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Results for “Temporal Lobe Resection”

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PubMed2003

Spikes on the postoperative EEG are related to preoperative spike frequency and postoperative seizures.

PURPOSE: To investigate the factors which influence the persistence of interictal epileptiform discharges (IED) after epilepsy surgery. METHODS: In this retrospective study we included patients with intractable medial temporal lobe epilepsy (MTLE) who underwent presurgical evaluation including high-resolution MRI and video-EEG monitoring with seizure registration prior to an anterior temporal lobe resection. The postsurgical outcome was assessed by our team 6 months and 2 years after the surgery. RESULTS: One hundred and forty-seven patients fulfilled the inclusion criteria. The mean age of the patients was 31.8 (range 16-59 years). In 22 patients (15%) interictal epileptiform discharges were present on the postoperative routine EEG. We found that both the preoperative spike frequency ( P < 0.001 ) and postoperative seizures ( P = 0.04 ) were independently associated with the presence of IED on the postoperative routine EEG. The preoperative spike frequency was not associated with the postoperative outcome. The extent of resection showed no influence on the presence of postoperative IED. CONCLUSION: We hypothesize that two factors independently influence the presence of postoperative spikes: chronic interictal disturbance (represented as preoperative spike frequency) and the acute (postoperative) seizures. Our study confirmed that persistent postoperative IED had a prognostic value regarding the outcome of the epilepsy surgery.

Action Potentials↗

PubMed1997

Distinct neurodevelopmental patterns of bcl-2 and bcl-x expression are altered in glioneuronal hamartias of the human temporal lobe.

Bcl-2 and bcl-xL are homologous proteins that inhibit cell death and are expressed in the nervous system. We tested the hypothesis that aberrant expression of such "death suppressor" molecules may promote the survival of abnormal cells in glioneuronal lesions associated with temporal lobe epilepsy. The normal pattern of bcl-2 and bcl-x expression was studied in postmortem human fetal and adult temporal lobes. Formalin-fixed, paraffin-embedded tissue sections were probed for bcl-2 and bcl-x in immunohistochemical studies using well-characterized primary antibodies that had been raised against epitopes that are not shared by these proteins. Strong staining for both proteins was observed in the ventricular zone and in migrating, postmitotic and postmigratory young neurons of the neocortex, hippocampus, and entorhinal cortex from 6 to 20 weeks gestational age (GA). However, bcl-2 immunoreactivity gradually decreased to weak or nondetectable levels between 20 and 39 weeks GA, while strong bcl-x staining of neurons persisted throughout fetal development and into adulthood. Twenty-eight temporal lobe resections from children and adults ranging in age from 1 to 45 years (mean=19 years) with intractable epilepsy were then screened for differences in the pattern of bcl-2 and bcl-x expression compared to normal controls. Bcl-2 (but not bcl-x) was strongly immunoreactive in small, immature-appearing cells that were components of microscopic glioneuronal aggregates (hamartias) and that have been shown previously to express an embryonic form of the neural cell adhesion molecule. These immature cells were immunonegative for standard markers of neuronal and glial lineage and were negative for Ki67, suggesting that they are post-mitotic. The persistent expression of bcl-2 and apparent downregulation of bcl-x in these cells represent deviations from the normal ontogeny of these molecules in the human nervous system. These data suggest that dysregulation of bcl-2 and related proteins may be involved in the pathogenesis of some temporal lobe malformative lesions.

Adolescent↗

PubMed1988

Computer enhancement of scalp-sphenoidal ictal EEG in patients with complex partial seizures.

Color topographic maps of scalp/sphenoidal ictal EEG records were computer-generated in 5 patients with medically refractory complex partial seizures of suspected temporal lobe origin. Seven ictal EEG records were analyzed by parsing them into a series of 1.28 sec epochs. User-interactive, computer techniques were utilized to replace eye movement and other artifactual segments in the peri-ictal records with nearby uncontaminated EEG segments. Artifact replacement techniques were designed to minimize or eliminate EEG discontinuities in those epochs in which artifact was removed. Significance probability maps consisting of z scores were constructed by comparing theta band power for each 1.28 sec epoch composing the peri-ictal period with the mean and standard deviation of theta power computed from a pre-ictal baseline period consisting of 50-75 epochs. The resulting maps were compared with available independent clinical measures in order to validate their usefulness. The independent measures consisted of non-invasive data (visual impressions of raw scalp/sphenoidal ictal EEGs and positron emission tomography) and invasive data (depth ictal recordings, pathological findings in resected temporal lobes, and surgical outcome). Ictal topographic maps appeared to either confirm or provide new localizing information in all 5 patients. In 3 of 5 patients, several seconds of localized theta suppression preceded localized theta augmentation during the peri-ictal period. The transition between the 2 states was very rapid (approximately 2 sec). The spatial locus of suppression was always in agreement with the spatial locus of augmentation. In general, the maps were considerably easier to interpret than the raw scalp/sphenoidal ictal EEGs: (1) Localized theta suppression in the maps was not evident from visual inspection of the raw ictal scalp/sphenoidal EEG. (2) Clear localized theta augmentation in the maps occurred well before the appearance of unambiguous phase reversals in the raw scalp/sphenoidal ictal EEG. (3) Mapping data were correctly lateralizing in 1 patient in whom visual interpretation of the raw scalp/sphenoidal ictal EEGs was considered non-localizing but often suggestive of a seizure origin in the hemisphere contralateral to that implicated by depth recordings, PET, and pathological data. These results suggest that topographic mapping of scalp/sphenoidal ictal EEGs in patients with complex partial seizures may eventually prove to be a useful adjunct to the interpretation of raw ictal recordings.

Brain↗

PubMed2003

A prospective study of the requirement for and the provision of epilepsy surgery in the United Kingdom.

PURPOSE: Of the 30,000 persons in whom epilepsy develops annually in the United Kingdom, in approximately 6000 (20%), intractability develops. Some of these patients will be appropriate for epilepsy surgery. We aimed to estimate the number of patients who should be considered surgical candidates, by extrapolation from a population-based study of prognosis and the number who are receiving epilepsy surgery, by a survey of U.K. neurosurgeons. METHODS: We identified the number of patients who may eventually require surgery from a prospective cohort of patients with newly diagnosed epilepsy. We identified all U.K. neurosurgeons who had performed any epilepsy surgery in the past year. Each identified surgeon prospectively recorded the number and types of operations carried out for 6 months. RESULTS: Of newly diagnosed patients each year, 450 (1.5%) may eventually require surgery. Thirty-two respondents (22% of all U.K. neurosurgeons) reported that they performed epilepsy surgery. The 211 operations were carried out in the 6 months surveyed (422 operations annually or 13 per surgeon per year). Temporal lobe resection (77%) was the most common procedure. CONCLUSIONS: Based on a prevalence of 5/1,000 persons with epilepsy, < or =4,500 patients in the U.K. require epilepsy surgery. Every year, 450 patients with newly diagnosed epilepsy who may eventually require surgery are added to this "surgical pool." At the current annual rate of operations, a large number of refractory patients remain untreated. This is probably partly because many patients are not referred for specialist care and therefore remain underinvestigated.

Adolescent↗

PubMed2000

The wada test: prediction of focus lateralization by asymmetric and symmetric recall.

PURPOSE: The intracarotid amytal test is commonly used as a predictor of memory dysfunctioning after anterior temporal lobe resection (ATL) for intractable epilepsy. Asymmetry in memory scores can provide focus lateralizing information. In this study the predictive value of a set of Wada test parameters was analyzed, including patients with symmetrical memory scores. METHODS: The Wada test was carried out in 226 patients undergoing ATL (94 L, 132 R). Data were collected on item recognition (five items), story recall, amytal dose, presentation time, EEG and arterial filling of amytal. A logistic regression analysis was performed on these data in order to find a set of variables which could best predict the side of seizure onset. RESULTS: The analysis yielded four variables, i.e. both memory scores, story recall after right-sided injection and presentation time of stimuli after left-sided injection which could correctly predict seizure lateralization in 85% of the cases. Misclassification was lower for right foci than for left foci. Seizure outcome was four times more favourable in the correctly classified patients. CONCLUSIONS: The results suggest that prediction of focus lateralization in temporal lobe epilepsy can be fairly exact even if left/right memory scores are equal. Performing the Wada test with only five memory items keeps the time window of active amytal short enough and gives accurate information about contralateral temporal lobe functioning. The classification scheme can be useful in predicting a lowered chance of seizure freedom.

Adult↗

PubMed1976

Temporal lobe epilepsy: types of seizures, age, and surgical results.

Types of seizures, age at onset of epilepsy, preoperative duration of epilepsy, and age at operation were studied in the literature and in 74 patients who underwent unilateral temporal lobe resection in 1960-1969 in Denmark. The medical and surgical series were compared. The age at onset was significantly lower in the surgical series. Prognostically favourable factors were: i) preoperative presence of a single type of seizure; ii) duration of epilepsy of less than 4 years, and in grand mal epilepsy of less than 1 year; iii) operation for epilepsy in or before early adulthood. Prognostically unfavourable factors were i) preoperative presence of grand mal; ii) age at onset of epilepsy or of the first grand mal seizure between 5 and 20 years; iii) preoperative duration of psychomotor epilepsy over 10 years.

Adolescent↗

PubMed1999

Frequency domain EEG source localization of ictal epileptiform activity in patients with partial complex epilepsy of temporal lobe origin.

The aim of this study was to investigate whether EEG source localization in the frequency domain, using the FFT dipole approximation (Lehmann, D. and Michel, C.M. Electroenceph. clin. Neurophysiol., 1990, 76: 271-276), would be useful for quantifying the frequency content of epileptic seizure activity. Between one and 7 extracranially recorded seizures were analyzed in each of 7 patients with mesolimbic epilepsy, who were seizure-free after temporal lobe resection. The full scalp frequency spectrum for the first 4 s after seizure onset, as well as for subsequent periods, was determined. Power peaks in the spectra were identified, and an instant dipole fit was performed for the frequencies corresponding to these peaks. Ictal frequencies, ranging between 3.5 and 8.5 Hz, showed a variable degree of stability over time in the different patients. For a particular frequency, dipole results were similar during the different phases of seizure development. In patients with more than one prominent frequency, dipole results for the different frequencies were similar. Dipole results were also similar between patients. We conclude that dipole localization of dominant frequencies, as obtained from full scalp FFT analysis, gives quite reproducible results for seizures originating in the mesial temporal area. The method may become a useful tool for the pre-surgical identification of patients with mesolimbic epilepsy.

Adult↗

PubMed2004

Resective reoperation for failed epilepsy surgery: seizure outcome in 64 patients.

OBJECTIVE: To determine the surgical outcome and factors of predictive value in patients undergoing reoperation for intractable partial epilepsy. METHODS: The authors retrospectively studied the operative outcome in 64 consecutive patients who underwent reoperation for intractable partial epilepsy. Demographic data, results of comprehensive preoperative evaluations, and the seizure and neurologic outcome after reoperation were determined. All patients were followed a minimum of 1 year subsequent to their last operative procedure. RESULTS: Fifty-three patients had two surgeries, and 11 patients had three or more operations. The first surgery involved a lesionectomy (n = 33), "nonlesional" temporal lobe resection (n = 28), and a "nonlesional" extratemporal resection (n = 3). The mean duration between the first and second procedure was 5.5 years. Fifty-five patients underwent an intralobar reoperation, whereas nine had a resection of a different lobe. After reoperation, 25 patients (39%) were free of seizure, 6 patients (9%) had rare seizures, 12 patients (19%) had a worthwhile improvement, and 21 patients (33%) failed to respond to surgery. Predictors of seizure-free outcome were age at seizure onset >15 years (p = 0.01), duration of epilepsy < or =5 years at the time of initial surgery (p = 0.03), and focal interictal discharges in scalp EEG (p = 0.03). Using a logistic regression model, two significant predictors emerged: duration of epilepsy < or =5 years (odds ratio, 3.18; p = 0.04) and preoperative focal interictal discharge (odds ratio, 4.45; p = 0.02). Complications of reoperation included visual field deficits (n = 9), wound infection (n = 2), subdural hematoma (n = 1), and hemiparesis (n = 1). CONCLUSION: Reoperation may be an appropriate alternative form of treatment for selected patients with intractable partial epilepsy who fail to respond to initial surgery.

Adolescent↗

PubMed1997

Surgical treatment of focal epilepsy in children: results in 37 patients.

This report concerns 37 children and teenagers operated upon for intractable seizures between 1990 and 1994. Follow-up is at least 3 years. Fourteen children underwent pure temporal lobe resections; 71% are seizure free, and 93% have a better than 90% decrease in seizure frequency. The presence of a lesion on magnetic resonance imaging, the side of the lesion, or the presence of abnormal pathology had no influence on the result of resection. 28% of the children who had extratemporal resections are seizure free, and 83% have a greater than 90% decrease in seizure frequency. There was a trend to better results in those with a lesion on magnetic resonance imaging. In the small group with temporal plus extratemporal foci, the results were poor with only 60% showing a greater than 90% reduction in seizure frequency.

Adolescent↗

PubMed2006

Is there any correlation between severity of epilepsy and cognitive abilities in patients with temporal lobe epilepsy?

Frequent refractory seizures may cause cognitive deterioration when they present at an early age, especially in infants. The findings of previous studies designed to examine the impact of repetitive seizures on cognition in adolescents and adults, however, have shown wide variation. We analyzed the data of neuropsychological evaluations of patients before they underwent temporal lobe resection because of refractory seizure disorder in our institution from 1998 to 2001. Forty-four consecutive patients aged 12-48 years underwent a comprehensive neuropsychological evaluation that included a battery of selected visual and verbal memory tests. Statistical analysis revealed no significant correlation between disease-related parameters, such as age of onset, duration of active disease, estimated cumulative number of complex partial seizures and secondarily generalized seizures, and the results of neuropsychological tests. These findings support the hypothesis that factors other than repetitive seizures are responsible for cognitive dysfunction among adolescents and adults.

Adolescent↗

PubMed2003

Pre- and postoperative intracarotid amytal procedure: an assessment of validity.

The intracarotid amytal procedure (IAP) was used twice to assess the suitability of three male patients for two successive neurosurgical procedures to relieve intractable temporal lobe epilepsy. First an amygdalohippocampectomy was performed, then further tissue was removed in a temporal lobe resection because their seizures had failed to remit. Repetition of the IAP following amygdalohippocampectomy when there was a known excision allowed inferences to be made regarding its validity in assessing lateralization of language functioning, memory functioning, and lateralization of seizure focus. The procedure was found to be reliable in assessing both language dominance and adequacy of memory functioning of the hemisphere contralateral to the lesion site. The procedure's third function of lesion lateralization was valid for identifying the known neurosurgical lesion. However, it was less successful in corroborating the lateralization of seizure focus before amygdalohippocampectomy. Differences in cognitive outcome between the two neurosurgical procedures are discussed.

Adult↗

PubMed1996

HIV-1 infection of cultured human adult oligodendrocytes.

The mechanism through which HIV-1 causes HIV dementia (HIVD) is not well understood. Myelin pallor is a common pathological finding in HIVD and could be explained by a direct infection of oligodendrocytes or interaction with HIV-1 gp 120. To determine if oligodendrocytes could be infected by HIV-1, we purified oligodendrocytes from adult human brain tissues obtained from temporal lobe resections. These cells were exposed to HIV-1 and infectivity was assayed by detection of p24gag antigen, PCR amplification, and cocultivation with CD4+ cells. These results indicate that HIV-1(IIIB and BaL) and one of four primary isolates tested can infect oligodendrocytes, resulting in the production of infectious virus. Furthermore, in an experiment that mimics a potential in vivo scenario, infected microglia were able to transmit virus to oligodendrocytes in a trans-well culture system. These experiments indicate that oligodendrocyte infection should be considered in studying the pathophysiology of HIVD.

Adult↗

PubMed2006

Long-term outcomes in epilepsy surgery: antiepileptic drugs, mortality, cognitive and psychosocial aspects.

Assessment of long-term outcomes is essential in brain surgery for epilepsy. Little information exists on long-term non-seizure outcomes after epilepsy surgery. We perform a systematic review and meta-analysis of the evidence on this topic. Our aim was to provide evidence-based estimates of antiepileptic drug, psychosocial, neuropsychological and mortality long-term outcomes following epilepsy surgery, and to identify sources of variation in published results. We searched Medline, Index Medicus, the Cochrane database, bibliographies of reviews, original articles, and book chapters, to identify articles published from 1991 to 2005, containing > or =20 patients of any age, undergoing resective or non-resective epilepsy surgery, and followed for a mean/median of > or =5 years. Two reviewers independently assessed study eligibility and extracted data, resolving disagreements through discussion. Standard meta-analytical techniques were used to pool data. Of the 159 potentially eligible articles reviewed in full-text, 35 (22%) fulfilled eligibility criteria; 6 (17%) were controlled studies; 15 (36%) explored antiepileptic drug outcome; 6 (17%) explored mortality; 11 (31%) reported psychosocial outcomes; and 7 (20%) explored neuropsychological outcomes. On an average, 14% [95% confidence interval (CI(95)) = 11-17] of the patients with temporal lobe surgery achieved long-term antiepileptic drug (AED) discontinuation, 50% (CI(95) = 45-55) achieved monotherapy, and 33% remained on polytherapy (CI(95 =) 29-38). In analyses including all types of surgery, on average, 20% (CI(95) = 18-23) achieved long-term AED discontinuation, while 41% (CI(95) = 37-45) were on monotherapy and 31% (CI(95) = 27-35) remained on polytherapy. Children achieved better AED outcomes than adults. Seizure freedom after surgery was associated with lower mortality, but inconsistent mortality outcomes precluded making strong inferences. Non-controlled studies consistently reported improved long-term psychosocial outcomes, but the effect was less clear in controlled studies. Intelligence was unchanged by surgery, but long-term memory outcomes were associated with seizure freedom and side of temporal lobe resection. Few long-term, controlled studies exist. Longer follow-up was associated with lower rates of AED discontinuation, reflecting lower seizure-free rates over time. Cognitive and psychosocial outcomes were similar to those of short-term studies, and the results were influenced by the presence of controls.

Anticonvulsants↗

PubMed1976

Temporal lobe epilepsy. Etiological factors and surgical results.

Seventy-four patients with temporal lobe epilepsy, resistant to medication, who in 1960-1969 underwent unilateral temporal lobe resection at Rigshospitalet, Copenhagen. In only 12 patients was no etiological factor found. In three-quarters of the patients a peri- or postnatal injury was the suspected etiology of the epilepsy; and in one-third, a history of complications in the actual and/or abnormal outcome of a previous pregnancy was recorded. Only seven patients had experienced febrile convulsions. Patients with certain combinations of etiological factors, including encephalitis, have a poor prognosis regarding relief from seizures. Patients in whom an abnormal outcome of the mother's previous pregnancies is recorded have a poor prognosis as regards psychiatric normalization. Apart from this no correlation has been found between the surgical results and the numbers or types of the various etiological factors.

Birth Injuries↗

PubMed2006

Hippocampal electrical stimulation in mesial temporal lobe epilepsy.

BACKGROUND: Adjustable, reversible therapies are needed for patients with pharmacoresistant epilepsy. Electrical stimulation of the hippocampus has been proposed as a possible treatment for mesial temporal lobe epilepsy (MTLE). METHODS: Four patients with refractory MTLE whose risk to memory contraindicated temporal lobe resection underwent implantation of a chronic stimulating depth electrode along the axis of the left hippocampus. The authors used continuous, subthreshold electrical stimulation (90 microsec, 190 Hz) and a double blind, multiple cross-over, randomized controlled design, consisting of three treatment pairs, each containing two 1-month treatment periods. During each treatment pair the stimulator was randomly turned ON 1 month and OFF 1 month. Outcomes were assessed at monthly intervals in a double blind manner, using standardized instruments and accounting for a washout period. The authors compared outcomes between ON, OFF, and baseline periods. RESULTS: Hippocampal stimulation produced a median reduction in seizures of 15%. All but one patient's seizures improved; however, the results did not reach significance. Effects seemed to carry over into the OFF period, and an implantation effect cannot be ruled out. The authors found no significant differences in other outcomes. There were no adverse effects. One patient has been treated for 4 years and continues to experience substantial long-term seizure improvement. CONCLUSION: The authors demonstrate important beneficial trends, some long-term benefits, and absence of adverse effects of hippocampal electrical stimulation in mesial temporal lobe epilepsy. However, the effect sizes observed were smaller than those reported in non-randomized, unblinded studies.

Adult↗

PubMed1999

Measured increase in intracellular Ca(2+) during stimulated release of endogenous glutamate from human cerebrocortical synaptosomes.

Presynaptic terminals (synaptosomes) prepared from guinea pig and rat cerebral cortex release endogenous glutamate in a Ca(2+)-dependent manner in response to membrane depolarisation. In the present study, synaptosomes were prepared from human cerebral cortex removed in association with temporal lobe resections in epileptic patients. The cytosolic free Ca(2+) concentration increased from 474+/-66 before to 649+/-89 nM after 2 min depolarisation. The basal level of free cytosolic Ca(2+) is higher and the increase in response to depolarisation is more pronounced in human synaptosomes than observed in animal experiments. The Ca(2+)-dependent glutamate release, estimated as the difference between total - and the Ca(2+)-independent glutamate release, increased from 0 to 5.4+/-1.9 nmol/mg protein. The released amount of glutamate is larger than reported in animal models. These results demonstrate that membrane depolarisation of synaptosomes from human brain evokes a rapid rise in cytosolic free Ca(2+) and a more prolonged rise in synaptic, Ca(2+)-dependent glutamate release.

4-Aminopyridine↗

PubMed2003

Surgical treatment of temporal lobe epilepsy with interictal psychosis: results of six cases.

We describe the postsurgical outcome of six patients with medically intractable temporal lobe epilepsy and interictal psychosis who underwent temporal lobe resection. All patients were submitted to a comprehensive presurgical investigation, including prolonged video-EEG monitoring. Despite their psychotic disorders, all patients were able to provide informed consent and we were able to complete the investigation of all cases. Surgical complications occurred in two cases. Seizure outcome was Engel class I (free from incapacitating seizures) in all except one patient. There was no worsening of their psychoses. Until now, there has been relative improvement in the mental conditions of five patients. Although psychosis has been considered by some authors as a contraindication to epilepsy surgery, with appropriate psychiatric intervention, patients with refractory epilepsy and chronic interictal psychosis may be submitted to prolonged presurgical investigation and undergo surgery successfully.

Adult↗

PubMed2004

Resective surgery for intractable focal epilepsy in patients with low IQ: predictors for seizure control and outcome with respect to seizures and neuropsychological and psychosocial functioning.

PURPOSE: To investigate possible predictive factors for seizure control in a group of children and adults with low IQs (IQ, < or =70) who underwent resective surgery for intractable focal epilepsy and to study outcome with respect to seizures and neuropsychological functioning. We also studied psychosocial outcome in the adult patients. METHODS: Thirty-one patients (eight children younger than 18 years) with a Wechsler Full Scale IQ of 70 or less underwent comprehensive neuropsychological assessments before and 2 years after surgery. Adults also completed the Washington Psychosocial Seizure Inventory (WPSI). Univariate analyses were used to identify variables differentiating between patients who became seizure free and those who did not. Pre- and postoperative test results were compared by t test for dependent samples. RESULTS: Forty-eight percent of the patients became seizure free, 52% of those with temporal lobe resection and 38% of those with extratemporal resection. Only one variable was predictive for seizure outcome: duration of epilepsy. In one third of the patients, who had the shortest duration of epilepsy (<12 years), 80% became seizure free. Significant improvement was seen regarding vocational adjustment in adults (WPSI). Seizure-free adults improved their Full Scale IQ scores. No cognitive changes were found in seizure-free children or in patients who did not become seizure free. CONCLUSIONS: A good seizure outcome was obtained after resective surgery in patients with intractable focal epilepsy and low IQ, provided that treatment was done relatively shortly after onset of epilepsy. No adverse effects were seen on cognitive and psychosocial functioning.

Adolescent↗