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Query: UMLS:C0014547 (focal epilepsy)
 1,627 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Epilepsy surgery in childhood can now be more readily considered as a result of enhanced presurgical investigative techniques and safer neurosurgical practice. As in adults, surgery available may be resective (focal resection or hemispherectomy) or functional. The most common procedures are temporal lobectomy and hemispherectomy, with malformative lesions and developmental tumours the next common pathology. The timing of surgery requires careful consideration, and the definition of drug resistance given specific thought in the young child. Presurgical evaluation should be noninvasive where possible, and should include optimised MRI, including 3D data set and video EEG telemetry to document seizures. Detection of temporal lobe abnormalities in temporal lobe epilepsy with MR may be enhanced using quantitative and semiquantitative techniques. Ictal and interictal SPECT may be useful in providing information about the seizure onset zone, if reviewed in conjunction with MR data and video-EEG. Interictal PET is more likely to demonstrate abnormalities relating to structural defects, but may be particularly useful in infants where incomplete myelination may restrict structural information provided by MRI. Neuropsychology testing plays a major role by the determination of verbal and nonverbal function in older children, and in the determination of cerebral dominance. Functional MRI for determination of language or motor cortex may enhance such evaluation, although it is limited to older unsedated children at present. Although the aims of the presurgical evaluation remain similar to adult practice, the range of children presenting is wide, and the aims and likely outcome of surgery require careful evaluation with the family. This aside, the benefits of seizure elimination or reduction in drug-resistant focal epilepsy prior to adolescence, as well as in certain early catastrophic epilepsies of childhood, remain self apparent.
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PMID:Epilepsy surgery in childhood. 1206 8

Focal epilepsy secondary esp to scar or injured cortical tissue forms a source of constant depolarisation site with or without emitting negative charges (current of injury) into the surrounding area. This focal site is localised by EEG, MRI and if required, by PET and/or SPECT studies. The author postulates to implant electrical source of opposite charge overlying the focal site to nullify the constant depolarisation site (electrical resection) or short-circuit the current of injury to an inert site to alleviate focal epileptic attack. Preliminary trials in the form of scalp application of positivity have markedly improved EEG picture in terms of occurrence of epileptiform activity.
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PMID:Electrical resection: new concept in management of focal epilepsy. 1237 70

In patients with focal epilepsy, focal neurological dysfunction can occur due to status epilepticus and also as a post-ictal phenomenon. Bulbar dysfunction as evident by drooling, dysarthria, swallowing difficulties, and palatal-glossalpharyngeal weakness has been reported in conjunction with epilepsy. This is non-progressive and is correlated in its severity with the frequency of seizures. Accompanying EEG discharges are often localized to rolandic areas that cortically represent oral movements and salivation. We report a 6-year-old male and a 6 1/2-year-old female with progressive bulbar dysfunction resulting from epilepsy. Ictal EEGs in patient 1 did not confirm a diagnosis of epilepsy. With no evidence of a cortical or brainstem focus from EEG or MRI, it is very difficult to explain the mechanism of bulbar dysfunction. The complete restoration of bulbar function after treatment with antiepileptic drugs demonstrates the need to consider epilepsy in similar clinical situations.
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PMID:Epilepsy with reversible bulbar dysfunction. 1241 18

In 20-30% of potential surgical candidates with refractory focal epilepsy, standard MRI does not identify the cause. gamma-Aminobutyric acid (GABA) is the principal inhibitory neurotransmitter in the brain. [(11)C]Flumazenil (FMZ) PET images most subtypes of GABA(A) receptors, present on most neurons. We investigated [(11)C]FMZ binding in grey and white matter in 16 normal controls and in 44 patients with refractory neocortical focal epilepsy and normal optimal MRI. Fourteen patients had unilateral frontal lobe epilepsy, five occipital lobe epilepsy (OLE), six parietal lobe epilepsy (PLE) and 19 neocortical epilepsy that was not clearly lobar. Parametric images of FMZ volume of distribution (FMZ-V(d)) were computed. Statistical parametric mapping (SPM99) with explicit masking, including the white matter, was used to analyse individual patients and groups. Thirty-three of the 44 patients showed focal abnormal FMZ-V(d); increases in 16, decreases in eight, and both increases and decreases in nine. In seven patients, the increases in FMZ binding were periventricular, in locations normally seen in periventricular nodular heterotopia on MRI. There were frontal and parietal increases in FMZ binding in grey and white matter in the PLE group and decreases in the cingulate gyrus in the OLE group. FMZ binding increases, particularly periventricular increases, were a prominent feature of MRI-negative focal epilepsies and may represent neuronal migration disturbances.
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PMID:Grey and white matter flumazenil binding in neocortical epilepsy with normal MRI. A PET study of 44 patients. 1276 53

Combining electroencephalogram (EEG) and functional MRI (fMRI) allows localization of brain regions activated as a result of epileptic spikes. The statistical analysis of fMRI data usually includes a standard model of the hemodynamic response function (HRF) but it is not known how well this fits the actual HRF of epileptic spikes. The objective of this exploratory study was to compare the activated areas and t-statistical scores obtained with a standard HRF to those obtained with a patient-specific HRF. Eight patients with focal epilepsy were studied. We obtained an estimate of the patient-specific HRFs for each patient at the local maximum of activation in the standard HRF analysis. The activated areas obtained with the patient-specific HRFs were larger or similar to the originally activated areas. Additional activated areas were seen in five patients, and most were compatible with the EEG and anatomical MRI localization of epileptogenic and lesional regions. Using patient-specific HRFs brings increased sensitivity to the analysis of epileptic spikes by EEG-fMRI.
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PMID:Using patient-specific hemodynamic response functions in combined EEG-fMRI studies in epilepsy. 1456 85

Among 70 patients with intractable focal epilepsy and no specific lesion, as determined by both MRI (magnetic resonance imaging) and histopathology, outcome after resective surgery was polarized: 26 (37%) became seizure free (SF), and 27 (39%) were not helped. Eighteen (42%) of 43 standard temporal resections rendered patients SF, somewhat more than eight (30%) of 27 other procedures. To seek reliable prognostic factors, the subsequent correlative data compared features of the 26 SF patients with those of the 27 not helped. Although ictal semiology guided the site of surgical resection, it and other aspects of seizure and neurologic history failed to predict surgical outcome. However, two aspects of preoperative scalp EEGs correlated with SF outcomes: (a) among 25 patients in whom >50% of clinical seizures arose from the later resected lobe and no other origins, 18 (72%) became SF compared with seven (28%) of 25 with other ictal profiles; (b) 13 (93%) of 14 temporal lobe patients whose interictal and ictal EEGs lacked features indicative of multifocal epileptogenesis became SF compared with five (33%) of 15 with such components. The considered need for subdural (SD) EEG reduced SF outcome from 18 (90%) of 20 patients without SD to eight (24%) of 33 with SD; this likely reflected an insufficient congruity of ictal semiology and interictal and ictal scalp EEG for localizing epileptogenesis. Within this SD group, >50% of clinical seizure origins from a later resected lobe increased SF outcome somewhat: from two (14%) of 14 without this attribute to six (40%) of 15 with it; 100% of such origins increased SF outcome from two (12%) of 16 to six (46%) of 13.
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PMID:Indices of resective surgery effectiveness for intractable nonlesional focal epilepsy. 1469 7

We report on the simultaneous and continuous acquisition of EEG and functional MRI data in a patient with a left hemiparesis and focal epilepsy secondary to malformation of cortical development in the right hemisphere. EEG-triggered fMRI localization was previously demonstrated in this patient. In the experiments reported here, 322 spikes maximum at electrode C4 and 126 focal slow waves were identified offline. A hierarchy of models was explored in order to assess the relative contributions of each type of EEG event. Modeling the BOLD response to C4 spikes alone showed an area of activation within the large malformation, adjacent to the area of infolding cortex. However, also modeling slow-waves gave rise to a broader and stronger activation, suggesting that the generators overlap. Motor mapping of the right hand showed activation in the left sensorimotor cortex; left-hand tapping led to a more diffuse area of activation, displaced superiorly into the superior frontal gyrus, and a small area of activation within the lesion. In conclusion, continuous EEG-fMRI is useful to compare the functional mapping of epileptiform activity and eloquent cortices in individual patients.
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PMID:Mapping of spikes, slow waves, and motor tasks in a patient with malformation of cortical development using simultaneous EEG and fMRI. 1472 24

The study examined performance on a dichotic listening test in children with focal epilepsy. The aim of the study was to explore how factors related to brain pathology would affect ear advantage. The effects of lateralization of epileptogenic area, size and localization of structural abnormality on MRI findings, and seizure characteristics were studied. Children treated for focal epileptic seizures took part in the study (N = 35). The dichotic test consisted of pairs of words, nonwords, syllables and vowels. Results demonstrated that large congenital structural abnormality in the left hemisphere altered ear advantage whereas smaller abnormality and right-hemisphere abnormality did not. Further, epileptic seizures of left-hemisphere origin that had started at an early age affected ear advantage whereas seizure frequency at the time of the assessment did not. Children with early onset of seizures of right-hemisphere origin had a strong right-ear advantage. The total score did not differ between the groups. There was a strong negative correlation between the scores for the right-ear and the left-ear. The findings were interpreted to indicate altered functional dominance for perception of auditory, linguistic stimuli following early left-hemisphere pathology rather than unilateral functional suppression.
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PMID:Dichotic listening in children with focal epilepsy: effects of structural brain abnormality and seizure characteristics. 1497 96

0.5-1% of the population suffers from epilepsy, while another 5% undergoes diagnostic evaluations due to the possibility of epilepsy. In the case of suspected epileptic seizures we face the following questions: Is it an epileptic seizure? The main and most frequent differential-diagnostic problems are the psychogenic non-epileptic seizures ("pseudo-seizures") and the convulsive syncope, which is often caused by heart disorders. Is it epilepsy? After an unprovoked seizure, the information on recurrence risk is an important question. The reoccurrence is more possible if a known etiological factor is present or the EEG shows epileptiform discharges. After an isolated epileptic seizure, the EEG is specific to epilepsy in 30-50% of cases. The EEG should take place within 24 hours postictally. If the EEG shows no epileptiform potentials, a sleep-EEG is required. What is the cause of seizures? Hippocampal sclerosis, benign tumors, and malformations of the cortical development are the most frequent causes of the focal epilepsy. Three potentially life-threatening conditions may cause chronic epilepsy: vascular malformations, tumors, and neuroinfections. The diagnosis in theses cases can usually be achieved by MRI, therefore, MRI is obligatory in all epilepsies starting in adulthood. The presence of epileptogenic lesion has a prognostic significance in treatment. If the MRI shows a circumscribed lesion then the pharmacological treatment will likely to be unsuccessful, while surgery may result in seizure freedom. The new and quantitative MRI techniques, such as volumetry, T2-relaxometry, MR-spectroscopy, and functional MRI play a growing role in the epilepsy diagnosis.
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PMID:[Diagnosis of epilepsy]. 1526 91

Focal epilepsy can present with a rapidly progressing course of intractable epilepsy in children. We present a typical example of such a patient with focal seizures due to a frontal lobe cortical lesion of developmental origin. MRI and SPECT revealed abnormalities in the right frontal lobe. Surgical resection resulted in excellent outcome.
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PMID:Catastrophic focal epilepsy. 1528 50


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