Failed surgery for temporal lobe epilepsy: predictors of long-term seizure-free course

OBJECTIVES: To identify prognostic factors which predict the outcome 2 years after TLE surgery in those patients who were not seizure-free at the 6-month postoperative examination. METHODS: We included 86 postoperative TLE patients who had undergone presurgical evaluation, including video-EEG and high-resolution MRI, and who had seizures between the second and sixth postoperative months. RESULTS: 32% of patients were seizure-free in the second postoperative year. We found that normal MRI findings and secondarily generalized seizures (SGTCS) preoperatively were associated with a non-seizure-free outcome, while rare postoperative seizures and ipsilateral temporal IED with seizure-free outcome. Newly administered levetiracetam showed a significant positive effect on the postoperative outcome independent of other prognostic factors. Five of seven patients who received levetiracetam became seizure-free (p = 0.006). CONCLUSION: One-third of patients who did not become seizure-free immediately after surgery, eventually achieved long-term seizure freedom. We suggest watching for long-term seizure freedom after failed epilepsy surgery especially in patients who had rare postoperative seizures, focal MRI abnormality, ipsilateral temporal spikes, or no SGTCS preoperatively. Levetiracetam may have a positive effect on postsurgical seizures.     

Temporal lobe epilepsy: analysis of patients with dual pathology

OBJECTIVES: To determine the frequency and types of dual pathology in patients with temporal lobe epilepsy (TLE) and to analyze the clinical manifestations and surgical outcome. MATERIAL AND METHODS: A total of 240 patients with TLE underwent temporal resections following a comprehensive pre-surgical evaluation. Thirty-seven (15.4%) of these had hippocampal sclerosis (HS) or temporal lobe gliosis in association with another lesion (dual pathology). RESULTS: Eighteen of 37 patients with dual pathology had heterotopia of the temporal lobe, nine had cortical dysplasia, four had cavernous angiomas or arteriovenous malformations, one had a dysembryoplastic neuroepithelial tumor, one had a contusion and four patients had cerebral infarctions in childhood. 68.5% had abnormal head magnetic resonance imagings, 91.3% had abnormal positron emission tomography scans, and 96% had abnormal ictal SPECT. The intracarotid amobarbital procedure (IAP) showed impaired memory of the epileptogenic side in 72% of the patients. Twenty patients had left and 17 had right-sided en bloc temporal resections, including the lesion and mesial temporal structures. Twenty-six (70.2%) became seizure-free, eight (21.6%) had rare seizures, two (5.4%) had worthwhile seizure reduction and one (2.7%) had no improvement (range of follow-up 1-16 years, mean = 7.4 years). CONCLUSIONS: 15.4% had dual pathology. The dual pathology was almost exclusively seen in patients whose lesions were congenital, or occurred early in life, suggesting that the hippocampus is more vulnerable and more readily develops HS in early childhood. Resections, including the lateral and mesial temporal structures led to a favorable outcome with no mortality and little morbidity.     

Surgical implications of neuromagnetic spike localization in temporal lobe epilepsy

PURPOSE: To investigate the clinical usefulness of magnetoencephalography (MEG) as a guide to the surgical treatment of temporal lobe epilepsy (TLE). METHODS: Preoperative spike localization by MEG was compared with seizure outcome and postoperative spike localization at 12 months after resective surgery in 16 patients with TLE. Spike localization was classified into anterior temporal (AT) and non-AT localization in 11 patients without neocortical lesion treated with anterior temporal lobectomy (ATL); and lesion and lobar localization in five patients with neocortical lesion treated with lesionectomy (n = 3) or lesionectomy with medial temporal resection (n = 2). RESULTS: All five patients with AT localization became seizure free and spike free after surgery. Among the six patients with non-AT localization, two became seizure free and spike free, two became seizure free with residual spikes, one had residual seizures but no spikes, and one had both residual seizures and spikes. All three patients with lesion localization and two with lobar localization had favorable seizure outcome and became spike free after surgery. CONCLUSIONS: MEG spike localization can identify neocortical sources remote from the presumed epileptogenic area. Favorable seizure outcome can be expected in patients with AT localization after ATL and patients with lesion localization after lesionectomy. In contrast, non-AT localization indicates either nonmedial TLE or spike propagation to the posterior and extratemporal neocortex. Similarly, lobar localization indicates spike propagation from an epileptogenic lesion or extensive epileptogenicity. Patients with non-AT localization or lobar localization should undergo intensive evaluations, such as intracranial EEG, for improved seizure outcome.     

Prognostic Significance of Ictal and Interictal Epileptiform Activity in Temporal Lobe Epilepsy

Summary: Long-term electrocorticograms (ECoG), recorded by chronically implanted subdural electrodes during preoperative evaluation of 59 patients with temporal lobe epilepsy (TLE) were analyzed retrospectively to assess the prognostic relevance of distribution of interictal epileptiform potentials (IEP) and seizure origin (SO) and to investigate factors affecting their lateralization. Subsequent to preoperative evaluation, a standardized two thirds anterotemporal lobectomy including subtotal hippocampectomy had been performed in all patients. The following results were obtained: (a) Only patients with 100% lateralization of SO and IEP had excellent seizure outcome (= 89% seizure-free); (b) patients with bitemporal SO were unlikely to benefit from surgical treatment (=12.5% seizure-free); (c) 40–56% patients with unilateral temporal SO and bitemporal IEP, became seizure-free irrespective of the degree of lateralization of IEP; and (d) multidimensional analysis of variance showed that lateralization of SO, presence of a magnetic resonance imaging (MRI)-detectable lesion, presence of hippocampal sclerosis, presence of febrile seizures and seizures at age ≥6 years are the five most important variables indicating abolition of seizures. Combined analysis of ECoG-recorded SO and IEP allows prediction of postoperative seizure control within close boundaries.     

Implications of Seizure Termination Location in Temporal Lobe Epilepsy

Summary: Where propagating symptomatic seizures terminate has not been studied, but might provide insight into mechanisms of seizure termination as well as localization of epileptogenic tissue. We investigated location of seizure termination in 50 refractory temporal lobe epilepsy (TLE) patients who had intracranial EEG recording of spontaneous seizures and subsequent temporal lobe resection with > 1–year follow-up. Only seizures that had onset in the resected temporal lobe were included. Location of the electrical termination for each seizure in each patient was categorized as diffuse, localized to the onset location, or localized elsewhere. The proportion of all seizures in each patient in each category was analyzed with respect to the outcome of surgery. Outcome was classified as seizure-free or persistent seizures. Diffuse seizure termination was noted equally frequently in both outcome groups. However, the 27 patients without seizures postoperatively had a significantly greater proportion of seizures with termination in the onset location (67%) than did the 23 patients with persistent seizures (36%, p < 0.01). The seizure-free patients also had a significantly lower proportion of seizures with localized termination elsewhere than the onset site (13%) than did patients with persistent seizures (45%, p < 0.005). Localization of the site of termination of seizures of focal origin to cortical regions other than the onset is associated with a poorer surgical prognosis. This observation raises the possibility of additional abnormal epileptogenic cortical regions with impaired seizure-terminating capabilities.     

Magnetoencephalography source localization and surgical outcome in temporal lobe epilepsy.

OBJECTIVE: We prospectively investigated the role of magnetoencephalography (MEG) in localizing the seizure focus and in predicting outcome to surgical resections for intractable temporal lobe epilepsy (TLE). METHODS: We performed simultaneous interictal EEG and MEG recording (two 37-channel system) in 26 TLE patients followed by MEG source localization. We correlated early modeling dipoles with intracranial EEG, temporal surgical resection and surgical outcome. RESULTS: There were 12 patients who had anterior temporal horizontal or tangential dipoles to the anterior infero-lateral temporal tip cortex. Two patients underwent selective amygdalo-hippocampectomy (SAH) and nine patients had antero-medial temporal lobectomy (AMTL). All patients had successful outcome except for one patient who initially failed SAH, but became seizure-free after AMTL. There were 11 patients who demonstrated anterior temporal vertical or tangential oblique dipoles. Five patients had AMTL and three had SAH; all became seizure free. Five of above 23 patients had invasive EEG and demonstrated mesial seizure onset. Three TLE patients had lateral vertical dipoles that were concordant with intracranial EEG and these became seizure free after temporal neocortical resections. CONCLUSIONS: MEG source analysis produces distinct source patterns that provide useful localizing information, predict surgical outcome, and may aid in planning limited surgical resection in TLE.     

Lateralization of temporal lobe epilepsy using resting functional magnetic resonance imaging connectivity of hippocampal networks

Purpose: Early surgical intervention can be advantageous in the treatment of refractory temporal lobe epilepsy (TLE). The success of TLE surgery relies on accurate lateralization of the seizure onset. The purpose of this study was to determine whether resting functional MRI (fMRI) connectivity mapping of the hippocampus has the potential to complement conventional presurgical evaluations in distinguishing left from right TLE. In addition, we sought to determine whether this same network might separate patients with favorable from unfavorable postoperative outcomes. Methods: Resting fMRI acquisitions were performed on 21 patients with TLE and 15 healthy controls. The patients included seven patients with left TLE and seven patients with right TLE with seizure-free postoperative outcome, and five patients with left TLE and two patients with right TLE with recurring seizures after surgery. Functional connectivity maps to each hippocampus were determined for each subject and were compared between the controls and the seizure-free patients with left TLE and with right TLE. The one network identified was then quantified in the patients with TLE and recurring seizures. Key Findings: The resting functional connectivity between the right hippocampus and the ventral lateral nucleus of the right thalamus was the most statistically significant network to distinguish between seizure-free patients with left TLE and with right TLE with high sensitivity and specificity. This connectivity was also significantly greater in the seizure-free patients with left TLE than the healthy controls. Finally, six of the seven patients in whom seizures recurred after surgery had connectivity values in this network unlike those who were seizure-free. Significance: This study identified a region in the ventral lateral nucleus of the right thalamus whose connectivity to the hippocampi separates left from right TLE subjects. This suggests that the quantification of resting-state functional magnetic resonance imaging (MRI) connectivity across this network may be a potential indicator of lateralization of TLE that may be added to other presurgical MRI assessments. Further validation in a larger, independent cohort is required.     

Ictal vocalizations occur more often in temporal lobe epilepsy with dominant (left-sided) epileptogenic zone

Objective:   To investigate the lateralization value of ictal vocalizations in temporal lobe epilepsy (TLE).
Methods:   We reviewed video-recordings of 97 patients who had undergone presurgical evaluation programs with video-EEG (electroencephalography)–recorded complex partial seizures (CPS) and high-resolution magnetic resonance imaging (MRI). All patients had surgery due to TLE and became seizure-free. In 57 patients, determination of speech dominance was necessary by using Wada tests or functional MRI (fMRI). To reevaluate the archived seizures, we reviewed one to three consecutively recorded CPS of each patient. Altogether 223 archived seizures were analyzed. Ictal vocalization was considered to be present in a particular patient if it occurred in at least one of the recorded seizures.
Results:   Ictal vocalizations occurred in 22 patients. They occurred in 37% of left-sided and in 11% of right-sided patients with TLE (p = 0.003). In patients with determined speech lateralization, ictal vocalizations occurred in 37% of the dominant and in 14% in patients with nondominant epileptogenic zone (p = 0.04). In patients with ictal vocalizations, epilepsy began at age 8.7 ± 6, whereas in the remaining patients, epilepsy started at age 14.0 ± 9 (p = 0.017). Logistic regression showed that both hemispheric dominance and age at onset were independently associated with pure ictal vocalization (PIV).
Conclusions:   Ictal vocalization is a frequent phenomenon, occurring in 23% of patients with TLE. It is more often associated with left-sided and early onset TLE. Our results may improve the lateralization of the epileptogenic zone and suggest that nonspeech vocalizations in humans are related to the dominant (left-sided) hemisphere. Our study is a further argument that there are different subtypes of TLE depending on the age at onset.     

Temporal lobe epilepsy surgery: outcome, complications, and late mortality rate in 215 patients

PURPOSE: We studied the surgical outcome, complications, and the late mortality rate in a large group of patients with medically refractory temporal lobe epilepsy (TLE). METHODS: Two-hundred fifteen patients with TLE were treated surgically between 1984 and 1999 after a comprehensive presurgical evaluation. Patients were followed up at 6 weeks, 3-6 months, and yearly thereafter. In addition, questionnaires were sent on the anniversary of their surgery. Surgical outcome (Engel's classification), complication rate, and factors contributing to late mortality were analyzed. Standardized mortality ratios (SMRs) were calculated. RESULTS: There was no surgical mortality. Two (0.9%) had mild hemiparesis, one (0.4%) had a hemianopia, seven (3.2%) had transient cranial nerve palsies, and eight (3.7%) had transient postoperative language difficulties. One hundred forty-eight (69%) became seizure free, 43 (20%) had rare seizures, 14 (6.5%) had worthwhile seizure reduction, and 10 (4.6%) had no improvement (follow-up, 1-15 years). Three (2%) of 148 seizure-free patients died during follow-up, compared with eight (11.9%) of 67 not seizure-free patients. The mean duration of epilepsy before surgery for the surviving patients was 17.8 years, and for those patients who died, 25.9 years (p < 0.05). Six (5.7%) of 104 patients with right-sided resections died during follow-up, compared with five (4.5%) of 111 with left-sided resections. CONCLUSIONS: Eighty-nine percent of patients became seizure free or had rare seizures, with low morbidity, and no surgical mortality. The late mortality occurred predominantly in patients with persistent seizures (SMR, 7.4). Those patients who died had a longer duration of epilepsy before surgery. In contrast, among those patients who became seizure free, the mortality rate was much lower, and similar to the general population of Indiana (SMR, 1.7).     

Prognostic Value of Qualitative Magnetic Resonance Imaging Hippocampal Abnormalities in Patients Undergoing Temporal Lobectomy for Medically Refractory Seizures

Summary: In patients with temporal lobe epilepsy (TLE), high-resolution, magnetic resonance imaging (MRI) frequently demonstrates hippocampal atrophy and increased hippocampal signal. To assess the prognostic value of these findings, we studied 51 patients evaluated prospectively by a radiologist blinded to other preoperative evaluations. Thirty-one of 51 (61%) patients undergoing temporal lobectomy had visually apparent hippocampal atrophy o r increased hippocampal signal on MRI (25 ipsilateral 3 contralateral, and bilateral to the operated site). Patients with ipsilateral abnormalities became seizure-free more frequently than patients with normal scans [24 of 25 (96%) vs. 10 of 20 (50%) p < 0.015]. Both ipsilateral hippocampal atrophy and ipsilateral increased hippocampal signal independently predicted a seizure-free outcome. Qualitative MRI provides important prognostic information in patients undergoing temporal lobectomy.     

Ictal spitting in left temporal lobe epilepsy: report of three cases.

PURPOSE: Ictal spitting is rarely reported in patients with epilepsy. More often it is observed in patients with temporal lobe epilepsy (TLE) and is presumed to be a lateralizing sign to language nondominant hemisphere. We report three patients with left TLE who had ictal spitting registered during prolonged video-EEG monitoring. METHODS: Medical charts of all patients with medically refractory partial epilepsy submitted to prolonged video-EEG monitoring in the Epilepsy Unit at UNIFESP during a 3-year period were reviewed, in search of reports of ictal spitting. The clinical, neurophysiological and neuroimaging data of the identified patients were reviewed. RESULTS: Among 136 patients evaluated with prolonged video-EEG monitoring, three (2.2%) presented spitting automatisms during complex partial seizures. All of them were right-handed, and had clear signs of left hippocampal sclerosis on MRI. In two patients, in all seizures in which ictal spitting was observed, EEG seizure onset was seen in the left temporal lobe. In the third patient, ictal onset with scalp electrodes was observed in the right temporal lobe, but semi-invasive monitoring with foramen ovale electrodes revealed ictal onset in the left temporal lobe, confirming false lateralization in surface records. The three patients became seizure-free following left anterior temporal lobectomy. CONCLUSIONS: Ictal spitting is a rare finding in patients with epilepsy, and may be considered a localizing sign of seizure onset in the temporal lobe. It may be observed in seizures originating from the left temporal lobe, and thus should not be considered a lateralizing sign of nondominant TLE.     

Electro-clinical characteristics and postoperative outcome of medically refractory tumoral temporal lobe epilepsy

BACKGROUND: Very few studies have specifically addressed surgical treatment and outcome of patients with tumor-related temporal lobe epilepsy (TLE). AIM: To define the postoperative seizure outcome and the factors that influenced the outcome of patients with tumor-related TLE. MATERIALS AND METHODS: We selected patients whose surgical pathology revealed a temporal lobe neoplasm and who had completed > 1 year of postoperative follow-up. We reviewed the clinical, EEG, radiological and pathological data, and the seizure outcome of these patients and assessed the factors that influenced the outcome. RESULTS: Out of the 409 patients who underwent surgery for refractory TLE during the 8-year study period, there were 34 (8.3%) patients with temporal lobe neoplasms. The median age at surgery was 20 years and the median duration of epilepsy prior to surgery was 9.0 years. MRI revealed tumor in the mesial location in 21 (61.8%) patients. Interictal and ictal epileptiform EEG abnormalities were localized to the side of th 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, 27 (79%) patients were completely seizure-free. The only factor that predicted long-term seizure-free outcome was being seizure-free during the first two postoperative years. CONCLUSIONS: Our results emphasize the fact that in patients with tumoral TLE, when the seizures are medically refractory, surgery offers potential for cure of epilepsy in the majority.     

Secondary white matter degeneration of the corpus callosum in patients with intractable temporal lobe epilepsy: a diffusion tensor imaging study

Imaging changes in patients with focal epilepsy are not only seen in areas where seizures arise but often also in remote locations. The mechanism for such changes is unknown. We aimed to investigate whether patients with temporal lobe epilepsy (TLE) have microstructural changes involving the posterior portion of the corpus callosum (CC), where it links the temporal lobes, using presurgical diffusion tensor imaging (DTI) sequences. Ten patients with medically intractable TLE (two mesial TLE, eight neocortical TLE) who had seizure-free surgical outcomes were compared with 10 healthy controls. The regions of interest were outlined at each Witelson region (WR). Fractional anisotropy (FA), apparent diffusion coefficient (ADC) and three principal diffusivity values (lambda1, lambda2, lambda3) were determined in each WR. We performed tractography originating at each WR. In the TLE patients, the FA values were lower at the splenium of the corpus callosum (WR 7) compared to controls (p<0.05). Analysis of Eigen values in that location revealed that lambda1 values were decreased while lambda2 and lambda3 values were increased (p<0.05). Tractography revealed the connection between both temporal lobes via WR 7. In conclusion, decreased FA values with decreased lambda1 and increased lambda2 and lambda3 at the splenium of CC suggest that the pathologic changes, Wallerian degeneration, extend to the corpus callosum in TLE patients. Seizure-induced damage may cause secondary white matter degeneration along the tapetum and through the splenium of the corpus callosum, a potential pathway of spread in temporal lobe seizures.     

Proton magnetic resonance spectroscopic imaging studies in patients with newly diagnosed partial epilepsy

PURPOSE: To assess whether the N-acetyl aspartate (NAA) to creatine ratio (NAA/Cr) is abnormally low at the onset of epilepsy and whether successful treatment of seizures with antiepileptic drugs is sufficient for normalization of NAA/Cr. PATIENTS AND METHODS: Proton magnetic resonance spectroscopic imaging (1H-MRSI) was used to measure NAA/Cr in temporal lobes of eight patients with newly diagnosed epilepsy before or soon after starting medication. Six patients had follow-up 1H-MRSI examinations 7 months later. Clinical pattern of the seizures and the EEG findings suggested partial seizures in all and TLE in five patients. None of the patients had lesional epilepsy according to magnetic resonance imaging. RESULTS: Initial 1H-MRSI of the temporal lobes showed significantly low NAA/Cr values in five of eight patients. Five of six patients who had follow-up 1H-MRSI were seizure-free after using medication; the remaining patient did not take medication and continued to experience occasional auras. Wilcoxon rank sign comparison of NAA/Cr on initial 1H-MRSI examination and follow-up 1H-MRSIs showed no significant difference (Z = 135, p = 0.893, 2-tailed) for five seizure-free patients. CONCLUSIONS: Neuronal dysfunction is present at an early stage of the epileptic process. NAA/Cr recovery in seizure-free patients controlled with antiepileptic drugs is less evident, compared with successful surgical treatment. Thus, absence of seizures is not necessarily coupled with NAA/Cr improvement and observed variable response warrants further investigation.     

Hypersalivation in temporal lobe epilepsy

PURPOSE: We sought to determine whether hypersalivation helps lateralize seizure onset during complex partial seizures of temporal lobe origin. Several clinical signs, which help lateralize seizure onset, have been reported in temporal lobe epilepsy (TLE). Increased salivation only occasionally has been reported as a manifestation of partial epilepsy. METHODS: Of 590 consecutive patients admitted for video-EEG monitoring, either as a part of a presurgical evaluation of medically intractable epilepsy or for diagnosis and clarification of their paroxysmal symptoms, we identified 10 patients with ictal hypersalivation as a prominent manifestation of complex partial seizures. We reviewed the clinical features, scalp-sphenoidal video-EEG monitoring, intracarotid amytal (Wada) testing, hippocampal volumetric magnetic resonance imaging (MRI), and fluorodeoxyglucose-positron emission tomography (FDG-PET) scans of these patients. RESULTS: Of the 10 patients with ictal hypersalivation, seven patients had nondominant/right TLE, and three patients had dominant/left TLE. All patients had hippocampal atrophy on volumetric MRI. Eight of the 10 patients underwent standard temporal lobectomy with amygdalohippocampectomy (six right, two left). All of the operated-on patients had a seizure-free (Engel class I) outcome, and their increased salivation resolved. Two patients, who did not undergo surgical treatment, continue to have complex partial seizures with increased salivation. CONCLUSIONS: We conclude that increased salivation as a prominent ictal finding in complex partial seizures of temporal lobe origin is more likely to be of nondominant temporal lobe origin. Further studies with larger numbers of patients are needed to replicate this finding.     

Semiology of Temporal Lobe Seizures: Value in Lateralizing the Seizure Focus

Summary: Purpose: To determine the lateralizing value of the clinical manifestations of seizures in patients with temporal lobe epilepsy (TLE), we made a retrospective videotape analysis of complex partial seizures (CPS) in 55 patients who underwent temporal lobectomy and were seizure-free postopera-tively for >2 years. Methods: Blinded to clinical details, we reviewed videotapes from video-EEG telemetry monitoring with attention paid to seizure semiology. Results: Useful lateralizing features included unilateral clonic activity (with the seizure focus contralateral in all patients), unilateral dystonic or tonic posturing (with the seizure focus contralateral in 90 and 86%, respectively), unilateral automatisms (with the seizure focus ipsilateral in 80%), and ictal speech preservation (with the seizure focus contralateral to the language-dominant hemisphere in 80%). Versive head rotation occurring ≤10 s before seizures secondarily generalized consistently predicted a contralateral focus. Seizure manifestations less predictive but suggestive of lateralization included ictal speech arrest and postictal speech status, with predictive values of 67%. Seizure manifestations not providing reliable lateralizing information included eye deviation, type of aura, and versive head movements occurring at times other than immediately before seizures secondarily generalized. Conclusions: In TLE, several clinical seizure manifestations are useful in lateralizing the seizure focus, although some provide no reliable information. Therefore, ictal semiology can assist in the evaluation of patients for seizure surgery, providing additional information in the lateralization of TLE.     

Long-term seizure outcome and antiepileptic drug treatment in surgically treated temporal lobe epilepsy patients: a controlled study

PURPOSE: To evaluate the long-term impact of surgical treatment on seizure outcome and antiepileptic drug (AED) use in patients with pharmacoresistant temporal lobe epilepsy (TLE). METHODS: Comparison of seizure outcome and AED us in operated-on TLE patients (n=148) and nonsurgically treated TLE patients (n=94) at a baseline visit and a follow-up visit after a mean period of 4.8 years. RESULTS: At follow-up, 44.6% of the surgical patients and 4.3% of the nonsurgical patients had been continuously seizure- free since the baseline visit (including the immediate postoperative period). A further 17.6% of the operated-on and 3.2% of the not operated-on patients had been seizure-free for at least the previous year; 37.8% of the surgical and 92.5% of the nonsurgical patients had had seizures during the previous 12 months (p < 0.001). Of the surgical patients, 8.8% versus none of the nonsurgical patients were AED free at follow-up; 55.4% versus 20.2% were receiving monotherapy, and 35.8% versus 79.8% were receiving polytherapy (p < 0.001). Mean number of AEDs and mean change in number of AEDs were significantly more favorable in operated-on than in non-operated-on patients. Further subgroup analysis revealed that not only the continuously seizure-free surgical patients, but also the operated-on patients with ongoing seizures took fewer AEDs than their respective non-operated-on counterparts. CONCLUSIONS: This controlled study for the first time provides comprehensive information on long-term seizure outcome and AED use in surgical TLE patients. It shows a more favorable seizure outcome and AED use in the surgically treated patients. The latter holds true even for the not seizure-free patient subgroup.     

Outcome after temporal lobectomy in bilateral temporal lobe epilepsy

We determined how noninvasive presurgical data relate to prognosis after temporal lobectomy in patients with independent bilateral temporal lobe (IBTL) complex partial seizures on the intracranial electroencephalogram (EEG). Between 1986 and 1994, 28 patients had IBTL seizures on intracranial EEG. Fifteen of these 28 patients underwent temporal lobectomy and 13 were not offered surgery. Of the 15 patients who had surgery, 10 patients became seizure-free. Magnetic resonance imaging (MRI) and the Wada test were the only variables associated with a seizure-free outcome. Seven of 10 seizure-free patients had a lateralized Wada result or the presence of unilateral hippocampal sclerosis, whereas none of the patients with persistent seizures had either of these findings. Variables not found to be predictive of a seizure-free outcome included location of scalp interictal spikes, degree of seizure-onset laterality, presence of early epilepsy risk factor, duration of epilepsy, and full-scale intelligence quotient. We conclude that MRI and the Wada test provide information of prognostic value in patients with bilateral temporal seizures independent of intracranial EEG data.     

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.     

Cases of temporal lobe epilepsy following mild encephalitis/meningitis or suspicion of these diseases

There are unexpectedly many patients with temporal lobe epilepsy (TLE) who previously experienced episodes of coma, high fever, and convulsion in childhood but were not diagnosed with encephalitis/meningitis. As these cases generally do not show obvious neurologic residua and mental retardation, the subsequent appearance of TLE is usually not ascribed to the episodes. Among 74 patients who underwent temporal lobectomy in Tokyo Metropolitan Neurological Hospital, we investigated the clinical findings, pathology, and imaging in 20 patients who had experienced childhood episodes of this type with or without diagnosis of encephalitis/meningitis. Seven patients were diagnosed with encephalitis, 10 were not diagnosed with encephalitis/meningitis, and three patients experienced seizures after vaccination. The incidence of anamnesis (27%) was higher than the previously reported incidence of central nervous system (CNS) infections (2.7%∼6.7%). A mild encephalitis/meningitis might comprise a more likely cause of TLE. Mild hemipareses appeared in eight patients after the episode, and subsequently disappeared in three of the eight patients. These episodes appeared before the age of 3 years in 75% of the cases. As the incidence of meningeal inflammatory findings on pathology (20%) was unexpectedly low, it can be presumed either that inflammatory findings disappear for a long clinical course or that there were no focal regions in the resected tissues. Hemispheral atrophy on magnetic resonance imaging (MRI) was found in 59% of the cases. Mild CNS infections are considered to be more important in the development of TLE and should be investigated in the future.