Association of reductions in rescue medication requirements with vagus nerve stimulation: Results of long-term community collected data from a seizure diary app.

OBJECTIVE: To assess the impact of vagus nerve stimulation (VNS) on quality of life contributors such as rescue medications. METHODS: Using the seizure diary application SeizureTracker™ database, we examined trends in rescue administration frequency before and after the first recorded VNS magnet swipe in patients with drug-resistant epilepsy who had 1) At least one VNS magnet swipe recorded in the diary, and 2) Recorded usage of a benzodiazepine rescue medication (RM) within 90 days prior to the first swipe. A paired Wilcoxon rank-sum test was used to assess changes in RM usage frequency between 30-, 60-, 90-, 180- and 360-day intervals beginning 30 days after first magnet swipe. Longitudinal changes in RM usage frequency were assessed with a generalized estimating equation model. RESULTS: We analyzed data of 95 patients who met the inclusion criteria. Median baseline seizure frequency was 8.3 seizures per month, with median baseline rescue medication usage frequency of 2.1 administrations per month (SD 3.3). Significant reductions in rescue medication usage were observed in the 91 to 180 day interval after first VNS magnet swipe, and at 181 to 360 days and at 361 to 720 days, with the magnitude of reduction increasing over time. Decreases in rescue medication usage were sustained when controlling for patients who did not record rescue medication use after the first VNS magnet swipe (N=91). Significant predictors of reductions in rescue medication included baseline frequency of rescue medication usage and time after first VNS magnet swipe. SIGNIFICANCE: This retrospective analysis suggests that usage of rescue medications is reduced following the start of VNS treatment in patients with epilepsy, and that the magnitude of reduction may progressively increase over time.

Feasibility and safety of stereoelectroencephalography in young children.

PURPOSE: Stereoelectroencephalography (SEEG) is a diagnostic surgery that implants electrodes to identify areas of epileptic onset in patients with drug-resistant epilepsy (DRE). SEEG is effective in identifying the epileptic zone; however, placement of electrodes in very young children has been considered contraindicated due to skull thinness. The goal of this study was to evaluate if SEEG is safe and accurate in young children with thin skulls. METHODS: Four children under the age of two years old with DRE underwent SEEG to locate the region of seizure onset. Presurgical planning and placement of electrodes were performed using ROSA One Brain. Preoperative electrode plans were merged with postoperative CT scans to determine accuracy. Euclidean distance between the planned and actual trajectories was calculated using a 3D coordinate system at both the entry and target points for each electrode. RESULTS: Sixty-three electrodes were placed among four patients. Mean skull thickness at electrode entry sites was 2.34 mm. The mean difference between the planned and actual entry points was 1.12 mm, and the mean difference between the planned and actual target points was 1.73 mm. No significant correlation was observed between planned and actual target points and skull thickness (Pearson R = - 0.170). No perioperative or postoperative complications were observed. CONCLUSIONS: This study demonstrates that SEEG can be safe and accurate in children under two years of age despite thin skulls. SEEG should be considered for young children with DRE, and age and skull thickness are not definite contraindications to the surgery.

Responsive neurostimulation of the frontal lobe for the detection and treatment of seizures in intractable epilepsy due to tuberous sclerosis complex: illustrative case.

BACKGROUND: Responsive neurostimulation (RNS) is often considered to be a palliative therapy for drug-resistant epilepsy (DRE) and is generally not considered to be a treatment for patients with tuberous sclerosis complex (TSC). Here, the authors present the case of a 24-year-old male with TSC who obtained seizure freedom following RNS device implantation. OBSERVATIONS: Prior to RNS device implantation, the patient underwent tuberectomies, subependymal giant cell astrocytoma resection, vagus nerve stimulator placement, and left frontal lobe resection but continued to have frequent seizures. An RNS device was implanted, which initially led to a decrease in seizures, but he continued to have 12 seizures per month. He then underwent lead revision for stimulation via a different electrode. After that lead change, he had no seizures for almost 3 years. In the following 3 years, he had two episodes of breakthrough seizures, both of which occurred with medication weans. Although the patient still requires antiseizure medication, he has had years of seizure freedom with RNS therapy. LESSONS: This study exhibits the potential effectiveness of RNS therapy for patients with TSC and DRE. RNS should be considered for patients with TSC when other therapies have not sufficiently treated their epilepsy. https://thejns.org/doi/10.3171/CASE23411.

Central Nervous System Infections in Patients With Ventriculoperitoneal Shunts Admitted for Primary Abdominal Infections: A US Nationwide Cohort Analysis.

BACKGROUND AND OBJECTIVES: Although ventriculoperitoneal (VP) shunts are a common treatment for hydrocephalus, there are complication risks including infections. Late complications such as ventriculitis from ascending abdominal infections can have severe consequences. However, the incidence of central nervous system (CNS) infections in VP shunt patients with abdominal infections is not well understood. We aimed to determine the incidence of CNS infections in VP shunt patients admitted with abdominal infections. METHODS: Using the National Inpatient Sample, we studied patients from 2016 to 2019 to determine the incidence of CNS infections in VP shunt patients admitted with abdominal infections. Results were compared with VP shunt patients admitted for primary pneumonia. RESULTS: Among 725 VP shunt patients presenting with abdominal infections, 20 (2.8%) had CNS infections. Chronic obstructive pulmonary disease, hypertension, older age, and a smoking history were more common in patients with CNS infections and primary abdominal infection (P < .05). Patients who developed CNS infection had a significantly higher likelihood of both blood transfusion and coma but a lower likelihood of seizures. VP shunt patients with CNS infections were more likely to undergo shunt removal (odds ratio [OR] = 23.167, P < .001). 4.1% of VP shunt patients with primary abdominal infections died during admission. In a population of primary abdominal infection and pneumonia patients with VP shunts, a multivariate logistic regression analysis controlling for age, sex, and comorbidities identified abdominal infection as an independent risk factor for both CNS infection (OR = 51.208, P < .001) and inpatient death (OR = 3.417, P < .001). Among 6620 VP shunt patients admitted with primary pneumonia, only 5 (0.1%) had CNS infection compared with 20 (2.8%) in those with a primary abdominal infection (OR = 37.532, P < .001), and mortality was 1.6% vs 4.1% for those with a primary abdominal infection (P < .05). CONCLUSION: CNS infections in VP-shunted patients with abdominal infections are relatively rare but may lead to increased risks of death and other serious adverse outcomes.

Overcoming Graft Rejection in Induced Pluripotent Stem Cell-Derived Inhibitory Interneurons for Drug-Resistant Epilepsy.

BACKGROUND: Cell-based therapies for drug-resistant epilepsy using induced pluripotent stem cell-derived inhibitory interneurons are now in early-phase clinical trials, building on findings from trials in Parkinson's disease (PD) and Huntington's disease (HD). Graft rejection and the need for immunosuppressive therapy post-transplantation pose potential barriers to more epilepsy patients becoming potential candidates for inhibitory interneurons transplantation surgery. OBJECTIVES: The present literature review weighs the evidence for and against human leukocyte antigen (HLA)-mediated graft rejection in PD and HD and examines the potential advantages and drawbacks to five broad approaches to cell-based therapies, including autologous cell culture and transplantation, in vivo reprogramming of glial cells using viral vectors, allogeneic transplantation using off-the-shelf cell lines, transplantation using inhibitory interneurons cultured from HLA-matched cell lines, and the use of hypoimmunogenic-induced pluripotent stem cell-derived inhibitory interneurons. The impact of surgical technique and associated needle trauma on graft rejection is also discussed. METHODS: Non-systematic literature review. RESULTS: While cell-based therapies have enjoyed early successes in treating a host of central nervous system disorders, the immunologic reaction against surgical procedures and implanted materials has remained a major obstacle. CONCLUSIONS: Adapting cell-based therapies using iPSC-derived inhibitory interneurons for epilepsy surgery will similarly require surmounting the challenge of immunogenicity.

Myasthenia gravis in a pediatric patient with Lennox-Gastaut syndrome following responsive neurostimulation device implantation: illustrative case.

BACKGROUND: Myasthenia gravis (MG) is an autoimmune disorder in which the postsynaptic acetylcholine receptor of the neuromuscular junction is destroyed by autoantibodies. The authors report a case of MG in a pediatric patient who also suffered from Lennox-Gastaut syndrome (LGS) and is one of a limited number of pediatric patients who have undergone placement of a responsive neurostimulation (RNS) device (NeuroPace). OBSERVATIONS: A 17-year-old female underwent placement of an RNS device for drug-resistant epilepsy in the setting of LGS. Five months after device placement, the patient began experiencing intermittent slurred speech, fatigue, and muscle weakness. Initially, the symptoms were attributed to increased seizure activity and/or medication side effects. However, despite changing medications and RNS settings, no improvements occurred. Her antiacetylcholine receptor antibodies measured 62.50 nmol/L, consistent with a diagnosis of MG. The patient was then prescribed pyridostigmine and underwent a thymectomy, which alleviated most of her symptoms. LESSONS: The authors share the cautionary tale of a case of MG in a pediatric patient who was treated with RNS for intractable epilepsy associated with LGS. Although slurred speech, fatigue, muscle weakness, and other symptoms might stem from increased seizure activity and/or medication side effects, they could also be due to MG development.

Safety of vagus nerve stimulation and responsive neurostimulation used in combination for multifocal and generalized onset epilepsy in pediatric patients.

OBJECTIVE: The aim of this study was to assess the safety and efficacy of combined active responsive neurostimulation (RNS) and vagus nerve stimulation (VNS) therapies in pediatric patients with drug-resistant epilepsy. METHODS: A single-center retrospective chart review was conducted on pediatric patients implanted with the RNS System with a concomitant active VNS System (VNS+RNS) between 2015 and 2021. Patients with at least 1 month of overlapping concomitant VNS and RNS treatment were included. Patients who had an RNS device implanted after 21 years of age, those who had responsive neurostimulators implanted after their VNS was inactivated, or those in whom the VNS battery died and was not replaced before RNS System implantation were excluded. RESULTS: Seven pediatric VNS+RNS patients were identified, and their courses of treatment were evaluated. All patients tolerated concurrent VNS and RNS treatment well, no device-device interactions were identified, and no major treatment-related adverse effects were noted. The median follow-up after RNS System implantation was 1.2 years. By electroclinical criteria, all 7 patients achieved 75%-99% reductions in the frequency of disabling seizures after RNS System implantation. By patient and caregiver report, 2 patients (28.6%) had 75%-99% reductions in the frequency of their disabling seizures, 2 patients (28.6%) achieved 50%-74% reductions, 2 patients achieved 1%-24% reduction in frequency of disabling seizures, and 1 patient (14.3%) experienced a 1%-24% increase in seizure frequency. The available VNS magnet swipe data identified 2 patients with 75%-99% reductions in seizure frequency as measured by magnet swipes, one with 25%-49% reductions and the other with 1%-24% increases in seizure frequency as measured by magnet swipes. CONCLUSIONS: This study demonstrated that RNS and VNS therapies can safely be used simultaneously in pediatric patients. RNS may potentially augment the therapeutic effects of VNS treatment. Patients in whom a response to VNS has been suboptimal should still be considered for RNS therapy.

Human cortical interneurons optimized for grafting specifically integrate, abort seizures, and display prolonged efficacy without over-inhibition.

Previously, we demonstrated the efficacy of human pluripotent stem cell (hPSC)-derived GABAergic cortical interneuron (cIN) grafts in ameliorating seizures. However, a safe and reliable clinical translation requires a mechanistic understanding of graft function, as well as the assurance of long-term efficacy and safety. By employing hPSC-derived chemically matured migratory cINs in two models of epilepsy, we demonstrate lasting efficacy in treating seizures and comorbid deficits, as well as safety without uncontrolled growth. Host inhibition does not increase with increasing grafted cIN densities, assuring their safety without the risk of over-inhibition. Furthermore, their closed-loop optogenetic activation aborted seizure activity, revealing mechanisms of graft-mediated seizure control and allowing graft modulation for optimal translation. Monosynaptic tracing shows their extensive and specific synaptic connections with host neurons, resembling developmental connection specificity. These results offer confidence in stem cell-based therapy for epilepsy as a safe and reliable treatment for patients suffering from intractable epilepsy.

Responsive Neurostimulation Targeting the Anterior, Centromedian and Pulvinar Thalamic Nuclei and the Detection of Electrographic Seizures in Pediatric and Young Adult Patients.

Background: Responsive neurostimulation (RNS System) has been utilized as a treatment for intractable epilepsy. The RNS System delivers stimulation in response to detected abnormal activity, via leads covering the seizure foci, in response to detections of predefined epileptiform activity with the goal of decreasing seizure frequency and severity. While thalamic leads are often implanted in combination with cortical strip leads, implantation and stimulation with bilateral thalamic leads alone is less common, and the ability to detect electrographic seizures using RNS System thalamic leads is uncertain. Objective: The present study retrospectively evaluated fourteen patients with RNS System depth leads implanted in the thalamus, with or without concomitant implantation of cortical strip leads, to determine the ability to detect electrographic seizures in the thalamus. Detailed patient presentations and lead trajectories were reviewed alongside electroencephalographic (ECoG) analyses. Results: Anterior nucleus thalamic (ANT) leads, whether bilateral or unilateral and combined with a cortical strip lead, successfully detected and terminated epileptiform activity, as demonstrated by Cases 2 and 3. Similarly, bilateral centromedian thalamic (CMT) leads or a combination of one centromedian thalamic alongside a cortical strip lead also demonstrated the ability to detect electrographic seizures as seen in Cases 6 and 9. Bilateral pulvinar leads likewise produced reliable seizure detection in Patient 14. Detections of electrographic seizures in thalamic nuclei did not appear to be affected by whether the patient was pediatric or adult at the time of RNS System implantation. Sole thalamic leads paralleled the combination of thalamic and cortical strip leads in terms of preventing the propagation of electrographic seizures. Conclusion: Thalamic nuclei present a promising target for detection and stimulation via the RNS System for seizures with multifocal or generalized onsets. These areas provide a modifiable, reversible therapeutic option for patients who are not candidates for surgical resection or ablation.

Activated microglia cause metabolic disruptions in developmental cortical interneurons that persist in interneurons from individuals with schizophrenia.

The mechanisms by which prenatal immune activation increase the risk for neuropsychiatric disorders are unclear. Here, we generated developmental cortical interneurons (cINs)-which are known to be affected in schizophrenia (SCZ) when matured-from induced pluripotent stem cells (iPSCs) derived from healthy controls (HCs) and individuals with SCZ and co-cultured them with or without activated microglia. Co-culture with activated microglia disturbed metabolic pathways, as indicated by unbiased transcriptome analyses, and impaired mitochondrial function, arborization, synapse formation and synaptic GABA release. Deficits in mitochondrial function and arborization were reversed by alpha lipoic acid and acetyl-L-carnitine treatments, which boost mitochondrial function. Notably, activated-microglia-conditioned medium altered metabolism in cINs and iPSCs from HCs but not in iPSCs from individuals with SCZ or in glutamatergic neurons. After removal of activated-microglia-conditioned medium, SCZ cINs but not HC cINs showed prolonged metabolic deficits, which suggests that there is an interaction between SCZ genetic backgrounds and environmental risk factors.