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

Recent developments of benzodiazepine receptor imaging (123I-Iomazenil SPECT and 11C-Flumazenil PET) in neuropsychiatric disorders were reviewed. In focal epilepsy, a number of previous studies have reported a decreased benzodiazepine receptor binding in epileptic foci and greater sensitivity compared to regional cerebral blood flow imaging, especially for diagnosis of medial temporal lobe epilepsy. These findings indicate clinical validity of benzodiazepine receptor imaging in focal epilepsy and may be related to the "disinhibition mechanism" in GABA/benzodiazepine systems underlying epilepsy. In panic disorder, abnormal benzodiazepine receptor bindings are recently demonstrated in the temporal, parietal or frontal cortex. Further studies would clarify the "benzodiazepine dysfunction hypothesis" in panic disorder.
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PMID:[Benzodiazepine receptor imaging in the brain: recent developments and clinical validity]. 1039 Sep 53

The aim of our work was to identify clinical and electroencephalographic factors that are statistically correlated to 99mTc HMPAO hypofixation in cryptogenic temporal lobe epilepsy. We selected a homogeneous group of patients (28 males and 17 females) affected by temporal lobe epilepsy and having normal results on computed tomography and magnetic resonance imaging. Patients were classified according to semeiological characteristics of the seizures, presence or absence of spikes on electroencephalography (EEG), age at onset, illness duration, and drug resistance. The presence of focal interictal spikes on EEG was statistically correlated to 99mTc HMPAO temporal hypofixation (p = 0.04). The other electroclinical factors considered in this series did not play an important role in modifying radiopharmaceutical fixation in focal epilepsy in interictal phase. We speculate that a possible explanation for focal radiopharmaceutical hypofixation, in addition to hypoperfusion, is an increased permeability of the blood-brain barrier (due to perivascular inflammation or other causes) which can be responsible for 99mTc HMPAO escape with a resultant hypofixation.
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PMID:Cryptogenic temporal lobe epilepsy. semi-quantitative interictal 99mTc HMPAO SPECT: statistical correlation with clinical data and EEG. 1055 10

Spontaneous seizures are the hallmark of human epilepsy but they do not occur in most of the epilepsy models that are used to investigate the mechanisms of epilepsy or to test new antiepileptic compounds. This study was designed to develop a new focal epilepsy model that mimics different aspects of human temporal lobe epilepsy (TLE), including the occurrence of spontaneous seizures. Self-sustained status epilepticus (SSSE) lasting for 6-20 h was induced by a 20-30 min stimulation of the lateral nucleus of the amygdala (100 ms train of 1 ms, 60 Hz bipolar pulses, 400 microA, every 0.5 s). Stimulated rats (n = 16) were monitored with a video-EEG recording system every other day (24 h/day) for 6 months, and every other video-EEG recording was analyzed. Spontaneous epileptic seizures (total number 3698) were detected in 13 of the 15 animals (88%) after a latency period of 6 to 85 days (median 33 days). Four animals (31%) had frequent (697-1317) seizures and 9 animals (69%) had occasional seizures (1-107) during the 6-months follow-up period. Fifty-seven percent of the seizures occurred during daytime (lights on 07:00-19:00 h). At the end of the follow-up period, epileptic animals demonstrated impaired spatial memory in the Morris water-maze. Histologic analysis indicated neuronal loss in the amygdala, hippocampus, and surrounding cortical areas, and mossy fiber sprouting in the dentate gyrus. The present data indicate that focal stimulation of the amygdala initiates a cascade of events that lead to the development of spontaneous seizures in rats. This model provides a new tool to better mimic different aspects of human TLE for investigation of the pathogenesis of TLE or the effects of new antiepileptic compounds on status epilepticus, epileptogenesis, and spontaneous seizures.
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PMID:A new model of chronic temporal lobe epilepsy induced by electrical stimulation of the amygdala in rat. 1064 46

Depression is a frequent psychiatric symptom in epilepsy and has been related to epilepsy of temporal origin, especially of left-sided foci. No study differentiated the precise localization of the epileptogenic lesion within the temporal lobe. Regarding this issue, we evaluated depression assessed by the Beck Depression Inventory in 60 patients with temporal lobe epilepsy, with particular consideration of morphological abnormalities within the temporal lobe (mesial temporal sclerosis (MTS) versus neocortical lesions) and lateralization of the lesion. Multivariate analyses indicated significant higher depression scores in MTS independent of the lateralization of the lesion. Depression was a good indicator for MTS but not vice versa. Hence, MTS can be discussed as a predisposing factor for the development of mood disorders in focal epilepsy.
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PMID:Depression in patients with temporal lobe epilepsy is related to mesial temporal sclerosis. 1075

Surgery has become an accepted treatment modality for carefully selected adults with intractable focal epilepsy. More recently, increasing numbers of pediatric patients with intractable epilepsy are also being referred for surgical consideration. Key elements of surgical candidacy include medically intractable focal epilepsy, a localized epileptogenic zone, and a low risk for new postoperative neurologic deficits. The most common etiologies of the epilepsies in pediatric surgical candidates are malformation of cortical development and low grade tumor but some patients with childhood onset temporal lobe epilepsy due to hippocampal sclerosis also present for early surgery. Based on results from several recent pediatric surgical series, the chance for favorable seizure outcome after surgery is not adversely affected by young age, with seizure-free postoperative outcome reported for 60% to 65% of infants, 59% to 67% of children, and 69% of adolescents, compared to 64% reported in a large, predominantly adult series. Some subgroups of patients have higher percentages of seizure-free outcome, including those with hippocampal sclerosis or low grade tumor. In addition to seizures, developmental issues are also a major concern in children with intractable epilepsy. Few quantitative data are available, but some anecdotal experience suggests that surgical relief of catastrophic epilepsy may result in resumption of developmental progression after surgery, although the rate of development often remains abnormal. In one series, best developmental outcomes were seen in patients with earliest surgery and highest level of preoperative development. For each patient, the timing of surgery must be carefully considered, based on a full assessment of the relative risks and benefits, derived from a detailed presurgical evaluation.
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PMID:Surgical treatment of epilepsy in pediatric patients. 1083 Mar 41

A clinically tonic seizure phase, immediately followed by psychomotor features (right hand dystonic posture, left hand and oral automatisms), was recorded by video and EEG, in a patient who had gliosis of the left temporal lobe and left hippocampal atrophy. Interictal epileptiform discharges were frequently seen in the left temporal area, and at the time of the tonic seizure phase, ictal spike discharges were continuously observed at the left posterior temporal area, which was recognized only by applying a high frequency filter (HFF) of 15 Hz to the digitally recorded EEG because EMG artifacts totally obscured the EEG with a HFF of 60 Hz. It is most likely that tonic seizure can occur in an adult patient with temporal lobe epilepsy, and it is speculated that an epileptogenic focus might activate a certain brain area which is regarded as a symptomatogenic zone for tonic seizures. If the tonic seizure phase is immediately followed by psychomotor features as seen in the present patient, the former could be due to focal epilepsy.
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PMID:Seizure with prominent tonic initial signs followed by psychomotor features: a case report clinically manifesting an unusual ictal evolution. 1093 43

The question we attempted to address in this chapter is: Do brief but recurrent seizures in early life alter the ontogeny of hippocampal networks in ways that produce epileptic circuits? Results from the tetanus toxin model suggest that this is likely the case. Following seizures in Postnatal Weeks 2 and 3, most adult rats have a focal epilepsy that arises from hippocampus. Recordings from hippocampal slices support this conclusion since they demonstrated the occurrence of spontaneous network discharges in normal artificial cerebrospinal fluid. Moreover, when GABA-A receptor-mediated synaptic transmission was suppressed, slices from adult epileptic rats produced prolonged electrographic seizures which are never observed in control rats. This suggests that hyperexcitable recurrent excitatory networks contribute to hippocampal seizures in this model. In light of this, anatomical results from biocytin-filled neurons were surprising. Results suggest that recurrent axon arbors neither sprout additional branches as a result of seizure activity nor maintain their exuberant branching patterns of early life. Thus, excessive connectivity cannot explain seizure generation. Axon arbors either remodel in normal ways or prune additional collaterals as a result of ongoing epileptiform discharging. At the same time that axon arbors remodel, the dendrites of these cells have decreased dendritic spine density, suggesting a partial deafferentation. While a complete understanding of the origins of spine loss requires further investigation, we hypothesize that this loss is a product of a partial deafferentation that occurs due to excessive and abnormal selection of synaptic connections. Network-induced heterosynaptic LTD of noncoincidentally active afferants may be one mechanism that leads to a loss of synapses. Moreover, competition among and selection between individual recurrent excitatory synapses may contribute to spine loss as well. The "winners" of this competition, the most potent and effective early-formed recurrent excitatory synapses, are likely key contributors to seizure generation in this model and possibly in humans with early-onset temporal lobe epilepsy.
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PMID:Neuronal activity and the establishment of normal and epileptic circuits during brain development. 1113 Sep 18

Magnetic resonance spectroscopy and functional magnetic resonance images are new non-invasive techniques which have the potential for localization of the epileptogenic focus in patients with refractory focal epilepsy, who are candidates for surgery. Determination of patterns of asymmetry of the N-acetyl-aspartic acid (NAA) between homologous regions of the temporal lobes, using magnetic resonance spectroscopy contributes to preoperative lateralization in patients with temporal lobe epilepsy. This technique may become a method for localization if its usefulness in the differentiation of mesial temporal lobe epilepsy from neocortical epilepsy is validated. Functional magnetic resonance images triggered by epileptiform discharges on the EEG, when combined with methods for localizing the source, permit the site of the epileptogenic focus to be found. This would particularly benefit patients with non-lesional extra-temporal epilepsy who are potential candidates for invasive recordings. The use of magnetic resonance spectroscopy and functional magnetic resonance images in the preoperative evaluation of patients with refractory focal epilepsy, especially if it is used together with the relevant clinical data and that from other structural and functional imaging techniques, will reduce invasive monitoring and increase the accessibility to surgical treatment for this condition.
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PMID:[Magnetic resonance spectroscopy and functional magnetic resonance images: non-invasive alternatives for identifying epileptogenic foci]. 1131 Feb 76

The authors studied the localizing or lateralizing value of painful epileptic auras in 25 patients with focal epilepsy. Painful auras were seen in 4.1% patients with focal epilepsy arising from temporal, frontal, perirolandic, or parieto-occipital regions. Abdominal pain was present in 5% of all abdominal auras in temporal lobe epilepsy and 50% of all abdominal auras in frontal lobe epilepsy. In perirolandic epilepsy, painful somatosensory auras were lateralized contralateral to the epileptic hemisphere but not consistently in temporal lobe epilepsy.
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PMID:Painful auras in focal epilepsy. 1152 83

The successful surgical treatment of medically refractory epilepsy is based on one of three different principles: (1) elimination of the epileptic focus, (2) interruption of the pathways of neural propagation, and (3) increasing the seizure threshold through cerebral lesions or electrical stimulation. Temporal lobe epilepsy, being the most common focal epilepsy, may ultimately require temporal lobectomy. This is a case report of a 36-year-old male with drug-resistant right mesial temporal lobe epilepsy who failed to obtain seizure control after stereotactic radiosurgery to the seizure focus. Complex-partial seizures occurred 6-7 times monthly, and consisted of a loss of awareness followed by involuntary movements of the right arm. EEG/CC TV monitoring indicated a right mesial temporal lobe focus, which was corroborated by decreased uptake in the right temporal lobe by FDG-PET and by MRI findings of right hippocampal sclerosis. Stereotactic radiosurgery was performed with a 4MV linac, utilizing three isocenters with collimator sizes of 10, 10, and 7 mm respectively. A dose of 1500 cGy (max dose 2535 cGy) was delivered in a single fraction to the patient's right amygdala and hippocampus. There were no acute complications. Following radiosurgery the patient's seizures were improved in both frequency and intensity for approximately 3 months. Antiepileptic medications were continued. Thereafter, seizures increased in both frequency and intensity, occurring 10-20 times monthly. At 1 year post radiosurgery, standard right temporal lobectomy including amygdalohippocampectomy was performed with subsequent resolution of complex-partial seizures. Histopathology of the resected temporal lobe revealed hippocampal cell loss and fibrillary astrocytosis, consistent with hippocampal sclerosis. No radiation-induced histopathologic changes were seen. We conclude that low-dose radiosurgery doses temporarily changed the intensity and character of seizure activity, but actually increased seizure activity long-term. If radiosurgery is to be an effective alternative to temporal lobectomy for medically intractable temporal lobe epilepsy, higher radiosurgery doses will be required. The toxicity and efficacy of higher-dose radiosurgery is currently under investigation.
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PMID:Low-dose stereotactic radiosurgery is inadequate for medically intractable mesial temporal lobe epilepsy: a case report. 1170 Oct


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