-
Neuroscience Letters Sep 2021The new aggregate data analyses revealed the earlier missing role of cerebellum long-term electrical stimulation in the absence epilepsy. Neurophysiologic data gained by... (Review)
Review
The new aggregate data analyses revealed the earlier missing role of cerebellum long-term electrical stimulation in the absence epilepsy. Neurophysiologic data gained by authors favor that cerebellar serial deep brain stimulation (DBS) (100 Hz) causes the transformation of penicillin-induced cortical focal discharges into prolonged 3,5-3,75 sec oscillations resembling spike-wave discharges (SWD) in cats. Such SWDs were not organized in the form of bursts and persisted continuously after stimulation. Therefore, the appearance of prolonged periods of SWD is regarded as a tonic cerebellar influence upon pacemaker of SWD and might be caused by the long-lasting DBS-induced increase of GABA-ergic extrasynaptic inhibition in the forebrain networks. The absence seizure facilitation caused by cerebellar DBS was discussed with the reviewed data on optogenetic stimulation, neuronal activity of cerebellar structures, and imaging data.
Topics: Action Potentials; Animals; Cerebellum; Epilepsy, Absence; Humans; gamma-Aminobutyric Acid
PubMed: 34256107
DOI: 10.1016/j.neulet.2021.136110 -
Seizure Jan 2017Although absence seizures do predominate in childhood they may occur at all ages and clinical presentation varies widely. Albeit considered a benign seizure type,... (Review)
Review
PURPOSE
Although absence seizures do predominate in childhood they may occur at all ages and clinical presentation varies widely. Albeit considered a benign seizure type, chronic evolution with therapeutic refractoriness is possible in some patients with absences. The aim of this paper is to summarize the main syndromic presentation of absence seizures and its outcome regarding treatment and prognosis.
METHOD
We performed a review of literature with emphasis in historic and classical manuscripts about absence epilepsy.
RESULTS
Absence was described in the beginning of last century as a seizure type with good evolution, but it is still difficult to preview a strict prognosis for an individual patient. Some positive early predictors were reported such as response to initial treatment and seizure onset in childhood. Genetic aspects are not yet well understood although some families have been reported with rare mutations in ion channel coding genes.
CONCLUSION
Absence seizures are present in different epilepsy syndromes and nosological classification is not always possible. Outcome depends on clinical variables such as age of onset, presence of other seizure types and initial response to treatment.
Topics: Anticonvulsants; Electroencephalography; Epigenomics; Epilepsy, Absence; Humans; Treatment Outcome
PubMed: 27986418
DOI: 10.1016/j.seizure.2016.11.031 -
Current Pharmaceutical Design 2017The benign character of absence epilepsy compared to other genetic generalized epilepsy syndromes has often hampered the search for new treatment options. Absence... (Review)
Review
BACKGROUND
The benign character of absence epilepsy compared to other genetic generalized epilepsy syndromes has often hampered the search for new treatment options. Absence epilepsy is most often treated with ethosuximide or valproic acid. However, both drugs are not always well tolerated or fail, and seizure freedom for a larger proportion of patients remains to be achieved. The availability of genuine animal models of epilepsy does allow to search for new treatment options not only for absence epilepsy per se but also for other genetic - previously called idiopathic - forms of epilepsy. The recent discovery of a highly excitable cortical zone in these models is considered as a new therapeutic target area.
METHODS
Here, we provide an overview regarding the search for new therapeutical options as has been investigated in the genetic rodent models (mainly WAG/Rij and GAERS) including drugs and whether antiepileptogenesis can be achieved, various types of electrical and optogenetical invasive stimulations, different types of noninvasive stimulation and finally whether absence seizures can be predicted and prevented.
RESULTS
Many factors determine either the cortical and or thalamic excitability or the interaction between cortex and thalamus and offer new possibilities for new anti-absence drugs, among others metabotropic glutamatergic positive and negative allosteric modulators. The inhibition of epileptogenesis by various drugs with its widespread consequences seems feasible, although its mechanisms remain obscure and seems different from the antiabsence action. Surgical intervention on the cortical zone initiating seizures, either with radiosurgery using synchrotron- generated microbeams, or ablation techniques might reduce spike-and-wave discharges in the rodent models. High frequency electrical subcortical or cortical stimulation might be a good way to abort ongoing spikeand- wave discharges. In addition, possibilities for prevention with real-time EEG analyses in combination with electrical stimulation could also be a way to fully control these seizures.
CONCLUSION
Although it is obvious that some of these treatment possibilities will not be used for absence epilepsy and/or need to be further developed, all can be considered as proof of principle and provide clear directives for further developments.
Topics: Animals; Anticonvulsants; Disease Models, Animal; Epilepsy, Absence; Humans
PubMed: 29046145
DOI: 10.2174/1381612823666171017170226 -
World Journal of Pediatrics : WJP Apr 2017Recent studies have shown a possible coexistence of absence seizures with other forms of epilepsy. The purpose of this study was to ascertain the possible contemporary... (Review)
Review
BACKGROUND
Recent studies have shown a possible coexistence of absence seizures with other forms of epilepsy. The purpose of this study was to ascertain the possible contemporary or subsequent presence of childhood absence epilepsy (CAE) and benign epilepsy with centro-temporal spikes (BECTS) in pediatric epileptic patients.
DATA SOURCES
A PubMed systematic search indexed for MEDLINE, PubMed and EMBASE was undertaken to identify studies in children including articles written between 1996 and 2015. Retrospective studies, meta-analysis and case reports were included. The list of references of all the relevant articles was also studied. The date of our last search was December 2015.
RESULTS
Review of the literature revealed 19 cases, 8 females and 11 males, reporting a consecutive or contemporary coexistence of CAE and BECTS within the same patients. Patient's age ranged between 4 and 12 years. Three out of 19 patients presented concomitant features of both syndromes, whereas 16 patients experienced the two syndromes at different times.
CONCLUSIONS
BECTS and CAE may be pathophysiologically related, and the two epileptic phenotypes may indicate a neurobiological continuum. Further studies are needed to elucidate a probable genetic or functional link between partial and primarily generalized electro-clinical patterns in idiopathic childhood epilepsies.
Topics: Age Factors; Anticonvulsants; Child; Child, Preschool; Disease Progression; Electroencephalography; Epilepsy, Absence; Epilepsy, Rolandic; Female; Humans; Male; Prognosis; Risk Assessment; Severity of Illness Index; Sex Factors
PubMed: 28101769
DOI: 10.1007/s12519-017-0006-9 -
Current Neuropharmacology 2017Spike-wave discharges, underlying absence seizures, are generated within a cortico-thalamo-cortical network that involves the somatosensory cortex, the reticular... (Review)
Review
BACKGROUND
Spike-wave discharges, underlying absence seizures, are generated within a cortico-thalamo-cortical network that involves the somatosensory cortex, the reticular thalamic nucleus, and the ventrobasal thalamic nuclei. Activation of T-type voltage-sensitive calcium channels (VSCCs) contributes to the pathological oscillatory activity of this network, and some of the first-line drugs used in the treatment of absence epilepsy inhibit T-type calcium channels. The α2δ subunit is a component of high voltage-activated VSCCs (i.e., L-, N-, P/Q-, and R channels) and studies carried out in heterologous expression systems suggest that it may also associate with T channels. The α2δ subunit is also targeted by thrombospondins, which regulate synaptogenesis in the central nervous system.
OBJECTIVE
To discuss the potential role for the thrombospondin/α2δ axis in the pathophysiology of absence epilepsy.
METHODS
We searched PubMed articles for the terms "absence epilepsy", "T-type voltage-sensitive calcium channels", "α2δ subunit", "ducky mice", "pregabalin", "gabapentin", "thrombospondins", and included papers focusing this Review's scope.
RESULTS
We moved from the evidence that mice lacking the α2δ-2 subunit show absence seizures and α 2δ ligands (gabapentin and pregabalin) are detrimental in the treatment of absence epilepsy. This suggests that α2δ may be protective against absence epilepsy via a mechanism that does not involve T channels. We discuss the interaction between thrombospondins and α2δ and its potential relevance in the regulation of excitatory synaptic formation in the cortico-thalamo-cortical network.
CONCLUSION
We speculate on the possibility that the thrombospondin/α2 δ axis is critical for the correct functioning of the cortico-thalamo-cortical network, and that abnormalities in this axis may play a role in the pathophysiology of absence epilepsy.
Topics: Animals; Calcium Channels; Epilepsy, Absence; Humans; Thrombospondins
PubMed: 28290248
DOI: 10.2174/1570159X15666170309105451 -
Revue Neurologique Dec 1999Absence status (AS), or "Petit Mal status" is a polymorphic condition that can complicate many epileptic syndromes. Diagnosis is difficult on the basis of clinical... (Review)
Review
Absence status (AS), or "Petit Mal status" is a polymorphic condition that can complicate many epileptic syndromes. Diagnosis is difficult on the basis of clinical semiology alone, and requires emergency EEG. Although heterogeneous, the most typical ictal pattern is constituted by slow generalized rhythmic spike-waves (SW) or polyspike-waves (PSW) complexes. In a number of cases, clinical and EEG normalization is obtained after intravenous (i.v.) benzodiazepine (BZ) injection. In some difficult cases, neuropsychological investigations before and after BZ injection is useful: a significant improvement of the neuropsychological score should occur following BZ injection. On a nosographic point of view, literature data indicate that 4 types of AS may be recognized. Typical AS occurs as part of an idiopathic generalised epilepsy most often characterized by absences. Isolated impairment of consciousness, at times with subtle jerks of the eyelids, is the essential symptomatology. The EEG correlates with repetitive absence seizures and shows symmetric and bilateral synchronous SW or PSW complexes faster than 3 Hz. The immediate prognosis is excellent. Atypical AS occurs in patients with symptomatic or cryptogenic generalized epilepsies and is characterized by a fluctuating confusional state with more prominent tonic and/or myoclonic and/or lateralized ictal manifestations than occur in typical AS. The EEG shows continuous or intermittent diffuse irregular slow SW or PSW complexes. The immediate prognosis is guarded, as these episodes tend to recur and to be resistant to medication. "De novo" absence status of late onset is characterized by toxic or metabolic precipitating factors in middle-aged or elderly subjects with no previous history of epilepsy. Patients often have a history of psychiatric illness with multiple psychotropic drug intake. The electroclinical characteristics and the immediate prognosis are variable. These episodes of AS generally represent acute symptomatic seizures and may not recur if the triggering factors can be controlled or corrected. Long-term antiepileptic drugs may thus not be needed. Absence status with focal characteristics occur in subjects with a pre-existing or newly developing partial epilepsy, most often of extra-temporal origin. The EEG shows bilateral but often asymmetric ictal discharges. The immediate prognosis is variable. Some of these cases are difficult to distinguish from complex partial status epilepticus of frontal lobe origin.
Topics: Acute Disease; Benzodiazepines; Consciousness Disorders; Diagnosis, Differential; Electroencephalography; Epilepsy, Absence; Humans; Neuropsychological Tests; Prognosis
PubMed: 10637922
DOI: No ID Found -
Archives de Pediatrie : Organe Officiel... Nov 2016Childhood absence epilepsy (CAE) is a common pediatric epilepsy syndrome accounting for 10% of all pediatric epilepsies. The aim of this review is to provide an updated... (Review)
Review
Childhood absence epilepsy (CAE) is a common pediatric epilepsy syndrome accounting for 10% of all pediatric epilepsies. The aim of this review is to provide an updated overview of this epilepsy syndrome to pediatricians. Most of the patients can be initially managed in private practice or in general pediatric settings. Absence seizures are the only seizure type observed at the time of diagnosis in these patients. An electroencephalogram recording and a clinical evaluation lead to the diagnosis. The underlying mechanisms are not yet fully understood. CAE is considered a self-limited epilepsy syndrome since most of the patients will become seizure free. Only a few patients (5-10%) have resistant CAE. However, CAE, as well as any pediatric epilepsy syndrome, should not be considered a "benign" epilepsy. Attention deficit is observed in about one third of the patients. There is also an increased risk of academic difficulties related to specific cognitive disorders. Therefore, the early detection of children at risk of developing neuropsychological problems can be helpful for preventing school underachievement and poor psychosocial outcome. Recently, several studies including a large randomized controlled trial indicated that ethosuximide should be considered as a first-line treatment and valproate as a second-line treatment. Cognitive side effects should be an important factor in the selection of the antiepileptic drug and should be specifically assessed during the follow-up. This review concludes by discussing the criteria that might lead to referring the patient to a specialist.
Topics: Anticonvulsants; Attention Deficit Disorder with Hyperactivity; Child; Cognition Disorders; Diagnosis, Differential; Drug Resistance; Electroencephalography; Epilepsy, Absence; Humans; Prognosis
PubMed: 27683026
DOI: 10.1016/j.arcped.2016.08.005 -
Pediatric Neurology Mar 2014Childhood absence epilepsy is an age-dependent, idiopathic, generalized epilepsy with a characteristic seizure appearance. The disorder is likely to be multifactorial,... (Review)
Review
BACKGROUND
Childhood absence epilepsy is an age-dependent, idiopathic, generalized epilepsy with a characteristic seizure appearance. The disorder is likely to be multifactorial, resulting from interactions between genetic and acquired factors, but the debate is still open. We review recent studies on different aspects of childhood absence epilepsy and also to describe new concepts.
METHODS
Data for this review were identified using Medline and PubMed survey to locate studies dealing with childhood absence epilepsy. Searches included articles published between 1924 and 2013.
RESULTS
The diagnosis comprises predominant and associated seizure types associated with other clinical and electroencephalographic characteristics. Many studies have challenged the prevailing concepts, particularly with respect to the pathophysiological mechanisms underlying the electroencephalographic seizure discharges. Childhood absence epilepsy fits the definition of system epilepsy as a condition resulting from the persisting susceptibility of the thalamocortical system as a whole to generate seizures. This syndrome, if properly defined using strict diagnostic criteria, has a good prognosis. In some cases, it may affect multiple cognitive functions determining risk for academic and functional difficulties; the detection of children at risk allows tailored interventions. Childhood absence epilepsy is usually treated with ethosuximide, valproate, lamotrigine, or levetiracetam, but the most efficacious and tolerable initial empirical treatment has not been well defined.
CONCLUSIONS
We review recent studies and new concepts on the electroclinical features and pathophysiological findings of childhood absence epilepsy in order to highlight areas of consensus as well as areas of uncertainty that indicate directions for future research.
Topics: Animals; Anticonvulsants; Brain; Child; Epilepsy, Absence; Humans
PubMed: 24530152
DOI: 10.1016/j.pediatrneurol.2013.10.009 -
Neurology Oct 2013Clinicians typically breathe a sigh of relief when they make the diagnosis of childhood absence epilepsy. The history is classic-a normal young child with myriad brief...
Clinicians typically breathe a sigh of relief when they make the diagnosis of childhood absence epilepsy. The history is classic-a normal young child with myriad brief periods of staring. The clinic visit is powerful when the phenomena are replicated by having the child hyperventilate. Finally, the EEG is definitive. The ability to demonstrate to a family the abrupt eruption and cessation of spike-wave activity provides a framework for them to understand what is happening to their child. Parents are usually reassured that there are very good therapies, that seizures are typically controlled, and that their child will "outgrow" it. However, data from the multicenter Childhood Absence Epilepsy Study Group are rewriting this narrative.(1-3.)
Topics: Child; Electroencephalography; Epilepsy, Absence; Humans
PubMed: 24089389
DOI: 10.1212/WNL.0b013e3182a9f57b -
Trends in Pharmacological Sciences Oct 2003
Comparative Study Review
Topics: Animals; Anticonvulsants; Child; Disease Models, Animal; Electroencephalography; Epilepsy, Absence; Humans
PubMed: 14559407
DOI: 10.1016/j.tips.2003.08.006