpha1, beta2, and gamma2S subunits and from beta2-alpha1 tandem subunits coexpressed with the gamma2L subunit. Using fluorescence confocal microscopy, we demonstrated that mutant receptors containing enhanced yellow fluorescent protein-tagged gamma2S subunits had reduced surface expression and were retained in the endoplasmic reticulum. In addition, using biotinylation of surface receptors and immunoblotting, we confirmed that alpha1beta2gamma2S(R43Q) receptors had reduced surface expression. These results provide evidence that the gamma2S(R43Q) mutation impaired GABA(A) receptor function by compromising receptor trafficking and reducing surface expression.

Animals↗
PubMed1992

Nonconvulsive electrocorticographic paroxysms (absence epilepsy) in rat strains.

Rat strains were screened for evidence of unresponsive periods associated with high-voltage spike and wave paroxysms on electroencephalography--a rodent model of human absence epilepsy. Five commonly used strains were newly noted to express the spike and wave phenomenon. Only an inbred Sprague Dawley rat strain did not exhibit such episodes. The existence of the phenomenon in many and unrelated inbred rat strains suggests that both genetic and environmental factors are causal.

Animals↗
PubMed1991

CNQX, a new non-NMDA receptor antagonist, reduces spike wave discharges in the WAG/Rij rat model of absence epilepsy.

The effects on seizures, EEG and behavior of the non-NMDA receptor antagonist CNQX (6-cyano-7-nitroquinoxaline-2,3-dione), were studied in the WAG/Rij rat with absence epilepsy. Intracerebroventricular injections (10, 50, and 100 nmol/5 microliters CNQX) showed that CNQX decreases the number of spike wave discharges in a dose-dependent way. Coinjection of CNQX (100 nmol/5 microliters) and AMPA (0.1 pmol/5 microliters), kainic acid (0.01 nmol/5 microliters) or NMDA (50 pmol/5 microliters) attenuated the CNQX response, indicating that CNQX acts on both non-NMDA and NMDA receptors. The observed effects appear to be specific manipulations of the epilepsy not mediated by behavioral changes.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed2003

5-HT2C receptors inhibit and 5-HT1A receptors activate the generation of spike-wave discharges in a genetic rat model of absence epilepsy.

The present study was conducted to investigate the role of 5-HT(2C) and 5-HT(1A) receptors in the generation of spike-wave discharges (SWD) in the genetic absence epilepsy model Wistar Albino Glaxo rats from Rijswijk, Netherlands (WAG/Rij rats). We have determined the effects of the 5-HT(2C) receptor preferring agonist m-chlorophenyl-piperazine (m-CPP), the selective 5-HT(2C) receptor antagonist SB-242084, the selective 5-HT(1A) receptor antagonist WAY-100635, two selective serotonin re-uptake inhibitors (SSRI, fluoxetine and citalopram) and their combinations in this model. The 5-HT(2C) agonist m-CPP caused marked, dose-dependent decreases in the cumulative duration and number of SWD administered either intraperitoneally (0.9 and 2.5 mg/kg) or intracerebroventricularly (0.05 and 0.1 mg/kg). Treatment with SB-242084 (0.2 mg/kg, ip) alone failed to cause any significant change in SWD compared to vehicle. Pretreatment with SB-242084 (0.2 mg/kg, ip) eliminated the effects of m-CPP on SWD. Fluoxetine (5.0 mg/kg, ip) alone caused moderate increase in SWD. After pretreatment with SB-242084, the effect of fluoxetine was significantly enhanced. The combination of SB-242084 and citalopram (2.5 mg/kg, ip) caused a similar effect, namely an increase in SWD. In contrast, pretreatment with WAY-100635 significantly attenuated the effect of fluoxetine. In conclusion, these results indicate that the increase in endogenous 5-HT produces a dual effect on SWD; the inhibition of epileptiform activity is mediated by 5-HT(2C), the activation by 5-HT(1A) receptors.

Action Potentials↗
PubMed2000

Glial glutamate transporter mRNAs in the genetically absence epilepsy rat from Strasbourg.

Recent studies support a critical role for the glutamatergic system and glutamate transporters in the pathogenesis of epilepsy. The glial glutamate transporters GLT-1 (L-glutamate transporter) and GLAST (L-glutamate/L-aspartate transporter) are known to be responsible for the majority of glutamate reuptake from the synaptic cleft and constitute one mechanism by which extracellular glutamate levels may be controlled. The present study therefore compared GLT-1 and GLAST mRNA levels in the genetically absence epilepsy rat from Strasbourg (GAERS) with those of age-matched non-epileptic controls. The GAERS rat has been proposed as an animal model of inherited human absence epilepsy, displaying recurrent, generalised, non-convulsive seizures that originate from thalamic and cortical structures. In situ hybridisation with 35S-labelled oligonucleotide probes demonstrated substantial and significant increases in GLT-1 mRNA levels in the ventromedial nucleus of the thalamus (VM) and the subthalamic nucleus (STN) of GAERS rats. Increases in GLAST mRNA were found in the primary somatosensory cortex (SS1) and temporal cortex (Te) of GAERS. These data, along with previous studies, suggest that regional imbalances in GABAergic and glutamatergic systems may be associated with the pathogenesis of absence seizures in GAERS.

ATP-Binding Cassette Transporters↗