The impact of social determinants of health on utilization of pediatric epilepsy surgery: a systematic review.

OBJECTIVE: A minority of pediatric patients who may benefit from epilepsy surgery receive it. The reasons for this utilization gap are complex and not completely understood. Patient and caregiver social determinants of health (SDOH) may impact which patients undergo surgery and when. The authors conducted a systematic review examining SDOH and surgical intervention in children with drug-resistant epilepsy (DRE). They aimed to understand which factors influenced time to surgical program referral or receipt of epilepsy surgery among children with DRE, as well as identify areas to characterize the SDOH impacting epilepsy surgery in children and guide efforts aimed to promote health equity in epilepsy. METHODS: A systematic review was conducted using the PubMed, Embase, and Scopus databases in January 2022. Studies were analyzed by title and abstract, then full text, to identify all studies examining the impact of SDOH on utilization of epilepsy surgery. Studies meeting inclusion criteria were analyzed for SDOH examined, outcomes, and key findings. Quality was assessed using the Grading of Recommendations Assessment, Development and Evaluation system. RESULTS: Of 4545 resultant articles, 18 were included. Studies examined social, cultural, and environmental factors that contributed to SDOH impacting epilepsy surgery. Patients who underwent surgical evaluation were found to be most commonly White and privately insured and have college-educated caregivers. Five studies found differences in time to referral/surgery or rates of surgery by racial group, with most finding an increased time to referral/surgery or lower rates of surgery for those who were Hispanic and/or non-White. Four studies found that private insurance was associated with higher surgical utilization. Three studies found higher household income was related to surgical utilization. No studies examined biological, psychological, or behavioral factors that contributed to SDOH impacting epilepsy surgery. CONCLUSIONS: The authors conducted a systematic review exploring the impact of SDOH in DRE surgery utilization. They found that race, ethnicity, insurance type, caregiver educational attainment, and household income demonstrate relationships with pediatric epilepsy surgery. Further study is necessary to understand how these factors, and others not identified in this study, contribute to the low rates of utilization of epilepsy surgery and potential target areas for interventions aiming to increase equity in access to epilepsy surgery in children.

Naming assessment in bilinguals for epilepsy surgery-adaptation and standardization of Boston Naming Test in India.

PURPOSE: Naming difficulty is associated with temporal lobe epilepsy and a decline in naming ability is reported following dominant temporal lobe resections. The Boston Naming Test (BNT) is the most frequently used test for assessing naming ability. Evaluating naming ability in bilingual/multilingual populations is a challenge when participants are restricted to responding in one language. The study aimed to adapt and standardize the BNT as a valid clinical tool for evaluating bilingual/multilingual people undergoing epilepsy surgery in urban India. RESULTS: Culture-appropriate adaptations were done, and participants were allowed to respond in any language. Data from 197 participants showed a strong education effect. The adaptation showed strong internal consistency, reliability, construct validity, and high sensitivity to left temporal lobe epilepsy performance. CONCLUSIONS: The adapted version that allowed for flexible use of more than one language is a useful clinical tool for evaluating bilingual people undergoing epilepsy surgery.

Racial disparities in the utilization of invasive neuromodulation devices for the treatment of drug-resistant focal epilepsy.

Racial disparities affect multiple dimensions of epilepsy care including epilepsy surgery. This study aims to further explore these disparities by determining the utilization of invasive neuromodulation devices according to race and ethnicity in a multicenter study of patients living with focal drug-resistant epilepsy (DRE). We performed a post hoc analysis of the Human Epilepsy Project 2 (HEP2) data. HEP2 is a prospective study of patients living with focal DRE involving 10 sites distributed across the United States. There were no statistical differences in the racial distribution of the study population compared to the US population using census data except for patients reporting more than one race. Of 154 patients enrolled in HEP2, 55 (36%) underwent invasive neuromodulation for DRE management at some point in the course of their epilepsy. Of those, 36 (71%) were patients who identified as White. Patients were significantly less likely to have a device if they identified solely as Black/African American than if they did not (odds ratio = .21, 95% confidence interval = .05-.96, p = .03). Invasive neuromodulation for management of DRE is underutilized in the Black/African American population, indicating a new facet of racial disparities in epilepsy care.

Assessment of language lateralization in epilepsy patients using the super-selective Wada test.

BACKGROUND: The classical Wada test (cWada), performed by injecting a short-acting anesthetic through the intracarotid route, helps determine language dominance. In the cWada, adverse effects are observed in 10-30% of trials, hindering accurate assessments. In this study, we assessed the effectiveness of the super-selective Wada test (ssWada), a more selective approach for anesthetic infusion into the middle cerebral artery (MCA). METHODS: We retrospectively examined the data of 17 patients with epilepsy who underwent ssWada via anesthetic injection into one M1 segment of the MCA and at least one contralateral trial. RESULTS: The ssWada identified 12 patients with left language dominance, 3 with right language dominance, and 2 with bilateral language distribution. Nine trials on the language dominant side resulted in global aphasia for patients with left- or right language dominance. Of the 13 trials conducted on the non-dominant language side, 12 revealed intact language function and one resulted in confusion. Among these, the outcomes of global aphasia or no language impairment were confirmed in the contralateral trials. Among the 22 trials of unilateral M1 injections in patients with unilateral language dominance, 21 (95.5%) showed either global aphasia or no language impairment, indicating language dominance. CONCLUSIONS: The ssWada yields clear results, with a high rate of over 90% in determining the language dominant hemisphere with few side effects.

Super-selective Wada test for pre-surgical leg motor function assessment: A case report.

INTRODUCTION: Wada test is well-known to assess lateralization of memory and language functions; however, super-selective Wada (ss-Wada) to evaluate motor leg function is rare. We present a ss-Wada test within the anterior cerebral artery (ACA) to assess the motor function of the leg. METHODS: Retrospective chart review. RESULTS: Comprehensive phase-I/II surgical evaluation revealed an ictal focus around the left post-central gyrus with immediate involvement around the left para-central regions. To avoid potential right leg motor dysfunction with the surgery, the patient underwent a ss-Wada procedure. Angiography revealed bilateral ACAs were supplied by the left A1 segment. Super-selective microcatheter injection of amobarbital into the left ACA was performed to avoid cross-filling the contralateral ACA. The ss-Wada test confirmed no right leg motor impairment. Afterward, a craniotomy with direct cortical stimulation confirmed that the left-sided ictal/peri-ictal zone had no clear leg motor function. The patient underwent disconnection of that region and remained seizure-free at 10-month post-op follow-up without any motor or sensory deficits in the right limbs. CONCLUSION: This case demonstrates the proof of concept for ss-Wada in assessing lower extremity motor function. The ss-Wada procedure accurately predicted no motor deficits in the right leg, consistent with preserved motor function post-surgery.

Societal costs and quality of life analysis in patients undergoing resective epilepsy surgery: A one-year follow-up.

Although effectiveness of Resective Epilepsy Surgery (RES) for patients with drug-resistant epilepsy (DRE) is widely proven, research on the impact of societal costs (SC) is lacking. The aim of this study is to provide both clinical and economic outcomes of RES by offering an overview of treatment effectiveness as well as SC of RES in a cohort of 30 Dutch DRE patients. This project serves as a pilot project to offer an up-to-date model for larger cost-effectiveness studies. Medical consumption, productivity losses, disease-specific and generic health-related quality of life (QoL), and seizure frequency were assessed before and 3-, 6-, and 12-months post-surgery with validated questionnaires. Linear mixed models, ANOVAs, and logistic regressions were performed. SC for the first year after RES entailed €54,376 and decreased over time. Moreover, 50% of patients experienced a clinically important increase in disease-specific QoL and 53% of patients in generic health-related QoL. Lastly, 73% of patients reached seizure freedom 12 months postoperative. Seizure reduction was correlated with increase in disease-specific QoL. Within one year after surgery, RES leads to reduction in SC and improvements in QoL over time. Future research should encompass longer follow-up periods, larger sample size, and a cost-effectiveness analysis with a comparator.

Comprehensive Outcome Assessment and Quality of Life Following Epilepsy Surgery.

BACKGROUND: Seizure freedom without deficits is the primary goal for epilepsy surgery. However, patients with medically refractory epilepsy commonly suffer from many co-morbidities related to mood, cognition, and sleep as well as social problems and resultant stigma. While epilepsy surgery literature does describe quality of life (QOL) and neuropsychological outcomes, there is a paucity of information on various common non-seizure outcomes, especially pertaining to mood, sleep, cognition, and social aspects. The objective of this study was to evaluate the role of various non-seizure parameters on post-epilepsy surgery QOL. METHODS: Consecutive adult patients operated for refractory epilepsy at least 1 year prior to initiation of this study were included and classified as seizure-free (group 1) or non-seizure-free (group 2). QOL was assessed using the QOLIE-31 instrument; patients with a T score less than 40 were categorized as "poor QOL." Non-seizure parameters assessed were cognition, mood disturbances, social improvement, social stigma, and sleep disturbances. Categorization into "good" and "poor" outcome subgroups on each item was carried out by dichotomization of scores. RESULTS: Thirty-seven patients (16 F) [mean age 23.5 ± 5.6 years] were evaluated; 26 were seizure-free (group 1). In this group, impaired memory, lower language scores, depression, not having been employed, not receiving education prior to surgery, and experiencing social stigma were factors significantly associated with poor QOL. In group 2, all patients had poor QOL scores. CONCLUSION: Non-seizure factors related to common epilepsy co-morbidities and social issues are highly prevalent among seizure-free patients reporting poor QOL after epilepsy surgery.

Predictors of referral for long-term EEG monitoring for Medicare beneficiaries with drug-resistant epilepsy.

OBJECTIVE: For people with drug-resistant epilepsy, the use of epilepsy surgery is low despite favorable odds of seizure freedom. To better understand surgery utilization, we explored factors associated with inpatient long-term EEG monitoring (LTM), the first step of the presurgical pathway. METHODS: Using 2001-2018 Medicare files, we identified patients with incident drug-resistant epilepsy using validated criteria of ≥2 distinct antiseizure medication (ASM) prescriptions and ≥1 drug-resistant epilepsy encounter among patients with ≥2 years pre- and ≥1 year post-diagnosis Medicare enrollment. We used multilevel logistic regression to evaluate associations between LTM and patient, provider, and geographic factors. We then analyzed neurologist-diagnosed patients to further evaluate provider/environmental characteristics. RESULTS: Of 12 044 patients with incident drug-resistant epilepsy diagnosis identified, 2% underwent surgery. Most (68%) were diagnosed by a neurologist. In total, 19% underwent LTM near/after drug-resistant epilepsy diagnosis; another 4% only underwent LTM much prior to diagnosis. Patient factors most strongly predicting LTM were age <65 (adjusted odds ratio 1.5 [95% confidence interval 1.3-1.8]), focal epilepsy (1.6 [1.4-1.9]), psychogenic non-epileptic spells diagnosis (1.6 [1.1-2.5]) prior hospitalization (1.7, [1.5-2]), and epilepsy center proximity (1.6 [1.3-1.9]). Additional predictors included female gender, Medicare/Medicaid non-dual eligibility, certain comorbidities, physician specialties, regional neurologist density, and prior LTM. Among neurologist-diagnosed patients, neurologist <10 years from graduation, near an epilepsy center, or epilepsy-specialized increased LTM likelihood (1.5 [1.3-1.9], 2.1 [1.8-2.5], 2.6 [2.1-3.1], respectively). In this model, 37% of variation in LTM completion near/after diagnosis was explained by individual neurologist practice and/or environment rather than measurable patient factors (intraclass correlation coefficient 0.37). SIGNIFICANCE: A small proportion of Medicare beneficiaries with drug-resistant epilepsy completed LTM, a proxy for epilepsy surgery referral. While some patient factors and access measures predicted LTM, non-patient factors explained a sizable proportion of variance in LTM completion. To increase surgery utilization, these data suggest initiatives targeting better support of neurologist referral.

Intraoperative MRI Assessment of the Tissue Damage during Laser Ablation of Hypothalamic Hamartoma.

Laser ablation for treatment of hypothalamic hamartoma (HH) is a minimally invasive and effective technique used to destroy hamartomatous tissue and disconnect it from the functioning brain. Currently, the gold standard to evaluate the amount of tissue being "burned" is the use of heat maps during the ablation procedure. However, these maps have low spatial resolution and can be misleading in terms of extension of the tissue damage. The aim of this study is to use different MRI sequences immediately after each laser ablation and correlate the extension of signal changes with the volume of malacic changes in a long-term follow-up scan. During the laser ablation procedure, we imaged the hypothalamic region with high-resolution axial diffusion-weighted images (DWI) and T2-weighted images (T2WI) after each ablation. At the end of the procedure, we also added a post-contrast T1-weighted image (T1WI) of the same region. We then correlated the product of the maximum diameters on axial showing signal changes (acute oedema on T2WI, DWI restriction rim, DWI hypointense core and post-contrast T1WI rim) with the product of the maximum diameters on axial T2WI of the malacic changes in the follow-up scan, both as a fraction of the total area of the hamartoma. The area of the hypointense core on DWI acquired immediately after the laser ablation statistically correlated better with the final area of encephalomalacia, while the T2WI, hyperintense oedema, DWI rim and T1WI rim of enhancement tended to overestimate the encephalomalacic damage. In conclusion, the use of intraoperative sequences (in particular DWI) during laser ablation can give surgeons valuable information in real time about the effective heating damage on the hamartomatous tissue, with better spatial resolution in comparison to the thermal maps.

Clinical Benefit of Vagus Nerve Stimulation for Epilepsy: Assessment of Randomized Controlled Trials and Prospective Non-Randomized Studies.

We examined the efficacy of vagal nerve stimulation (VNS) for patients suffering from medically intractable epilepsy. Four randomized controlled trials (RCTs - 3 adult RCTs and 1 pediatric RCT) were identified in our comprehensive literature search. Across the 4 studies, high frequency VNS stimulation (frequency >20 Hz) consistently achieved a greater seizure frequency reduction (23.4-33.1%) relative to low frequency VNS stimulation (1 Hz, .6-15.2%). We identified 2 RCTs examining whether the parameters of stimulation influenced seizure control. These studies reported that VNS achieved seizure control comparable to those reported by the first 4 RCTs (22-43% seizure frequency reduction), irrespective of the parameters utilized for VNS stimulation. In terms of VNS associated morbidity, these morbidities were consistently higher in adults who underwent high frequency VNS stimulation (eg dysphonia 37-66%, dyspnea 6-25.3%). However, no such differences were observed in the pediatric population. Moreover, <2% of patients withdrew from the RCTs/prospective studies due to intolerable symptoms. To provide an assessment of how the risks and benefits of VNS impact the patient experience, 1 study assessed the well-being of enrolled patients (as a secondary end point) and found VNS was associated with an overall improvement in well-being. Consistent with this observation, we identified a prospective, non-randomized study that demonstrated improved quality of life for epilepsy patients managed with VNS and best medical practice relative to best medical practice alone. In aggregate, these RCT studies support the efficacy and benefit of VNS as a neuro-modulatory platform in the management of a subset of medically refractory epilepsy patients.

Health care resource utilization and costs before and after epilepsy surgery.

OBJECTIVE: To describe the demographics of epilepsy surgery utilization and its impact on health care resource use. METHODS: Retrospective descriptive study using the MarketScan commercial claims database. We studied children and adults who underwent epilepsy surgery in the USA in the period 2006-2019. Our main outcome was health care resource utilization. RESULTS: Among the 87,368 patients with refractory epilepsy, 2,011 (2.3%) patients underwent resective epilepsy surgery, 188 (0.2%) patients underwent partial or total hemispherectomy, and 183 (0.2%) patients underwent corpus callosotomy. The proportion of patients undergoing epilepsy surgery has barely increased in the period 2006 to 2019. The year of resective epilepsy surgery was associated with high healthcare costs per person-year [median (p25-p75): $140,322 ($88,749-$225,862)], but healthcare costs per person-year substantially decreased in the 5 years after compared to the 5 years before the year of resective epilepsy surgery [$7,691 ($2,738-$22,092) versus $18,750 ($7,361-$47,082), p-value < 0.0001]. This result held in all resective epilepsy surgery subgroups: children, adults, temporal, extratemporal, subdural EEG monitoring, stereoEEG monitoring, and no intracranial monitoring. Similarly, the year of hemispherectomy was associated with high healthcare costs per person-year [$260,983 ($154,791-$453,986)], but healthcare costs per person-year substantially decreased in the 5 years after compared to the 5 years before the year of hemispherectomy [$26,834 ($12,842-$52,627) versus $54,596 ($19,547-$136,412), p-value < 0.0001]. In contrast, the year of corpus callosotomy was associated with high healthcare costs per person-year [$162,399 ($108,150-$253,156)], but healthcare costs per person-year did not substantially decrease in the 5 years after than in the 5 years before the year of corpus callosotomy [$25,464 ($10,764-$69,338) versus $36,221 ($12,841-$85,747), p-value = 0.2142]. CONCLUSION: In privately insured patients in the USA, resective epilepsy surgery and hemispherectomy substantially decrease healthcare utilization in subsequent years. Epilepsy surgery may help contain costs in the field of epilepsy.

Impacto psicosocial del desarrollo científico-técnico en el estudio de la epilepsia

Introducción: Se ha planteado que no existe otra enfermedad asociada a tantos problemas sociales como lo es la epilepsia. Objetivo: Describir el impacto social del desarrollo científico-técnico en el estudio de la epilepsia. Método: Se realizó una revisión narrativa a partir del estudio documental de varias fuentes bibliográficas encontradas en base de datos electrónicas. Los principales criterios de búsqueda fueron: artículos publicados en los últimos 10 años sobre impacto psicosocial del desarrollo científico-técnico en el estudio de la epilepsia. Desarrollo: El efecto sobrenatural atribuido a la epilepsia, con su consecuente repercusión social, es resultado de especulaciones provocadas por siglos de falsas creencias sobre esta enfermedad. El impacto social de la enfermedad es negativo, genera problemas financieros, de aislamiento, de exclusión social y discriminación. Se plantea que la epilepsia tiene gran influencia en todos los niveles de calidad de vida. Las anomalías detectadas por las novedosas técnicas de estudio por neuroimagen en la epilepsia se han relacionado con el deterioro cognitivo, refractariedad de la enfermedad y otros hallazgos que pueden estar relacionados indirectamente con las alteraciones psicosociales de los pacientes. Consideraciones finales: La epilepsia, además del daño orgánico, genera consecuencias psicosociales negativas que limitan el desempeño saludable de los enfermos. En los últimos años los adelantos científico-técnicos han limitado de forma parcial los efectos sociales negativos de la enfermedad con la incorporación de novedosas tecnologías para su estudio y tratamiento.

Introduction: Views has been expressed that there is no disease more linked with social problems than epilepsy. Objective: To describe the social impact of scientific and technological development on the study of epilepsy. Method: A narrative review was carried out supported on the documentary research of several bibliographic sources found in electronic databases. The main search criteria were as follow: articles published in the last 10 years, which had relation with aspects concerning the psychosocial impact of scientific and technological development on the study of epilepsy. Development: The supernatural effect attributes to epilepsy, including its social repercussions, is the result of centuries of speculative theories and false beliefs about this disease. Epilepsy has negative impact on social well-being, causing serious economic problems, isolation, social exclusion and discrimination. Epilepsy is described as a disease with a great influence on all levels of quality of life. The abnormalities detected using novel neuroimaging techniques referred to the presence of cognitive impairment, refractory period and other aspects which may be indirectly related to psychosocial alterations in patients. Final considerations: Epilepsy, in addition to its traumatic effects, has negative psychosocial consequences that affect the healthy performance of patients. In recent years, the scientific and technological advancements have partially limited the negative social effects causes by this disease with the use of new technologies for its study and treatment.

Introdução: Tem sido sugerido que não há outra doença associada a tantos problemas sociais quanto a epilepsia. Objetivo: Descrever o impacto social do desenvolvimento científico-técnico no estudo da epilepsia. Método: Realizou-se revisão narrativa a partir do estudo documental de diversas fontes bibliográficas encontradas em bases de dados eletrônicas. Os principais critérios de busca foram: artigos publicados nos últimos 10 anos sobre o impacto psicossocial do desenvolvimento científico-técnico no estudo da epilepsia. Desenvolvimento: O efeito sobrenatural atribuído à epilepsia, com sua consequente repercussão social, é fruto de especulações causadas por séculos de falsas crenças sobre essa doença. O impacto social da doença é negativo, gera problemas financeiros, isolamento, exclusão social e discriminação. Sugere-se que a epilepsia tenha grande influência em todos os níveis da qualidade de vida. As anormalidades detectadas pelas novas técnicas de estudo de neuroimagem na epilepsia têm sido relacionadas à deterioração cognitiva, refratariedade da doença e outros achados que podem estar indiretamente relacionados às alterações psicossociais dos pacientes. Considerações finais: A epilepsia, além dos danos orgânicos, gera consequências psicossociais negativas que limitam o desempenho saudável dos pacientes. Nos últimos anos, os avanços técnico-científicos limitaram parcialmente os efeitos sociais negativos da doença com a incorporação de novas tecnologias para seu estudo e tratamento.

Beyond Resection: Neuromodulation and Minimally Invasive Epilepsy Surgery.

Epilepsy is a common neurological disease impacting both patients and healthcare systems. Approximately one third of patients have drug-resistant epilepsy (DRE) and are candidates for surgical options. However, only a small percentage undergo surgical treatment due to factors such as patient misconception/fear of surgery, healthcare disparities in epilepsy care, complex presurgical evaluation, primary care knowledge gap, and lack of systemic structures to allow effective coordination between referring physician and surgical epilepsy centers. Resective surgical treatments are superior to medication management for DRE patients in terms of seizure outcomes but may be less palatable to patients. There have been major advancements in minimally invasive surgeries (MIS) and neuromodulation techniques that may allay these concerns. Both epilepsy MIS and neuromodulation have shown promising seizure outcomes while minimizing complications. Minimally invasive methods include Laser Interstitial Thermal Therapy (LITT), RadioFrequency Ablation (RFA), Stereotactic RadioSurgery (SRS). Neuromodulation methods, which are more palliative, include Vagus Nerve Stimulation (VNS), Deep Brain Stimulation (DBS), and Responsive Neurostimulation System (RNS). This review will discuss the role of these techniques in varied epilepsy subtypes, their effectiveness in improving seizure control, and adverse outcomes.

Stereoelectroencephalography in the preoperative assessment of patients with refractory focal epilepsy: experience at an epilepsy centre.

OBJECTIVE: Stereoelectroencephalography (SEEG) is a technique for preoperative evaluation of patients with difficult-to-localise refractory focal epilepsy (DLRFE), enabling the study of deep cortical structures. The procedure, which is increasingly used in international epilepsy centres, has not been fully developed in Spain. We describe our experience with SEEG in the preoperative evaluation of DLRFE. MATERIAL AND METHODS: In the last 8 years, 71 patients with DLRFE were evaluated with SEEG in our epilepsy centre. We prospectively analysed our results in terms of localisation of the epileptogenic zone (EZ), surgical outcomes, and complications associated with the procedure. RESULTS: The median age of the sample was 30 years (range, 4-59 years); 27 patients (38%) were women. Forty-five patients (63.4%) showed no abnormalities on brain MR images. A total of 627 electrodes were implanted (median, 9 electrodes per patient; range, 1-17), and 50% of implantations were multilobar. The EZ was identified in 64 patients (90.1%), and was extratemporal or temporal plus in 66% of the cases. Follow-up was over one year in 55 of the 61 patients undergoing surgery: in the last year of follow-up, 58.2% were seizure-free (Engel Epilepsy Surgery Outcome Scale class I) and 76.4% had good outcomes (Engel I-II). Three patients (4.2%) presented brain haemorrhages. CONCLUSION: SEEG enables localisation of the EZ in patients in whom this was previously impossible, offering better surgical outcomes than other invasive techniques while having a relatively low rate of complications.

Assessment of intraoperative diffusion EPI distortion and its impact on estimation of supratentorial white matter tract positions in pediatric epilepsy surgery.

The effectiveness of correcting diffusion Echo Planar Imaging (EPI) distortion and its impact on tractography reconstruction have not been adequately investigated in the intraoperative MRI setting, particularly for High Angular Resolution Diffusion Imaging (HARDI) acquisition. In this study, we evaluated the effectiveness of EPI distortion correction using 27 legacy intraoperative HARDI datasets over two consecutive surgical time points, acquired without reverse phase-encoded data, from 17 children who underwent epilepsy surgery at our institution. The data was processed with EPI distortion correction using the Synb0-Disco technique (Schilling et al., 2019) and without distortion correction. The corrected and uncorrected b0 diffusion-weighted images (DWI) were first compared visually. The mutual information indices between the original T1-weighted images and the fractional anisotropy images derived from corrected and uncorrected DWI were used to quantify the effect of distortion correction. Sixty-four white matter tracts were segmented from each dataset, using a deep-learning based automated tractography algorithm for the purpose of a standardized and unbiased evaluation. Displacement was calculated between tracts generated before and after distortion correction. The tracts were grouped based on their principal morphological orientations to investigate whether the effects of EPI distortion vary with tract orientation. Group differences in tract distortion were investigated both globally, and regionally with respect to proximity to the resecting lesion in the operative hemisphere. Qualitatively, we observed notable improvement in the corrected diffusion images, over the typically affected brain regions near skull-base air sinuses, and correction of additional distortion unique to intraoperative open cranium images, particularly over the resection site. This improvement was supported quantitatively, as mutual information indices between the FA and T1-weighted images were significantly greater after the correction, compared to before the correction. Maximum tract displacement between the corrected and uncorrected data, was in the range of 7.5 to 10.0 mm, a magnitude that would challenge the safety resection margin typically tolerated for tractography-informed surgical guidance. This was particularly relevant for tracts oriented partially or fully in-line with the acquired diffusion phase-encoded direction. Portions of these tracts passing close to the resection site demonstrated significantly greater magnitude of displacement, compared to portions of tracts remote from the resection site in the operative hemisphere. Our findings have direct clinical implication on the accuracy of intraoperative tractography-informed image guidance and emphasize the need to develop a distortion correction technique with feasible intraoperative processing time.

Uses and abuses of the neuropsychological assessment in the presurgical evaluation of epilepsy surgery candidates.

Recent guidelines from the International League Against Epilepsy (ILAE) delineating the role of the neuropsychologist in the assessment of epilepsy surgery patients stress the collaborative contribution neuropsychologists should make to seizure characterization, lateralization and localization in the pre-surgical setting. The role they should play in the comprehensive counselling of surgical candidates, including exploration of the patient's expectations of surgical treatment is also mandated. In this paper we present two contrasting case studies which illustrate the importance of these roles and the impact they can have on patient outcomes. In Case A we describe the patient journey of a 69-year-old women with left hippocampal sclerosis and concordant neurophysiology and seizure semiology. We present the series of discussions and decisions which led her to reject the surgical option following a detailed exploration of her motivations for surgery and the likely cognitive consequences of the procedure. In Case B we describe the series of errors and omissions which led to the failure of a clinical team to correctly interpret and integrate neuropsychological findings into the larger clinical picture of a 19-year-old woman with a seven year history of seizures. These errors ultimately culminated in the patient undergoing a right temporal lobe resection to treat psychogenic nonepileptic seizures (PNES). The extent of integration of the data from the clinical neuropsychological assessment in the full presurgical evaluation was critical in determining the outcomes in both of these cases. Surgery did not solve Case B's problems and left her with the lifelong cognitive vulnerabilities that are associated with unilateral temporal lobe resection. In contrast, Case A was a good surgical candidate, but comprehensive integration of the neuropsychological findings into the larger clinical picture established that surgery was not the best solution to the problem she wished to solve.

Single-center cost comparison analysis of stereoelectroencephalography with subdural grid and strip implantation.

OBJECTIVE: Use of invasive stereoelectroencephalography (SEEG) has gained traction recently. However, scant research has investigated the costs and resource utilization of SEEG compared with subdural grid (SDG)-based techniques in pediatric patients. Here, the authors have presented a retrospective analysis of charges associated with SEEG and SDG monitoring at a single institution. METHODS: The authors performed a retrospective case series analysis of pediatric patients with similar characteristics in terms of age, sex, seizure etiology, and epilepsy treatment strategy who underwent SEEG or SDG monitoring and subsequent craniotomy for resection of epileptogenic focus at St. Louis Children Hospital, St. Louis, Missouri, between 2013 and 2020. Financial data, including hospital charges, supplies, and professional fees (i.e., those related to anesthesia, neurology, neurosurgery, and critical care), were adjusted for inflation to 2020 US dollars. RESULTS: The authors identified 18 patients (9 underwent SEEG and 9 underwent SDG) with similar characteristics in terms of age (mean [range] 13.6 [1.9-21.8] years for SDG patients vs 11.9 [2.4-19.6] years for SEEG patients, p = 0.607), sex (4 females underwent SDG vs 6 females underwent SEEG, p = 0.637), and presence of lesion (5 patients with a lesion underwent SDG vs 8 underwent SEEG, p = 0.294). All patients underwent subsequent craniotomy for resection of epileptogenic focus. SEEG patients were more likely to have a history of status epilepticus (p = 0.029). Across 1 hospitalization for each SDG patient and 2 hospitalizations for each SEEG patient, SEEG patients had a significantly shorter mean operating room time (288 vs 356 minutes, p = 0.015), mean length of stay in the ICU (1.0 vs 2.1 days, p < 0.001), and tended to have a shorter overall length of stay in the hospital (8.4 vs 10.6 days, p = 0.086). Both groups underwent invasive monitoring for similar lengths of time (5.2 days for SEEG patients vs 6.4 days for SDG patients, p = 0.257). Time to treatment from the initial invasive monitoring evaluation was significantly longer in SEEG patients (64.6 vs 6.4 days, p < 0.001). Neither group underwent readmission within the first 30 days after hospital discharge. Seizure outcomes and complication rates were similar. After adjustment for inflation, the average total perioperative charges were $104,442 for SDG and $106,291 for SEEG (p = 0.800). CONCLUSIONS: Even though 2 hospitalizations were required for SEEG and 1 hospitalization was required for SDG monitoring, patients who underwent SEEG had a significantly shorter average length of stay in the ICU and operating room time. Surgical morbidity and outcomes were similar. Total perioperative charges for invasive monitoring and resection were approximately 2% higher for SEEG patients when corrected for inflation, but this difference was not statistically significant.

One-year cost-effectiveness of callosotomy vs vagus nerve stimulation for drug-resistant seizures in Lennox-Gastaut Syndrome: A decision analytic model.

OBJECTIVE: Palliative epilepsy surgery via corpus callosotomy (CC) or vagus nerve stimulation (VNS) is commonly employed for drug-resistant seizures in Lennox-Gastaut Syndrome (LGS). VNS is less effective at reducing seizures but has fewer adverse events, CC is more effective for seizure control, particularly atonic seizures, but can be associated with serious adverse events, and yet their relative cost-effectiveness remains unknown. METHODS: To determine which option is most cost-effective, a decision analytic model was developed to evaluate the risks and benefits of CC and VNS at 1 year based on costs in the United States. Our primary outcome measure was positive seizure outcomes, defined as >50% seizure reduction without procedural complications. RESULTS: CC had a 15% greater likelihood of a positive seizure outcome, but per patient costs were $68 147 more than VNS, or $451 952 per positive seizure outcome gained. One-way sensitivity analyses demonstrate that probabilities of seizure freedom or reduction by VNS or CC and CC cost were most influential on results. When considering atonic seizures, CC had a 27% greater positive outcome likelihood than VNS, the same incremental cost, and cost $250 556 per positive seizure outcome gained. SIGNIFICANCE: This exploratory model suggests that VNS is more cost-effective relative to CC at 1 year.

Scalp-HFO indexes are biomarkers for the lateralization and localization of the epileptogenic zone in preoperative assessment.

During the noninvasive evaluation phase for refractory epilepsy, the localization of the epileptogenic zone (EZ) is essential for the surgical protocols. Confirmation of laterality is required when the preoperative evaluation limits the EZ to bilateral anterior temporal lobes or bilateral frontal lobes. High-frequency oscillations (HFOs) are considered to be promising biological markers for the EZ. However, a large number of studies on HFOs stem from intracranial research. There were few quantitative measures for scalp HFOs, so we proposed a new method to quantify and analyze scalp HFOs. This method was called the "scalp-HFO index" (HI) and calculated in both the EZ and non-EZ. The calculation was based on the numbers and spectral power of scalp HFOs automatically detected. We labeled the brain lobes involved in the EZ as regions of interest (ROIs). The HIs based on the ripple numbers (n-HI) and spectral power (s-HI) were significantly higher in the ROI than in the contra-ROI (P = 0.012, P = 0.003), indicating that HIs contributed to the lateralization of EZ. The sensitivity and specificity of n-HI for the localization of the EZ were 90% and 79.58%, respectively, suggesting that n-HI was valuable in localizing the EZ. HI may contribute to the implantation strategy of invasive electrodes. However, few scalp HFOs were recorded when the EZ was located in the medial cortex region.NEW & NOTEWORTHY We proposed the scalp-high-frequency oscillation (HFO) index (HI) as a quantitative assessment method for scalp HFOs to locate the epileptogenic zone (EZ). Our results showed that the HI in regions of interest (ROIs) was significantly higher than in contra-ROIs. Sensitivity and specificity of HI based on ripple rates (n-HI) for EZ localization were 90% and 79.58%, respectively. If the n-HI of the brain region was >1.35, it was more likely to be an epileptogenic region. Clinical application of HIs as an indicator may facilitate localization of the EZ.