Practice parameter: temporal lobe and localized neocortical resections for epilepsy: report of the Quality Standards Subcommittee of the American Academy of Neurology, in association with the American Epilepsy Society and the American Association of Neurological Surgeons

Atypical neuropsychological profiles and cognitive outcome in mesial temporal lobe epilepsy

Patients with left mesial temporal lobe epilepsy (MTLE) have deficits in verbal memory processes, while patients with right MTLE have visuospatial memory impairment. However, atypical cognitive phenotypes among patients with MTLE may occur. In this study, we analyzed preoperative memory deficits in a cohort of 426 right-handed patients with unilateral MTLE. We also evaluated the cognitive outcome after anterior temporal lobectomy (ATL) of patients with atypical profiles in comparison with those with typical memory profile. We found that 25% of our patients had a typical cognitive profile, with verbal memory deficits associated with left side hippocampal sclerosis (HS) and visuospatial memory deficits associated with right side HS. However, 75% of our patients had atypical memory profiles. Despite these atypical profiles, patients submitted to right ATL had no significant cognitive deficit after surgery. In patients submitted to left ATL, the higher the presurgical scores on verbal memory and naming tests, the higher the cognitive decline after surgery.

Moyamoya disease with mesial temporal sclerosis

The combination of moyamoya syndrome and symptomatic mesial temporal sclerosis (MTS) has not previously been reported. The authors present the case of a 5-year-old boy with symptomatic MTS who developed progressive moyamoya syndrome. This combination of progressive moyamoya and a structural seizure focus presented a unique clinical problem, with the natural history of MTS predicting a high likelihood of needing resection in the future, which could be challenging following any type of moyamoya-related revascularization surgery. In anticipation of this problem, the patient underwent resection of the right inferior and mesial temporal lobe followed by right pial synangiosis as a 1-day combined operation. Postoperatively he recovered well without any neurological deficits and had an uneventful hospital stay. This case of moyamoya is unique in its association with MTS, and for the simultaneous operations for pial synangiosis and temporal lobectomy, highlighting the importance of surgical planning in patients with dual pathological processes.

Machine learning approach for the outcome prediction of temporal lobe epilepsy surgery

Epilepsy surgery is effective in reducing both the number and frequency of seizures, particularly in temporal lobe epilepsy (TLE). Nevertheless, a significant proportion of these patients continue suffering seizures after surgery. Here we used a machine learning approach to predict the outcome of epilepsy surgery based on supervised classification data mining taking into account not only the common clinical variables, but also pathological and neuropsychological evaluations. We have generated models capable of predicting whether a patient with TLE secondary to hippocampal sclerosis will fully recover from epilepsy or not. The machine learning analysis revealed that outcome could be predicted with an estimated accuracy of almost 90% using some clinical and neuropsychological features. Importantly, not all the features were needed to perform the prediction; some of them proved to be irrelevant to the prognosis. Personality style was found to be one of the key features to predict the outcome. Although we examined relatively few cases, findings were verified across all data, showing that the machine learning approach described in the present study may be a powerful method. Since neuropsychological assessment of epileptic patients is a standard protocol in the pre-surgical evaluation, we propose to include these specific psychological tests and machine learning tools to improve the selection of candidates for epilepsy surgery.

Long-term surgical outcomes in patients with drug-resistant temporal lobe epilepsy and no histological abnormalities

INTRODUCTION

Reports on surgical outcomes in patients with drug-resistant temporal lobe epilepsy without histological abnormalities are scarce.

METHODS

Retrospective review of data from patients with drug-resistant temporal lobe epilepsy and no histopathological alterations who underwent anterior mesial temporal lobectomy. We analysed the following variables: age, sex, age at seizure onset, age at surgery, time elapsed between diagnosis and the date of the surgery, follow-up time, and classification according to the Engel rating scale.

RESULTS

From a database of 256 temporal lobectomies, 21 were identified as meeting the inclusion criteria. The average age upon diagnosis of epilepsy was 8.3 years and average age at time of surgery was 28.6 years. The mean time elapsed between diagnosis and surgery was 20.2 years. After a mean follow-up of 6.5 years, 90.5% of the patients showed favourable outcomes (classes i and ii) and 42.9% were seizure-free (class IA). Comparative analysis of the variables revealed that average age at seizure onset was the only statistically significant difference between groups, with age at onset being lower in patients with favourable outcomes.

CONCLUSION

Although long-term surgical outcomes were favourable for a large majority of patients, the percentage of seizure-free patients is lower than in patients with lesional epilepsy and comparable to that previously reported in the literature.

Early predictors of outcome in newly diagnosed epilepsy

Longitudinal studies of newly diagnosed epilepsy in children and adults have identified prognostic factors that allow early identification of patients whose seizures are likely to remain uncontrolled with antiepileptic medication. Results from outcome studies may be subject to bias, depending on the setting (community versus clinic), design (retrospective versus prospective) and characteristics of the patient cohort studied (age, types of epilepsy, specific comorbidities). Nevertheless, factors such as early response to medication, underlying aetiology, and number of seizures prior to initiation of treatment have consistently been found to be predictive of seizure outcomes. Other variables such as age, electroencephalographic findings and the presence or absence of psychiatric co-morbidities have been correlated with outcomes in some analyses. This review has examined studies of seizure outcomes in adults and children with newly diagnosed epilepsy identifying the risk factors that are associated with subsequent refractory epilepsy.

Diagnostic evaluation in patients with intractable epilepsy and normal findings on MRI: a decision analysis and cost-effectiveness study

BACKGROUND AND PURPOSE

Patients with focal intractable epilepsy and normal MR imaging findings frequently undergo further diagnostic tests to localize the epileptogenic zone. The aim of this study was to determine the cost-effective diagnostic strategy that will identify the epileptogenic zone in patients with suspected focal intractable epilepsy and normal MR imaging findings by using decision analysis.

MATERIALS AND METHODS

A Markov decision model was constructed by using sensitivities and specificities of test strategies, seizure outcomes following surgical and medical treatment, cost, utilities, probabilities, and standardized mortality ratios. We compared 6 diagnostic test strategies: PET, ictal SPECT, and MEG individually; and combinations of PET+SPECT, PET+MEG, and SPECT+MEG. The outcomes measured were health care costs, QALY, and ICER. One-way and probabilistic sensitivity analyses were conducted to adjust for uncertainties in model parameters.

RESULTS

The preferred strategies were PET+MEG and SPECT. The health care cost of the baseline strategy (PET+MEG) was $95,612 with 16.30 QALY gained. SPECT cost $97,479 with 16.45 QALY gained and an ICER of $12,934/QALY gained compared with those in PET+MEG. One-way sensitivity analyses showed that the decisions of the model were sensitive to variations in sensitivity and specificity of the test strategies. Probabilistic sensitivity analysis showed that when the willingness to pay was <$10,000, PET+MEG was the favored strategy, but the favored strategy changed to SPECT when the willingness to pay was >$10,000.

CONCLUSIONS

PET+MEG and SPECT were the preferred strategies in the base case. The choice of test was dependent on the sensitivity and specificity of test strategies and willingness to pay. Further study with a larger sample size is needed to obtain better estimates of sensitivity and specificity of diagnostic tests.

Temporal trends in pre-surgical evaluations and epilepsy surgery in the U.S. from 1998 to 2009

OBJECTIVE

To analyze trends in utilization of pre-surgical evaluations including video-EEG (VEEG) monitoring, intracranial EEG (IEEG) monitoring, and epilepsy surgery from 1998 to 2009 in the U.S.

METHODS

Data from the Nationwide Inpatient Sample were used to identify admissions for pre-surgical evaluations and surgery. Surgical treatment of epilepsy was identified by the presence of primary ICD-9-CM procedure codes 01.52 (hemispherectomy), 01.53 (lobectomy), or 01.59 (other excision of the brain, including amygdalohippocampectomy). We calculated annual rates of pre-surgical evaluations and surgery based on published estimates of prevalence of epilepsy in the U.S. In addition, we examined variations by region and hospital characteristics, and conducted multivariable analysis to detect temporal trends, adjusting for changes in the population. Sensitivity analysis was also conducted using different algorithms to identify the study population and outcomes.

RESULTS

We detected an increase in the rate of hospitalizations related to intractable epilepsy. Similarly, we noted a significant increase in hospitalizations for VEEG monitoring, but not in IEEG monitoring or in surgery. Multivariable analysis and sensitivity analysis confirmed these results. In addition, there was a significant increase in the proportion of pre-surgical evaluations and surgery performed in non-teaching hospitals.

CONCLUSIONS

Despite the increase in VEEG monitoring, the availability of guideline and evidences demonstrating benefits of epilepsy surgery was not associated with a greater employment of surgery over time. Nevertheless, access to pre-surgical evaluations and epilepsy surgery is no longer limited to large medical centers.

Incidence and associations of poststroke epilepsy: the prospective South London Stroke Register

BACKGROUND AND PURPOSE

To describe the epidemiology and associations of poststroke epilepsy (PSE) because there is limited evidence to inform clinicians and guide future research.

METHODS

Data were collected from the population-based South London Stroke Register of first strokes in a multiethnic inner-city population with a maximum follow-up of 12 years. Self-completed forms and interviews notified study organizers of epilepsy diagnosis. Kaplan-Meier methods and Cox models were used to assess associations with sociodemographic factors, clinical features, stroke subtype, and severity markers.

RESULTS

Three thousand three-hundred ten patients with no history of epilepsy presented with first stroke between 1995 and 2007, with a mean follow-up of 3.8 years. Two-hundred thirteen subjects (6.4%) had development of PSE. PSE incidence at 3 months and 1, 5, and 10 years were estimated at 1.5%, 3.5%, 9.0%, and 12.4%, respectively. Sex, ethnicity, and socioeconomic status were not associations, but markers of cortical location, including dysphasia, visual neglect, and field defect, along with stroke severity indices at presentation, including low Glasgow Coma Scale, incontinence, or poor function on Barthel Index, were associated with PSE on univariate analysis. Young age was independently associated with PSE, affecting 10.7% of patients aged <65 years and 1.6% >85 years (P≤0.001) on 10-year estimates. Independent predictors of PSE also included visual neglect, dysphasia, and stroke subtype, particularly total anterior circulation infarcts. Dysarthria was associated with reduced incidence.

CONCLUSIONS

PSE is common, with risk continuing to increase outside the acute phase. Young age, cortical location, larger lesions, and hemorrhagic lesions are independent predictors.

Perfusion network shift during seizures in medial temporal lobe epilepsy

Background

Medial temporal lobe epilepsy (MTLE) is associated with limbic atrophy involving the hippocampus, peri-hippocampal and extra-temporal structures. While MTLE is related to static structural limbic compromise, it is unknown whether the limbic system undergoes dynamic regional perfusion network alterations during seizures. In this study, we aimed to investigate state specific (i.e. ictal versus interictal) perfusional limbic networks in patients with MTLE.

Methods

We studied clinical information and single photon emission computed tomography (SPECT) images obtained with intravenous infusion of the radioactive tracer Technetium- Tc 99 m Hexamethylpropyleneamine Oxime (Tc-99 m HMPAO) during ictal and interictal state confirmed by video-electroencephalography (VEEG) in 20 patients with unilateral MTLE (12 left and 8 right MTLE). Pair-wise voxel-based analyses were used to define global changes in tracer between states. Regional tracer uptake was calculated and state specific adjacency matrices were constructed based on regional correlation of uptake across subjects. Graph theoretical measures were applied to investigate global and regional state specific network reconfigurations.

Results

A significant increase in tracer uptake was observed during the ictal state in the medial temporal region, cerebellum, thalamus, insula and putamen. From network analyses, we observed a relative decreased correlation between the epileptogenic temporal region and remaining cortex during the interictal state, followed by a surge of cross-correlated perfusion in epileptogenic temporal-limbic structures during a seizure, corresponding to local network integration.

Conclusions

These results suggest that MTLE is associated with a state specific perfusion and possibly functional organization consisting of a surge of limbic cross-correlated tracer uptake during a seizure, with a relative disconnection of the epileptogenic temporal lobe in the interictal period. This pattern of state specific shift in metabolic networks in MTLE may improve the understanding of epileptogenesis and neuropsychological impairments associated with MTLE.

Is reoperation an option for patients with temporal lobe epilepsy after failure of surgery?

PURPOSE

Epilepsy surgery is the most efficacious therapeutic modality for patients with medically refractory focal epilepsies, but surgical failures remain a challenge to the epilepsy treatment team. The aim of present study was to evaluate the postoperative outcome of patients who underwent reoperation after a failed epilepsy surgery on the temporal lobe.

METHODS

We systematically analyzed the results of comprehensive preoperative evaluations before the first surgery, and before and after reoperation in 17 patients with drug resistant temporal lobe epilepsies.

RESULTS

Overall, 13 of 17 patients (76.5%) improved after reoperation: five patients (29.4%) were completely seizure free after reoperation (median duration 60months, range 12-72); six patients (35.3%) were seizure free at least 12month before observation points (median duration 120.5months, range 35-155) and two patients (11.8%) had a decrease in seizure frequency. Four patients (23.5%) remained unchanged with respect to seizure frequency and severity. There was no correlation between the improvement in seizure outcome after reoperation and other clinical data except of the history of traumatic brain injury (TBI). The patients who had no history of TBI improved after reoperation, compared to patients with TBI (p=0.044). The postoperative seizure outcome of patients with incongruent Video-EEG results before the first surgery (p=0.116) and before reoperation (p=0.622) was not poorer compared to patients with congruent Video-EEG results.

CONCLUSIONS

Reoperation can considerably improve the operative outcome of the first failed epilepsy surgery in patients with drug resistant temporal lobe epilepsies. Epilepsy centres should be encouraged to report the results of failed epilepsy surgeries.

A decade of experience with deep brain stimulation for patients with refractory medial temporal lobe epilepsy

In this study, we present long-term results from patients with medial temporal lobe (MTL) epilepsy treated with deep brain stimulation (DBS). Since 2001, 11 patients (8M) with refractory MTL epilepsy underwent MTL DBS. When unilateral DBS failed to decrease seizures by > 90%, a switch to bilateral MTL DBS was proposed. After a mean follow-up of 8.5 years (range: 67-120 months), 6/11 patients had a ≥ 90% seizure frequency reduction with 3/6 seizure-free for > 3 years; three patients had a 40%-70% reduction and two had a < 30% reduction. In 3/5 patients switching to bilateral DBS further improved outcome. Uni- or bilateral MTL DBS did not affect neuropsychological functioning. This open study with an extended long-term follow-up demonstrates maintained efficacy of DBS for MTL epilepsy. In more than half of the patients, a seizure frequency reduction of at least 90% was reached. Bilateral MTL DBS may herald superior efficacy in unilateral MTL epilepsy.

Health plan paid cost of epilepsy in 2009 in the U.S

Our objectives were to estimate the health plan paid cost of epilepsy and to show major cost driver(s) of these costs. The health insurance claims and membership data from six U.S. health plans were analyzed. To prepare two comparison groups, individuals with epilepsy (n=5810) were match-paired with individuals without epilepsy (n=5810) using propensity scores derived from logistic regression using gender, age group, health plan product, and length of enrollment in the health plans. Total health plan paid cost per member per year (PMPY) was $11,232 for the epilepsy group and $3026 for the controls (p<0.001). The estimated cost PMPY for treatment of epilepsy was $8206. Relative distribution (%) of health plan paid costs ($) by cost driver category based on place of service (POS) indicated that the treatment of epilepsy places a larger cost burden in inpatient POS than in outpatient hospital or MD office POS compared to controls.

Relationship between hospital surgical volume, lobectomy rates, and adverse perioperative events at US epilepsy centers

OBJECT

Epilepsy surgery remains significantly underutilized. The authors recently reported that the number of lobectomies for localized intractable epilepsy in the US has not changed despite the implementation of clear evidence-based guidelines 10 years ago supporting early referral for surgery. To better understand why epilepsy surgery continues to be underused, the authors' objective was to carefully examine hospital-related factors related to the following: 1) where patients are being admitted for the evaluation of epilepsy, 2) rates of utilization for surgery across hospitals, and 3) perioperative morbidity between hospitals with low versus high volumes of epilepsy surgery.

METHODS

The authors performed a population-based cohort study of US hospitals between 1990 and 2008 using the Nationwide Inpatient Sample (NIS), stratifying epilepsy surgery rates and trends as well as perioperative morbidity rates by hospital surgical volume.

RESULTS

The number of lobectomies for epilepsy performed at high-volume centers (> 15 lobectomies/year) significantly decreased between 1990 and 2008 (F = 20.4, p < 0.001), while significantly more procedures were performed at middle-volume hospitals (5-15 lobectomies/year) over time (F = 16.1, p < 0.001). No time trend was observed for hospitals performing fewer than 5 procedures per year. However, patients admitted to high-volume centers were significantly more likely to receive lobectomy than those at low-volume hospitals (relative risk 1.05, 95% CI 1.03-1.08, p < 0.001). Also, the incidence of perioperative adverse events was significantly higher at low-volume hospitals (12.9%) than at high-volume centers (6.1%) (relative risk 1.08, 95% CI 1.03-1.07, p < 0.001).

CONCLUSIONS

Hospital volume is an important predictor of epilepsy surgery utilization and perioperative morbidity. Patients with medically refractory epilepsy should be referred to a comprehensive epilepsy treatment center for surgical evaluation by an experienced clinical team.

Evidence that temporal lobe is a default area in absence epilepsy

Correctly classifying seizures is essential for appropriate epilepsy management. Focal and generalized epilepsy rarely occur independently in the same patient. Cases of focal ictal evolution during seizures that are generalized in onset have been reported though these have included a small heterogeneous series of patients with generalized epilepsy and features on the EEG. We wish to report two patients with absence epilepsy that were noted on video-EEG monitoring to manifest a focal temporal electroclinical transformation from a typical absence seizure. Defining the electroclinical spectrum of absence seizures could add to our understanding of the selective cortical and subcortical networks that are involved in patients with "prototypic" generalized and focal seizures.

Impact of corticosterone treatment on spontaneous seizure frequency and epileptiform activity in mice with chronic epilepsy

Stress is the most commonly reported precipitating factor for seizures in patients with epilepsy. Despite compelling anecdotal evidence for stress-induced seizures, animal models of the phenomena are sparse and possible mechanisms are unclear. Here, we tested the hypothesis that increased levels of the stress-associated hormone corticosterone (CORT) would increase epileptiform activity and spontaneous seizure frequency in mice rendered epileptic following pilocarpine-induced status epilepticus. We monitored video-EEG activity in pilocarpine-treated mice 24/7 for a period of four or more weeks, during which animals were serially treated with CORT or vehicle. CORT increased the frequency and duration of epileptiform events within the first 24 hours of treatment, and this effect persisted for up to two weeks following termination of CORT injections. Interestingly, vehicle injection produced a transient spike in CORT levels – presumably due to the stress of injection – and a modest but significant increase in epileptiform activity. Neither CORT nor vehicle treatment significantly altered seizure frequency; although a small subset of animals did appear responsive. Taken together, our findings indicate that treatment of epileptic animals with exogenous CORT designed to mimic chronic stress can induce a persistent increase in interictal epileptiform activity.

Inferring evoked brain connectivity through adaptive perturbation

Inference of functional networks-representing the statistical associations between time series recorded from multiple sensors-has found important applications in neuroscience. However, networksexhibiting time-locked activity between physically independent elements can bias functional connectivity estimates employing passive measurements. Here, a perturbative and adaptive method of inferring network connectivity based on measurement and stimulation-so called "evoked network connectivity" is introduced. This procedure, employing a recursive Bayesian update scheme, allows principled network stimulation given a current network estimate inferred from all previous stimulations and recordings. The method decouples stimulus and detector design from network inference and can be suitably applied to a wide range of clinical and basic neuroscience related problems. The proposed method demonstrates improved accuracy compared to network inference based on passive observation of node dynamics and an increased rate of convergence relative to network estimation employing a naïve stimulation strategy.

Predictive model for refractoriness in temporal lobe epilepsy based on clinical and diagnostic test data

INTRODUCTION

Temporal Lobe Epilepsy (TLE) is frequently resistant to drug treatment, but a high percentage of these patients can be free of seizures after epilepsy surgery. Delay in the surgical decision has been related to quality of life impairment, social and work limitations, and increased mortality risk. A predictive model for refractoriness based on clinical and diagnostic factors may allow its earlier detection and a shorter delay before surgery.

MATERIAL AND METHODS

A case-control study was conducted in TLE patients over 16 years old. The dependent variable was resistance to medical treatment according to ILAE 2010 criteria. Independent variables were clinical, semiological, therapeutic, neurophysiological, radiological, and neuropsychological variables. A multivariate study was conducted to identify the variables associated with refractoriness, calculating the positive and negative predictive values and positive likelihood ratios of these variables individually and in combination. These data were used to construct a refractoriness predictive model.

RESULTS

ILAE refractoriness criteria were met by 83 patients (50.9%). In the multivariate analysis, refractoriness was significantly associated with one semiological variable, one neuroradiological variable, one neurophysiological variable, and two therapeutic variables but not with neuropsychological test outcomes. These significant variables were used to construct a predictive model.

CONCLUSION

Assessment of semiological, neurophysiological, and neuroradiological data can serve to stratify the risk of refractory epilepsy in TLE patients.

AAN Epilepsy Quality Measures in clinical practice: a survey of neurologists

Epilepsy Quality Measures (EQM) were developed by the American Academy of Neurology (AAN) to convey standardization and eliminate gaps and variations in the delivery of epilepsy care (Fountain et al., 2011 [1]). The aim of this study was to identify adherence to these measures and other emerging practice standards in epilepsy care. A 15-item survey was mailed to neurologists in Michigan, USA, inquiring about their practice patterns in relation to EQM. One hundred thirteen of the 792 surveyed Michigan Neurologists responded (14%). The majority (83% to 94%) addressed seizure type and frequency, reviewed EEG and MRI, and provided pregnancy counseling to women of childbearing potential. Our survey identified gaps in practice patterns such as counseling about antiepileptic drug (AED) side effects and knowledge about referral for surgical therapy of intractable epilepsy. Statistical significance in the responses on the AAN EQM was noted in relation to number of years in practice, number of epilepsy patients seen, and additional fellowship training in epilepsy. Practice patterns assessment in relation to other comorbidities revealed that although bone health and sudden unexplained death in epilepsy are addressed mainly in patients at risk, depression is infrequently discussed. The findings in this study indicate that additional educational efforts are needed to increase awareness and to improve quality of epilepsy care at various points of health care delivery.

Neocortical temporal lobe epilepsy

Complex partial seizures (CPSs) can present with various semiologies, while mesial temporal lobe epilepsy (mTLE) is a well-recognized cause of CPS, neocortical temporal lobe epilepsy (nTLE) albeit being less common is increasingly recognized as separate disease entity. Differentiating the two remains a challenge for epileptologists as many symptoms overlap due to reciprocal connections between the neocortical and the mesial temporal regions. Various studies have attempted to correctly localize the seizure focus in nTLE as patients with this disorder may benefit from surgery. While earlier work predicted poor outcomes in this population, recent work challenges those ideas yielding good outcomes in part due to better localization using improved anatomical and functional techniques. This paper provides a comprehensive review of the diagnostic workup, particularly the application of recent advances in electroencephalography and functional brain imaging, in neocortical temporal lobe epilepsy.

Epilepsy surgery utilization: who, when, where, and why?

PURPOSE OF REVIEW

Using the most recent evidence, we provide an update on epilepsy surgery, focusing on its effectiveness, reasons for underutilization, considerations of candidacy and timing for referral for epilepsy surgery evaluation.

RECENT FINDINGS

The course of illness of epilepsy is being characterized. Well conducted studies describe the patterns of seizure remission and relapse with medical therapy and also in response to epilepsy surgery. Epilepsy surgery is highly effective in selected patients with drug-resistant epilepsy (DRE). The risk-benefit of epilepsy surgery is well known and consistent around the world. However, epilepsy surgery remains underutilized. A randomized controlled trial and Clinical Practice Guidelines (CPGs) supporting epilepsy surgery have had no discernible impact on referral rates for epilepsy surgery evaluation. Criteria and guidelines are being developed for identifying patients who need to be referred for epilepsy surgery evaluation. Quality indicators for epilepsy care now also include the need to consider surgical candidacy every 3 years in DRE. New developments in imaging and neurophysiology promise to help clinicians identify and treat patients more accurately.

SUMMARY

Surgery is effective but underused. Comprehensive interventions to translate evidence to practice in epilepsy surgery are urgently needed.

Acceptance of epilepsy surgery among adults with epilepsy--what do patients think?

Physician inertia is usually blamed for the underutilization of epilepsy surgery (ES) at the cost of increased patient disability and risk of mortality. Investigations on selected groups of patients with intractable TLE and minorities suggested that patient beliefs may also limit access to ES. To assess acceptance of ES among "mainstream" patients, we distributed an ad hoc questionnaire to 228 adults attending epilepsy clinics and found widespread fears and misconceptions leading to unfavorable perception of ES, irrespective of diagnosis, seizure type, and degree of intractability. Moreover, while a group firmly rejected ES, the majority became more favorable when given further information about modality, rationale, and expected outcome of ES. Attitude changes correlated with patient's social profile. Neurologists are responsible for providing all pertinent information to potential surgical candidates as soon as indicated. Therefore, an untimely or inadequate intervention of the treating physician constitutes an additional barrier to optimal utilization of ES.

[Evaluation of a pathway of epilepsy surgery in a polyvalent video-EEG center: retrospective analysis of a series of 295 patients]

BACKGROUND AND PURPOSE

The supply for diagnosis and treatment is inadequate in France for epileptic patients eligible for surgery. Our institution includes a Video-electroencephalography (v-EEG) unit and a general neurosurgery department. Our objective was to evaluate the efficacy and morbidity of the surgery performed in a center non-dedicated to epilepsy surgery.

METHODS

We conducted a retrospective study of a cohort of 295 patients explored with long lasting v-EEG from 1991 to 2008 in Tours in which we evaluated the efficacy and morbidity of the surgery distinguishing between hippocampal sclerosis and other epileptogenic lesions.

RESULTS

Phase I directly led to surgery in 31 cases. Of them were 19 hippocampal sclerosis were operated with no surgical morbidity, and 12 other epileptogenic lesions operated with a comorbidity in two patients. Results of surgery were similar to larger studies, with 80% of patients Engel's Class I. Best results were observed in the hippocampal sclerosis group: 94.7 Class I (IA: 84%), versus 58% Class I (IA: 33%) for other etiologies.

CONCLUSION

Despite the small number of operated patients, the surgical treatment keeps its efficiency without adding morbidity. v-EEG centers combined with non-specialists neurosurgical teams can contribute to improve care without reducing their quality.

Hippocampal stimulation in the treatment of epilepsy

Neuromodulation is one of the fastest growing fields in neurosurgery, as reflected by the growing interest in the use of electrical brain stimulation (EBS) to treat drug-resistant epilepsy, pain, and movement disorders. Hippocampal stimulation should be regarded as an experimental therapy for epilepsy, and patients considered for this intervention should do so in the context of a well-designed randomized controlled trial. Only well-conducted, blinded, randomized trials, followed by long-term systematic observation will yield a clear picture of the effect of this promising therapy, and will help guide its future use. This article provides a critical review of the best available evidence on hippocampal stimulation for epilepsy.

Electroencephalography in mesial temporal lobe epilepsy: a review

Electroencephalography (EEG) has an important role in the diagnosis and classification of epilepsy. It can provide information for predicting the response to antiseizure drugs and to identify the surgically remediable epilepsies. In temporal lobe epilepsy (TLE) seizures could originate in the medial or lateral neocortical temporal region, and many of these patients are refractory to medical treatment. However, majority of patients have had excellent results after surgery and this often relies on the EEG and magnetic resonance imaging (MRI) data in presurgical evaluation. If the scalp EEG data is insufficient or discordant, invasive EEG recording with placement of intracranial electrodes could identify the seizure focus prior to surgery. This paper highlights the general information regarding the use of EEG in epilepsy, EEG patterns resembling epileptiform discharges, and the interictal, ictal and postictal findings in mesial temporal lobe epilepsy using scalp and intracranial recordings prior to surgery. The utility of the automated seizure detection and computerized mathematical models for increasing yield of non-invasive localization is discussed. This paper also describes the sensitivity, specificity, and predictive value of EEG for seizure recurrence after withdrawal of medications following seizure freedom with medical and surgical therapy.

Antiepileptic drug selection for partial-onset seizures

OPINION STATEMENT

Effective treatment of seizures resulting from epilepsy relies on several basic principles, regardless of which drug or treatment is selected. Treatment starts with a confident diagnosis that the symptoms are, indeed, seizure. The seizure type should be classified as focal in onset or primary generalized, and there should be a relentless search for the etiology. Many antiepileptic drugs (AEDs) are available to treat partial-onset seizures. Given that the efficacy of AEDs is comparable, selection of the appropriate drug is mostly determined by whether any comorbidities are present, such as migraine, obesity, depression, or chronic pain. In the absence of comorbidities, it depends on the side effect profile, cost, and convenience. Most AEDs, with a few exceptions, must be increased to a maximum tolerated dose before a second drug should be added. Most patients can become seizure free or adequately controlled if continued interventions are considered at each encounter until patients are seizure free.

Delayed complication after Gamma Knife surgery for mesial temporal lobe epilepsy

Object

Despite the controversy over the clinical significance of Gamma Knife surgery (GKS) for refractory mesial temporal lobe epilepsy (MTLE), the modality has attracted attention because it is less invasive than resection. The authors report long-term outcomes for 7 patients, focusing in particular on the long-term complications.

Methods

Between 1996 and 1999, 7 patients with MTLE underwent GKS. The 50% marginal dose covering the medial temporal structures was 18 Gy in 2 patients and 25 Gy in the remaining 5 patients.

Results

High-dose treatment abolished the seizures in 2 patients and significantly reduced them in 2 others. One patient in this group was lost to follow-up. However, 2 patients presented with symptomatic radiation necrosis (SRN) necessitating resection after 5 and 10 years. One patient who did not need necrotomy continued to show radiation necrosis on MRI after 10 years. One patient died of drowning while swimming in the sea 1 year after GKS, before seizures had disappeared completely.

Conclusions

High-dose treatment resulted in sufficient seizure control but carried a significant risk of SRN after several years. Excessive target volume was considered as a reason for delayed necrosis. Drawbacks such as a delay in seizure control and the risk of SRN should be considered when the clinical significance of this treatment is evaluated.

Epilepsy surgery trends in the United States, 1990-2008

OBJECTIVE

To examine national time trends of resective surgery for the treatment of medically refractory epilepsy before and after Class I evidence demonstrating its efficacy and subsequent practice guidelines recommending early surgical evaluation.

METHODS

We performed a population-based cohort study with time trends of patients admitted to US hospitals for medically refractory focal epilepsy between 1990 and 2008 who did or did not undergo lobectomy, as reported in the Nationwide Inpatient Sample.

RESULTS

Weighted data revealed 112,026 hospitalizations for medically refractory focal epilepsy and 6,653 resective surgeries (lobectomies and partial lobectomies) from 1990 to 2008. A trend of increasing hospitalizations over time was not accompanied by an increase in surgeries, producing an overall trend of decreasing surgery rates (F = 13.6, p < 0.01). Factors associated with this trend included a decrease in epilepsy hospitalizations at the highest-volume epilepsy centers, and increased hospitalizations to lower-volume hospitals that were found to be less likely to perform surgery. White patients were more likely to have surgery than racial minorities (relative risk [RR], 1.13; 95% confidence interval [CI], 1.10-1.17), and privately insured individuals were more likely to receive lobectomy than those with Medicaid or Medicare (RR, 1.28; 95% CI, 1.25-1.30).

CONCLUSION

Despite Class I evidence and subsequent practice guidelines, the utilization of lobectomy has not increased from 1990 to 2008. Surgery continues to be heavily underutilized as a treatment for epilepsy, with significant disparities by race and insurance coverage. Patients who are medically refractory after failing 2 antiepileptic medications should be referred to a comprehensive epilepsy center for surgical evaluation.

Early surgical therapy for drug-resistant temporal lobe epilepsy: a randomized trial

CONTEXT

Despite reported success, surgery for pharmacoresistant seizures is often seen as a last resort. Patients are typically referred for surgery after 20 years of seizures, often too late to avoid significant disability and premature death.

OBJECTIVE

We sought to determine whether surgery soon after failure of 2 antiepileptic drug (AED) trials is superior to continued medical management in controlling seizures and improving quality of life (QOL).

DESIGN, SETTING, AND PARTICIPANTS

The Early Randomized Surgical Epilepsy Trial (ERSET) is a multicenter, controlled, parallel-group clinical trial performed at 16 US epilepsy surgery centers. The 38 participants (18 men and 20 women; aged ≥12 years) had mesial temporal lobe epilepsy (MTLE) and disabling seizues for no more than 2 consecutive years following adequate trials of 2 brand-name AEDs. Eligibility for anteromesial temporal resection (AMTR) was based on a standardized presurgical evaluation protocol. Participants were randomized to continued AED treatment or AMTR 2003-2007, and observed for 2 years. Planned enrollment was 200, but the trial was halted prematurely due to slow accrual.

INTERVENTION

Receipt of continued AED treatment (n = 23) or a standardized AMTR plus AED treatment (n = 15). In the medical group, 7 participants underwent AMTR prior to the end of follow-up and 1 participant in the surgical group never received surgery.

MAIN OUTCOME MEASURES

The primary outcome variable was freedom from disabling seizures during year 2 of follow-up. Secondary outcome variables were health-related QOL (measured primarily by the 2-year change in the Quality of Life in Epilepsy 89 [QOLIE-89] overall T-score), cognitive function, and social adaptation.

RESULTS

Zero of 23 participants in the medical group and 11 of 15 in the surgical group were seizure free during year 2 of follow-up (odds ratio = ∞; 95% CI, 11.8 to ∞; P < .001). In an intention-to-treat analysis, the mean improvement in QOLIE-89 overall T-score was higher in the surgical group than in the medical group but this difference was not statistically significant (12.6 vs 4.0 points; treatment effect = 8.5; 95% CI, -1.0 to 18.1; P = .08). When data obtained after surgery from participants in the medical group were excluded, the effect of surgery on QOL was significant (12.8 vs 2.8 points; treatment effect = 9.9; 95% CI, 2.2 to 17.7; P = .01). Memory decline (assessed using the Rey Auditory Verbal Learning Test) occurred in 4 participants (36%) after surgery, consistent with rates seen in the literature; but the sample was too small to permit definitive conclusions about treatment group differences in cognitive outcomes. Adverse events included a transient neurologic deficit attributed to a magnetic resonance imaging-identified postoperative stroke in a participant who had surgery and 3 cases of status epilepticus in the medical group.

CONCLUSIONS

Among patients with newly intractable disabling MTLE, resective surgery plus AED treatment resulted in a lower probability of seizures during year 2 of follow-up than continued AED treatment alone. Given the premature termination of the trial, the results should be interpreted with appropriate caution.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00040326.

Inequities in access to pediatric epilepsy surgery: a bioethical framework

Epilepsy is a common childhood condition associated with a considerable medical and psychosocial burden. Children in whom medical treatment fails to reduce seizure burden represent an especially vulnerable patient population because prolonged, uncontrolled seizures are associated with poor developmental and neurocognitive outcomes. Surgical treatment in the form of cortical resection, functional disconnection, or neuromodulation may alleviate or significantly reduce the disease burden for a subset of these patients. However, there remains a dichotomy between the perceived benefits of surgery and the implementation of surgical strategies in the management of medically intractable epilepsy. The current paper presents an analysis of the bioethical implications of existing inequities in access to pediatric epilepsy surgery that result from inconsistent referral practices and discrepant evaluation techniques. The authors provide a basic bioethical framework composed of 5 primary expectations to inform public, institutional, and personal policies toward the provision of epilepsy surgery to afflicted children.

Determining surgical candidacy in temporal lobe epilepsy

Temporal lobe epilepsy (TLE) is the most common form of adult epilepsy that is amenable to surgical treatment. In the carefully selected patient, excellent seizure outcome can be achieved with minimal or no side effects from surgery. This may result in improved psychosocial functioning, achieving higher education, and maintaining or gaining employment. The objective of this paper is to discuss the surgical selection process of a patient with TLE. We define what constitutes a patient that has medically refractory TLE, describe the typical history and physical examination, and distinguish between mesial TLE and neocortical TLE. We then review the role of routine (ambulatory/sleep-deprived electroencephalography (EEG), video EEG, magnetic resonance imaging (MRI), neuropsychological testing, and Wada testing) and ancillary preoperative testing (positron emission tomography, single-photon emission computed tomography (SPECT), subtraction ictal SPECT correlated to MRI (SISCOM), magnetoencephalography, magnetic resonance spectroscopy, and functional MRI) in selecting surgical candidates. We describe the surgical options for resective epilepsy surgery in TLE and its commonly associated risks while highlighting some of the controversies. Lastly, we present teaching cases to illustrate the presurgical workup of patients with medically refractory TLE.

Biomarkers in epilepsy: introduction

Epilepsy is the most common serious primary disease of the brain, accounting for 1% of the global burden of disease. Diagnosis and treatment suffer from a lack of reliable biomarkers for either epileptogenicity, the presence and severity of an epilepsy condition, or epileptogenesis, the development and progression of an epilepsy condition. The identification of reliable biomarkers would greatly facilitate differential diagnosis, eliminate the current trial-and-error approach to pharmacotherapy, facilitate presurgical evaluation, and greatly improve the cost-effectiveness of drug discovery and clinical trials of agents designed to treat, prevent and cure epilepsy. Identification of reliable biomarkers of epileptogenicity and epileptogenesis for research and clinical applications is a high-priority goal for the epilepsy community. Recent advances in electrophysiology, neuroimaging, molecular biology and genetics promise to reveal clinically useful biomarkers for epilepsy in the near future.