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Query: UMLS:C0036572 (seizures)
 80,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mutations in several classes of embryonically-expressed transcription factor genes are associated with behavioral disorders and epilepsies. However, there is little known about how such genetic and neurodevelopmental defects lead to brain dysfunction. Here we present the characterization of an epilepsy syndrome caused by the absence of the transcription factor SOX1 in mice. In vivo electroencephalographic recordings from SOX1 mutants established a correlation between behavioral changes and cortical output that was consistent with a seizure origin in the limbic forebrain. In vitro intracellular recordings from three major forebrain regions, neocortex, hippocampus and olfactory (piriform) cortex (OC) showed that only the OC exhibits abnormal enhanced synaptic excitability and spontaneous epileptiform discharges. Furthermore, the hyperexcitability of the OC neurons was present in mutants prior to the onset of seizures but was completely absent from both the hippocampus and neocortex of the same animals. The local inhibitory GABAergic neurotransmission remained normal in the OC of SOX1-deficient brains, but there was a severe developmental deficit of OC postsynaptic target neurons, mainly GABAergic projection neurons within the olfactory tubercle and the nucleus accumbens shell. Our data show that SOX1 is essential for ventral telencephalic development and suggest that the neurodevelopmental defect disrupts local neuronal circuits leading to epilepsy in the SOX1-deficient mice.
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PMID:Sox1-deficient mice suffer from epilepsy associated with abnormal ventral forebrain development and olfactory cortex hyperexcitability. 1277 May 56

Despite advances in neuroimaging techniques over the past three decades that have helped in identifying structural lesions of the central nervous system, electroencephalography (EEG) continues to provide valuable insight into brain function by demonstrating focal or diffuse background abnormalities and epileptiform abnormalities. It is an extremely valuable test in patients suspected of epilepsy and in patients with altered mental status and coma. Patterns in the EEG make it possible to clarify the seizure type; it is indispensable for the diagnosis of nonconvulsive status epilepticus and for separating epileptic from other paroxysmal (nonepileptic) episodes. There are EEG patterns predictive of the cause of the encephalopathy (i.e., triphasic waves in metabolic encephalopathy) or the location of the lesion (i.e., focal polymorphic delta activity in lesions of the subcortical white matter). The various EEG characteristics of infantile, childhood, and adult epilepsies are described as well as the EEG patterns that are morphologically similar to interictal/ictal epileptiform discharges but unrelated to epilepsy. An EEG is most helpful in determining the severity and, hence, the prognosis of cerebral dysfunction. Lastly, EEG is extremely helpful in assessing normal or abnormal brain functioning in a newborn because of the serious limitation in performing an adequate neurologic examination on the neonate who is intubated or paralyzed for ventilatory control. Under such circumstances, the EEG may be the only available tool to detect an encephalopathic process or the occurrence of epileptic seizures.
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PMID:Pearls, perils, and pitfalls in the use of the electroencephalogram. 1287 Jan 4

The success of cortical resection for intractable epilepsy of neocortical origin is highly dependent on the accurate presurgical delineation of the regions responsible for generating seizures. In addition to EEG and structural imaging studies, functional neuroimaging such as positron emission tomography (PET) can assist lateralization and localization of epileptogenic cortical areas. In the presented studies, objectively delineated focal PET abnormalities have been analyzed in patients (mostly children) with intractable epilepsy, using two different tracers: 2-deoxy-2-[18F]fluoro-D-glucose (FDG), that measures regional brain glucose metabolism, and [11C]flumazenil (FMZ), that binds to GABAA receptors. The PET abnormalities were correlated with scalp and intracranial EEG findings, structural brain abnormalities, as well as surgical outcome data. In patients with extratemporal foci and no lesion on MRI, FMZ PET was more sensitive than FDG PET for identification of the seizure onset zone defined by intracranial EEG monitoring. In contrast, seizures commonly originated from the border of hypometabolic cortex detected by FDG PET suggesting that such areas are most likely epileptogenic, and should be addressed if subdural EEG is applied to delineate epileptic cortex. In patients with cortical lesions, perilesional cortex with decreased FMZ binding was significantly smaller than corresponding areas of glucose hypometabolism, and correlated well with spiking cortex. Extent of perilesional hypometabolism, on the other hand, showed a correlation with the life-time number of seizures suggesting a seizure-related progression of brain dysfunction. FMZ PET proved to be also very sensitive for detection of dual pathology (coexistence of an epileptogenic cortical lesion and hippocampal sclerosis). This has a major clinical importance since resection of both the cortical lesion and the atrophic hippocampus is required to achieve optimal surgical results. Finally, the author demonstrated that in patients with neocortical epilepsy, FDG PET abnormalities correctly regionalize the epileptogenic area, but their size is not related to the extent of epileptogenic tissue to be removed. In contrast, complete resection of cortex with decreased FMZ binding predicts good surgical outcome suggesting that application of FMZ PET can improve surgical results in selected patients with intractable epilepsy of neocortical origin.
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PMID:Positron emission tomography in presurgical localization of epileptic foci. 1297 Nov 20

Many anecdotal cases and some clinical studies have demonstrated that formaldehyde exposure can cause multiple health-related problems and cerebral dysfunction. The U.S. Consumer Product Safety Commission has documented multiple hazards related to formaldehyde exposure. Some of this research has suggested that low levels of exposure can be very hazardous to one's health and can potentially result in heightened chemical sensitivities, seizures, and cognitive decline. Some research suggests that exposure results in long-term immunological changes, cell neurofilament protein changes, and demyelination. Symptomatically, exposure has been associated with respiratory problems, excessive fatigue, headaches, mood changes, and impaired attention, concentration, and memory functioning. This article outlines the case of a biology teacher whose chronic formaldehyde exposure resulted in heightened sensitivity to formaldehyde, three tonic-clonic seizures, and dramatic amnesia as well as other cognitive dysfunction.
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PMID:A case of claimed persistent neuropsychological sequelae of chronic formaldehyde exposure: clinical, psychometric, and functional findings. 1459 Jan 91

Patients with nonepileptic seizures (NES), those with epileptic seizures (ES), and normal controls were compared on a battery of neuropsychologic tests. Diagnoses were made after intensive electroencephalogram (EEG) monitoring. Excluded from the study were patients with both ES and NES, as well as patients with ES who had evidence of structural brain damage. On all neuropsychologic measures, the two seizure groups were significantly impaired relative to the controls, but there were no significant differences between the ES and NES group performances. Additional neuropsychologic measures were obtained on the two seizure groups but not controls, and again there were no significant differences between the two seizure groups. Further analyses suggested that the NES group's impairment was related to emotional factors. The Minnesota Multiphasic Personality Inventory (MMPI)/MMPI-2 and the Portland Digit Recognition Test were helpful in classifying patients by seizure group. Our results, which are consistent with those of previous studies, suggest that neuropsychologic abnormalities are not pathognomonic of brain dysfunction in this population. However, the Portland Digit Recognition Test (PDRT) and measures of personality are useful for classification purposes in the differential diagnosis of epileptic and nonepileptic seizures.
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PMID:Neuropsychologic impairment in patients with nonepileptic seizures. 1459 Jun 35

The epilepsies are a complex group of disorders commonly associated with brain dysfunction, social isolation, and vocational difficulty. Each of these factors may contribute to increased prevalence of depressive disorders in epilepsy, but the specific mechanisms are not completely understood. The brain regions commonly involved in various types of epilepsies, such as the hippocampus and amygdala in temporal lobe epilepsy and subcortical nuclei in idiopathic generalized epilepsies, are important components of current models of depression. Increased understanding of mechanisms of depression in epilepsy is not only crucial for improving care of many persons with seizures, but may also yield useful information about principal mechanisms underlying both depression and epileptogenesis.
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PMID:Mechanisms of depression in epilepsy from a clinical perspective. 1459 37

Recently, the number of reports of encephalopathy associated with influenza has increased in Japan. The abrupt onset of seizure and coma after development of high-grade fever is a prominent indicator of CNS involvement. Approximately 600 patients have been reported during 1999-2002. 78% of them are younger than 6 yr old, and the mortality was 30% in 1999 and 2000 seasons. The pathogenicity of brain dysfunction is still unknown. However, elevation of cytokines(TNF-alpha and IL-6) and the damage of vascular endothelial cells were demonstrated. Thus, the prognosis of this illness was extremely poor. Intensive care trial in combination with (1) anti-virals, (2) high dose gamma-grobulin, (3) steroid pulse therapy. (4) high dose AT III, (5) head cooling and (6) plasma exchange has started since 2001, that could reduce the mortality from 30 to 15% in 2001 and 02. In order to establish more effective treatment, further investigation will be necessary.
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PMID:[Treatment of influenza-associated encephalopathy]. 1461 46

Positron emission tomography (PET) is a powerful clinical and research tool that, in the past two decades, has provided a great amount of novel data on the pathophysiology and functional consequences of human epilepsy. PET studies revealed cortical and subcortical brain dysfunction of a widespread brain circuitry, providing an unprecedented insight in the complex functional abnormalities of the epileptic brain. Correlation of metabolic and neuroreceptor PET abnormalities with electroclinical variables helped identify parts of this circuitry, some of which are directly related to primary epileptogenesis, while others, adjacent to or remote from the primary epileptic focus, may be secondary to longstanding epilepsy. PET studies have also provided detailed data on the functional anatomy of cognitive and behavioral abnormalities associated with epilepsy. PET, along with other neuroimaging modalities, can measure longitudinal changes in brain function attributed to chronic seizures as well as therapeutic interventions. This review demonstrates how development of more specific PET tracers and application of multimodality imaging by combining structural and functional neuroimaging with electrophysiological data can further improve our understanding of human partial epilepsy, and helps more effective application of PET in presurgical evaluation of patients with intractable seizures.
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PMID:Pathophysiology and functional consequences of human partial epilepsy: lessons from positron emission tomography studies. 1470 71

The neuronal ceroid lipofuscinoses (NCL) are a large group of autosomal recessive lysosomal storage disorders with both enzymatic deficiency and structural protein dysfunction. Previously, diagnosis of NCL was based on age at onset and clinicopathological (C-P) findings described 4 forms, classified as infantile (INCL) (2), late-infantile (LINCL) (5), juvenile (JNCL) (6), and adult (ANCL) (12). Most patients with NCL have progressive ocular and cerebral dysfunction, including cognitive/motor dysfunction and uncontrolled seizures. After reviewing 520 patients with NCL, we found that about 104 (20%) did not fit this classification of NCL. With further research, 4 additional forms have been recognized: Finnish (13), Gypsy/Indian (14), Turkish (15)--variants of LINCL, and Northern epilepsy (16), also known as progressive epilepsy with mental retardation. These eight NCL forms resulted from 151 different mutations in genes CLN1 to CLN8 causing different phenotypes (http://www.ucl.ac.uk/ncl). The genes CLN1 and CLN2 encode lysosomal palmitoyl protein thioesterase and tripeptidyl peptidase 1. The diagnosis of NCL is based on clinicopathological (C-P) findings, enzymatic assay, and molecular genetic testing. Ultrastructural studies must be performed to confirm the presence and nature of lysosomal storage material (fingerprint or curvilinear profiles, or granular osmiophilic deposits) before doing biochemical testing. Pheno/genotypic correlation studies are discussed.
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PMID:Current state of clinical and morphological features in human NCL. 1499 38

Neonatal seizures are the most common manifestation of underlying cerebral dysfunction. Hypoxic-ischemic encephalopathy is the cause of seizures in 40-60% of newborns. Previous work from our laboratory demonstrates that seizures associated with a hypoxic-ischemic insult results in aggravation of neuronal cell death, specifically within the hippocampus. The latter occurs in the setting of spontaneously occurring hyperthermia of 1.5 degrees C. The purpose of this study was to determine whether preventing the onset of seizure induced hyperthermia would be neuroprotective. Three groups of 10-day old rat pups received unilateral hypoxic-ischemic insults for 30 min followed by KA-induced seizures. Hyperthermia was prevented by lowering the environmental temperature ("relative hypothermia") to 29 degrees C such that the seizuring rat pups were normothermic. In one group, the prevention of hyperthermia occurred immediately following hypoxia-ischemia, whereas in the other group it occurred at the onset of seizures. The third group of rat pups (controls) remained at their nesting temperature and therefore became hyperthermic during seizures. Early (3 days) and late (20 days) neuropathology was assessed. Rat pups in whom hyperthermia was prevented during seizures displayed a significant reduction in brain damage compared to controls (p<0.05). Assessment of hippocampal brain damage also showed a significant improvement in neuronal necrosis at 20 days of recovery compared to 3 days of recovery (p<0.05). The results indicate that preventing spontaneous hyperthermia in this model of hypoxic-ischemic seizures in the newborn is neuroprotective.
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PMID:Preventing hyperthermia decreases brain damage following neonatal hypoxic-ischemic seizures. 1514 Jun 43


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