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ILAE Commission Report. Proposal for a new classification of outcome with respect to epileptic seizures following epilepsy surgery
Epilepsia
... A pproximately 1/3 of patients with epilepsy are refractory to medications and should be evaluated for epilepsy surgery. 1,2 Surgical treatment of the epileptogenic zone (EZ) may be a curative procedure, yet despite many advances in diagnostic and surgical procedures in recent decades, 30% to 60% of patients do not become seizure free. 1,[3][4][5] Localizing cerebral epileptiform activity is paramount to identifying the EZ and determining the patient's ultimate surgical treatment. ...
... 1,2 Surgical treatment of the epileptogenic zone (EZ) may be a curative procedure, yet despite many advances in diagnostic and surgical procedures in recent decades, 30% to 60% of patients do not become seizure free. 1,[3][4][5] Localizing cerebral epileptiform activity is paramount to identifying the EZ and determining the patient's ultimate surgical treatment. Inaccurate localization may lead to surgical failure, placing the patient at risk of complications and deficits without the benefit of becoming seizure-free. ...
Introduction
EEG source localization is an established technique for localizing scalp EEG in medically refractory epilepsy but has not been adequately studied with intracranial EEG (iEEG). Differences in sensor location and spatial sampling may affect the accuracy of EEG source localization with iEEG. Corticocortical evoked potentials can be used to evaluate EEG source localization algorithms for iEEG given the known source location.
Methods
We recorded 205 sets of corticocortical evoked potentials using low-frequency single-pulse electrical stimulation in four patients with iEEG. Averaged corticocortical evoked potentials were analyzed using 11 distributed source algorithms and compared using the Wilcoxon signed-rank test ( P < 0.05). We measured the localization error from stimulated electrodes and the spatial dispersion of each solution.
Results
Minimum norm, standard low-resolution electromagnetic tomography (sLORETA), LP Norm, sLORETA-weighted accurate minimum norm (SWARM), exact LORETA (eLORETA), standardized weighted LORETA (swLORETA), and standardized shrinking LORETA-FOCUSS (ssLOFO) had the least localization error (13.3–15.7 mm) and were superior to focal underdetermined system solver (FOCUSS), logistic autoregressive average (LAURA, and LORETA, 17.9–21.7, P < 0.001). The FOCUSS solution had the smallest spatial dispersion (7.4 mm), followed by minimum norm, L1 norm, LP norm, and SWARM (20.8–28.3 mm). Gray matter stimulations had less localization error than white matter (median differences 3.1–6.1 mm) across all algorithms except SWARM, LORETA, and logistic autoregressive average. A multivariate linear regression showed that distance from the source to sensors and gray/white matter stimulation had a significant effect on localization error for some algorithms but not SWARM, minimum norm, focal underdetermined system solver, logistic autoregressive average, and LORETA.
Conclusions
Our study demonstrated that minimum norm, L1 norm, LP norm, and SWARM localize iEEG corticocortical evoked potentials well with lower localization error and spatial dispersion. Larger studies are needed to confirm these findings.
... The effectiveness of treatment for stroke-like episodes was determined by comparing the mean annual frequency of episodes before and after treatment. Seizure control over the preceding year was classified into three categories relative to baseline: complete control (absence of seizures), partial control (≥ 50% reduction in seizures), and no control (no change or < 50% reduction in seizures) [17]. Both complete and partial control were considered effective. ...
Objective
The aim was to summarise the clinical characteristics of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS), evaluate patient survival status, and identify prognostic factors.
Methods
This retrospective study enrolled 150 children with MELAS from 07/2004 to 07/2023. The patients were followed up for a median of 3.37 years (IQR: 2.07–6.16 years). Disease burden was assessed using the Newcastle Pediatric Mitochondrial Disease Scale (NPMDS), and Spearman’s correlation coefficient was used to analyse factors affecting disease severity. The Kaplan–Meier and Cox proportional methods were used for survival analysis.
Results
Overall, 150 patients (73 male) were enrolled, of whom 118 were followed up and 22 died. The mean age at onset was 8.2 years (0.4–15.3), and stroke-like episodes were the most common initial symptoms (54%). Among the surviving patients, 78 completed the NPMDS (mean score: 23.6 ± 6.7 points), and 71.8% (56/78) had moderate-to-severe disease (NPMDS score ≥ 15 points). The NPMDS score was positively correlated with disease duration (r = 0.41, P < 0.001) and negatively correlated with age at onset (r = −0.26, P < 0.01). Among 48 patients who received long-term oral L-arginine and anti-seizure medications (ASMs), 56.3% (27/48) experienced reductions in seizures and stroke-like episodes. The 10- and 15-year survival rates were 65.3% and 34.5%, respectively. Muscle weakness was an independent risk factor for death (HR = 4.83, 95% CI 1.32–17.68; P = 0.017).
Conclusions
This study had the largest cohort and longest follow-up of pediatric MELAS. Early onset was associated with severe disease, while muscle weakness was associated with a worse prognosis. Early identification and effective management of stroke-like episodes and seizures are crucial to reduce the disease burden.
... 24,25 Developing more consistent criteria for assessing seizure freedom outcomes during ASM treatment, such as the Engel-and ILAE-proposed classifications of epilepsy surgery outcomes, may be helpful. 38,39 Patient compliance is another important consideration in the assessment of seizure freedom. ASMs with oncedaily dosing and longer half-lives may be preferable in this context. ...
Seizure freedom is an important therapeutic goal for people with epilepsy and is associated with improved quality of life and reduced morbidity and mortality. Yet despite the use of multiple antiseizure medications (ASMs; either as monotherapy or in combination), seizures persist in approximately one third of patients. Third‐generation ASMs, such as lacosamide, eslicarbazepine, perampanel, and brivaracetam, have demonstrated good efficacy in terms of reductions in the frequency of focal seizures. The newest ASM, cenobamate, which is indicated for the treatment of focal seizures in adults, has demonstrated notable rates of seizure freedom for some patients with drug‐resistant epilepsy. In long‐term, open‐label clinical studies of adjunctive cenobamate, between 18.4% and 36.3% of patients achieved seizure freedom for a consecutive ≥12‐month duration, and 1‐year retention rates ranged from 73% to 83%. This article reviews some of the potential treatment barriers encountered during the medication management of patients with epilepsy that may impede the use and optimization of newer ASMs like cenobamate. These include treatment complacency, inadequate trial of new adjunctive therapies (“last in, first out”), pitfalls of rational polytherapy, and restricting the use of newer drugs. Although treatment must always be tailored to the specific patient, clinicians should consider the potential benefits of newer therapies and continue to reassess and optimize ASM treatment to achieve the best outcomes for their patients.
... In addition to semiology, presurgical evaluation involves multimodal brain imaging tools such as electroencephalography (EEG), stereoelectroencephalography (SEEG), magnetoencephalography (MEG), magnetic resonance imaging (MRI), and functional MRI (fMRI) [7,8]. To determine the ground truth of EZs, the post-surgical outcome information (whether or not the patient achieved seizure freedom) is used to validate the resected brain regions, with seizurefree status determined according to the International League Against Epilepsy (ILAE) criteria "Class I: Completely seizure-free; no auras" [9] or Engel's classification "Class I: Seizure free or no more than a few early, non-disabling seizures" [10]. ...
Background:
For patients with drug-resistant focal epilepsy (DRE), surgical resection of the
epileptogenic zone (EZ) is an effective treatment to control seizures. Accurate
localization of the EZ is crucial and is typically achieved through comprehensive
presurgical approaches such as seizure semiology interpretation,
electroencephalography (EEG), magnetic resonance imaging (MRI), and intracranial
EEG (iEEG). However, interpreting seizure semiology poses challenges because it
relies heavily on expert knowledge and is often based on inconsistent and incoherent
descriptions, leading to variability and potential limitations in presurgical evaluation.
To overcome these challenges, advanced technologies like large language models
(LLMs)—with ChatGPT being a notable example—offer valuable tools for analyzing
complex textual information, making them well-suited to interpret detailed seizure
semiology descriptions and assist in accurately localizing the EZ.
... Ambulance use was classified as planned use or emergency use. Seizure frequency after surgery was classified according to the International League Against Epilepsy (ILAE) outcome scale, where seizure freedom was determined as class 1 27 . Additional data were collected using self-reported standardized questionnaires three months before surgery, and 3-, 6-, 12-, and 24-months post-operative. ...
Background
In contrast to clinical effectiveness of resective epilepsy surgery (RES) for patients with drug-resistant epilepsy, societal costs of RES is still unclear. The aim of this study was to report on total societal costs up until two years after surgery and analyse the trend of post-surgical costs over time. Secondary objectives included assessing quality of life (QoL) changes and identifying determinants of post-surgical costs.
Methods
Data were derived from the patients’ entire medical history based on hospital files and accompanied by validated questionnaires before and 3-, 6-, 12-, and 24-months post-surgery to additionally include medical consumption outside of the hospital, productivity losses and gains, and QoL. To explore the trend of post-surgical costs over time and identify determinants of post-surgical costs, linear mixed effects and linear regression models were performed.
Results
The study included 44 patients. Mean complete costs from diagnostics and treatment strategies in the period before referral for pre-surgical evaluation up until two years after RES were €121,856 (Interquartile range = €76,058−€137,027). Post-surgical costs significantly decreased 12 months (mean 3-month difference = €−6,675, p = 0.000) and 24 months (mean 3-month difference = €−7,690, p = 0.000) after surgery compared to 3 months before surgery. Higher post-surgical costs were associated with a clinically relevant increase in disease-specific QoL after RES (p = 0.000), previous ketogenic diet (p = 0.005), RES in the left hemisphere (p = 0.014), previous RES (p = 0.007), and higher diagnostics and treatment strategies costs before referral for pre-surgical evaluation (p = 0.021). For disease-specific and generic QoL, 20 (45%) patients reached a clinically relevant QoL increase two years after surgery compared to before RES.
Conclusion
In conclusion, RES leads to significant reduction in costs 2 years post-surgery. History of RES and ketogenic diet, clinically relevant disease-specific QoL increase, surgery in the left hemisphere, and higher costs of diagnostics and treatment strategies before referral for pre-surgical evaluation were significant determinants for higher post-surgical costs after RES.
... Postoperative cerebrospinal fluid leakage will be defined as CSC if further surgical/ Fig. 5 Graphical overview of the ILAE classification system for assessing postoperative seizure outcome. Scheme adapted from Wieser et al. [68]. ILAE, International League Against Epilepsy; yr, year interventional therapy (surgical wound examination, transient insertion of a lumbar drainage system and/ or surgical insertion of a permanent shunt system) is required. ...
Background
The discovery of cellular tumor networks in glioblastoma, with routes of malignant communication extending far beyond the detectable tumor margins, has highlighted the potential of supramarginal resection strategies. Retrospective data suggest that these approaches may improve long-term disease control. However, their application is limited by the proximity of critical brain regions and vasculature, posing challenges for validation in randomized trials. Anterior temporal lobectomy (ATL) is a standardized surgical procedure commonly performed in patients with pharmacoresistant temporal lobe epilepsy. Translating the ATL approach from epilepsy surgery to the neuro-oncological field may provide a model for investigating supramarginal resection in glioblastomas located in the anterior temporal lobe.
Methods
The ATLAS/NOA-29 trial is a prospective, multicenter, multinational, phase III randomized controlled trial designed to compare ATL with standard gross-total resection (GTR) in patients with newly-diagnosed anterior temporal lobe glioblastoma. The primary endpoint is overall survival (OS), with superiority defined by significant improvements in OS and non-inferiority in the co-primary endpoint, quality of life (QoL; “global health” domain of the European organization for research and treatment of cancer (EORTC) QLQ-C30 questionnaire). Secondary endpoints include progression-free survival (PFS), seizure outcomes, neurocognitive performance, and the longitudinal assessment of six selected domains from the EORTC QLQ-C30 and BN20 questionnaires. Randomization will be performed intraoperatively upon receipt of the fresh frozen section result. A total of 178 patients will be randomized in a 1:1 ratio over a 3-year recruitment period and followed-up for a minimum of 3 years. The trial will be supervised by a Data Safety Monitoring Board, with an interim safety analysis planned after the recruitment of the 57th patient to assess potential differences in modified Rankin Scale (mRS) scores between the treatment arms 6 months after resection. Assuming a median improvement in OS from 17 to 27.5 months, the trial is powered at > 80% to detect OS differences with a two-sided log-rank test at a 5% significance level.
Discussion
The ATLAS/NOA-29 trial aims to determine whether ATL provides superior outcomes at equal patients’ Qol compared to GTR in anterior temporal lobe glioblastoma, potentially establishing ATL as the surgical approach of choice for isolated temporal glioblastoma and redefining the standard of care for this patient population.
Trial registration
German Clinical Trials Register (DRKS00035314), registered on October 18, 2024.
... Specifically, the identification of HFOs using scalp EEGs is of great interest clinically, given the accessibility of this method for epilepsy surgery workup (66,(68)(69)(70)(71)(72)(73). Another novel consideration is using source imaging or localization to analyze HFOs. ...
Introduction
This study investigated low-density scalp electrical source imaging of the ictal onset zone and interictal spike ripple high-frequency oscillation networks using source coherence maps in the pediatric epilepsy surgical workup. Intracranial monitoring, the gold standard for determining epileptogenic zones, has limited spatial sampling. Source coherence analysis presents a promising new non-invasive technique.
Methods
This was a retrospective review of 12 patients who underwent focal resections. Source coherence maps were generated using standardized low-resolution electromagnetic tomography and concordance to resection margins was assessed, noting outcomes at 3 years post-surgery.
Results
Ictal source coherence maps were performed in 7/12 patients. Six of seven included the surgical resection. Five of seven cases were seizure free post-resection. Interictal spike ripple electrical source imaging and interictal spike ripple high-frequency oscillation networks using source coherence maps were performed for three cases, with two of three included in the resection and all three were seizure free.
Discussion
These findings may provide proof of principle supporting low-density scalp electrical source imaging of the ictal onset zone and spike ripple network using source coherence maps. This promising method is complementary to ictal and interictal electrical source imaging in the pediatric epilepsy surgical workup, guiding electrode placement for intracranial monitoring to identify the epileptogenic zone.
... Surgical outcome was recorded using the International League Against Epilepsy (ILAE) classification system. 42 Patients were classified as "temporal" if only lateral temporal cortex and/or hippocampus had interictal and/or ictal epileptiform abnormalities. Classification as "temporal plus epilepsy" occurred if the patient had the above as well as extratemporal interictal and/or ictal epileptiform abnormalities. ...
Objective
The most common medically resistant epilepsy (MRE) involves the temporal lobe (TLE), and children designated as temporal plus epilepsy (TLE+) have a five‐times increased risk of postoperative surgical failure. This retrospective, blinded, cross‐sectional study aimed to correlate visual and computational analyses of magnetoencephalography (MEG) virtual sensor waveforms with surgical outcome and epilepsy classification (TLE and TLE+).
Methods
Patients with MRE who underwent MEG and iEEG monitoring and had at least 1 year of postsurgical follow‐up were included in this retrospective analysis. User‐defined virtual sensor (UDvs) beamforming was completed with virtual sensors placed manually and symmetrically in the bilateral amygdalohippocampi, inferior/middle/superior temporal gyri, insula, suprasylvian operculum, orbitofrontal cortex, and temporoparieto‐occipital junction. Additionally, MEG effective connectivity was computed and quantified using eigenvector centrality (EC) to identify hub regions. More conventional MEG methods (equivalent current dipole [ECD], standardized low‐resolution brain electromagnetic tomography, synthetic aperture magnetometry beamformer), UDvs beamformer, and EC hubs were compared to iEEG.
Results
Eighty patients (38 female, 42 male) with MRE (mean age = 11.3 ± 6.2 years, range = 1.0–31.5) were identified and included. Twenty‐five patients (31.3%) were classified as TLE, whereas 55 (68.8%) were TLE+. When modeling the association between MEG method, iEEG, and postoperative surgical outcome (odds of a worse [International League Against Epilepsy (ILAE) class > 2] outcome), a significant result was seen only for UDvs beamformer (odds ratio [OR] = 1.22, 95% confidence interval [CI] = 1.01–1.48). Likewise, when the relationship between MEG method, iEEG, and classification (TLE and TLE+) was modeled, only UDvs beamformer had a significant association (OR = 1.47, 95% CI = 1.13–1.92). When modeling the association between EC hub location and resection/ablation to postoperative surgical outcome (odds of a good [ILAE 1–2] outcome), a significant association was seen (OR = 1.22, 95% CI = 1.05–1.43).
Significance
This study demonstrates a concordance between UDvs beamforming and iEEG that is related to both postsurgical seizure outcome and presurgical classification of epilepsy (TLE and TLE+). UDvs beamforming could be a complementary approach to the well‐established ECD, improving invasive electrode and surgical resection planning for patients undergoing epilepsy surgery evaluations and treatments.
... 25 The age at epilepsy onset in our cohort was highly variable, and these results are concordant with the findings reported by Yao et al. 43 and Guerrini and Barba. 44 None of our patients exhibited neonatal seizures or epilepsy onset in the first 2 months of life; this is comparable to MUHSEC and differs from extensive FCD type 2. 40 Most patients in our study experienced daily seizures, similar to patients with MUHSEC; however, some patients experienced weekly or monthly seizures, similar to patients in a recent study. 22 The median duration of epilepsy in our study was 3.4 years, which is slightly below the duration reported in a large European multicenter epilepsy surgery series. ...
Objective
We comprehensively characterized a large pediatric cohort with focal cortical dysplasia (FCD) type 1 to expand the phenotypic spectrum and to identify predictors of postsurgical outcomes.
Methods
We included pediatric patients with histopathological diagnosis of isolated FCD type 1 and at least 1 year of postsurgical follow‐up. We systematically reanalyzed clinical, electrophysiological, and radiological features. The results of this reanalysis served as independent variables for subsequent statistical analyses of outcome predictors.
Results
All children (N = 31) had drug‐resistant epilepsy with varying impacts on neurodevelopment and cognition (presurgical intelligence quotient [IQ]/developmental quotient scores = 32–106). Low presurgical IQ was associated with abnormal slow background electroencephalographic (EEG) activity and disrupted sleep architecture. Scalp EEG showed predominantly multiregional and often bilateral epileptiform activity. Advanced epilepsy magnetic resonance imaging (MRI) protocols identified FCD‐specific features in 74.2% of patients (23/31), 17 of whom were initially evaluated as MRI‐negative. In six of eight MRI‐negative cases, fluorodeoxyglucose–positron emission tomography (PET) and subtraction ictal single photon emission computed tomography coregistered to MRI helped localize the dysplastic cortex. Sixteen patients (51.6%) underwent invasive EEG. By the last follow‐up (median = 5 years, interquartile range = 3.3–9 years), seizure freedom was achieved in 71% of patients (22/31), including seven of eight MRI‐negative patients. Antiseizure medications were reduced in 21 patients, with complete withdrawal in six. Seizure outcome was predicted by a combination of the following descriptors: age at epilepsy onset, epilepsy duration, long‐term invasive EEG, and specific MRI and PET findings.
Significance
This study highlights the broad phenotypic spectrum of FCD type 1, which spans far beyond the narrow descriptions of previous studies. The applied multilayered presurgical approach helped localize the epileptogenic zone in many previously nonlesional cases, resulting in improved postsurgical seizure outcomes, which are more favorable than previously reported for FCD type 1 patients.
... When callosotomies were done in two phases, the preoperative seizure frequency was taken as before the rst surgery, and the postoperative follow-up was taken after completion of the total CC. The postoperative seizure outcomes were graded using the Engel and ILAE classi cations [30,31]. Patients with postoperative ILAE classes 1 to 4, with more than a 50% decrease in seizure frequency, were termed "responders" to callosotomy. ...
Objective Corpus callosotomy (CC) is a commonly indicated palliative surgery for Drug-Resistant Epilepsy (DRE). While younger age at the time of surgery is a well-established positive prognostic factor, there is limited evidence on long-term outcomes in adult patients with DRE. A study that evaluates seizure control at various follow-up points is necessary to better understand the outcomes of CC. Methods In this retrospective longitudinal cohort we included adult CC patients operated by our institution’s epilepsy surgery service between 1993 and 2023. We compiled epilepsy etiology, preoperative seizure frequency, and postoperative seizure outcomes at < 1-year follow-up, 1–3 years follow-up, and > 3 years of follow-up. Our outcomes were seizure freedom and response rate (50% frequency decrease from preoperative). Results We analyzed data from 63 patients. The most common indication for CC was DRE due to Lennox-Gastaut Syndrome. Median seizure frequency had a significant decrease from preoperative (70 seizures per month [spm], IQR = 16–210) to the 1-year follow-up (4 spm, IQR = 0–20, p = < 0.0001), 1–3 years follow-up (8 spm, IQR = 1–30, p = < 0.0001), and > 3 years of follow-up (7 spm, IQR = 2.25-30, p = < 0.0001). Seizure freedom at one year postoperative decreased from 25.4–9.7% at 1–3 years (p = 0.032), while the overall response rate of our sample remained consistent, being 81% at 1-year follow-up and 70% at the long-term follow-up (p = 0.20). Conclusion We identified that CC effectively decreases seizure frequency in adult patients with DRE. The reduction of seizure frequency after CC remained consistent after the first postoperative year. Prospective clinical trials are needed to better understand the long-term outcomes of CC in adults.
... ) I per cent (%) = (I /n(E)) × 100 (11) Finally, the results were categorized according to the 1-year follow-up surgical outcome. Surgical outcome was collected according to the ILAE seizure outcome classification [17]. Patients were classified into two cases: (1) seizure free after surgery, and (2) seizure not free after surgery. ...
Electroencephalography (EEG) based source localization (ESL) is a useful method to localize the epileptogenic zone in epilepsy surgery. However, previous techniques only perform 3-dimensional (3D) reconstruction, and do not conduct delineation on the cortex surface as a resection guidance, and there is very little data on intracranial EEG and pediatric cases. This study proposes an Intracranial Disease-region Composite-interpretation (IDC) EEG-based source localization (ESL) scheme that uses 3D extended reality (XR) edge computing to enhance visualization and comprehensive interpretation of intracranial EEG-based source localization (iESL) for patients with pediatric epilepsy. The proposed IDC-ESL method was effective in predicting the surgical outcome in patients with focal epilepsy, which can be effectively used for epilepsy surgery. Seizure freedom was clearly associated with complete resection of combined EEG features of interictal spike, high-frequency oscillation (HFO), and seizure onset zone (SOZ), and it had the highest significance in localizing the epileptogenic zone. However, for patients with Lennox-Gastaut syndrome (LGS), IDC-ESL was not performed effectively because of a deeply seated lesion and multifocal abnormalities. It could only roughly estimate the affected area, mainly because of insular involvement. Cautious interpretation based on intraoperative electrocorticography (ECoG) is required for accurate insular resection, particularly for LGS cases.
... Full patient details can be found in Table S11, a summary is given in Table 1. Patient outcomes were defined at 12 months postoperatively, according to the ILAE classification of surgical outcomes (Wieser et al., 2001) and separated into two groups. Group 1 includes patients who were completely seizure free (ILAE 1), and group 2 incorporates all other possibilities (ILAE 2-6). ...
Temporal lobe surgical resection brings seizure remission in up to 80% of patients, with long-term complete seizure freedom in 41%. However, it is unclear how surgery impacts on the structural white matter network, and how the network changes relate to seizure outcome. We used white matter fibre tractography on preoperative diffusion MRI to generate a structural white matter network, and postoperative T1-weighted MRI to retrospectively infer the impact of surgical resection on this network. We then applied graph theory and machine learning to investigate the properties of change between the preoperative and predicted postoperative networks. Temporal lobe surgery had a modest impact on global network efficiency, despite the disruption caused. This was due to alternative shortest paths in the network leading to widespread increases in betweenness centrality post-surgery. Measurements of network change could retrospectively predict seizure outcomes with 79% accuracy and 65% specificity, which is twice as high as the empirical distribution. Fifteen connections which changed due to surgery were identified as useful for prediction of outcome, eight of which connected to the ipsilateral temporal pole. Our results suggest that the use of network change metrics may have clinical value for predicting seizure outcome. This approach could be used to prospectively predict outcomes given a suggested resection mask using preoperative data only.
... Data included: age at MRI scan, sex, age at surgery, type and location of surgery, post-operative pathology, age at epilepsy onset, occurrence and frequency of focal seizures with and without impairment of awareness, focal to bilateral tonic-clonic seizures, number of anti-seizure medications (ASMs) at time of surgery, and yearly outcomes of seizure freedom assessed using the International League Against Epilepsy (ILAE) classification. 18 ...
Objective
Magnetic resonance imaging (MRI) is a crucial tool for identifying brain abnormalities in a wide range of neurological disorders. In focal epilepsy, MRI is used to identify structural cerebral abnormalities. For covert lesions, machine learning and artificial intelligence (AI) algorithms may improve lesion detection if abnormalities are not evident on visual inspection. The success of this approach depends on the volume and quality of training data.
Methods
Herein, we release an open‐source data set of pre‐processed MRI scans from 442 individuals with drug‐refractory focal epilepsy who had neurosurgical resections and detailed demographic information. We also share scans from 100 healthy controls acquired on the same scanners. The MRI scan data include the preoperative three‐dimensional (3D) T1 and, where available, 3D fluid‐attenuated inversion recovery (FLAIR), as well as a manually inspected complete surface reconstruction and volumetric parcellations. Demographic information includes age, sex, age a onset of epilepsy, location of surgery, histopathology of resected specimen, occurrence and frequency of focal seizures with and without impairment of awareness, focal to bilateral tonic–clonic seizures, number of anti‐seizure medications (ASMs) at time of surgery, and a total of 1764 patient years of post‐surgical followup. Crucially, we also include resection masks delineated from post‐surgical imaging.
Results
To demonstrate the veracity of our data, we successfully replicated previous studies showing long‐term outcomes of seizure freedom in the range of ~50%. Our imaging data replicate findings of group‐level atrophy in patients compared to controls. Resection locations in the cohort were predominantly in the temporal and frontal lobes.
Significance
We envisage that our data set, shared openly with the community, will catalyze the development and application of computational methods in clinical neurology.
... Seizure outcomes were evaluated according to the ILAE classification 2 years postsurgery. 29 To provide the most relevant and clinically applicable information, the definitive outcome was assessed in all cases as of April 1, 2024, and the long-term outcome was subsequently evaluated in a group of patients 5-13 years after surgery. Postoperative deficit assessments were based on information obtained from regular postoperative neurological follow-ups. ...
Objective
Epilepsy surgery in the operculoinsular cortex is challenging due to the difficult delineation of the epileptogenic zone and the high risk of postoperative deficits.
Methods
Pre‐ and postsurgical data from 30 pediatric patients who underwent operculoinsular cortex surgery at the Motol Epilepsy Center Prague from 2010 to 2022 were analyzed.
Results
Focal cortical dysplasia (FCD; n = 15, 50%) was the predominant cause of epilepsy, followed by epilepsy‐associated tumors (n = 5, 17%) and tuberous sclerosis complex (n = 2, 7%). In eight patients where FCD was the most likely etiology, the histology was negative. Seven patients (23%) displayed normal magnetic resonance imaging results. Seizures exhibited diverse semiology and propagation patterns (frontal, perisylvian, and temporal). The ictal and interictal electroencephalographic (EEG) findings were mostly extensive. Multimodal imaging and advanced postprocessing were frequently used. Stereo‐EEG was used for localizing the epileptogenic zone and eloquent cortex in 23 patients (77%). Oblique electrodes were used as guides for better neurosurgeon orientation. The epileptogenic zone was in the dominant hemisphere in 16 patients. At the 2‐year follow‐up, 22 patients (73%) were completely seizure‐free, and eight (27%) experienced a seizure frequency reduction of >50% (International League Against Epilepsy class 3 and 4). Fourteen patients (47%) underwent antiseizure medication tapering; treatment was completely withdrawn in two (7%). Nineteen patients (63%) remained seizure‐free following the definitive outcome assessment (median = 6 years 5 months, range = 2 years to 13 years 5 months postsurgery). Six patients (20%) experienced corona radiata or basal ganglia ischemia; four (13%) improved to mild and one (3%) to moderate hemiparesis. Two patients (7%) operated on in the anterior insula along with frontotemporal resection experienced major complications: pontine ischemia and postoperative brain edema.
Significance
Epilepsy surgery in the operculoinsular cortex can lead to excellent patient outcomes. A comprehensive diagnostic approach is crucial for surgical success. Rehabilitation brings a great chance for significant recovery of postoperative deficits.
... Patients were classified into two groups based on the surgical outcome at the last follow-up: ILAE I (seizure-free) and II-VI (non-seizure-free), according to the classification criteria of ILAE. 24 The overall seizure-free rate was determined at the last clinical follow-up, and the length of follow-up is detailed in Table 1. ...
Objective
This study assessed the efficacy and safety of magnetic resonance‐guided laser interstitial thermal therapy (MRgLITT) versus open surgery (OS) for the treatment of patients with bottom‐of‐sulcus dysplasia (BOSD)‐related epilepsy.
Methods
Twenty‐two patients underwent MRgLITT, while 39 underwent OS. Postoperative seizure‐free rates were analyzed using Kaplan–Meier curves. The removal ratio, which represents the extent of damage, was calculated based on preoperative lesion volume and postoperative removal volume. Other outcomes, including adverse events, operative time, and hospital stay, were also compared.
Results
Kaplan–Meier curves indicated the seizure‐free rates were comparable between the MRgLITT group (90.9%, 26.5 [23.0, 35.1] months) and OS group (89.7%, 25.2 [16.2, 34.6] months) at the final follow‐up (p = 0.901, log‐rank test). The removal ratio of MRgLITT (1.3 [1.1, 1.7]) was significantly lower (p = 0.007) than that of OS (5.8 [3.6, 8.5]). A comparison of postoperative neurological deficits, infection rates, and fever rates revealed no significant differences between MRgLITT and OS groups. The operative time (hours) of MRgLITT (3.0, [2.1, 4.9]) was significantly shorter (p = 0.007) than that of OS (3.5 [3.0, 4.5]). The hospital stay (days) after MRgLITT (6 [5.0, 7.5]) was significantly shorter (p < 0.001) than that of OS (11.0 [9.0, 13.5]).
Interpretation
MRgLITT has advantages over OS, including comparable seizure control and adverse event profiles, along with reduced removal ratios, shorter operative time, and shorter hospital stays.
... Accessible disease diagnosis and personalized intervention planning are crucial for improving health outcomes for high-mortality diseases such as ischemic heart disease [6], and drug resistant epilepsy [7,8,9] as well as chronic illnesses such as Type 1 diabetes (T1D) [5]. In such domains, precision medicine [10] has become increasingly important. ...
Precision medicine is a promising approach for accessible disease diagnosis and personalized intervention planning in high-mortality diseases such as coronary artery disease (CAD), drug-resistant epilepsy (DRE), and chronic illnesses like Type 1 diabetes (T1D). By leveraging artificial intelligence (AI), precision medicine tailors diagnosis and treatment solutions to individual patients by explicitly modeling variance in pathophysiology. However, the adoption of AI in medical applications faces significant challenges, including poor generalizability across centers, demographics, and comorbidities, limited explainability in clinical terms, and a lack of trust in ethical decision-making. This paper proposes a framework to develop and ethically evaluate expert-guided multi-modal AI, addressing these challenges in AI integration within precision medicine. We illustrate this framework with case study on insulin management for T1D. To ensure ethical considerations and clinician engagement, we adopt a co-design approach where AI serves an assistive role, with final diagnoses or treatment plans emerging from collaboration between clinicians and AI.
... The patients were monitored at the Brain electrophysiology, Epilepsy and Sleep Unit, department of Neurology, at Toulouse University Hospital to identify and possibly resect the brain areas involved in seizure generation, between 2009 and 2020. If surgery was offered, its outcome was rated using the International League Against Epilepsy (ILAE) rating scale 49 . iEEG were retrospectively collected with the following inclusion criteria: over 12 years of age, temporal involvement in the epileptogenic network, recording electrodes implanted in the temporal lobe, and an available iEEG recording of the . ...
The clinical workup during the pre-surgical evaluation for epilepsy relies on the electrophysiological recording of spontaneous seizures. The interval until first seizure occurrence is characterized by an increase in seizure likelihood caused by progressive drug dose decreases, during which the epileptic brain transitions from a state of low to a state of high seizure likelihood, so-called pro-ictal state. This study aimed to identify the dynamic brain changes characteristic of this transition from 386 ten-minute segments of intracranial EEG recordings of 29 patients with drug-refractory temporal lobe epilepsy, explored by stereoelectroencephalography, irregularly sampled between electrode implantation and first seizure. As measures of brain dynamics we studied mean phase coherence and relative power in the gamma frequency band, and autocorrelation function width. We further investigate the interaction of those brain dynamics with various susceptibility factors, such as the rate of interictal spikes and high frequency oscillations, circadian and multi-day cycles, and clinical outcomes. We observed a significant increase in relative gamma power in the epileptogenic zone, and an increase in critical slowing in both the epileptogenic zone as well as in presumably healthy cortex. These brain dynamic changes were linked with increases in spike and high frequency oscillations rate. While brain dynamic changes occurred on the slow time scale - from the beginning to the end of the multi-day interval - they did not change in the short-term during the pre-ictal interval. We thus highlight gamma power and critical slowing indices as markers of pro-ictal (as opposed to pre-ictal) brain states, as well as their potential to track the seizure-related brain mechanisms during the presurgical evaluation of epilepsy patients.
Key Points
We investigated the multi-day changes in brain dynamics during presurgical evaluation of patients with drug-resistant temporal lobe epilepsy, inside the epileptogenic zone as well as in healthy brain tissue.
This time interval of increasing seizure susceptibility is marked by increases in gamma band power in the epileptogenic zone and network-wide increase in critical slowing.
The identified multi-day changes were consistently linked to the changes in spikes and high-frequency oscillations (HFOs), while not to other factors like drug dose and circadian time.
While gamma power and critical slowing changed on the scale of days, there was no significant increase in the minutes before seizures, suggesting the brain dynamic changes during presurgical evaluation are likely a multi-day phenomenon associated with pro-ictal states.
... The EZ was determined based on the SEEG monitoring ictal discharges (primary seizure onset zone plus early spreading areas), interictal discharges, MRI and 18 F-FDG PET by multiple discipline disccusion. The prognosis was based on the ILAE classification [17]: Class 1 = completely seizure-free and no auras; Class 2 = only auras and no other seizures; Class 3 = one-three seizure days per year ± auras; Class 4 = four seizure days per year to 50% reduction in baseline seizure days ± auras; Class 5 = less than 50% reduction in baseline seizure days to 100% increase in baseline seizure days ± auras; Class 6 = more than 100% increase in baseline seizure days ± auras. All the surgical procedures were performed by the same senior surgeon. ...
Purpose
Accurate detection and resection of the epileptogenic zone (EZ) in patients with long-term epilepsy-associated tumors (LEATs) are significantly correlated with favorable seizure prognosis. However, the relationship between tumors and the EZ remains unknown. This study aimed to evaluate the spatial relationship between LEATs and the EZ, as well as the electrophysiological features of LEATs.
Methods
We retrospectively studied five patients with LEATs who underwent deep electrode implantation and EZ resection in the hospital. The clinical characteristics, surgical outcomes, localizing features and intracranial SEEG results were reviewed.
Results
One female and four males (mean age: 25.2 years; median age: 24 years; range: 13–45 years) were included in the study. Five-to-eleven electrodes (mean: 8.4) were implanted per patient. The EZ was located in the tumor and nearby cortex in three cases and in the tumor and distant areas in two cases. Pathological examination revealed ganglioglioma in four cases, two of which were associated with hippocampal sclerosis, and the other case showed a multinodular and vacuolating neuronal tumor with gliosis. All patients were seizure-free for at least 24 months postoperatively.
Conclusions
SEEG provides valuable insights into the electrophysiological mechanisms of LEATs. The EZ often contains brain tissue around the tumor. However, only a few cases, particularly those with temporoparietal occipital (TPO) area involvement, a long history of epilepsy and other abnormalities on MRI, such as hippocampal sclerosis and focal cortical dysplasia, may include distant areas.
... In addition, reduced axonal labelling was observed with age (NF-M, Deep; p < 0.05) and more pronounced the longer the epilepsy (NF-H, Deep; p < 0.01) (Supplemental Fig. 9B,E). There were no differences for vascular, glial, axonal or myelin markers in relation to hemisphere side; 23/45 patients were categorized as seizure-free following surgery at 2 years follow up [80], but there was no statistical relationship between seizure outcome and pathology measures. Gene expression of MAG, PLLP, Olig2 and PDGFRβ was compared between patients with an age of surgery lower or equal to 40 years and over 40 years of age; the older cohort showed lower expression of MAG, PLLP, OLIG2 mRNA whereas PDGFRβ RNA level appeared to be slightly higher (Supplemental Fig. 9G). ...
White matter microvascular alterations in temporal lobe epilepsy (TLE) may be relevant to acquired neurodegenerative processes and cognitive impairments associated with this condition. We quantified microvascular changes, myelin, axonal, glial and extracellular-matrix labelling in the gyral core and deep temporal lobe white matter regions in surgical resections from 44 TLE patients with or without hippocampal sclerosis. We compared this pathology data with in vivo pre-operative MRI diffusion measurements in co-registered regions and neuropsychological measures of cognitive impairment and decline. In resections, increased arteriolosclerosis was observed in TLE compared to non-epilepsy controls (greater sclerotic index, p < 0.001), independent of age. Microvascular changes included increased vascular densities in some regions but uniformly reduced mean vascular size (quantified with collagen-4, p < 0.05–0.0001), and increased pericyte coverage of small vessels and capillaries particularly in deep white matter (quantified with platelet-derived growth factor receptorβ and smooth muscle actin, p < 0.01) which was more marked the longer the duration of epilepsy (p < 0.05). We noted increased glial numbers (Olig2, Iba1) but reduced myelin (MAG, PLP) in TLE compared to controls, particularly prominent in deep white matter. Gene expression analysis showed a greater reduction of myelination genes in HS than non-HS cases and with age and correlation with diffusion MRI alterations. Glial densities and vascular size were increased with increased MRI diffusivity and vascular density with white matter abnormality quantified using fixel-based analysis. Increased perivascular space was associated with reduced fractional anisotropy as well as age-accelerated cognitive decline prior to surgery (p < 0.05). In summary, likely acquired microangiopathic changes in TLE, including vascular sclerosis, increased pericyte coverage and reduced small vessel size, may indicate a functional alteration in contractility of small vessels and haemodynamics that could impact on tissue perfusion. These morphological features correlate with white matter diffusion MRI alterations and might explain cognitive decline in TLE.
... If patients underwent resective surgery after multidisciplinary preoperative evaluation, postoperative seizure outcomes were followed up according to the International League Against Epilepsy (ILAE) classification. 33 The inclusion criteria were as follows: (1) patients were diagnosed with TLE according to the ILAE criteria 34 ; (2) patients with at least one usual seizure recorded by video EEG and with clear ictal semiology that could distinguish dystonic posturing; (3) patients with seizure onset from unilateral mesiotemporal regions demonstrated by video EEG; and (4) patients with normal brain MRI or with unilateral hippocampal sclerosis compatible with EEG findings. ...
Objective
Dystonic posturing (DP) is a common semiology in temporal lobe epilepsy (TLE). We aimed to explore cerebellar gradient alterations in functional connectivity in TLE patients with and without DP.
Methods
Resting‐state functional MRI data were obtained in 60 TLE patients and 32 matched healthy controls. Patients were further divided into two groups: TLE with DP (TLE + DP, 31 patients) and TLE without DP (TLP‐DP, 29 patients). We explored functional gradient alterations in the cerebellum based on cerebellar–cerebral functional connectivity and combined with independent component analysis to evaluate cerebellar–cerebral functional integration and reveal the contribution of the motor components to the gradient.
Results
There were no obvious differences in clinical features and postoperative seizure outcomes between TLE + DP and TLE‐DP patients. Patients and controls all showed a clear unimodal‐to‐transmodal gradient transition in the cerebellum, while TLE patients demonstrated an extended principal gradient in functional connectivity compared to healthy controls, which was more limited in TLE + DP patients. Gradient alterations were more widespread in TLE‐DP patients, involving bilateral cerebellum, while gradient alterations in TLE + DP patients were limited in the cerebellum ipsilateral to the seizure focus. In addition, more cerebellar motor components contributed to the gradient alterations in TLE + DP patients, mainly in ipsilateral cerebellum.
Significance
Extended cerebellar principal gradients in functional connectivity revealed excessive functional segregation between unimodal and transmodal systems in TLE. The functional connectivity gradients were more limited in TLE + DP patients. Functional connectivity in TLE patients with dystonic posturing involved more contribution of cerebellar motor function to ipsilateral cerebellar gradient.
Plain Language Summary
Dystonic posturing contralateral to epileptic focus is a common symptom in temporal lobe epilepsy, and the cerebellum may be involved in its generation. In this study, we found cerebellar gradients alterations in functional connectivity in temporal lobe epilepsy patients with and without contralateral dystonic posturing. In particular, we found that TLE patients with dystonic posturing may have more limited cerebellar gradient in functional connectivity, involving more contribution of cerebellar motor function to ipsilateral cerebellar gradient. Our study suggests a close relationship between ipsilateral cerebellum and contralateral dystonic posturing.
... Each patient's surgical and neurological (transient and persistent) outcomes were assessed after surgery. Postoperative outcomes concerning epileptic seizures after surgery were assessed using the International League Against Epilepsy (ILAE) outcome classification [37] at in-house follow-up examinations or during structured telephone interviews. ...
Background: Epilepsy surgery for extratemporal lobe epilepsy (ETLE) is challenging, particularly when MRI findings are non-lesional and seizure patterns are complex. Invasive diagnostic techniques are crucial for accurately identifying the epileptogenic zone and its relationship with surrounding functional tissue. Microscope-based augmented reality (AR) support, combined with navigation, may enhance intraoperative orientation, particularly in cases involving subtle or indistinct lesions, thereby improving patient outcomes and safety (e.g., seizure freedom and preservation of neuronal integrity). Therefore, this study was conducted to prove the clinical advantages of microscope-based AR support in ETLE surgery. Methods: We retrospectively analyzed data from ten patients with pharmacoresistant ETLE who underwent invasive diagnostics with depth and/or subdural grid electrodes, followed by resective surgery. AR support was provided via the head-up displays of the operative microscope, with navigation based on automatic intraoperative computed tomography (iCT)-based registration. The surgical plan included the suspected epileptogenic lesion, electrode positions, and relevant surrounding functional structures, all of which were visualized intraoperatively. Results: Six patients reported complete seizure freedom following surgery (ILAE 1), one patient was seizure-free at the 2-year follow-up, and one patient experienced only auras (ILAE 2). Two patients developed transient neurological deficits that resolved shortly after surgery. Conclusions: Microscope-based AR support enhanced intraoperative orientation in all cases, contributing to improved patient outcomes and safety. It was highly valued by experienced surgeons and as a training tool for less experienced practitioners.
... Post-surgical seizure outcome at the last follow-up was used as the basis of outcome classification. Patients who were seizure free postoperatively (equivalent to Engel Classification Class IA-D or International League Against Epilepsy ILAE Classes 1 and 2) were considered 'surgical success' cases while all others (Engel II-IV or ILAE 3-6) were considered 'surgical failure' cases 33 . To ascertain differences in the baseline characteristics of patients in the surgical success and surgical failure groups, we applied inferential tests; two-sided t tests were applied for comparison of means, Fisher Exact tests were applied for comparison of proportions when only two categories were present, Chi square tests were applied when more than 2 categories were present. ...
Brain resection is curative for a subset of patients with drug resistant epilepsy but up to half will fail to achieve sustained seizure freedom in the long term. There is a critical need for accurate prediction tools to identify patients likely to have recurrent postoperative seizures. Results from preclinical models and intracranial EEG in humans suggest that the window of time immediately before and after a seizure (“peri-ictal”) represents a unique brain state with implications for clinical outcome prediction. Using a dataset of 294 patients who underwent temporal lobe resection for seizures, we show that machine learning classifiers can make accurate predictions of postoperative seizure outcome using 5 min of peri-ictal scalp EEG data that is part of universal presurgical evaluation (AUC 0.98, out-of-group testing accuracy > 90%). This is the first approach to seizure outcome prediction that employs a routine non-invasive preoperative study (scalp EEG) with accuracy range likely to translate into a clinical tool. Decision curve analysis (DCA) shows that compared to the prevalent clinical-variable based nomogram, use of the EEG-augmented approach could decrease the rate of unsuccessful brain resections by 20%.
... Severity of epilepsy was appraised using the National Hospital Seizure Severity Scale (NHS3) (26), which is a measure incorporating seven seizure-related factors, with a scoring range from 1 to 27. Post-treatment seizure attack frequency for each patient was systematically evaluated based on the criteria established by the ILAE scale (27). ...
Background
The glymphatic system is essential for the maintenance of brain homeostasis. It may be impaired in patients with epilepsy, but its association with neurocognitive function remains unknown. In this study, we aimed to elucidate the association between changes in the glymphatic system and neurocognitive function in individuals diagnosed with frontal lobe epilepsy (FLE).
Methods
This retrospective case-control research engaged a group of patients with FLE and age-, sex-, and education-matched healthy volunteers. All participants were subjected to extensive neurocognitive assessments, complemented by structural and diffusion-weighted imaging. The “diffusion tensor imaging analysis along the perivascular space” (DTI-ALPS) index was computed to ascertain differences in glymphatic system function between the groups. Univariate and multivariate analyses were conducted to explore associations between DTI-ALPS, clinical characteristics in patients with FLE, and the neurocognitive test outcomes for both groups.
Results
Twenty-five patients [mean age ± standard deviation (SD): 26.28±8.12 years, 10 females] with FLE and 22 healthy control (HC) participants (average age ± SD: 25.86±6.15 years, 11 females) were included. The average ALPS-index in FLE group was significantly lower than that in HC group (1.387±0.127 vs. 1.468±0.114, P=0.026). Further, significant neurocognitive difference was noted in Trail Making Test (TMT), Stroop Color and Word Test (SCWT), Digit Span Test (DST) and similarity test (ST) between the two groups. ALPS-index scores exhibited a negative correlation with disease duration in patients with FLE (r=−0.415, P=0.039), and positive correlations with the Forward Digit Span Test (FDST, r=0.399, P=0.005) and Similarity Test (ST, r=0.395, P=0.006) in both groups. After adjusting for potential confounders, DTI-ALPS maintained a significant independent association with FDST and ST.
Conclusions
The findings of the current study suggest a possible association between impairment in glymphatic function and FLE. Furthermore, results indicate that glymphatic dysfunction, as assessed via DTI-ALPS index, appears to be related to neurocognitive decline in FLE.
... Information on the seizure outcome at 12 months after epilepsy surgery was available in 44 patients. The seizure outcome was favorable (Engel outcome scale I or II [16,17]) in 33 of these patients (75.0%). Among the 33 patients with favorable 12 months seizure outcome, surgery had been on the temporal lobe in 31 patients (93.9%, ...
Background
Ictal brain perfusion SPECT provides higher sensitivity for the identification of the epileptic seizure onset zone (SOZ) than interictal SPECT. However, ictal SPECT is demanding due to the unpredictable waiting period for the next seizure to allow for ictal tracer injection. Thus, starting with an interictal scan and skipping the ictal scan if the interictal scan provides a SOZ candidate with high confidence could be an efficient approach. The current study estimated the rate of high-confidence SOZ candidates and the false lateralization rate among them for interictal and ictal SPECT.
Methods
177 patients (48% females, median age 38y, interquartile range 27–48y) with ictal and interictal SPECT acquired with 99mTc-HMPAO (n = 141) or -ECD (n = 36) were included retrospectively. The vast majority of the patients was suspected to have temporal lobe epilepsy. Visual interpretation of the SPECT data was performed independently by 3 readers in 3 settings: “interictal only” (interictal SPECT and statistical hypoperfusion map), “ictal only” (ictal SPECT and hyperperfusion map), and “full” setting (side-by-side interpretation of ictal and interictal SPECT including statistical maps and SISCOM analysis). The readers lateralized the SOZ (right, left, none) and characterized their confidence using a 5-score. A case was considered "lateralizing with high confidence” if all readers lateralized to the same hemisphere with at least 4 of 5 confidence points. Lateralization of the SOZ in the “full” setting was used as reference standard.
Results
The proportion of “lateralizing with high confidence” cases was 4.5/31.6/38.4% in the “interictal only”/“ictal only”/“full” setting. One (12.5%) of the 8 cases that were “lateralizing with high confidence” in the “interictal only” setting lateralized to the wrong hemisphere. Among the 56 cases that were “lateralizing with high confidence” in the “ictal only” setting, 54 (96.4%) were also lateralizing in the “full” setting, all to the same hemisphere.
Conclusions
Starting brain perfusion SPECT in the presurgical evaluation of epilepsy with an interictal scan to skip the ictal scan in case of a high-confidence interictal SOZ candidate is not a useful approach. In contrast, starting with an ictal scan to skip the interictal scan in case of a high-confidence ictal SOZ candidate can be recommended.
Objective
Patients with tuberous sclerosis complex (TSC)‐related epilepsy often have drug‐refractory epilepsy and numerous potential epileptogenic tubers. Current clinical methods target tubers for resection, but prediction of resulting seizure relief is difficult. This study describes implementation of lesion network mapping in TSC patients undergoing epilepsy surgery to associate resection zone with seizure outcomes.
Methods
Thirty‐nine consecutive patients with TSC who underwent invasive electroencephalography (EEG) and resection or ablation of the seizure onset zone were included. After preprocessing, each resection zone was delineated as the region of interest. Lesion network mapping was performed to determine the association between cortical networks connected to the resection zone and postoperative outcome using a multiple regression, iterative model that included demographic and other variables obtained from analysis of invasive EEG.
Results
Of 39 patients, 20 (51%) had a good International League Against Epilepsy outcome (1–3). Resection regions connected to the default mode network and motor network were associated with better seizure outcome. Regions connected to the bilateral insula, visual associative regions, and putamen were associated with poor seizure outcome.
Significance
This study provides methodology for lesion network mapping in TSC‐related epilepsy. The results suggest a tendency for better outcomes when the resection zone is connected to certain networks, including the default mode and motor networks, that may support sustainment of seizures.
Approximately 40% of individuals undergoing anterior temporal lobe resection for temporal lobe epilepsy experience episodic memory decline. There has been a focus on early memory network changes; longer-term plasticity and its impact on memory function are unclear. Our study investigates neural mechanisms of memory recovery and network plasticity over nearly a decade post-surgery. We assess memory network changes, from 3–12 months to 10 years postoperatively, in 25 patients (12 left-sided resections) relative to 10 healthy matched controls, using longitudinal task-based functional MRI and standard neuropsychology assessments. We observe key adaptive changes in memory networks of a predominantly seizure-free cohort. Ongoing neuroplasticity in posterior medial temporal regions and contralesional cingulum or pallidum contribute to long-term verbal and visual memory recovery. Here, we show the potential for sustained cognitive improvement and importance of strategic approaches in epilepsy treatment, advocating for conservative surgeries and long-term use of cognitive rehabilitation for ongoing recovery.
Objective
Hypothalamic hamartomas (HHs) are associated with pharmacoresistant epilepsy. Stereotactic radiofrequency thermocoagulation (SRT) shows promise as a disconnecting intervention. Although magnetic resonance imaging (MRI) is typically used to determine the attachment and intervention side, it presents challenges in cases of bilaterally attached HH, where the epileptogenic side is unclear. The lateralizing potential of electroclinical parameters in such cases remains uncertain. This retrospective study evaluates the lateralization value of specific parameters, particularly in patients with unilateral HH, to improve future diagnostics and treatment approaches for bilateral HH.
Methods
Four lateralizing parameters—semiology, ictal electroencephalography (EEG), and interictal epileptiform discharges during awake (IEDsw) and sleep states (IEDss)—were assessed for correlation with HH attachment side using Spearman's ρ. We calculated areas under the curves (AUCs) and cutoffs for left and right IEDs prognostic lateralizing value, plotting differences between IEDsright and IEDsleft in a receiver‐operating characteristic(ROC) curve to establish the required preponderance of unilateral IEDss to differentiate between left and right HHs. Binomial logistic regression was employed to predict the HH attachment side.
Results
We included 25 patients (2–55 years of age) with mainly unilateral (n = 22) HHs who underwent SRT and presurgical evaluation. All parameters correlated with HH attachment side (semiology R = −.62, p = .005; ictal EEG R = .51, p = .047; IEDs R = .55, p = .018; IEDw, R = .61, p = .018). AUC values for right and left IEDs were .76 (p = .047) and .85 (p = .019), respectively, with cutoffs of .34 and .15. The AUC for “IEDsright–IEDsleft” was .98 (p = .0018) with a cutoff of .16. IEDss and semiology were significant predictors, achieving 88% correct lateralization.
Significance
IEDss are promising biomarkers for HH lateralization in unilateral HH. The predominance of unilateral IEDss suggests ipsilateral HH. Even in cases with predominantly bilateral IEDss, a slight preponderance of unilateral IEDss can indicate the attachment side. In addition, combining IEDss and semiology provides a predictive model for HH lateralization.
Objective
This investigation aimed to elucidate alterations in metabolic brain network connectivity in drug-resistant mesial temporal lobe epilepsy (DR-MTLE) patients, relating these changes to varying surgical outcomes.
Methods
A retrospective cohort of 87 DR-MTLE patients who underwent selective amygdalohippocampectomy was analyzed. Patients were categorized based on Engel surgical outcome classification into seizure-free (SF) or non-seizure-free (NSF) groups. Additionally, 38 healthy individuals constituted a control group (HC). Employing effect size (ES) methodology, we constructed individualized metabolic brain networks and compared metabolic connectivity matrices across these groups using the DPABINet toolbox.
Results
Compared to HCs, both SF and NSF groups exhibited diminished metabolic connectivity, with the NSF group showing pronounced reductions across the whole brain. Notably, the NSF group demonstrated weaker metabolic links between key networks, including the default mode network (DMN), frontoparietal network (FPN), and visual network (VN), in comparison to the SF group.
Conclusion
Individual metabolic brain networks, constructed via ES methodology, revealed significant disruptions in DR-MTLE patients, predominantly in the NSF group. These alterations, particularly between limbic structures and cognitive networks like the DMN, suggested impaired and inefficient information processing across the brain’s networks. This study identified abnormal brain networks associated with DR-MTLE and, importantly, contributed novel insights into the mechanisms underlying poor postoperative seizure control, and offered potential implications for refining preoperative assessments.
Epileptic spasms (ES) are a unique seizure type typically presenting in the form of infantile epileptic spasms syndrome (IESS) with characteristic hypsarrhythmia on scalp EEG and a preponderance with developmental delay or regression. While pharmacotherapy is the mainstay of treatment, surgical options, including disconnective or resective procedures, are increasingly recognized as viable therapeutic options for recurrent or persistent ES. However, limited data on safety, effectiveness, and prognostic factors hinder informed decision-making regarding surgery indications, timing, and intervention type. We performed a systematic review and an individual patient data meta-analysis (IPDMA) in accordance with PRISMA guidelines, focusing on surgical interventions for ES and reporting seizure outcomes using the Engel or ILAE scales. Twenty-six studies encompassing 358 ES patients undergoing resection/callosotomy were included. Participants undergoing other approaches (e.g., multiple subpial transections) or multimodality approaches were excluded from analysis. The median age at spasm onset was 6 months (IQR = 3.0–15.6), with a median age at surgery of 37 months (IQR = 17.2–76.8). Most patients (74.1%) exhibited additional seizure types. A total of 136 patients (35.8%) underwent corpus callosotomy (CC), of whom 125 (91.9%) had a complete callosotomy, while 11 (8.1%) had a partial callosotomy. Resective surgery was performed on 222 patients (58.4%). Among those who underwent resection, 109 (49.1%) had both lesional MRI findings and lateralized EEG abnormalities. Overall, 201 patients (56.1%) remained spasm-free at a median postoperative follow-up of 36 months (interquartile range, IQR = 21–60), including 52 (38.2%) from the callosotomy group and 149 (67.1%) from the resective surgery group. In the resective surgery cohort, patients with MRI-confirmed lesions (p = 0.026; HR = 0.53, 95% CI = 0.31–0.93) and those who underwent hemispherectomy (p = 0.026, HR = 0.46, 95% CI = 0.23–0.91) had better seizure outcomes. Only a minority (24.4%) underwent invasive EEG monitoring prior to ES surgery. Surgical treatment of ES proves effective, with two thirds of patients undergoing resective surgery and a third undergoing CC becoming spasm free. Post-operative developmental improvement was observed in 44 participants (65.7% of those with available data). The presence of lesional MRI and more extensive resection/disconnection (e.g., hemispherectomy) emerged as significant prognostic factors for spasm freedom and can inform clinical decision-making.
Objective
Epilepsy is associated with progressive cortical atrophy exceeding normal aging. We aimed to explore longitudinal cortical alterations in patients with temporal lobe epilepsy (TLE) and distinct surgery outcomes.
Methods
We obtained longitudinal T1‐weighted MRI data in a well‐designed cohort, including 53 operative TLE patients, 23 nonoperative TLE patients, and 23 healthy controls. According to seizure outcomes at 24 months after surgery, operative patients were divided into seizure‐free (SF) and nonseizure‐free (NSF) group. Operative patients were scanned before and after surgery, while nonoperative patients and healthy controls were rescanned with similar interval times. We measured gray matter volume (GMV) in all participants and compared longitudinal cortical alterations among groups.
Results
In nonoperative group, statistically significant GMV decrease was observed in ipsilateral median cingulate and paracingulate gyri and cerebellum crus I when compared with healthy controls. In operative group, postoperative GMV increase was discovered in many regions involving bilateral hemispheres, especially in the frontal lobe, without differences between SF and NSF group. Postoperative GMV decrease was found in ipsilateral inferior frontal gyrus, putamen, thalamus, and insula. GMV decrease in ipsilateral inferior frontal gyrus, putamen, and insula was more significant in SF group.
Interpretation
Progressive cortical atrophy existed in nonoperative TLE patients. Cortical remodeling indicated by postoperative GMV increase may arise mostly from the surgery itself, rather than postsurgical seizure outcomes. More significant GMV decrease in ipsilateral inferior frontal gyrus, putamen, and insula may imply their closer connections with resected regions in seizure‐free patients.
OBJECTIVE
Since the recent development of stereotactic ablation surgery, which can provide good seizure outcomes without limitations in size or location, conventional classification systems have become unsuitable for surgical guidance. The present study aimed to evaluate the validity of a newly proposed classification system focusing on the attachment pattern.
METHODS
This retrospective study investigated 218 patients with hypothalamic hamartomas who underwent MRI-guided stereotactic radiofrequency thermocoagulation and were followed for at least 1 year after their last surgery. Hypothalamic hamartomas were classified by their attachments into six subtypes: parahypothalamic-unilateral (PU), parahypothalamic-bilateral (PB), intrahypothalamic-unilateral (IU), intrahypothalamic-bilateral (IB), mixed-unilateral (MU), and mixed-bilateral (MB) types. Clinical features, surgical factors, scales of surgical procedures including numbers of trajectories and coagulations, requirement for a trans–third ventricular approach, reoperation rates, and complication rates were investigated. Seizure outcomes were evaluated separately for gelastic seizures (GSs) and non-GSs.
RESULTS
In 218 patients (131 [60.1%] males, median age at surgery 7.2 [range 1.8–51] years), the hypothalamic hamartomas were classified as PU type in 10 (4.6%), PB type in 11 (5.0%), IU type in 41 (18.8%), IB type in 17 (7.8%), MU type in 40 (18.3%), and MB type in 99 (45.4%) patients. Patients with MB type were significantly younger at GS onset (p < 0.001) and surgery (p = 0.005). The numbers of trajectories and coagulations were significantly greater in MB type (p < 0.001) and the trans–third ventricular approach was more often required in the PB type (5/6, 83.3%, p < 0.001). Seizure outcomes were not different among subtypes. The rate of transient complications was not different among subtypes, but hyperthermia (p = 0.002) and hyponatremia (p < 0.001) were more frequently found in patients with PB and MB types. Prolonged or persistent neurological complications were also not different and were only found in bilateral subtypes.
CONCLUSIONS
The new classification predicts clinical features, as well as surgical complexity and complications. Although seizure outcomes were not different among subtypes because the authors’ surgical strategy is consistently based on complete disconnection at the border, the new classification could improve seizure outcomes and would be helpful in the appropriate guidance for surgery of hypothalamic hamartomas to provide consistently good outcomes regardless of surgical procedures.
Neural representations for visual stimuli typically emerge with a bilateral distribution across occipitotemporal cortex (OTC)? Pediatric patients undergoing unilateral OTC resection offer an opportunity to evaluate whether representations for visual stimulus individuation can sufficiently develop in a single OTC. Here, we assessed the non-resected hemisphere of patients with pediatric resection within (n = 9) and outside (n = 12) OTC, as well as healthy controls’ two hemispheres (n = 21). Using functional magnetic resonance imaging, we mapped category selectivity (CS), and representations for visual stimulus individuation (for faces, objects, and words) with repetition suppression (RS). There were no group differences in CS or RS. However, OTC resection patients’ accuracy on face and object (but not word) recognition was lower than controls’. The neuroimaging results highlight neural resilience following damage to the contralateral homologue. Critically, however, a single OTC does not suffice for typical behavior, and, thereby, implicates the necessary contributions of bilateral OTC for visual recognition.
In drug-resistant focal epilepsy, planning surgical resection may involve presurgical intracranial EEG recordings (iEEG) to detect seizures and other iEEG patterns to improve postsurgical seizure outcome. We hypothesized that resection of tissue generating interictal high frequency oscillations (HFOs, 80-500 Hz) in the iEEG predicts surgical outcome.
Eight international epilepsy centres recorded iEEG during the patients’ pre-surgical evaluation. The patients were of all ages, had epilepsy of all types, and underwent surgical resection of a single focus aiming at seizure freedom. In a prospective analysis we applied a fully automated definition of HFO which was independent of the dataset. Using an observational cohort design that was blinded to postsurgical seizure outcome, we analysed HFO rates during non-rapid-eye-movement sleep. If channels had consistently high rates over multiple epochs, they were labelled the “HFO area”. After HFO analysis, centres provided the electrode contacts located in the resected volume and the seizure outcome at follow-up ≥24 months after surgery. The study was registered at www.clinicaltrials.gov (NCT05332990).
We received 160 iEEG datasets. In 146 datasets (91%), the HFO area could be defined. The patients with completely resected HFO area were more likely to achieve seizure freedom compared to those without (OR 2.61 CI [1.15-5.91], P = 0.02). Among seizure free patients, the HFO area was completely resected in 31 and was not completely resected in 43. Among patients with recurrent seizures, the HFO area was completely resected in 14 and was not completely resected in 58. When predicting seizure freedom, the negative predictive value of the HFO area (68% CI [52-81]) was higher than that for the resected volume as predictor by itself (51% CI [42-59], P = 4e-5). The sensitivity and specificity for complete HFO area resection were 0.88 CI [0.72-0.98] and 0.39 CI [0.25-0.54] and the area under the curve was 0.83 CI [0.58-0.97], indicating good predictive performance.
In a blinded cohort study from independent epilepsy centres, applying a previously validated algorithm for HFO marking without the need of adjusting to new datasets allowed us to validate the clinical relevance of HFOs to plan the surgical resection.
Objective
Anterior temporal lobe resection (ATLR) is an effective treatment for drug‐resistant temporal lobe epilepsy (TLE), although language deficits may occur after both left and right ATLR. Functional reorganization of the language network has been observed in the ipsilateral and contralateral hemispheres within 12 months after ATLR, but little is known of longer‐term plasticity effects. Our aim was to examine the plasticity of language functions up to a decade after ATLR, in relation to cognitive profiles.
Methods
We examined 24 TLE patients (12 left [LTLE]) and 10 controls across four time points: pre‐surgery, 4 months, 12 months, and ~9 years post‐ATLR. Participants underwent standard neuropsychological assessments (naming, phonemic, and categorical fluency tests) and a verbal fluency functional magnetic resonance imaging (fMRI) task. Using a flexible factorial design, we analyzed longitudinal fMRI activations from 12 months to ~9 years post‐ATLR, relative to controls, with separate analyses for people with hippocampal sclerosis (HS). Change in cognitive profiles was correlated with the long‐term change in fMRI activations to determine the “efficiency” of reorganized networks.
Results
LTLE patients had increased long‐term engagement of the left extra‐temporal and contralateral temporal regions, with better language performance linked to bilateral activation. Those with HS exhibited more widespread bilateral activations. RTLE patients showed plasticity in the left extra‐temporal regions, with better language outcomes associated with these areas. Both groups of patients achieved cognitive stability over 9 years, with more than 50% of LTLE patients improving. Older age, longer epilepsy duration, and lower pre‐operative cognitive reserve negatively affected long‐term language performance.
Significance
Neuroplasticity continues for up to ~9 years post‐epilepsy surgery in LTLE and RTLE, with effective language recovery linked to bilateral engagement of temporal and extra‐temporal regions. This adaptive reorganization is associated with improved cognitive outcomes, challenging the traditional view of localized surgery effects. These findings emphasize the need for early intervention, tailored pre‐operative counseling, and the potential for continued cognitive gains with extended post‐ATLR rehabilitation.
Objective
Cortical atrophy close to medial temporal structures has been described consistently in patients with temporal lobe epilepsy (TLE). Successful TLE surgery may have a neuroprotective effect preventing further atrophy of temporal and extratemporal cortex. However, the effects of epilepsy surgery on subcortical structures demand additional enlightenment. This work aimed to determine how epilepsy surgery affects volumes of subcortical structures in medically refractory temporal lobe epilepsy patients.
Methods
We compared MRI volumes of subcortical structures in 62 patients with TLE (36 left, 26 right) before and after anterior temporal lobectomy with 38 TLE patients (20 left, 18 right) who were considered to be good surgical candidates and had at least two brain MRIs.
Results
There were no volume differences in subcortical structures on preoperative and initial MRIs of non‐operated TLE patients. At baseline, the ipsilateral thalamus and putamen in TLE patients were marginally smaller than contralateral structures. Operated patients showed a significant postoperative volume reduction in ipsilateral thalamus, putamen, and globus pallidus. In contrast, there were no significant volumetric reductions in non‐operated patients longitudinally. There were no volumetric changes associated with different surgical outcomes or different postoperative cognitive outcomes.
Significance
Our study demonstrated postoperative volume loss of thalamus, putamen and globus pallidus ipsilaterally to the side of resection. Our findings suggest surgery‐related changes, likely Wallerian degeneration within subcortical networks not related to seizure or cognitive outcome.
Plain Language Summary
We studied 100 patients with epilepsy, comparing those who had surgery to those who did not. After surgery, the thalamus, putamen and globus pallidus on the same side as the surgery shrank significantly, but not in non‐surgery patients. This suggests surgery‐related changes in deeper brain structures, unrelated to seizure freedom or cognitive outcomes. This research sheds additional light on the response of the subcortical structure to epilepsy surgery, highlighting potential areas for further study.
Objective
Epilepsy raises critical challenges to accurately localize the epileptogenic zone (EZ) to guide presurgical planning. Previous research has suggested that interictal spikes overlapping with high‐frequency oscillations, referred to here as pSpikes, serve as a reliable biomarker for EZ estimation, but there remains a question as to whether and to how pSpikes perform as compared to other types of epileptic spikes. This study aims to address this question by investigating the source imaging capabilities of pSpikes alongside other spike types.
Methods
A total of 2819 interictal spikes from 76‐channel scalp electroencephalography (EEG) were analyzed in a cohort of 24 drug‐resistant focal epilepsy patients. All patients received surgical resection, and 16 were declared seizure‐free based on at least 1 year of postoperative follow‐up. A recently developed electrophysiological source imaging algorithm—fast spatiotemporal iteratively reweighted edge sparsity (FAST‐IRES)—was used for source imaging of the detected interictal spikes. The performance of 217 pSpikes was compared with 772 nSpikes (spikes with irregular high‐frequency activations), 1830 rSpikes (spikes with no high‐frequency activity), and all 2819 aSpikes (all interictal spikes).
Results
The localization and extent estimation using pSpikes are concordant with the clinical ground truth; using pSpikes yields the best performance compared with nSpikes, rSpikes, and conventional spike imaging (aSpikes). For multiple spike type seizure‐free patients, the mean localization error for pSpike imaging was 6.8 mm, compared with 15.0 mm for aSpikes. The sensitivity, precision, and specificity were .41, .67, and .93 for pSpikes compared with .32, .48, and .93 for aSpikes.
Significance
These results demonstrate the merits of noninvasive EEG source localization, and that (1) pSpike is a superior biomarker, outperforming conventional spike imaging for the localization of epileptic sources, and especially those with multiple irritative zones; and (2) FAST‐IRES provides accurate source estimation that is highly concordant with clinical ground truth, even in situations of single spike analysis with low signal‐to‐noise ratio.
Objective
The single‐center retrospective cohort study investigated underlying pathogenic mechanisms and clinical significance of patients with temporal lobe epilepsy and hippocampal sclerosis (TLE‐HS), in the presence/absence of gray–white matter abnormalities (usually called “blurring”; GMB) in ipsilateral temporopolar region (TPR) on MRI.
Methods
The study involved 105 patients with unilateral TLE‐HS (60 GMB+ and 45 GMB−) who underwent standard anterior temporal lobectomy, along with 61 healthy controls. Resected specimens were examined under light microscope. With combined T1‐weighted and DTI data, we quantitatively compared large‐scale morphometric features and exacted diffusion parameters of ipsilateral TPR‐related superficial and deep white matter (WM) by atlas‐based segmentation. Along‐tract analysis was added to detect heterogeneous microstructural alterations at various points along deep WM tracts, which were categorized into inferior longitudinal fasciculus (ILF), uncinate fasciculus (UF), and temporal cingulum.
Results
Comparable seizure semiology and postoperative seizure outcome were found, while the GMB+ group had significantly higher rate of HS Type 1 and history of febrile seizures, contrasting with significantly lower proportion of interictal contralateral epileptiform discharges, HS Type 2, and increased wasteosomes in hippocampal specimens. Similar morphometric features but greater WM atrophy with more diffusion abnormalities of superficial WM was observed adjacent to ipsilateral TPR in the GMB+ group. Moreover, microstructural alterations resulting from temporopolar GMB were more localized in temporal cingulum while evenly and widely distributed along ILF and UF.
Interpretation
Temporopolar GMB could signify more severe and widespread microstructural damage of white matter rather than a focal cortical lesion in TLE‐HS, affecting selection of surgical procedures.
Objectives: We comprehensively characterised a large paediatric cohort with histologically confirmed focal cortical dysplasia (FCD) type 1 to demonstrate the role of advanced multimodal pre-surgical evaluation and identify predictors of postsurgical outcomes.
Methods: This study comprised a systematic re-analysis of clinical, electrophysiological, and radiological features. The results of this re-analysis served as independent variables for subsequent statistical analyses of outcome predictors.
Results: All children (N = 31) had drug-resistant epilepsy with varying impacts on neurodevelopment and cognition (presurgical intelligence quotient (IQ)/developmental quotient scores: 32-106). Low presurgical IQ was associated with abnormal slow background electroencephalogram (EEG) activity and disrupted sleep architecture. Scalp EEG showed predominantly multiregional and often bilateral epileptiform activity. Advanced epilepsy magnetic resonance imaging (MRI) protocols identified FCD-specific features in 74.2% of patients (23/31), 17 of whom were initially evaluated as MRI-negative. In six out of eight MRI-negative cases, fluorodeoxyglucose positron emission tomography (FDG-PET) and subtraction ictal single-photon emission computed tomography co-registered to MRI (SISCOM) helped localise the dysplastic cortex. Sixteen patients (51.6%) underwent stereoelectroencephalography (SEEG). Twenty-eight underwent resective surgery, and three underwent hemispheral disconnection. Seizure freedom was achieved in 71.0% of patients (22/31) by the last follow-up, including seven of the eight MRI-negative patients. Anti-seizure medications (ASMs) were reduced in 21 patients, with complete withdrawal in 5 individuals. Seizure outcome was predicted by a combination of the following descriptors: age at epilepsy onset, epilepsy duration, long-term invasive EEG, and specific MRI, and PET findings.
Significance: This study highlights the broad phenotypic spectrum of FCD type 1, which spans far beyond the narrow descriptions of previous studies. Combining advanced MRI protocols with additional neuroimaging techniques helped localise the epileptogenic zone in many previously non-lesional cases. Complex multimodal presurgical approaches (including SEEG) could enhance postsurgical outcomes in these complex patients.
Patients with drug-resistant temporal lobe epilepsy often undergo intracranial EEG recording to capture multiple seizures in order to lateralize the seizure onset zone. This process is associated with morbidity and often ends in postoperative seizure recurrence. Abundant interictal (between-seizure) data are captured during this process, but these data currently play a small role in surgical planning. Our objective was to predict the laterality of the seizure onset zone using interictal intracranial EEG data in patients with temporal lobe epilepsy. We performed a retrospective cohort study (single-centre study for model development; two-centre study for model validation). We studied patients with temporal lobe epilepsy undergoing intracranial EEG at the University of Pennsylvania (internal cohort) and the Medical University of South Carolina (external cohort) between 2015 and 2022. We developed a logistic regression model to predict seizure onset zone laterality using several interictal EEG features derived from recent publications. We compared the concordance between the model-predicted seizure onset zone laterality and the side of surgery between patients with good and poor surgical outcomes. Forty-seven patients (30 female; ages 20–69; 20 left-sided, 10 right-sided and 17 bilateral seizure onsets) were analysed for model development and internal validation. Nineteen patients (10 female; ages 23–73; 5 left-sided, 10 right-sided, 4 bilateral) were analysed for external validation. The internal cohort cross-validated area under the curve for a model trained using spike rates was 0.83 for a model predicting left-sided seizure onset and 0.68 for a model predicting right-sided seizure onset. Balanced accuracies in the external cohort were 79.3% and 78.9% for the left- and right-sided predictions, respectively. The predicted concordance between the laterality of the seizure onset zone and the side of surgery was higher in patients with good surgical outcome. We replicated the finding that right temporal lobe epilepsy was harder to distinguish in a separate modality of resting-state functional MRI. In conclusion, interictal EEG signatures are distinct across seizure onset zone lateralities. Left-sided seizure onsets are easier to distinguish than right-sided onsets. A model trained on spike rates accurately identifies patients with left-sided seizure onset zones and predicts surgical outcome. A potential clinical application of these findings could be to either support or oppose a hypothesis of unilateral temporal lobe epilepsy when deciding to pursue surgical resection or ablation as opposed to device implantation.
To investigate health-related quality of life (HRQOL) in relation to seizure outcome as part of a multicenter follow-up of epilepsy surgery in Sweden.
A battery including the SF-36 Health Survey and the Hospital Anxiety and Depression scale (HAD) was distributed to all patients older than 16 years. Mean follow-up time was 4 years (range, 2-13 years) and response rate, 91% (103 of 113 patients). HRQOL data were related to seizure frequency and severity (Chalfont Seizure Severity Scale).
Seventy-six percent considered their global health to be better than it was before surgery. Degree of improvement in seizure control correlated with improved satisfaction with health (Spearman's r = 0.44). Higher SF-36 scores (higher HRQOL ratings) correlated with percentage reduction of seizure frequency for all scales and was strongest for perception of general health (Spearman's r = 0.46). When the patients were divided into four categories [A, completely seizure free (n = 29); B, seizure free with aura (n = 18); C, > or =75% reduction in seizure frequency (n = 24); and D, <75% reduction in seizure frequency (n = 32)], a strong positive association was found between higher SF-36 scores (with the exception of physical functioning) and better seizure control. Health-related limitations in role performance differentiated best between the outcome categories. For patients with > or =75% reduction in seizure frequency, low seizure severity correlated with higher HRQOL ratings for scales measuring social function, vitality, and mental health. Depression levels (HAD scale scores) were on average low. Anxiety (HAD) increased significantly from A to D.
HRQOL seems to be scored as a continuum in relation to seizure frequency. Seizure severity measures give complementary information.
Outcome measures Epilepsy: a comprehensive textbook
- At Berg
- Vickrey
- Engel
- Jr
- Pedley
Berg AT, Vickrey BG. Outcome measures. In: Engel J Jr, Pedley TA, eds. Epilepsy: a comprehensive textbook. Philadelphia: Lippincott-Raven, 1997:1891–9.
Progress in epilepsy research: long-term outcome after epilepsy surgery FIG. 1. Graphic display of Table 3. For reasons of clarity, class 6 is not plotted
- Ss Spencer
Spencer SS. Progress in epilepsy research: long-term outcome after epilepsy surgery. Epilepsia 1996;37:807–13. FIG. 1. Graphic display of Table 3. For reasons of clarity, class 6 is not plotted. COMMISSION ON NEUROSURGERY OF THE ILAE 286 Epilepsia, Vol. 42, No. 2, 2001
Defining new aims and providing new categories for measuring outcome of epilepsy surgery in children Paediatric epilepsy syndromes and their surgical treatment
- Dc Taylor
- Jh Cross
- W Harkness
- Bgr Neville
Taylor DC, Cross JH, Harkness W, Neville BGR. Defining new
aims and providing new categories for measuring outcome of epilepsy surgery in children. In: Tuxhorn I, Holthausen H, Boenigk H,
eds. Paediatric epilepsy syndromes and their surgical treatment.
London: John Libbey, 1997:17–25.
Defining new aims and providing new categories for measuring outcome of epilepsy surgery in children
- D C Taylor
- J H Cross
- W Harkness
- Bgr Neville
Taylor DC, Cross JH, Harkness W, Neville BGR. Defining new
aims and providing new categories for measuring outcome of epilepsy surgery in children. In: Tuxhorn I, Holthausen H, Boenigk H,
eds. Paediatric epilepsy syndromes and their surgical treatment.
London: John Libbey, 1997:17-25.