Caraballo, Roberto

Abstract Objective Invasive presurgical evaluation plays a key role in pediatric epilepsy surgery, particularly in magnetic resonance imaging (MRI)‐negative cases, by guiding resective, disconnective, or ablative procedures. This International League Against Epilepsy (ILAE) Pediatric Epilepsy Surgery Taskforce study provides an updated global overview of current invasive evaluation practices. Methods Group‐level data were collected from 61 epilepsy surgery programs (49 pediatric‐only) in 29 countries across six continents. Included were children and adolescents who underwent presurgical evaluation and epilepsy surgery in 2023. The study was designed to enable comparison with the similar ILAE survey conducted in 2004. Results A total of 2427 patients were included. Invasive evaluations were performed in 21.1% of cases, most frequently in North America (33.7%, higher than Europe: 18.0%, p = .003). Among invasive cases, 32.3% had no detectable MRI abnormalities. The main indication for invasive evaluation was seizure onset localization (88.1%), followed by motor or sensory mapping (17.2%) and language mapping (14.2%). Stereoelectroencephalography (SEEG) was the predominant technique (19.8% overall, 93.6% of invasive cases), more common in North America (30.0%, p = .021) and less common in South America (7.4%, p < .001). Subdural electrodes were used in only 3.2% of invasive cases, and combined depth and subdural approaches in 3.2%. SEEG‐guided radiofrequency thermocoagulation (RF‐TC) was performed in 40.9% of SEEG cases, most commonly in Asia (63.8%). In 16.2% of invasive evaluations, patients did not proceed to resection, disconnection, or ablation, with the highest rate in Europe (28.5%). Significance This global survey provides the first broad overview of invasive evaluation practices in pediatric epilepsy surgery across participating centers worldwide. It highlights the widespread adoption of SEEG, declining use of subdural electrodes, and increasing application of SEEG‐guided RF‐TC. The high proportion of MRI‐negative cases and the considerable proportion of patients not proceeding to resection, disconnection, or ablation underscore the complexity of contemporary surgical candidates and the need for further refinement of selection strategies.

Abstract Objective Pediatric epilepsy surgery is well established, but contemporary global data on referral and presurgical evaluation practices are lacking. This International League Against Epilepsy (ILAE) Pediatric Epilepsy Surgery Task Force study provides an updated overview of current trends and regional differences. Methods Group‐level data were collected from 61 epilepsy surgery programs (49 pediatric‐only) across 29 countries and six continents, identified through ILAE networks, and included all children and adolescents treated in 2023 who underwent presurgical evaluation/epilepsy surgery. Results Group‐level data were available for 2427 patients. Mean age at surgery was 9.1 ± 4.9 years; mean epilepsy duration was 5.3. At surgery, 3.2% were <1 year old (highest in Oceania: 5.1%), and 6.1% were nonpharmacoresistant (highest in Europe: 15.0%). Prior neurosurgery was reported in 14.2% (highest in North America: 28.8%), including 8.0% resections (6.1% for epilepsy, 1.5% for tumors; highest in Oceania: 16.5%), 2.3% disconnections (1.3% corpus callosotomy; highest in South America: 4.7%), and 4.2% neuromodulation (3.7% vagal nerve stimulation, .2% responsive neurostimulation, one deep brain stimulation; highest in North America: 12.2%). Developmental and epileptic encephalopathies (DEEs) at surgery included Lennox–Gastaut syndrome (7.4%), infantile epileptic spasms syndrome (5.1%), and DEE with spike–wave activation in sleep (1.5%). Presurgical investigations included fluorodeoxyglucose positron emission tomography (52.6%; highest in Oceania: 79.7%), genetic testing (46.8%; highest in Asia: 54.3%), magnetic resonance imaging (MRI) postprocessing (32.4%; highest in South America: 53.0%), functional MRI (fMRI; 15.2%; highest in North America: 40.3%), magnetoencephalography (11.9%; highest in North America: 39.3%), single photon emission computed tomography (9.6%; highest in North America: 22.2%), high‐density electroencephalography (EEG; 1.9%; highest in Europe: 4.7%), source localization (1.6%; highest in Oceania: 7.6%), Wada test (1.2%; highest in North America: 3.5%), and EEG‐fMRI (.5%; highest in Europe: 1.1%). Significance Despite some early surgeries, including in infancy and before pharmacoresistance, mean epilepsy duration before surgery remains >5 years. Reoperations are common, with resection more frequent than neuromodulation. Genetic testing in nearly half of patients reflects its growing relevance, and the high rate of DEEs underscores the complexity of surgical candidates.

Abstract The International League Against Epilepsy (ILAE) has updated the operational classification of epileptic seizures, building upon the framework established in 2017. This revision, informed by the implementation experience, involved a working group appointed by the ILAE Executive Committee. Comprising 37 members from all ILAE regions, the group utilized a modified Delphi process, requiring a consensus threshold of more than two thirds for any proposal. Following public comments, the Executive Committee appointed seven additional experts to the revision task force to address and incorporate the issues raised, as appropriate. The updated classification maintains four main seizure classes: Focal, Generalized, Unknown (whether focal or generalized), and Unclassified. Taxonomic rules distinguish classifiers, which are considered to reflect biological classes and directly impact clinical management, from descriptors, which indicate other important seizure characteristics. Focal seizures and those of unknown origin are further classified by the patient's state of consciousness (impaired or preserved) during the seizure, defined operationally through clinical assessment of awareness and responsiveness. If the state of consciousness is undetermined, the seizure is classified under the parent term, that is, the main seizure class (focal seizure or seizure of unknown origin). Generalized seizures are grouped into absence seizures, generalized tonic–clonic seizures, and other generalized seizures, now including recognition of negative myoclonus as a seizure type. Seizures are described in the basic version as with or without observable manifestations, whereas an expanded version utilizes the chronological sequence of seizure semiology. This updated classification comprises four main classes and 21 seizure types. Special emphasis was placed on ensuring translatability into languages beyond English. Its aim is to establish a common language for all health care professionals involved in epilepsy care, from resource‐limited areas to highly specialized centers, and to provide accessible terms for patients and caregivers.

ABSTRACTThe concept of epilepsy syndromes, introduced in 1989, was defined as “clusters of signs and symptoms customarily occurring together”. Definition of epilepsy syndromes based on electro‐clinical features facilitated clinical practice and, whenever possible, clinical research in homogeneous groups of patients with epilepsies. Progress in the fields of neuroimaging and genetics made it rapidly clear that, although crucial, the electro‐clinical description of epilepsy syndromes was not sufficient to allow much needed development of targeted therapies and a better understanding of the underlying pathophysiological mechanisms of seizures. The 2017 ILAE position paper on Classification of the Epilepsies recognized that “as a critical tool for the practicing clinician, epilepsy classification must be relevant and dynamic to changes in thinking”. The concept of “epilepsy syndromes” evolved, incorporating issues related to aetiologies and comorbidities. A comprehensive update (and revision where necessary) of the EEG diagnostic criteria in the light of the 2017 revised terminology and concepts was deemed necessary. Part 2 covers the neonatal and paediatric syndromes in accordance with the age of onset. [Published with educational EEG plates atwww.epilepticdisorders.com].

AbstractRational. The concept of epilepsy syndromes, introduced in 1989, was defined as “clusters of signs and symptoms customarily occurring together”. Definition of epilepsy syndromes based on electro‐clinical features facilitated clinical practice and, whenever possible, clinical research in homogeneous groups of patients with epilepsies. Progress in the fields of neuroimaging and genetics made it rapidly clear that, although crucial, the electro‐clinical description of epilepsy syndromes was not sufficient to allow much needed development of targeted therapies and a better understanding of the underlying pathophysiological mechanisms of seizures. The 2017 ILAE position paper on Classification of the Epilepsies recognized that “as a critical tool for the practicing clinician, epilepsy classification must be relevant and dynamic to changes in thinking”. The concept of “epilepsy syndromes” evolved, incorporating issues related to aetiologies and comorbidities. A comprehensive update (and revision where necessary) of the EEG diagnostic criteria in the light of the 2017 revised terminology and concepts was deemed necessary.Methods. The work was commissioned by the Neurophysiology Task Force of the ILAE Committee on the Diagnostic Methods. Diagnostic criteria and recording procedures were developed by group consensus, reached through an “informal”, internal decision‐making process. Each working group member was allocated a number of syndromes, and a standard structured template was used. International literature was extensively reviewed.Results. We developed a simple diagnostic system that is applicable to all epilepsy syndromes which allows the physician (i) to rate the strength of EEG diagnosis (degree of diagnostic certainty) by weighting EEG findings in relation to the available clinical information or the specific clinical question, and ii) to suggest further EEG diagnostics where conclusive diagnostic evidence is lacking. We also propose a system of syndrome‐specific recording protocols that, used with the relevant clinical presentation or specific clinical question, may maximize activation of epileptic discharges and ultimately help with standardization of EEG recording across departments, worldwide. Because recording methodology also depends on available resources, a two‐tier system was developed to embrace clinical EEG services in resource‐limited and industrialized countries. A clinical practice statement for each of the epilepsy syndromes discussed underscores the crucial role of the clinical information with regards to both the optimization of the EEG recording and mainly its meaningful interpretation. Part I covers Genetic (Idiopathic) generalized epilepsies and syndromes, Reflex epilepsies, structural and genetic focal (lobar) syndromes and Progressive Myoclonus Epilepsies [Published with educational EEG plates on www.epilepticdisorders.com].

Summary Ketogenic dietary therapies ( KDTs ) are established, effective nonpharmacologic treatments for intractable childhood epilepsy. For many years KDTs were implemented differently throughout the world due to lack of consistent protocols. In 2009, an expert consensus guideline for the management of children on KDT was published, focusing on topics of patient selection, pre‐ KDT counseling and evaluation, diet choice and attributes, implementation, supplementation, follow‐up, side events, and KDT discontinuation. It has been helpful in outlining a state‐of‐the‐art protocol, standardizing KDT for multicenter clinical trials, and identifying areas of controversy and uncertainty for future research. Now one decade later, the organizers and authors of this guideline present a revised version with additional authors, in order to include recent research, especially regarding other dietary treatments, clarifying indications for use, side effects during initiation and ongoing use, value of supplements, and methods of KDT discontinuation. In addition, authors completed a survey of their institution's practices, which was compared to responses from the original consensus survey, to show trends in management over the last 10 years.