Candidates For Epilepsy Surgery Research Articles

Investigatory pathway and principles of patient selection for epilepsy surgery candidates: a systematic review

BackgroundThe predominant treatment for epilepsy is pharmacotherapy, yet 20–40% do not respond to anti-epileptic drugs. After becoming pharmacoresistant, some patients are worked-up to determine candidacy for epilepsy surgery. Despite the 2009 American Epilepsy Society guidelines, there is no broadly accepted criteria for the investigatory pathway and principles of patient selection for epilepsy surgery candidates. The objective of this systematic review is to elucidate what diagnostic pathways clinicians globally utilize.MethodsUtilizing the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) and the Cochrane Handbook of Systemic Reviews of Interventions, we conducted a systematic review through MEDLINE, Embase, and CENTRAL.ResultsFrom 2092 screened articles, 14 met inclusion criteria for qualitative synthesis. Structural MRI was required in all investigatory pathways. All but two articles required neuropsychological assessment. Six required neuropsychiatric assessment. Two protocols mentioned assessing the patient’s support network. Three other protocols mentioned discussing expectations with patients. One also motioned conducing an occupational evaluation and making all surgery decisions in a multidisciplinary management conference. fMRI and the Wada test were required assessments in seven of the protocols. [18F]FDG-PET and SPECT were ancillary for all but three articles (where they were required). MEG and intracranial EEG were only mentioned as ancillary. Magnetic resonance (MR) spectroscopy was required at two institutes. With regards to the actual indication for selecting patients to begin the investigatory pathway, seven of the articles used a variation of the International League Against Epilepsy definition of refectory epilepsy, while one incorporated patient social history.ConclusionsDespite attempts to standardize patient selection and investigatory pathways, no two protocols were identical. Scalp video/EEG telemetry, structural MRI, and neuropsychological assessment were the only assessments utilized in nearly all protocols. Socioeconomic restrictions appear to play a role in determining which tests are utilized in the investigatory pathway—not just for developing countries. However, cost-effective assessments, such as assessing patient support network and providing realistic expectation of outcomes, were only utilized in few protocols. In addition, no advanced imaging technologies (i.e., qMRI, 3D-MMI) were utilized. Overall, even amongst expert examiners there is significant variation throughout epilepsy centers globally, in selecting candidates and working up patients.

Non-Pharmacological and Non-Surgical Treatment of Refractory Childhood Epilepsy.

Nearly 20-40% of patients with epilepsy are likely to have drug resistant epilepsy (DRE). Add-on antiseizure drugs do not produce optimal seizure control in these patients. Among the non-pharmacological options, only resective surgery is curative. However, a large majority of patients are not candidates for resective epilepsy surgery. For these children with DRE, non-pharmacological non-surgery "palliative" options should be considered early than late. These include dietary therapies and neuromodulation. While there are numerous clinical trials supporting the efficacy of dietary therapies (viz ketogenic diet, modified Atkins diet and low glycemic index therapy), the evidence for neuromodulation is still evolving. Neuromodulation techniques include vagal nerve stimulation, deep brain stimulation, and transcranial magnetic stimulation. Each of the options, whether diet or neuromodulation, has its own advantages, disadvantages and adverse events profile. These have to be considered and discussed with the family before deciding the modality being chosen.

Neuropsychological assessment protocol for adults in epilepsy surgery

Refractory epilepsy means that the seizures are untreatable, and therefore one of the interventions that makes it possible to eliminate them or to accomplish a reduction in the number of seizures is neurosurgery. A neuropsychological evaluation model aimed at measuring the cognitive performance of adult patients who are candidates for epilepsy surgery is proposed. In line with the proposals most frequently put forward by the various reference centres for epilepsy, an open protocol is proposed that is aimed at obtaining a baseline of overall cognitive performance, cognitive reserve and manual dominance, as well as cognitive processes such as attention, language, visuoconstructive and manipulative skills, memory and executive functions, among others, without neglecting the psychopathological examination and the patient's quality of life. This, together with the results of other diagnostic specialities, will contribute to the localisation and minimisation of the cognitive sequelae secondary to the surgical intervention on the epileptic focus, as well as to providing information to the medical team responsible for the case and to patients and relatives about the possibilities and prognosis of the intervention. It is necessary to have a battery of techniques and an adequate consensus when evaluating the data obtained. An assessment model is proposed that allows information to be obtained about the neuropsychological profile of the candidate for epilepsy surgery, which is open to debate and serves as a model for discussion by the other epilepsy reference centres.

Establishing a Developmentally Appropriate fMRI Paradigm Relevant to Presurgical Mapping of Memory in Children

Functional magnetic resonance imaging (fMRI) is an established eloquent cortex mapping technique that is now an integral part of the pre-operative work-up in candidates for epilepsy surgery. Emerging evidence in adults with epilepsy suggests that material-specific fMRI paradigms can predict postoperative memory outcomes, however these paradigms are not suitable for children. In pediatric age, the use of memory fMRI paradigms designed for adults is complicated by the effect of developmental stages in cognitive maturation, the impairment experienced by some people with temporal lobe epilepsy (TLE) and the normal representation of memory function during development, which may differ from adults. We present a memory fMRI paradigm designed to activate mesial temporal lobe structures that is brief, independent of reading ability, and therefore a novel candidate for use in children. Data from 33 adults and 19 children (all healthy controls) show that the paradigm captures the expected leftward asymmetry of mesial temporal activation in adults. A more symmetrical pattern was observed in children, consistent with the progressive emergence of hemispheric specialisation across childhood. These data have important implications for the interpretation of presurgical memory fMRI in the pediatric setting. They also highlight the need to carefully consider the impact of cognitive development on fMRI tools used in clinical practice.

Prospective validation of a machine learning model that uses provider notes to identify candidates for resective epilepsy surgery.

Delay to resective epilepsy surgery results in avoidable disease burden and increased risk of mortality. The objective was to prospectively validate a natural language processing (NLP) application that uses provider notes to assign epilepsy surgery candidacy scores. The application was trained on notes from (1) patients with a diagnosis of epilepsy and a history of resective epilepsy surgery and (2) patients who were seizure-free without surgery. The testing set included all patients with unknown surgical candidacy status and an upcoming neurology visit. Training and testing sets were updated weekly for 1 year. One- to three-word phrases contained in patients' notes were used as features. Patients prospectively identified by the application as candidates for surgery were manually reviewed by two epileptologists. Performance metrics were defined by comparing NLP-derived surgical candidacy scores with surgical candidacy status from expert chart review. The training set was updated weekly and included notes from a mean of 519±67 patients. The area under the receiver operating characteristic curve (AUC) from 10-fold cross-validation was 0.90±0.04 (range = 0.83-0.96) and improved by 0.002 per week (P<.001) as new patients were added to the training set. Of the 6395 patients who visited the neurology clinic, 4211 (67%) were evaluated by the model. The prospective AUC on this test set was 0.79 (95% confidence interval [CI] = 0.62-0.96). Using the optimal surgical candidacy score threshold, sensitivity was 0.80 (95% CI = 0.29-0.99), specificity was 0.77 (95% CI = 0.64-0.88), positive predictive value was 0.25 (95% CI = 0.07-0.52), and negative predictive value was 0.98 (95% CI = 0.87-1.00). The number needed to screen was 5.6. An electronic health record-integrated NLP application can accurately assign surgical candidacy scores to patients in a clinical setting.

Epileptogenicity Maps of Intracerebral Fast Activities (60-100 Hz) at Seizure Onset in Epilepsy Surgery Candidates.

Fast activities (FA) at seizure onset have been increasingly described as a useful signature of the epileptogenic zone (EZ) in patients undergoing intracranial EEG recordings. Different computer-based signal analysis methods have thus been developed for objectively quantifying ictal FA. Whether these methods detect FA in all forms of focal epilepsies, whether they provide similar information than visual analysis (VA), and whether they might help for the surgical decision remain crucial issues. We thus conducted a retrospective study in 21 consecutive patients suffering from drug-resistant seizures studied by SEEG recordings. Ictal FA were quantified using the Epileptogenicity Maps (EM) method that we recently developed and which generates, by adopting a neuroimaging approach, statistical parametric maps of FA ranging from 60 to 100 Hz (FA60−100). Ictal FA were analyzed blindly using VA and EM, and the prognostic significance of removing areas exhibiting FA60−100 at seizure onset was evaluated. A significant ictal FA60−100 activation was found in all patients, and in 92.6% of all the 68 seizures recorded, whatever the epilepsy type. The overlap ratio (OR) between VA and EM was significantly better for defining the regions spared at seizure onset than those from which seizure arose (p < 0.001), especially in temporal or temporal “plus” epilepsies. EM and VA were much more discordant to define the EZ, with a mean number of electrode contacts involved at seizure onset significantly higher with EM than with VA (p = <0.0001). Seizure outcome correlated with the resection ratio for FA60−100, which was significantly higher in seizure-free (Engel's class Ia) than in non seizure-free patients (class Ic-IV) (p = 0.048). The quantification of FA at seizure onset can bring information additional to clinical expertise that might contribute to define accurately the cortical region to be resected.

Uncovering homonymous visual field defects in candidates for pediatric epilepsy surgery.

Perimetry in children can be challenging due to low cooperation and short attention span. Especially during the pre-surgical work-up of children with pharmaco-refractory epilepsies, however, diagnosing homonymous visual field defects (HVFDs) can be crucial for planning surgical strategies. Here, we evaluated "campimetry" for visual field testing in children. Furthermore, we analyzed strabismus and anomalous head posture as clinical signs for HVFDs. Campimetry and a standard orthoptic examination were performed in 18 patients (age range: 3y 2m-18y) who underwent epilepsy surgeries in our center during the study period, and in 11 additional patients (age range: 2y 10m-22y 10m) with suspected or confirmed HVFDs. In 16/18 patients of our unselected surgery cohort, pre- and postoperative campimetry was successfully completed. Of these, only 7/16 patients had intact visual fields pre- and postoperatively, while 5/16 patients already showed preoperative HVFDs and 4/16 patients suffered newly acquired HVFDs as calculated consequences of the surgery. Regarding clinical signs, strabismus (mostly esotropia) and anomalous head posture were specific indicators of HVFDs (strabismus: 6/12 with HVFDs vs 1/18 without; anomalous head posture: 8/12 with HVFDs vs 0/18 without). For perimetry in children with limited cooperation, we suggest campimetry as it allows early detection and fast delineation of HVFDs. This is particularly important in pediatric epilepsy surgery patients, who display a surprisingly high proportion of HVFDs (9/16). Both, strabismus and anomalous head posture can indicate such HVFDs. Therefore, clinicians should pay attention to these clinical signs, especially in the context of epilepsy surgery.

Implications of genetic diagnostics in epilepsy surgery candidates: A single-center cohort study.

ObjectiveGenetic causes are increasingly identified in patients with focal epilepsy. These genetic causes may be related to the effectiveness of epilepsy surgery. We aimed to assess the use and yield of genetic testing in a large cohort of patients who were evaluated for epilepsy surgery.MethodsWe performed a retrospective single‐center consecutive cohort study of patients who were evaluated for surgery between 1990 and 2016. Within this cohort, we assessed the use of genetic testing—either before or after presurgical decision‐making. We evaluated genetic results as well as the outcome of presurgical decision‐making and surgery, and compared these end points for different subgroups—especially MRI‐positive vs MRI‐negative patients. Patients with tuberous sclerosis (TSC) and KRIT1 mutations were excluded from analysis.ResultsOf the 2385 epilepsy patients who were evaluated for surgery, 1280 (54%) received surgical treatment in our center. Of the entire cohort, 325 (14%) underwent genetic testing, comprising 156 of 450 MRI‐negative patients (35%) vs 169 of 1935 MRI‐positive patients (9%). A genetic cause of epilepsy was found in 40 of the 325 patients (12%, 2% of the entire cohort), mainly consisting of mutations in ion channel function and synaptic transmission genes, and mTOR pathway gene mutations. Three of the seven patients with mTOR pathway gene mutations underwent surgery; two achieved complete seizure freedom. One of the 17 patients with germline mutations in ion channel function and synaptic transmission genes received resective surgery but was not rendered seizure‐free; two other patients underwent invasive intracranial EEG‐monitoring before being rejected.SignificanceThis study shows that genetic testing is increasingly applied in focal epilepsy patients who are considered for epilepsy surgery. The diagnostic yield of genetic testing is highest in next generation sequencing techniques, and the outcome of genetic testing assists selecting eligible patients for invasive intracranial monitoring and resective surgery.

Cognitive performance in distinct groups of children undergoing epilepsy surgery-a single-centre experience.

BackgroundWe aimed first to describe trends in cognitive performance over time in a large patient cohort (n = 203) from a single tertiary centre for paediatric epilepsy surgery over the period of 16 years divided in two (developing—pre-2011 vs. established—post-2011). Secondly, we tried to identify subgroups of epilepsy surgery candidates with distinctive epilepsy-related characteristics that associate with their pre- and post-surgical cognitive performance. Thirdly, we analysed variables affecting pre-surgical and post-surgical IQ/DQ and their change (post- vs. pre-surgical).MethodsWe analysed IQ/DQ data obtained using standardized neuropsychological tests before epilepsy surgery and one year post-surgically, along with details of patient’s epilepsy, epilepsy surgery and outcomes in terms of freedom from seizures. Using regression analysis, we described the trend in post-operative IQ/DQ. Cognitive outcomes and the associated epilepsy- and epilepsy surgery-related variables were compared between periods before and after 2011. Using multivariate analysis we analysed the effect of individual variables on pre- and post-operative IQ/DQ and its change.ResultsEpilepsy surgery tends to improve post-surgical IQ/DQ, most significantly in patients with lower pre-surgical IQ/DQ, and post-surgical IQ/DQ strongly correlates with pre-surgical IQ/DQ (Rho = 0.888, p < 0.001). We found no significant difference in pre-, post-surgical IQ/DQ and IQ/DQ change between the periods of pre-2011 and post-2011 (p = 0.7, p = 0.469, p = 0.796, respectively). Patients with temporal or extratemporal epilepsy differed in their pre-surgical IQ/DQ (p = 0.001) and in IQ/DQ change (p = 0.002) from those with hemispheric epilepsy, with no significant difference in post-surgical IQ/DQ (p = 0.888). Groups of patients with different underlying histopathology showed significantly different pre- and post-surgical IQ/DQ (p < 0.001 and p < 0.001 respectively) but not IQ/DQ change (p = 0.345).Variables associated with severe epilepsy showed effect on cognitive performance in multivariate model.DiscussionPost-surgical IQ/DQ strongly correlates with pre-surgical IQ/DQ and greatest IQ/DQ gain occurs in patients with lower pre-surgical IQ/DQ scores. Cognitive performance was not affected by changes in paediatric epilepsy surgery practice. Pre- and post-operative cognitive performances, as well as patients’ potential for cognitive recovery, are highly dependent on the underlying aetiology and epileptic syndrome.

Epilepsy surgery in Indonesia: Achieving better result with limited resources

Background: Even with modern medication, 30 to 40% of epilepsy patients will be intractable and this condition leads to cognitive and psychosocial decline, resulting in worse quality of life and higher mortality. With 0.5–0.6% prevalence, there will be about 1.5 million epileptic in Indonesia, about 440.000 will be intractable, and 220.000 of them are potential candidates for epilepsy surgery (ES). A decade has passed since the first ES performed on July 1999, and the number increases every year reaching 35–47 ES per year in 2007–2009. Despite the excellent result shown, all of these ES were still performed in Semarang (Diponegoro University) while the patients were from all part of Indonesia. The major reason behind the unavailability of ES in most part of the country should be discussed for the sake of future development of ES in Indonesia.&#x0D; Material: Epilepsy surgery was started in July 1999 with anterior temporal lobectomy for a 34 Y-old female with left mesial temporal sclerosis (MTS) causing a long standing intractable seizures. The number of cases increases every year. Until the end of 2009, there were 238 cases of epilepsy surgery, including 212 anterior temporal lobectomies. Among these, 106 cases had been follow up more than 36 months, and evaluated for surgical results.&#x0D; Methods: To evaluate the patient's selection and the presurgical evaluation, we divide the ES cases into the first 5 years (56 cases) and the recent 5 years (182 cases). But for the purpose of evaluating surgical results, only those with at least 36 months postoperative follow-up were included (106 cases) and grouped into those operated before or after the age of 25 Y-old (group A and group B), and into those operated before or after the length of epilepsy of 10 years (group I and group II).&#x0D; Results: For the first five years-period, decision to operate were based on MRI and routine interictal EEG in 54 out of 56 TLE cases. One patient had long-term ictal EEG and another had subdural grid EEG implanted, since MRI in both patients showed visually normal MRI. For the last five years, decision to operate were based on MRI and routine EEG in 91 out of 156 TLE cases. Long term ictal EEG were performed in 46 patients, subdural grid EEG in 10 patients, PET study in 7 patients, and EcoG in 2 patients. The overall seizure free (SF) rate were 70.75%, but if grouped according to patient's age at surgery (less than or over 25 Y-old), the SF rates were 75.4% vs 66.04% respectively. So did if grouped according to length of disease (less than or more than 10 years), the SF rates were 78.72% vs 64.40% respectively.&#x0D; Conclusion: MRI plays very important role to decide the side of the epileptic temporal side, but this role is decreasing as it was 96.4% during the beginning five years to become 58.34% for the last five years. This means that we are working on more difficult epilepsy cases recently. SF rate was significantly higher for those who was operated at younger age and for those with shorter duration of epilepsy. This means that surgery should be offered earlier for those intractable TLE patients with obvious focus on MRI.

Desperately needed in Indonesia: Basic Epilepsy Surgery Centers with Simple but Reliable pre-surgical investigations, based on Semarang’s Experience

Background: Even with optimized anti-epileptic medications, 30% of epilepsy patients will be refractory and this condition leads to cognitive and psychosocial decline, resulting in worse quality of life and higher mortality. With 0,75% prevalence, there are more than 2.0 million epileptic in Indonesia, about 360.000 will be refractory, and half of them are potential candidates for epilepsy surgery (ES). After 17 years since the first ES on July 1999, number of ES increases every year reaching around 50 cases per year. By the end of 2017,  the total number reached 615 and most was temporal lobe epilepsy (TLE) cases. Pre-surgical investigations were compared in relation to the seizure free results between the first five-year and the recent twelve-year. Despite the excellent result shown, all of these ES were still performed in Semarang (Diponegoro University), and demographic analysis showed that 80% patients came from Java-Bali area. So that new basic centers capable of performing ES for simple TLE cases are desperately needed to improve treatment for refractory epilepsy cases elsewhere.Material and methods: Until the end of 2017, there were 615 ES cases, including 514 Temporal Lobe Epilepsies (TLEs). Pre-surgical investigations were grouped as Simple (MRI with specific protocol and routine EEG), Difficult (needs long-term ictal EEG, and /or PET CT), and Complex (needs invasive or intracranial/ subdural grid EEG, and or Electrocorticography/ ECoG during the surgery). For the first five year-period, besides seizure semiology, decision to operate were based on MRI and routine EEG (Simple) in 54 out of 56 (96,4%) TLE cases. One patient had long-term ictal EEG and another had subdural grid EEG implanted, both patients showed visually normal MRI. But for the recent twelve-year, Simple TLEs occupy only 234 out of 458 (51%) TLE cases. Long-term ictal EEG were performed in 161 patients (35,2%), PET study in 39 patients (8,5%), subdural grid EEG in 30 patients (6,5%), and ECoG in 61 patients (13,3%).Results: As a new ES center performing only simple TLE cases, our surgical results were Class I: 82%, Class II: 11%, and Class III: 7% (9). As a semi advance ES center (after more than 5 years, and only half were simple ES cases), the Class I or seizure free results were 78,7% for simple TLEs, 73,4% for Difficult TLEs, and 65,2% for Complex TLEs.            Demographic distribution showed that almost 80% of ES patients came from Java-Bali area, and half of them were from Central Java Province with Semarang as its capital. Patients from other parts of the country were scarce, especially from remotely located islands of East Indonesia.Conclusion: For the first five year, -as a basic ES center- we relay most on good MRI besides detailed study on seizure semiology and routine EEG. The Class I or Seizure Free result was best in the Simple TLEs with MRI showing discrete unilateral lesion in the temporal lobe. With 17 years experience, and a structured ES program including those patients needed invasive pre-surgical investigations, Semarang is a semi-advance center capable for research and training. This fact should encourage hospitals with micro-neurosurgical capabilities to initiate a new Basic ES Center by sending their neurologist and neurosurgeon to Semarang, so that ES services may become available to PWEs in all part of Indonesia.

Electroencephalography in epilepsy: look for what could be beyond the visual inspection.

Since its starting point in 1929, human scalp electroencephalography (EEG) has been routinely interpreted by visual inspection of waveforms using the assumption that the activity at a given electrode is a representation of the activity of the cerebral cortex under it, but such a method has some limitations. In this review, we will discuss three advanced methods to obtain valuable information from scalp EEG in epilepsy using innovative technologies. Authors who had previous publications in the field provided a narrative review. Spike voltage topography of interictal spikes is a potential way to improve non-invasive EEG localization in focal epilepsies. Electrical source imaging is also a complementary technique in localization of the epileptogenic zone in patients who are candidates for epilepsy surgery. Quantitative EEG simplifies the large amount of information in continuous EEG by providing a static graphical display. Scalp electroencephalography has the potential to offer more spatial and temporal information than the traditional way of visual inspection alone in patients with epilepsy. Fortunately, with the help of modern digital EEG equipment and computer-assisted analysis, this information is more accessible.

Changing concepts in presurgical assessment for epilepsy surgery.

Candidates for epilepsy surgery must undergo presurgical evaluation to establish whether and how surgical treatment can stop seizures without causing neurological deficits. Various techniques, including MRI, PET, single-photon emission CT, video-EEG, magnetoencephalography and invasive EEG, aim to identify the diseased brain tissue and the involved network. Recent technical and methodological developments, encompassing both advances inexisting techniques and new combinations of technologies, are enhancing the ability to define the optimal resection strategy. Multimodal interpretation and predictive computer models are expected to aid surgical planning and patient counselling, and multimodal intraoperative guidance is likely to increase surgical precision. In this Review, we discuss howthe knowledge derived from these new approaches is challenging our way of thinking about surgery to stop focal seizures. In particular, we highlight the importance of looking beyond the EEG seizure onset zone and considering focal epilepsy as a brain network disease in which long-range connections need to be taken into account. We also explore how new diagnostic techniques are revealing essential information in the brain that was previously hidden from view.

Personality patterns of people with medically refractory epilepsy – Does the epileptogenic zone matter?

ObjectivesThe aims of this study were to determine the rate of dysfunctional personality patterns before and after epilepsy surgery, their types, and the importance of the epileptogenic zone in a sample of people with refractory epilepsy. MethodsWe conducted an ambispective observational study, including refractory epilepsy surgery candidates. Demographic, psychiatric, and neurological data were recorded. Evaluation of personality was made using the Millon Clinical Multiaxial Inventory-II (MCMI-II). Presurgical predictors of personality patterns were determined using a linear regression model. The proportion of patients with dysfunctional personality patterns, before and after surgery, was compared using the Mcnemar's test. Then a generalized estimating equation model was performed to include predictors of changes in this rate. ResultsOne hundred and ninety-nine participants were included. Seventy percent had a dysfunctional personality pattern before surgery. After surgery, this percentage dropped to 58%. The difference was statistically significant after adjusting for potential confounders (p = 0.013). The most common types were Cluster C personality patterns. Temporal epileptogenic zone was a significant predictor of higher scores of the Avoidant (Coef. 11.8; Confidence Interval (CI) −0.59 23.7; p = 0.051) and Compulsive (Coef. 9.55; CI 2.48 16.6; p = 0.008) personality patterns and lower scores of Histrionic (Coef. −11.4; CI −21.2 −1.55; p = 0.024) and Antisocial (Coef. −8.4; CI −15.6 −1.25; p = 0.022) personality patterns, compared to extratemporal epileptogenic zone. ConclusionPeople with refractory epilepsy have high rates of dysfunctional personality patterns. These patterns differ according to the epileptogenic zone.

Psychiatric Residue of Epilepsy Surgery: De Novo or Not.

The aim of this study was to determine the potential risk factors for de novo psychiatric syndromes after epilepsy surgery. Refractory epilepsy surgery candidates were recruited from our Refractory Epilepsy Reference Centre. Psychiatric evaluations were made before surgery and every year, during a 3-year follow-up period. Demographic, psychiatric, and neurological data were recorded. The types of surgeries considered were resective surgery (resection of the epileptogenic zone) and palliative surgery (deep brain stimulation of the anterior nuclei of the thalamus [ANT-DBS]). A survival analysis model was used to determine pre- and postsurgical predictors of de novo psychiatric events after surgery. One hundred and six people with refractory epilepsy submitted to epilepsy surgery were included. Sixteen (15%) people developed psychiatric disorders that were never identified before surgery. Multilobar epileptogenic zone (P = .001) and DBS of the ANT-DBS (P = .003) were found to be significant predictors of these events. People with more generalized epileptogenic activity and those who undergo ANT-DBS seem to present an increased susceptibility for the development of mental disorders, after neurosurgical interventions, for the treatment of refractory epilepsy. People considered to be at higher risk should be submitted to more frequent routine psychiatric assessments."

Indications and expectations for neuropsychological assessment in epilepsy surgery in children and adults.

In our first paper in this series (Epilepsia 2015; 56(5): 674-681), we published recommendations for the indications and expectations for neuropsychological assessment in routine epilepsy care. This partner paper provides a comprehensive overview of the more specialist role of neuropsychological assessment in the pre and postoperative evaluation of epilepsy surgery patients. The paper is in two parts. The first part presents the framework for the mandatory role of neuropsychologists in the presurgical evaluation of epilepsy surgery candidates. A preoperative neuropsychological assessment should be comprised of standardised measures of cognitive function in addition to wider measures of behavioural and psychosocial function. The results from the presurgical assessment are used to: (1) establish a baseline against which change can be measured following surgery; (2) provide a collaborative contribution to seizure characterization, lateralization and localization; (3) provide evidence-based predictions of cognitive risk associated with the proposed surgery; and (4) provide the evidence base for comprehensive preoperative counselling, including exploration of patient expectations of surgical treatment. The second part examines the critical role of the neuropsychologist in the evaluation of postoperative outcomes. Neuropsychological changes following surgery are dynamic and a comprehensive, long-term assessment of these changes following surgery should form an integral part of the postoperative follow-up. The special considerations with respect to pre and postoperative assessment when working with paediatric populations and those with an intellectual disability are also discussed. The paper provides a summary checklist for neuropsychological involvement throughout the epilepsy surgery process, based on the recommendations discussed.

P29-T Mapping primary motor cortex with navigated TMS in unusual corticospinal lateralization for epilepsy surgery

Background The corticospinal tract has a sequential development in which the ipsilateral projections are gradually withdrawn, whereas the contralateral projections persist. A unilateral lesion in the motor cortex during early life may cause a reorganization in this process with preservation of uncrossed corticospinal connections in the spared hemisphere. As a result, all the motor function is lateralized in one hemisphere. Individuals with this kind of lesions also have an increased risk of drug-resistant epilepsy and may be candidates for epilepsy surgery. In these cases, it is important to evaluate the motor function for surgical treatment. Material and methods We present a series of 4 patients with pharmacoresistant epilepsy and early-life primary motor cortex lesion that were studied for epilepsy surgery. We used nTMS to investigate if there was still functional motor activity in one or both frontal cortices. Results In three cases there was no activity in the pathological cortex obtaining a bilateral response in the normal cortex. Two of them underwent fMRI using a motor task showing bilateral motor cortical function in one patient, and unilateral activation of ipsilateral motor cortex in the other patient. The last patient showed a crossed response. Two patients were operated without new postoperative deficits. Conclusions nTMS helps to define unusual lateralization of motor cortex and to guide a secure resection with the least motor deficits.

Establishment of low cost epilepsy surgery centers in resource poor setting

PurposeTo prospectively assess the feasibility of establishing low cost epilepsy surgery programs in resource poor settings. MethodWe started epilepsy surgery centers in Tier 2 and Tier 3 cities in India in private hospitals. This model is based on the identifying and operating ideal epilepsy surgery candidates on the basis of clinical history, interictal and ictal video-EEG data, and 1.5 T MRI without other investigations and without regular involvement of other specialists. Trained epileptologists formed the fulcrum of this program who identified ideal candidates, offered them counseling, and read video-EEG and MRI. We also spread epilepsy awareness among locals and physicians and established focused epilepsy clinics. The expenses were subsidized for deserving patients and policies were devised to keep video-EEG duration and staff requirement to minimum. Difficult epilepsy surgery cases were referred to established centers. Initial surgeries were performed by invited epilepsy surgeons and subsequently by local neurosurgeons. ResultsA total of 125 epilepsy surgeries were performed at three centers since 2012. This included 81(64.8%) temporal lobe resections, 26 (20.8%) extratemporal focal resections, and 13 (10.4%) hemispherotomies. Of the 93 patients with more than 1 year of postoperative followup, 86 (92.5%) had Engel class IA outcome. There were minor complications in 5% patients. Average cost of presurgical evaluation and surgery was Rs. 92,707 (USD 1,324). ConclusionsIt is possible to establish successful epilepsy surgery programs in resource poor setting with reasonable costs. This low cost model can be replicated in other parts of world to reduce the surgical treatment gap.

Surgical outcomes and prognostic factors of drug-resistant epilepsy secondary to encephalomalacia.

To evaluate long-term outcomes and prognostic factors in patients who underwent surgical resection for drug-resistant epilepsy secondary to encephalomalacia. A total of 143 patients with drug-resistant epilepsy who underwent surgical resection with a follow-up of at least 5years were included. Seizure outcomes were evaluated based on the International League Against Epilepsy classification. Univariate analysis and a multivariate logistic regression model in a backward fashion were used to identify the potential predictors of seizure outcomes. Three months after surgery, 102 of 143 (71.3%) patients had achieved favorable seizure outcomes. Five years after surgery, 107 of 143 (74.8%) patients had achieved favorable seizure outcomes. Changes in the postoperative seizure status were observed in 22 of 143 (15.4%) patients during follow-up, but the difference in the seizure-free rate between 3months and 5years after surgery was not significant. Univariate and multivariate analyses revealed that only a monthly seizure frequency of >30 seizures (odds ratio = 3.42, 95% confidence interval = 1.19-9.76) and bilateral ictal onset rhythms (odds ratio = 4.46, 95% confidence interval = 1.61-12.39) were independent predictors of unfavorable seizure outcomes. Surgical resection is an effective treatment for patients with drug-resistant epilepsy secondary to encephalomalacia. Knowledge of the predictors of seizure outcomes may help during preoperative counseling and selection of optimal candidates for epilepsy surgery among patients with drug-resistant epilepsy secondary to encephalomalacia.

Emotional asymmetries in refractory medial temporal and frontal lobe epilepsy: Their impact on predicting lateralization and localization of seizures

BackgroundEmotional disturbances have been reported in patients with epilepsy. Although conflicting results emanate from relevant studies, depressive symptoms are seen more often in temporal lobe epilepsy (TLE) whereas, hypomanic/manic symptoms usually accompany frontal lobe epilepsy (FLE); the above psychiatric symptoms are especially seen in refractory epilepsy. However, neocortical TLE and medial TLE are considered as distinct epileptic syndromes, and there is limited literature on comparison of affective traits in medial TLE (MTLE) and FLE. AimIn the present study, we sought to investigate affective traits among epilepsy surgery candidates suffering refractory left medial TLE (LMTLE), right medial TLE (RMTLE), left FLE (LFLE), and right FLE (RFLE). ResultsOur results revealed that patients with MTLE scored significantly higher than the ones with FLE in depression, anxiety, asthenia, and melancholia as measured by the Symptoms Rating Scale for Depression and Anxiety (SRSDA), while patients with FLE scored significantly higher in mania than those with MTLE. Moreover, patients with MTLE scored significantly higher than their FLE counterparts on the anxiety scale of the State Trait Personality Inventory (STPI)-trait version. When laterality of the seizure focus was taken into account, no differences were found among both patients with MTLE and patients with FLE, with exception for the Trail Making Test part B (TMT-B) in which patients with RMTLE performed significantly worse than patients with LMTLE. Seizure frequency was higher for FLE. ConclusionsWe provide evidence for an anterior-frontal versus a posterior-medial temporal cerebral functional asymmetry with regard to the manifestation of manic and depressive emotional traits in FLE and MTLE, respectively. Our results are mainly discussed within the frame of their contribution in localizing and to a lesser extent in lateralizing seizures foci in epilepsy surgery candidates. We suggest that this is of great importance in the context of preoperative monitoring of epilepsy surgery, especially when neuropsychologists are called upon to provide anatomical information in defining the functional deficit zone.