Stereoelectroencephalography (SEEG) is the gold standard to investigate the epileptic network in cases of drug-resistant epilepsy. Robot-assisted SEEG is increasingly being used; however, its installation process in the operating room is more difficult than that of the stereotactic frame procedure. New robotic tools and 3D intraoperative imaging ease the setup while achieving the same mechanical precision and a lower complication rate. In this video, the authors illustrate the surgical technique and step-by-step workflow using a robotic arm (neuromate) guided by a frameless registration system (neurolocate), registered with an intraoperative flat-panel CT scanner (O-arm). The video can be found here: https://stream.cadmore.media/r10.3171/2024.4.FOCVID2419.

Hypothalamic hamartomas are congenital lesions of the hypothalamus, with a range of symptoms defined by lesion location. Common presenting symptoms include gelastic seizures and precocious puberty. When hamartoma-related seizures become resistant to medications, laser interstitial thermal therapy (LITT) has been shown to be an effective treatment. The authors present a case of robot-assisted LITT for a patient with an 11-year history of epilepsy due to hypothalamic hamartoma. In addition, they demonstrate the use of a stereotactic biopsy needle implemented during the procedure for possible biopsy of deep cranial lesions. The video can be found here: https://stream.cadmore.media/r10.3171/2024.4.FOCVID2415.

An accurate definition of the epileptogenic zone is critical to the success of epilepsy surgery. When noninvasive presurgical studies are insufficient, stereoelectroencephalography (SEEG) becomes indispensable. This study illustrates a systematic approach using an illustrative case of centroparietal epilepsy, detailing the stepwise workup, planning, and image-guided robot-assisted frameless stereotactic implantation of intracerebral electrodes. The video provides insights into technical aspects and a single-center experience. Demonstrating efficacy, safety, and feasibility, SEEG emerges as a valuable procedure for studying drug-resistant focal epilepsy. The video can be found here: https://stream.cadmore.media/r10.3171/2024.4.FOCVID2427.

Vagus nerve stimulation (VNS) is a neuromodulatory treatment involving chronic intermittent electrical stimulation of the left vagus nerve, administered through a programmable pulse generator implanted subcutaneously in the chest. This generator connects to a bipolar lead, with electrodes wrapped around the vagus nerve in the neck. Primarily used as an adjunct therapy for patients with refractory epilepsy who cannot undergo or have not benefitted from resective surgery, VNS is generally well tolerated with few severe side effects. Herein is presented an educational surgical video providing a detailed, step-by-step technical description of VNS implantation. The video can be found here: https://stream.cadmore.media/r10.3171/2024.4.FOCVID244.

OBJECTIVE: To report the effects of adjunctive cenobamate and concomitant antiseizure medications (ASMs) on weight from two double-blind, placebo-controlled, phase 2 studies (YKP3089C013 [C013] and YKP3089C017 [C017]) and their open-label extensions (OLEs) and from a long-term, open-label phase 3 safety study, YKP3089C021 (C021).
BACKGROUND: Cenobamate is an ASM approved in the US and EU for treatment of focal seizures in adults. Some ASMs are associated with weight gain (e.g., valproate, gabapentin, pregabalin), which can negatively affect patient health.
METHODS: Patients with uncontrolled focal seizures taking stable doses of 1-3 ASMs were enrolled in each study. In C013, cenobamate was titrated to a target dose of 200 mg/day (max OLE dose 400 mg/day). In C017, patients were randomized to cenobamate 100, 200, or 400 mg/day (max OLE dose 400 mg/day). In C021, cenobamate was titrated to a target dose of 200 mg/day (max dose 400 mg/day). Median weight changes at 1 and 2 years from baseline were analyzed post hoc.
RESULTS: Analyses included 39, 206, and 1054 patients from C013, C017 (dose groups combined), and C021, respectively. Median weight changes from baseline ranged from -0.2 to -0.9 kg at 1 year and from -1.0 to +1.0 kg at 2 years. Some numerical reductions in weight were noted in patients who discontinued valproate by 1 (-13.0 kg, C013, n=1) or 2 years (-24.5 kg, C017, n=2) and in patients who discontinued gabapentin by 1 (-7.1 kg, C017, n=2) or 2 years (-7.0 kg, C017, n=2). Otherwise, median weight changes from baseline for patients receiving concomitant valproate, gabapentin, or pregabalin ranged from -3.1 to +2.6 kg at 1 year and from -1.6 to +2.7 kg at 2 years.
CONCLUSIONS: Adjunctive cenobamate was not associated with clinically significant changes in weight from baseline in patients treated for 1 and 2 years, including those receiving concomitant valproate, gabapentin, or pregabalin.

Background and Objectives: Ketogenic diet therapy (KDT) has been used as a non-pharmacological treatment for childhood refractory epilepsy. Its efficacy and safety have been described in numerous studies and reviews. However, there have been fewer studies evaluating the challenges experienced by patients and their family members when starting KDT. When implementing a new treatment method, challenges arise for both the healthcare professionals and patients, making it important to summarize the initial results and compare them with the experiences of other centers. To analyze and evaluate the efficacy and safety of KDT in children with epilepsy, as well as to consider the challenges faced by their parents/caregivers. Materials and Methods: A retrospective analysis of patients\' data (N = 30) and an analysis of the completed questionnaires of the parents/caregivers (N = 22) occurred. Results: In the study group, 66.7% of the patients had a >50% decrease in seizure frequency, and 2/3 of them had a >90% decrease in seizure frequency or were seizure-free, which enabled reducing the anti-seizure medications in 36.4% of the patients, as well as reducing the hospital visits. Cognitive improvement and better alertness were subjectively reported by 59.1% of the parents/caregivers. No dangerous long-term adverse effects of KDT have been observed in the study group. The patients with generalized epilepsy experienced significantly more adverse events. Most of the adverse effects of KDT were related to the digestive system, but usually they were temporary and controllable. The challenges of the parents/caregivers were mostly related to social life issues and financial difficulties; the medical-related challenges were minimal. Conclusions: KDT is an effective and safe treatment option for children with drug-resistant epilepsy, and the challenges faced by families are resolvable. In order to ensure effective KDT, a multidisciplinary team is required. This would ensure smooth and comprehensive care and the timely resolution of emerging problems. The cooperation of the families undergoing KDT is also important, enabling them to share their experiences.

Patients with epileptic encephalopathy with spike wave activation in sleep (EE-SWAS) often display drug-resistant epilepsy. The activation of epileptic activity during sleep is associated temporally with neurocognitive impairment and causes a spectrum of disorders within the epilepsy-aphasia syndrome. The prognosis is dependent on promptness of treatment and etiology. However, there is no clear consensus with regards to the optimal management for patients with EE-SWAS. We queried our Pediatric Epilepsy Outcome-Informatics Project (PEOIP) database for all patients treated with anakinra in our centre. We herein report a case of a female with EE-SWAS, who demonstrated remarkable neurocognitive improvement with anakinra. We suggest that a trial of anakinra may be an option for patients with EE-SWAS due to non-structural and possibly inflammatory etiology.

OBJECTIVE: To elucidate the patient\'s journey to epilepsy surgery and identify the risk factors contributing to surgical delay in pediatric patients with drug-resistant epilepsy (DRE) due to focal cortical dysplasia (FCD).
METHODS: A retrospective review was conducted of 93 pediatric patients who underwent curative epilepsy surgery for FCD between January 2012 and March 2023 at a tertiary epilepsy center. The Odyssey plot demonstrated the treatment process before epilepsy surgery, including key milestones of epilepsy onset, first hospital visit, epilepsy diagnosis, MRI diagnosis, DRE diagnosis, and surgery. The primary outcome was surgical delay; the duration from DRE to surgery. Multivariate linear regression models were used to examine the association between surgical delay and clinical, investigative, and treatment characteristics.
RESULTS: The median age at seizure onset was 1.3 years (interquartile range [IQR] 0.14-3.1), and at the time of surgery, it was 6 years (range 1-11). Notably, 46% experienced surgical delays exceeding two years. The Odyssey plot visually highlighted that surgical delay comprised a significant portion of the patient journey. Although most patients underwent MRI before referral, MRI abnormalities were identified before referral only in 39% of the prolonged group, compared to 70% of the non-prolonged group. Multivariate analyses showed that delayed notification of MRI abnormalities, longer duration from epilepsy onset to DRE, older age at onset, number of antiseizure medications tried, and moderate to severe intellectual disability were significantly associated with prolonged surgical delay.
CONCLUSIONS: Pediatric DRE patients with FCD experienced a long journey until surgery. Early and accurate identification of MRI abnormalities is important to minimize surgical delays.

Epileptic seizures recorded with stereoelectroencephalography (SEEG) can take a fraction of a second or several seconds to propagate from one region to another. What explains such propagation patterns? We combine tractography and SEEG to determine the relationship between seizure propagation and the white matter architecture and to describe seizure propagation mechanisms. Patient-specific spatiotemporal seizure propagation maps were combined with tractography from diffusion imaging of matched subjects from the Human Connectome Project. The onset of seizure activity was marked on a channel-by-channel basis by two board-certified neurologists for all channels involved in the seizure. We measured the tract connectivity (number of tracts) between regions-of-interest pairs among the seizure onset zone, regions of seizure spread, and non-involved regions. We also investigated how tract-connected the seizure onset zone is to regions of early seizure spread compared to regions of late spread. Comparisons were made after correcting for differences in distance. Sixty-nine seizures were marked across 26 patients with drug-resistant epilepsy; 11 were seizure free after surgery (Engel IA) and 15 were not (Engel IB-IV). The seizure onset zone was more tract connected to regions of seizure spread than to non-involved regions (p<0.0001); however, regions of seizure spread were not differentially tract-connected to other regions of seizure spread compared to non-involved regions. In seizure free patients only, regions of seizure spread were more tract connected to the seizure onset zone than to other regions of spread (p<0.0001). Over the temporal evolution of a seizure, the seizure onset zone was significantly more tract connected to regions of early spread compared to regions of late spread in seizure free patients only (p<0.0001). By integrating information on structure, we demonstrate that seizure propagation is likely mediated by white matter tracts. The pattern of connectivity between seizure onset zone, regions of spread and non-involved regions demonstrates that the onset zone may be largely responsible for seizures propagating throughout the brain, rather than seizures propagating to intermediate points, from which further propagation takes place. Our findings also suggest that seizure propagation over seconds may be the result of a continuous bombardment of action potentials from the seizure onset zone to regions of spread. In non-seizure free patients, the paucity of tracts from the presumed seizure onset zone to regions of spread suggests that the onset zone was missed. Fully understanding the structure-propagation relationship may eventually provide insight into selecting the correct targets for epilepsy surgery.

BACKGROUND: Drug-resistant epilepsy (DRE) remains poorly-controlled in c.33% of patients, and up to 50% of patients suffering from DRE are deemed not to be suitable candidates for resective surgery. For these patients, deep brain stimulation (DBS) may constitute the last resort in the treatment of DRE.
BACKGROUND: We undertook a systematic review of the current literature on DBS efficacy and the safety of two thalamic nuclei-anterior nucleus of the thalamus (ANT) and the centromedian nucleus of the thalamus in the management of patients with DRE. A search using two electronic databases, the Medical Literature, Analysis, and Retrieval System on-line (MEDLINE) and the Cochrane Central Register of Controlled Trials (CEN-TRAL) was conducted.
CONCLUSIONS: We found 30 articles related to ANT DBS and 13 articles related to CMN DBS which were further analysed. Based on the clinical research articles, we found a mean seizure frequency reduction for both thalamic nuclei. For ANT DBS, the mean seizure frequency reduction ranged from 48% to 75%, and for CMN DBS from 46.7% to 91%. The responder rate (defined as at least 50% reduction in seizure frequency) was reported to be 53.2-75% for patients after ANT DBS and 50-90% for patients after CMN DBS.
CONCLUSIONS: ANT and CMN DBS appear to be safe and efficacious treatments, particularly in patients with refractory partial seizures and primary generalised seizures. ANT DBS reduces most effectively seizures originating in the temporal and frontal lobes. CMN DBS reduces mostly primary generalised tonic-clonic and atypical absences and atonic seizures. Seizures related to Lennox-Gastaut syndrome respond very favourably to CMN DBS.