Absence epilepsy

The present studies sought to determine the concentrations of endogenous kynurenic acid (KYNA) and to measure the activity of kynurenine aminotransferases (KAT) I and II in the discrete brain regions of 3- and 6-month old WAG/Rij rats, a genetic model of absence epilepsy. Analogues experiments were performed using age-matched ACI rats, which served as a non-epileptic control. The age-dependent increase in KYNA concentration in the frontal cortex of WAG/Rij rats was considerably reduced in comparison to what was found in ACI rats. Consequently, the concentration of KYNA in the frontal cortex of epileptic rats was significantly lower than in non-epileptic controls. There were no such strain differences in other brain regions. The activities of KAT I and II also showed age-dependent increase with an exception for KAT II in the frontal cortex. Our data suggest that selective deficits of endogenous KYNA may account for increased excitability in the frontal cortex, which in turn may lead ...

Recalling the concept of "epilepsy", already analyzed in a previous publication, this work focuses on the specific study of the best pharmacological treatments for the morbid condition under examination, paying attention to the clinical and prospective aspects of therapy, also in light of recent discoveries in the neuroinflammatory and neurogenetic field.

In this study, the effects of vigabatrin on spike-and-wave discharges (SWDs) were measured in WAG/Rij rats, an animal model of absence epilepsy. Vigabatrin was used with the aim of enhancing GABAergic neurotransmission, and in this way to investigate the role of this process in the properties of SWDs. The study was carried out both in the rat, in vivo, and also using a computational model, in order to test different mechanisms that may account for the changes in SWDs after vigabatrin. The model parameters, representing GABA levels, were changed according to the known, and assumed, mechanism of action of the drug. The results show that the computational model can most adequately simulate the data obtained in vivo on the assumption that the enhancement of GABAergic neurotransmission due to application of vigabatrin is most pronounced at the level of the thalamic relay nuclei (TC cells). Furthermore, vigabatrin was shown to affect both the SWD starting and stopping mechanisms, as refle...

SUMMARY Purpose: To better understand the nature of the focal spike-wave discharges (FSWDs) and focally led generalized spike-wave discharges (GSWDs) in typical childhood absence epilepsy (CAE) and by implication their nosologic and taxonomic significance. Methods: Twenty-four abnormal video-electroencephalography (EEG) studies from 13 consecutive children with CAE and good response to appropriate antiepileptic drugs (AEDs) were analyzed. We studied the association between the topography of absence onset and the ictal automatisms, and the topographic correlation between FSWDs and GSWDs and their respective behavior during hyperventilation and the different states of phasic and nonphasic non–rapid eye movement (NREM) sleep. GSWDs were considered as of ''focal'' onset if a lead-in could be visibly recognized at a paper speed of 60 mm/s, and were classified by their topography. Key Findings: (1) Multifocal absences occurred in 10 children; anterior onset was noted in 81 absences (73.6%) from 12 children and posterior in 18 (16.4%) from 7 children; there was no association between topography of absence onset and ictal automatisms; (2) FSWDs occurred in 85% of children and were multifocal in 73% of them; 85% of FSWDs were anterior and 14% posterior; (3) there was good topographic association between FSWDs and the leading spike of GSWDs of ''focal'' onset in all children with FSWDs; (4) both FSWDs and GSWDs increased during hyperventilation; (5) FSWDs occurred mainly during noncyclical NREM sleep and during periods of reduced vigilance of cyclical NREM sleep, whereas GSWDs occurred during the periods of enhanced vigilance of NREM sleep; GSWDs occurred significantly more frequently than FSWDs at the transition from reduced to enhanced vigilance of NREM sleep. Significance: Our findings suggest that in CAE focal EEG paroxysms reflect a system of multifocal nonlocalizing electrically unstable cortical areas that under the facilitatory influence of exogenous or endogenous factors like sleep instability can foster a corticothalamic response of sufficient strength to generate 3-Hz GSWDs that are conditionally sustainable and potentially ictal. FSWDs can be viewed as incomplete forms of the GSWDs; together they define the EEG identity of idiopathic ''generalized'' epileptogenesis.

Clinically shown to have an effect on motor and cognitive disturbances of the nerve cells of the brain, absence seizures are often associated with impaired or loss of consciousness. Seizures are caused by a variety of etiopathophysiological events that result in neurobiological changes in the central nervous system's reticulothalamocortical circuitry zones. This allows for absence seizure episodes to occur. A 24-year-old adult patient with diminished consciousness presented to the hospital with an absence seizure. The patient's brain magnetic resonance imaging scan revealed a small focal flair hypertensive area near the cavernous sinus in the right parasellar region, as well as moderate flair hypersensitivity in the left cavernous sinuses, right maxillary, and ethmoid sinusitis. Regular waves with electrode objects were seen on the electroencephalogram of the brain. The patient was diagnosed with absence seizures and was given epival 500 mg twice daily to treat them. The patient was able to recover from his seizure and was given treatment before being released. Once every eight week, he was summoned for a checkup.

Summary: A girl aged 5 years developed nocturnal seizures (mouth twitching, salivation, anarthria, with right arm jerking and occasional secondary generalisation), with frequent focal sharp waves over the left centrotemporal region in her EEG, suggesting benign childhood epilepsy with centrotemporal spikes (BECTS). Seizures became diurnal and frequent, not modified by carbamazepine (CBZ) or valproate (VPA) but responding to VPA and lamotrigine (LTG) with recommended dosage schedules for this combination.Her school performance then deteriorated insidiously, with poor memory and concentration, clumsiness, stuttering, and emotional lability. After 4 months, new episodes, ≥10 per day, occurred. These lasted a few seconds; she stared into space, her jaw dropped, her head dropped to the right, and her eyelids flickered. She usually maintained awareness. Attacks were often provoked by blowing or sneezing. Ictal EEG showed anterior-predominant 3/s sharp-slow wave complexes lasting ≥8 s, with bilateral rolandic discharges interictally. Withdrawal of LTG resulted in rapid improvement in cognitive function and gradual remission of the new attacks.Conclusions: This appears to be a paradoxic reaction to LTG in the setting of BECTS.

Perioral myoclonia with absences belongs to the "idiopathic generalised epilepsy syndromes in development", currently not yet cited in the ILAE classification. This epilepsy syndrome is associated with a seizure type that appears to be specific. Here, we report polygraphic recordings of this seizure type in a young boy, previously misdiagnosed with focal epilepsy. EEG and clinical features were useful to differentiate diagnosis of his seizures from other absence or myoclonic seizures. Interestingly, some seizures were associated with neck myoclonia. Home video recording of myoclonic status aggravated by inappropriate treatment is also presented. [Published with video sequences].