Purpose: These consensus guidelines by the American Clinical Neurophysiology Society (ACNS) describe best practices for performing intraoperative Electrocorticography (ioECoG) using subdural or depth electrodes for adult and pediatric population. Methods: A group of ACNS members was convened to develop technical standards for performing ioECoG. PubMed searches were performed to identify pertinent peer-reviewed literature. Sections were assigned to individual authors based on expertise. Consensus was achieved during subsequent group discussions to develop evidence-based recommendations to the extent possible. Recommendations: Communication between the neurosurgical and the neurophysiology teams is essential in verifying and documenting the location of the contacts. Most authors recommend ioECoG recordings of at least 5 and up to 30 minutes in duration to allow for sufficient observation of interictal activity. The anesthesia should be adjusted to allow continuous EEG activity and to minimize the effect on the ioECoG recording during general anesthesia or awake surgery. The surgical procedure and technical report should separate ioECoG recordings to define the irritative zone from ioECoG findings during functional mapping. The neurophysiology physician’s physical presence in the operating room is required in the definition of the services. Conclusion: These consensus guidelines by the ACNS describe best practices for performing intraoperative ECoG based on published literature and expert consensus.
Surgical Treatment of Brain Tumor-Related Epilepsy: Current and Emerging Strategies
Brain tumor-related epilepsy (BTRE) is a common and debilitating symptom of central nervous system (CNS) tumors. The epileptogenic zone, defined as cortex responsible for seizure generation, is located at the peritumoral region for most tumors, and lower-grade intrinsic brain tumors have the highest seizure incidence. Surgery is often the most effective treatment for the reduction in seizures in BTRE. However, surgical decisions have historically often been made exclusively for oncologic reasons, with less emphasis on seizure control. Surgical approaches for all tumor types are reviewed, highlighting relevant risk factors. Adjunctive tools during surgery, such as intraoperative electrocorticography (ECoG), may help identify and remove surrounding brain areas which are epileptogenic. Minimally invasive surgery is also gaining traction, given its utility in treating seizures deep-seated tumors. This review explores epileptogenic brain tumors, surgery for BTRE, and emerging strategies to better achieve seizure control.
American Clinical Neurophysiology Society Technical Standards for Electrical Stimulation With Intracranial Electrodes for Functional Brain Mapping and Seizure Induction
Purpose: These American Clinical Neurophysiology Society technical standards suggest best practices for electrical stimulation mapping (ESM) with subdural and stereotactic depth electrodes for seizure induction and mapping of brain function. Methods: A working group was convened from American Clinical Neurophysiology Society membership with expertise in ESM. PubMed searches were performed to identify pertinent peer-reviewed literature. Recurrent meetings reviewed progress, built consensus by discussion, and developed evidence-based recommendations to the extent possible. Recommendations: Stimulators used for ESM should have sufficient dynamic range, ability to interrupt a stimulus train, and ictal disrupt mechanism(s). Charge density should be calculated for the specific electrodes and ESM settings, the maximum safe limits being 52 to 57 μC/cm 2 /phase for subdural electrodes and not established for stereotactic depth electrodes. Subdural ESM for functional mapping is typically performed at 50-Hz pulse frequency, 200- to 300-µs pulse width, 2- to 8-s train duration, and 1- to 20-mA current strength. Stereo ESM is commonly performed using 2 different pulse frequencies: 1 Hz (300–500 µs pulse width, train duration up to 30 s, and often a constant current of 3–5 mA), and 50 Hz (100–500 µs pulse width, train duration 2-8 s, and 0.5–10 mA current intensity). Conclusions: This guideline provides technical standards for the performance of ESM, which will likely evolve over time with advances in technology and additional evidence (also see Graphical Abstract).
Discontinuation of Antiseizure Medications in Patients With Brain Tumors
Abstract Tumor-related epilepsy (TRE) is a frequent and major consequence of brain tumors. Management of TRE is required throughout the course of disease and a deep understanding of diagnosis and treatment is key to improving quality of life. Gross total resection is favored from both an oncologic and epilepsy perspective. Shared mechanisms of tumor growth and epilepsy exist, and emerging data will provide better targeted therapy options. Initial treatment with antiseizure medications (ASM) in conjunction with surgery and/or chemoradiotherapy is typical. The first choice of ASM is critical to optimize seizure control and tolerability considering the effects of the tumor itself. These agents carry a potential for drug–drug interactions and therefore knowledge of mechanisms of action and interactions is needed. A review of adverse effects is necessary to guide ASM adjustments and decision-making. This review highlights the essential aspects of diagnosis and treatment of TRE with ASMs, surgery, chemotherapy, and radiotherapy while indicating areas of uncertainty. Future studies should consider the use of a standardized method of seizure tracking and incorporating seizure outcomes as a primary endpoint of tumor treatment trials.
Highlights From the Annual Meeting of the American Epilepsy Society 2022
With more than 6000 attendees between in-person and virtual offerings, the American Epilepsy Society Meeting 2022 in Nashville, felt as busy as in prepandemic times. An ever-growing number of physicians, scientists, and allied health professionals gathered to learn a variety of topics about epilepsy. The program was carefully tailored to meet the needs of professionals with different interests and career stages. This article summarizes the different symposia presented at the meeting. Basic science lectures addressed the primary elements of seizure generation and pathophysiology of epilepsy in different disease states. Scientists congregated to learn about anti-seizure medications, mechanisms of action, and new tools to treat epilepsy including surgery and neurostimulation. Some symposia were also dedicated to discuss epilepsy comorbidities and practical issues regarding epilepsy care. An increasing number of patient advocates discussing their stories were intertwined within scientific activities. Many smaller group sessions targeted more specific topics to encourage member participation, including Special Interest Groups, Investigator, and Skills Workshops. Special lectures included the renown Hoyer and Lombroso, an ILAE/IBE joint session, a spotlight on the impact of Dobbs v. Jackson on reproductive health in epilepsy, and a joint session with the NAEC on coding and reimbursement policies. The hot topics symposium was focused on traumatic brain injury and post-traumatic epilepsy. A balanced collaboration with the industry allowed presentations of the latest pharmaceutical and engineering advances in satellite symposia.
True abdominal epilepsy is clonic jerking of the abdominal musculature*
AbstractAims Abdominal epilepsy (AE) has long been reported as a rare phenomenon in children with various episodic gastrointestinal sensory and painful symptoms suspected to be due to epileptic seizures. Originally, AE was diagnosed when abdominal sensory or painful symptoms were associated with pain, temporal lobe origin, an epileptiform or paroxysmal EEG pattern, and a clinical response to antiseizure medication. AE has also been associated with non‐epileptic etiologies such as migraine. Reports of abdominal epilepsy based on an abnormal EEG or clinical response to antiseizure medication without diagnosis confirmation by video‐EEG are at best speculative, and at worst, misdiagnoses.Methods We describe three adult patients with focal aware motor seizures manifesting as recurrent, isolated prolonged painless rhythmic clonic jerking of the abdominal musculature including epilepsia partialis continua.Results All patients had a contralateral structural lesion on high‐resolution brain MRI in the abdominal region of the motor homunculus. Standard EEG was unrevealing and only after extra EEG electrodes and video‐EEG monitoring was the ictal origin confirmed.Conclusions Historically, AE has been described as a disorder involving subjective sensory symptoms including vague abdominal pain, instead of epileptic motor signs of abdominal clonic jerking. We recommend replacing the use of vague terms such as AE with International League Against Epilepsy terminology along with diagnostic confirmation validated by video‐EEG monitoring. [Published with video sequence].