Back to Basics: Care of the Stereotactic EEG Implanted Patient.

PURPOSE: Stereotactic EEG (SEEG) is gaining increasing popularity in the United States. Patients undergoing SEEG have unique challenges, and their needs are different compared with noninvasive cases. We aim to describe the medical, nursing, and other institutional practices of SEEG evaluations among tertiary referral (level IV) epilepsy centers accredited by the National Association of Epilepsy Centers. METHODS: We analyzed data obtained from a Research Electronic Data Capture (REDCap) survey we formulated and distributed to directors of all level IV epilepsy centers listed by the National Association of Epilepsy Center. Most questions were addressed to the adult and pediatric SEEG programs separately. RESULTS: Among 199 epilepsy center directors invited to complete the survey, 90 (45%) responded. Eighty-three centers (92%) reported they perform SEEG evaluations. Of the 83 respondents, 56 perform SEEG in adult and 47 in pediatric patients. Twenty-two centers evaluate both pediatric and adult subjects. The highest concordance of SEEG workflow was in (1) epilepsy monitoring unit stay duration (1-2 weeks, 79% adult and 85% pediatric programs), (2) use of sleep deprivation (94% both adult and pediatric) and photic stimulation (79% adult and 70% pediatric) for seizure activation, (3) performing electrical cortical stimulation at the end of SEEG evaluation after spontaneous seizures are captured (84% adult and 88% pediatric), and (4) daily head-wrap inspection (76% adult and 80% pediatric). Significant intercenter variabilities were noted in the other aspects of SEEG workflow. CONCLUSIONS: Results showed significant variability in SEEG workflow across polled centers. Prospective, multicenter protocols will help the future development and harmonization of optimal practice patterns.

Responsive neurostimulation as a treatment for super-refractory focal status epilepticus: a systematic review and case series.

OBJECTIVE: Super-refractory status epilepticus (SRSE) has high rates of morbidity and mortality. Few published studies have investigated neurostimulation treatment options in the setting of SRSE. This systematic literature review and series of 10 cases investigated the safety and efficacy of implanting and activating the responsive neurostimulation (RNS) system acutely during SRSE and discusses the rationale for lead placement and selection of stimulation parameters. METHODS: Through a literature search (of databases and American Epilepsy Society abstracts that were last searched on March 1, 2023) and direct contact with the manufacturer of the RNS system, 10 total cases were identified that utilized RNS acutely during SE (9 SRSE cases and 1 case of refractory SE [RSE]). Nine centers obtained IRB approval for retrospective chart review and completed data collection forms. A tenth case had published data from a case report that were referenced in this study. Data from the collection forms and the published case report were compiled in Excel. RESULTS: All 10 cases presented with focal SE: 9 with SRSE and 1 with RSE. Etiology varied from known lesion (focal cortical dysplasia in 7 cases and recurrent meningioma in 1) to unknown (2 cases, with 1 presenting with new-onset refractory focal SE [NORSE]). Seven of 10 cases exited SRSE after RNS placement and activation, with a time frame ranging from 1 to 27 days. Two patients died of complications due to ongoing SRSE. Another patient's SE never resolved but was subclinical. One of 10 cases had a device-related significant adverse event (trace hemorrhage), which did not require intervention. There was 1 reported recurrence of SE after discharge among the cases in which SRSE resolved up to the defined endpoint. CONCLUSIONS: This case series offers preliminary evidence that RNS is a safe and potentially effective treatment option for SRSE in patients with 1-2 well-defined seizure-onset zone(s) who meet the eligibility criteria for RNS. The unique features of RNS offer multiple benefits in the SRSE setting, including real-time electrocorticography to supplement scalp EEG for monitoring SRSE progress and response to treatment, as well as numerous stimulation options. Further research is indicated to investigate the optimal stimulation settings in this unique clinical scenario.

Postoperative seizures following endoscopic third ventriculostomy and choroid plexus cauterization: a case series.

OBJECTIVE: In this study, the authors sought to investigate variables associated with postoperative seizures following endoscopic third ventriculostomy and choroid plexus cauterization (ETV/CPC) for treatment of pediatric hydrocephalus. METHODS: A retrospective analysis of 37 patients who underwent ETV/CPC for treatment of hydrocephalus at an academic medical center from September 2016 to March 2021 was conducted. Demographics, etiology of hydrocephalus, operative details, electroencephalography (EEG) data, MRI findings, need for subsequent procedures, perioperative laboratory tests, medical history, and presence of clinical postoperative seizures were collected. Postoperative seizures were defined as clinical seizures within 24 hours of surgery. Eighteen patients received levetiracetam intraoperatively as well as over the next 7 days postoperatively for seizure prophylaxis. RESULTS: Of 37 included patients, 9 (24%) developed clinical seizures within 24 hours after surgery, 5 of whom subsequently had electroclinical seizures captured on video-EEG. The clinical seizures in 4 of those 5 patients (80%) may have been associated with the hemisphere of the brain through which the endoscope was introduced. The median corrected age of the cohort was 3.4 months. The median corrected age of patients who did not develop postoperative seizures was 2.3 months compared with 0.7 months for patients who did develop postoperative seizures (p > 0.99). Postoperative seizures occurred in 43% (3/7) of prenatally repaired myelomeningocele patients versus 29% (2/7) of postnatally repaired myelomeningocele patients. Of the 18 patients who received prophylactic levetiracetam, none (0%) developed postoperative seizures compared with 9 of the 19 patients (47%) who did not receive prophylactic levetiracetam (p = 0.014). CONCLUSIONS: Postoperative seizures were recorded in 24% of the pediatric patients who underwent ETV/CPC for hydrocephalus, which is higher than previously reported rates in the literature of 5%. Since 80% of the postoperative electrographic seizures may have been associated with the hemisphere through which the endoscope was introduced, the surgical entry site may contribute to postoperative seizure development. In patients who received prophylactic perioperative levetiracetam, the postoperative seizure incidence dropped to 0% compared with 47% in those who did not receive prophylactic perioperative levetiracetam. This finding indicates that the use of prophylactic perioperative levetiracetam may be efficacious in the prevention of clinical seizures in this patient population.

Feasibility of stereo electroencephalogram (SEEG) with little to no scalp bone; a case report.

Stereo electroencephalogram (SEEG) electrode placement with cranially fixed guide bolts is recognized as one of the most accurate and safest implantation strategies to sample deep and buried cortex during certain clinical scenarios involving epilepsy surgery. Bone thickness of less than 2 mm is a relative contraindication to SEEG. Here, we describe a case drug-resistant focal epilepsy where prior craniotomies, infections and radiation therapy yielded limited skull bone requiring invasive EEG monitoring. Due to the inability to use bolts over areas with limited skull bone, we successfully utilized a combination of the standard and a modified SEEG techniques for implantation and stabilization of intracranial electrodes without complications. This strategy enabled optimal intracranial EEG monitoring and surgical management of the patient's drug-resistant focal seizures.

Brain-responsive neurostimulation treatment in patients with GAD65 antibody-associated autoimmune mesial temporal lobe epilepsy.

Glutamic acid decarboxylase 65-kilodalton isoform (GAD65) antibodies have been associated with multiple nonneurological and neurological syndromes including autoimmune epilepsy (AE). Although immunotherapy remains the cornerstone for the treatment of AE, those with GAD65 Ab-associated AE (GAD65-AE) remain refractory to immunotherapy and antiseizure medication (ASM). Outcomes of epilepsy surgery in this patient population have also been unsatisfactory. The role of neuromodulation therapy, particularly direct brain-responsive neurostimulation therapy, has not been previously examined in GAD65-AE. Here, we describe four consecutive patients with refractory GAD-65-associated temporal lobe epilepsy (GAD65-TLE) receiving bilateral hippocampal RNS System treatment. The RNS System treatment was well tolerated and effective in this study cohort. Three patients had a >50% clinical seizure reduction, and one patient became clinically seizure-free following resective surgery informed by the RNS System data with continued RNS System treatment. In all four of our patients, the long-term ambulatory data provided by the RNS System allowed us to gain objective insights on electrographic seizure lateralization, patterns, and burden as well as guided immunotherapy and ASM optimization. Our results suggest the potential utility of the RNS System in the management of ASM intractable GAD65-AE.

Electroencephalography and Brain MRI Patterns in Encephalopathy.

INTRODUCTION: Using electroencephalography (EEG) and histology in patients with diffuse encephalopathy, Gloor et al reported that paroxysmal synchronous discharges (PSDs) on EEG required combined cortical gray (CG) and "subcortical" gray (SCG) matter pathology, while polymorphic delta activity (PDA) occurred in patients with white matter pathology. In patients with encephalopathy, we compared EEG findings and magnetic resonance imaging (MRI) to determine if MRI reflected similar pathological EEG correlations. METHODS: Retrospective case control study of 52 cases with EEG evidence of encephalopathy and 50 controls without evidence of encephalopathy. Review of clinical, EEG and MRI data acquired within 4 days of each other. RESULTS: The most common EEG finding in encephalopathy was background slowing, in 96.1%. We found PSDs in 0% of cases with the combination of CG and SCG abnormalities. Although 13.5% (n=7) had PSDs on EEG; 3 of these had CG and 4 had SCG abnormalities. A total of 73.1% (38/52) had white matter abnormalities-of these 28.9% (11/38) had PDA. CONCLUSION: PSDs were found with either CG or "SCG" MRI abnormalities and did not require a combination of the two. In agreement with Gloor et al, PDA occurred with white matter MRI abnormalities in the absence of gray matter abnormalities.

Stigma and quality of life at long-term follow-up after surgery for epilepsy in Uganda.

Epilepsy is a worldwide health problem with a 10-fold greater prevalence in the developing world. Commonly, the seizure focus is in the temporal lobe, and seizures in about 30% of people with epilepsy are intractable to medication. For these individuals, surgery for intractable temporal lobe epilepsy (iTLE) is more effective than medication alone and may be the only option for cure. Intractable temporal lobe epilepsy is associated with elevated morbidity and mortality, reduced quality of life (QOL), and associated stigma particularly occurring in the developing world. Individuals with intractable epilepsy who participated in an earlier Uganda pilot study were selected for the current study based on their undergoing previous surgery for iTLE or having comparable seizure type who did not have surgery. At long-term follow-up, 10 who underwent surgery for iTLE in addition to 9 patients with focal dyscognitive type epilepsy who did not have surgery were evaluated in the current study. Tests were administered to look at various outcome parameters: seizure severity, QOL, stigma, and self-esteem. Stigma and self-esteem were additionally evaluated in the parent/caregiver. Seventy-percent of surgical resection patients were seizure-free at 8 years postsurgery. The QOLIE-31 scores were higher in surgical patients. Child/patient and parent/proxy surveys identified lower stigma in seizure-free patients. The results suggest that surgery for iTLE is an effective treatment for epilepsy in the developing world and provides an opportunity to reduce stigma and improve QOL.

Electroencephalographic and fluorodeoxyglucose-positron emission tomography correlates in anti-N-methyl-d-aspartate receptor autoimmune encephalitis.

IMPORTANCE: Anti-N-methyl-d-aspartate receptor (anti-NMDAR) autoimmune encephalitis is an increasingly recognized cause of limbic encephalitis (LE). Prolonged LE and limbic status epilepticus (LSE) share many features. The ability to distinguish between the two is crucial in directing appropriate therapy because of the potential iatrogenesis associated with immunosuppression and anesthetic-induced coma. OBSERVATIONS: A 34-year-old woman with recurrent LE developed behavioral changes, global aphasia, and repetitive focal and generalized tonic-clonic seizures. Because asymmetric rhythmic delta patterns recurred on electroencephalography (EEG) despite treatment with nonsedating antiepileptic drugs followed by anesthetic-induced coma, an investigation to distinguish LSE from LE was undertaken. Implanted limbic/temporal lobe depth electrodes revealed no epileptiform activity. Brain single-photon emission computerized tomography (SPECT) showed no hyperperfusion, and brain fluorodeoxyglucose-positron emission tomography (FDG-PET) showed hypermetabolism in the left frontal, temporal, and parietal cortices. Anti-N-methyl-d-aspartate receptor autoimmune encephalitis was diagnosed based detection of anti-NMDAR antibody in the cerebrospinal fluid (CSF). With chronic immunosuppression, the resolution of brain FDG-PET abnormalities paralleled clinical improvement. CONCLUSIONS AND RELEVANCE: This case of anti-NMDAR autoimmune encephalitis illustrates the challenges of distinguishing prolonged LE from LSE. We discuss the parallels between these two conditions and propose a management paradigm to optimize evaluation and treatment.

Surgery for pharmacoresistant epilepsy in the developing world: A pilot study.

Epilepsy prevalence in the developing world is many fold that found in developed countries. For individuals whose conditions failed to respond to pharmacotherapy, surgery is the only opportunity for cure. In Uganda, we developed a center for treatment of intractable temporal lobe epilepsy (iTLE) that functions within the technologic and expertise constraints of a severely low resource area. Our model relies on partnership with epilepsy professionals and training of local staff. Patients were prescreened at regional clinics for iTLE. Individuals meeting inclusion criteria were referred to the treating Ugandan hospital (CURE Children's' Hospital of Uganda, CCHU) for video-EEG (electroencephalography), computed tomography (CT) imaging, and neuropsychological evaluation. Data were transferred to epilepsy experts for analysis and treatment recommendations. Ten patients were diagnosed with iTLE and surgically treated at CCHU. Six (60%) were seizure free, and there was no neurologic morbidity or mortality. Our model for surgical treatment of pharmacoresistant TLE has functioned successfully in a true developing world low resource setting.