Surgical treatment of extratemporal epilepsy: clinical, radiologic, and histopathologic findings in 60 patients

PURPOSE AND METHODS: The aim of this study was to analyze clinical, radiologic, and histopathologic findings in 60 consecutive patients with medically intractable extratemporal epilepsy who were operated on between November 1987 and May 1993. RESULTS: Histologically, there were distinct structural abnormalities in 50 (83%) of the surgical specimens. Signal abnormalities on magnetic resonance imaging (MRI) were present in all patients with neoplastic lesions (n = 17) and in 94% of patients with nonneoplastic focal lesions (n = 32). Overall, structural abnormalities were detected by MRI in 47 (96%) of 49 patients with focal lesions. During a mean follow-up of 4 years, 30 (54%) patients remained completely seizure free, 11 (20%) had < or = 2 seizures per year, seven (12%) showed a seizure reduction of > or = 75%, and eight (14%) had < 75% reduction in seizure frequency. The fraction of seizure-free patients was 12 (80%) of 15 in patients with neoplastic lesions, 16 (52%) of 31 in patients with nonneoplastic focal lesions, and two (20%) of 10 for those without histopathologic abnormalities. The differences in seizure outcome between patients with and without focal lesions were statistically significant (p < 0.05), if seizure-free outcome was compared with persistent seizures. CONCLUSIONS: Focal lesions and particularly neoplasms are associated with improved postoperative seizure control compared with patients without histopathologic abnormalities. We advise caution in considering surgery to treat extratemporal epilepsy in patients who have normal MRI scans, because the outcome with the approach described in this study is poor in such cases.     

Long-term follow-up after temporal lobe resection for lesions associated with chronic seizures

A follow-up study was conducted on 60 patients who had standard en bloc anterior temporal lobe resection, including mesiotemporal structures, as treatment for temporal lobe lesions associated with chronic, medically intractable seizures. Lesions were identified as glial tumors, hamartomas, or vascular malformations. Long-term outcome was assessed in terms of seizure frequency and certain psychosocial sequelae. Seizure onset occurred at an average age of 15 years (median = 13.5 years), and patients experienced seizures for an average of 13 years prior to surgery. The mean time of follow-up was 8.4 years postsurgery (median = 6 years). The Kaplan-Meier curve at median follow-up showed a seizure-free rate of 80%. Late seizure recurrence was documented for three patients; two had been seizure-free for 10 years and one for 15 years after surgery, before re-onset of seizures in the absence of tumor recurrence. A prolonged history of seizures prior to surgery was associated with a poorer seizure outcome (p = 0.06), suggesting that secondary epileptogenesis at sites distant to the lesion may develop with years of uncontrolled seizures. There was a low tumor recurrence rate of 3.3% (two cases). The psychosocial outcome was generally good, with 67% working or engaged in educational studies, and improvement noted in 59% of cases for one or more of the psychosocial factors investigated. This study confirms that anterior temporal lobe resection for temporal lesions associated with chronic seizures is a successful treatment with a high seizure-free rate following surgery and good psychosocial outcome.     

Fluorometric assessments of acrosomal integrity and viability in cryopreserved bovine spermatozoa

It is widely agreed that after two or more seizures patients should be given antiepileptic treatment, but there is still controversy about the treatment of patients after a first unprovoked seizure. In a multicenter, randomized, open trial, patients with a first tonic-clonic seizure were randomized to immediate treatment (carbamazepine, phenytoin, phenobarbital, or sodium valproate) or to treatment only after another seizure. Fifty-two (24%) of the 215 patients randomized to immediate treatment and 85 (42%) of the 204 randomized to delayed treatment experienced seizure recurrence during follow-up. Age, acute treatment of the seizure with benzodiazepines, remote etiologic factors, and EEG abnormalities were significant predictors of relapse. Of the immediately treated patients, 87% had no seizures for a year and 68% had no seizures for 2 years, whereas only slightly fewer initially untreated patients (83% and 60%) achieved these endpoints. Patients treated after the first seizure and those treated after seizure relapse had the same time-dependent probability of achieving 1 and 2 seizure-free years. None of the variables that were prognostic predictors of relapse was significantly associated with the probability of having 1 or 2 years of seizure control. Anticonvulsants in patients presenting a first tonic-clonic seizure reduce the risk of relapse; however, 50% of patients who are not treated will never experience a second seizure. Moreover, the probability of long-term remission is not influenced by treatment of the first seizure.     

EEG findings in frontal lobe epilepsies

As a group, epilepsies of frontal lobe origin are thought to be poorly localized using surface EEG recordings. This finding may depend on the specific areas of frontal lobe from which the seizures originate or the pathologic substrate. We reviewed the presurgical surface EEGs of patients with frontal lobe epilepsy who underwent epilepsy surgery. The specific area of the frontal lobe where seizures originated was determined by 1) intracranial ictal EEG recordings, or 2) the presence of a structural lesion, identified by imaging studies in patients who achieved complete seizure control following surgery. We differentiated patients whose seizures began in the dorsolateral frontal convexity from those whose seizures began in the medial frontal region, and we correlated EEG findings in the interictal, postictal, and ictal states with seizure semiology, pathologic substrate, and surgical outcome. Four of nine patients had seizures originating in the dorsolateral frontal convexity and five had medial frontal onset seizures. Patients whose seizures originated from the dorsolateral convexity had focal interictal epileptiform abnormalities that localized to the region of seizure onset. Patients whose seizures began in the medial frontal region had either no interictal epileptiform abnormality or had multifocal epileptiform discharges. Patients whose seizures began in the dorsolateral convexity showed focal electrographic seizure activity that was localizing. This rhythmic fast activity did not appear to be substrate-specific. Patients whose seizure onset localized to the medial frontal region did not show focal electrographic seizure at clinical onset. We conclude that the scalp EEG recordings of frontal lobe epilepsies contain features that enable differentiation of seizures originating from two different regions of the frontal lobe.     

Multilobar polymicrogyria, intractable drop attack seizures, and sleep-related electrical status epilepticus

BACKGROUND AND OBJECTIVE: Patients with cortical malformations often have intractable seizures and are candidates for epilepsy surgery. Within an unselected series of patients with various forms of cortical malformation, nine patients with multilobar polymicrogyria had electrical status epilepticus during sleep (ESES) accompanied by infrequent focal motor seizures. Eight patients also had intractable atonic drop attack seizures. Because ESES usually is accompanied by a good long-term seizure prognosis, the objective of this study was to examine ESES outcome among patients with a structural lesion that is usually highly epileptogenic and has a low seizure remission trend. METHODS: The nine patients had follow-up periods lasting 4 to 19 years. All underwent brain MRI, serial sleep EEG recordings, and cognitive testing during and after ESES. RESULTS: ESES and drop attack seizures appeared between the ages of 2 and 5 years (mean, 4 years) and ceased between the ages of 5 and 12 years (mean, 8 years). At the last visit patients were 8 to 23 years of age (mean, 14.5 years) and were either seizure free or had very infrequent focal motor seizures during sleep. Three patients were free from antiepileptic drugs. In no patient was definite cognitive deterioration apparent after ESES in comparison with earlier evaluations. CONCLUSIONS: Age-related secondary bilateral synchrony underlying ESES may be facilitated in multilobar polymicrogyria. The good seizure outcome contrasts with that usually found in the presence of cortical malformations. For children with polymicrogyria and drop attack seizures, surgical treatment of the epilepsy should be considered cautiously, and sleep EEG recordings should be performed systematically.     

Surgical treatment of epilepsy due to cortical dysplasia: clinical and EEG findings

Seventeen patients with cortical dysplasia who had surgical resection for medically intractable partial epilepsy were studied. Compared with two groups of surgically treated patients with intractable epilepsy due to tumour (n = 20) and mesial temporal sclerosis (n = 40), patients with cortical dysplasia showed significantly more frequent extratemporal lesions, more frequent non-epileptiform EEG abnormalities and less favourable surgical outcome for seizure control. Patients with cortical dysplasia were younger at onset of seizures and had a lower detection rate of CT abnormalities compared with the tumour group, and lower IQ compared with the mesial temporal sclerosis group. MRI was abnormal in five of seven patients. Six patients became seizure-free or almost seizure-free but eight did not experience relief of seizures. Surgical outcome related to the extent of pathology but not to the histological abnormality. Lesions outside the temporal and frontal lobes were correlated with poor surgical outcome, as were generalised interictal EEG abnormalities, which may reflect extensive or multiple lesions. Ictal intracranial recordings were not useful for presurgical evaluation of cortical dysplasia.     

Corpus callosotomy for medically intractable seizures

To identify factors influencing outcome and morbidity in patients selected for corpus callosotomy, we retrospectively reviewed 23 patients with intractable generalized seizures who underwent corpus callosotomy between 1991 and 1994. Three patients had a complete corpus callosotomy, while 20 had an anterior callosotomy. Three of those patients subsequently had completion of the anterior callosotomy. Overall, 41% of patients were nearly or completely free of the seizure types targeted for surgical treatment, while another 45% had seizures less than half as frequently. Four patients developed simple partial motor seizures after callosotomy. A transient disconnection syndrome was observed in 57% of patients. The best predictor of good outcome was a normal preoperative MRI. Mentally retarded patients had poorer outcomes. Outcome was not predicted by extent of callosal section or lateralization on neurological examination, EEG, MRI, and SPECT. Completion of anterior callosotomy resulted in significant reductions in seizure frequency. Though most patients do not become seizure-free after corpus callosotomy, worthwhile palliation of an otherwise intractable illness can be achieved. An analysis of prognostic factors should lead to better selection of patients for surgery.     

Epilepsy surgery in the first three years of life

PURPOSE: Partial seizures in early postnatal life may be catastrophic and associated with poor long-term outcome. Epilepsy surgery can alleviate partial seizures in older children and adults, but there is little experience with surgical therapy in infancy apart from hemispheric epilepsy syndromes. METHODS: We analyzed the results of cortical resection to treat medically refractory partial epilepsy in 31 children (16 boys, 15 girls) aged <3 years (mean, 18.3 months). Subjects were included only if seizure relief was the primary indication for surgery. RESULTS: Follow-up of at least 1 year (mean, 4.6 years) in 26 patients revealed that 16 were seizure-free, 4 had >90% seizure reduction, and 6 had <90% reduction. There was no significant difference in seizure outcome between hemispherectomy/multilobar resections and lobar resections or temporal versus extratemporal resection. Seizure outcome was independent of the amount of cortex removed in nonlesional patients. Only the presence of a discrete lesion on preoperative neuroimaging correlated with a favorable outcome. Family perceptions of accelerated development in seizure-free patients were not confirmed on developmental assessment. CONCLUSIONS: We conclude that cortical resection often benefits very young children with catastrophic partial seizures, but does not guarantee enhanced neurological development. The location and extent of the excised cortex may not be critical as long as the entire epileptogenic region and lesion are removed.     

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.     

Effects of intracerebroventricular injection of histamine on memory deficits induced by hippocampal lesions in rats

This review was conducted to evaluate the long-term prognosis of children responding to vigabatrin by examining the incidence of increased seizure frequency, loss of efficacy, and appearance of new seizures in a cohort of 196 children (mean age, 68.2 months; range, 2 months to 19 years) with drug-resistant epilepsy, who had received vigabatrin as add-on treatment in clinical trials. The results indicate that an increase in seizure frequency was uncommon, occurring in only 10% of children with highly drug-resistant epilepsy and that it usually appears shortly after the initiation of treatment. It was clearly not dose-dependent and most often occurred in patients with nonprogressive myoclonic epilepsy. No specific seizure type was specially involved and usually the problem reversed on discontinuing vigabatrin. Loss of efficacy was also uncommon (12% of patients), and again no specific seizure type was found to be associated. Epilepsy syndrome does seem to be a better predictor of loss of efficacy because it occurred most often in symptomatic generalized epilepsies and cryptogenic infantile spasms. A total of 21 patients (11%) developed genuinely new types of seizures. Fifteen of these patients developed new partial seizures that had little impact on the patients' overall clinical improvement. The new partial seizures were better tolerated than the initial seizure type which in most cases had disappeared. Approximately 3% of patients experienced new generalized seizures that aggravated their initial condition. These occurred most often in patients with nonprogressive myoclonic epilepsy; therefore vigabatrin should be used with particular caution in such patients.     

Comparative efficacy of terfenadine, loratadine, and astemizole in perennial allergic rhinitis

BACKGROUND: It is not known how many children with epilepsy may not need treatment with antiepileptic drugs (AEDs), how many respond unsatisfactorily to subsequent treatment regimens, and how many achieve "acceptable control" despite lack of remission. METHODS: In a prospective multicenter hospital-based study, 494 children with a broad range of seizure types and types of epilepsy were followed up for at least 2 years. There was no standard treatment protocol. We describe the treatment strategies applied to these children by the neurologists in charge and outcome with respect to remission from seizures. RESULTS: Treatment was initially withheld in 29% of the children, and after 2 years 17% still had not received any AEDs. There were no serious complications caused by withholding treatment. Of the children treated with AEDs, 60% were still using the first AED after 2 years; 80% received monotherapy and 20%, polytherapy. Children with severe symptomatic epilepsies, such as the West or Lennox-Gastaut syndrome, received polytherapy early on in the course of treatment. When 3 regimens had failed, the chance of achieving a remission of more than 1 year with subsequent regimens was 10%. Nevertheless, 15 of 50 children receiving AEDs in whom the "longest remission ever" was less than 6 months did achieve acceptable seizure control according to the neurologist in charge of treatment. Hence, of 494 children, only 35 (7%) developed an intractable form of epilepsy, defined as failure to bring seizures under acceptable control. CONCLUSIONS: A substantial percentage of children with new-onset epilepsy did not need treatment with AEDs. Chances of achieving a good outcome declined with subsequent treatment regimens. Not all children with recurrent seizures were suffering from intractable epilepsy; some had achieved acceptable control of seizures.     

Efficacy of topiramate

In controlled clinical trials, topiramate (Topamax) has demonstrated efficacy in refractory patients with complex partial seizures and secondarily generalized tonic-clonic seizures. Approximately 45 percent of 534 patients had a > or = 50 percent reduction in seizure frequency. Limited open label trials have shown that topiramate has broad spectrum activity and may be effective in patients with primary generalized epilepsies. The efficacy of topiramate compares very favourably with the efficacy of other new antiepileptic drugs recently introduced.     

The choleretic effects of licorice: identification and determination of the pharmacologically active components of Glycyrrhiza glabra

The authors retrospectively reviewed ten pediatric brain tumor patients with intractable seizures who underwent lesionectomy without intentional identification and resection of the epileptogenic region to assess the clinical features and seizure outcome after lesionectomy in such patients. Seizures were complex partial in seven cases and simple partial, absence, and generalized tonic-clonic in one case each. Tumors were located at the medial temporal lobe in four cases, at the frontal lobe in four cases, at the parietooccipital and the suprasellar areas in one case each. The most common pathology was benign oligodendroglioma (five cases) followed by ganglioglioma (two cases). Others were pleomorphic xanthoastrocytoma, hamartoma, and primitive neuroectodermal tumor (one case each). In four cases, complete removal of the tumor was feasible. Postoperatively nine of the ten patients showed favorable seizure control (Engel's classification 1 and 2) and of these, six were seizure-free during the follow-up period (mean duration: 40 months). Therefore, lesionectomy can be an appropriate initial treatment for patients with brain tumor and medically intractable seizures.     

Vigabatrin and lamotrigin: experiences with 2 new anticonvulsants in the Swiss epilepsy clinic

Vigabatrin and lamotrigine are two new antiepileptic drugs which have recently become available. Vigabatrin is a specific and irreversible inhibitor of the enzyme gamma-amino-butyric-acid (GABA) transferase. Its administration leads to a long lasting increase in GABA, the most important inhibitory neurotransmitter. Vigabatrin is effective in both adults and children in the treatment of partial and especially complex-partial seizures. After add-on in vigabatrin to their therapeutic drug regime in 116 of our own patients, 39% of previously therapy resistant patients reported a reduced seizure frequency of at least 50% and 6% of them became seizure free. In secondarily generalized epilepsies the best results were observed in axial (infantile) spasms. In addition there was some improvement in tonic and convulsive seizures. Single patients showed increased myoclonic and clonic seizures. Initial efficacy was not always maintained during follow-up. In the experience of other authors, vigabatrin is also effective in the treatment of infantile spasms. It is not suitable for the treatment of generalized epilepsies with absences and myoclonic seizures. Most patients tolerate vigabatrin very well, although psychotic episodes are sometimes reported. So far there have been no relevant hepatic or hematological side effects. Lamotrigine is also effective in the treatment of partial seizures, for which it is approved. However, uncontrolled studies and our own experience have shown that it is even more effective in generalized seizures. As add-on therapy in absences and tonic or tonic-clonic seizures, a significant reduction in seizure frequency--in individual cases seizure freedom--can be achieved.(ABSTRACT TRUNCATED AT 250 WORDS)     

Anti-viral effect of interferon-alpha on bovine viral diarrhea virus

PURPOSE: Lamotrigine (LTG) is recognised as effective add-on therapy for focal epilepsies, but this is the first double-blind, placebo-controlled, crossover study in treatment-resistant generalised epilepsy. METHODS: The study consisted of 2 x 8-week treatment periods followed by a 4-week washout period. Patients received doses of either 75 or 150 mg daily, depending on their concomitant antiepileptic drugs (AEDs). Long-term continuation was offered at the end of the study with open-label LTG. RESULTS: Five centres in Australia recruited 26 patients who were having absence, myoclonic, or generalized tonic-clonic seizures or a combination of these. Twenty-two patients completed the study. There was a significant reduction in frequency of both tonic-clonic and absence seizure types with LTG. A 350% decrease in seizures was observed for tonic-clonic seizures in 50% of cases and for absence seizures in 33% of evaluable cases. Rash was the only adverse effect causing discontinuation. Twenty-three of 26 opted for open-label LTG, with 20 still receiving LTG for a mean of 26 months. In these 20, 80% had > or =50% seizure reduction and five (25%) were seizure free. CONCLUSIONS: This study shows that LTG is effective add-on therapy in patients with refractory generalised epilepsies. Statistically significant reduction in seizures in both absence and tonic-clonic seizure types was seen even with low doses of LTG.     

Phenobarbital in comparison with carbon tetrachloride and phenobarbital-induced cirrhosis in rat liver regeneration

PURPOSE: Status epilepticus (SE) is a major medical and a neurologic emergency associated with significant morbidity and mortality. The current definition of SE is continuous seizure activity or intermittent seizure activity without regaining consciousness, lasting > or =30 min. Epilepsy monitoring unit data indicate that many seizures self-terminate within minutes. Thus consideration was recently given to include seizure episodes lasting > or =10 min in the definition of SE. Because no large studies have been conducted on seizures lasting 10-29 min, this study was initiated to compare cases of SE and 10 to 29-min seizure episodes seen within the same period. METHODS: Patients seen at the Medical College of Virginia Hospitals of Virginia Commonwealth University over the same 2-year period were studied. Two hundred twenty-six prospective SE cases (91 children and 135 adults) and 81 retrospective 10- to 29-min seizure episodes (31 children and 50 adults) were compared. A standardized data-entry-form system was compiled on each patient and was used to evaluate the data collected. RESULTS: The 10- to 29-min seizure patients and the SE cases had similar demographic characteristics, such as sex, race, and age, and also had similar etiologies. The majority (93%) of SE cases required anticonvulsant (AED) treatment to control and stop seizure activity. In the 10- to 29-min group, 43% stopped seizing spontaneously, and the remainder (57%) required AED treatment to stop seizure activity. The mortality for the SE patients was 19% compared with 2.6% for 10- to 29-min group (p<0.001). In the 10- to 29-min group that stopped seizing spontaneously, the mortality was 0. In the 10- to 29-min patients that required AED treatment, the mortality was 4.4%. CONCLUSIONS: The results demonstrate that a significant number of patients experience seizure activity lasting from 10- to 29-min. Approximately half of these seizure events stopped spontaneously and did not require AED treatment. The other half of the patients responded quickly to medications and stopped seizing before the 30-min definition for SE. The overall mortality of this group was significantly lower than that of the patients with SE. The results demonstrate that further studies on the 10- to 29-min seizure group are needed to differentiate seizures that will stop spontaneously and those that will only stop with AED treatment. Because almost half of the prolonged seizures stopped spontaneously, further studies are needed before including prolonged seizure activity in the definition of SE.     

Anticonvulsant combination therapy: rational concepts versus real effectiveness

Primary drug treatment of epilepsies is usually a monotherapy with an antiepileptic drug. This procedure causes less side effects as polytherapy and probably shows the same efficacy. Two third of patients with focal epilepsies are sufficiently treated with a single antiepileptic drug: 60% of patients with Grand mal and 22-30% of patients with complex focal seizures remain seizures free. An alternative monotherapy will suppress seizures in another 30% of patients. With polytherapy this is achieved in only 12% of the remaining patients, furthermore, side effects increase in polytherapy. Generalized epilepsies are usually treated with valproate monotherapy. Patients remain seizure free from absence in 60-90%, from myoclonic-impulsive seizures in 75-97% and from Grand mal in about 85%. Alternative monotherapy is less common because of the limited efficacy and possible side effects of drugs: ethosuximide does not control Grand mal and phenobarbitone may cause sedation. Thus, polytherapy is commonly initiated when monotherapy fails to control seizures (lamotrigine is often chosen as comedication). Rational polypharmacy is a term suggesting rational concepts in planning antiepileptic polytherapy leading to a superior anticonvulsant effect. However, this consideration is not based on or supported by clinical data. Yet, a combination of drugs which have no or little pharmacokinetic interactions seems to be a clinically relevant recommendation. Thus, newly developed drugs such as vigabatrin, lamotrigine or gabapentin are more frequently used as comedication with standard antiepileptic drugs.     

Prevalence, classification, and severity of epilepsy and epileptic syndromes in children

PURPOSE: To determine the point prevalence of active childhood epilepsy in a defined area and evaluate the usefulness of ILAE classification of seizures, and epilepsies/syndromes with special interest in severe epilepsies. METHODS: By using the latest ILAE International Classification of Epileptic Seizures (ICES, 1981) and Epilepsies and Epileptic Syndromes (ICE, 1989), we determined the age- and sex-specific prevalence rates of epilepsy, type of seizures, epilepsies, and recognizable epileptic syndromes, as well as the proportion of severe cases in each seizure/epilepsy/syndrome category in all children 0-15 years of age from a geographically defined area in Finland. All medical records, neurophysiological recordings and available clinical data were reviewed retrospectively. RESULTS: Point prevalence of active epilepsy on December 12, 1992 was 3.94 per 1,000. According to ICES/ICE, we were able to classify 96% of seizures and 90% of epilepsies and syndromes. Generalized seizure and epilepsy/syndrome types were more prevalent in children 0-6 years of age and partial/localization-related in children 6-15 years of age. Epilepsy was intractable in 17% of all cases and correlated significantly with symptomatic etiology and early onset of epilepsy, as well as with additional neuroimpairments. CONCLUSIONS: A considerable number of cases fell into the nonspecific categories of ICE, which limits the value of present epilepsy/syndrome classification in terms of prognosis, prediction, and indication for special investigations in individual cases. A number of intractable cases was relatively low, indicating good prognosis in many childhood epilepsies, especially when additional neuroimpairments are absent.     

Prolonged video EEG monitoring in differential diagnosis of seizures and in presurgical epilepsy diagnosis]

Prolonged video-EEG-monitoring facilitates a correlation of clinical seizure semiology and corresponding EEG changes. Indications for prolonged video-EEG-monitoring comprise differential diagnosis of epileptic and psychogenic seizures, correct classification of epileptic syndromes and presurgical evaluation of patients with medically refractory focal epilepsies. 6000 patients in Austria would benefit from epilepsy surgery with an additional 150 bis 200 new patients appearing each year. Presurgical evaluation consists of a non-invasive Phase I and an invasive Phase II. During Phase I each patient is evaluated with a prolonged video-EEG-monitoring with scalp-EEG, a MRI-scan, a SPECT- and/or PET-scan, a neuropsychological evaluation and a Wada-test. If the epileptogenic zone cannot be localized adequately with these methods, invasive electrophysiological techniques with intracranial (epidural peg-electrodes, foramen-ovale electrodes, subdural strip or grid electrodes) or intracerebral electrodes (stereotaxically implanted depth electrodes) have to be applied. Epilepsy surgery renders 70 to 80% of patients seizure free and thus can regarded an effective and safe treatment option for patients with medically refractory focal epilepsies.