Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036572 (seizures)
 80,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Memory impairment was demonstrated in a sample of 46 children and adolescents with brain tumors. The overall distribution of memory scores was skewed positively; over half of the total number of test measures were in the lowest quarter of the score distribution; and more than three-quarters of the individual subjects had at least one memory score in the impaired range. Verbal intelligence accounted for less than one-quarter of the variance in memory scores. The type of memory impairment was analyzed in relation to various demographic and medical variables: age at onset of tumor symptoms, age or duration of tumor, sex, pre-tumor developmental disturbances, pre-tumor closed head injury, post-tumor anticonvulsant treatment and post-tumor epileptic seizures. The working memory task, in which each in a succession of heard words is stored in temporary memory long enough to be compared to or contrasted with incoming words, was unaffected by these variables, as was memory for semantically-based word-picture associations. Memory for the serial order of pictures that corresponded to heard words varied inversely with the age at tumor onset such that the later the onset, the lower the memory test performance.
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PMID:Brain tumors in children and adolescents--I. Effects on working, associative and serial-order memory of IQ, age at tumor onset and age of tumor. 194 80

Event-related potentials were recorded over occipital and parietal scalp from 20 patients suffering from intractable partial complex seizures prior to undergoing a temporal lobectomy. Subjects were presented with language and nonlanguage visual stimuli using a divided-field, "odd-ball" paradigm. Although behavioral performance (button-press accuracy, reaction time, and running counts) was comparable across all groups (although accuracy was worse for those in the left temporal group), patients showed tremendous variability in both the amplitude and latency of the P300 response. Particularly notable was the observation that more slow wave activity was present among the patients than among the control subjects, and those scheduled for a left temporal resection evinced more amplitude reduction than those scheduled for a right temporal resection. In addition, a number of patients appeared not to show a P300 response at all. These results are discussed in the context of the utility of using noninvasive event-related potential measures to examine both memory impairment and the integrity of the neural structures that mediate memory functioning in certain patient populations.
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PMID:P300 brain activity in seizure patients preceding temporal lobectomy. 153 21

Patients with CPS often display recent memory deficits. Typically, general intelligence, perceptual skills, language, remote memory, and primary memory are all normal. However, the ability to learn new combinations of cognitively complex material is deficient. This deficit may be specific for verbal material (e.g., as a difficulty with learning to recall a response word given an unrelated cue word), for nonverbal material (e.g., as a difficulty in drawing a complex figure from memory), or for both verbal and nonverbal material. Because these characteristics are typical of memory deficits after MTL damage, it is reasonable to suspect that these deficits in patients with epilepsy also reflect MTL damage. In many cases, MTL damage is apparent from neuroimaging studies, whereas seizure semiology suggests MTL onset. In these patients, the same pathology might be the cause of both the ictus and memory deficits. In other cases, memory impairment appears to be secondary to seizures. This suggestion is supported by cases where prolonged complex partial status resulted in a permanent global amnesia. Cases with shorter-lasting memory deficits were also presented. Neuropsychological testing revealed specific recent-memory deficits that cleared 2 weeks after a flurry of CPS and 24 hr after a single seizure. Depth recordings have demonstrated that MTL electrographic seizures can occur without subjective manifestations. When these are evoked by local electrical stimulation, a profound inability to learn new material may be observed during the afterdischarge. Similarly, artificially induced MTL spike-and-wave complexes interfere with the memory for simultaneously presented complex visual scenes. Recent evidence suggests that all of the above phenomena may reflect the engagement by epileptiform processes of the association-cortex (AC)-MTL circuits used in normal human memory. In recent memory tasks, cognitive evoked-potential components N4 and P3 are generated in the MTL and to a lesser degree in related AC regions. The N4/P3 are strongly modulated by familiarity in recent memory. This modulation is eliminated by anterior temporal lobectomy. The typical slow wave following spontaneous MTL interictal spikes has the same MTL voltage topography, and thus probably similar synaptic generators, as the cognitive P3 potential. Furthermore, MTL spike-and-wave complexes can be evoked in recent memory tasks at a fixed latency equal to that of the N4.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Memory dysfunction in epilepsy patients as a derangement of normal physiology. 200 17

Male Wistar rats were subjected to pilocarpine-induced status epilepticus and allowed to recover. After reaching the chronic state with spontaneous seizures they were tested in an 8-arm radial maze. During learning trials, epileptic rats made significantly more errors than controls. Even in the last trials epileptic rats did not improve their performance, indicating severe learning disability. These results suggest that spontaneous seizures after pilocarpine-induced status epilepticus are a useful model for studying the learning and memory impairment detected in some cases of symptomatic epilepsy.
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PMID:Learning impairment in chronic epileptic rats following pilocarpine-induced status epilepticus. 210 Oct 94

Domoic acid (Dom), a rigid analog of the excitotoxic amino acids, glutamate and kainic acid, is believed to be the mussel neurotoxin responsible for a recent food poisoning incident in Canada that killed some people and left others with memory impairment. Since the literature contains very little information pertaining to Dom excitotoxicity, we have systematically evaluated the neuroexcitatory properties of Dom in vitro (cultured hippocampal neurons) and its neurotoxic properties both in vitro (chick embryo retina) and in vivo (adult rat). In the in vitro experiments, the properties of Dom were compared with those of kainic acid, N-methyl-D-aspartate (NMDA) and quisqualate, each of which is a prototypic agonist at a different subtype of glutamate receptor. Currents induced in hippocampal neurons by Dom and kainic acid were identical and displayed a linear current/voltage relationship (in contrast to NMDA currents) and were nondesensitizing (in contrast to quisqualate currents). Dom currents were not blocked by NMDA antagonists but were blocked by CNQX, an antagonist of non-NMDA receptors. In the chick embryo retina, Dom induced a lesion pattern having the same distinctive characteristics as a kainic acid lesion which differs from that induced by either NMDA or quisqualate, and the Dom lesion was blocked by CNQX but not by NMDA antagonists. Subcutaneous administration of Dom (2.5-3 mg/kg) to adult rats resulted in an acute seizure-brain damage syndrome almost identical to that induced in rats by KA (12 mg/kg) and having important features analogous to the neurotoxic syndrome observed in the human food poison victims.
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PMID:Domoic acid: a dementia-inducing excitotoxic food poison with kainic acid receptor specificity. 217 Jan 63

Thirty-five patients with medically refractory epilepsy localized to the temporal lobe (18 left, 17 right) completed the verbal Selective Reminding Test before surgery. Verbal memory impairments existed before surgery regardless of the lateralization of the seizure focus, but patients with left temporal seizure foci were significantly more impaired. After surgical removal of the mesial temporal lobe structures, 2 blinded observers established volumetric cell densities for hippocampal subfields CA1, CA2, CA3, the hilar area, and the granule cell layer of the area dentata. Statistically significant correlations existed between presurgical memory impairment and cell counts (in CA3 and the hilar area, only) for patients with left temporal seizure foci. These findings support the hippocampal model of memory and complement prior research documenting the memory impairments present after surgical removal of the mesial temporal structures.
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PMID:Verbal memory impairment correlates with hippocampal pyramidal cell density. 223 24

A retrospective review of colloid cysts diagnosed from 1974 to 1986 emphasizes the presenting symptoms of these lesions, their surgical management, and the contribution of modern imaging techniques to their diagnosis and therapy. In this 12-year period, 84 patients (45 men and 39 women) had a colloid cyst diagnosed. The patients' mean age was 46 years (range, 7-82 years). Surgery was performed in 55 patients, 7 of whom had undergone prior surgery elsewhere. The surgical approaches used were transfrontal-transventricular, transcallosal, computer-assisted stereotactic aspiration and resection by stereotactic craniotomy, and shunting of cerebrospinal fluid without removal of the lesion. There was no operative mortality, but complications occurred in 15 patients (27%). Preoperative imaging showed hydrocephalus in 93% of the patients: severe in 43%, moderate in 36%, and mild in 14%. In the surgically treated group, the most common presenting symptoms were headache, change in mental status, ataxia, nausea and vomiting, visual disturbance, emotional lability/inappropriate affect, depersonalization, and hypersomnolence. Twenty-four patients for whom surgery was not recommended are being followed up closely. Most of these patients had normal ventricles. The symptoms in this group included headache, anxiety/nervousness, ataxia, memory impairment, visual disturbance, and seizures. Five autopsy cases of patients with colloid cysts were available during this period and were reviewed. Direct removal of colloid cysts can be accomplished with low morbidity and mortality, avoiding the frequent revisions and complications related to shunt procedures. There is a subgroup of colloid cysts that can be operated upon electively or followed up closely with serial imaging studies.
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PMID:Colloid cysts: experience with the management of 84 cases since the introduction of computed tomography. 271 77

We examined the relationship between memory performance and hippocampal damage in temporal lobe epileptics undergoing the intracarotid amobarbital sodium procedure (IAP). Overall memory performance in the course of IAP was correlated with seizure lateralization. The hemisphere of seizure focus had impaired IAP memory in 63% (19/30) of the patients. The IAP memory performance following perfusion of the hemisphere contralateral to severe hippocampal lesions was impaired in five of six patients. These patients also exhibited hypometabolism of the impaired temporal lobe as determined independently by positron emission tomography. The single patient with a severely damaged hippocampus who did not demonstrate IAP memory impairment with contralateral hemisphere injection did not exhibit perfusion of the ipsilateral posterior cerebral artery with amobarbital. Memory performance following intracarotid amobarbital injection contralateral to a less severely damaged hippocampus was impaired in 14 of 24 patients and was not related to extent of hippocampal damage, temporal lobe hypometabolism of labeled glucose, perfusion of the ipsilateral posterior cerebral artery, hemispheric language dominance, or order of injection. These results indicate that impaired memory performance during IAP may reflect severe hippocampal damage and/or epileptogenic abnormality.
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PMID:Memory following intracarotid amobarbital injection contralateral to hippocampal damage. 274 50

Eighteen uncontrolled epileptic patients had neuropsychological evaluation before and after partial or total corpus callosotomy. In patients with early-onset seizures and signs of severe unilateral CNS dysfunction, callosotomy produced no deficits and several improvements. All patients whose language-dominant hemisphere did not control their dominant hand had impairments in some aspect of speech and language function after callosotomy. In some patients, unilateral deterioration of motor function was observed, and was associated with mild to moderate dysfunction in the contralateral hemisphere (ie, memory impairment or preexisting hemiparesis). Postoperative deficits occurred with partial, as well as total, section.
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PMID:Corpus callosotomy for epilepsy. II. Neurologic and neuropsychological outcome. 333 59

This study analyzes the frontotemporal and nasopharyngeal spectral energy of an ECT-induced seizure, in order to investigate the origin of the final Phase III activity, which contains most of the seizure's energy. Data supports these findings: energy in the delta frequency band is responsible for the generation, propagation, and maintenance of Phase III of the ECT-induced seizure; the synchronous "delta-firing" depolarizations of Phase III are recurrently initiated by an ECT-induced "generator" process; higher magnitudes of energy are generated centrally than are generated laterally during Phase III; and the lessened memory impairment associated with nondominant unilateral ECT is attributable to the markedly lower peak and total energies observed in the unstimulated temporal lobe.
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PMID:The electroencephalographic pattern during electroconvulsive therapy. III. Analysis of frontotemporal and nasopharyngeal spectral energy. 373 98


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