Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0014547 (focal epilepsy)
 1,627 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of carbamazepine (CBZ) on EEG background activity have been studied, at rest and during mental processes, in 18 epileptic patients suffering from focal epilepsy and starting antiepileptic treatment for the first time. The EEGs were recorded before and after CBZ therapy, at rest with eyes closed (EC), during blocking reaction (BR), fixation (FIX) and mental arithmetic (MA) tasks, and then evaluated by spectral analysis. All data underwent statistical evaluation utilizing the ANOVA and correlation coefficient. The following parameters were evaluated: mean absolute and relative power and mean frequency. The results have shown that CBZ induced a significant increase of slow activity at rest with EC, which was represented by delta potentials, and was correlated with CBZ plasma levels. In evaluating the different cortical activation patterns, a decrease of the alpha reactivity was noted during BR and FIX, while a significant increase of beta activity was observed during the performance of all tasks. The relationship between the increased beta power, possibly reflecting an increase of cognitive activity for processing information, and the lack of a significant decrease of alpha activity are discussed.
 ...
PMID:EEG changes induced by carbamazepine therapy at rest and during mental processes. 148 55

We have described the occurrence in freely moving gerbils of slow potential changes (SPC) in two different models of experimental epilepsy: 1) maximal electroshock and 2) bilateral epileptic foci induced by penicillin. SPC is considered a by-product of epileptiform activity in both models and correlates to the SPC which occurs during spreading depression. In the first model there develops a cortical SPC simultaneous with a depression of EEG activity, although there is no propagation of the wave. We suggest that a non-propagated multifocal depression (MD) occurs in the MES model. In the model of focal epilepsy, all requirements are fulfilled, and the SPC is characterized as the one which occurs during spreading depression propagating with an average velocity of 8 mm/min.
 ...
PMID:Cortical slow potential changes during convulsions induced by maximal electroshock or penicillin focus. 152 70

1. gamma-Aminobutyric acid (GABA) withdrawal syndrome (GWS) represents a particular model of focal epilepsy consecutive to the interruption of a chronic intracortical GABA infusion and is characterized by the appearance of focal epileptic electroencephalographic (EEG) discharges and localized clinical signs on withdrawal of GABA. Effects of Ca2+ channel blockers and N-methyl-D-aspartate (NMDA) antagonists were evaluated in living rats presenting a GWS after interruption of a 5-day GABA infusion into the somatomotor cortex and in neocortical slices obtained from such rats. Bursting properties and morphology of neurons were also analyzed in slices. 2. In living rats, the noncompetitive NMDA antagonist phencyclidine [1-(1-phenylcyclohexyl)piperidine] and the Ca2+ antagonist flunarizine [E-1 (bis(4fluorophenyl)methyl)-4(3phenyl2-propenyl)-piperazine] were administered systemically to two groups of rats. Rats in the first group (n = 12) were injected with the drug 30-60 min before discontinuation of the GABA infusion. In this case, phencyclidine (10 mg/kg ip) prevented the development of GWS (n = 5), whereas flunarizine (40 mg/kg ip) had no consistent effect on the GWS appearance and characteristics (n = 7). Rats in the second group (n = 12) were injected 60-90 min after GABA discontinuation, i.e., during a fully developed GWS. In that case, neither drug suppressed GWS. 3. Neuronal activities in the epileptic focus were studied in slices with conventional intracellular recording and stimulation techniques. From the 65 neurons recorded, 29 responded with EPSPs and paroxysmal depolarization shifts (PDSs) to white matter stimulation (synaptic bursting or SB cells). Nineteen other neurons presented, in addition to synaptically induced PDSs, bursts of action potentials (APs) induced by intracellular depolarizing current injection (intrinsic bursting or IB cells). The remaining 17 neurons presented no bursting properties to either synaptic stimulation or depolarizing current injection (nonbursting or NB cells). 4. The recorded neurons were located 0.7-1.2 mm distant from the lesion because of the penetration of the GABA infusion cannula. Intracellular injection of neurons (n = 4) with biocytin or Lucifer yellow revealed that both SB and IB neurons were large, spiny pyramidal neurons localized in layer V of the sensorimotor cortex. 5. Bath application of the selective antagonist of NMDA receptors DL-2amino-5phosphonovalerate or DL-2amino-7phosphonoheptanoate (10-50 microM) reversibly reduced the amplitude (by 25-50%) and the duration (by 20-25%) of PDSs in all cases (n = 17).(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Burst generation in neocortical neurons after GABA withdrawal in the rat. 153 60

Surgical management of uncontrolled focal epilepsy is most commonly carried out in young adults with good results, but there has been some doubt about the effectiveness of cortical resection in older individuals. We assessed the outcome of temporal lobectomy done after age 45 years in 20 patients with intractable epilepsy followed for more than 2 years after surgery. During a mean follow-up of 5 years, six patients (30%) were seizure-free following surgery and seven (35%) had greater than 90% reduction in seizure frequency. This compares with an outcome of 40% seizure-free and 44% with greater than 90% seizure reduction in 68 younger patients aged 17 to 45 years; the differences do not achieve statistical significance. The outcome was better for complex partial seizures than for secondarily generalized seizures. Complications were no greater than in the younger patients. The findings indicate that surgery is an effective treatment alternative for intractable temporal lobe epilepsy in older patients since two of three of these patients will obtain satisfactory seizure control.
 ...
PMID:Temporal lobectomy for intractable epilepsy in patients over age 45 years. 154 33

The waveform morphology of interictal spike activity associated with uncontrolled childhood focal epilepsy was quantified in 40 patients by a computer-based technique. The findings were then analyzed with respect to epileptic syndromes. Samples of spike activity from each patient were characterized by determination of average amplitude (A), duration (D), and sharpness (S). A single morphologic index, the composite spike parameter (CSP), was also derived from the basic spike parameters (CSP = A x D/S). The spikes of patients in the benign focal epilepsy category differed from those of patients in other syndromic categories (symptomatic, cryptogenic, and Landau-Kleffner). Specifically, they were higher in amplitude, longer in duration, less sharp, and had a higher CSP value. The pretreatment spike parameters did not differ significantly in patients who responded favorably to initial antiepileptic drug (AED) therapy as compared with those whose seizures were harder to control. The findings suggest that quantitative assessment of interictal spike morphology may help develop a more objective basis for classifying patients according to epileptic syndrome.
 ...
PMID:Spike morphology in childhood focal epilepsy: relationship to syndromic classification. 159 33

Resective surgery is an accepted treatment modality for medically intractable focal epilepsy in children as well as in adult. During the presurgical evaluation processes, intracranial neurophysiologic recording of epileptiform abnormalities have been used much more commonly in adults and older adolescents than in infants and children. However, as infants and children are increasingly referred for early surgery in many centres, it may be necessary to study complex cases in some children with invasive electrodes in order to plan a safe and effective resection. This article gives first an overview of the rationale and indications, with case illustrations, for using these techniques. This is followed by general discussions on individual electrodes and their use in infants and children.
 ...
PMID:Use of intracranial neurophysiologic recording techniques in the evaluation for epilepsy surgery in children. 162 Nov 15

Penfield's observations in the 1930s provided the first systematic evidence of changes in regional cerebral blood flow (rCBF) associated with focal seizures. Further studies in humans and animals confirmed increases in cerebral blood flow and metabolism during generalised seizures, but the interictal, ictal, and postictal changes in focal epilepsy have begun to be elucidated in the last decade with the advent of in vivo imaging techniques such as positron emission tomography (PET) and single photon emission computed tomography (SPECT) and, in the case of animal studies, of autoradiography. Most studies have been of temporal lobe epilepsy. Interictally, the characteristic finding has been reduced blood flow and/or metabolism in the affected temporal lobe, or more extensively in the ipsilateral hemisphere. The few studies to date of ictal or postictal changes have been of rCBF using SPECT. They show hyperperfusion of the whole temporal lobe ictally, hyperperfusion of the hippocampus, combined with hypoperfusion of lateral structures in the immediate postictal period. Later in the postictal period, hypoperfusion alone is seen. Studies of focal seizures in animals have shown hyperperfusion and hypermetabolism at the site of the focus often with widespread depression of both parameters in the ipsilateral neocortex. Limited studies of coupling between blood flow and metabolism in humans have suggested that flow during seizures is adequate for metabolic demand, although some animal studies have suggested localised areas of uncoupling. The results of modern in vivo imaging of ictal and postictal changes in blood flow and metabolism have correlated well with Penfield's observations, and these changes are now being used to help localise epileptic foci, allowing wider use of the surgical treatment he pioneered.
 ...
PMID:Epilepsy, cerebral blood flow, and cerebral metabolic rate. 162 38

A limited cortical resection including the rolandic fissure and the pre- and postcentral cortical regions was carried out in a patient suffering from epilepsia partialis continua resistant to antiepileptic drugs. The histological examination revealed several foci of very large neurons distributed with no laminar organization in the depth of the rolandic fissure and in the crown of the primary motor and primary somatosensory areas; these lesions were consistent with focal cortical dysplasia. In addition, decreased numbers of neurons, astrocytosis and proliferation of capillaries, compatible with chronic tissue necrosis, were found in the inferior regions of the banks of the rolandic fissure. Subpopulations of local-circuit neurons were examined with parvalbumin, calbindin D-28k and somatostatin immunocytochemistry. Focal areas of cortical dysplasia contained abnormal immunoreactive neurons. Huge parvalbumin-immunoreactive cells were distributed at random and resembled axo-axonic (chandelier) and basket neurons. Abnormal calbindin D-28k-immunoreactive cells were reminiscent of double-bouquet neurons and multipolar cells. Very large somatostatin-immunoreactive cells were seldom observed in the dysplastic foci. On the other hand, areas of tissue necrosis displayed massive reduction of immunoreactive cells and fibers. Abnormalities in the morphology and distribution of local-circuit (inhibitory) neurons observed here for the first time in focal cortical dysplasia may have a pivotal role in the appearance and prolongation of electrical discharges and continuous motor signs in human focal epilepsy.
 ...
PMID:Abnormal local-circuit neurons in epilepsia partialis continua associated with focal cortical dysplasia. 163 80

A patient developed distinct episodes of major depressive illness, schizophreniform psychoses and mania as well as focal epilepsy following head injury. Head injury may be directly causative in the development of affective psychoses, in this case secondary bipolar (mixed) disorder.
 ...
PMID:Bipolar affective disorder following head injury. 167 76

In order to localize epileptogenic electrophysiological sources, a multichannel MEG system was used in 3 patients with partial epilepsy during presurgical evaluation. MEG and EEG (including scalp, sphenoidal and intracranial foramen ovale electrodes) were recorded simultaneously during a period of intensive video-EEG monitoring in order to observe single spontaneous spikes. In addition to MRI, SPECT and PET investigations were performed. Electrical activity subsequent to the activity of the epileptic focus could be localized by the MEG after noise reduction using a temporal correlation technique. Simultaneous registration of the magnetic field and the electrical field showed that the source of the primary focal epileptic activity (first period during the total spike wave complex where a dipolar magnetic field pattern is found) is localized in neocortical lateral regions, whereas another focal epileptic activity in a later phase of propagation occurs in temporal mesial regions. In 1 patient (case 1) the primary focal epileptic activity was localized in the surrounding neocortical tissue of an angioma and the middle and inferior temporal gyrus. The second phase of propagation is localized in temporo-basal-mesial regions, including para- and hippocampal structures. The latest center of activity occurred in posterior parts of the gyrus cinguli. In 2 other patients, the primary focal epileptogenic activity was localized at the insula and also spread into temporal basal mesial regions. A multi-modal approach to research of focal epilepsy, combining metabolic, electrical potential, magnetoencephalographic and morphological data, recorded by non-invasive techniques, offers new perspectives for the detection of involved brain regions. The 3-D and time-resolved localization of focal epileptic activity, correlated with the individual anatomy of the human brain, may improve the determination of neuronal populations involved in the individual epileptogenic process, especially in the interaction between temporal or extratemporal neocortex and limbic system.
 ...
PMID:The neocortico to mesio-basal limbic propagation of focal epileptic activity during the spike-wave complex. 171 45


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>