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Results for “Temporal Lobe Resection”

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PubMed2004

Cognitive changes after epilepsy surgery in the posterior cortex.

OBJECTIVE: The relationship between the posterior cortex and cognitive functions is still a relatively open field. There are no studies on populations in which functions of posterior structures were examined by a standardised neuropsychological examination before and after posterior resections. Changes in cognitive performance are regularly observed after epilepsy surgery in the temporal lobe. However, information about neuropsychological impairments after resections in the posterior cortex is poor, owing to the relatively low proportion of cortical resections in this area. METHODS: We retrospectively studied changes in cognition in the neuropsychological data of 28 patients prior to and 6 months after posterior cortical resections. RESULTS: Cognition significantly showed differences in performance intelligence quotient compared with verbal intelligence quotient. Post-operative verbal intelligence consistently increased, whereas performance intelligence decreased. There was no effect regarding the lesion side, continuation of seizures, or reduction of visual field after surgery. Epilepsy surgery in this area did not lead to significant differences in general intelligence after surgery. CONCLUSION: Functions of posterior areas could be described by standardised neuropsychological measures. Posterior regions contribute to explicit attentional and visuoconstructional abilities. Epilepsy surgery in the posterior cortex bears no risk for substantial decline in general cognition although some discrete impairment in performance intelligence may occur.

Adolescent↗

PubMed2005

Treatment options and paradigms in childhood temporal lobe epilepsy.

Temporal lobe epilepsy in adults is a relatively homogenous syndrome with hippocampal sclerosis being its most common pathologic substrate. In the pediatric age group, low-grade neoplasms and cortical dysplasia are much more common than hippocampal sclerosis. Pediatric temporal lobe epilepsy has distinct semiologic, electrophysiologic and imaging characteristics as compared with its adult counterpart. The various treatment options for pediatric temporal lobe epilepsy include antiepileptic drugs, resective surgery, vagal nerve stimulation and the ketogenic diet. In spite of the multiple antiepileptic drugs currently available, 5-10% of all newly diagnosed cases will remain intractable to medical therapy and should be referred for presurgical evaluation. Resective surgery offers the best chance of seizure freedom in carefully selected patients. Future areas of research include new drug development, better imaging and localization techniques, and brain stimulation.

Anticonvulsants↗

PubMed2005

The subiculum: a potential site of ictogenesis in human temporal lobe epilepsy.

PURPOSE: This study determines synaptic and intrinsic alterations of subicular pyramidal cells that are associated with activity recorded in patients suffering from temporal lobe epilepsy. METHODS: Electroencephalograms with sphenoidal electrodes were correlated with in vitro single cell recordings of subicular pyramidal cells from the corresponding resected epileptic tissue. We determined alterations of synaptic and intrinsic properties of subicular pyramidal cells that accompany spontaneous rhythmic activity in human sclerotic and nonsclerotic epileptic tissue. RESULTS: We found that in sclerotic, but also in nonsclerotic hippocampal tissue, the subiculum showed cellular and synaptic changes that were associated with spontaneous rhythmic activity correlated to the occurrence and frequency of interictal discharges recorded in the electroencephalograms of the corresponding patients. CONCLUSIONS: Even though Ammon's horn sclerosis (AHS) in resected hippocampi from patients suffering from temporal lobe epilepsy has important prognostic implications for freedom from seizures postoperatively, we report here that both synaptic and intrinsic alterations enhance seizure susceptibility of the subiculum also in the absence of classical AHS.

Adult↗

PubMed1996

Temporal lobe arteriovenous malformations: surgical management and outcome.

BACKGROUND: Temporal lobe arteriovenous malformations (AVMs) represent a subgroup of intracranial AVMs with particular characteristics and management issues. METHODS: We performed a retrospective analysis of 24 consecutive patients with temporal lobe AVMs treated with surgical excision. Factors such as location, size, arterial feeders, venous drainage, and clinical follow-up were recorded for each. Results were compared with those of 132 patients with nontemporal lobe AVMs surgically treated over the same time period. RESULTS: Sixteen of the temporal AVMs were located in the convexity, six in the mesotemporal region, and two were predominantly intraventricular. The mode of presentation was seizure in 11 patients, hemorrhage in 7, headache in 4, and 2 were asymptomatic. Patients with convexity AVMs more commonly presented with seizures, whereas patients with mesotemporal or intraventricular AVMs were more likely to present with hemorrhage. One patient with subarachnoid hemorrhage from a basilar artery aneurysm died. Postoperatively, 2 patients (8.3%) had a new hemiparesis and dysphasia, 1 (4%) had a new dysphasia and hemianopsia, and 3 others (13%) were left with an isolated superior quadrant field deficit. Lasting surgical morbidity other than isolated field deficit was 13% for patients with temporal AVMs and 15% for those with nontemporal AVMs. CONCLUSIONS: Temporal lobe AVMs may be successfully resected using a direct microsurgical approach with limited morbidity and excellent prognosis for recovery. Most of the deficits relating to AVM hemorrhage and those of the immediate postoperative period improved significantly over the subsequent few months.

Adolescent↗

PubMed2005

Up-regulation of hippocampal metabotropic glutamate receptor 5 in temporal lobe epilepsy patients.

Metabotropic glutamate receptors (mGluRs) are G protein-coupled receptors involved in the regulation of glutamatergic transmission. Recent studies indicate that excitatory group I mGluRs (mGluR1 and mGluR5) contribute to neurotoxicity and hyperexcitability during epileptogenesis. In this study, we examined the distribution of mGluR1alpha and mGluR5 immunoreactivity (IR) in hippocampal resection tissue from pharmaco-resistant temporal lobe epilepsy (TLE) patients. IR was detected with panels of receptor subtype specific antisera in hippocampi from TLE patients without (non-HS group) and with hippocampal sclerosis (HS group) and was compared with that of non-epileptic autopsy controls (control group). By immunohistochemistry and immunoblot analysis, we found a marked increase of mGluR5 IR in hippocampi from the non-HS compared with the control group. High mGluR5 IR was most prominent in the cell bodies and apical dendrites of hippocampal principal neurons and in the dentate gyrus molecular layer. In the HS group, this increase in neuronal mGluR5 IR was even more pronounced, but owing to neuronal loss the number of mGluR5-immunoreactive neurons was reduced compared with the non-HS group. IR for mGluR1alpha was found in the cell bodies of principal neurons in all hippocampal subfields and in stratum oriens and hilar interneurons. No difference in mGluR1alpha IR was observed between neurons in both TLE groups and the control group. However, owing to neuronal loss, the number of mGluR1alpha-positive neurons was markedly reduced in the HS group. The up-regulation of mGluR5 in surviving neurons is probably a consequence rather than a cause of the epileptic seizures and may contribute to the hyperexcitability of the hippocampus in pharmaco-resistant TLE patients. Thus, our data point to a prominent role of mGluR5 in human TLE and indicate mGluR5 signalling as potential target for new anti-epileptic drugs.

Adult↗

PubMed2002

Standardization of amygdalohippocampectomy with intraoperative magnetic resonance imaging: preliminary experience.

PURPOSE: Intraoperative magnetic resonance imaging (IMRI) is an extremely useful neurosurgical tool in surgeries in which the extent of resection is known to have a significant impact on outcome. Residual hippocampus is the most common cause of recurrent seizures after temporal lobectomy for medial temporal lobe epilepsy. Although the risk/benefit ratio of a policy of universal radical hippocampal resection is not known, we hypothesized that IMRI would aid in the intraoperative assessment of the extent of hippocampal resection and assist in accomplishing a complete hippocampectomy. METHODS: Five consecutive patients with medically intractable medial temporal lobe epilepsy underwent a radical amygdalohippocampectomy as part of the their surgery for epilepsy. IMRI was used before surgery and after an initial resection. The quality of images was assessed. Postoperative MR images were evaluated by a radiologist to determine the extent of resection of the amygdala, hippocampus, and parahippocampal gyrus. RESULTS: There were no perioperative infections. After a mean follow-up of 10 months, all patients are seizure free. T(1)-weighted coronal intraoperative images were judged adequate at visualizing the medial structures in all patients. T(2) and fluid-attenuated inversion recovery (FLAIR) images did not provide useful information. Postoperative MR images indicated that a complete hippocampectomy had been achieved in all patients. CONCLUSIONS: IMRI is a useful adjunct in the surgical treatment of medial temporal lobe epilepsy and perhaps the most reliable method of standardizing a complete hippocampectomy. T(1)-weighted coronal images are the most helpful sequence.

Adolescent↗

PubMed2000

Remote discharges in the posterior language area during basal temporal stimulation.

A 23-year-old woman with refractory complex partial seizures underwent implantation of subdural grid electrodes over the left hemisphere to map epileptic foci and language function. Aphasic symptoms occurred during stimulation of the basal temporal area, which were always associated with intrastimulus remote discharges (ISRDs) in the classical posterior language area. No sequential language deficits occurred after anterior temporal lobectomy including the basal temporal area. These results suggest a close functional relationship between the basal temporal area and posterior language area in patients with temporal lobe epilepsy. ISRDs may explain the paradoxical observation that resection of the basal temporal language area results in no language deficits.

Adult↗

PubMed1991

Temporal lobectomy in patients with bitemporal epilepsy defined by depth electroencephalography.

Patient selection for temporal lobectomy was reviewed for 23 patients with seizures that arose independently from each temporal lobe as detected by depth electroencephalography (EEG). Although neuropsychological testing, interictal EEG findings, imaging studies, and subclinical seizures were also considered, all patients offered temporal lobectomy had (1) at least 50% of the clinical seizures originating from the lobe to be resected, (2) adequate contralateral memory on testing with amobarbital, and (3) no clear evidence of an extratemporal focus. Eleven patients underwent temporal lobectomy. Pathological findings were considered positive in all nine specimens reviewed. Nine patients had no seizures, one had greater than 75% reduction in seizure frequency, and 1 had 50 to 75% reduction. Pathological features and clinical outcome were similar in the 6 patients with fewer than 80% and the 5 patients with at least 80% of seizures originating from the resected lobe. Thus, having fewer than 80% of seizures originate from one temporal lobe should not be an absolute contraindication for temporal lobectomy.

Adolescent↗

PubMed1987

Brain tumors presenting as a seizure disorder in infants.

Seizures occur in 25% to 40% of children with supratentorial tumors and are the presenting complaint in 10% to 15%. However, when divided by age, only 2% of children with seizures as the presenting complaint of brain tumors were less than 1 year of age. Three children, ranging in age from 20 days to 7 months and seen within the past 2 years, form the basis of this report. The presenting complaint in all children was seizures. Computed tomographic (CT) scan was indicated in all children because of intractability to anticonvulsant drug therapy (one patient) and focal electroencephalographic (EEG) abnormality with clinical evidence of complex partial seizure activity (two patients). CT scan showed a contrast-enhancing mass in the medial temporal lobe in all patients. At surgery, a temporal lobe tumor was found and resected in all children. Histopathologic examination revealed a ganglioglioma, a fibrillary astrocytoma, and an anaplastic astrocytoma. All children did well postoperatively and are seizure free to date. Our experience suggests that supratentorial tumors should be considered as a cause of intractable and/or focal seizures in children under 1 year of age, and that such tumors should be attacked aggressively neurosurgically. Our experience is also in agreement with that of Tadmor et al, who have suggested that with the advent of CT scanning supratentorial tumors in this age group have been found to be more common than previously realized.

Astrocytoma↗

PubMed1989

Axonal regeneration on mature human brain tissue sections in culture.

Fresh frozen sections of the temporal lobe from patients undergoing surgical resection for the control of epilepsy were used as a substrate in tissue culture to test for neurite growth-promoting activity. Robust neurite growth from ganglia of embryonic chicks was observed on gray matter regions of the sections and little growth was observed on white matter regions. These results indicate that the dichotomy between gray and white matter regions of the mature central nervous system in supporting neurite growth is present in human brain tissue and supports the general hypothesis that white matter in the mature central nervous system inhibits neurite regeneration but that gray matter will support neurite growth.

Animals↗

PubMed2006

Anomalous levels of Cl- transporters in the hippocampal subiculum from temporal lobe epilepsy patients make GABA excitatory.

The mRNA levels of NKCC1, an inwardly directed Na(+), K(+)-2Cl(-) cotransporter that facilitates the accumulation of intracellular Cl(-), and of KCC2, an outwardly directed K(+)-Cl(-) cotransporter that extrudes Cl(-), were studied in surgically resected brain specimens from drug-resistant temporal lobe (TL) epilepsy (TLE) patients. Quantitative RT-PCR analyses of the mRNAs extracted from the human TLE-associated brain regions revealed an up-regulation of NKCC1 mRNA and a down-regulation of KCC2 mRNA in the hippocampal subiculum, compared with the hippocampus proper or the TL neocortex, suggesting an abnormal transcription of Cl(-) transporters in the TLE subiculum. In parallel experiments, cell membranes isolated from the same TLE-associated brain regions were injected into Xenopus oocytes that rapidly incorporated human GABA(A) receptors into their surface membrane. The GABA currents elicited in oocytes injected with membranes from the subiculum had a more depolarized reversal potential (E(GABA)) compared with the hippocampus proper or the neocortex. The NKCC1 blocker bumetanide or a temperature decrease of 10 degrees C shifted the GABA-current E(GABA) more negative in oocytes injected with membranes from TLE hippocampal subiculum, matching the E(GABA) of TL neocortex-injected oocytes. We conclude that the anomalous expression of both Cl(-) transporters, NKCC1 and KCC2 [corrected] in TLE hippocampal subiculum probably causes altered Cl(-) transport in the "epileptic" neurons, as revealed in the microtransplanted Xenopus oocytes, and renders GABA aberrantly "exciting," a feature that may contribute to the precipitation of epileptic seizures.

Animals↗

PubMed2004

Memory outcome after selective amygdalohippocampectomy in patients with temporal lobe epilepsy: one-year follow-up.

PURPOSE: In a previous study we reported clinically significant memory declines 3 months after selective amygdalohippocampectomy (SAH) in 140 patients with mesial temporal lobe epilepsy, particularly if the resection was left-sided. We supposed that the observed postoperative impairments might have reflected acute effects of surgery. Therefore we evaluated in the present study whether a recovery can be found 1 year after surgery. METHODS: Verbal and nonverbal memory functions were assessed in 115 patients before and 3 and 12 months after unilateral SAH. RESULTS: No recovery of postoperative verbal memory declines was found in the left-SAH group. Clinically meaningful losses were still evident in 33 to 50% of patients. In right-SAH patients, a recovery of verbal memory was indicated, and effects of surgical complications were no longer evident. One year after surgery, the corresponding preoperative performance was the only significant predictor of a postoperative change in the left-SAH group. CONCLUSIONS: Verbal memory decline observed 3 months after left SAH is persistent 1 year after surgery. Declines in verbal memory, which were observed in some right-SAH patients at the short-term follow-up, seem to be temporary.

Adult↗

PubMed1993

Lateral temporal polar approach to mesial temporal lesions.

A newly developed lateral temporal polar surgical approach to the mesiobasal temporal region was applied to 25 consecutive patients with mesially confined temporal lobe lesions. This approach is characterized by a very limited resection of the lateral temporal cortex and a direct approach to the uncal area. The advantages of this method are clear orientation to the mesial temporal structures, easy access to the posteromesial part of the temporal lobe, and preservation of functionally important structures, such as the lateral temporal speech area, optic radiation, and temporal stem. Details of the surgical procedure are described.

Epilepsy, Temporal Lobe↗

PubMed1988

[Metastatic brain tumor originating from the cardiac sarcoma].

A 39-year-old woman had suddenly onset of headache, aphasia and right hemiparesis. CT scan revealed a mass lesion in the left parieto-temporal lobe. The brain tumor was resected twice. But, heart tumor could not be resected because congestive heart failure progressed rapidly. At last, she succumbed to systemic metastasis at 4 months after the onset of symptoms. At autopsy, tumors were found to be localized in left atrium of the heart, left parietal lobe, bilateral occipital lobe of the brain, pancreas, liver and stomach. Histological examination was diagnosed as a malignant-fibrous-histiocytoma. Review of the literature reveals no other case with cerebral metastasis of malignant-fibrous-histiocytoma.

Adult↗

PubMed2005

Surgical management of temporal lobe tumor-related epilepsy in children.

OBJECT: Slow-growing, low-grade temporal lobe tumors are one of the most common causes of epilepsy in children. Although there are numerous consistent features in this patient group, consensus about the management and surgical approach is lacking. In this study the authors review the clinical, pathological, and radiological features as well as outcome data obtained in 29 pediatric patients with temporal lobe tumor-related epilepsy and discuss the surgical treatment strategies. METHODS: In patients who presented with intractable seizures secondary to mass lesions and underwent comprehensive epilepsy workup, the tumor was resected and the diagnosis confirmed by pathological examination. A minimum follow-up period of 16 months was required. Medical records were reviewed for details of seizure type and duration, electrophysiological data, imaging studies, operative notes, pathological examination reports, and follow-up data. The surgical approach was as follows. The lesionectomy with/without cortical resection was performed in all cases of lateral temporal tumors. Lesionectomy was performed with/without cortical resection in cases of basal temporal tumors if the mesial structures were radiologically normal. Mesial temporal tumors were excised, as were the remaining mesial temporal structures in the nondominant hemisphere; however, if the tumor was in the dominant hemisphere, lesionectomy was performed only if the remaining mesial structures were radiologically normal. Twenty-nine patients between 2 and 18 years of age were identified. Most tumors were located in the mesial temporal lobe. All patients underwent resection of the tumor with or without mesial and cortical structures. The most common pathological entity was dysembryoplastic neuroepithelial tumor. Sixty-nine percent of the patients remained seizure free (Engel Class I) and 14% experienced significant improvement (Engel Class II) after surgery. Outcome was better in the patients who underwent gross-total tumor resection. CONCLUSIONS: Mesially located low-grade neoplasms were the most frequently observed mass lesions in children with temporal tumor-related epilepsy in this series. Resection of the tumor with or without amygdalohippocampectomy provides a high rate of seizure-free outcome. It is the author's opinion that temporal lobe tumors should be managed based on the subgroups defined by their anatomical locations. If the tumor is located in or in proximity to eloquent cortex, we recommend functional magnetic resonance imaging and invasive monitoring techniques to map the eloquent cortex and epileptogenic zone, thereby tailoring the resection.

Adolescent↗

PubMed2005

Medically refractory epilepsy associated with temporal lobe ganglioglioma: characteristics and postoperative outcome.

OBJECTIVES: To define the postoperative seizure outcome and its predictors in patients with ganglioglioma-related temporal lobe epilepsy (TLE). PATIENTS AND METHODS: We reviewed the pre- and post-surgical evaluation data of 23 patients with temporal lobe ganglioglioma, who had completed >or=1 year of postoperative follow-up. They comprised 4.9% of the patients with TLE and 67.6% of the tumoral TLE operated in a developing country epilepsy center during an 8-year period. RESULTS: Median age at surgery was 20 years; median duration of epilepsy prior to surgery was 9 years. Magnetic resonance imaging (MRI) revealed tumor in mesial temporal location in 18 patients (78.3%) and in the lateral location in 2; in the remaining 3, involved both mesial and lateral regions. EEG abnormalities were localized to the side of lesion in the majority. Mesial temporal lobe structures were included in the resection, if they were involved by the tumor; otherwise, lesionectomy alone was performed. During a median follow-up of 4 years, 19 (82.6%) patients were completely seizure-free. Epileptiform abnormalities persisting in the 1-year postoperative EEG predicted unfavorable seizure outcome. CONCLUSION: We emphasize that, in patients with temporal lobe ganglioglioma, when the seizures are medically refractory, surgery offers potential for cure of epilepsy in the majority.

Adolescent↗

PubMed1999

Entorhinal cortex in temporal lobe epilepsy: a quantitative MRI study.

BACKGROUND: The entorhinal cortex (EC) is a distinct anatomic and functional region of the anterior parahippocampal gyrus, which plays a role in seizure generation and propagation in temporal lobe epilepsy (TLE). In tissue resected from TLE patients, cell loss in the EC has been described. OBJECTIVES: To develop a standardized protocol for identifying the anatomic boundaries of the EC using high-resolution MRI and to examine morphologic changes of the EC in TLE. METHODS: We performed T1-weighted MRIs in 20 patients (7 males) with TLE (mean age 34 years) and 18 normal controls (mean age 26 years). Eleven patients had a left and 9 a right epileptic focus as defined by history, video-EEG, and surgical outcome. The volumes of the EC, the hippocampus, and the amygdala were measured using a standardized MRI protocol. Analysis of variance (ANOVA) was used to examine the effect of seizure focus lateralization and hemisphere on these volumes. An asymmetry ratio [A (%) = 100 x (R-L)/(R+L)/2] was also compared between groups using ANOVA. RESULTS: In normal controls the volume of the right EC was 1,247 +/- 127 mm3 (mean +/- standard deviation), and that of the left EC was 1,215 +/- 135 mm3 (p > 0.05). We found a bilateral reduction in the volume of the EC in TLE patients compared with controls (p < 0.05). Examination of the asymmetry ratios showed that the reduction in volume of the EC was greater ipsilateral to the epileptic focus (p < 0.05). The volumes of the hippocampus and the amygdala were smaller on the side of the focus in TLE patients compared with controls (p < 0.05). CONCLUSIONS: With a standardized protocol for the quantitative assessment of the EC, patients with unilateral TLE show bilateral reduction in the volume of the EC. However, this reduction is more severe ipsilateral to the epileptic focus.

Adolescent↗

PubMed2003

Diffusion parameters of the extracellular space in human gliomas.

Tumor cell migration through the extracellular space (ECS) might be affected by its pore size and extracellular matrix molecule content. ECS volume fraction alpha (alpha = ECS volume/total tissue volume), tortuosity lambda (lambda(2) = free/apparent diffusion coefficient) and nonspecific uptake k' were studied by the real-time tetramethylammonium method in acute slices of human tissue. The diffusion parameters in temporal cortical tissue resected during surgical treatment of temporal lobe epilepsy (control) were compared with those in brain tumors. Subsequently, tumor slices were histopathologically classified according to the grading system of the World Health Organization (WHO), and proliferative activity was assessed. The average values of alpha, lambda, and k' in control cortex were 0.24, 1.55, and 3.66 x 10(-3)s(-1), respectively. Values of alpha, lambda, and k' in oligodendrogliomas did not significantly differ from controls. In pilocytic astrogliomas (WHO grade I) as well as in ependymomas (WHO grade II), alpha was significantly higher, while lambda and k' were unchanged. Higher values of alpha as well as lambda were found in low-grade diffuse astrocytomas (WHO grade II). In cellular regions of high-grade astrocytomas (WHO grade III and IV), alpha and lambda were further increased, and k' was significantly larger than in controls. Classic medulloblastomas (WHO grade IV) had an increased alpha, but not lambda or k', while in the desmoplastic type alpha and k' remained unchanged, but lambda was greatly increased. Tumor malignancy grade strongly corresponds to an increase in ECS volume, which is accompanied by a change in ECS structure manifested by an increase in diffusion barriers for small molecules.

Adolescent↗