Dual Treatment of Refractory Focal Epilepsy and Obsessive-Compulsive Disorder With Intracranial Responsive Neurostimulation.

Purpose of the Review: Intracranial neurostimulation is a well-established treatment of neurologic conditions such as drug-resistant epilepsy (DRE) and movement disorders, and there is emerging evidence for using deep brain stimulation to treat obsessive-compulsive disorder (OCD) and depression. Nearly all published reports of intracranial neurostimulation have focused on implanting a single device to treat a single condition. The purpose of this review was to educate neurology clinicians on the background literature informing dual treatment of 2 comorbid neuropsychiatric conditions epilepsy and OCD, discuss ethical and logistical challenges to dual neuropsychiatric treatment with a single device, and demonstrate the promise and pitfalls of this approach through discussion of the first-in-human closed-looped responsive neurostimulator (RNS) implanted to treat both DRE (on-label) and OCD (off-label). Recent Findings: We report the first implantation of an intracranial closed-loop neurostimulation device (the RNS system) with the primary goal of treating DRE and a secondary exploratory goal of managing treatment-refractory OCD. The RNS system detects electrophysiologic activity and delivers electrical stimulation through 1 or 2 electrodes implanted into a patient's seizure-onset zones (SOZs). In this case report, we describe a patient with treatment-refractory epilepsy and OCD where the first lead was implanted in the right superior temporal gyrus to target the most active SOZ based on stereotactic EEG (sEEG) recordings and semiology. The second lead was implanted to target the right anterior peri-insular region (a secondary SOZ on sEEG) with the distal-most contacts in the right nucleus accumbens, a putative target for OCD neurostimulation treatment. The RNS system was programmed to detect and record the unique electrophysiologic signature of both the patient's seizures and compulsions and then deliver tailored electrical pulses to disrupt the pathologic circuitry. Summary: Dual treatment of refractory focal epilepsy and OCD with an intracranial closed-loop neurostimulation device is feasible, safe, and potentially effective. However, there are logistical challenges and ethical considerations to this novel approach to treatment, which require complex care coordination by a large multidisciplinary team.

Responsive neurostimulation as a therapy for epilepsy following new-onset refractory status epilepticus: Case series and review of the literature.

OBJECTIVE: To report clinical outcomes of patients who presented with new-onset refractory status epilepticus (NORSE), developed drug-resistant epilepsy (DRE), and were treated with responsive neurostimulation (RNS). METHODS: We performed a retrospective review of patients implanted with RNS at our institution and identified three who originally presented with NORSE. Through chart review, we retrieved objective and subjective information related to their presentation, workup, and outcomes including patient-reported seizure frequency. We reviewed electrocorticography (ECoG) data to estimate seizure burden at 3, 6, 12, and 24 months following RNS implantation. We performed a review of literature concerning neurostimulation in NORSE. RESULTS: Use of RNS to treat DRE following NORSE was associated with reduced seizure burden and informed care by differentiating epileptic from non-epileptic events. CONCLUSIONS: Our single-center experience of three cases suggests that RNS is a safe and potentially effective treatment for DRE following NORSE. SIGNIFICANCE: This article reports outcomes of the largest case series of NORSE patients treated with RNS. Since patients with NORSE are at high risk of adverse neuropsychiatric and cognitive sequelae beyond seizures, a unique strength of RNS over other surgical options is the ability to distinguish ictal or peri-ictal from non-epileptic events.

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.

Electrocorticography Analysis in Patients With Dual Neurostimulators Supports Desynchronization as a Mechanism of Action for Acute Vagal Nerve Stimulator Stimulation.

PURPOSE: Both vagal nerve stimulation (VNS) and responsive neurostimulation (RNS System) are treatment options for medically refractory focal epilepsy. The mechanism of action of both devices remains poorly understood. Limited prior evidence suggests that acute VNS stimulation may reduce epileptiform activity and cause EEG desynchronization on electrocorticography (ECoG). Our study aims to isolate effects of VNS on ECoG as recorded by RNS System in patients who have both devices, by comparing ECoG samples with and without acute VNS stimulation. METHODS: Ten 60-second ECoGs each from 22 individuals at 3 epilepsy centers were obtained-5 ECoGs with VNS "off" and 5 ECoGs with VNS "on." Electrocorticograps containing seizures or loss of telemetry connection artifact were excluded from analysis (total of 169 ECoGs were included). Electrocorticographs were analyzed for differences in spectral content by generating average spectrograms for "on" and "off" states and using a linear mixed-effects model to isolate effects of VNS stimulation. RESULTS: Acute VNS stimulation reduced average power in the theta band by 4.9%, beta band by 3.8%, and alpha band by 2.5%. The reduction in theta power reached statistical significance with a P value of <0.05. CONCLUSIONS: Our results provide evidence that acute VNS stimulation results in desynchronization of specific frequency bands (salient decrease in theta and beta bands, smaller decrease in alpha band) in ECoGs recorded by the RNS device in patients with dual (VNS and RNS) neurostimulators. This finding offers support for desynchronization as a theorized mechanism of action of VNS. Further research may lead to future improved neurostimulator efficacy by informing optimal stimulation programming parameters.

A Method of Intraoperative Registration Verification to Prevent Accuracy Errors in Robot-Assisted Stereotactic Electroencephalography Electrode Placement.

BACKGROUND: Robotic-assisted stereotactic electroencephalography (sEEG) electrode placement is increasingly common at specialized epilepsy centers. High accuracy and low complication rates are essential to realizing the benefits of sEEG surgery. The aim of this study was to describe for the first time in the literature a method for a stereotactic registration checkpoint to verify intraoperative accuracy during robotic-assisted sEEG and to report our institutional experience with this technique. METHODS: All cases performed with this technique since the adoption of robotic-assisted sEEG at our institution were retrospectively reviewed. RESULTS: In 4 of 111 consecutive sEEG operations, use of the checkpoint detected an intraoperative registration error, which was addressed before completion of sEEG electrode placement. CONCLUSIONS: The use of a registration checkpoint in robotic-assisted sEEG surgery is a simple technique that can prevent electrode misplacement and improve the safety profile of this procedure.

Concurrent brain-responsive and vagus nerve stimulation for treatment of drug-resistant focal epilepsy.

OBJECTIVE: Clinical trials of a brain-responsive neurostimulator, RNS® System (RNS), excluded patients with a vagus nerve stimulator, VNS® System (VNS). The goal of this study was to evaluate seizure outcomes and safety of concurrent RNS and VNS stimulation in adults with drug-resistant focal-onset seizures. METHODS: A retrospective multicenter chart review was performed on all patients with an active VNS and RNS who were treated for a minimum of 6 months with both systems concurrently. Frequency of disabling seizures at baseline before RNS, at 1 year after RNS placement, and at last follow-up were used to calculate the change in seizure frequency after treatment. Data on adverse events and complications related to each device were collected. RESULTS: Sixty-four patients from 10 epilepsy centers met inclusion criteria. All but one patient received RNS after VNS. The median follow-up time after RNS implantation was 28 months. Analysis of the entire population of patients with active VNS and RNS systems revealed a median reduction in seizure frequency at 1 year post-RNS placement of 43% with a responder rate of 49%, and at last follow-up a 64% median reduction with a 67% responder rate. No negative interactions were reported from the concurrent use of VNS and RNS. Stimulation-related side-effects were reported more frequently in association with VNS (30%) than with RNS (2%). SIGNIFICANCE: Our findings suggest that concurrent treatment with VNS and RNS is safe and that the addition of RNS to VNS can further reduce seizure frequency.

Nine-year prospective efficacy and safety of brain-responsive neurostimulation for focal epilepsy.

OBJECTIVE: To prospectively evaluate safety and efficacy of brain-responsive neurostimulation in adults with medically intractable focal onset seizures (FOS) over 9 years. METHODS: Adults treated with brain-responsive neurostimulation in 2-year feasibility or randomized controlled trials were enrolled in a long-term prospective open label trial (LTT) to assess safety, efficacy, and quality of life (QOL) over an additional 7 years. Safety was assessed as adverse events (AEs), efficacy as median percent change in seizure frequency and responder rate, and QOL with the Quality of Life in Epilepsy (QOLIE-89) inventory. RESULTS: Of 256 patients treated in the initial trials, 230 participated in the LTT. At 9 years, the median percent reduction in seizure frequency was 75% (p < 0.0001, Wilcoxon signed rank), responder rate was 73%, and 35% had a ≥90% reduction in seizure frequency. We found that 18.4% (47 of 256) experienced ≥1 year of seizure freedom, with 62% (29 of 47) seizure-free at the last follow-up and an average seizure-free period of 3.2 years (range 1.04-9.6 years). Overall QOL and epilepsy-targeted and cognitive domains of QOLIE-89 remained significantly improved (p < 0.05). There were no serious AEs related to stimulation, and the sudden unexplained death in epilepsy (SUDEP) rate was significantly lower than predefined comparators (p < 0.05, 1-tailed χ2). CONCLUSIONS: Adjunctive brain-responsive neurostimulation provides significant and sustained reductions in the frequency of FOS with improved QOL. Stimulation was well tolerated; implantation-related AEs were typical of other neurostimulation devices; and SUDEP rates were low. CLINICALTRIALSGOV IDENTIFIER: NCT00572195. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that brain-responsive neurostimulation significantly reduces focal seizures with acceptable safety over 9 years.

A single case design to examine short-term intracranial EEG patterns during focused meditation.

PURPOSE: This study used a multiple crossover ABAB single case design to examine intracranial EEG data during a breath awareness meditation and an active control task. RESULTS: Visual analyses suggest that a brief breath awareness mediation was consistently associated with increased alpha power when compared to the active control. Less consistent effects were found with theta, beta, and high gamma activity. Nonparametric tests provided additional support for this finding. CONCLUSIONS: Acquiring intracranial EEG patterns during a meditative state may provide more insight into the physiology of meditation with less contamination of high-frequency muscle activity. While access to intracranial EEG during meditation is rarely available, single case design studies are considered adaptations of interrupted time-series designs and can provide an experimental evaluation of intervention effects.

Marijuana use among patients with epilepsy at a tertiary care center.

The expansion of medical and recreational marijuana legalization facilitates patient access to cannabis, and many patients with epilepsy pursue marijuana as a treatment for seizures. We administered a nine-item survey on marijuana use to patients seen in an epilepsy clinic over a 9 month period at a tertiary care center in Oregon where recreational use was legalized in 2015. The majority of respondents (n = 39) reported cannabis use for the purpose of treating epilepsy (87.2%, n = 34), and strongly agreed (53.8%, n = 21) or agreed (28.2%, n = 11) that cannabis use improved seizure control. The most commonly selected cannabis strains were high cannabidiol (CBD) (30.8%, n = 12) or multiple types (30.8%, n = 12), with administration methods of smoking (66.7%, n = 26), edibles (48.7%, n = 19), and concentrates (43.6%, n = 17). More participants reported using marijuana with primarily CBD than primarily tetrahydrocannabinol (THC) or equal CBD:THC content, and very few women reported using marijuana with primarily THC compared with men (10% of female versus 47% of male respondents). Only 2 of 39 participants were able to give an exact dosage used in milligrams. Medical and recreational dispensaries were the most common cannabis sources, followed by homegrown and friends/family members. Although pharmaceutical CBD extract is now Food and Drug Administration (FDA)-approved for certain epilepsy types, access remains limited. Further research is needed to understand recreational cannabis use among patients with epilepsy while clinical research for pharmaceutical cannabis products continues.

Novel Use of Responsive Neurostimulation (RNS System) in the Treatment of Super Refractory Status Epilepticus.

There are very few randomized controlled trials studying treatment of super refractory status epilepticus (SE), despite estimated occurrence in about 15% of SE cases and its association with high morbidity and mortality rates. Small case series and case reports have described use of neurostimulation, including vagal nerve stimulation, transcranial magnetic stimulation, and deep brain stimulation, to treat super refractory SE when medical interventions have failed. To our knowledge, this is the first reported case of responsive neurostimulation being used to successfully treat a case of super refractory SE. A 37-year-old man with refractory focal epilepsy and a known focal cortical dysplasia involving motor cortex was implanted with an RNS System device after being in super refractory SE for 20 days. Responsive neurostimulation strip and depth electrodes were placed targeting the cortical dysplasia. Detection and stimulation parameters were adjusted over a 14-day period, as medications were gradually weaned. Seizures abated 15 days after implant, 24 hours after stimulation parameters were configured to mimic seizure offset pattern. Seizure remission was sustained, allowing the patient to be weaned off sedating medications and discharged to a rehabilitation facility. At 6 weeks of follow-up, the patient was near his neurologic baseline with no focal deficits.

Let's Talk About Sex: Integrating Sex as a Biological Variable Into Epilepsy Research.

There is a long history of underrepresentation of women and female animals being studied in scientific research, which has resulted in gaps in knowledge and at times, inaccurate clinical recommendations. There is a gradual shift in the mindset of the scientific community on this issue, in part related to policy changes enacted by the National Institute of Health (NIH). Sex must now be accounted for as a biological variable in both basic and clinical research. This review discusses the history of evolving policies on inclusion of sex-informed data in scientific research, and the ways in which epilepsy researchers can approach future studies in a manner that takes sex as a biological variable into account.

Medication adherence in women with epilepsy who are planning pregnancy.

OBJECTIVE: This study examines medication adherence among women with epilepsy via use of an electronic diary, as part of a prospective multicenter observational study designed to evaluate fertility in women with epilepsy (WWE) versus age-matched controls. METHODS: WWE and healthy age-matched controls, seeking pregnancy, were given an iPod Touch using a customized mobile application (the WEPOD App) for daily data tracking. Eighty-six WWE tracked seizures and antiepileptic drugs (AEDs). Tracking of nonepilepsy medications was optional. Diary data were counted from enrollment date until date of delivery, or up to 12 months if pregnancy was not achieved. Each day that subjects reported missing one or more AED was counted as nonadherence. Because adherence can only be determined in women who track consistently, we elected to include adherence data only for women who tracked >80% of days in the study. RESULTS: Approximately 75% of WWE tracked >80% of days and were included in medication adherence data analysis. In this group, medication adherence rate was 97.71%; 44% of women admitted to missing an AED on at least 1 day. Among the subgroup of WWE who recorded nonepilepsy medications, AED adherence rate was 98.56%, versus 93.91% for non-AEDs. SIGNIFICANCE: The 75% compliance rate with an electronic diary suggests that it may be useful to track medication adherence in future studies and in the clinical setting. In those who tracked, the observed medication adherence rate was considerably higher than the 75% adherence rate seen in previous epilepsy studies. This might be explained in part by selection bias, but may also result from properties of the diary itself (daily reminders, real time feedback given to the provider). Women reported a higher rate of adherence to AEDs than to other prescribed medications and supplements, suggesting that perceived importance of medications likely influences medication adherence, and warrants future study.

Recent advances in epilepsy management.

PURPOSE OF REVIEW: Recent advances in our understanding of seizure generation have resulted in modified recommendations for when seizure treatment should be initiated, revisions to our definition of status epilepticus, and new pharmacological and neuromodulatory therapies. The goal of this review is to provide the anesthesiologist with an overview of the advancements they are most likely to encounter while providing clinical care. RECENT FINDINGS: There have been recent modifications to seizure definitions and treatment recommendations. These include the idea that treatment with antiepileptic therapy should be initiated after the first unprovoked seizure in individuals who are at high risk for another seizure, and that the idea that status epilepticus should be thought of as a two-phase process, related to an initial phase after which intervention should be started, and a second phase after which time risk of long-term sequelae is increased. Additionally, several new therapies have become available that have novel mechanisms of action, which are more efficacious and have fewer side-effects. SUMMARY: As knowledge about mechanisms of seizure generation has improved, there has been a concurrent evolution in our thinking about seizure-related definitions, and indications for initiation of treatment. Several next generation drug therapies with more specific targets have also become available. Taken together, there have been significant improvements in care options.