Long-term seizure outcome of surgery versus no surgery for drug-resistant partial epilepsy: A review of controlled studies

Lifestyle Behavioral Interventions and Health-Related Outcomes Among People with Epilepsy: A Review of Randomized Controlled Trials

OBJECTIVE

To gather and assess current literature on the prevalence and efficacy of lifestyle behavioral interventions (sleep, nutrition, physical activity) for health outcomes, including QOL, psychological well-being, behavioral changes, and seizure frequency, among PWE.

DATA SOURCE

A review was conducted of English-language articles identified from PubMed, Scopus, and Embase between January 2013 to January 2023.

STUDY INCLUSION AND EXCLUSION CRITERIA

Inclusion criteria were randomized controlled trials (RCT) with human subjects diagnosed with epilepsy who participated in a lifestyle behavioral intervention.

DATA EXTRACTION

Two researchers independently completed the title, abstract, and full-text reviews. Information extracted includes study population, duration, type of intervention, findings, and outcomes.

DATA SYNTHESIS

Data was narratively synthesized to show level of evidence and degree of consistency in findings. Results: 4001 studies identified, 66 full texts reviewed, and 24 included. A majority (n = 16) of studies utilized diet specific RCTs, and some focused on physical activity (n = 7) and sleep (n = 1). Diet-specific RCTs (eg, ketogenic, Modified Atkins) reported reduced seizure frequency with adverse effects, such as gastrointestinal complications. Physical activity-based interventions found that maintained levels of exercise improved QOL and psychological well-being. However, physical activity and diet-based interventions did not have lasting effects after study conclusion. Only the behavioral sleep intervention reported that sleep quality improved significantly and was maintained post-intervention.

CONCLUSION

Future research is needed to establish the relationship between lifestyle behavioral interventions on QOL and other health outcomes (eg, seizure frequency).

Combining OPM and lesion mapping data for epilepsy surgery planning: a simulation study

When planning for epilepsy surgery, multiple potential sites for resection may be identified through anatomical imaging. Magnetoencephalography (MEG) using optically pumped sensors (OP-MEG) is a non-invasive functional neuroimaging technique which could be used to help identify the epileptogenic zone from these candidate regions. Here we test the utility of a-priori information from anatomical imaging for differentiating potential lesion sites with OP-MEG. We investigate a number of scenarios: whether to use rigid or flexible sensor arrays, with or without a-priori source information and with or without source modelling errors. We simulated OP-MEG recordings for 1309 potential lesion sites identified from anatomical images in the Multi-centre Epilepsy Lesion Detection (MELD) project. To localise the simulated data, we used three source inversion schemes: unconstrained, prior source locations at centre of the candidate sites, and prior source locations within a volume around the lesion location. We found that prior knowledge of the candidate lesion zones made the inversion robust to errors in sensor gain, orientation and even location. When the reconstruction was too highly restricted and the source assumptions were inaccurate, the utility of this a-priori information was undermined. Overall, we found that constraining the reconstruction to the region including and around the participant's potential lesion sites provided the best compromise of robustness against modelling or measurement error.

[18F]FDG PET metabolic patterns in mesial temporal lobe epilepsy with different pathological types

OBJECTIVES

To investigate [18F]FDG PET patterns of mesial temporal lobe epilepsy (MTLE) patients with distinct pathologic types and provide possible guidance for predicting long-term prognoses of patients undergoing epilepsy surgery.

METHODS

This was a retrospective review of MTLE patients who underwent anterior temporal lobectomy between 2016 and 2021. Patients were classified as having chronic inflammation and gliosis (gliosis, n = 44), hippocampal sclerosis (HS, n = 43), or focal cortical dysplasia plus HS (FCD-HS, n = 13) based on the postoperative pathological diagnosis. Metabolic patterns and the severity of metabolic abnormalities were investigated among MTLE patients and healthy controls (HCs). The standardized uptake value (SUV), SUV ratio (SUVr), and asymmetry index (AI) of regions of interest were applied to evaluate the severity of metabolic abnormalities. Imaging processing was performed with statistical parametric mapping (SPM12).

RESULTS

With a mean follow-up of 2.8 years, the seizure freedom (Engel class IA) rates of gliosis, HS, and FCD-HS were 54.55%, 62.79%, and 69.23%, respectively. The patients in the gliosis group presented a metabolic pattern with a larger involvement of extratemporal areas, including the ipsilateral insula. SUV, SUVr, and AI in ROIs were decreased for patients in all three MTLE groups compared with those of HCs, but the differences among all three MTLE groups were not significant.

CONCLUSIONS

MTLE patients with isolated gliosis had the worst prognosis and hypometabolism in the insula, but the degree of metabolic decrease did not differ from the other two groups. Hypometabolic regions should be prioritized for [18F]FDG PET presurgical evaluation rather than [18F]FDG uptake values.

CLINICAL RELEVANCE STATEMENT

This study proposes guidance for optimizing the operation scheme in patients with refractory MTLE and emphasizes the potential of molecular neuroimaging with PET using selected tracers to predict the postsurgical histology of patients with refractory MTLE epilepsy.

KEY POINTS

• MTLE patients with gliosis had poor surgical outcomes and showed a distinct pattern of decreased metabolism in the ipsilateral insula. • In the preoperative assessment of MTLE, it is recommended to prioritize the evaluation of glucose hypometabolism areas over [18F]FDG uptake values. • The degree of glucose hypometabolism in the epileptogenic focus was not associated with the surgical outcomes of MTLE.

Long-Term Seizure Freedom, Resolution of Epilepsy and Perceived Life Changes in Drug Resistant Temporal Lobe Epilepsy With Hippocampal Sclerosis: Comparison of Surgical Versus Medical Management

BACKGROUND

Outcome of temporal lobe epilepsy associated with hippocampal sclerosis (TLE-HS) has rarely been evaluated exclusively.

OBJECTIVE

To compare long-term seizure freedom, resolution of epilepsy, and perceived life changes in patients with drug-resistant TLE-HS who underwent surgery vs those who opted for best medical management.

METHODS

In this retrospective longitudinal study, 346 patients with TLE-HS who underwent surgery were compared with 325 who received best medical management. Predictors for long-term remission, resolution of epilepsy, and seizure recurrence were analyzed.

RESULTS

The duration of follow-up ranged from 3-18 (mean 12.61) years. The average age of study population was 28.54 ± 12.27 years with 321 (47.8%) women. Age at onset of epilepsy (11.84 ± 8.48 vs 16.29 ± 11.88; P ≤ .001) was lower, and duration of epilepsy (15.65 ± 9.33 vs 12.97 ± 11.44; P < .001) was higher in the surgery group. Seizure freedom at 3 (81.8 vs 19.0%; P < .001), 5 (73% vs 16.1%; P < .001), and 10 years (78.3% vs 18.5; P < .001) and resolution of epilepsy (30.5% vs 0.6%; P < .001) was higher in the surgery group. The overall perceived life changes score was higher in the surgery group (80.96 ± 25.47 vs 66.24 ± 28.13; P < .001). At long-term follow-up (≥10 years), the presence of an aura was the strongest predictor for resolution of epilepsy (β: 2.29 [95% CI; 1.06-4.93]; P = .035), whereas acute postoperative seizures (APOS) (β: 6.06 [95% CI 1.57-23.42]; P < .001) and an abnormal postoperative EEG (β: 0.222 [95% CI 0.100-0.491]; P < .001) were predictors of persistent seizures. Seizure freedom both at 3 and 5 years predicted seizure freedom at 10 years.

CONCLUSION

Surgery for drug-resistant TLE-HS was associated with higher rate of long-term seizure-freedom, resolution of epilepsy, and reduction of anti-seizure medications with improvement in perceived life changes compared with best medical management. The presence of an aura was predictor for resolution of epilepsy while APOS and an abnormal postoperative EEG were predictors of persistent seizures.

Adjunctive cenobamate in highly active and ultra-refractory focal epilepsy: A "real-world" retrospective study

OBJECTIVE

Recent clinical trials have shown that cenobamate substantially improves seizure control in focal-onset drug-resistant epilepsy (DRE). However, little is known about cenobamate's performance in highly active (≥20 seizures/month) and ultra-refractory focal epilepsy (≥6 failed epilepsy treatments, including antiseizure medications [ASMs], epilepsy surgery, and vagus nerve stimulation). Here, we studied cenobamate's efficacy and tolerability in a "real-world" severe DRE cohort.

METHODS

We conducted a single-center retrospective analysis of consecutive adults treated with cenobamate between October 2020 and September 2022. All patients received cenobamate through an Early Access Program. Cenobamate retention, seizure outcomes, treatment-emergent adverse events, and adjustments to concomitant ASMs were analyzed.

RESULTS

Fifty-seven patients received cenobamate for at least 3 months (median duration, 11 months). The median cenobamate dose was 250 mg/day (range 75-350 mg). Baseline demographics were consistent with highly active (median seizure frequency, 60/month) and ultra-refractory epilepsy (median previously failed ASMs, nine). Most (87.8%) had prior epilepsy surgery and/or vagus nerve stimulation. Six patients stopped cenobamate due to lack of efficacy and/or adverse events. One patient died from factors unrelated to cenobamate. Among patients who continued cenobamate, three achieved seizure freedom (5.3% of cohort), 24 had a 75%-99% reduction in seizures (42.1% of cohort), and 16 had a 50%-74% reduction (28.1% of cohort). Cenobamate led to abolition of focal to bilateral tonic-clonic seizures in 55.6% (20/36) of patients. Among treatment responders, 67.4% (29/43) were treated with cenobamate doses of ≥250 mg/day. Three-fourths of patients reported at least one side-effect, most commonly fatigue and somnolence. Adverse events most commonly emerged at cenobamate doses of ≥250 mg/day. Side-effects were partially manageable by reducing the overall ASM burden, most often clobazam, eslicarbazepine, and perampanel.

SIGNIFICANCE

Patients with highly active and ultra-refractory focal epilepsy experienced meaningful seizure outcomes on cenobamate. Emergence of adverse events at doses above 250 mg/day may limit the potential for further improvements in seizure control at higher cenobamate doses.

How patients' psycho-social profiles contribute to decision-making in epilepsy surgery: A prospective study

OBJECTIVE

Identifying factors associated with surgical decision-making is important to understand reasons for underutilization of epilepsy surgery. Neurologists' recommendations for surgery and patients' acceptance of these recommendations depend on clinical epilepsy variables, for example, lateralization and localization of seizure onset zones. Moreover, previous research shows associations with demographic factors, for example, age and sex. Here, we investigate the relevance of patients' psycho-social profile for surgical decision-making.

METHODS

We prospectively studied 296 patients from two large German epilepsy centers. Multiple logistic regression analyses were used to investigate variables linked to neurologists' recommendations for and patients' acceptance of surgery or intracranial video-electroencephalographic monitoring. Patients' psycho-social profiles were assessed via self-reports and controlled for various clinical-demographic variables. Model selection was performed using the Akaike information criterion.

RESULTS

As expected, models for neurologists' surgery recommendations primarily revealed clinical factors such as lateralization and localization of the seizure onset zone, load with antiseizure medication (ASM), and site of the epilepsy-center. For this outcome, employment was the only relevant psycho-social aspect (odds ratio [OR] = .38, 95% confidence interval [CI] = .13-1.11). In contrast, three of the five relevant predictors for patients' acceptance were psycho-social. Higher odds were found for those with more subjective ASM adverse events (OR = 1.04, 95% CI = .99-1.00), more subjective seizure severity (OR = 1.12, 95% CI = 1.01-1.24), and lower subjective cognitive impairment (OR = .98, 95% CI = .96-1.00).

SIGNIFICANCE

We demonstrated the relevance of the patients' psycho-social profile for decision-making in epilepsy surgery, particularly for patients' decisions. Thus, in addition to clinical-demographic variables, patients' individual psycho-social characteristics add to the understanding of surgical decision-making. From a clinical perspective, this calls for individually tailored counseling to assist patients in finding the optimal treatment option.

Implantation of Intracranial Electrodes Predicts Worse Outcome in Mesial Temporal Lobe Epilepsy

OBJECTIVE

Anteromesial resection is an effective method for treating seizures arising from the medial temporal lobe, as these cases are often the most straightforward and have the best outcomes. Nevertheless, some patients who go on to have a mesial resection are recommended to have an implantation of electrodes before surgery. Whether the need for such an implant alters the rate of seizure freedom is not well-studied in this particular subgroup of epilepsy patients.

METHODS

We performed a retrospective review of consecutive anteromesial surgeries for medial temporal lobe epilepsy performed between 2005 and 2020. Of a total of 39 patients, 19 required electrode implantation (electrode group) and 20 did not (no-electrode group). The primary outcomes assessed were reduction in seizure frequency and Engel score. Complication rates were also compared.

RESULTS

Postresection seizure frequency reduction was nonsignificantly higher in the no-electrode group (97.0 ± 10.3%) than in the electrode group (88.5 ± 23.7%, P = 0.15). The rate of Engel I outcome was nonsignificantly higher in the no-electrode group (84.2%) than in the electrode group (65.0%, P = 0.17). Major complication rates were nonsignificantly higher in the no-electrode group (15.8 ± 1.9%) than in the electrode group (5.0 ± 1.1%, P = 0.26). Power analysis revealed that 74 patients would need to be included in each group to reach statistical significance.

CONCLUSIONS

Although not statistically significant, our study showed a trend for improved seizure control if a decision was made not to implant electrodes prior to potentially curative anteromesial resection. Engel I outcome in this group reached approximately 85%. A larger multi-instiutional study may be required to reach statistical significance.

Long-term seizure, psychiatric and socioeconomic outcomes after frontal lobe epilepsy surgery

OBJECTIVE

Resective surgery for selected individuals with frontal lobe epilepsy can be effective, although multimodal outcomes are less established than in temporal lobe epilepsy. We describe long-term seizure remission and relapse patterns, psychiatric comorbidity, and socioeconomic outcomes following frontal lobe epilepsy surgery.

METHODS

We reviewed individual data on frontal lobe epilepsy procedures at our center between 1990 and 2020. This included the presurgical evaluation, operative details and annual postoperative seizure and psychiatric outcomes, prospectively recorded in an epilepsy surgery database. Outcome predictors were subjected to multivariable analysis, and rates of seizure freedom were analyzed using Kaplan-Meier methods. We used longitudinal assessment of the Index of Multiple Deprivation to assess change in socioeconomic status over time.

RESULTS

A total of 122 individuals with a median follow-up of seven years were included. Of these, 33 (27 %) had complete seizure freedom following surgery, with a further 13 (11 %) having only auras. Focal MRI abnormality, histopathology (focal cortical dysplasia, cavernoma or dysembryoplastic neuronal epithelial tumor) and fewer anti-seizure medications at the time of surgery were predictive of a favorable outcome; 67 % of those seizure-free for the first 12 months after surgery never experienced a seizure relapse. Thirty-one of 50 who had preoperative psychiatric pathology noticed improved psychiatric symptomatology by two years postoperatively. New psychiatric comorbidity was diagnosed in 15 (13 %). Persistent motor complications occurred in 5 % and dysphasia in 2 %. No significant change in socioeconomic deciles of deprivation was observed after surgery.

SIGNIFICANCE

Favorable long-term seizure, psychiatric and socioeconomic outcomes can be seen following frontal lobe epilepsy surgery. This is a safe and effective treatment that should be offered to suitable individuals early.

Outcome of epilepsy surgery in lesional epilepsy: Experiences from a developing country

BACKGROUND

Our aim was to report the postoperative seizure outcome and associated factors in patients with lesional epilepsy, in a low-income setting.

METHODS

This longitudinal prospective study included patients who underwent epilepsy surgery at Kashani Comprehensive Epilepsy Center between 2014 and 2019. Post-surgical outcomes were reported according to the Engel score, and patients were classified into two groups of seizure free (SF) and not-seizure free (NSF).

RESULTS

A total of 148 adult patients, with a mean age of 30.45 ± 9.23 years were included. The SF outcome was reported in 86.5% of patients and antiepileptic drugs (AEDs) were reduced or discontinued in 45.9%. The mean follow-up duration was 26.7 ± 14.9 months. Temporal lobe lesions (76.3%) and mesial temporal sclerosis (MTS) (56.7%) were the most frequent etiologies. Temporal lesion (Incidence relative risk (IRR): 1.76, 95% CI [1.08-2.87], p = 0.023), prior history of CNS infection (IRR:1.18, 95% CI [1.03-1.35], p = 0.019), use of intra-operative ECoG (IRR:1.73, 95% CI [1.06-2.81], p = 0.028), and absence of IEDs in postoperative EEG (IRR: 1.41, 95% CI [1.18-1.70], p < 0.001) were positive predictors for a favorable outcome.

CONCLUSION

Many patients with drug-resistant lesional epilepsy showed a favorable response to surgery. We believe that resective epilepsy surgery in low-income settings is a major treatment option. The high frequency of patients with drug-resistant epilepsy in developing countries is associated with high rates of morbidity and mortality. Hence, strategies to increase access to epilepsy surgery in these settings are urgently needed.

Single-Institutional Experience of Chronic Intracranial Electroencephalography Based on the Combined Usage of Subdural and Depth Electrodes

Implantation of subdural electrodes on the brain surface is still widely performed as one of the “gold standard methods” for the presurgical evaluation of epilepsy. Stereotactic insertion of depth electrodes to the brain can be added to detect brain activities in deep-seated lesions to which surface electrodes are insensitive. This study tried to clarify the efficacy and limitations of combined implantation of subdural and depth electrodes in intractable epilepsy patients. Fifty-three patients with drug-resistant epilepsy underwent combined implantation of subdural and depth electrodes for long-term intracranial electroencephalography (iEEG) before epilepsy surgery. The detectability of early ictal iEEG change (EIIC) were compared between the subdural and depth electrodes. We also examined clinical factors including resection of MRI lesion and EIIC with seizure freedom. Detectability of EIIC showed no significant difference between subdural and depth electrodes. However, the additional depth electrode was useful for detecting EIIC from apparently deep locations, such as the insula and mesial temporal structures, but not in detecting EIIC in patients with ulegyria (glial scar). Total removal of MRI lesion was associated with seizure freedom. Depth electrodes should be carefully used after consideration of the suspected etiology to avoid injudicious usage.

Unanticipated improvement in seizure control in drug-resistant epilepsy- real world observations

OBJECTIVES

To determine the clinical features and anti-seizure medication (ASM) strategies associated with an unanticipated substantial improvement in seizure control in patients with drug-resistant epilepsy (DRE).

METHODS

This retrospective analysis of patients attending a tertiary care epilepsy clinic between 2008 and 2017 identified all patients with active DRE (at least 1 seizure per month for 6 months, despite treatment with 2 different ASMs). All treatment interventions were recorded from when DRE was first identified to the end of the study. The primary end points were seizure freedom or meaningful reduction in seizure frequency (greater than 75 %) sustained for at least 12 months after a treatment intervention.

RESULTS

Three hundred and twenty-two patients were included in the analysis. Overall, 10 % became seizure free following ASM adjustment and an additional 10 % had a greater than 75 % improvement in seizure control (median follow-up, 4 years). An ASM introduction was ten times more likely than an ASM dose increase to improve seizure control. Combined focal and generalized epilepsy, intellectual disability and prior treatment with more than 5 ASMs were more frequently observed in those with continued pharmacoresistance. ASM responders were more likely to have primary generalized epilepsy. Rational polytherapy (combining ASMs with different mechanisms of action) was almost ubiquitous amongst ASMs responders (95 % taking at least 2 drugs with different mechanistic targets). Of the ASM additions that heralded improved seizure control, 85 % were maintained at submaximal doses.

CONCLUSIONS

This retrospective analysis of a large number of 'real-world' patients provides evidence to persist with ASM trials in DRE. Early rotation of ASMs if a clinical response is not observed at a substantial dose and rational ASM polytherapy may yield better clinical outcomes in patients with DRE, although a prospective study would need to be conducted to validate these findings.

Identification and referral of patients with refractory epilepsy from the primary to the tertiary care interface in New South Wales, Australia

OBJECTIVES

This mixed-method feasibility study conducted in New South Wales (NSW), Australia, aimed to explore clinical practices around the identification of patients with refractory epilepsy and referral from primary care to Tertiary Epilepsy Centers. The perceptions of general practitioners, neurologists, and adults living with refractory epilepsy were considered.

METHODS

Fifty-two data collection events were achieved through 22 semi-structured interviews with six neurologists and 12 adults who currently have, or have had refractory epilepsy, and four family members, 10 clinical observations of patient consultations and 20 surveys with general practitioners. A thematic analysis was conducted on the qualitative data alongside assessment of observational fieldnotes and survey data.

FINDINGS

Two main themes emerged: 1) Patient healthcare pathways and care experiences highlighted the complex and deeply contextualized experiences of both patients and healthcare professionals, from first identification of people's seizures, in primary and community care settings, to referral to Tertiary Epilepsy Centers, shedding light on a fragmented, nonstandardized referral process, influenced by both individual and shared-care practices. 2) Factors impacting referrals and patient pathways indicated that onward referral to a Tertiary Epilepsy Center is affected by the knowledge, or the lack thereof, of healthcare professionals regarding treatment options. Barriers include limited person-centered care, shared decision-making, and refractory epilepsy education for healthcare professionals, which can delay patients' disease identification and can hinder speedy referral pathways and processes, in Australia for up to 17 years. In addition, person-centered communication around care pathways is affected by relationships between clinicians, patients, and family members.

CONCLUSION

This study has identified a noticeable lack of standardized care across epilepsy-related healthcare sectors, which recognizes a need for developing and implementing clearer epilepsy-related guidelines and Continuing Professional Development in the primary and community care settings. This, however, requires greater collaboration and commitment in the primary, community, and tertiary care sectors to address the ongoing misconceptions around professional roles and responsibilities to optimize shared-care practices. Ultimately, prioritizing person-centered care on both patients' and professionals' agendas, in order to improve satisfaction with care experiences of people living with complex epilepsy.

Utility of invasive electroencephalography in children 3 years old and younger with refractory epilepsy

OBJECTIVE

Early surgical intervention for pediatric refractory epilepsy is increasingly advocated as surgery has become safer and data have demonstrated improved outcomes with early seizure control. There is concern that the risks associated with staged invasive electroencephalography (EEG) in very young children outweigh the potential benefits. Here, the authors present a cohort of children with refractory epilepsy who were referred for invasive monitoring, and they evaluate the role and safety of staged invasive EEG in those 3 years old and younger.

METHODS

The authors conducted a retrospective review of children 3 years and younger with epilepsy, who had been managed surgically at two institutions between 2001 and 2015. A cohort of pediatric patients older than 3 years of age was used for comparison. Demographics, seizure etiology, surgical management, surgical complications, and adverse events were recorded. Statistical analysis was completed using Stata version 13. A p < 0.05 was considered statistically significant. Fisher's exact test was used to compare proportions.

RESULTS

Ninety-four patients (45 patients aged ≤ 3 [47.9%]) and 208 procedures were included for analysis. Eighty-six procedures (41.3%) were performed in children younger than 3 years versus 122 in the older cohort (58.7%). Forty-two patients underwent grid placement (14 patients aged ≤ 3 [33.3%]); 3 of them developed complications associated with the implant (3/42 [7.14%]), none of whom were among the younger cohort. Across all procedures, 11 complications occurred in the younger cohort versus 5 in the older patients (11/86 [12.8%] vs 5/122 [4.1%], p = 0.032). Two adverse events occurred in the younger group versus 1 in the older group (2/86 [2.32%] vs 1/122 [0.82%], p = 0.571). Following grid placement, 13/14 younger patients underwent guided resections compared to 20/28 older patients (92.9% vs 71.4%, p = 0.23).

CONCLUSIONS

While overall complication rates were higher in the younger cohort, subdural grid placement was not associated with an increased risk of surgical complications in that population. Invasive electrocorticography informs management in very young children with refractory, localization-related epilepsy and should therefore be used when clinically indicated.

Placebo in epilepsy

Placebos impact epilepsy in a number of ways. Through randomized clinical trials, explicit clinical use, and also through implicit clinical use, placebos play a role in epilepsy. This chapter will discuss the reasons placebo is used, the determinants of placebo response in epilepsy, observations about placebo specific to epilepsy, and ways in which clinical trial design is impacted by placebo.

Value of stereoelectroencephalography (SEEG)-guided radiofrequency thermocoagulation in treating drug-resistant focal epilepsy

Stereoelectroencephalography (SEEG) has been widely used in the presurgical evaluation of patients with medically intractable epilepsy. In the past, SEEG was commonly used as a method for mapping and localizing the epileptogenic zone (EZ). Since 2004, several studies have been conducted to examine the effectiveness of SEEG-guided radiofrequency thermocoagulation (RF-TC) in treating refractory epilepsy. However, the seizure-free and responder rates varied greatly across studies. We aimed to analyze the outcome of 56 patients who were treated with SEEG-guided RF-TC to evaluate the effectiveness of this treatment. SEEG-guided RF-TC can be considered as a treatment for refractory epilepsy. However, due to its limited efficacy, SEEG-guided RF-TC might be regarded as a temporary treatment performed under SEEG rather than a promising treatment for refractory epilepsy.

Microstructural Investigations of the Visual Pathways in Pediatric Epilepsy Neurosurgery: Insights From Multi-Shell Diffusion Magnetic Resonance Imaging

Background

Surgery is a key approach for achieving seizure freedom in children with focal onset epilepsy. However, the resection can affect or be in the vicinity of the optic radiations. Multi-shell diffusion MRI and tractography can better characterize tissue structure and provide guidance to help minimize surgical related deficits. Whilst in adults tractography has been used to demonstrate that damage to the optic radiations leads to postoperative visual field deficits, this approach has yet to be properly explored in children.

Objective

To demonstrate the capabilities of multi-shell diffusion MRI and tractography in characterizing microstructural changes in children with epilepsy pre- and post-surgery affecting the occipital, parietal or temporal lobes.

Methods

Diffusion Tensor Imaging and the Spherical Mean Technique were used to investigate the microstructure of the optic radiations. Furthermore, tractography was used to evaluate whether pre-surgical reconstructions of the optic radiations overlap with the resection margin as measured using anatomical post-surgical T1-weighted MRI.

Results

Increased diffusivity in patients compared to controls at baseline was observed with evidence of decreased diffusivity, anisotropy, and neurite orientation distribution in contralateral hemisphere after surgery. Pre-surgical optic radiation tractography overlapped with post-surgical resection margins in 20/43 (46%) children, and where visual data was available before and after surgery, the presence of overlap indicated a visual field deficit.

Conclusion

This is the first report in a pediatric series which highlights the relevance of tractography for future pre-surgical evaluation in children undergoing epilepsy surgery and the usefulness of multi-shell diffusion MRI to characterize brain microstructure in these patients.

Epilepsy surgery for refractory seizures: a systematic review and meta-analysis in different complications

Background

Nearly one-third of epilepsy patients are refractory/resistant to medical treatment. Developments made in surgical techniques have significantly increased the effectiveness and safety of these techniques, as such techniques have been demonstrated to improve seizure control/freedom outcomes.

Objectives

The aim of this systematic review and meta-analysis was to evaluate the complications of epilepsy surgery.

Patient and methods

The searches were conducted by three independent researchers to find the relevant studies published from January 1, 2009, until the end of January 6, 2019. For English published statistical studies, all studies conducted on epileptic patients who have undergone epilepsy surgery were included.

Statistical analysis

A meta-analysis was conducted in the STATA14 statistical software.

Results

A total of 6735 patients with epilepsy who had undergone the epilepsy surgery were studied. The overall prevalence of complications was 5%. The prevalence of major and minor complications was 5.4% and 3.2% respectively. The prevalence of complications related to the temporal epilepsy surgery and the extra-temporal epilepsy surgery based on 3 studies was 7.9% and 8.2 % respectively. The frequency of neurological and surgical complications after epilepsy surgery was 4.4% and 4.1% respectively.

Conclusion

The overall rate of complications caused by epilepsy surgery was reasonably low (5%), implying that epilepsy surgery especially temporal lobe resection can be safe preferably when performed by an experienced surgeon.

The experience of the multidisciplinary team in epilepsy management from a resource-limited country

OBJECTIVE

The use of multidisciplinary teams (MDTs) is a global trend in disease management, while China is still at the exploratory stage MDTs. We aimed to summarize our experience and assess the impact of MDT use in managing patients with epilepsy and optimizing their seizure outcomes.

METHODS

Our MDT is staffed with skilled epileptologists, electroencephalography experts, neurosurgeons, child neurologists, radiologists, and psychiatrists. The MDT discussion has been carried out once or twice a week since 2013. We reviewed our consecutive patients discussed at our MDT from March 2013 to December 2017. The detailed clinical characteristics, suggestions, and follow-up data were collected and analyzed.

RESULTS

A total of 1088 patients (604 male, 484 female) were included in this study. The median age at MDT discussion was 21 years (range 10 months to 79 years). Three hundred eighty-seven patients (35.6%) were younger than18 years of age. The median age at seizure onset was 12 years (range 2 days to 77 years). Most patients (80.4%) had at least one seizure per month and most (77%) took 2 or more antiepileptic drugs. A total of 70.6% of patients reached the standard of drug-resistant epilepsy and 74.2% of brain magnetic resonance imaging (MRI) studies detected positive findings. After detailed MDT discussion, 18 patients were diagnosed as having nonepileptic diseases, including psychogenic nonepileptic seizure, syncope, sleep disorder, paroxysmal kinesigenic dyskinesia, withdrawal symptom, and cerebral palsy. Three hundred eighty-two patients (35.1%) were suitable for resective surgery. Among the postoperative patients successfully followed up for more than 1 year, 72.7% (136/187) received favorable outcomes (Engel class I). The seizure-free rate was 78.6% after temporal lobe surgery and 58.9% after extratemporal surgery.

SIGNIFICANCE

Epilepsy management can be optimized through MDT discussion to attain accurate diagnosis and favorable seizure outcomes. There is still room for MDT improvement in resource-limited countries.

[Prognosis for surgical treatment of pharmacoresistant epilepsy: the role of mental and cognitive disorders]

This review focuses on the role of mental and cognitive disorders in the prognosis for surgical treatment of pharmacoresistant epilepsy. The authors analyze historical aspects of the surgical treatment of epilepsy and present current data on the prognosis of operative intervention with respect to seizure control, cognitive functioning, and psychiatric disorders. The psychiatrist's role in the structure of preoperative and postoperative management of patients is considered.

Dual responsive neurostimulation implants for epilepsy

Closed-loop brain-responsive neurostimulation via the RNS System is a treatment option for adults with medically refractory focal epilepsy. Using a novel technique, 2 RNS Systems (2 neurostimulators and 4 leads) were successfully implanted in a single patient with bilateral parietal epileptogenic zones. In patients with multiple epileptogenic zones, this technique allows for additional treatment options. Implantation can be done successfully, without telemetry interference, using proper surgical planning and neurostimulator positioning.Trajectories for the depth leads were planned using neuronavigation with CT and MR imaging. Stereotactic frames were used for coordinate targeting. Each neurostimulator was positioned with maximal spacing to avoid telemetry interference while minimizing patient discomfort. A separate J-shaped incision was used for each neurostimulator to allow for compartmentalization in case of infection. In order to minimize surgical time and risk of infection, the neurostimulators were implanted in 2 separate surgeries, approximately 3 weeks apart.The neurostimulators and leads were successfully implanted without adverse surgical outcomes. The patient recovered uneventfully, and the early therapy settings over several months resulted in preliminary decreases in aura and seizure frequency. Stimulation by one of the neurostimulators did not result in stimulation artifacts detected by the contralateral neurostimulator.

Quality of Life and Its Determinants in Adult Drug Refractory Epilepsy Patients Who Were Not Candidates for Epilepsy Surgery: A Correlational Study

Background and Purpose

This study was performed to elucidate quality of life (QOL) and its determinants in adult drug refractory epilepsy (DRE) patients who were not candidates for epilepsy surgery.

Methods

A correlational study was performed at the center of excellence, epilepsy between July 2014 to June 2016. All consecutive DRE patients who were not candidates for epilepsy surgery were enrolled. The outcomes were QOL, assessed using the quality of life inventory in epilepsy-31 items (QOLIE-31) inventory and the correlation of QOL with epilepsy-related variables like seizure severity and frequency. We also compared current QOL with QOL during the pre-surgical evaluation to strengthen our study outcome.

Results

A total of 129 adult patients were enrolled over two years. The mean age was 26.5 ± 6.7 years and male: female ratio was 3: 1. The mean age at epilepsy onset was 9.6 ± 6.6 years and mean duration of epilepsy was 14.9 ± 7.5 years. There was lower seizure frequency than during pre-surgical evaluation in 37.2% of patients, while in 62.8% the seizure frequency remained the same or was higher. Nine (6.98%) patients became seizure free. In comparison to QOL status during the pre-surgical evaluation, there was statistically significant worsening of QOL in all domains (p < 0.01). Seizure severity significantly correlated with almost all QOL domains (p ≤ 0.01), while seizure frequency significantly correlated with only the single domain of overall QOL (p = 0.03).

Conclusions

The QOL of DRE patients who were not candidates for epilepsy surgery worsened relative to the QOL during the pre-surgical evaluation period. Seizure severity significantly correlated with QOL, but seizure frequency did not.

Diagnostic and prognostic value of noninvasive long-term video-electroencephalographic monitoring in epilepsy surgery: A systematic review and meta-analysis from the E-PILEPSY consortium

OBJECTIVE

The European Union-funded E-PILEPSY network (now continuing within the European Reference Network for rare and complex epilepsies [EpiCARE]) aims to harmonize and optimize presurgical diagnostic procedures by creating and implementing evidence-based guidelines across Europe. The present study evaluates the current evidence on the diagnostic accuracy of long-term video-electroencephalographic monitoring (LTM) in identifying the epileptogenic zone in epilepsy surgery candidates.

METHODS

MEDLINE, Embase, CENTRAL, and ClinicalTrials.gov were searched for relevant articles. First, we used random-effects meta-analytical models to calculate pooled estimates of sensitivity and specificity with respect to postsurgical seizure freedom. In a second phase, we analyzed individual patient data in an exploratory fashion, assessing diagnostic accuracy within lesional and nonlesional temporal lobe epilepsy (TLE) and extratemporal lobe epilepsy (ETLE) patients. We also evaluated seizure freedom rate in the presence of "localizing" or "nonlocalizing" LTM within each group. The quality of evidence was assessed using the QUADAS-2 tool and the GRADE approach.

RESULTS

Ninety-four studies were eligible. Forty-four were included in sensitivity meta-analysis and 34 in specificity meta-analysis. Pooled sensitivity was 0.70 (95% confidence interval [CI] = 0.60-0.80) and specificity was 0.40 (95% CI = 0.27-0.54). Subgroup analysis was based on individual data of 534 patients (41% men). In lesional TLE patients, sensitivity was 0.85 (95% CI = 0.81-0.89) and specificity was -0.19 (95% CI = 0.13-0.28). In lesional ETLE patients, a sensitivity of 0.47 (95% CI = 0.36-0.58) and specificity of 0.35 (95% CI = 0.21-0.53) were observed. In lesional TLE, if LTM was localizing and concordant with resection site, the seizure freedom rate was 247 of 333 (74%), whereas in lesional ETLE it was 34 of 56 (61%). The quality of evidence was assigned as "very low."

SIGNIFICANCE

Long-term video-electroencephalographic monitoring is associated with moderate sensitivity and low specificity in identification of the epileptogenic zone. Sensitivity is remarkably higher in lesional TLE compared to lesional ETLE. Substantial heterogeneity across the studies indicates the need for improved design and quality of reporting.

Addressing barriers to surgical evaluation for patients with epilepsy

OBJECTIVE

Patients with poorly controlled seizures are at elevated risk of epilepsy-related morbidity and mortality. For patients with drug-resistant epilepsy that is focal at onset, epilepsy surgery is the most effective treatment available and offers a 50-80% cure rate. Yet, it is estimated that only 1% of patients with drug-resistant epilepsy undergo surgery in a timely fashion, and delays to surgery completion are considerable. The aim of this study was to increase availability and decrease delay of surgical evaluation at our epilepsy center for patients with drug-resistant epilepsy by removing process barriers.

METHODS

For this quality improvement (QI) initiative, we convened a multidisciplinary team to construct a presurgical pathway process map and complete root cause analysis. This inquiry revealed that the current condition allowed patients to proceed through the pathway without centralized oversight. Therefore, we appointed an epilepsy surgery nurse manager, and under her direction, multiple additional process improvement interventions were applied. We then retrospectively compared preintervention (2014-2015) and postintervention (2016-2017) cohorts of patient undergoing the presurgical pathway. The improvement measures were patient throughput and pathway sojourn times. As a balancing measure, we considered the proportion of potentially eligible patients (epilepsy monitoring unit (EMU) admissions) who ultimately completed epilepsy surgery.

RESULTS

Following our intervention, patient throughput was substantially increased for each stage of the presurgical pathway (32%-96% growth). However, patient sojourn times were not improved overall. No difference was observed in the proportion of possible candidates who ultimately completed epilepsy surgery.

SIGNIFICANCE

Although process improvement expanded the number of patients who underwent epilepsy surgical evaluation, we experienced concurrent prolongation of the time from pathway initiation to completion. Ongoing improvement cycles will focus on newly identified residual sources of bottleneck and delay.

Seizure outcome in pediatric medically refractory temporal lobe epilepsy surgery: selective amygdalohippocampectomy versus anterior temporal lobectomy

OBJECTIVE The aim of this study was to investigate long-term seizure outcome, rate of reoperation, and postoperative neuropsychological performance following selective amygdalohippocampectomy (SelAH) or anterior temporal lobectomy (ATL) in pediatric patients with medically refractory temporal lobe epilepsy (TLE). METHODS The authors performed a retrospective review of cases of medically refractory pediatric TLE treated initially with either SelAH or ATL. Standardized pre- and postoperative evaluation included seizure charting, surface and long-term video-electroencephalography, 1.5-T MRI, and neuropsychological testing. RESULTS A total of 79 patients treated initially with SelAH (n = 18) or ATL (n = 61) were included in this study, with a mean follow-up of 5.3 ± 4 years (range 1-16 years). The patients' average age at initial surgery was 10.6 ± 5 years, with an average surgical delay of 5.7 ± 4 years between seizure onset and surgery. Seizure freedom (Engel I) following the initial operation was significantly more likely following ATL (47/61, 77%) than SelAH (8/18, 44%; p = 0.017, Fisher's exact test). There was no statistically significant difference in the proportion of patients with postoperative neuropsychological deficits following SelAH (8/18, 44%) or ATL (21/61, 34%). However, reoperation was significantly more likely following SelAH (8/18, 44%) than after ATL (7/61, 11%; p = 0.004) and was more likely to result in Engel I outcome for ATL after failed SelAH (7/8, 88%) than for posterior extension after failed ATL (1/7, 14%; p = 0.01). Reoperation was well tolerated without significant neuropsychological deterioration. Ultimately, including 15 reoperations, 58 of 79 (73%) patients were free from disabling seizures at the most recent follow-up. CONCLUSIONS SelAH among pediatric patients with medically refractory unilateral TLE yields significantly worse rates of seizure control compared with ATL. Reoperation is significantly more likely following SelAH, is not associated with incremental neuropsychological deterioration, and frequently results in freedom from disabling seizures. These results are significant in that they argue against using SelAH for pediatric TLE surgery.

Deep brain stimulation for seizure control in drug-resistant epilepsy

Antiepileptic drugs prevent morbidity and death in a large number of patients suffering from epilepsy. However, it is estimated that approximately 30% of epileptic patients will not have adequate seizure control with medication alone. Resection of epileptogenic cortex may be indicated in medically refractory cases with a discrete seizure focus in noneloquent cortex. For patients in whom resection is not an option, deep brain stimulation (DBS) may be an effective means of seizure control. Deep brain stimulation targets for treating seizures primarily include the thalamic nuclei, hippocampus, subthalamic nucleus, and cerebellum. A variety of stimulation parameters have been studied, and more recent advances in electrical stimulation to treat epilepsy include responsive neurostimulation. Data suggest that DBS is effective for treating drug-resistant epilepsy.

Unilateral temporal interictal epileptiform discharges correctly predict the epileptogenic zone in lesional temporal lobe epilepsy

OBJECTIVE

To evaluate the necessity of recording ictal electroencephalography (EEG) in patients with temporal lobe epilepsy (TLE) considered for resective surgery who have unilateral temporal interictal epileptiform discharges (IEDs) and concordant ipsitemporal magnetic resonance imaging (MRI) pathology. To calculate the necessary number of recorded EEG seizure patterns (ESPs) to achieve adequate lateralization probability.

METHODS

In a retrospective analysis, the localization and lateralization of interictal and ictal EEG of 304 patients with lesional TLE were analyzed. The probability of further contralateral ESPs was calculated based on a total of 1967 recorded ESPs, using Bayes' theorem.

RESULTS

Two hundred seventy-one patients had unilateral TLE, and in 98% of them (265 of 271), IEDs were recorded during video-EEG monitoring. Purely unilateral temporal IEDs were present in 61% (166 of 271 patients). Ipsilateral temporal MRI pathology was found in 83% (138 of 166). Ictal EEG was concordant with the clinical side of TLE in 99% (136 of 138) of these patients. Two patients had discordant ictal EEG with both ipsilateral and contralateral ESPs. Epilepsy surgery with resection in the lesioned temporal lobe was still performed, and both patients remain seizure-free. Probability calculations demonstrate that at least 6 recorded unilateral ESPs result in a >95% probability for a concordance of >0.9 of any further ESPs.

SIGNIFICANCE

The combination of purely unilateral temporal IED with ipsitemporal MRI pathology is sufficient to identify the epileptogenic zone, and the recording of ictal ESP did not add any surgically relevant information in these 138 patients. Rarely, discordant ESPs might be recorded, but the surgical outcome remains excellent after surgery on the lesioned side.

Cognition in epilepsy: current clinical issues of interest

PURPOSE OF REVIEW

This review provides an update and summary of recent neuropsychological findings in epilepsy focusing on three major clinical topics among the many developments in the field. We will critically outline the current state with regard to cognition in new-onset epilepsies, social cognition in epilepsy, and the long-term outcome of epilepsy surgery and the cognitive outcomes of superselective surgical procedures.

RECENT FINDINGS

Current studies indicate that neuropsychological impairments are prevalent already at the onset of epilepsy and even before, social cognition (i.e., emotion recognition and theory of mind) is impaired in different epilepsy populations, the long-term outcome of epilepsy surgery is mostly characterized by a stable or even improved cognitive status, and superselective epilepsy surgeries are associated with a promising neuropsychological outcome.

SUMMARY

The high prevalence of cognitive deficits around epilepsy onset challenges the assumption that epilepsy is the major cause of cognitive problems and calls for early neuropsychological diagnostics. Social cognition seems to be a relevant domain that is not yet routinely considered in epilepsy. The cognitive long-term outcome of epilepsy surgery is mostly positive. Stereotactic thermocoagulation and gamma knife surgery appear to be cognitively safe procedures.

Surgical versus medical treatment of drug-resistant epilepsy: A systematic review and meta-analysis

OBJECTIVE

Surgery and drug therapy are the two main treatments for refractory epilepsy. However, to date, there has not been an adequate comparison of the outcomes of these two treatments. This systematic review compared the overall outcome of surgery and medical treatment in patients with drug-resistant epilepsy.

METHODS

Articles published in Embase, Medline, Pubmed, and the Cochrane library were searched from their inception until June 2016.

RESULTS

Twenty of the eighty-one (24.7%) full-text articles reviewed fulfilled the eligibility criteria and were included in the meta-analysis. Of 1800 patients with drug-resistant epilepsy, 526 of 923 patients (57.0%) in the surgery group were seizure-free compared with 134 of 877 patients (15.3%) in the medical treatment group (19 studies, risk ratio (RR)=3.72, 95% confidence interval (CI) [2.75-5.03]; P<0.00001, I²=53%). In addition, more patients were off antiepileptic drugs (AEDs) in the surgical group (3 studies, n=438, RR=4.76, 95% CI [2.21, 10.28], P<0.0001, I²=0%). Although different studies used different questionnaires to assess patient quality of life (QOL) in both treatment groups, the overall postintervention QOL scores were higher in the surgery than in the medical treatment group, by SMD (6 studies, n=459, SMD=0.61, 95% CI [0.23, 0.98], P=0.002, I²=66%).

CONCLUSION

As the complications of interventions, declines in memory, and word recall/naming were not assessed in the meta-analysis, the conclusions are limited to seizure-free, AED use, and QOL. The current evidence indicate that compared with medical treatment, surgery is more likely to achieve seizure-free, off AEDs, and better QOL.

The role of stereoelectroencephalography (SEEG) in reevaluation of epilepsy surgery failures

Management of patients after initial epilepsy surgical failure is challenging. In this study, we report our experience in using the stereoelectroencephalography (SEEG) method in the reevaluation of patients after initial epilepsy surgical failure. We selected 28 patients examined through SEEG in our department for drug-resistant focal epilepsy following initial epilepsy surgical failure. For each patient, the residual seizure onset zone (rSOZ) as defined by SEEG was classified as either contiguous if the seizure onset zone (SOZ) was focal and close to the surgical cavity (same lobe) or noncontiguous in cases where the SOZ included site(s) distant from the surgical cavity. The rSOZ was defined according to visual analysis of SEEG traces completed by an estimation of the epileptogenicity index (EI). A second surgical procedure was performed in 12 patients (45%). A favorable outcome (Engel class I or II) was obtained in 9/12 patients (6 in Engel class I, 50%). The proportion of patients that had reoperation was higher in the contiguous group (80%) than in the noncontiguous group (22%) (p=0.02). A rSOZ localized in close relation to the initial surgical resection zone (contiguous group) was found in 10 patients (35%). Among them, 8 have since undergone reoperation, and a good outcome (Engel class I) was achieved in 5/8 (63%). A rSOZ involving a distant region from the first surgery was observed in 18 patients (65%) (noncontiguous group). Among them, only 4 have undergone reoperation, leading to a failure in 2 (Engel class III or IV) and a good outcome in 2 (IA). Ten patients had a first standard temporal lobectomy, and in 50% of these cases, the insula was involved in the rSOZ. Stereoelectroencephalography offers a unique way to evaluate the rSOZ at the individual level and thus guide further surgical decision-making. The best results are observed in patients having a focal rSOZ close to the site of the surgical resection in the first surgery.

Prognostic significance of postoperative spikes varied in different surgical procedures for mesial temporal sclerosis

PURPOSE

We conducted this study to compare the occurrence and prognostic significance of early postoperative interictal epileptiform discharges (IEDs) on seizure outcomes between corticoamygdalohippocampectomy (CAH) and selective amygdalohippocampectomy (SAH).

METHODS

We reviewed our database of patients who had epilepsy surgery with hippocampus atrophy or signal changes on brain MRIs and pathology of mesial temporal sclerosis. One hundred and seventy-seven CAH and 39 SAH patients were enrolled. Postoperative EEG within 30days, other preoperative variables and seizure outcome 2years after surgery were obtained for analysis. Engel's IA and IB were defined as seizure-free.

RESULTS

There was no significant difference in the seizure-free rate between the two procedures (127 (71.8%) of CAH vs 30 (76.9%) of SAH, p=0.51). Postoperative IEDs were more frequently seen in the SAH group (64.1%) than in the CAH group (29.9%), p<0.001. The IEDs in the SAH group did not show correlation with the seizure outcome 2 years after surgery. In the CAH group, patients who had no postoperative IEDs showed a higher seizure-free rate compared to those with IEDs (78.2% vs 56.6%, p=0.003; OR 2.267, 95% CI 1.09-4.73, p=0.029 in multivariate logistic regression).

CONCLUSIONS

Early postoperative IEDs are more frequently seen in SAH than in CAH. Unlike in patients with CAH, the presence of IEDs after SAH was not a predictor of seizure recurrence. The type of surgery should be considered while utilizing postoperative IEDs for evaluating the prognosis.

Surgical Treatment of Mesiotemporal Lobe Epilepsy: Which Approach is Favorable?

BACKGROUND

Mesiotemporal lobe epilepsy is one of the most frequent causes for pharmacoresistant epilepsy. Different surgical approaches to the mesiotemporal area are used.

OBJECTIVE

To analyze epileptological and neuropsychological results as well as complications of different surgical strategies.

METHODS

This retrospective study is based on a consecutive series of 458 patients all harboring pharmacoresistant mesiotemporal lobe epilepsy. Following procedures were performed: standard anterior temporal lobectomy, anterior temporal or key-hole resection, extended lesionectomy, and transsylvian and subtemporal selective amygdalohippocampectomy. Postoperative outcome was evaluated according to different surgical procedures.

RESULTS

Overall, 1 yr after surgery 315 of 432 patients (72.9%) were classified Engel I; in particular, 72.8% were seizure-free after anterior temporal lobectomy, 76.9% after key-hole resection, 84.4% after extended lesionectomy, 70.3% after transylvian selective amygdalohippocampectomy, and 59.1% after subtemporal selective amygdalohippocampectomy. No significant differences in seizure outcome were found between different resective procedures, neither in short-term nor long-term follow-up. There was no perioperative mortality. Permanent morbidity was encountered in 4.4%. There were no significant differences in complications between different resection types. In the majority of patients, selective attention improved following surgery. Patients after left-sided operations performed significantly worse regarding verbal memory as compared to right-sided procedures. However, surgical approach had no significant effect on memory outcome.

CONCLUSION

Different surgical approaches for mesiotemporal epilepsy analyzed resulted in similar epileptological, neuropsychological results, and complication rates. Therefore, the approach for the individual patient does not only depend on the specific localization of the epileptogenic area, but also on the experience of the surgeon.

Seizure outcomes of temporal lobe epilepsy surgery in patients with normal MRI and without specific histopathology

BACKGROUND

Seizure outcome following surgery in pharmacoresistant temporal lobe epilepsy patients with normal magnetic resonance imaging and normal or non-specific histopathology is not sufficiently presented in the literature.

METHODS

In a retrospective design, we reviewed data of 263 patients who had undergone temporal lobe epilepsy surgery and identified 26 (9.9%) who met the inclusion criteria. Seizure outcomes were determined at 2-year follow-up. Potential predictors of Engel class I (satisfactory outcome) were identified by logistic regression analyses.

RESULTS

Engel class I outcome was achieved in 61.5% of patients, 50% being completely seizure free (Engel class IA outcome). The strongest predictors of satisfactory outcome were typical ictal seizure semiology (p = 0.048) and localised ictal discharges on scalp EEG (p = 0.036).

CONCLUSION

Surgery might be an effective treatment choice for the majority of these patients, although outcomes are less favourable than in patients with magnetic resonance imaging-defined lesional temporal lobe epilepsy. Typical ictal seizure semiology and localised ictal discharges on scalp EEG were predictors of Engel class I outcome.

18F-FDG-PET patterns of surgical success and failure in mesial temporal lobe epilepsy

OBJECTIVE

To search for [¹⁸F]-fluorodeoxyglucose (FDG)-PET patterns predictive of long-term prognosis in surgery for drug-resistant mesial temporal lobe epilepsy (MTLE) due to hippocampal sclerosis (HS).

METHODS

We analyzed metabolic data with [¹⁸F]-FDG-PET in 97 patients with MTLE (53 female participants; age range 15-56 years) with unilateral HS (50 left) and compared the metabolic patterns, electroclinical features, and structural atrophy on MRI in patients with the best outcome after anteromesial temporal resection (Engel class IA, completely seizure-free) to those with a non-IA outcome, including suboptimal outcome and failure. Imaging processing was performed with statistical parametric mapping (SPM5).

RESULTS

With a mean follow-up of >6 years (range 2-14 years), 85% of patients achieved a class I outcome, including 45% in class IA. Class IA outcome was associated with a focal anteromesial temporal hypometabolism, whereas non-IA outcome correlated with extratemporal metabolic changes that differed according to the lateralization: ipsilateral mesial frontal and perisylvian hypometabolism in right HS and contralateral fronto-insular hypometabolism and posterior white matter hypermetabolism in left HS. Suboptimal outcome presented a metabolic pattern similar to the best outcome but with a larger involvement of extratemporal areas, including the contralateral side in left HS. Failure was characterized by a mild temporal involvement sparing the hippocampus and relatively high extratemporal hypometabolism on both sides. These findings were concordant with electroclinical features reflecting the organization of the epileptogenic zone but were independent of the structural abnormalities detected on MRI.

CONCLUSIONS

[¹⁸F]-FDG-PET patterns help refine the prognostic factors in MTLE and should be implemented in predictive models for epilepsy surgery.

Cost-Utility of Video-Electroencephalography Monitoring Followed by Surgery in Adults with Drug-Resistant Focal Epilepsy in Thailand

OBJECTIVES

This study assessed whether video-electroencephalography (VEEG) monitoring followed by surgery was cost-effective in adult patients with drug-resistant focal epilepsy under Thai health care context, as compared with continued medical treatment without VEEG.

METHODS

The total cost (in Thai Baht, THB) and effectiveness (in quality-adjusted life years, QALYs) were estimated over a lifetime horizon, using a decision tree and a Markov model. Data on short-term surgical outcomes, direct health care costs, and utilities were collected from Thai patients in a specialized hospital. Long-term outcomes and relative effectiveness of the surgery over medical treatment were derived, using systematic reviews of published literature.

RESULTS

Seizure-free rates at years 1 and 2 after surgery were 79.4% and 77.8%, respectively. Costs of VEEG and surgery plus 1-year follow-up care were 216,782 THB, of which the VEEG and other necessary investigations were the main cost drivers (42.8%). On the basis of societal perspective, the total cost over a 40-year horizon accrued to 1,168,679 THB for the VEEG option, 64,939 THB higher than that for no VEEG. The VEEG option contributed to an additional 1.50 QALYs over no VEEG, resulting in an incremental cost-effectiveness ratio of 43,251 THB (USD 1236) per 1 QALY gained. Changes in key parameters had a minimal impact on the incremental cost-effectiveness ratio. Accounting for uncertainty, there was an 84% probability that the VEEG option was cost-effective on the basis of Thailand's cost-effective threshold of 160,000 THB/QALY.

CONCLUSIONS

For patients with drug-resistant epilepsy, VEEG monitoring followed by epilepsy surgery was cost-effective in Thailand. Therefore it should be recommended for health insurance coverage.

Outcome after epilepsy surgery at the University Hospitals Leuven 1998-2012

We performed a retrospective outcome study of 199 patients who underwent resective epilepsy surgery from 1998 to 2012 and had a minimum of one-year follow-up at the University Hospitals Leuven. Our aim was to assess seizure outcome, prognostic factors for seizure outcome and complication rate. Good seizure outcome after surgery was 38 % at 5 years and 34 % at 10 years follow-up. Good seizure outcome over the previous year at last follow-up, however, was 77 %, which could be explained by the 'running-down phenomenon', i.e. seizure freedom after initial recurrent epilepsy in 32 % of the patients, mainly after temporal lobe surgery. Good seizure outcome for at least 1 year at the last visit was 82 % for temporal and 62 % for extra-temporal lobe interventions. Other variables predictive of a good seizure outcome were not identified. Permanent complications of epilepsy surgery were observed in 31 %. The most important were word finding difficulties (22 %), depression (18 %) and memory deficits (12 %). In conclusion, epilepsy surgery is an excellent treatment option for selected patients, with a good seizure outcome in around 80 % of patients and complications in about 30 %.

Natural course of treated epilepsy and medico-social outcomes. Turku studies. Part II

Introduction. Population-based data on the prognosis of childhood-onset epilepsy were almost nonexistent in the 1960s. This prompted me to start an epidemiological prospective study on children with epilepsy.

Aim. To study the medical and social outcome of children with epilepsy.

Methods. The most important personal data on the natural course and outcome were reviewed and compared with the relevant data of other investigators.

Results and discussion. The natural course of treated epilepsy is remitting, uninterrupted by relapse (in 48%); a remitting-relapsing course (interrupted by relapses, in terminal remission) (19%); worsening course (early or late remission followed by drug-resistant epilepsy) (14%); and never in ≥5-year remission (drug resistance) (19%) The medical and social outcomes based on my unique, five decades followed cohort show that most subjects are in 10-year remission without medications, which is the definition of resolved epilepsy. Normal or subnormal IQ, non-symptomatic etiology, and low seizure frequency both in the first year of AED treatment and prior to medication appear to be clinical predictors of cure in childhood-onset epilepsy. Subjects with 1-year remission during the first five years form onset of treatment have more than 10-fold chance for entering 5-year terminal remission vs those who have no 1-year remission during the first five years. Even about one fourth of difficult-to-treat subjects become seizure free on medication and more than half of them enter one or more 5-year remissions. Epilepsy has a substantial impact on quality of life even in those who are seizure free off medication for many years and particularly those not in remission or in remission but still on medication.

Conclusions. The prognosis is excellent for medical and social outcome. The successful outcome is confirmed by several longitudinal studies from recent decades. Good response to early drug therapy does not necessarily guarantee a favorable seizure outcome, and even a late good response may still predict a successful prognosis. Our life-cycle study is being continued and targets to answer the question whether or not childhood-onset epilepsy is a risk factor for premature and/or increased incidence of mental impairment and dementia.

Response to placebo in clinical epilepsy trials--Old ideas and new insights

Randomized placebo-controlled trials are a mainstay of modern clinical epilepsy research; the success or failure of innovative therapies depends on proving superiority to a placebo. Consequently, understanding what drives response to placebo (including the "placebo effect") may facilitate evaluation of new therapies. In this review, part one will explore observations about placebos specific to epilepsy, including the relatively higher placebo response in children, apparent increase in placebo response over the past several decades, geographic variation in placebo effect, relationship to baseline epilepsy characteristics, influence of nocebo on clinical trials, the possible increase in (SUDEP) in placebo arms of trials, and patterns that placebo responses appear to follow in individual patients. Part two will discuss the principal causes of placebo responses, including regression to the mean, anticipation, classical conditioning, the Hawthorne effect, expectations from symbols, and the natural history of disease. Included in part two will be a brief overview of recent advances using simulations from large datasets that have afforded new insights into causes of epilepsy-related placebo responses. In part three, new developments in study design will be explored, including sequential parallel comparison, two-way enriched design, time to pre-randomization, delayed start, and cohort reduction techniques.

Millimeter-scale epileptiform spike propagation patterns and their relationship to seizures

OBJECTIVE

Current mapping of epileptic networks in patients prior to epilepsy surgery utilizes electrode arrays with sparse spatial sampling (∼1.0 cm inter-electrode spacing). Recent research demonstrates that sub-millimeter, cortical-column-scale domains have a role in seizure generation that may be clinically significant. We use high-resolution, active, flexible surface electrode arrays with 500 μm inter-electrode spacing to explore epileptiform local field potential (LFP) spike propagation patterns in two dimensions recorded from subdural micro-electrocorticographic signals in vivo in cat. In this study, we aimed to develop methods to quantitatively characterize the spatiotemporal dynamics of epileptiform activity at high-resolution.

APPROACH

We topically administered a GABA-antagonist, picrotoxin, to induce acute neocortical epileptiform activity leading up to discrete electrographic seizures. We extracted features from LFP spikes to characterize spatiotemporal patterns in these events. We then tested the hypothesis that two-dimensional spike patterns during seizures were different from those between seizures.

MAIN RESULTS

We showed that spatially correlated events can be used to distinguish ictal versus interictal spikes.

SIGNIFICANCE

We conclude that sub-millimeter-scale spatiotemporal spike patterns reveal network dynamics that are invisible to standard clinical recordings and contain information related to seizure-state.

Perspectives of epilepsy surgery in resource-poor countries: a study in Georgia

BACKGROUND

To identify patients with concordant seizure semiology, interictal epileptiform discharges on standard EEG and brain MRI changes to define the patients with pharmacoresistant epilepsy (PRE) who would be suitable for epilepsy surgery according to non-invasive protocol.

METHODS

The medical records of the patients with epilepsy seen in Epilepsy Center of Institute of Neurology and Neuropsychology (ECINN) (Tbilisi, Georgia) were reviewed retrospectively. The diagnostic work-up included neurological examination, standard EEG, and MRI. The degree of concordance of the seizure semiology, EEG, and neuroimaging was used to determine the potential candidates for surgery. The probability of seizure freedom rate was estimated based on known predictive values of anatomical, electrophysiological, and semiological characteristics.

RESULTS

A total of 83 (25 %) patients met the criteria of PRE. Fourteen (17 %) patients had complete concordance of seizure semiology, MRI, and EEG. Out of these patients, 11 had mesial temporal sclerosis on MRI and three had focal cortical dysplasia (FCD). Estimated seizure-free surgical success rate in this group was 75-95 % without the need for further investigations. Out of 25 (30 %) non-lesional MRI cases, the concordance of seizure semiology and EEG was in nine patients with probable success rate up to 60 %. Thirteen patients (16 %) had discordant EEG and MRI data and were not suitable for surgery without further testing.

CONCLUSIONS

A significant portion of PRE patients with concordant anatomical, electrophysiological, and semiological characteristics can be treated surgically in resource-limited countries. Nevertheless, most patients will still require further investigation for proper localization of epileptogenic focus.

The preoperative evaluation and surgical treatment of epilepsy

BACKGROUND

One-third of all patients with epilepsy have persistent seizures despite medical treatment. If the origin of the seizures can be localized to a particular site in the brain, epilepsy surgery is a treatment option that addresses the cause of the problem.

METHOD

The presurgical assessment and surgical treatment of epilepsy are discussed on the basis of a selective literature review and the authors' clinical experience.

RESULTS

Recent studies give further evidence that surgical treatment is superior to continued medical treatment for patients with seizures of focal origin that persist despite treatment with two antiepileptic drugs. Modern imaging and electrophysiological techniques enable the demonstration of subtle structural and functional changes of the cerebral cortex as a basis for individually tailored surgical resection. 60-80% of surgically treated patients become seizure-free. According to recent reviews, epilepsy surgery is associated with a permanent morbidity of 6% and with a mortality well under 1%; these figures are in the typical range for neurosurgical procedures. In the authors' series, 2% of patients had permanent complications, and the death rate was less than 0.1%.

CONCLUSION

Advances in presurgical assessment and the broad range of available surgical techniques have widened the applicability of surgical treatment for children and adults with medically refractory epilepsy. Patients should be referred early in the course of their disease to an epilepsy center for evaluation of the surgical options.

Clinical outcomes and quality of life following surgical treatment for refractory epilepsy: a systematic review and meta-analysis

Surgery for refractory epilepsy is widely used but the efficacy of this treatment for providing a seizure-free outcome and better quality of life remains unclear.This study aimed to update current evidence and to evaluate the effects of surgery on quality of life in patients with refractory epilepsy.A systematic review and meta-analysis of the literature were conducted and selected studies included 2 groups of refractory epilepsy patients, surgical and nonsurgical.The studies were assessed using the Newcastle-Ottawa Scale. The primary outcome was the seizure-free rate. The secondary outcome was quality of life. Adverse events were also reviewed.After screening, a total of 20 studies were selected: 8 were interventional, including 2 randomized controlled trials, and 12 were observational. All of the studies comprised 1959 patients with refractory epilepsy. The seizure-free rates were significantly higher for patients who received surgery compared with the patients who did not; the combined odds ratio was 19.35 (95% CI = 12.10-30.95, P < 0.001). After adjusting for publication bias the combined odds ratio was 10.25 (95% CI = 5.84-18.00). In both the interventional and observational studies, patients treated surgically had a significantly better quality of life compared with the patients not treated surgically. Complications were listed in 3 studies and the rates were similar in surgical and nonsurgical patients.Our meta-analysis found that for patients with refractory epilepsy, surgical treatment appears to provide a much greater likelihood of seizure-free outcome than nonsurgical treatment, although there is a need for more studies, particularly randomized studies, to confirm this conclusion. Based on more limited data, surgical treatment also appeared to provide a better quality of life and did not seem to increase complications.

Intracranial electroencephalography with subdural and/or depth electrodes in children with epilepsy: techniques, complications, and outcomes

Intracranial electroencephalographic monitoring with subdural and/or depth electrodes is widely used for the surgical localization of epileptic foci in patients with intractable partial epilepsy; however, data on safety and surgical outcome with this technique are still inadequate. The aims of this study were to assess the morbidity of intracranial recordings and the surgical outcomes in epileptic children. We retrospectively reviewed the clinical data for 137 children with epilepsy (mean age at implantation: 12.6 ± 3.8 years) who underwent intracranial monitoring with the implantation of strip or grid subdural electrodes and/or intracerebral depth electrodes from September 2004 to September 2011 at a tertiary epilepsy center in China. Complications were classified using five grades of severity (including mortality) and were further classified as either minor or severe. Outcome was classified according to Engel's classification. Regression analysis was performed to identify risk factors for complications. The mean duration of implantation was 5.3 ± 1.3 days. Among the 133 patients who underwent resection, 65 (48.9%) were seizure free (Engel Class I) at last known follow-up, which was >2 years after surgery for all patients. Also, 31 (23.3%) patients had a significant reduction in seizures (Engel Class II). Complications of any type were documented in 29 (21.7%) patients; 15 of these patients had intracranial hematoma. The results of multivariate analysis showed that the only independent risk factor for intracranial hematoma was number of electrode contacts. The most common pathologic diagnosis was focal cortical dysplasia (n=58). Our results showed that intracranial electroencephalographic monitoring in children provides good surgical outcomes and the level of risk is acceptable. When using this technique strategies such as using as few electrode contacts as possible should be adopted to minimize the risk of intracranial hematoma.