Vagal Stimulation Research Articles

An outline of the management and prevention of postoperative ileus: A review.

Postoperative ileus (POI) is a prevalent surgical complication, which results in prolonged hospitalization, patient distress, and substantial economic burden. The literature aims to present a brief outline of interventions for preventing and treating POI post-surgery. Data from 2014 to 2023 were gathered from reputable sources like PubMed, PubMed Central, Google Scholar, Research Gate, and Science Direct. Inclusion criteria focused on studies exploring innovative treatments and prevention strategies for POI, using keywords such as novel POI treatments, non-pharmacological prevention, POI incidence rates, POI management, and risk factors. The findings revealed that integration of preventive measures such as coffee consumption, chewing gum, probiotics, and use of dikenchuto within enhanced recovery programs has significantly reduced both the frequency and duration of POI, without any adverse effects, with minimally invasive surgical approaches showing promise as an additional preventive strategy. While treatment options such as alvimopan, NSAIDs, and acupuncture have demonstrated efficacy, the use of lidocaine has raised concerns due to associated adverse effects. The ongoing exploration of novel therapeutic strategies such as targeting the mast cells, vagal nerve stimulation and tight junction protein, and prokinetic-mediated instigation of the cholinergic anti-inflammatory trail not only holds promise for enhanced treatment but also deepens the understanding of intricate cellular and molecular pathways underlying POI. POI presents a complex challenge in various surgical specialties, necessitating a multifaceted management approach. The integration of preventive and treatment measures within enhanced recovery programs has significantly reduced POI frequency and duration.

Enteric neuropathy and the vagus nerve: Therapeutic implications.

Enteric neuropathies are characterized by abnormalities of gut innervation, which includes the enteric nervous system, inducing severe gut dysmotility among other dysfunctions. Most of the gastrointestinal tract is innervated by the vagus nerve, the efferent branches of which have close interconnections with the enteric nervous system and whose afferents are distributed throughout the different layers of the digestive wall. The vagus nerve is a key element of the autonomic nervous system, involved in the stress response, at the interface of the microbiota-gut-brain axis, has anti-inflammatory and prokinetic properties, modulates intestinal permeability, and has a significant capacity of plasticity and regeneration. Targeting these properties of the vagus nerve, with vagus nerve stimulation (or non-stimulation/ pharmacological methods), could be of interest in the therapeutic management of enteric neuropathies.

Transcutaneous Auricular Vagus Nerve Stimulation Ameliorates Preeclampsia-Induced Apoptosis of Placental Trophoblastic Cells Via Inhibiting the Mitochondrial Unfolded Protein Response.

Preeclampsia is a serious obstetric complication. Currently, there is a lack of effective preventive approaches for this disease. Recent studies have identified transcutaneous auricular vagus nerve stimulation (taVNS) as a potential novel non-pharmaceutical therapeutic modality for preeclampsia. In this study, we investigated whether taVNS inhibits apoptosis of placental trophoblastic cells through ROS-induced UPRmt. Our results showed that taVNS promoted the release of acetylcholine (ACh). ACh decreased the expression of UPRmt by inhibiting the formation of mitochondrial ROS (mtROS), presumably through M3AChR. This reduced the release of pro-apoptotic proteins (cleaved caspase-3, NF-κB-p65, and cytochrome C) and helped preserve the morphological and functional integrity of mitochondria, thus reducing the apoptosis of placental trophoblasts, improving placental function, and relieving preeclampsia. Our study unravels the potential pathophysiological mechanism of preeclampsia. In-depth characterization of the UPRmt is essential for developing more effective therapeutic strategies for preeclampsia targeting mitochondrial function.

Ultrasound-driven piezoelectret-based nanogenerator stimulates vagus nerve for myocardial infarction treatment

Myocardial infarction (MI) stands as the predominant cause of morbidity and mortality within the spectrum of cardiovascular diseases, with an unfavorable long-term prognosis. Vagus nerve stimulation (VNS) emerges as a potential clinically significant intervention for alleviating myocardial remodeling after MI, offering promise as a therapeutic approach. However, challenges persist in addressing the fundamental issues of flexibility, miniaturization, and the long-term use of VNS devices. Here, we devised an implantable ultrasound-driven piezoelectret-based nanogenerator (UPN) as a wireless-powered and battery-free vagus nerve stimulator. The UPN with the features of flexibility and lightweight exhibited a maximum output of 10.68 V and 261 μA (peak to peak) under an ultrasonic probe setup at 700 mW cm−2. In the in vivo efficacy study, VNS therapy resulted in a notable improvement in cardiac function with the treatment of UPN, a 20.42 % enhancement in left ventricular ejection fraction and an 11.76 % increase in fractional shortening on the 28th day were realized. Concomitantly, inflammatory responses, myocardial fibrosis, and sympathetic nerve remodeling witnessed a significant reduction. Particularly noteworthy is the observed therapeutic effect linked to the inhibition of the IL-17 and TNF signaling pathways. In summary, this study introduces a novel strategy for nerve stimulation, offering a potential avenue for treating chronic inflammatory diseases.

Electroencephalogram synchronization measure as a predictive biomarker of Vagus nerve stimulation response in refractory epilepsy: A retrospective study.

There are currently no established biomarkers for predicting the therapeutic effectiveness of Vagus Nerve Stimulation (VNS). Given that neural desynchronization is a pivotal mechanism underlying VNS action, EEG synchronization measures could potentially serve as predictive biomarkers of VNS response. Notably, an increased brain synchronization in delta band has been observed during sleep-potentially due to an activation of thalamocortical circuitry, and interictal epileptiform discharges are more frequently observed during sleep. Therefore, investigation of EEG synchronization metrics during sleep could provide a valuable insight into the excitatory-inhibitory balance in a pro-epileptogenic state, that could be pathological in patients exhibiting a poor response to VNS. A 19-channel-standard EEG system was used to collect data from 38 individuals with Drug-Resistant Epilepsy (DRE) who were candidates for VNS implantation. An EEG synchronization metric-the Weighted Phase Lag Index (wPLI)-was extracted before VNS implantation and compared between sleep and wakefulness, and between responders (R) and non-responders (NR). In the delta band, a higher wPLI was found during wakefulness compared to sleep in NR only. However, in this band, no synchronization difference in any state was found between R and NR. During sleep and within the alpha band, a negative correlation was found between wPLI and the percentage of seizure reduction after VNS implantation. Overall, our results suggest that patients exhibiting a poor VNS efficacy may present a more pathological thalamocortical circuitry before VNS implantation. EEG synchronization measures could provide interesting insights into the prerequisites for responding to VNS, in order to avoid unnecessary implantations in patients showing a poor therapeutic efficacy.

Development of Consensus-Based Best Practice Guidelines for the Peri- and Post-operative Care of Pediatric Patients with Spinal Deformity and Programmable Implanted Devices

Study Design. Modified Delphi consensus study. Objective. To develop consensus-based best practices for the care of pediatric patients who have implanted programmable devices (IPDs) and require spinal deformity surgery. Summary of Background Data. Implanted programmable devices (IPDs) are often present in patients with neuromuscular or syndromic scoliosis who require spine surgery. Guidelines for monitoring and interrogating these devices during the peri-operative period are not available. Methods. A panel was assembled consisting of 25 experts (i.e., spinal deformity surgeons, neurosurgeons, neuro-electrophysiologists, cardiologists, and otolaryngologists). Initial postulates were based on literature review and results from a prior survey. Postulates addressed the following IPDs: vagal nerve stimulators (VNS), programmable ventriculo-peritoneal shunts (VPS), intrathecal baclofen pumps (ITBP), cardiac pacemakers and implantable cardioverter-defibrillators (ICD), deep brain stimulators (DBS), and cochlear implants. Cardiologist and otolaryngologists participants responded only to postulates on cardiac pacemakers or cochlear implants, respectively. Consensus was defined as ≥80% agreement, items that did not reach consensus were revised and included in subsequent rounds. A total of three survey rounds and one virtual meeting were conducted. Results. Consensus was reached on 39 total postulates across six IPD types. Postulates addressed general spine surgery considerations, use of intraoperative monitoring and cautery, use of magnetically-controlled growing rods (MCGRs), and use of an external remote controller to lengthen MCGRs. Across IPD types, consensus for the final postulates ranged from 94.4-100%. Overall, experts agreed that MCGRs can be surgically inserted and lengthened in patients with a variety of IPDs and provided guidance for the use of intraoperative monitoring and cautery, which varied between IPD types. Conclusion. Spinal deformity correction surgery often benefits from the use of intraoperative monitoring, monopolar and bipolar cautery, and MCGRs. Final postulates from this study can inform the peri- and post-operative practices of spinal deformity surgeons who treat patients with both scoliosis and IPDs. Level of Evidence. V- Expert opinion

The Role of KACh Channels in Atrial Fibrillation.

This manuscript explores the intricate role of acetylcholine-activated inward rectifier potassium (KACh) channels in the pathogenesis of atrial fibrillation (AF), a common cardiac arrhythmia. It delves into the molecular and cellular mechanisms that underpin AF, emphasizing the vital function of KACh channels in modulating the atrial action potential and facilitating arrhythmogenic conditions. This study underscores the dual nature of KACh activation and its genetic regulation, revealing that specific variations in potassium channel genes, such as Kir3.4 and K2P3.1, significantly influence the electrophysiological remodeling associated with AF. Furthermore, this manuscript identifies the crucial role of the KACh-mediated current, IKACh, in sustaining arrhythmia through facilitating shorter re-entry circuits and stabilizing the re-entrant circuits, particularly in response to vagal nerve stimulation. Experimental findings from animal models, which could not induce AF in the absence of muscarinic activation, highlight the dependency of AF induction on KACh channel activity. This is complemented by discussions on therapeutic interventions, where KACh channel blockers have shown promise in AF management. Additionally, this study discusses the broader implications of KACh channel behavior, including its ubiquitous presence across different cardiac regions and species, contributing to a comprehensive understanding of AF dynamics. The implications of these findings are profound, suggesting that targeting KACh channels might offer new therapeutic avenues for AF treatment, particularly in cases resistant to conventional approaches. By integrating genetic, cellular, and pharmacological perspectives, this manuscript offers a holistic view of the potential mechanisms and therapeutic targets in AF, making a significant contribution to the field of cardiac arrhythmia research.

Vagus Nerve Stimulation Paired With Upper Extremity Rehabilitation for Chronic Ischemic Stroke: Contribution of Dosage Parameters

Background Vagus nerve stimulation (VNS) combined with rehabilitation is a Food and Drug Administration approved intervention for moderate to severe upper extremity deficits in chronic ischemic stroke patients. Previous studies demonstrated that VNS improves upper extremity motor impairments, using the Fugl Meyer Assessment of Upper Extremity (FMA-UE); however, delineating where these improvements occur, and the role of VNS dosage parameters were not reported. Objective This study explored the relationship between dosing (time over which task repetitions were executed and number of VNS stimulations) and changes within proximal and distal components of the FMA-UE. Methods Participants underwent VNS implantation, with 1 group receiving VNS paired with rehabilitation (Active VNS) and the other group receiving rehabilitation with sham stimulation (Controls). Both groups received 6 weeks of in-clinic therapy followed by a 90-day at-home, self-rehabilitation program. Participants who completed at least 12 of 18 in-clinic sessions were included in the analyses (n = l06). Pearson correlations and analysis of covariance were used to investigate the relationship between dosing and FMA-UE outcome change along with the effect of covariates including baseline severity, time since stroke, age, and paretic side. Results Compared to Controls, active VNS favorably influenced distal function with sustained improvement after the home program. Significant improvements were observed in only distal components (FMdist) at both post day-1 (1.80 points, 95% Cl [0.85, 2.73], P < .001) and post-day 90 (1.62 points, 95% CI [0.45, 2.80], P < .007). Conclusions VNS paired with rehabilitation resulted in significant improvements in wrist and hand impairment compared to Controls, despite similar in-clinic dosing across both groups. NCT03131960

Closed-loop transcutaneous auricular vagus nerve stimulation for the improvement of upper extremity motor function in stroke patients: a study protocol.

Transcutaneous auricular vagus nerve stimulation (taVNS) has garnered attention for stroke rehabilitation, with studies demonstrating its benefits when combined with motor rehabilitative training or delivered before motor training. The necessity of concurrently applying taVNS with motor training for post-stroke motor rehabilitation remains unclear. We aimed to investigate the necessity and advantages of applying the taVNS concurrently with motor training by an electromyography (EMG)-triggered closed-loop system for post-stroke rehabilitation. We propose a double-blinded, randomized clinical trial involving 150 stroke patients assigned to one of three groups: concurrent taVNS, sequential taVNS, or sham control condition. In the concurrent group, taVNS bursts will synchronize with upper extremity motor movements with EMG-triggered closed-loop system during the rehabilitative training, while in the sequential group, a taVNS session will precede the motor rehabilitative training. TaVNS intensity will be set below the pain threshold for both concurrent and sequential conditions and at zero for the control condition. The primary outcome measure is the Fugl-Meyer Assessment of Upper Extremity (FMA-UE). Secondary measures include standard upper limb function assessments, as well as EMG and electrocardiogram (ECG) features. Ethical approval has been granted by the Medical Ethics Committee, affiliated with Zhujiang Hospital of Southern Medical University for Clinical Studies (2023-QX-012-01). This study has been registered on ClinicalTrials (NCT05943431). Signed informed consent will be obtained from all included participants. The findings will be published in peer-reviewed journals and presented at relevant stakeholder conferences and meetings. This study represents a pioneering effort in directly comparing the impact of concurrent taVNS with motor training to that of sequential taVNS with motor training on stroke rehabilitation. Secondly, the incorporation of an EMG-triggered closed-loop taVNS system has enabled the automation and individualization of both taVNS and diverse motor training tasks-a novel approach not explored in previous research. This technological advancement holds promise for delivering more precise and tailored training interventions for stroke patients. However, it is essential to acknowledge a limitation of this study, as it does not delve into examining the neural mechanisms underlying taVNS in the context of post-stroke rehabilitation.

Vagus nerve stimulation for the treatment of treatment-refractory epilepsy

About 40 % of new-onset epilepsy is drug refractory. If epilepsy surgery is not an option or fails, vagal nerve stimulation (VNS) can be considered. VNS efficacy is reported as more than 50 % seizure frequency reduction in 50-56 % of patients. Features in the newer models offer additional treatment optimization possibilities. Side effects include hoarseness, cough, and dyspnoea. Caution is advised for patients with sleep apnoea or lung disease. VNS has specific limitations concerning MRI. This review presents an overview of VNS treatment in Denmark and discusses future challenges.

Expanding the clinical application of OPM-MEG using an effective automatic suppression method for the dental brace metal artifact

Optically pumped magnetometer magnetoencephalography (OPM-MEG) holds significant promise for clinical functional brain imaging due to its superior spatiotemporal resolution. However, effectively suppressing metallic artifacts, particularly from devices such as orthodontic braces and vagal nerve stimulators remains a major challenge, hindering the wider clinical application of wearable OPM-MEG devices.A comprehensive analysis of metal artifact characteristics from time, frequency, and time–frequency perspectives was conducted for the first time using an OPM-MEG device in clinical medicine. This study focused on patients with metal orthodontics, examining the modulation of metal artifacts by breath and head movement, the incomplete regular sub-Gaussian distribution, and the high absolute power ratio in the 0.5–8 Hz band. The existing metal artifact suppression algorithms applied to SQUID-MEG, such as fast independent component analysis (FastICA), information maximization (Infomax), and algorithms for multiple unknown signal extraction (AMUSE), exhibit limited efficacy. Consequently, this study introduced the second-order blind identification (SOBI) algorithm, which utilized multiple time delays for the component separation of OPM-MEG measurement signals. We modified the time delays of the SOBI method to improve its efficacy in separating artifact components, particularly those in the ultralow frequency range. This approach employs the frequency-domain absolute power ratio, root mean square (RMS) value, and mutual information methods to automate the artifact component screening process.The effectiveness of this method was validated through simulation experiments involving four subjects in both resting and evoked experiments. In addition, the proposed method was also validated by the actual OPM-MEG evoked experiments of three subjects. Comparative analyses were conducted against the FastICA, Infomax, and AMUSE algorithms. Evaluation metrics included normalized mean square error, normalized delta band power error, RMS error, and signal-to-noise ratio, demonstrating that the proposed method provides optimal suppression of metal artifacts. This advancement holds promise for enhancing data quality and expanding the clinical applications of OPM-MEG.

Transcutaneous vagal nerve stimulation during lower body negative pressure

BackgroundPara-sympathetic vagal activation has profound influence on heart rate and other cardiovascular parameters. We tested the hypothesis that transcutaneous Vagal Nerve Stimulation (tVNS) through the auricular branch of the vagus nerve would attenuate the normal sympathetic response to central blood volume reduction by lower body negative pressure (LBNP). Method10 healthy volunteers (6 female; age 21 ± 2 years; weight 62 ± 13 kg; height 167 ± 12 cm) were included in this cross-over design trial. After 15 min rest in supine position, subjects underwent three 15-min periods of 30 mmHg LBNP intervention with and without cyclic tVNS stimulation. Continuous cardiovascular parameters (Nexfin) were recorded. ResultsOverall tVNS did not convincingly attenuate sympathetic response to central hypovolemia. Deactivation of the tVNS during LBNP resulted in increased MAP at 2.3 ± 0.5 mmHg (P < 0.001). Comparing the cyclic actual active stimulation periods to periods with pause during tVNS intervention showed a decrease in HR by 72.9 ± 11.2 to 70.2 ± 11.6 bpm (mean ± SD; P < 0.05), and concomitant increases in SV (86.0 ± 12.1 to 87.2 ± 12.6 mL; P < 0.05), MAP (82.9 ± 6.3 to 84.0 ± 6.2 mmHg; P < 0.05) and TPR (1116.0 ± 111.1 to 1153 ± 104.8 dyn*s/cm5; P < 0.05). ConclusiontVNS in 30 s cycles during LBNP can selectively attenuate HR, prompting a compensatory augmented sympathetic response. It would appear the method used in this study at least, has an isolated cardiac inhibitory effect probably mediated by augmented vagal activity on the sinoatrial or atrio-ventricular node, possibly in combination with reduced activity in the sympathetic cardiac nerve.

Effect of vagus nerve stimulation on emergency department utilization in children with drug-resistant epilepsy: a retrospective cohort study.

Epilepsy affects approximately 470,000 children in the United States. The estimated median incidence is 50.4 cases per 100,000 persons per year. There are approximately 3.1 million seizure-related emergency department (ED) visits per year among children. Vagus nerve stimulation (VNS) is a treatment option for drug-resistant epilepsy (DRE). While its primary goal is to decrease seizure burden, VNS may decrease seizure intensity and improve quality of life. The authors assessed whether VNS decreased the number of seizure-related ED visits in a cohort of children with DRE. The authors performed a retrospective chart review of pediatric patients (aged 0-21 years) who underwent implantation of a vagus nerve stimulator between January 2009 and January 2020 at the University of Pittsburgh Medical Center Children's Hospital of Pittsburgh. They used paired t-tests to assess differences in the number of ED visits 2 years before versus 2 years after VNS device implantation. Univariable linear regression analyses were used to test associations of preoperative characteristics with change in the number of ED visits following vagus nerve stimulator insertion. This study included 240 patients. Compared with patients without seizure-related ED visits before VNS, patients with ≥ 1 ED visits were younger in age at first VNS surgery (9.5 vs 10.8 years), had a shorter epilepsy duration before VNS surgery (5.8 vs 7.4 years), had a later year of device implantation (2014 vs 2012), and on average took more antiseizure medications (ASMs; 2.4 vs 2.1). There was no significant difference between the total number of seizure-related ED visits pre- versus post-VNS surgery (1.72 vs 1.59, p = 0.50), and no difference in status epilepticus-related visits (0.59 vs 0.46, p = 0.17). Univariable linear regression analyses revealed a mean change in ED visits of +0.3 for each year prior to 2022 and -0.5 for each additional ASM that patients took before vagus nerve stimulator insertion. This single-institution analysis demonstrated no significant change in the number of seizure-related ED visits within 2 years following VNS device implantation. Earlier VNS surgery was associated with more seizure-related ED visits after device insertion, suggesting that medical management and center experience may play a role in decreasing seizure-related ED visits. A greater number of ASMs was associated with fewer seizure-related ED visits after VNS device insertion, suggesting the role of medical management, patient baseline seizure threshold, and caregiver comfort with at-home seizure management.

Reinforcement learning for closed-loop regulation of cardiovascular system with vagus nerve stimulation: a computational study

Objective. Vagus nerve stimulation (VNS) is being investigated as a potential therapy for cardiovascular diseases including heart failure, cardiac arrhythmia, and hypertension. The lack of a systematic approach for controlling and tuning the VNS parameters poses a significant challenge. Closed-loop VNS strategies combined with artificial intelligence (AI) approaches offer a framework for systematically learning and adapting the optimal stimulation parameters. In this study, we presented an interactive AI framework using reinforcement learning (RL) for automated data-driven design of closed-loop VNS control systems in a computational study. Approach. Multiple simulation environments with a standard application programming interface were developed to facilitate the design and evaluation of the automated data-driven closed-loop VNS control systems. These environments simulate the hemodynamic response to multi-location VNS using biophysics-based computational models of healthy and hypertensive rat cardiovascular systems in resting and exercise states. We designed and implemented the RL-based closed-loop VNS control frameworks in the context of controlling the heart rate and the mean arterial pressure for a set point tracking task. Our experimental design included two approaches; a general policy using deep RL algorithms and a sample-efficient adaptive policy using probabilistic inference for learning and control. Main results. Our simulation results demonstrated the capabilities of the closed-loop RL-based approaches to learn optimal VNS control policies and to adapt to variations in the target set points and the underlying dynamics of the cardiovascular system. Our findings highlighted the trade-off between sample-efficiency and generalizability, providing insights for proper algorithm selection. Finally, we demonstrated that transfer learning improves the sample efficiency of deep RL algorithms allowing the development of more efficient and personalized closed-loop VNS systems. Significance. We demonstrated the capability of RL-based closed-loop VNS systems. Our approach provided a systematic adaptable framework for learning control strategies without requiring prior knowledge about the underlying dynamics.

The therapeutic effect of vagus nerve stimulation on super-refractory nonconvulsive status epilepticus

Super refractory status epilepticus (SRSE) is a condition in which status epilepticus persists despite 48 hours of anesthetic treatment. Nonconvulsive status epilepticus (NCSE) is characterized by seizures lasting more than 30 min on an electroencephalogram, with accompanying changes in behavior or consciousness without convulsions. Prompt treatment of NCSE is crucial, as delayed treatment may lead to additional brain damage and progression to convulsive status epilepticus. Although vagus nerve stimulation (VNS) has been approved as an adjunct treatment for drug-resistant epilepsy, it is rarely used to treat refractory status epilepticus. To the best of our knowledge, only two cases of NCSE treated with VNS have been reported to date, and these patients were successfully treated with VNS for NCSE caused by anti-NMDAR encephalitis. We report the case of a patient with posttraumatic epilepsy who developed super refractory-NCSE after convulsive status epilepticus and was successfully treated with VNS.

Add-On Deep Brain Stimulation versus Continued Vagus Nerve Stimulation for Childhood Epilepsy (ADVANCE): A Partially Randomized Patient Preference Trial.

Outcomes following vagus nerve stimulation (VNS) improve over years after implantation in children with drug-resistant epilepsy. The added value of deep brain stimulation (DBS) instead of continued VNS optimization is unknown. In a prospective, non-blinded, randomized patient preference trial of 18 children (aged 8-17 years) who did not respond to VNS after at least 1 year, add-on DBS resulted in greater seizure reduction compared with an additional year of VNS optimization (51.9% vs. 12.3%, p = 0.047). Add-on DBS also resulted in less bothersome seizures (p = 0.03), but no change in quality of life. DBS may be considered earlier for childhood epilepsy after non-response to VNS. ANN NEUROL 2024;96:405-411.

Characterizing the safety profile of vagus nerve stimulation devices for epilepsy from 21,448 manufacturer and user reports.

This study summarizes medical device reports (MDRs) associated with adverse events for vagus nerve stimulation (VNS) devices indicated for epilepsy as reported by the Manufacturer and User Facility Device Experience (MAUDE) database of the US Food and Drug Administration. The MAUDE database was surveyed for MDRs from November 2013 to September 2022 regarding VNS devices for epilepsy. Event descriptions, device problems, correlated patient consequences, and device models were grouped and analyzed in Python. Based on event description, revision surgeries and other unique events were identified. Revenue from VNS device sales was used to approximate growth in their use over time. A total of 21,448 MDRs met the inclusion criteria. High VNS impedance, the most prevalent device malfunction overall (17.0% of MDRs), was the most common factor for 18 of the 102 encountered patient problems and led to 1001 revision surgeries (3371 total revisions). Included in those 18 device malfunctions were 3 of the top 6 occurring patient problems: seizure recurrence (9.9% associated with high impedance; encompassed focal, absence, and grand mal subtypes), death (1.3%), and generalized pain (7.9%). The next 4 top cited device malfunctions-lead fracture (13.7% of MDRs), operational issue (6.6%), battery problem holding charge (4.2%), and premature end-of-life indicator (2.9%)-differed widely in their percentage of cases that did not impact patients (77.4%, 57.3%, 48.9%, and 92.2%, respectively), highlighting differing malfunction severities. Seizure recurrence, the most prevalent patient impact, was the outcome most associated with 32 of the 68 encountered device problems, including high impedance (12.8%), lead fracture (12.2%), operational issue (18.4%), battery problem holding charge (31.2%), and premature end-of-life indicator (8.9%), which comprised the top 5 occurring device problems. In general, MDRs spanned a diverse range including device age, hardware, software, and surgeon or manufacturer error. Trends were seen over time with declining annual MDRs coupled with a rise in the use of VNS devices as gauged by revenue growth. Shifting device and patient problem profiles were also seen in successive models, reflecting engineering updates. This study characterizes the most common and consequential side effects of VNS devices for epilepsy while clarifying likely causes. In addition, the outcomes of 68 distinct device malfunctions were identified, including many not ubiquitously present in literature, lending critical perspective to clinical practice.

Role of Electroconvulsive Therapy and Transcranial Magnetic Stimulation in Treatment-Resistant Depression

Electroconvulsive therapy (ECT) is one of the oldest known psychiatric treatments in modern times. It preceded modern pharmacotherapy for mood disorders and continues to play a major role in treatment-resistant depression (TRD). Its proven efficacy has been the inspiration behind the continued advancements in the field of neurostimulation. Electroconvulsive therapy, vagus nerve stimulation, and repetitive transcranial magnetic stimulation (rTMS), are currently approved by the US Food and Drug Administration (FDA) as neurostimulation modalities for TRD. Other modalities of neurostimulation such as transcranial direct current stimulation, deep brain stimulation, and magnetic seizure therapy have been studied and used, but are not yet FDA approved. In this article, we will focus on two modalities that are widely used and available to patients: ECT and rTMS. While both treatments are recommended for TRD, either alone or in conjunction with other treatments, they vary widely in their safety profile and treatment protocol, which impacts both patient selection and public perception. [ Psychiatr Ann . 2024;54(6):e164–e169.]

Effects of Transcutaneous Auricular Vagus Nerve Stimulation on Cortical Excitability in Healthy Adults

ObjectiveVagus nerve stimulation (VNS) has recently been reported to exert additional benefits for functional recovery in patients with brain injury. However, the mechanisms underlying these effects have not yet been elucidated. This study examined the effects of transcutaneous auricular VNS (taVNS) on cortical excitability in healthy adults. Materials and MethodsWe recorded subthreshold and suprathreshold single- and paired-pulse motor-evoked potentials (MEPs) in the right-hand muscles of 16 healthy adults by stimulating the left primary motor cortex. Interstimulus intervals were set at 2 milliseconds and 3 milliseconds for intracortical inhibition (ICI), and 10 milliseconds and 15 milliseconds for intracortical facilitation (ICF). taVNS was applied to the cymba conchae of both ears for 30 minutes. The intensity of taVNS was set to a maximum tolerable level of 1.95 mA. MEPs were measured before stimulation, 20 minutes after the beginning of the stimulation, and 10 minutes after the cessation of stimulation. ResultsThe participants’ age was 33.25 ± 7.08 years, and nine of 16 were male. No statistically significant changes were observed in the mean values of the single-pulse MEPs before, during, or after stimulation. Although the ICF showed an increasing trend after stimulation, the changes in ICI and ICF were not significant, primarily because of the substantial interindividual variability. ConclusionsThe effect of taVNS on cortical excitability varied in healthy adults. An increase in ICF was observed after taVNS, although the difference was not statistically significant. Our findings contribute to the understanding of the mechanisms by which taVNS is effective in patients with brain disorders.

What Are the Psychological and Behavioural Outcomes of Vagal Nerve Stimulation and Ketogenic Diet in Children and Young People With Drug-Resistant Epilepsy?

What Are the Psychological and Behavioural Outcomes of Vagal Nerve Stimulation and Ketogenic Diet in Children and Young People With Drug-Resistant Epilepsy?