The Efficacy, Safety, and Outcomes of Brain-responsive Neurostimulation (RNS® System) therapy in older adults

Seize the Day or Let It Slip Away? The Dilemma of Epilepsy Surgery in Older Adults

Role of Comorbidities in Epilepsy Surgery Outcomes of Older Adults Tsai C, Taylor S, Thompson N, Vegh D, Bingaman W, Jehi L, Punia V. Epilepsia . 2024. doi:10.1111/epi.18103, PMID: 39283622. We lack knowledge about prognostic factors of resective epilepsy surgery (RES) in older adults (≥60 years), especially the role of comorbidities, which are a major consideration in managing the care of people with epilepsy (PWE). We analyzed a single-center cohort of 94 older adults (median age = 63.5 years, 52% females) who underwent RES between 2000 and 2021 with at least 6 months of post-surgical follow-up. Three-fourths of the study cohort had lesional magnetic resonance imaging and underwent temporal lobectomy. Fifty-four (57%) PWE remained seizure-free during a median follow-up of 3.5 years. Cox proportional hazard multivariable analysis showed that aura (hazard ratio [HR] = .52, 95% confidence interval [CI] = .27–1.00), single ictal electroencephalographic pattern (HR = .33, 95% CI = .17–.660), and Elixhauser Comorbidity Index (HR = 1.05, 95% CI = 1.00–1.10) were independently associated with seizure recurrence at last follow-up. A sensitivity analysis using the Charlson Combined Score (HR = 1.38, 95% CI = 1.03–1.84, p  = .027) confirmed the association of comorbidities with worse seizure outcome. Our findings provide a framework for a better informed discussion about RES prognosis in older adults. More extensive, multicenter cohort studies are needed to validate our findings and reduce hesitancy in pursuing RES in suitable older adults.

Role of Responsive Neurostimulation in Managing Drug-Resistant Epilepsy: A Systematic Review of Clinical Outcomes

Drug-resistant epilepsy remains a substantial challenge in neurology, affecting patients who do not respond to conventional antiepileptic drugs. Responsive neurostimulation (RNS) has emerged as a promising therapeutic approach, yet comprehensive reviews synthesizing its clinical outcomes are sparse. This systematic review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and involved a comprehensive database search through PubMed, Medline, Embase, the Cochrane Library, and Scopus, covering literature up to April 2024. The review targeted peer-reviewed articles evaluating the efficacy, safety, and quality of life impacts of RNS in patients with drug-resistant epilepsy. Key inclusion criteria encompassed clinical trials, cohort studies, and meta-analyses, while exclusion criteria included non-peer-reviewed and irrelevant studies. We identified five studies meeting our inclusion criteria. These studies collectively demonstrated that RNS significantly reduces seizure frequency and improves quality of life, while maintaining a favorable safety profile. Despite small sample sizes and potential selection biases, the benefits of RNS appeared consistent across diverse patient demographics. RNS represents a viable and effective treatment option for drug-resistant epilepsy, offering significant improvements in seizure control and patient quality of life. Future research should focus on long-term outcomes and refining patient selection to optimize the therapeutic benefits of RNS. The integration of RNS into standard epilepsy management protocols is recommended based on current evidence.

The comparison of DBS and RNS for adult drug-resistant epilepsy: a systematic review and meta-analysis

Objective

Neuromodulation has been proven to be a promising alternative treatment for adult patients with drug-resistant epilepsy (DRE). Deep brain stimulation (DBS) and responsive neurostimulation (RNS) were approved by many countries for the treatment of DRE. However, there is a lack of systematic studies illustrating the differences between them. This meta-analysis is performed to assess the efficacy and clinical characteristics of DBS and RNS in adult patients with DRE.

Methods

PubMed, Web of Science, and Embase were retrieved to obtain related studies including adult DRE patients who accepted DBS or RNS. The clinical characteristics of these patients were compiled for the following statistical analysis.

Results

A total of 55 studies (32 of DBS and 23 of RNS) involving 1,568 adult patients with DRE were included in this meta-analysis. There was no significant difference in seizure reduction and responder rate between DBS and RNS for DRE. The seizure reduction of DBS and RNS were 56% (95% CI 50-62%, p > 0.05) and 61% (95% CI 54-68%, p > 0.05). The responder rate of DBS and RNS were 67% (95% CI 58-76%, p > 0.05) and 71% (95% CI 64-78%, p > 0.05). Different targets of DBS did not show significant effect on seizure reduction (p > 0.05). Patients with DRE who accepted DBS were younger than those of RNS (32.9 years old vs. 37.8 years old, p < 0.01). The mean follow-up time was 47.3 months for DBS and 39.5 months for RNS (p > 0.05).

Conclusion

Both DBS and RNS are beneficial and alternative therapies for adult DRE patients who are not eligible to accept resection surgery. Further and larger studies are needed to clarify the characteristics of different targets and provide tailored treatment for patients with DRE.

Epilepsy surgery in adults older than 50 years: A systematic review and meta-analysis

OBJECTIVE

Despite the general safety and efficacy of epilepsy surgery, there is evidence that epilepsy surgery remains underutilized. Although there are an increasing number of studies reporting epilepsy surgery in older adults, there is no consensus on whether epilepsy surgery is efficacious or safe for this population. Our objective was to systematically assess the efficacy as well as safety of resective surgery in people aged 50 years or older with drug-resistant epilepsy.

METHODS

We considered studies that examine the efficacy and safety of epilepsy surgery in adults aged 50 years and older. Study eligibility was limited to studies carried out after 1990, with a minimum of 10 participants and 6 months of follow-up. We searched the following databases for published studies: Ovid MEDLINE, Ovid Embase, Cumulative Index to Nursing and Allied Health Literature, PsychInfo, and Web of Science Conference Proceedings Citation Index - Science. The risk of bias of each included study was independently assessed by two reviewers using the MINORS (Methodological Index for Non-Randomized Studies) instrument.

RESULTS

Eleven case series and 14 cohort studies met the criteria for inclusion, for a total of 1111 older adults who underwent epilepsy surgery along with 4111 adults younger than 50 years as control groups. The pooled cumulative incidence of older adults achieving seizure freedom after resective surgery was 70.1% (95% confidence interval [CI] = 65.3-74.7). There was no evident difference in the incidence of seizure freedom among older adults as compared to younger adults (risk ratio [RR] = 1.05, 95% CI = .97-1.14) in cohort studies. The pooled cumulative incidence of perioperative complications in older adults was 26.2% (95% CI = 21.3-31.7). Among them, 7.5% (95% CI = 5.8-9.5) experienced major complications. Older adults were significantly more at risk of experiencing any complication than younger adults (RR = 2.8, 95% CI = 1.5-5.4).

SIGNIFICANCE

Despite important considerations, epilepsy surgery may be considered appropriate among carefully selected individuals older than 50 years.

Trends in the Utilization of Surgical Modalities for the Treatment of Drug-Resistant Epilepsy: A Comprehensive 10-Year Analysis Using the National Inpatient Sample

BACKGROUND AND OBJECTIVES

Epilepsy is considered one of the most prevalent and severe chronic neurological disorders worldwide. Our study aims to analyze the national trends in different treatment modalities for individuals with drug-resistant epilepsy and investigate the outcomes associated with these procedural trends in the United States.

METHODS

Using the National Inpatient Sample database from 2010 to 2020, patients with drug-resistant focal epilepsy who underwent laser interstitial thermal therapy (LITT), open surgical resection, vagus nerve stimulation (VNS), or responsive neurostimulation (RNS) were identified. Trend analysis was performed using piecewise joinpoint regression. Propensity score matching was used to compare outcomes between 10 years prepandemic before 2020 and the first peak of the COVID-19 pandemic.

RESULTS

This study analyzed a total of 33 969 patients with a diagnosis of drug-resistant epilepsy, with 3343 patients receiving surgical resection (78%), VNS (8.21%), RNS (8%), and LITT (6%). Between 2010 and 2020, there was an increase in the use of invasive electroencephalography monitoring for seizure zone localization (P = .003). There was an increase in the use of LITT and RNS (P < .001), while the use of surgical resection and VNS decreased over time (P < .001). Most of these patients (89%) were treated during the pre-COVID pandemic era (2010-2019), while a minority (11%) underwent treatment during the COVID pandemic (2020). After propensity score matching, the rate of pulmonary complications, postprocedural hematoma formation, and mortality were slightly higher during the pandemic compared with the prepandemic period (P = .045, P = .033, and P = .026, respectively).

CONCLUSION

This study indicates a relative decrease in the use of surgical resections, as a treatment for drug-resistant focal epilepsy. By contrast, newer, minimally invasive surgical approaches including LITT and RNS showed gradual increases in usage.

Low Power EEG Data Encoding for Brain Neurostimulation Implants

Neurostimulation devices applied for the treatment of epilepsy that collect, encode, temporarily store, and transfer electroencephalographic (EEG) signals recorded intracranially from epileptic patients, suffer from short battery life spans. The principal goal of this study is to implement strategies for low power consumption rates during the device’s smooth and uninterrupted operation as well as during data transmission. Our approach is organised in three basic levels. The first level regards the initial modelling and creation of the template for the following two stages. The second level regards the development of code for programming integrated circuits and simulation. The third and final stage regards the transmitter’s implementation at the evaluation level. In particular, more than one software and device are involved in this phase, in order to achieve realistic performance. Our research aims to evolve such technologies so that they can transmit wireless data with simultaneous energy efficiency.

Chronic electroencephalography in epilepsy with a responsive neurostimulation device: current status and future prospects

INTRODUCTION

Implanted neurostimulation devices are gaining traction as therapeutic options for people with certain forms of drug-resistant focal epilepsy. Some of these devices enable chronic electroencephalography (cEEG), which offers views of the dynamics of brain activity in epilepsy over unprecedented time horizons.

AREAS COVERED

This review focuses on clinical insights and basic neuroscience discoveries enabled by analyses of cEEG from an exemplar device, the NeuroPace RNS® System. Applications of RNS cEEG covered here include counting and lateralizing seizures, quantifying medication response, characterizing spells, forecasting seizures, and exploring mechanisms of cognition. Limitations of the RNS System are discussed in the context of next-generation devices in development.

EXPERT OPINION

The wide temporal lens of cEEG helps capture the dynamism of epilepsy, revealing phenomena that cannot be appreciated with short duration recordings. The RNS System is a vanguard device whose diagnostic utility rivals its therapeutic benefits, but emerging minimally invasive devices, including those with subscalp recording electrodes, promise to be more applicable within a broad population of people with epilepsy. Epileptology is on the precipice of a paradigm shift in which cEEG is a standard part of diagnostic evaluations and clinical management is predicated on quantitative observations integrated over long timescales.

The Efficacy, Safety, and Outcomes of Brain-responsive Neurostimulation (RNS® System) therapy in older adults

Objectives

The gold standard for the management of drug‐resistant focal epilepsy (DRE) is resection of epileptogenic zone. However, some patients may not be candidates for resection. Responsive neurostimulation is approved in patients above 18 years of age for such patients. We aimed to investigate whether RNS outcomes and safety varied based on age.

Methods

We performed a single‐center retrospective cohort study of patients with DRE who were treated with RNS between May 2008 and February 2020. We included patients who had been implanted with RNS for >6 months (N = 55), dividing them into older (N = 11) and younger adults (N = 44) depending on implantation age (≥50 and <50 years, respectively).

Results

Mean age at implantation in older adults was 54.9 ± 3.5 years. Seizure onset age, epilepsy duration, and comorbidities were significantly higher in older adults ( P < .01). Stimulation parameters, treatment duration, and median seizure frequency reduction (76% in older vs 50% in younger adults) were statistically comparable between the two cohorts. Posttreatment, antiseizure medication burden was significantly decreased in older compared with younger adults (P = .048). Postoperative and delayed adverse events among older adults were mild. Compared with three younger adults, none of the older adults required device explantation due to surgical site infection.

Conclusion

Our study suggests that older adults treated with the RNS System achieve seizure outcomes comparable to younger adults with the additional benefit of a significant postimplantation medication reduction. With efficacy and safety similar to younger adults, brain‐responsive neurostimulation was well‐tolerated in older adults.