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Temporal Lobe Epilepsy (temporal + lobe_epilepsy)
Kinds of Temporal Lobe Epilepsy Terms modified by Temporal Lobe Epilepsy Selected AbstractsMolecular Neuropathology of Temporal Lobe Epilepsy: Complementary Approaches in Animal Models and Human Disease TissueEPILEPSIA, Issue 2007Michael Majores Summary:, Patients with temporal lobe epilepsies (TLE) frequently develop pharmacoresistance to antiepileptic treatment. In individuals with drug-refractory TLE, neurosurgical removal of the epileptogenic focus provides a therapy option with high potential for seizure control. Biopsy specimens from TLE patients constitute unique tissue resources to gain insights in neuropathological and molecular alterations involved in human TLE. Compared to human tissue specimens in most neurological diseases, where only autopsy material is available, the bioptic tissue samples from pharmacoresistant TLE patients open rather exceptional preconditions for molecular biological, electrophysiological as well as biochemical experimental approaches in human brain tissue, which cannot be carried out in postmortem material. Pathological changes in human TLE tissue are multiple and relate to structural and cellular reorganization of the hippocampal formation, selective neurodegeneration, and acquired changes of expression and distribution of neurotransmitter receptors and ion channels, underlying modified neuronal excitability. Nevertheless, human TLE tissue specimens have some limitations. For obvious reasons, human TLE tissue samples are only available from advanced, drug-resistant stages of the disease. However, in many patients, a transient episode of status epilepticus (SE) or febrile seizures in childhood can induce multiple structural and functional alterations that after a latency period result in a chronic epileptic condition. This latency period, also referred to as epileptogenesis, cannot be studied in human TLE specimens. TLE animal models may be particularly helpful in order to shed characterize new molecular pathomechanisms related to epileptogenesis and open novel therapeutic strategies for TLE. Here, we will discuss experimental approaches to unravel molecular,neuropathological aspects of TLE and highlight characteristics and potential of molecular studies in human and/or experimental TLE. [source] Cerebral Cortical Gyrification: A Preliminary Investigation in Temporal Lobe EpilepsyEPILEPSIA, Issue 2 2007Lisa Ronan Summary:,Purpose: To introduce a measure of global cortical folding in epilepsy by using stereology. Subtle developmental abnormalities associated with temporal lobe epilepsy may encompass brain morphologic changes such as an aberrant degree of cortical folding. Methods: Stereologic methods of volume and surface-area estimation were applied to in vivo MR brain-image data of a cohort of 20 temporal lobe epilepsy (TLE) patients (10 men, 10 women), and 20 neurologically normal controls (10 men, 10 women). Indices of cerebral gyrification and cerebral atrophy were generated. The impact of side of seizure onset, age at onset, history of febrile seizures, presence or absence of lesions, and presence or absence of secondarily generalized seizures on cerebral gyrification was assessed. Results: Although no significant group mean difference was found in the degree of cerebral gyrification between patients and controls, five of 10 of male patients had an abnormal gyrification when compared with male controls. One female patient had a significant change in gyrification compared with female controls. In general, patients with TLE demonstrated a significant degree of global cerebral atrophy compared with controls. Clinical factors were not demonstrated to affect significantly any of the quantitative parameters. Conclusions: The results of this study suggest that an aberrant degree of global cerebral gyrification may occur in certain clinical groups of TLE patients. These findings have implications for general theories of developmental susceptibility in TLE. [source] Voxel-based T2 Relaxation Rate Measurements in Temporal Lobe Epilepsy (TLE) with and without Mesial Temporal SclerosisEPILEPSIA, Issue 2 2007Susanne G. Mueller Summary:,Introduction: Quantitative measurements of T2 relaxation in the hippocampus for focus lateralization in mesial temporal lobe epilepsy (mTLE) are well established. Less is known to what degree such relaxation abnormalities also affect regions beyond the ipsilateral hippocampus. Therefore, the aim of this study was to characterize extent and distribution pattern of extrahippocampal relaxation abnormalities in TLE with (TLE-MTS) and without MRI evidence of mesial-temporal sclerosis (TLE-no). Methods: Double spin echo images (TE1/2: 20/80 ms) acquired in 24 TLE-MTS and 18 TLE-no were used to calculate relaxation rate maps. These maps were analyzed by SPM2 and by selecting regions of interest (ROI) in the hippocampus and several extrahippocampal brain regions. Results: In TLE-MTS, the results of the SPM and ROI analysis were in good agreement and showed the most severe relaxation rate decreases in the ipsilateral hippocampus but also in other ipsilateral temporal regions, orbitofrontal, and parietal regions and to a lesser degree in contralateral frontal regions. The relaxation rate decreases in TLE-no were confined to small regions in the ipsilateral anterior inferior and medial temporal lobe in the SPM analysis while ROI analysis showed additional regions in the ipsilateral hippocampus, amygdala, and anterior cingulate. Conclusion: TLE-MTS showed extensive, widespread but predominantly ipsilateral temporal and also extratemporal T2 relaxation rate decreases. In contrast, the findings of the SPM and ROI analyses in TLE-no suggested that if relaxation rate decreases are present, they are less uniform and generally milder than in TLE-MTS. This further supports the hypothesis that TLE-no is a distinct clinicopathological entity from TLE-MTS and probably heterogeneous in itself. [source] The Localization and Lateralization of Memory Deficits in Children with Temporal Lobe EpilepsyEPILEPSIA, Issue 1 2007Linda M. Gonzalez Summary:,Purpose: It is often reported that children with temporal lobe epilepsy (TLE) experience nonlateralized memory impairments. However, many of these studies have been exploratory and not based on memory theory. Further, differences between mesial and lateral subgroups have not been adequately examined. This study aimed to discern more specific patterns of memory impairment in children with TLE. Methods: Forty-three children (5,16 years) with lesional TLE participated. Subjects were categorized in terms of lesion laterality (left, n = 21; right, n = 22) and intratemporal location (mesial, n = 31; lateral, n = 12). Verbal and nonverbal memory tasks were administered that reflected associative, allocentric and recognition paradigms. Results: Facial recognition was poorer in right TLE (p = 0.03). There were no differences between left and right groups on any other memory task, even when comparisons were restricted to cases with mesial involvement. Irrespective of laterality, clear differences were observed between mesial and lateral lesion subgroups (arbitrary associative learning, p = 0.01; complex figure recall, p = 0.03). The lateral lesion subgroup displayed intact memory function relative to normative standards. Conclusions: Memory is more frequently impaired in children with mesial as opposed to lateral TLE. Tasks with an associative component discriminated between these subgroups, supporting an associative model of hippocampal function. With the exception of facial recognition, memory deficits were not lateralized. Therefore, the nature of memory impairment experienced by children with TLE cannot be extrapolated from adult models. [source] Decreased Dopamine D2/D3-Receptor Binding in Temporal Lobe Epilepsy: An [18F]Fallypride PET StudyEPILEPSIA, Issue 8 2006Konrad J. Werhahn Summary:,Purpose: Although animal data are suggestive, evidence for an alteration of the extrastriatal dopaminergic system in human focal epilepsy is missing. Methods: To quantify D2/D3-receptor density, we studied seven patients with temporal lobe epilepsy (TLE) and nine age-matched controls with positron emission tomography (PET) by using the high-affinity dopamine D2/D3-receptor ligand [18F]Fallypride ([18F]FP) suitable for imaging extrastriatal binding. TLE was defined by interictal and ictal video-EEG, magnetic resonance imaging (MRI), and [18F]fluorodeoxyglucose ([18F]FDG)-PET and was due to hippocampal sclerosis (HS), based on histology in all patients. Primary analysis was based on regions of interest (ROIs) defined on individual MRIs. For each patient, binding potential (BP) was calculated by using the simplified reference tissue model, and the epileptogenic was compared with the unaffected hemisphere in each ROI. To confirm the results, an additional voxel-based group analysis was performed by using statistical parametric mapping. Results: Compared with controls, [18F]FP BP was significantly decreased in the epileptogenic temporal lobe in all patients. On ROI analysis, this reduction was evident in areas surrounding the seizure-onset zone at the pole (,34.2%) and lateral aspects (,32.9%) of the temporal lobe. Although the hippocampus [18F]FDG uptake (,8.1%) and hippocampal MR volume (,35.1%) were significantly reduced, no significant decrease of [18F]FP BP was found. Reduction of [18F]FP BP did not correlate with hippocampal atrophy. Conclusions: D2/D3-receptor binding is reduced at the pole and in lateral aspects of the epileptogenic temporal lobe in patients with mesial TLE and HS. This area might correspond to "the irritative zone," indicating that D2/D3 receptors might play a specific role in the pathophysiology of mesial TLE. [source] Socrates and Temporal Lobe Epilepsy: A Pathographical Diagnosis 2400 Years LaterEPILEPSIA, Issue 6 2006Article first published online: 7 JUN 200 No abstract is available for this article. [source] Familial Temporal Lobe Epilepsy with Auditory FeaturesEPILEPSIA, Issue 2005Fernando Cendes No abstract is available for this article. [source] Prognostic Factors for the Surgery for Mesial Temporal Lobe Epilepsy: Longitudinal AnalysisEPILEPSIA, Issue 8 2005Sang-Wuk Jeong Summary:,Purpose: Determining long-term prognostic factors of surgery for mesial temporal lobe epilepsy (MTLE) is important for identifying ideal candidates and predicting the prognosis for individual patients. We tried to identify the prognostic factors of anterior temporal lobectomy (ATL) for MTLE with longitudinal multivariate analysis. Methods: Two hundred twenty-seven patients with MTLE were included in this study. The primary outcome variable was patient status 1,5 years after surgery: seizure free, or not. Clinical characteristics and recent diagnostic modalities were considered as prognostic factors. Univariate and standard multiple logistic-regression analysis for outcome at 1 and 5 years after surgery and the generalized estimation equation (GEE) model for longitudinal multiple logistic regression of the 5-year follow-up period were used. Results: The seizure-free rate at 1 year was 81.1% and decreased to 75.2% at 5 years after surgery. By the univariate or standard multiple logistic-regression analysis, age at surgery or hippocampal sclerosis on magnetic resonance imaging (MRI) ipsilateral to surgery was significant for the postsurgical outcome. However, the longitudinal analysis by the GEE model revealed that younger age at surgery [odds ratio (OR), 0.59; 95% confidence interval (CI), 0.43,0.81], absence of secondarily generalized tonic,clonic seizure (2°GTCS; OR, 0.45; 95% CI, 0.26,0.79), and hippocampal sclerosis on MRI (OR, 2.44; 95% CI, 1.11,5.26) were significant predictors of a good surgical outcome. Conclusions: Age at surgery, presence of 2°GTCS, and hippocampal sclerosis on MRI are independent prognostic factors for ATL in MTLE. These findings suggest that MTLE is a progressive disorder, and surgical outcome is better when early ATL is performed. [source] Antiepileptic Drug Withdrawal after Successful Surgery for Intractable Temporal Lobe EpilepsyEPILEPSIA, Issue 2 2005Young Dae Kim Summary:,Purpose: To investigate the prognosis related to antiepileptic drug (AED) discontinuation after successful surgery for intractable temporal lobe epilepsy. Methods: The clinical courses after temporal lobectomies (TLs) were retrospectively analyzed in 88 consecutive patients. All the patients had TLs as the only surgical procedure, and they had been followed up for longer than 3 years. AED discontinuation was attempted if the patient had been seizure free without aura for ,1 year during the follow-up period. Results: Sixty-six (75%) patients achieved complete seizure freedom for ,1 year; 28 patients were seizure free immediately after surgery (immediate success); and 38 patients became seizure free after some period of recurrent seizures (delayed success). AED discontinuation was attempted in 60 (91%) of 66 patients with a successful outcome. In 13 (22%) patients, seizure relapse developed during AED reduction (n = 60), and in seven (12%) patients after discontinuation of AEDs (n = 38). The seizure recurrence rate was not different between the immediate- and delayed-success groups. Among 20 patients with seizure relapse related to AED tapering, nine (45%) of them regained seizure freedom after reinstitution of AED treatment, and AEDs were eventually discontinued in six of them. Seizures that recurred after complete AED discontinuation had a better prognosis than did the seizures that recurred during AED reduction (seizure freedom in 86% vs. 23%). At the final assessment, 54 (61%) patients had been seizure free ,1 year; 37 without AEDs and 17 with AEDs. The successful discontinuation of AEDs was more frequent for patients with a younger age at the time of surgery and for those patients with shorter disease duration. Conclusions: Our results suggest that seizure freedom without aura at ,1 year is a reasonable indication for the attempt at AED discontinuation. The subsequent control of recurrent seizures was excellent, especially if seizures relapsed after the complete discontinuation of AEDs. Younger age at the time of surgery and a shorter disease duration seem to affect successful AED discontinuation for a long-term period. [source] Correlation between 1H MRS and Memory before and after Surgery in Mesial Temporal Lobe Epilepsy with Hippocampal SclerosisEPILEPSIA, Issue 6 2004Lütfü Hano Summary: Purpose: Proton magnetic resonance spectroscopy (1H MRS), which can demonstrate neuronal loss and gliosis, may be used as a sensitive tool for lateralization of temporal lobe epilepsy (TLE). Although the correlation between the memory functions and 1H MRS has been investigated, its predictive value after surgery has not been studied previously. This study evaluated memory and 1H MRS values of medically intractable patients with mesial TLE and hippocampal sclerosis (MTLE-HS) before and after selective amygdalohippocampectomy (SAH). Methods: Twenty-two patients underwent memory tests and 1H MRS investigation before and 6 months after SAH and were compared with nine control subjects. Results: The 1H MRS scores were found to be significantly low on the pathological side of the patients. Both right-sided 1H MRS of right TLE and left-sided 1H MRS values of left TLE patients were correlated only with verbal memory scores. Statistical analysis did not reveal any significance for nonverbal memory scores for both TLE groups on either side, which showed no significant correlation between material specificity and 1H MRS findings. Conversely, regression analyses demonstrated that high right- and low left-sided 1H MRS values obtained before surgery may predict a decline in verbal learning scores after surgery. Conclusions:1H MRS can be considered as a useful tool to determine the lateralization in patients with MTLE-HS before the surgery. Although only a weak relation exists between the MRS values and memory scores, presurgical MRS scores may be predictive for a possible deterioration in verbal memory after surgery. However, further studies with higher numbers of cases are needed for confirmation of the results. [source] Response: Development of Temporal Lobe Epilepsy in 21-day-old RatsEPILEPSIA, Issue 6 2003Catherine Roch No abstract is available for this article. [source] A Kindling Model of Pharmacoresistant Temporal Lobe Epilepsy in Sprague,Dawley Rats Induced by Coriaria Lactone and Its Possible MechanismEPILEPSIA, Issue 4 2003Ying Wang Summary: ,Purpose: The aim of this study was to develop a new animal model of pharmacoresistant temporal lobe epilepsy (TLE) by repeated intramuscular injection of Coriaria lactone (CL) at subthreshold dosages and to explore the mechanisms that might be involved. Methods: Healthy male Sprague,Dawley rats (n = 160) were randomized into four groups during the kindling process: three groups (n = 50 for each group) received CL injection at subthreshold dosages (1.25, 1.5, and 1.75 mg/kg, respectively), and ten received normal saline (NS) injection as a control group. The maximal human adult dosage of carbamazepine (CBZ), valproate (VPA), and phenytoin (PHT) was administered as monotherapy to different groups of kindled rats for 1 month (n = 20 for each group). Changes in EEG recording, seizure number, intensity (expressed as grade 1,5 according to Racine stage), and duration, including spontaneous seizures during different interventions, were compared. The expression of P-170, a multiple drug resistance gene (MDR1) encoding P-glycoprotein, was measured in brain samples from different groups of experimental rats by using an image analysis and measurement system (ImagePro-Plus 4.0). Results: A total of 70 (46.7%) rats were fully kindled with a median of 15 (seven to 20) CL injections. Electrocorticogram (ECoG) including hippocampal (EHG) monitoring revealed the temporal lobe origins of epileptiform potentials, which were consistent with the behavioral changes observed. Spontaneous seizures occurred with frequency and diurnal patterns similar to those of human TLE. The antiepileptic drugs (AEDs) tested lacked a satisfactory seizure control. The maximal P-170 expression was in the kindled rats with AED treatment; the next highest was in the kindled rats without AED intervention. Nonkindled SD rats with CL injection also had increased P-170 expression compared with control SD rats. Conclusions: The study provided a simple and stable animal TLE kindling model with pharmacoresistant properties. The pharmacoresistance observed in the kindled rats to CBZ, VPA, and PHT at maximal human adult dosages together with the increased P-170 expression was a distinct feature of this model. This model might be used in further investigations of the mechanisms involved in pharmacoresistant TLE and for developing new AEDs. [source] Lateralising Value of Neuropsychological Protocols for Presurgical Assessment of Temporal Lobe EpilepsyEPILEPSIA, Issue 3 2003Nozomi Akanuma Summary: ,Purpose: To estimate the value of neuropsychological measurements in determining the side of seizure onset for presurgical assessment in patients with temporal lobe epilepsy. The lateralising value of neuropsychological protocols was evaluated for all patients and in subpopulations depending on surgical outcome with regard to seizure control, speech dominance, neuropathology, and need for intracranial EEG recordings. Methods: A battery of neuropsychological procedures was carried out preoperatively in 125 patients who underwent left (n = 66) or right (n = 59) temporal lobectomies. Binary logistic regression analysis was performed to find sets of variables that allowed the best prediction of the side of seizure onset (assumed to be the operated-on side). Results: Combinations of noninvasive neuropsychological tests and Wada subscores showed the highest lateralising values: 80.8% for all patients, 79.4% in seizure-free patients, 86.0% in patients not rendered seizure free, 85.7% in left speech patients, 77.8% in non,left speech patients, 89.3% in patients with mesial temporal sclerosis (MTS), 78.1% in non-MTS patients, 80.3% in patients who underwent intracranial EEG recordings, and 77.3% in those who did not. Conclusions: The lateralising value (80-90%) of neuropsychological protocols appears similar to that of other tests widely accepted for lateralisation (ictal and interictal scalp EEG and neuroimaging). Attention should be paid to neuropsychological results, particularly from the Wada test, during presurgical assessment of temporal lobe epilepsy, as they can provide strong support for findings from other lateralising tests, particularly in patients with presumed MTS or in left-speech patients. [source] Correlation of Hippocampal Glucose Oxidation Capacity and Interictal FDG-PET in Temporal Lobe EpilepsyEPILEPSIA, Issue 2 2003Stefan Vielhaber Summary: ,Purpose: Interictal [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) demonstrates temporal hypometabolism in the epileptogenic zone of 60,90% of patients with temporal lobe epilepsy. The pathophysiology of this finding is still unknown. Several studies failed to show a correlation between hippocampal FDG-PET hypometabolism and neuronal cell loss. Because FDG is metabolized by hexokinase bound to the outer mitochondrial membrane, we correlated the glucose-oxidation capacity of hippocampal subfields obtained after surgical resection with the corresponding hippocampal presurgical FDG-PET activity. Methods: In 16 patients with electrophysiologically confirmed temporal lobe epilepsy, we used high-resolution respirometry to determine the basal and maximal glucose-oxidation rates in 400-,m-thick hippocampal subfields obtained after dissection of human hippocampal slices into the CA1 and CA3 pyramidal subfields and the dentate gyrus. Results: We observed a correlation of the FDG-PET activity with the maximal glucose-oxidation rate of the CA3 pyramidal subfields (rp = 0.7, p = 0.003) but not for the regions CA1 and dentate gyrus. In accordance with previous studies, no correlation of the FDG-PET to the neuronal cell density of CA1, CA3, and dentate gyrus was found. Conclusions: The interictal hippocampal FDG-PET hypometabolism in patients with temporal lobe epilepsy is correlated to the glucose-oxidation capacity of the CA3 hippocampal subfield as result of impaired oxidative metabolism. [source] Serum S-100 Protein Is Not a Suitable Seizure Marker in Temporal Lobe EpilepsyEPILEPSIA, Issue 10 2002Fritz Leutmezer Summary: ,Purpose: S-100 protein is a sensitive marker of various brain diseases; however, its role in epilepsy is controversially discussed in the literature. We therefore studied the temporal profile of serial concentrations of S-100 protein in serum after secondarily generalized tonic,clonic seizures during video-EEG monitoring. Methods: Ten patients with mesial temporal lobe epilepsy were prospectively studied. Serum S-100 protein was measured after a seizure-free period of ,24 h (baseline) and 30 min, 3, 6, 12, and 24 h after a secondarily generalized tonic,clonic seizure of temporal lobe origin in nine and a convulsive status epilepticus in one patient. Results: All S-100 levels were within the normal range, except for those of one patient at baseline. Mean values were 0.045 ,g/L (range, 0.003,0.13 ,g/L) at baseline, 0.038 ,g/L (range, 0.003,0.09 ,g/L) at 30 min, 0.036 ,g/L (range, 0.003,0.08 ,g/L) at 3 h, 0.034 ,g/L (range, 0.003,0.07 ,g/L) at 6 h, 0.034 ,g/L (range, 0.003,0.08 ,g/L) at 12 h, and 0.035 ,g/L (range, 0.003,0.09 ,g/L) at 24 h after seizure offset. There were no significant differences between mean concentrations at any interval postictally. Conclusions: We could not detect any significant alterations in serum S-100 protein concentration either after a single secondarily generalized tonic,clonic seizure or after convulsive status epilepticus in patients with temporal lobe epilepsy. Our data do not confirm previous work, which suggested serum S-100 protein to be a suitable marker for epileptic seizures. [source] A Short-echo-time Proton Magnetic Resonance Spectroscopic Imaging Study of Temporal Lobe EpilepsyEPILEPSIA, Issue 9 2002Robert J. Simister Summary: ,Purpose: We used short-echo-time proton magnetic resonance spectroscopy imaging (MRSI) to study metabolite concentration variation through the temporal lobe in patients with temporal lobe epilepsy (TLE) with and without abnormal MRI. Methods: MRSI was performed at TE = 30 ms to study 10 control subjects, 10 patients with TLE and unilateral hippocampal sclerosis, and 10 patients with TLE and unremarkable MRI (MRI negative). We measured the concentrations of N -acetyl aspartate +N -acetyl aspartyl-glutamate (NAAt), creatine (Cr), choline (Cho), glutamate + glutamine (Glx), and myoinositol, in the anterior, middle, and posterior medial temporal lobe (MTL), and in the posterior lateral temporal lobe. Segmented volumetric T1 -weighted MRIs gave the tissue composition of each MRSI voxel. Normal ranges were defined as the control mean ± 3 SD. Results: In the hippocampal sclerosis group, seven of 10 had abnormally low NAAt in the ipsilateral anterior MTL. In the MRI-negative group, four of 10 had low NAAt in the middle MTL voxel ipsilateral to seizure onset. Metabolite ratios were less sensitive to abnormality than was the NAAt concentration. Group analysis showed low NAAt, Cr, and Cho in the anterior MTL in hippocampal sclerosis. Glx was elevated in the anterior voxel contralateral to seizure onset in the MRI-negative group. Metabolite concentrations were influenced by voxel position and tissue composition. Conclusions: (a) Low NAAt, Cr, and Cho were features of the anterior sclerotic hippocampus, whereas low NAAt was observed in the MRI-negative group in the middle MTL region. The posterior temporal lobe regions were not associated with significant metabolite abnormality; (b) The two patient groups demonstrated different metabolite profiles across the temporal lobe, with elevated Glx a feature of the MRI-negative group; and (c) Voxel tissue composition and position influenced obtained metabolite concentrations. [source] FDG-PET Images Quantified by Probabilistic Atlas of Brain and Surgical Prognosis of Temporal Lobe EpilepsyEPILEPSIA, Issue 9 2002Sang Kun Lee Summary: ,Purpose: This study evaluated the relation between hypometabolism, diagnosed by fluorodeoxyglucose positron emission tomography (FDG-PET), and the surgical outcome of a large and homogeneous series of cases of mesial temporal lobe epilepsy (mTLE), by using a probabilistic atlas of the human brain (statistical probabilistic anatomical maps: SPAM). Methods: Ninety-five surgically proven intractable mTLE patients and 22 age-matched controls were spatially normalized to the average brain PET template of international consortium of brain mapping (ICBM). The diagnosis of mTLE was confirmed by the presence of hippocampal sclerosis on magnetic resonance imaging (MRI) and video-EEG monitoring. Counts from normalized PET images were multiplied by the probability from 98 volumes of interest (VOIs) of SPAM. Asymmetric indexes (AIs) reflecting the severity of hypometabolism were calculated by counts of selected 12 VOIs from SPAM images in both temporal lobes. Extent of hypometabolism was determined by the number of voxels showing decreased metabolism in each VOI segmented by SPAM. Results: Of the 95 patients studied, 76 (80%) were seizure free, and 19 (20%) had postoperative seizures for the ,2-year follow-up period. No significant association between the severity of hypometabolism in each VOI of the temporal lobe and surgical outcome was identified (p > 0.05). The number of voxels showing decreased hypometabolism was not significantly different between the good- and poor-outcome groups (p > 0.05). Conclusions: Our results demonstrated that focal severity and extent of hypometabolism quantified by a probabilistic atlas of brain were not related to the surgical outcome in mTLE patients who had hippocampal sclerosis on MRI. We should develop a more localized and specified anatomic map for mTLE for further results. [source] Magnetic Resonance Imaging in the Study of the Lithium,Pilocarpine Model of Temporal Lobe Epilepsy in Adult RatsEPILEPSIA, Issue 4 2002Catherine Roch Summary: ,Purpose: In temporal lobe epilepsy, it remains to be clarified whether hippocampal sclerosis is the cause or the consequence of epilepsy. We studied the temporal evolution of the lesions in the lithium,pilocarpine model of epilepsy in the rat with magnetic resonance imaging (MRI) to determine the progressive morphologic changes occurring before the appearance of chronic epilepsy. Methods: MRI was performed on an MR scanner operating at 4.7 T. We followed the evolution of lesions using T2 - and T1 -weighted sequences before and after the injection of gadolinium from 2 h to 9 weeks. Results: At 2 h after status epilepticus (SE), a blood,brain barrier breakdown could be observed only in the thalamus; it had disappeared by 6 h. At 24 h after SE, edema was present in the amygdala and the piriform and entorhinal cortices together with extensive neuronal loss; it disappeared progressively over a 5-day period. During the chronic phase, a cortical signal reappeared in all animals; this signal corresponded to gliosis, which appeared on glial fibrillary acidic protein (GFAP) immunohistochemically stained sections as hypertrophic astrocytes with thickened processes. In the hippocampus, the correlation between histopathology and T2 -weighted signal underscored the progressive constitution of atrophy and sclerosis, starting 2 days after SE. Conclusions: These data show the reactivity of the cortex that characterizes the initial step leading to the development of epilepsy and the late gliosis that could result from the spontaneous seizures. Moreover, it appears that hippocampal sclerosis progressively worsened and could be both the cause and the consequence of epileptic activity. [source] Prognostic Implication of Contralateral Secondary Electrographic Seizures in Temporal Lobe EpilepsyEPILEPSIA, Issue 11 2000Ki Hyeong Lee Summary: Purpose: Interhemispheric propagation of seizures in temporal lobe epilepsy is frequently noted during intracranial EEG monitoring. We hypothesized that a distinct secondary electrographic seizure (DSES) in the temporal lobe contralateral to primary seizure onset may be an unfavorable prognostic indicator. Methods: We reviewed intracranial depth electrode EEG recordings, 1-year outcome, and medical records of 51 patients (M 29, F 22: age 15,64 years) who underwent anterior temporal lobectomy during 1988,96. We defined DSES as a seizure that spread to the contralateral temporal lobe and produced distinct contralateral EEG features. The distinct feature was focal involvement of one or two electrode contacts at onset, which starts and evolves independently from the ipsilateral temporal lobe. We considered DSES as the predominant seizure pattern when it occurred in more than one half of the patients' recorded seizures. Results: Only nine of 19 (47%) patients with predominant DSES had a 1-year seizure-free outcome, whereas 27 of 32 (84%) patients without predominant DSES had a 1-year seizure-free outcome (p <0.01). Bitemporal independent seizures were more common in patients with predominant DSES (9/19 versus 0/32; p <0.001). Conclusion: Our results suggest that distinct contralateral secondary electrographic seizure is a predictor of unfavorable outcome and is also more likely to be associated with bitemporal seizures. [source] Chronological Changes of Plasma Homovanillic Acid (HVA) and 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) Levels in 4 Patients with Temporal Lobe Epilepsy who Developed Psychosis-Like Symptoms (Hallucination and Delusion) During Zonisamide (ZNS) Administration.EPILEPSIA, Issue 2000Takuya Ueno Purpose: Zonisamide (ZNS) is a relatively new antiepileptic drug with an extensive therapeutic spectrum. However, ZNS can produce psychiatric side effects. In this study, we serially measured plasma hoinovaniliic acid (HVA) and 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) levels in 4 patients with epilepsy who developed psychosis-like symptoms (hallucinations and delusions) during ZNS administration. Methods: Subjects comprised 4 patients (3 males and 1 female) with temporal lobe epilepsy ranging in age from 18 to 28 years. Intervals from the start of ZNS administration to the appearance of psychiatric symptoms ranged from 36 to 707 days. Intervals from achievement of the maximal dose to the appearance of psychiatric symptoms ranged from 2 to 240 days. In these 4 patients, the maximal doses of ZNS ranged from 300 to 600 mg/day. In 3 cases, serum ZNS levels were within the effective therapeutic concentration range wlicn syinptoms appeared. However, in 1 case, the serum ZNS level exceeded thc therapeutic level. In all cases, psychiatric symptoms disappeared after ZNS was switched to other antiepileptic drugs and anti-psychotic agents (2-5 mg/day of haloperidol or 10 mg/day of thioridazine) were added. In these cases, we serially measured plasma HVA and MHPG concentrations. Results: Case 1 was a 28-year-old male. Delusions of persecution appeared 190 days after ZNS administration was started. HVA levels at the appearance of psychiatric symptoms were 12.7 ng/ml and HVA levels at the disappearance of psychiatric symptoms were 7.4 ng/ml. MHPG levels at the appearance of psychiatric symptoms were 14.5 ng/ml and MHPG levels at the disappearance of psychiatric symptoms were 6. I ng/ml. When psychiatric symptoms appeared, the plasma HVA level was increased, whereas the MHPG level was slightly increased. Case 2 was an 18-year-old female. Auditory hallucinations appeared 320 days after ZNS first was administered. HVA levels at the appearance of psychiatric symptoms were 9.6- 10.0 nghl and HVA levels at the disappearance of psychiatric symptoms were 5.3,6.1 ng/ml. MHPG levcls at the appearance of psychiatric symptoms were 4.14.2 ng/ml and MHPG levels at the disappearance of psychiatric symptoms were 3.1 ng/ml. When psychiatric symptoms appeared, the plasma HVA level was increased, but there was no increase in MHPG. Case 3 was an 18-year-old male. Delusion of persecution appeared 707 days after ZNS administration was started. HVA levels at the appearance of psychiatric symptoms were 10.6 ng/ml and HVA levels at the disappearance of psychiatric symptoms were 7.2 ngiml. MHPG levels at the appearance of psychiatric symptoms were 5.3 ng/ml and MHPG levels at the disappearance of psychiatric symptoms were 3.9 ng/ml. When psychiatric symptoms appeared, plasma HVA level was increased, while the MHPG level was slightly increased. Case 4 was a 20-year-old male. Auditory hallucination appeared 36 days after ZNS was administered. HVA levels at the appearance of psychiatric symptoms were 13.6 ng/ml and HVA levels at the disappearance of psychiatric symptoms were 7.2 ng/ml. MHPG levels at the appearance of psychiatric symptoms were 5.4 ng/ml and MHPG levels at the disappearance of psychiatric symptoms were 6. I ng/ml. When psychiatric symptoms appeared, the plasma HVA level was increased, but there was no increase in MHPG. Conclusions: In all patients, the plasma HVA levels at the appearance of psychiatric symptoms was higher than the corresponding level at time of disappearance of psychiatric symptoms. Psychiatric symptoms may have been associated with activation of dopaniine by ZNS. MHPG levels were slightly increased in 2 cases. However, in thc other 2 cases, there were no changes in MHPG. The influence of ZNS on neurotransmitter metabolites should be further investigated in a larger nuniber of patients. [source] Language-Related Potentials in Temporal Lobe Epilepsy Before and After Surgical TreatmentEPILEPSIA, Issue 2000Toshihiko Ito Purpose: Temporal lobectomy has contributed to treatment for medically intractable epilepsies. However, influence of the surgical treatment on cognitive function is not still clear, especially from the electrophysiological viewpoint. N400, an event related potential (ERP) named for its negative polarity and peak latency of 400 ms, is reported to be an electrophysiological sign of neural activities associated with semantic priming in language perception. In the present study, ERPs are applied to evaluate the cognitive function of temporal lobe epilepsy before and after temporal lobectomy. Methods: Two patients with intractable temporal lobe epilepsy participated in this study. Fifteen normal subjects served as controls. The incongruous sentence task (Kutas and Hillyard 1980) was used to record N400 components in an auditory modality. Two types of sentences (40 Japanese sentences for each type) were prepared, in which the terminal words were either semantically congruent or incongruent. The scntences were randomly presented at approximately 65 dB SPL peak intensity. ERPs were recorded according to the international 10,20 system, with a balanced non-cephalic electrode reference and 2 1 channels. The band-pass filter was set from 0.5 to 30 Hz, and the ERPs were sampled at 500 Hz from 200 ms before the onset of terminal words to 824 ms post-stimulus. Waves were calculated by subtracting ERPs in the congruent condition from those in the incongruent condition. N400 was scored as the most negative point between 250 and 450 ms in the subtraction waves. Amplitudes were measured from the baseline of 100 ms before the terminal words. Motor responses were also measured with a right index finger, to estimate the accuracy of understanding sentences. Results: Case I was a 22-year-old male who had intractable epilepsy for 7 years. Magnetic resonance imaging (MRI) showed high-intensity signals in the right amygdalo-hippocampal region. The epileptic seizures were confirmed to originate from the region hy electroencephalography/closed-circuit television monitoring, and single-photon-emission computed tomography. ERPs were recorded I month before and after the right anterior temporal lobectomy. Before the surgery, the rate of correct responses showed no difference between the patient (96 %) and the controls (96 %). The amplitudes of N400 for the patient reduced in the right frontal and central areas (F4, C4), comparing to 99 % confidence limit for control subjects. After the surgery, the rate of correct responses was 97 %, and the amplitudes reduced in the right central, parietal, and posterior temporal areas (C4, P4, 0 2, T6). Case 2 (37-year-old female) had intractable epilepsy for 30 years. MRI showed brain atrophy in the right hippocampal region. The epileptic seizures were confirmed to originate from the region. N400 was recorded 3 months after the resection. The rate of correct responses was 95 %. The amplitudes of N400 were lower in the right frontal, parietal, and temporal areas (electrodes Fp2, F4, P4, T6, Pz), comparing to 99 % confidence limit of controls. Conclusions: Before the lpbectomy, the reduction of amplitudes of N400 indicated that the pathogenesis of intractable temporal lobe epilepsy would influence the process of semantic priming in language perception. After the resection, it was suggested that the right temporal lobectomy might affect the cognitive function in the brain from electrophysiological aspects. We could benefit from further study including analysis of the discrepancy between the amplitudes of N400 and behavioral responses. [source] Magnetic Resonance Imaging Follow-up of Progressive Hippocampal Changes in a Mouse Model of Mesial Temporal Lobe EpilepsyEPILEPSIA, Issue 6 2000Viviane Bouilleret Summary: Purpose: Hippocampal sclerosis (HS) is the most frequent lesion found in mesial temporal lobe epilepsy (mTLE). MR imaging is considered to be the most sensitive and specific method to detect HS. Despite extensive studies performed on humans and except in a recent study, the morphologic pattern of HS is usually analyzed when the disease has already fully developed, thus not allowing any insight into the mapping of the progressive morphologic changes inducing the development of mTLE. We have recently characterized a model of mTLE that reproduces the unilateral pattern of HS, induced by intrahippocampal injection of low doses of kainate (KA) in mice. Methods: In this study, we monitored the temporal evolution of the development of HS in this model of mTLE by using T2 -weighted sequence, T2 -relaxation time measurements, and T1 -weighted spin-echo technique after injection of gadolinium, from 1 h to 120 days after KA injection. Results: HS induced by intrahippocampal KA injection occurred in two phases. First, we observed a transient hyperintense T2 -weighted signal in the cortex above the injected hippocampus, most likely indicative of vasogenic edema partly due to the neurotoxic effect of KA. The concomitant increase in the T2 signal in the injected hippocampus and ipsilateral amygdala likely reflects the phase of cytotoxic edema occurring probably in relation to the excitotoxic consequences of both KA and seizure activity. Second, from 15 days on, a persistent unilateral increased T2 signal was detected in the hippocampus, which most probably reflects gliosis. Conclusions: Our findings indicate that longitudinal follow-up would permit a better understanding of the mechanisms underlying the constitution of HS in humans and eventually development of prevention strategies. [source] T2-Weighted and T2 Relaxometry Images in Patients with Medial Temporal Lobe EpilepsyJOURNAL OF NEUROIMAGING, Issue 3 2006Ana Carolina Coan MD ABSTRACT Purpose. Quantification of increased T2-weighted MRI signal that is associated with hippocampal sclerosis (HS) can be performed through (1) mean of hippocampal signal in single-echo T2 MRI and (2) hippocampal T2 relaxometry. It is not clear whether these two techniques are equivalent. In this study, we compare the hippocampal signal, detected by single-echo T2 quantification and by T2 relaxometry, in patients with medial temporal lobe epilepsy (MTLE). Methods. We studied magnetic resonance images from 50 MTLE patients and 15 healthy subjects. We compared the quantification of a T2 signal from single echo images to T2 relaxometry, both obtained from a manually traced region of interest (ROI) in coronal slices involving the whole hippocampus. Repeated measures ANOVA was used to evaluate the differences in the distribution of the Z -scores from single-echo T2 quantification and T2 relaxometry within subjects. Results. We observed a significant difference between the measurements obtained from single-echo T2 quantification and T2 relaxometry (P < .001). Measurements from head, body, and tail of the hippocampus were different (P=.04), with a significant interaction between anatomic location and type of measurement used (P= .008). Post hoc paired comparisons revealed that T2 relaxometry yielded greater Z -scores for the body (P= .002) and tail (P < .0001). Conclusions. For each subject with MTLE, T2 relaxometry was able to detect a higher signal in the body and tail of the hippocampus compared to single-echo T2. This is a possible indicator that T2 relaxometry is more sensitive in detecting T2 abnormalities within the body and tail of the hippocampus in patients with MTLE. [source] Clinical features of seizures associated with parahippocampal/inferior temporal lesions compared to those with hippocampal sclerosisEPILEPSIA, Issue 9 2010Laura Mirandola Summary Temporal lobe epilepsy (TLE) is not a unitary electroclinical imaging syndrome. We asked if seizures arising from the parahippocampal-inferior temporal (PIT) region differ from those associated with hippocampal sclerosis (HS). The electroclinical features of 22 patients with HS and 14 patients with lesions in the PIT region who underwent epilepsy surgery and were seizure free for at least 2 years postoperatively were analyzed retrospectively. Patients with PIT lesions had a higher frequency of hypermotor and bilateral features and a lower frequency of behavioral arrest at the onset of seizure compared to cases with HS, suggesting that TLE originating in the PIT area can mimic frontal lobe epilepsy or contralateral mesial TLE. [source] Decreased hippocampal volume on MRI is associated with increased extracellular glutamate in epilepsy patientsEPILEPSIA, Issue 8 2008Idil Cavus Summary Purpose: Temporal lobe epilepsy (TLE) is associated with smaller hippocampal volume and with elevated extracellular (EC) glutamate levels. We investigated the relationship between the hippocampal volume and glutamate in refractory TLE patients. Methods: We used quantitative MRI volumetrics to measure the hippocampal volume and zero-flow microdialysis to measure the interictal glutamate, glutamine, and GABA levels in the epileptogenic hippocampus of 17 patients with medication-resistant epilepsy undergoing intracranial EEG evaluation. The relationships between hippocampal volume, neurochemical levels, and relevant clinical factors were examined. Results: Increased EC glutamate in the epileptogenic hippocampus was significantly related to smaller ipsilateral (R2= 0.75, p < 0.0001), but not contralateral hippocampal volume when controlled for glutamine and GABA levels, and for clinical factors known to influence hippocampal volume. Glutamate in the atrophic hippocampus was significantly higher (p = 0.008, n = 9), with the threshold for hippocampal atrophy estimated as 5 ,M. GABA and glutamine levels in the atrophic and nonatrophic hippocampus were comparable. Decreased hippocampal volume was related to higher seizure frequency (p = 0.008), but not to disease duration or febrile seizure history. None of these clinical factors were related to the neurochemical levels. Conclusions: We provide evidence for a significant association between increased EC glutamate and decreased ipsilateral epileptogenic hippocampal volume in TLE. Future work will be needed to determine whether the increase in glutamate has a causal relationship with hippocampal atrophy, or whether another, yet unknown factor results in both. This work has implications for the understanding and treatment of epilepsy as well as other neurodegenerative disorders associated with hippocampal atrophy. [source] Molecular Neuropathology of Temporal Lobe Epilepsy: Complementary Approaches in Animal Models and Human Disease TissueEPILEPSIA, Issue 2007Michael Majores Summary:, Patients with temporal lobe epilepsies (TLE) frequently develop pharmacoresistance to antiepileptic treatment. In individuals with drug-refractory TLE, neurosurgical removal of the epileptogenic focus provides a therapy option with high potential for seizure control. Biopsy specimens from TLE patients constitute unique tissue resources to gain insights in neuropathological and molecular alterations involved in human TLE. Compared to human tissue specimens in most neurological diseases, where only autopsy material is available, the bioptic tissue samples from pharmacoresistant TLE patients open rather exceptional preconditions for molecular biological, electrophysiological as well as biochemical experimental approaches in human brain tissue, which cannot be carried out in postmortem material. Pathological changes in human TLE tissue are multiple and relate to structural and cellular reorganization of the hippocampal formation, selective neurodegeneration, and acquired changes of expression and distribution of neurotransmitter receptors and ion channels, underlying modified neuronal excitability. Nevertheless, human TLE tissue specimens have some limitations. For obvious reasons, human TLE tissue samples are only available from advanced, drug-resistant stages of the disease. However, in many patients, a transient episode of status epilepticus (SE) or febrile seizures in childhood can induce multiple structural and functional alterations that after a latency period result in a chronic epileptic condition. This latency period, also referred to as epileptogenesis, cannot be studied in human TLE specimens. TLE animal models may be particularly helpful in order to shed characterize new molecular pathomechanisms related to epileptogenesis and open novel therapeutic strategies for TLE. Here, we will discuss experimental approaches to unravel molecular,neuropathological aspects of TLE and highlight characteristics and potential of molecular studies in human and/or experimental TLE. [source] Hippocampal Pathology in the Human Neuronal Ceroid-Lipofuscinoses: Distinct Patterns of Storage Deposition, Neurodegeneration and Glial ActivationBRAIN PATHOLOGY, Issue 4 2004Jaana Tyynelä The neuronal ceroid-lipofuscinoses (NCLs) are recessively inherited lysosomal storage diseases, currently classified into 8 forms (CLN1-CLN8). Collectively, the NCLs constitute the most common group of progressive encephalopathies of childhood, and present with visual impairment, psychomotor deterioration and severe seizures. Despite recent identification of the underlying disease genes, the mechanisms leading to neurodegeneration and epilepsy in the NCLs remain poorly understood. To investigate these events, we examined the patterns of storage deposition, neurodegeneration, and glial activation in the hippocampus of patients with CLN1, CLN2, CLN3, CLN5 and CLN8 using histochemistry and immunohistochemistry. These different forms of NCL shared distinct patterns of neuronal degeneration in the hippocampus, with heavy involvement of sectors CA2-CA4 but relative sparing of CA1. This selective pattern of degeneration was also observed in immunohistochemically identified interneurons, which exhibited a graded severity of loss according to phenotype, with calretinin-positive interneurons relatively spared. Furthermore, glial activation was also regionally specific, with microglial activation most pronounced in areas of greatest neuronal loss, and astrocyte activation prominent in areas where neuronal loss was less evident. In conclusion, the NCLs share a common pattern of selective hippocampal pathology, distinct from that seen in the majority of temporal lobe epilepsies. [source] Clinical applications of 1H-MR spectroscopy in the evaluation of epilepsies , What do pathological spectra stand for with regard to current results and what answers do they give to common clinical questions concerning the treatment of epilepsies?ACTA NEUROLOGICA SCANDINAVICA, Issue 4 2003T. Hammen Nuclear magnetic resonance spectroscopy (1H-MRS) is a non-invasive method in detecting abnormal spectra of various brain metabolites containing N -acetylaspartate (NAA), Choline (Cho), Creatine (Cr), , -Aminobutyric acid (GABA) and Glutamate. Technical processing of the MR-systems, improved automated shimming methods and further development of special shim coils increase the magnetic field homogeneity and lead to a better spectral quality and spectral resolution. The handling of the systems becomes more user-friendly and is more likely to be used in routine diagnostics. The 1H-MRS has become a diagnostic tool for assessing a number of diseases of the central nervous system mainly including epilepsies and brain tumours. The role of 1H-MRS in the assessment of epilepsies will probably increase in future. In the following article, the principles of 1H-MRS and an overview of it in the evaluation and treatment of epilepsies with special regard to temporal lobe epilepsies (TLE) has been illustrated. [source] Continuous local intrahippocampal delivery of adenosine reduces seizure frequency in rats with spontaneous seizuresEPILEPSIA, Issue 9 2010Annelies Van Dycke Summary Purpose:, Despite different treatment options for patients with refractory epilepsy such as epilepsy surgery and neurostimulation, many patients still have seizures and/or drug-related cerebral and systemic side effects. Local intracerebral delivery of antiepileptic compounds may represent a novel strategy with specific advantages such as the option of higher local doses and reduced side effects. In this study we evaluate the antiepileptic effect of local delivery of adenosine in the kainic acid rat model, a validated model for temporal lobe epilepsy. Methods:, Fifteen rats, in which intraperitoneal kainic acid injection had induced spontaneous seizures, were implanted with a combination of depth electrodes and a cannula in both hippocampi. Cannulas were connected to osmotic minipumps to allow continuous hippocampal delivery. Rats were freely moving and permanently monitored by video-EEG (electroencephalography). Seizures were scored during 2 weeks of local hippocampal delivery of saline (baseline), followed by 2 weeks of local adenosine (6 mg/ml) (n = 10) or saline (n = 5) delivery (0.23 ,l/h) (treatment). In 7 of 10 adenosine-treated rats, saline was also delivered during a washout period. Results:, During the treatment period a mean daily seizure frequency reduction of 33% compared to the baseline rate was found in adenosine-treated rats (p < 0.01). Four rats had a seizure frequency reduction of at least 50%. Both nonconvulsive and convulsive seizures significantly decreased during the treatment period. In the saline-control group, mean daily seizure frequency increased with 35% during the treatment period. Conclusions:, This study demonstrates the antiseizure effect of continuous adenosine delivery in the hippocampi in rats with spontaneous seizures. [source] Reliability of patterns of hippocampal sclerosis as predictors of postsurgical outcomeEPILEPSIA, Issue 9 2010Maria Thom Summary Purpose:, Around one-third of patients undergoing temporal lobe surgery for the treatment of intractable temporal lobe epilepsy with hippocampal sclerosis (HS) fail to become seizure-free. Identifying reliable predictors of poor surgical outcome would be helpful in management. Atypical patterns of HS may be associated with poorer outcomes. Our aim was to identify atypical HS cases from a large surgical series and to correlate pathology with clinical and outcome data. Methods:, Quantitative neuropathologic evaluation on 165 hippocampal surgical specimens and 21 control hippocampi was carried out on NeuN-stained sections. Neuronal densities (NDs) were measured in CA4, CA3, CA2, and CA1 subfields. The severity of granule cell dispersion (GCD) was assessed. Results:, Comparison with control ND values identified the following patterns based on the severity and distribution of neuronal loss: classical HS (CHS; n = 60) and total HS (THS; n = 39). Atypical patterns were present in 30% of cases, including end-folium sclerosis (EFS; n = 5), CA1 predominant pattern (CA1p; n = 9), and indeterminate HS (IHS, n = 35). No HS was noted in 17 cases. Poorest outcomes were noted for no-HS, and CA1p groups with 33,44% International League Against Epilepsy (ILAE) class I at up to 2 years follow-up compared to 69% for CHS (p < 0.05). GCD associated with HS type (p < 0.01), but not with outcome. Conclusions:, These findings support the identification and delineation of atypical patterns of HS using quantitative methods. Atypical patterns may represent distinct clinicopathologic subtypes and may have predictive value following epilepsy surgery. [source] | ||||||||||||||||||||||||||||