To identify clinically meaningful patterns in ictal electroclinical features of focal epilepsy using a data-driven, unsupervised learning approach, and to assess whether such patterns can localize and lateralize the epileptogenic zone (EZ) more accurately than conventional electroclinical interpretation. Ictal scalp EEG and seizure semiology were systematically extracted using the SCORE system in 116 patients with drug-resistant focal epilepsy who subsequently underwent resective surgery. Unsupervised clustering was applied separately to EEG and semiology features using k-means and agglomerative hierarchical clustering. Cluster quality was evaluated using the silhouette score, within-cluster sum of squares (WSS), between-cluster sum of squares (BSS), the ratio of between-cluster to within-cluster variance (BSS/WSS), the proportion of variance explained by clustering (BSS/TSS), and the Calinski-Harabasz index. The ability of the resulting clusters to localize and lateralize the temporal lobe EZ was assessed and compared with the conventional approach reflecting current clinical practice, based on previously published lateralizing signs, semiology localizing to the temporal lobe, and scalp EEG localization of ictal onset. Unsupervised clustering achieved strong structure for EEG and moderate for semiology data. K-means clustering of EEG features yielded a silhouette score of .63, while hierarchical clustering of semiology features achieved a silhouette score of .54. Semiology-based clusters showed substantial overlap with respect to both localization and lateralization. EEG-based clusters localized and lateralized the temporal lobe EZ with an accuracy of 65.3% (95% CI: 55.0%-74.6%). This performance was comparable to conventional electroclinical interpretation using scalp EEG ictal onset (68.1%, 95% CI: 57.5%-77.5%). Interpretation based on seizure semiology achieved an accuracy of 71.3% (95% CI: 61.0-80.1%). Unsupervised clustering of ictal electroclinical features did not outperform conventional expert interpretation in localizing or lateralizing the EZ. These findings suggest that the limitations may be inherent to the observable ictal phenomena captured by scalp EEG and semiology. Future research should focus on identifying novel or complementary biomarkers to improve precision in epilepsy surgery evaluation.

Knowledge in the spectrum of epidermal nevi and epidermal nevus syndrome has been elaborated on and expanded rapidly through the years. In this review, we provide a comprehensive overview of the neurologic manifestations of epidermal nevus syndromes (ENS), with a particular focus on epilepsy, which represents one of the most disabling and frequent systemic complications. Although ENS comprises a heterogeneous group of neurocutaneous syndromes unified by the presence of epidermal hamartomas and extracutaneous involvement, the relationship between genotype, cutaneous phenotype, and seizure phenotype remains incompletely understood. We systematically outline the epileptogenic potential of the 10 well-characterized ENS subtypes, highlighting the distinct seizure types, electroencephalographic findings, and associated structural brain anomalies such as hemimegalencephaly, cortical dysplasia, and neuronal heterotopias. Particular emphasis is placed on subtypes with a high seizure burden, including keratinocytic epidermal nevus syndrome, nevus sebaceus syndrome, phakomatosis pigmentokeratotica, nevus comedonicus syndrome, and angora hair nevus syndrome. For each, we examine the available evidence on seizure semiology, electroencephalographic correlates, radiologic features, and outcomes. Additionally, we review current management strategies, including both medical and surgical approaches to epilepsy in ENS, and discuss the emerging role of molecular targeted therapies. Through this review, we aim to underscore the importance of early diagnostic evaluation in patients presenting with epidermal nevi and to support multidisciplinary approaches for seizure control and long-term neurologic outcomes.

Objective: Many patients develop post-traumatic epilepsy (PTE). Post-traumatic epileptogenesis has been carefully studied in rodents, but the time course of epileptogenesis is correlated to brain size, raising the possibility that large animal models will provide more translatable data regarding epileptogenesis. Here, we use our large-brained model to describe the development, rate, and seizure semiology of PTE. Methods: Adult male and female swine received bilateral cortical impact (N=16) or sham surgery (N=9) and were screened for convulsions via video EEG for up to one year. PTE was defined as 2 seizures after 1 week post-injury. Results: Nine out of sixteen pig (56%) receiving bilateral cortical impact developed PTE, with an average latent period of 6.6 months (3.9, SD). Seizure began focally, sometimes with motor onset including automatisms (lip smacking, yawning) and sometimes nonmotor (freezing) before becoming generalized, with tonic-clonic or tonic convulsions. Most pigs had a period of post-ictal stillness (nonmotor) after the convulsions. Temporary incoordination occurred both pre- and post-ictal. We defined a library differentiating peri-ictal behaviors (N = 27) from rhythmic/odd behaviors typical in healthy pigs (N = 11). Pigs with PTE had an average of 5.6 behaviors per seizure, with a max of 22 behaviors in a seizure. The longest seizure was 7.9 minutes. For seizures comprised of multiple convulsive episodes, the first convulsion had a greater number of peri-ictal behaviors than subsequent convulsions (P < 0.02). The array of peri-ictal behaviors displayed was pig-specific, with many behaviors consistently observed across seizures. The overall seizure frequency was 0.43/day. Significance: This large-brain model of PTE exhibits a prolonged period of epileptogenesis, a substantial rate of PTE, and an expansive repertoire of ictal behaviors. This first description of semiology in this species will serve as a guide for other porcine epilepsy models. Biofidelic models of PTE are expected to increase our understanding of the pathophysiology of post-traumatic epileptogenesis and to identify and test therapeutics that translate into human patients.

Cortical evolutionary lineage as an organising principle for seizure semiology: implications for intracranial EEG and presurgical hypothesis generation.

Neurocysticercosis (NCC) remains a major cause of seizures in low- and middle-income countries, often progressing to chronic epilepsy due to calcified granulomas. The role of electroencephalographic (EEG) in predicting prognosis and guiding treatment in calcified NCC remains uncertain. The objective was to estimate the prevalence of surface EEG abnormalities in 5-18 years old seizure or epilepsy patients with single calcified neurocysticercosis lesion (CNL) and to understand the concordance of topographic anatomic localization to surface EEG abnormality localization, semiology localization. This cross-sectional study was performed in a tertiary care center in northern India. Children with epilepsy aged 5-18 years with single CNL on computed tomography (CT) scan were screened and those with seizure onset at least a year prior to recruitment and receiving standard of care for epilepsy were enrolled. The demographic profile, clinical details including seizure semiology, localization and lateralization, treatment history, CNL topography on CT scan, EEG findings and other relevant investigations were obtained. Out of the 366 pediatric patients screened, 61 cases were enrolled. EEG was performed on 60 patients. Focal seizures were most noted (88%, n = 53/60). Clinical localization was to frontal lobe (73.5%), temporal lobe (22.6%), parietal and occipital lobe in one patient each. EEG showed interictal discharges and or background EEG abnormalities in 48% (n = 29/60, 95% CI: 35%-61%). Interictal EEG abnormalities predominantly localized to frontal (86%, n = 25/29), parietal (7%, n = 2/29), and occipital (7%, n = 2/29) region. EEG and clinical semiology-based localization showed 78% crude agreement (P value - 0.02). Concordance between seizure semiology localization and anatomic localization on CT was 80% (P value- 0.0009). There was significant concordance between clinical, electrical, and radiological localization of CNL. Frontal and temporal lobe were most common symptomatic zones for focal epilepsy in this cohort.

A systematic review of the ictal semiology of fronto-opercular seizures in focal epilepsy was carried out to assess possible anatomical-clinical correlations and help guide interpretation of ictal semiology during pre-surgical evaluation. PubMed and Embase databases were searched using the following keywords: "fronto-opercular OR frontal opercular OR Frontal operculum OR superior perisylvian OR anterior opercular AND (epilep* or seizure)." The date last searched was November 30th, 2025. Studies were selected if they concerned case series, including at least one fully documented patient and informative case reports with the following criteria: patients who underwent a resection limited to the fronto-opercular cortex, and/or patients for whom the epileptogenic zone (EZ) was proven by intracranial electroencephalogram (iEEG) with insular cortex exploration, and/or by complementary noninvasive explorations. A total of 21 patients with fronto-opercular epilepsy from 16 studies were included in the review. iEEG was performed in 15 (71%) patients and resection in 16 (76%) patients. The confidence level in the EZ was very high (Engel IA) for 5 patients, high (Engel I not specified IA or Engel IB) for 12 patients, and moderate for 4 patients. The presence of an aura was found in 67% (n = 14/21) of the patients with mainly non-painful somatosensory sensations. This was more frequent in patients with an EZ in the precentral Rolandic operculum compared to those with an EZ in the prefrontal operculum (n = 6 versus n = 1, respectively, p = 0.016). Ictal signs comprised elementary motor symptoms, speech dysfunction, complex motor behavior, respiratory symptoms, salivation, and laughter, with preserved consciousness. Pure fronto-opercular epilepsy is rare, consisting mainly of contralateral elementary sensory aura especially for the Rolandic operculum. Common ictal signs are motor orofacial and brachial symptoms with preserved consciousness. Further studies including patients who underwent a successful resection limited to the frontal operculum are needed to confirm these anatomical-clinical correlations.

Arterial spin labeling in pediatric epilepsy in the emergency setting: clinical predictors of diagnostic yield and optimal acquisition time.

Genetic epilepsies include a broad spectrum of disorders caused by pathogenic variants in more than 1,000 genes. Their clinical expression is highly variable, making early phenotype-genotype interpretation challenging. Early seizure semiology and EEG features may offer clinically useful information for diagnostic orientation and management. The aim of this study was to characterize early clinical and EEG features in patients with genetic epilepsies, examine their associations with outcomes, and explore genotype-phenotype groupings through hierarchical clustering analysis (HCA). We conducted a retrospective study at Bambino Gesù Children's Hospital. Eligible participants carried pathogenic or likely pathogenic variants in epilepsy-related genes, identified through medical records and laboratory diagnostic logs. Clinical variables at seizure onset and EEG recordings performed within the first month of the initial seizure were extracted. Follow-up outcomes included seizure frequency, drug resistance, movement disorders, behavioral/autism spectrum disorder comorbidities, and developmental delay/intellectual disability (DD/ID). Associations between early features and outcomes were assessed using χ2 or Fisher tests. HCA was used to identify clusters linking early phenotype and gene-level etiology. We included 277 patients (52.3% female; median age at last follow-up 8.1 years, range 0-40). Drug resistance occurred in 58.8% and severe DD/ID in 35.4% of patients. EEG data at onset were available for 107 individuals. Neonatal onset was associated with a higher rate of drug resistance (71.4%; odds ratio [OR] 2.0, 95% CI 1.05-3.77), movement disorders (60.7%; OR 3.7, 95% CI 2.02-6.82), and severe DD/ID (71.4%; OR 7.0, 95% CI 3.66-13.49). Slow EEG background activity and multifocal epileptiform discharges were associated with both drug resistance and severe DD/ID. HCA identified genotype-phenotype groupings, including clusters involving SCN1A, PRRT2, STXBP1, KCNQ2, SCN2A, CHD2, SYNGAP1, and MECP2, each linked to specific clinical and EEG features. Early clinical and EEG features showed meaningful associations with outcomes and mapped onto specific genetic etiologies. HCA revealed coherent genotype-phenotype clusters that may support early diagnostic reasoning. Limitations include the retrospective design and small numbers per gene, warranting larger multicenter studies for validation.

To identify correlations between thalamic electroencephalographic (EEG) signal patterns and clinical seizure semiology in pediatric patients with drug-resistant epilepsy (DRE) treated with responsive neurostimulation (RNS). We conducted a retrospective analysis of 14 pediatric patients (≤17 years old) with DRE who received thalamic RNS implants. EEG recordings from the RNS Patient Data Management System were reviewed and correlated with seizure semiology obtained from medical records and structured family interviews. Patterns between seizure types, EEG onset signals, and electrode placement were examined. Absence seizures were associated with bilateral 3 Hz delta spike-wave complexes in the centromedian (CM) nucleus. Drop seizures corresponded with bilateral hypersynchronous slow-to-fast gamma activity, primarily in patients with CM or anterior nucleus leads. Generalized tonic-clonic seizures exhibited the greatest variability, with gamma-to-delta transitions, synchronous gamma waves, or asynchronous slow-to-gamma patterns depending on whether leads were placed in the CM or pulvinar nuclei. These EEG patterns were consistent within nuclei, suggesting semiology-specific thalamic activity. This study demonstrates that seizure onset EEG signals are nucleus- and semiology-specific in pediatric patients receiving thalamic RNS therapy. These findings highlight the CM nucleus's central role in seizure propagation and support individualized RNS programming based on EEG frequency signatures. While limited by sample size, this work provides early evidence that thalamic EEG biomarkers can inform more precise neuromodulation strategies for pediatric DRE.

In temporal lobe epilepsy (TLE), the amygdala in the epileptogenic network is underestimated compared to other regions such as the hippocampus. Recent advances in anatomical neuroimaging and stereoelectroencephalography (SEEG) signal analyses could help better understand the involvement of the different amygdala nuclei in the genesis of temporal lobe seizures. We retrospectively included 51 patients suffering from TLE who underwent SEEG over the past 5 years. The Virtual Epileptic Patient atlas with an integrated amygdala atlas was used to automatically localize SEEG contacts within the brain regions, including 9 amygdala nuclei. The Epileptogenicity Index (EI) and Connectivity Epileptogenicity Index (cEI) were computed on ictal SEEG recordings. We used a beta mixed model to evaluate the relative effects of amygdala nuclei, TLE subtypes, and lateralization of the epileptogenic zone on the epileptogenicity. We used the Wilcoxon rank sum test to study the associations between epileptogenicity level of distinct amygdala nuclei and ictal semiology (sensory, affective, cognitive, motor, and autonomic). We observed higher epileptogenicity within the basolateral (BL) nucleus compared to other nuclei of the basolateral complex (lateral (LA), accessory basal (BM), and paralaminar (PL) nuclei) across all TLE subtypes. Regarding semiology, BL was more epileptogenic in patients with sensory phenomena and LA in patients with autonomic phenomena, while PL was less epileptogenic in patients with cognitive phenomena. Our findings disentangle the different epileptogenicity of amygdala nuclei in temporal lobe seizures. The observed epileptogenicity variance across amygdala nuclei can be explained by underlying neuronal and cytoarchitectural substrates. ANN NEUROL 2026.

Electroclinical features and surgical outcomes in cingulate epilepsy - A single- centre experience.

Pediatric functional seizures: Demographics, clinical and psychological characteristics and risk factors.

To generate a behavioral feature library for a more granular description of seizure semiology in rats with traumatic brain injury (TBI). To compare the new approach to the Racine score. A library of 59 seizure-related behavioral features was generated by annotating 329 seizures in 31 rats with TBI, which were monitored using high-resolution video-electroencephalogram. Of the 329 seizures, 149 were early, 85 post-electrode implantation (6th post-injury month), and 95 late seizures (7th post-injury month). Of the 59 behavioral features, 3 were pre-ictal, 43 ictal, and 13 post-ictal. Of the 43 ictal features, 7 related to consciousness, 5 to mouth and whiskers, 2 to eyes, 7 to head, 2 to ears, 6 to paws, 12 to body and tail, 2 to autonomic function, and 1 to wet-dog shakes. Early, post-implantation, and late seizures showed different behavioral phenotypes (p < 0.001). The number of behavioral features in post-electrode implantation and late seizures was greater than that in early seizures (p < 0.05). Behavioral features did not reliably differentiate transitions from pre-ictal to ictal or from ictal to post-ictal phases. Ninety-one percent of early, 45 % of post-electrode implantation, and 18 % of late seizures with a Racine score of 0 showed up to 6-7 ictal-related behaviors. The Proposed feature list can be applied for the harmonization of data analysis and reporting, and training of video-based seizure detection algorithms to speed up non-invasive, affordable epilepsy diagnosis and assessment of treatment effects in TBI models.

Male people with epilepsy (mPWE) are at higher risk for bilateral tonic-clonic seizures (BTCs) and sudden unexpected death in epilepsy (SUDEP) compared to female people with epilepsy (fPWE). Despite major clinical and personal implications, little is known about sex-specific differences in seizure propagation and termination. Characterization of seizure duration in men versus women with unifocal epilepsy. Adults with unifocal epilepsy and available intracranial EEG (iEEG) recordings (September 2006 to March 2022) were identified retrospectively. Up to 20 clinical seizures were analyzed per person, excluding individuals with status epilepticus or lateralized periodic discharges. Seizure duration was determined based on iEEG recordings. In focal to bilateral tonic-clonic seizures (FBTCs), durations of the focal and BTC phases were assessed based on EEG and seizure semiology. Multiple linear regression was used to assess sex-specific differences in seizure duration, adjusting for age, epileptic hemisphere, frontal lobe epilepsy (FLE), temporal lobe epilepsy (TLE), lateralizing signs, onset during sleep, and focal seizures with preserved consciousness and aura phenomena (FPC-a). A restricted-cohort sensitivity analysis was performed, excluding PWE in whom clinical seizure onset preceded iEEG onset. A total of 100 PWE (m/f = 50/50; age: 33.6 ± 12.2 years) and 758 seizures (120 FBTCs) were analyzed. While fPWE had significantly longer focal seizures (FSs) (p = 0.015), mPWE revealed significantly longer FBTCs (p < 0.001), driven by a prolonged focal phase (p = 0.002). No significant difference was observed for the BTC phase. In the restricted cohort (n = 77 PWE), the prolongation of the focal phase during FBTCs in mPWE remained robust (p = 0.006). Our findings demonstrate sex-specific differences in seizure duration, suggesting that seizure propagation may differ between men and women. This may contribute to a better pathophysiological understanding of the sex-specific differences in seizure manifestation and associated risks and underline the yet unmet need for a sex-specific approach in epilepsy research and patient management. Sex-related differences in epilepsy are increasingly recognized but remain poorly understood. In this study, we compared seizure duration between women and men with unifocal epilepsy using intracranial brain recordings. We found that women had longer focal seizures, whereas men had longer focal phases in focal to bilateral tonic-clonic seizures. Further research is needed, as these differences may be relevant for clinical care and risk assessment in epilepsy.

Infants aged 1-24 months with new onset epilepsy frequently present with structural brain abnormalities, yet no updated evidence-based magnetic resonance imaging (MRI) guidelines exist for this population. The International League Against Epilepsy (ILAE) Neuroimaging Task Force developed evidence-based recommendations for structural brain MRI in infants with a first afebrile seizure or new onset epilepsy. A multidisciplinary panel defined three PICO (patients, intervention, comparison group, outcome under consideration) questions, conducted a systematic review (PROSPERO [Prospective Register of Systematic Reviews] CRD42024592653), and reported the results in line with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) 2020 guidelines. Risk of bias was evaluated using the JBI (Joanna Briggs Institute) checklist. GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) methodology was used to assess certainty of evidence and formulate recommendations for the following: (1) the effectiveness of MRI in identifying underlying etiologies, (2) clinical predictors of MRI abnormalities, and (3) MRI protocols. Seventeen studies (n = 1209) were included. Among 753 infants who underwent MRI, 438 (58.2%) had abnormal findings. Despite heterogeneity in MRI protocols and reporting, the evidence supports the utility of MRI in this population. Specific clinical features (focal seizure semiology, abnormal neurological examination, seizure duration > 5 min, focal electroencephalographic abnormalities, developmental delay, and perinatal complications) were associated with abnormal MRI findings, although methodological limitations reduce certainty. Only six studies provided data on MRI sequences; however, none reported findings specifically in relation to the diagnostic accuracy or yield of individual protocols, precluding the development of evidence-based recommendations on MRI protocol selection. MRI is conditionally recommended in all infants with a first afebrile seizure or new onset epilepsy. MRI could be prioritized in those with specific clinical features indicative of higher likelihood of abnormal findings. Recommendations are based on very low certainty of evidence. These are the first ILAE-endorsed, evidence-based recommendations for MRI in infants with first afebrile seizure or new onset epilepsy. Further prospective studies with standardized protocols are needed to refine MRI indications and optimize diagnostic yield in this age group.

To evaluate the ictal semiology in seizures originating in the precuneus and to help guide seizure interpretation within the framework of presurgical evaluation. This systematic review followed a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and a Quality Assessment tool for Diagnostic Accuracy Studies (QUADAS2) based approach. We searched PubMed and Embase with keywords related to the precuneus, parietal or posterior epilepsy, video-EEG, and epilepsy surgery. Included studies report patients with seizures originating in the precuneus and video-EEG-based description of seizure symptoms. Screening and data extraction of all studies were performed by two independent reviewers. The summary of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Nine studies reporting 29 patients were included in the final analysis. The most common symptoms at the onset of seizures were vestibular symptoms, visual illusions and hallucinations, and body perception illusions. Motor symptoms were either elementary or complex motor phenomena that emerged during seizure propagation. However, the overall quality of evidence remained moderate or low. This systematic review suggests typical seizure symptoms associated with precuneus seizures. However, it also shows a paucity of reports on precuneus seizures. Larger prospective studies with more detailed anatomo-electro-clinical data are needed to better understand seizures with precuneal origin within the entity of posterior cortex seizures.

To investigate the frequency, predictors, and clinical implications of diagnostic reassessment in patients previously diagnosed with childhood-onset epilepsy during the transition period to adult care at a tertiary epilepsy center. We conducted a retrospective cohort study of 317 patients previously diagnosed with childhood-onset epilepsy who underwent diagnostic reassessment between April 2018 and December 2023 at age 16 years or older at a tertiary epilepsy center in Japan. Diagnostic revision was defined as a newly established or corrected epilepsy/epilepsy syndrome diagnosis, identification of structural or genetic/metabolic etiologies, or diagnosis of non-epileptic conditions. Univariate and multivariate logistic regression analyses were performed to identify independent predictors of diagnostic revision. A new or revised diagnosis was established in 60 of the 317 patients (18.9%). Independent predictors of diagnostic revision included exclusively non-motor seizures (adjusted odds ratio [aOR] = 7.610; 95% confidence interval [CI]: 2.660-21.767; p < 0.001) and weekly or monthly seizure frequency (aOR = 3.370; 95% CI: 1.265-8.976; p = 0.015), whereas prior visits to other epilepsy centers were strongly protective (aOR = 0.047; 95% CI: 0.015-0.146; p < 0.001). Sensitivity analyses yielded consistent results. Newly identified etiologies include focal cortical dysplasia, hippocampal sclerosis, and pathogenic genetic variants such as CDKL5, PCDH19, and SYNGAP1. Diagnostic reassessment facilitated antiseizure medication withdrawal in patients with self-limited epilepsy and non-epileptic events. Nearly one in five patients previously diagnosed with childhood-onset epilepsy required diagnostic revision during the transition to adult care. Non-motor seizure semiology and moderate seizure frequency were the major predictors of diagnostic revision, highlighting the diagnostic uncertainty associated with subtle clinical presentations. These findings highlight that systematic reassessment, especially for individuals who have not previously undergone specialized epilepsy center evaluation, is essential for achieving an accurate diagnosis and optimizing management in adulthood. Many people diagnosed with epilepsy in childhood continue medical care into adulthood, but their diagnosis may need to be reviewed later in life. In this study, nearly one in five patients who had been diagnosed with childhood-onset epilepsy required a change or refinement of their diagnosis when reassessed after age 16. Patients with seizures without clear physical movements and those whose seizures occurred weekly or monthly were more likely to need diagnostic review. These findings highlight the importance of reviewing the diagnosis during adolescence, especially for patients who have not previously been evaluated at specialized epilepsy centers.

Abstract Background and Objectives Muscle‐Eye‐Brain disease (MEB) is a dystroglycanopathy that belongs to the congenital muscular dystrophies. Central nervous system manifestations include congenital brain abnormalities, neurodevelopmental delay, and epilepsy, making it a rare but important cause of developmental and epileptic encephalopathy. This systematic review aims to explore all current literature data regarding clinical and electroencephalographic features of MEB cases with epilepsy. Materials and Methods We conducted a literature review of previously published cases of patients with MEB and epilepsy in the PubMed and Scopus databases in the English language, focusing on seizure semiology and electroencephalographic features. Results We included 52 studies with 80 patients. The clinical spectrum of patients with MEB is broad, including hypotonia at birth, ocular symptoms, delay of motor milestones, and intellectual disability. Serum creatine kinase levels are significantly elevated (median value 1600 IU/L). POMGnT1 mutation is, by far, the most common mutation in MEB patients, reported in 38.8% of cases, followed by GMPPB (10%), FKTN, POMT2, or DPM2 mutations (less than 10%, respectively). Epilepsy is a common feature, with onset usually in the first 6 months of life. Absences are the most common seizure type (58.8% of patients), followed by generalized tonic–clonic (33.8%) and focal seizures (21.3%). Patients present with drug‐resistant epilepsy in approximately one fourth of cases (21.3%). Electroencephalogram (EEG) shows focal or multifocal discharges in approximately half of the cases, with a predominance over frontal or temporal regions. Slow and disorganized EEG background activity is commonly observed in 92.9% of cases. Conclusion Epilepsy is a common feature in MEB patients; its age of onset is usually in the first months of life, and it is often drug‐resistant. It can manifest with all seizure types, with absences being the most common type. EEG shows focal or multifocal discharges with a slow and disorganized EEG background. The POMGnT1 mutation is the most common in MEB patients with epilepsy. A clear understanding of the electroclinical patterns in MEB patients can contribute to improved diagnostic precision and management.

Epileptic seizures in cats and dogs are etiologically classified as idiopathic epilepsy, structural epilepsy and reactive seizures, and semiologically as atonic, tonic/clonic, or generalized tonic clonic, focal and focal seizures evolving into generalized seizures. This retrospective study aimed to evaluate the semiological patterns and etiological causes of seizures in both species, and to assess interspecies differences in a regional veterinary population. Between January 2022 and January 2025, 77 cats and 106 dogs presented with seizures to Ondokuz Mayis University Animal Hospital (Samsun/Turkiye). After exclusions due to insufficient data or financial constraints, 24 cats and 29 dogs were included based on the Tier-I diagnostic criteria proposed by the International Veterinary Epilepsy Task Force. The relationships between species, age, sex, neuter status, seizure semiology and etiology were analyzed. Generalized tonic-clonic seizures were observed in 83.3% of cats and 72.4% of dogs. Idiopathic epilepsy was diagnosed in 41.7% of cats and 55.2% of dogs. Structural epilepsy in cats was mainly associated with feline infectious peritonitis, while canine distemper virus was the predominant cause in dogs. Although seizure types were broadly similar across species, some etiological differences appeared regionally. The high rate of generalized seizures may reflect observer bias or challenges in accurately classifying semiology without electroencephalography. This study highlights the utility of tiered diagnostic approaches in veterinary epileptology and underscores the need for updated, species-specific consensus guidelines for diagnostic approach and classification especially in feline patients.

PTEN Hamartoma Tumor Syndrome (PHTS) is an autosomal dominant syndrome caused by a mutation in the PTEN gene. Previous studies have suggested an association between PHTS and epilepsy, but the clinical characteristics of epilepsy in PHTS remain unknown. This study aims to expand knowledge of epilepsy in PHTS and provide insights into its clinical features. A retrospective observational study was conducted at the Radboud University Medical Center, including 149 patients with clinically or genetically confirmed PHTS. Electronic patient records were reviewed for baseline characteristics, epileptic features, therapeutic interventions, and neuroimaging results. A cumulative risk analysis for developing epilepsy was performed. The prevalence of epilepsy among PHTS patients in this cohort was found to be 6%, with an estimated PHTS prevalence of 1:20000 in the Netherlands. Autism spectrum disorder (ASD) was significantly associated with an increased risk of developing epilepsy (p=0.002). A range of seizure semiologies was observed, with focal epilepsy being the most common, presenting as focal seizures with impaired awareness. EEG results predominantly showed (multi)focal discharges with variable localization. MRI abnormalities did not correlate with epileptic foci on EEG. This study highlights the clinical characteristics of epilepsy in pediatric patients with PHTS. Follow-up should include monitoring for characteristics of focal epilepsy, with EEG utilized selectively when such episodes are observed, rather than as a routine screening measure. Treatment strategies should be individualized based on the patient's characteristics. In cases of epilepsy, MRI is recommended to identify potential structural malformations amenable to surgical intervention.