Efficacy and safety of VNS therapy or continued medication management for treatment of adults with drug-resistant epilepsy: systematic review and meta-analysis

Can transcutaneous auricular vagus nerve stimulation be considered a viable adjuntive therapy in drug-resistant epilepsy? A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

Transcutaneous auricular vagal nerve stimulation (tVNS) has been investigated as a potential non-invasive therapy in addition to standard medical care in patients with drug-resistant epilepsy (DRE). This meta-analysis evaluates the efficacy and safety of tVNS compared to sham stimulation in patients with DRE.

METHODS

A systematic search was conducted in three electronic databases (PubMed, Scopus, Cochrane) to identify randomized controlled trials (RCTs) comparing tVNS versus sham stimulation for the treatment of DRE. The Cochrane risk of bias tool for randomized trials was utilized for quality assessment.

RESULTS

Four RCTs, comprising 368 patients, with 232 patients in the tVNS group, were included. The meta-analysis revealed that tVNS significantly reduces seizure frequency, as expressed by mean monthly seizure number (mean difference [MD] -3.01, 95 % confidence interval [CI] [-5.37 to -0.65], p < 0.01, I2 = 0 %) and percentage seizure reduction (MD 17.57 %, 95 % CI [1.90 to 33.25], p = 0.03, I2 = 0 %) at the end of treatment. The analysis also indicated a potential effect on responder rate (odds ratio 2.00, 95 % CI [0.98 to 4.05], p = 0.06, I2 = 42 %), although not statistically significant. No significant differences between groups were found regarding seizure freedom, depression, and QOL. Adverse events reported were mostly mild and transient, with no significant differences between groups and comparable discontinuation rates.

CONCLUSIONS

This meta-analysis supports the efficacy and safety of tVNS as an adjunctive therapy for the treatment of DRE. Due to significant methodological concerns in some of the included studies, well-designed RCTs are needed to investigate the efficacy of tVNS on seizure and non-seizure outcomes in patients with DRE.

Dynamic changes in comorbid conditions following vagus nerve stimulation for epilepsy

BACKGROUND

Vagus nerve stimulation (VNS) has been widely used in the clinical treatment of epilepsy, while its effects on comorbidities in epilepsy remain incompletely elucidated. This study aimed to evaluate the impact of VNS on comorbidities and quality of life in adult patients with epilepsy.

METHODS

A longitudinal, multicenter cohort study was conducted from 2021 to 2024 among adult patients with epilepsy who underwent VNS implantation. We enrolled 128 participants from 83 hospitals. The inclusion criteria were patients over 18 years old, diagnosed with epilepsy according to the 2014 International League Against Epilepsy guidelines, and having complete data from at least two follow-up visits. Standard assessment tools, including diagnosis according to International Classification of Diseases, 10th Edition (ICD-10), Neurological Disorders Depression Inventory for Epilepsy (NDDI-E), Generalized Anxiexy Disorde-7 (GAD-7), Pittsburgh Sleep Quality Index (PSQI), and Quality of Life in Epilepsy-31 (QOLIE-31) were used to evaluate comorbidities and quality of life. Statistical analysis was performed using SPSS 26.0. The major clinical measurements were changes in the scales above before and after VNS implantation during follow-up. Generalized estimation model was applied to illustrate the effect over time an its relation to seizure control.

RESULTS

A total of 113 participants met the inclusion criteria. Baseline characteristics were comparable between the comorbidity and non-comorbidity groups in terms of gender, seizure onset, age at VNS implantation, seizure types, or the number of antiseizure medications used. Significant improvements were observed from the implantation to the end of follow-up. The PSQI score decreased from 5.43 ± 3.60 to 4.44 ± 3.14 (P < 0.01), indicating better sleep quality. Depressive symptoms (NDDI-E) and anxiety symptoms (GAD-7) decreased significantly, with scores dropping from 6.49 ± 4.67 to 4.83 ± 4.37 (P < 0.01) and from 7.15 ± 5.06 to 4.95 ± 3.69 (P < 0.01), respectively. The QOLIE-31 score increased from 54.40 ± 15.70 to 61.33 ± 16.19 (P < 0.01), suggesting improved quality of life. Further analysis indicated that in the early second postoperative follow-up (1 month after implantation), the scales had already improved significantly (P < 0.001 for PSQI and QOLIE-31, P = 0.006 for NDDI-E and GAD-7). We did not find any statistically significant difference between patients with comorbidity and those without on the efficacy of any scales in this study. The efficacy of VNS on the four scales above was related to follow-up time, with a slightly rebound at the last two follow-ups. The NDDI-E as well as the GAD-7 scores were related to better seizure control according to the GEE model. Higher stimulation currents over 1 mA did not improve the efficacy of VNS on the comorbid conditions.

CONCLUSIONS

VNS implantation significantly improved sleep quality, mental health, and overall quality of life in adult patients with epilepsy. Such effects could be observed shortly after the implantation and were mostly long-lasting. Further research is needed to validate its long-term effects.

Long-Term Efficacy and Quality-of-Life Changes After Vagus Nerve Stimulation in Adult Patients With Drug-Resistant Epilepsy

BACKGROUND AND PURPOSE

There is a current need to understand the efficacy and quality of life (QoL) outcomes of vagus nerve stimulation (VNS). Identifying patients most likely to benefit from VNS could aid in their selection, reduce side effects, and improve outcomes. Here we studied clinical and QoL outcomes after VNS in patients with drug-resistant epilepsy and attempted to identify response predictors.

METHODS

This was a retrospective study of 55 patients with drug-resistant epilepsy treated surgically during 2004-2018, 40 of whom were eligible for inclusion in the analysis. All surgeries were performed using a standard protocol by a neurosurgeon experienced in epilepsy treatment after referral by an attending neurologist. Data were collected from medical records and through a 28-item questionnaire on seizure frequency, duration, and strength before and after VNS, as were the number and type of postoperative complications and their significance to the patient, and QoL based on the 31-item Quality of Life in Epilepsy questionnaire.

RESULTS

Improvements in seizure frequency, duration, and strength were observed in 65% of the patients with drug-resistant epilepsy treated using VNS. The most common complication was hoarseness (70%), and complications were poorly tolerated by 12% of the patients. Repeated surgery to replace batteries or electrodes was required in 20% of the patients. Health status was the only QoL parameter significantly impacted by VNS. No significant efficacy predictors were identified.

CONCLUSIONS

Efficacy across the first month of treatment is a strong indicator of long-term outcomes of VNS. The stimulator can be removed if it does not provide any benefit.

Significant reduction of seizure frequency in patients with drug-resistant epilepsy by vagus nerve stimulation: Systematic review and meta-analysis

BACKGROUND

Epilepsy is a major neurological disorder, typically managed with Anti-Seizure Medication (ASM). Nevertheless, a substantial 30 % of patients did not respond satisfactorily to ASMs, classifying their condition as Drug-Resistant Epilepsy (DRE). Vagus Nerve Stimulation (VNS) was recommended as a potential solution.

OBJECTIVE

To evaluate clinical efficacy of VNS on patients with DRE in reduction of seizures through a systematic review and meta-analysis using a random effects model.

METHODS

A systematic search was done from PubMed, ScienceDirect, Cochrane Library and Google Scholar databases on observational studies and randomized controlled trials (RCTs) for the clinical effectiveness of VNS among DRE patients. A meta-analysis was performed to obtain the pooled estimate of the clinical effectiveness of VNS in terms of seizure reduction and the odds ratio (OR) for patients achieving > 50 % seizure reduction. Heterogeneity was assessed using visual inspection of forest plots and I2 statistic.

RESULTS

A total of 1023 articles were retrieved from the electronic search. After removing duplicates, non-relevance and non-availability of efficacy data, 28 articles were included in the final analysis. Of these, 9 are RCTs and 19 are observational studies. The pooled estimate of > 50 % seizure reduction was 0.46 (95 % CI: 0.40-0.51) and the pooled estimate of the OR comparing > 50 % vs ≤ 50 % seizure reduction was 0.76 (95 % CI: 0.44-1.29).

CONCLUSION

Our meta-analysis showed that 46 % of DRE patients have experienced ≥ 50 % seizure reduction with VNS treatment. It should be considered in patients in whom ASM has failed or who continue to experience seizures after medication.

Treatment of Seizures in People with Intellectual Disability

There is a synergistic relationship between epilepsy and intellectual disability (ID), and the approach to managing people with these conditions needs to be holistic. Epilepsy is the main co-morbidity associated with ID, and clinical presentation tends to be complex, associated with higher rates of treatment resistance, multi-morbidity and premature mortality. Despite this relationship, there is limited level 1 evidence to inform treatment choice for this vulnerable population. This review updates the current evidence base for anti-seizure medication (ASM) prescribing for people with ID. Recommendations are made on the basis of evidence and expert clinical opinion and summarised into a Traffic Light System for accessibility. This review builds on work developed through UK's Royal College of Psychiatrists, Faculty of Intellectual Disability Psychiatry and includes newer pragmatic data from the Cornwall UK Ep-ID Research Register, a national research register for England and Wales that has been in existence for the last 10 years. The Register acts as a source for an in-depth exploration of the evidence base for prescribing 'newer' (third generation, specifically post-2004) ASMs. Its findings are discussed and compared. A practical approach to prescribing and choosing ASMs is recommended on the based evidence. This approach considers the drug profile, including adverse effects and clinical characteristics. The review also details newer specialist ASMs restricted to certain epilepsy syndromes, and potential future ASMs that may be available soon. For completeness, we also explore non-pharmacological interventions, including surgeries, to support epilepsy management.

Vagus nerve stimulation in lesional and Non-Lesional Drug-Resistant focal onset epilepsies

PURPOSE

Drug-resistant epilepsy (DRE) affects one-third of patients with focal epilepsy. A large portion of patients are not candidates for epilepsy surgery, thus alternative options, such as vagus nerve stimulation (VNS), are proposed. Our objective is to study the effect of vagus nerve stimulation on lesional versus non-lesional epilepsies.

METHODS

This is a retrospective cohort study in a single center in London, Ontario, which includes patients with DRE implanted with VNS, implanted between 1997-2018 and the date of analysis is December 2023.

PARTICIPANTS

Patients implanted with VNS were classified by lesional (VNS-L) and non-lesional (VNS-NL) based on their MRI head findings. We further subdivided the VNS groups into patients with VNS alone versus those who also had additional epilepsy surgeries.

RESULTS

A total of 29 patients were enrolled in the VNS-L, compared to 29 in the VNS-NL. The median age of the patients in the study was 31.8 years, 29.31 % were men (N = 17). 41.4 % (n = 12) of the patients were VNS responders (≥50 % seizure reduction) in the VNS-L group compared to 62.0 % (n = 18) in the VNS-NL group (p = 0.03). When other epilepsy surgeries were combined with VNS in the VNS-L group, the median rate of seizure reduction was greater (72.4 (IQR 97.17-45.88) than the VNS-NL group 53.9 (IQR 92.22-27.92); p = 0.27).

CONCLUSIONS

VNS is a therapeutic option for patients with lesional epilepsy, with slightly inferior results compared to patients with non-lesional epilepsy. Patients implanted with VNS showed higher seizure reduction rates if they had previous epilepsy surgeries. This study demonstrates that VNS in lesional epilepsies can be an effective treatment.

Long-term effects of vagus nerve stimulation on EEG aperiodic components in patients with drug-resistant epilepsy

Background

Drug-resistant epilepsy (DRE) affects approximately one-third of epilepsy patients who do not achieve adequate seizure control with medication. Vagus nerve stimulation (VNS) is an adjunctive therapy for DRE, but its long-term effects on cortical excitability remain unclear.

Objectives

This study aims to elucidate the long-term effects of VNS on electroencephalography (EEG) aperiodic components in patients with DRE. Our objective is to identify biomarkers that can serve as indicators of therapeutic efficacy and provide mechanistic insights into the underlying neural processes.

Design

This longitudinal observational study focused on patients with DRE undergoing VNS therapy at Sanbo Brain Hospital. The reduction in seizure frequency rates was quantified over short-term (⩽1 year), medium-term (1-3 years), and long-term (⩾3 years) intervals to assess the therapeutic efficacy of VNS. Both the periodic and aperiodic components of EEG data were analyzed.

Methods

Advanced signal processing techniques were utilized to parameterize the periodic and aperiodic components of EEG data, focusing particularly on "offset" and "exponent." These measures were compared before and after VNS therapy. Correlation analyses were conducted to explore the relationship between these EEG parameters and clinical outcomes.

Results

In all, 18 patients with DRE participated in this study. During the long-term follow-up period, the responder rate was 55.56%. Significant decreases were observed in aperiodic offset (p = 0.022) and exponent (p = 0.039) among responders. The impact of age on these results was not significant. Correlation analyses revealed a negative association between therapeutic efficacy and a decrease in offset (R = -0.546, p = 0.019) and exponent (R = -0.636, p = 0.019).

Conclusion

EEG aperiodic parameters, including offset and exponent, have the potential to serve as promising biomarkers for evaluating the efficacy of VNS. An understanding of the regulatory influence of VNS on cortical excitability through these aperiodic parameters could provide a basis for the development of more effective stimulation parameters and therapeutic strategies.

Long-Term Outcome in Adult Patients with Drug-Resistant Epilepsy Submitted to Vagus Nerve Stimulation

Epilepsy treatment primarily involves antiseizure medications (ASMs) to eliminate seizures and improve the quality of life, but many patients develop drug-resistant epilepsy (DRE), necessitating alternative interventions. This study aimed to evaluate the long-term efficacy and safety of vagus nerve stimulation (VNS) in managing DRE. We retrospectively analyzed data from 105 adult patients treated at Agostino Gemelli Hospital from 1994 to 2022. Among the 73 patients with follow-up data, 80.8% were responders, experiencing significant reductions in seizure frequency over an average follow-up period of 9.4 years. Although 19.2% were non-responders, many of these patients still opted for generator replacements due to improvements in quality of life, such as fewer falls and shorter post-ictal periods. The overall complication rate was 12.3%, with most complications being mild and manageable. These findings suggest that VNS offers substantial long-term benefits for patients with DRE, improving seizure control and quality of life. This study underscores the importance of VNS as a viable long-term treatment option for DRE, highlighting its potential to significantly enhance patient outcomes and quality of life.

Using neural biomarkers to personalize dosing of vagus nerve stimulation

BACKGROUND

Vagus nerve stimulation (VNS) is an established therapy for treating a variety of chronic diseases, such as epilepsy, depression, obesity, and for stroke rehabilitation. However, lack of precision and side-effects have hindered its efficacy and extension to new conditions. Achieving a better understanding of the relationship between VNS parameters and neural and physiological responses is therefore necessary to enable the design of personalized dosing procedures and improve precision and efficacy of VNS therapies.

METHODS

We used biomarkers from recorded evoked fiber activity and short-term physiological responses (throat muscle, cardiac and respiratory activity) to understand the response to a wide range of VNS parameters in anaesthetised pigs. Using signal processing, Gaussian processes (GP) and parametric regression models we analyse the relationship between VNS parameters and neural and physiological responses.

RESULTS

Firstly, we illustrate how considering multiple stimulation parameters in VNS dosing can improve the efficacy and precision of VNS therapies. Secondly, we describe the relationship between different VNS parameters and the evoked fiber activity and show how spatially selective electrodes can be used to improve fiber recruitment. Thirdly, we provide a detailed exploration of the relationship between the activations of neural fiber types and different physiological effects. Finally, based on these results, we discuss how recordings of evoked fiber activity can help design VNS dosing procedures that optimize short-term physiological effects safely and efficiently.

CONCLUSION

Understanding of evoked fiber activity during VNS provide powerful biomarkers that could improve the precision, safety and efficacy of VNS therapies.

High-precision stereotactic irradiation for focal drug-resistant epilepsy versus standard treatment: a randomized waitlist-controlled trial (the PRECISION trial)

INTRODUCTION

The standard treatment for patients with focal drug-resistant epilepsy (DRE) who are not eligible for open brain surgery is the continuation of anti-seizure medication (ASM) and neuromodulation. This treatment does not cure epilepsy but only decreases severity. The PRECISION trial offers a non-invasive, possibly curative intervention for these patients, which consist of a single stereotactic radiotherapy (SRT) treatment. Previous studies have shown promising results of SRT in this patient population. Nevertheless, this intervention is not yet available and reimbursed in the Netherlands. We hypothesize that: SRT is a superior treatment option compared to palliative standard of care, for patients with focal DRE, not eligible for open surgery, resulting in a higher reduction of seizure frequency (with 50% of the patients reaching a 75% seizure frequency reduction at 2 years follow-up).

METHODS

In this waitlist-controlled phase 3 clinical trial, participants are randomly assigned in a 1:1 ratio to either receive SRT as the intervention, while the standard treatments consist of ASM continuation and neuromodulation. After 2-year follow-up, patients randomized for the standard treatment (waitlist-control group) are offered SRT. Patients aged ≥ 18 years with focal DRE and a pretreatment defined epileptogenic zone (EZ) not eligible for open surgery will be included. The intervention is a LINAC-based single fraction (24 Gy) SRT treatment. The target volume is defined as the epileptogenic zone (EZ) on all (non) invasive examinations. The seizure frequency will be monitored on a daily basis using an electronic diary and an automatic seizure detection system during the night. Potential side effects are evaluated using advanced MRI, cognitive evaluation, Common Toxicity Criteria, and patient-reported outcome questionnaires. In addition, the cost-effectiveness of the SRT treatment will be evaluated.

DISCUSSION

This is the first randomized trial comparing SRT with standard of care in patients with DRE, non-eligible for open surgery. The primary objective is to determine whether SRT significantly reduces the seizure frequency 2 years after treatment. The results of this trial can influence the current clinical practice and medical cost reimbursement in the Netherlands for patients with focal DRE who are not eligible for open surgery, providing a non-invasive curative treatment option.

TRIAL REGISTRATION

Clinicaltrials.gov Identifier: NCT05182437. Registered on September 27, 2021.

Magnetogenetic cell activation using endogenous ferritin

The ability to precisely control the activity of defined cell populations enables studies of their physiological roles and may provide therapeutic applications. While prior studies have shown that magnetic activation of ferritin-tagged ion channels allows cell-specific modulation of cellular activity, the large size of the constructs made the use of adeno-associated virus, AAV, the vector of choice for gene therapy, impractical. In addition, simple means for generating magnetic fields of sufficient strength have been lacking. Toward these ends, we first generated a novel anti-ferritin nanobody that when fused to transient receptor potential cation channel subfamily V member 1, TRPV1, enables direct binding of the channel to endogenous ferritin in mouse and human cells. This smaller construct can be delivered in a single AAV and we validated that it robustly enables magnetically induced cell activation in vitro. In parallel, we developed a simple benchtop electromagnet capable of gating the nanobody-tagged channel in vivo. Finally, we showed that delivering these new constructs by AAV to pancreatic beta cells in combination with the benchtop magnetic field delivery stimulates glucose-stimulated insulin release to improve glucose tolerance in mice in vivo. Together, the novel anti-ferritin nanobody, nanobody-TRPV1 construct and new hardware advance the utility of magnetogenetics in animals and potentially humans.

Effectiveness of Seizure Dogs for People With Severe Refractory Epilepsy: Results From the EPISODE Study

BACKGROUND AND OBJECTIVES

The aim of this study was to evaluate whether people living with severe medically refractory epilepsy (PSRE) benefit from a seizure dog.

METHODS

An individual-level stepped-wedge randomized controlled trial was conducted. The study was conducted in the Netherlands among adults with daily to weekly seizures. All participants were included simultaneously (on June 1, 2019) while receiving usual care. Then, during the 36-month follow-up, they received a seizure dog in a randomized sequence. Participants kept a seizure diary and completed 3-monthly surveys. Seizure frequency was the primary outcome. Secondary outcomes included seizure-free days, seizure severity, health-related quality of life (HRQoL), and well-being. Data were analyzed using generalized linear mixed modeling (GLMM). The models assumed a delayed intervention effect, starting when the seizure dog reached an advanced stage of training. Effects were calculated as changes per 28-day period with the intervention.

RESULTS

Data were collected from 25 participants, of whom 20 crossed over to the intervention condition. The median follow-up was 19 months with usual care and 12 months with the intervention. On average, participants experienced 115 (SD 164) seizures per 28-day period in the usual care condition and 73 (SD 131) seizures in the intervention condition. Seven participants achieved a reduction of 50% or more at the end of follow-up. GLMM indicated a 3.1% decrease in seizure frequency for each consecutive 28-day period with the intervention (0.969, 95% CI 0.960-0.977). Furthermore, an increase in the number of seizure-free days was observed (1.012, 95% CI 1.009, 1.015), but no effect on seizure severity measured with the NHS3. Generic HRQoL scores improved, as reflected in the decrease in EQ-5D-5L utility decrement (0.975, 95% CI 0.954-0.997). Smaller improvements were observed on overall self-rated HRQoL, epilepsy-specific HRQoL, and well-being, measured with the EQ VAS, QOLIE-31-P, and ICECAP-A, respectively.

DISCUSSION

Seizure dogs reduce seizure frequency, increase the number of seizure-free days, and improve the quality of life of PSRE. The magnitude of the effect on generic HRQoL indicates that seizure dogs benefit PSRE beyond the impact on seizure frequency alone. Early discontinuation of seizure dog partnerships suggests that this intervention is not suitable for all PSRE and requires further study.

TRIAL REGISTRATION INFORMATION

This study was registered in the Dutch Trial Register (NL6682) on November 28, 2017. Participants were enrolled on June 1, 2019.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that seizure dogs are associated with a decrease in seizure frequency in adult patients with medically refractory epilepsy.

Refractory status epilepticus arrested by vagus nerve stimulation

A 54-year-old man developed altered mental state and generalised tonic-clonic seizures after 1 week of upper respiratory tract symptoms and diarrhoea, having been previously well. His MR scan of brain showed multifocal progressive T2 cortical signal changes. He was diagnosed with new-onset refractory status epilepticus (NORSE), initially treated as being secondary to autoimmune/paraneoplastic limbic encephalitis, although subsequent investigations were negative. His seizures and electrographic epileptiform activity continued despite escalating doses of antiseizure medications, immunosuppression with corticosteroids, immunoglobulins, plasma exchange and rituximab, and thereafter anaesthetic agents. A vagus nerve stimulator (VNS) was implanted 6 weeks after admission and its voltage rapidly increased over 4 days; his seizure activity resolved in the third week after VNS implantation. This case highlights the role of VNS in the early management of NORSE.

Vagus nerve stimulation in medically refractory epilepsy: Adverse effects and clinical correlates

OBJECTIVES

To assess the frequency of adverse effects among pediatric and adult patients and the clinical variables associated with a higher probability of developing side effects.

METHODS

This retrospective study enrolled pediatric and adult patients who underwent Vagus nerve stimulation (VNS) implantation at our institution and had documented follow-up during clinic visits for at least 6 months after implantation. Data collected included demographic information, epilepsy diagnosis, and device data.

RESULTS

A total of 43 patients with drug-resistant epilepsy who received a VNS device at our institution were enrolled. The median follow-up period was 12 months. Fourteen patients (32.55%) reported no side effects from VNS therapy. Side effects ranged from mild to severe, with significant side effects observed in 8 patients. Data on therapy efficacy were collected, and 10 patients (23.26%) reported no change in seizure frequency following device implantation.

CONCLUSION

This study demonstrates that VNS is an important adjunct treatment option for epilepsy patients. Dysphagia and dyspnea can be significant adverse effects leading to treatment discontinuation, aspiration pneumonia, intensive care unit (ICU) admission, and prolonged hospital stay. These effects are more frequent in patients with symptomatic generalized epilepsy, global developmental delay at baseline, previous ICU admissions, abnormal brain magnetic resonance imaging findings, and seizures with multiple semiologies.

Favorable combinations of antiseizure medication with vagus nerve stimulation to improve health-related quality of life in patients with epilepsy

BACKGROUND

Vagus nerve stimulation (VNS) is a non-pharmacological treatment of refractory epilepsy, which also has an antidepressive effect. The favorable combinations of VNS with specific mechanisms of action of antiseizure medication (ASM) on mood and health-related quality of life (HrQol) have not yet been studied. The objective was to identify favourable combinations of specific ASMs with VNS for the HrQoL and depression in refractory epilepsy.

METHODS

We performed an observational study including patients with refractory epilepsy and an implanted VNS (N = 151). In the first 24 months after VNS implantation, all patients were on stable ASM therapy. We used the standardized questionnaires QOLIE10, EQVAS and EQ5D to evaluate HrQoL as well as the Beck Depression Inventory (BDI). Multiple regression analysis was performed to evaluate the synergistic combinations of ASM with VNS for HrQoL.

RESULTS

At the year-two follow-up (N = 151, age 45.2 ± 17.0 years), significant improvement (p < 0.05) in BDI scores was found for combination of VNS with SV2A modulators (58.4 %) or AMPA antagonists (44.4 %). A significant increase of HrQoL by at least 30 % (p < 0.05) was measured for a combination of VNS with SV2A modulators (brivaracetam, levetiracetam) or slow sodium channel inhibitors (eslicarbazepine, lacosamide).

CONCLUSION

The results of our study suggests a favorable effect of the combination of SV2A modulators or slow sodium channel inhibitors with VNS on the HrQoL in comparison to other ASMs. Besides the possible synergistic effects on the seizure frequency, the amelioration of behavioral side effects of SV2A modulators by VNS is an important factor of HrQoL-improvement in these combinations.

The experience of applying vagus nerve stimulation in treatment of pharmacoresistant epilepsy

The article presents a clinical case of adult patient with pharmacoresistant epilepsy lacking focal cerebral morphological changes, who was surgically implanted with a vagus nerve stimulation (VNS) system. The results of 6 months-long treatment were analyzed. In addition, available publications were reviewed to evaluate effectiveness of the VNS system in different patient groups. Current clinical case was featured with significant positive dynamics revealed by regression of epileptic seizures and no recorded epileptiform activity based on electroencephalography during VNS stimulation. In the absence of morphological cerebral focal changes in adult patients, installation of the VNS system is an effective and safe method to control pharmacoresistant epilepsy.

Exploring the potential of vagus nerve stimulation in treating brain diseases: a review of immunologic benefits and neuroprotective efficacy

The vagus nerve serves as a critical connection between the central nervous system and internal organs. Originally known for its effectiveness in treating refractory epilepsy, vagus nerve stimulation (VNS) has shown potential for managing other brain diseases, including ischaemic stroke, traumatic brain injury, Parkinson's disease, and Alzheimer's disease. However, the precise mechanisms of VNS and its benefits for brain diseases are not yet fully understood. Recent studies have found that VNS can inhibit inflammation, promote neuroprotection, help maintain the integrity of the blood-brain barrier, have multisystemic modulatory effects, and even transmit signals from the gut flora to the brain. In this article, we will review several essential studies that summarize the current theories of VNS and its immunomodulatory effects, as well as the therapeutic value of VNS for brain disorders. By doing so, we aim to provide a better understanding of how the neuroimmune network operates and inspire future research in this field.

Effect of vagus nerve stimulation against generalized seizure and status epilepticus recurrence

Objective

Vagus nerve stimulation (VNS) is a palliative surgery for drug-resistant epilepsy. The two objectives of this study were to (1) determine the seizure type most responsive to VNS and (2) investigate the preventive effect on status epilepticus (SE) recurrence.

Methods

We retrospectively reviewed 136 patients with drug-resistant epilepsy who underwent VNS implantation. We examined seizure outcomes at 6, 12, and 24 months following implantation of VNS as well as at the last visit to the Juntendo Epilepsy Center. Univariate analysis and multivariate logistic regression models were used to estimate the prognostic factors.

Results

125 patients were followed up for at least 1 year after VNS implantation. The percentage of patients with at least a 50% reduction in seizure frequency compared with prior to VNS implantation increased over time at 6, 12, and 24 months after VNS implantation: 28, 41, and 52%, respectively. Regarding overall seizure outcomes, 70 (56%) patients responded to VNS. Of the 40 patients with a history of SE prior to VNS implantation, 27 (67%) showed no recurrence of SE. The duration of epilepsy, history of SE prior to VNS implantation and seizure type were correlated with seizure outcomes after VNS implantation in univariate analysis (p = 0.05, p < 0.01, and p = 0.03, respectively). In multivariate logistic regression analysis, generalized seizure was associated with VNS response [odds ratio (OR): 4.18, 95% CI: 1.13-15.5, p = 0.03]. A history of SE prior to VNS implantation was associated with VNS non-responders [(OR): 0.221, 95% CI: 0.097-0.503, p < 0.01]. The duration of epilepsy, focal to bilateral tonic-clonic seizure and epileptic spasms were not significantly associated with VNS responders (p = 0.07, p = 0.71, and p = 0.11, respectively).

Conclusion

Following 125 patients with drug-resistant epilepsy for an average of 69 months, 56% showed at least 50% reduction in seizure frequency after VNS implantation. This study suggests that generalized seizure is the most responsive to VNS, and that VNS may reduce the risk of recurrence of SE. VNS was shown to be effective against generalized seizure and also may potentially influence the risk of further events of SE, two marker of disease treatment that can lead to improved quality of life.

Neuropsychiatric Lyme Disease and Vagus Nerve Stimulation

Lyme disease, the most common tick-borne disease in the United States, is caused by infection with the spirochete Borrelia burgdorferi. While most patients with acute Lyme disease recover completely if treated with antibiotics shortly after the onset of infection, approximately 10-30% experience post-treatment symptoms and 5-10% have residual symptoms with functional impairment (post-treatment Lyme disease syndrome or PTLDS). These patients typically experience pain, cognitive problems, and/or fatigue. This narrative review provides a broad overview of Lyme disease, focusing on neuropsychiatric manifestations and persistent symptoms. While the etiology of persistent symptoms remains incompletely understood, potential explanations include persistent infection, altered neural activation, and immune dysregulation. Widely recognized is that new treatment options are needed for people who have symptoms that persist despite prior antibiotic therapy. After a brief discussion of treatment approaches, the article focuses on vagus nerve stimulation (VNS), a neuromodulation approach that is FDA-approved for depression, epilepsy, and headache syndromes and has been reported to be helpful for other diseases characterized by inflammation and neural dysregulation. Transcutaneous VNS stimulates the external branch of the vagus nerve, is minimally invasive, and is well-tolerated in other conditions with few side effects. If well-controlled double-blinded studies demonstrate that transcutaneous auricular VNS helps patients with chronic syndromes such as persistent symptoms after Lyme disease, taVNS will be a welcome addition to the treatment options for these patients.

Predictive factors for successful vagus nerve stimulation in patients with refractory epilepsy: real-life insights from a multicenter study

Introduction

Vagus nerve stimulation (VNS) therapy is an established treatment for patients with drug-resistant epilepsy that reduces seizure frequency by at least 50% in approximately half of patients; however, the characteristics of the patients with the best response have not yet been identified. Thus, it is important to identify the profile of patients who would have the best response to guide early indications and better patient selection.

Methods

This retrospective study evaluated vagus nerve stimulation (VNS) as an adjuvant therapy for patients with drug-resistant epilepsy from six epilepsy centers in Brazil. Data from 192 patients aged 2-66 years were analyzed, and all patients received at least 6 months of therapy to be included.

Results

Included patients were aged 2-66 years (25.6 ± 14.3), 105 (54.7%) males and 87 (45.8%) females. Median follow-up interval was 5 years (range, 2005-2018). Overall, the response rate (≥50% seizure reduction) after VNS implantation was 65.6% (126/192 patients). Most patients had 50-90% seizure reduction (60.9%) and nine patients became seizure-free. There were no serious complications associated with VNS implantation. The rate of a ≥ 50% seizure reduction response was significantly higher in patients with no history of neurosurgery. The presence of focal without generalized seizures and focal discharges on interictal EEG was associated with better response. Overall, etiological predictors of a better VNS response profile were tumors while a worse response to VNS was related to the presence of vascular malformations and Lennox-Gastaut Syndrome.

Discussion

We observed an association between a better response to VNS therapy no history of neurosurgery, focal interictal epileptiform activity, and focal seizure pattern. Additionally, it is important to highlight that age was not a determinant factor of the response, as children and adults had similar response rates. Thus, VNS therapy should be considered in both adults and children with DRE.

Neuroimmunomodulation of vagus nerve stimulation and the therapeutic implications

Vagus nerve stimulation (VNS) is a technology that provides electrical stimulation to the cervical vagus nerve and can be applied in the treatment of a wide variety of neuropsychiatric and systemic diseases. VNS exerts its effect by stimulating vagal afferent and efferent fibers, which project upward to the brainstem nuclei and the relayed circuits and downward to the internal organs to influence the autonomic, neuroendocrine, and neuroimmunology systems. The neuroimmunomodulation effect of VNS is mediated through the cholinergic anti-inflammatory pathway that regulates immune cells and decreases pro-inflammatory cytokines. Traditional and non-invasive VNS have Food and Drug Administration (FDA)-approved indications for patients with drug-refractory epilepsy, treatment-refractory major depressive disorders, and headaches. The number of clinical trials and translational studies that explore the therapeutic potentials and mechanisms of VNS is increasing. In this review, we first introduced the anatomical and physiological bases of the vagus nerve and the immunomodulating functions of VNS. We covered studies that investigated the mechanisms of VNS and its therapeutic implications for a spectrum of brain disorders and systemic diseases in the context of neuroimmunomodulation.

Cross-Frequency Coupling and Intelligent Neuromodulation

Cross-frequency coupling (CFC) reflects (nonlinear) interactions between signals of different frequencies. Evidence from both patient and healthy participant studies suggests that CFC plays an essential role in neuronal computation, interregional interaction, and disease pathophysiology. The present review discusses methodological advances and challenges in the computation of CFC with particular emphasis on potential solutions to spurious coupling, inferring intrinsic rhythms in a targeted frequency band, and causal interferences. We specifically focus on the literature exploring CFC in the context of cognition/memory tasks, sleep, and neurological disorders, such as Alzheimer's disease, epilepsy, and Parkinson's disease. Furthermore, we highlight the implication of CFC in the context and for the optimization of invasive and noninvasive neuromodulation and rehabilitation. Mainly, CFC could support advancing the understanding of the neurophysiology of cognition and motor control, serve as a biomarker for disease symptoms, and leverage the optimization of therapeutic interventions, e.g., closed-loop brain stimulation. Despite the evident advantages of CFC as an investigative and translational tool in neuroscience, further methodological improvements are required to facilitate practical and correct use in cyborg and bionic systems in the field.

Autonomic dysfunction in epilepsy mouse models with implications for SUDEP research

Epilepsy has a high prevalence and can severely impair quality of life and increase the risk of premature death. Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death in drug-resistant epilepsy and most often results from respiratory and cardiac impairments due to brainstem dysfunction. Epileptic activity can spread widely, influencing neuronal activity in regions outside the epileptic network. The brainstem controls cardiorespiratory activity and arousal and reciprocally connects to cortical, diencephalic, and spinal cord areas. Epileptic activity can propagate trans-synaptically or via spreading depression (SD) to alter brainstem functions and cause cardiorespiratory dysfunction. The mechanisms by which seizures propagate to or otherwise impair brainstem function and trigger the cascading effects that cause SUDEP are poorly understood. We review insights from mouse models combined with new techniques to understand the pathophysiology of epilepsy and SUDEP. These techniques include in vivo, ex vivo, invasive and non-invasive methods in anesthetized and awake mice. Optogenetics combined with electrophysiological and optical manipulation and recording methods offer unique opportunities to study neuronal mechanisms under normal conditions, during and after non-fatal seizures, and in SUDEP. These combined approaches can advance our understanding of brainstem pathophysiology associated with seizures and SUDEP and may suggest strategies to prevent SUDEP.

Early cost-utility analysis of genetically guided therapy for patients with drug-resistant epilepsy

OBJECTIVE

Existing gene panels were developed to understand the etiology of epilepsy, and further benefits will arise from an effective pharmacogenomics panel for personalizing therapy and achieving seizure control. Our study assessed the cost-effectiveness of a pharmacogenomics panel for patients with drug-resistant epilepsy, compared with usual care.

METHODS

A cost-utility analysis was employed using a discrete event simulation model. The microsimulation model aggregated the costs and benefits of genetically guided treatment versus usual care for 5000 simulated patients. The 10-year model combined data from various sources including genomic databases on prevalence of variants, population-level pharmaceutical claims on antiseizure medications, published long-term therapy retention rates, patient-level cost data, and systematic reviews. Incremental cost per quality-adjusted life-year (QALY) gained was computed. Deterministic and probabilistic sensitivity analyses were undertaken to address uncertainty in model parameters.

RESULTS

The mean cost of the genetically guided treatment option was AU$98 199 compared with AU$95 386 for usual care. Corresponding mean QALYs were 4.67 compared with 4.28 for genetically guided and usual care strategies, respectively. The incremental cost per QALY gained was AU$7381. In probabilistic sensitivity analyses, the incremental cost per QALY gained was AU$6321 (95% uncertainty interval = AU$3604-AU$9621), with a 100% likelihood of being cost-effective in the Australian health care system. The most influential drivers of the findings were the monthly health care costs associated with reduced seizures, costs when seizures continued, and the quality-of-life estimates under genetically guided and usual care strategies.

SIGNIFICANCE

This early economic evaluation of a pharmacogenomics panel to guide treatment for drug-resistant epilepsy could potentially be cost-effective in the Australian health care system. Clinical trial evidence is necessary to confirm these findings.

Implementation of a Morphological Filter for Removing Spikes from the Epileptic Brain Signals to Improve Identification Ripples

Epilepsy is a very common disease affecting at least 1% of the population, comprising a number of over 50 million people. As many patients suffer from the drug-resistant version, the number of potential treatment methods is very small. However, since not only the treatment of epilepsy, but also its proper diagnosis or observation of brain signals from recordings are important research areas, in this paper, we address this very problem by developing a reliable technique for removing spikes and sharp transients from the baseline of the brain signal using a morphological filter. This allows much more precise identification of the so-called epileptic zone, which can then be resected, which is one of the methods of epilepsy treatment. We used eight patients with 5 KHz data set and depended upon the Staba 2002 algorithm as a reference to detect the ripples. We found that the average sensitivity and false detection rate of our technique are significant, and they are ∼94% and ∼14%, respectively.