Temporal Lobe Surgery Research Articles

Reactivation of herpes simplex virus-1 following epilepsy surgery.

PurposeThe present study reports a case of encephalitis due to herpes simplex virus-1 (HSV-1), following surgical manipulation of the site of a primary infection.MethodsHerpes simplex virus-1 infection was confirmed by CSF PCR and DNA sequencing.ResultsThe patient was an 11-year-old girl who required temporal lobe surgery for epilepsy. She had meningoencephalitis due to HSV at the age of 20 months, and she was treated with acyclovir. Three years later, the patient developed uncontrolled seizures that became more frequent and changed in character at 11 years of age. On the 12th postoperative day, she developed fever and seizures, and she was diagnosed with HSV-1 by positive CSF PCR. She was treated with acyclovir (30 mg/kg/day for 21 days). In this report, we describe the patient and review the relevant literature.ConclusionThe authors stress the potential risk of reactivation of HSV encephalitis after intracranial surgery. Herpes simplex virus encephalitis must be considered in neurosurgical patients who develop postoperative seizures and fever.

Frontal gray matter abnormalities predict seizure outcome in refractory temporal lobe epilepsy patients.

Developing more reliable predictors of seizure outcome following temporal lobe surgery for intractable epilepsy is an important clinical goal. In this context, we investigated patients with refractory temporal lobe epilepsy (TLE) before and after temporal resection. In detail, we explored gray matter (GM) volume change in relation with seizure outcome, using a voxel-based morphometry (VBM) approach. To do so, this study was divided into two parts. The first one involved group analysis of differences in regional GM volume between the groups (good outcome (GO), e.g., no seizures after surgery; poor outcome (PO), e.g., persistent postoperative seizures; and controls, N = 24 in each group), pre- and post-surgery. The second part of the study focused on pre-surgical data only (N = 61), determining whether the degree of GM abnormalities can predict surgical outcomes. For this second step, GM abnormalities were identified, within each lobe, in each patient when compared with an ad hoc sample of age-matched controls. For the first analysis, the results showed larger GM atrophy, mostly in the frontal lobe, in PO patients, relative to both GO patients and controls, pre-surgery. When comparing pre-to-post changes, we found relative GM gains in the GO but not in the PO patients, mostly in the non-resected hemisphere. For the second analysis, only the frontal lobe displayed reliable prediction of seizure outcome. 81% of the patients showing pre-surgical increased GM volume in the frontal lobe became seizure free, post-surgery; while 77% of the patients with pre-surgical reduced frontal GM volume had refractory seizures, post-surgery. A regression analysis revealed that the proportion of voxels with reduced frontal GM volume was a significant predictor of seizure outcome (p = 0.014). Importantly, having less than 1% of the frontal voxels with GM atrophy increased the likelihood of being seizure-free, post-surgery, by seven times. Overall, our results suggest that using pre-surgical GM abnormalities within the frontal lobe is a reliable predictor of seizure outcome post-surgery in TLE. We believe that this frontal GM atrophy captures seizure burden outside the pre-existing ictal temporal lobe, reflecting either the development of epileptogenesis or the loss of a protective, adaptive force helping to control or limit seizures. This study provides evidence of the potential of VBM-based approaches to predict surgical outcomes in refractory TLE candidates.

Music and its association with epileptic disorders.

The association between music and epileptic seizures is complex and intriguing. Musical processing within the human brain recruits a network which involves many cortical areas that could activate as part of a temporal lobe seizure or become hyperexcitable on musical exposure as in the case of musicogenic epilepsy. The dichotomous effect of music on seizures may be explained by modification of dopaminergic circuitry or counteractive cognitive and sensory input in ictogenesis. Research has explored the utility of music as a therapy in epilepsy and while limited studies show some evidence of an effect on seizure activity; further work is required to ascertain its clinical potential. Sodium channel-blocking antiepileptic drugs, e.g., carbamazepine and oxcarbazepine, appear to effect pitch perception particularly in native-born Japanese, a rare but important adverse effect, particularly if a professional musician. Temporal lobe surgery for right lateralizing epilepsy has the capacity to effect all facets of musical processing, although risk and correlation to resection area need further research. There is a need for the development of investigative tools of musical processing that could be utilized along the surgical pathway. Similarly, work is also required in devising a musical paradigm as part of electroencephalography to improve surveillance of musicogenic seizures. These clinical applications could aid the management of epilepsy and preservation of musical ability.

Planning for selective amygdalohippocampectomy involving less neuronal fiber damage based on brain connectivity using tractography.

Temporal lobe resection is an important treatment option for epilepsy that involves removal of potentially essential brain regions. Selective amygdalohippocampectomy is a widely performed temporal lobe surgery. We suggest starting the incision for selective amygdalohippocampectomy at the inferior temporal gyrus based on diffusion magnetic resonance imaging (MRI) tractography. Diffusion MRI data from 20 normal participants were obtained from Parkinson's Progression Markers Initiative (PPMI) database (www.ppmi-info.org). A tractography algorithm was applied to extract neuronal fiber information for the temporal lobe, hippocampus, and amygdala. Fiber information was analyzed in terms of the number of fibers and betweenness centrality. Distances between starting incisions and surgical target regions were also considered to explore the length of the surgical path. Middle temporal and superior temporal gyrus regions have higher connectivity values than the inferior temporal gyrus and thus are not good candidates for starting the incision. The distances between inferior temporal gyrus and surgical target regions were shorter than those between middle temporal gyrus and target regions. Thus, the inferior temporal gyrus is a good candidate for starting the incision. Starting the incision from the inferior temporal gyrus would spare the important (in terms of betweenness centrality values) middle region and shorten the distance to the target regions of the hippocampus and amygdala.

Epilepsy surgery in patients with bilateral temporal lobe seizures: a systematic review.

We explored the association between magnetic resonance imaging (MRI) lesion, degree of seizure laterality on intracranial electroencephalography (iEEG), and seizure outcome in patients with ambiguous or presumed bilateral temporal lobe epilepsy (BiTLE) on scalp EEG. We systematically reviewed the literature using Embase and MEDLINE up to May 31, 2012. Patients with bilateral iEEG, temporal lobe surgery, and follow-up ≥1 year were included. We undertook three separate analyses on patients whose scalp EEG showed ambiguous onset or BiTLE (1) group data of those whose iEEG demonstrated unilateral TLE, (2) group data of those whose iEEG demonstrated BiTLE, (3) individual patient analysis in those with BiTLE for whom iEEG seizure laterality data were provided. Of 1,403 patients with ambiguous or presumed BiTLE on scalp EEG, 1,027 (73%) proved to have unilateral TLE on iEEG and contributed to the first analysis. Of these, 58% had Engel class I and 9% Engel class II outcomes. Of 132 patients in the second analysis (true BiTLE), Engel class I and II outcomes were achieved in 23% and 14%, respectively. Of 41 patients in the third analysis, 66% and 2% had Engel class I and II outcomes, respectively. The median proportion of seizures ipsilateral to the resection on iEEG did not differ between BiTLE patients with Engel class I-II (76%) and Engel III-IV (78%) outcomes (p = 0.87). Patients with ambiguous or independent bitemporal seizure onset on scalp EEG achieved good surgical outcomes. Overall, a significantly higher proportion of patients achieved good outcomes when iEEG showed unilateral TLE (67%) than when it showed true BiTLE (45%). However, the degree of seizure lateralization in those with BiTLE was not associated with seizure outcome, and it has a limited role in selecting the side of surgery.

Temporal lobe surgery in childhood and neuroanatomical predictors of long-term declarative memory outcome.

The temporal lobes play a prominent role in declarative memory function, including episodic memory (memory for events) and semantic memory (memory for facts and concepts). Surgical resection for medication-resistant and well-localized temporal lobe epilepsy has good prognosis for seizure freedom, but is linked to memory difficulties in adults, especially when the removal is on the left side. Children may benefit most from surgery, because brain plasticity may facilitate post-surgical reorganization, and seizure cessation may promote cognitive development. However, the long-term impact of this intervention in children is not known. We examined memory function in 53 children (25 males, 28 females) who were evaluated for epilepsy surgery: 42 underwent unilateral temporal lobe resections (25 left, 17 right, mean age at surgery 13.8 years), 11 were treated only pharmacologically. Average follow-up was 9 years (range 5-15). Post-surgical change in visual and verbal episodic memory, and semantic memory at follow-up were examined. Pre- and post-surgical T1-weighted MRI brain scans were analysed to extract hippocampal and resection volumes, and evaluate post-surgical temporal lobe integrity. Language lateralization indices were derived from functional magnetic resonance imaging. There were no significant pre- to postoperative decrements in memory associated with surgery. In contrast, gains in verbal episodic memory were seen after right temporal lobe surgery, and visual episodic memory improved after left temporal lobe surgery, indicating a functional release in the unoperated temporal lobe after seizure reduction or cessation. Pre- to post-surgical change in memory function was not associated with any indices of brain structure derived from MRI. However, better verbal memory at follow-up was linked to greater post-surgical residual hippocampal volumes, most robustly in left surgical participants. Better semantic memory at follow-up was associated with smaller resection volumes and greater temporal pole integrity after left temporal surgery. Results were independent of post-surgical intellectual function and language lateralization. Our findings indicate post-surgical, hemisphere-dependent material-specific improvement in memory functions in the intact temporal lobe. However, outcome was linked to the anatomical integrity of the temporal lobe memory system, indicating that compensatory mechanisms are constrained by the amount of tissue which remains in the operated temporal lobe. Careful tailoring of resections for children undergoing epilepsy surgery may enhance long-term memory outcome.

Paediatric epilepsy surgery: making the best of a tough situation.

This scientific commentary refers to ‘Temporal lobe surgery in childhood and neuroanatomical predictors of long-term declarative memory outcome’ by Skirrow et al. (10.1093/brain/awu313).

Perioperative anesthetic implications of epilepsy surgery: a retrospective analysis.

Drug-resistant epilepsy (DRE) occurs in about 30% of individuals with epilepsy. For seizure control, a wide range of surgical procedures are performed, depending on the underlying pathology. To address the anesthetic and perioperative concerns in these patients, we analyzed the data of persons with DRE who underwent epilepsy surgery at our institute. A retrospective analysis of patients who underwent epilepsy surgery from 2005-2010 was performed. For data collection and analysis, patients were divided into three groups: Group I (temporal lobe epilepsy), Group II (extratemporal lobe epilepsy), and Group III (multilobar epilepsy and others). A total of 241 surgical procedures were performed on 235 persons with DRE. The procedures included temporal (149) and extratemporal (47) lobe resection, hemispherotomy (31), corpus callosotomy (5), vagus nerve stimulation (3), and implantation of invasive cerebral electrodes (6). General anesthesia was the more common anesthetic technique; awake craniotomy was performed in only five cases. Intraoperative neuromonitoring was used most frequently in Group II. Patients in Group III had the longest intraoperative course and the greatest blood loss. The overall incidence of postoperative mechanical ventilation was 17.84%, with 53.84% of patients in Group III alone. At one-year follow-up, a good outcome was seen in 78% of temporal lobe resection, 55% of extratemporal cortical resection, 82% of hemispherotomy, and 80% of corpus callosotomy procedures. Careful preoperative selection and meticulous perioperative management are the most significant factors for success of epilepsy surgery. Although temporal and extratemporal lobe surgeries have a fairly stable perioperative course, multilobar epilepsy requiring disconnective surgery poses a greater challenge.

P.3.b.032 Evaluation of preferences of chimeric, reversed and normal self-face in patients with schizophrenia and healthy controls – a pilot study

Temporal lobe epilepsy with hippocampus sclerosis (HS) is the most frequent focal epilepsy and often refractory to anticonvulsant therapy. Secondary structural damage has been reported in several studies of temporal lobe epilepsy and unilateral hippocampal sclerosis. Applying diffusion tensor imaging (DTI) we investigated alterations in white matter following temporal lobe surgery in patients with medial temporal lobe epilepsy. We examined 40 patients who underwent surgery at our hospital for HS between 1996 and 2006 with diffusion tensor imaging (DTI). Images were obtained at a 3 T MRI scanner employing 60 gradient directions. Tract-based spatial statistics (TBSS), a novel voxel-based approach, was applied to analyze the data. Both patients with left- as well as right-sided surgery exhibited widespread degradation of fractional anisotropy (FA) in main fiber tracts not limited to the respective temporal lobe such as the uncinate fasciculus, the fronto-occipital fasciculus, the superior longitudinal fasciculus, the corpus callosum and the corticospinal tract on the respective hemisphere. Patients with left-hemispheric surgery showed more widespread affections ipsilaterally and also FA decrease in the contralateral inferior longitudinal fasciculus. DTI demonstrates widespread clusters of abnormal diffusivity and anisotropy in prominent white matter tracts linking mesial temporal lobe structures with other brain areas. Alterations in the ipsilateral mesial temporal lobe can be attributed to be a result of surgery, whereas extratemporal FA decrease is more likely the result of the underlying seizure disorder.

In vivo P-glycoprotein function before and after epilepsy surgery.

Objectives:To study the functional activity of the multidrug efflux transporter P-glycoprotein (Pgp) at the blood-brain barrier of patients with temporal lobe epilepsy using (R)-[11C]verapamil (VPM)-PET before and after temporal lobe surgery to assess whether postoperative changes in seizure frequency and antiepileptic drug load are associated with changes in Pgp function.Methods:Seven patients with drug-resistant temporal lobe epilepsy underwent VPM-PET scans pre- and postsurgery. Patients were followed up for a median of 6 years (range 4–7) after surgery. Pgp immunoreactivity in surgically resected hippocampal specimens was determined with immunohistochemistry.Results:Optimal surgical outcome, defined as seizure freedom and withdrawal of antiepileptic drugs, was associated with higher temporal lobe Pgp function before surgery, higher Pgp-positive staining in surgically resected hippocampal specimens, and reduction in global Pgp function postoperatively, compared with nonoptimal surgery outcome.Conclusions:The data from our pilot study suggest that Pgp overactivity in epilepsy is dynamic, and complete seizure control and elimination of antiepileptic medication is associated with reversal of overactivity, although these findings will require confirmation in a larger patient cohort.

Epilepsy surgery failure in children: a quantitative and qualitative analysis.

Resection is a safe and effective treatment option for children with pharmacoresistant focal epilepsy, but some patients continue experience seizures after surgery. While most studies of pediatric epilepsy surgery focus on predictors of postoperative seizure outcome, these factors are often not modifiable, and the reasons for surgical failure may remain unclear. The authors performed a retrospective cohort study of children and adolescents who received focal resective surgery for pharmacoresistant epilepsy. Both quantitative and qualitative analyses of factors associated with persistent postoperative seizures were conducted. Records were reviewed from 110 patients, ranging in age from 6 months to 19 years at the time of surgery, who underwent a total of 115 resections. At a mean 3.1-year follow-up, 76% of patients were free of disabling seizures (Engel Class I outcome). Seizure freedom was predicted by temporal lobe surgery compared with extratemporal resection, tumor or mesial temporal sclerosis compared with cortical dysplasia or other pathologies, and by a lower preoperative seizure frequency. Factors associated with persistent seizures (Engel Class II-IV outcome) included residual epileptogenic tissue adjacent to the resection cavity (40%), an additional epileptogenic zone distant from the resection cavity (32%), and the presence of a hemispheric epilepsy syndrome (28%). While seizure outcomes in pediatric epilepsy surgery may be improved by the use of high-resolution neuroimaging and invasive electrographic studies, a more aggressive resection should be considered in certain patients, including hemispherectomy if a hemispheric epilepsy syndrome is suspected. Family counseling regarding treatment expectations is critical, and reoperation may be warranted in select cases.

Long-term memory performance after surgical treatment of unilateral temporal lobe epilepsy (TLE)

Long-term cognitive and memory performance after surgical treatment of unilateral temporal lobe epilepsy (TLE) was investigated in a series of 98 patients. Neuropsychological evaluation was performed preoperatively and after one and three years postoperatively. Fifty-eight patients (59%) became seizure-free (Engel's class I). Verbal learning and memory declined in long-term follow-up in both left and right TLE groups. Visual memory remained stable. Ongoing postoperative seizures were related to decline in the immediate recall of logical prose, and postoperative seizure-freedom to improvement in verbal fluency in patients with left TLE. There was significant variability in the individual postoperative long-term memory performance. Left side of surgery, better baseline performance and older age at surgery were identified as risk factors for individual decline in delayed verbal memory. Selected patients undergoing surgery for drug-resistant TLE are at risk for significant postoperative memory decline especially after left temporal lobe surgery. Preoperative counseling and long-term follow-up of cognitive performance in individual patients is recommended. Additionally, more accurate predictors of individual postoperative memory performance would be needed.

Can DTI fiber tracking of the optic radiations predict visual deficit after surgery?

ObjectSparing optic radiations can be of paramount importance during epilepsy surgery of the temporal lobe. The anatomical heterogeneity of the Meyer’s loop of the optic radiations could be assessed by means of diffusion tensor tractography. We used temporal lobe surgery as a lesion model to validate this method. Material and methodsWe analyzed the distance between the temporal pole (TP) and Meyer’s loop (ML) and the correlation between visual impairment and the percentage of virtual fibers injured. MRI studies were performed in 18 patients and 13 controls. Diffusion tensor imaging (DTI) with fiber tracking was performed using four different algorithms and various gradient directions (15 or 32) and fractional anisotropy (FA) thresholds (0.18, 0.20, and 0.22). To find the best DTI model, we tested each gradient direction and FA threshold on 16 operated patients by pre- and post-operative visual field testing that analyzed the percentage of virtual fibers damaged on 3-month-post-operative MRIs. ResultsMarked individual differences were noted in the TP-ML distances (mean: 25.4mm; range 18.2–38.3mm; standard deviation: 4.7) but with no significant difference between patients and controls (p=0.9). The percentage of virtual fibers reconstructed by tracking and damaged by surgery was correlated with visual impairment. Significant differences appeared between algorithm types. The tensor-line algorithm with 15-direction resolution and an anisotropy threshold of 0.18 seemed to be the most relevant. A threshold of 5.5% of injured virtual fiber could predict a visual defect with a sensitivity of 71.4% and a specificity of 87.5%. ConclusionOptic radiation tractography by DTI could be a useful method to assess an individual patient’s risk of postoperative visual deficit.

Interictal psychosis following temporal lobe surgery: dentate gyrus pathology.

De novo interictal psychosis, albeit uncommon, can develop in patients following temporal lobe surgery for epilepsy. Pathological alterations of the dentate gyrus, including cytoarchitectural changes, immaturity and axonal reorganization that occur in epilepsy, may also underpin co-morbid psychiatric disorders. Our aim was to study candidate pathways that may be associated with the development of interictal psychosis post-operatively in patients with hippocampal sclerosis (HS). A total of 11 patients with HS who developed interictal psychosis (HS-P) post-operatively were compared with a matched surgical HS group without psychosis (HS-NP). Resected tissues were investigated for the extent of granule cell dispersion, mossy fibre sprouting and calbindin expression in the granule cells. We quantified doublecortin, mini-chromosome maintenance protein 2 (MCM2) and reelin-expressing neuronal populations in the dentate gyrus as well as the distribution of cannabinoid type 1 receptor (CBR1). The patterns of neuronal loss and gliosis were similar in both groups. HS-P patients demonstrated less mossy fibre sprouting and granule cell dispersion (p < 0.01) and more frequent reduction in calbindin expression in granule cells. There were no group differences in the densities of immature MCM2, doublecortin and reelin-positive cells. CBR1 labelling was significantly lower in Cornu ammonis area CA4 relative to other subfields (p < 0.01); although reduced staining in all hippocampal regions was noted in HS-P compared with HS-NP patients, the differences were not statistically significant. The alterations in dentate gyrus pathology found in HS-P patients could indicate underlying differences in the cellular response to seizures. These mechanisms may predispose to the development of psychosis in epilepsy and warrant further investigation.

Subjective Memory Evaluation before and after Temporal Lobe Epilepsy Surgery

Subjective memory (SM), a self-evaluation of memory, in contrast to objective memory (OM) measured by neuropsychological testing, is less well studied in patients with epilepsy. We assessed SM before and after temporal lobectomy. The Frequency of Forgetting 10 scale (FOF-10), developed to evaluate SM in dementia, was given before and one year after temporal lobectomy. Reliability and validity for use in epilepsy were first assessed. Measures of depression (CES-D) and neuroticism (PANAS) were done before and after surgery as well as complete neuropsychological assessment of OM. Correlation analysis between FOF-10 results and all the other variables was implemented. In 48 patients the FOF-10 was reliable and valid showing high internal consistency in all items (Cronbach's alpha >0.82) and high reproducibility (p<0.01). The FOF-10 also correlated with the memory assessment clinics self rating scale (MAC-S) (p<0.01). FOF-10 scores improved or were unchanged postoperatively in 28 patients (58%) and worsened in 20 (42%). The FOF-10 did not significantly correlate with memory scores from neuropsychological testing but did correlate with perceived word finding difficulty (p<0.001) and postoperative depression (p<0.05). A reduction in number of antiepileptic drugs (AEDs) after surgery distinguished those with improved postoperative SM. No correlation was found between SM and neuroticism, side of surgery or number of seizures. The FOF-10 is a brief and reliable measure of subjective memory in patients with epilepsy. Perceived memory impairment reflects more emotional state, language problems and quantity of AEDs than actual defects in memory function. These results would potentially be useful in presurgical counselling and management of memory issues after temporal lobe surgery.

Reducing versus stopping antiepileptic medications after temporal lobe surgery.

ObjectiveTo study the safety of antiepileptic drug (AED) withdrawal after temporal lobe epilepsy (TLE) surgery.MethodsWe reviewed patients who underwent TLE surgery from 1995 to 2011, collecting data on doses, dates of AED initiation, reduction, and discontinuation. Predictors of seizure outcome were defined using Cox-proportional hazard modeling and adjusted for, while comparing longitudinal seizure-freedom in patients for whom AEDs were unchanged after resection as opposed to reduced or stopped.ResultsA total of 609 patients (86% adults) were analyzed. Follow-up ranged from 0.5 to 16.7 years. Most (64%) had hippocampal sclerosis. Overall, 229 patients had remained on their same baseline AEDs, while 380 patients stopped (127 cases) or reduced (253 cases) their AEDs. Mean timing of the earliest AED change was shorter in patients with recurrent seizures (1.04 years) compared to those seizure-free at last follow-up (1.44 years; P-value 0.03). Whether AEDs were withdrawn 12 or 24 months after surgery, there was a 10–25% higher risk of breakthrough seizures within the subsequent 2 years. However, 70% of patients with seizure recurrence after AED discontinuation reachieved remission, as opposed to 50% of those whose seizures recurred while reducing AEDs (P = 0.0001). Long-term remission rates were similar in both AED discontinuation and “unchanged” groups (82% remission for AEDs withdrawn after 1 year and 90% for AEDs withdrawn after 2 years), while only 65% of patients whose recurrences started during AED reduction achieved a 2-year remission by last follow-up.InterpretationAED withdrawal increases the short-term risk of breakthrough seizures after TLE surgery, and may alter the long-term disease course in some patients.

Epilepsy Surgery Series: A Study of 502 Consecutive Patients from a Developing Country

Purpose. To review the postoperative seizure outcomes of patients that underwent surgery for epilepsy at King Faisal Specialist Hospital & Research Centre (KFSHRC). Methods. A descriptive retrospective study for 502 patients operated on for medically intractable epilepsy between 1998 and 2012. The surgical outcome was measured using the ILAE criteria. Results. The epilepsy surgery outcome for temporal lobe epilepsy surgery (ILAE classes 1, 2, and 3) at 12, 36, and 60 months is 79.6%, 74.2%, and 67%, respectively. The favorable 12- and 36-month outcomes for frontal lobe epilepsy surgery are 62% and 52%, respectively. For both parietal and occipital epilepsy lobe surgeries the 12- and 36-month outcomes are 67%. For multilobar epilepsy surgery, the 12- and 36-month outcomes are 65% and 50%, respectively. The 12- and 36-month outcomes for functional hemispherectomy epilepsy surgery are 64.2% and 63%, respectively. According to histopathology diagnosis, mesiotemporal sclerosis (MTS) and benign CNS tumors had the best favorable outcome after surgery at 1 year (77.27% and 84.3%, resp.,) and 3 years (76% and 75%, resp.,). The least favorable seizure-free outcome after 3 years occurred in cases with dual pathology (66.6%). Thirty-four epilepsy patients with normal magnetic resonance imaging (MRI) brain scans were surgically treated. The first- and third-year epilepsy surgery outcome of 17 temporal lobe surgeries were (53%) and (47%) seizure-free, respectively. The first- and third-year epilepsy surgery outcomes of 15 extratemporal epilepsy surgeries were (47%) and (33%) seizure-free. Conclusion. The best outcomes are achieved with temporal epilepsy surgery, mesial temporal sclerosis, and benign CNS tumor. The worst outcomes are from multilobar surgery, dual pathology, and normal MRI.

Surgery for intractable temporal lobe epilepsy: experience of a single institution.

In the treatment of epilepsy, encouraging results have been achieved with surgical treatment, especially for temporal lobe epilepsy (TLE). Drug resistance must be diagnosed as early as possible, because the ensuing seizures can be eliminated surgically via temporal lobe surgery in a high percentage (70%-90%) of patients. In this study we share our experience, in a single institution, of surgical treatment of intractable TLE. Between March 2006 and November 2010 we performed 127 corticoamygdalohippocampectomy (CAH) procedures. All CAH surgical procedures were done as described by Niemeyer's technique. Resection lengths were 4-4.5 cm from the temporal pole. At the end of 24 months, 79.7% (n = 94) patients were still on antiepileptic medications, with 55 of them on a decreased number or dose of drugs, and 20.3 (n = 24) patients were antiepileptic drug-free. Postoperative Engel's classes were 1, 2, and 3 in 87.2%, 5.08%, and 7.6%, respectively. There was no mortality in follow-up, and dysphasia in 1 patient (0.84%) was the only morbidity. In our series we found that the outcome of surgery is associated with careful patient selection, which requires a detailed investigation of the patients. Our final conclusion is that outcome scores are independent of age, pathology, or sex but are dependent on correct patient selection.

Cognitive function fifty-six years after surgical treatment of temporal lobe epilepsy: A case study

We report a long-term follow-up investigation of a patient who was operated in 1954 to relieve intractable temporal lobe seizures characterized by automatism and amnesia. Neuropsychological review at 16 months after surgery showed a slight residual impairment of verbal comprehension and verbal recall and good nonverbal skills. Seizure-free since the operation except for two attacks in the early postoperative years, the patient has been off medication for 25 years and has pursued a successful career as an artist.Our investigation at 56 postoperative years focused on cognitive skills, with some emphasis on learning and memory; a clinical examination was also performed, and the anatomical extent of the resection was determined on 3-Tesla magnetic resonance imaging. Four age- and IQ-appropriate women were tested as healthy control subjects. The patient showed material-specific impairments in language and verbal memory compared with the control subjects and also compared with her own earlier performance, but her performance on other cognitive tasks did not differ from that of the control subjects. Thus, her specific deficits had worsened over time, and she was also impaired compared with healthy individuals of her age, but her deficits remained confined to the verbal sphere, consistent with her temporal lobe seizure focus and surgery.

The Significance of Insular Hypometabolism in Temporal Lobe Epilepsy in Children

Background and Purpose:Temporal lobe epilepsy is one of the most common forms of medically refractory epileptic syndromes. In a small percentage, temporal lobectomy fails to control the seizures in patients with epilepsy of clear temporal origin, and in some of these patients, seizures originating from the insular cortex is believed to be the cause behind the surgical failures. We retrospectively analyzed the [18F]FDG-positron emission tomography (PET) results of patients who received temporal lobe surgery for presence of insular hypometabolism, and compared the surgical outcome to verify whether insular hypometablism was related with difference in post-operative results.Methods:13 patients were enrolled, and clinical variables, post-operative pathology, magnetic resonance imaging and PET results were analyzed for possible differences between the patients with or without insular hypometabolism.Results:7 patients showed insular hypometabolism, while 6 patients were clear of insular lesion on PET exam. 8 patients received anterior temporal lobectomy with amygdalohippocampectomy (AH), 2 patients received radical temporal lobectomy with AH, and 3 patients received insular cortisectomy. Post-operative results were favorable in 8 patients and unfavorable in 5, with unfavorable outcomes in all recipients of insular cortisectomy. Presence of insular hypometabolism did not have any significant relationship with the post-surgical outcome (p=0.266), but its trend showed a tendency towards favorable outcome if insular hypometabolism was not present.Conclusions:Presence of insular hypometabolism in [18F]FDG-PET analysis was not significantly correlated with the post-operative outcome, and recipients of insular cortisectomy among our patients with insular hypometabolism resulted in poor surgical outcome. However, the outcome trend showed a tendency towards better surgical outcome with absence of hypometabolic lesion in the ipsilateral insular cortex. Further studies employing a larger patient group is needed.