Vagus nerve stimulation paired with rehabilitation for upper limb motor function after ischaemic stroke (VNS-REHAB): a randomised, blinded, pivotal, device trial

Optimizing non-invasive vagus nerve stimulation for treatment in stroke

Stroke remains a leading cause of long-term disability worldwide. There is an unmet need for neuromodulatory therapies that can mitigate against neurovascular injury and potentially promote neurological recovery. Transcutaneous vagus nerve stimulation has been demonstrated to show potential therapeutic effects in both acute and chronic stroke. However, previously published research has only investigated a narrow range of stimulation settings and indications. In this review, we detail the ongoing studies of transcutaneous vagus nerve stimulation in stroke through systematic searches of registered clinical trials. We summarize the upcoming clinical trials of transcutaneous vagus nerve stimulation in stroke, highlighting their indications, parameter settings, scope, and limitations. We further explore the challenges and barriers associated with the implementation of transcutaneous vagus nerve stimulation in acute stroke and stroke rehabilitation, focusing on critical aspects such as stimulation settings, target groups, biomarkers, and integration with rehabilitation interventions.

Vagus nerve and cancer symptom science

Patients with cancer are often polysymptomatic due to significant disease and treatment-related morbidity. Vagus nerve stimulation (VNS), a type of neuromodulation, affects various physiological processes that are highly relevant to many cancer-related symptoms. It is an emerging therapy that uses the omnipotent nature of the nerve and is known to ameliorate conditions such as depression, epilepsy, gastrointestinal disorders and migraine. Given the evidence base for VNS and its proven utilisation outside of cancer, we suggest research and clinical application of this treatment modality in supportive oncology.

ArmVR: Innovative Design Combining Virtual Reality Technology and Mechanical Equipment in Stroke Rehabilitation Therapy

The rising incidence of stroke has created a significant global public health challenge. The immersive qualities of virtual reality (VR) technology, along with its distinct advantages, make it a promising tool for stroke rehabilitation. To address this challenge, developing VR-based upper limb rehabilitation systems has become a critical research focus. This study developed and evaluated an innovative ArmVR system that combines VR technology with rehabilitation hardware to improve recovery outcomes for stroke patients. Through comprehensive assessments, including neurofeedback, pressure feedback, and subjective feedback, the results suggest that VR technology has the potential to positively support the recovery of cognitive and motor functions. Different VR environments affect rehabilitation outcomes: forest scenarios aid emotional relaxation, while city scenarios better activate motor centers in stroke patients. The study also identified variations in responses among different user groups. Normal users showed significant changes in cognitive function, whereas stroke patients primarily experienced motor function recovery. These findings suggest that VR-integrated rehabilitation systems possess great potential, and personalized design can further enhance recovery outcomes, meet diverse patient needs, and ultimately improve quality of life.

3-D Printable Living Hydrogels as Portable Bio-energy Devices

Harnessing engineered living materials for energy application represents a promising avenue to sustainable energy conversion and storage, with bio-batteries emerging as a pivotal direction for sustainable power supply. Whereas, the realization of miniaturized and portable bio-battery orchestrating off-the-shelf devices remains a significant challenge. Here, this work reports the development of a miniaturized and portable bio-battery using living hydrogels containing conductive biofilms encapsulated in an alginate matrix for nerve stimulation. These hydrogels, which can be 3-D printed into customized geometries, retained biologically active characteristics, including electroactivity that facilitates electron generation and the reduction of graphene oxide. By fabricating the living hydrogel into a standard 2032 battery shell with a diameter of 20 mm, this work successfully creates a miniaturized and portable bio-battery with self-charging performance. The device demonstrates remarkable electrochemical performance with a coulombic efficiency of 99.5% and maintains high cell viability exceeding 90% after operation. Notably, the electricity generated by the bio-battery can be harnessed for nerve stimulation to enable precise control over bioelectrical stimulation and physiological blood pressure signals. This study paves the way for the development of novel, compact, and portable bio-energy devices with immense potential for future advancements in sustainable energy technologies.

High-Dose, High-Intensity Stroke Rehabilitation: Why Aren't We Giving It?

Current doses and intensities of post-stroke rehabilitation therapy provided as “usual care” are paltry compared to the magnitudes needed to drive large behaviorally-relevant reductions in neurologic impairments. There is convergent evidence indicating that high dose, high intensity rehabilitation is effective for improving outcomes after stroke with large effect sizes compared to usual care. Here we highlight some of this evidence (focusing on studies of upper extremity motor rehabilitation) and then ask the simple question— why are we not delivering high doses and intensities of rehabilitation in clinical practice? We contend that reasons for lack of implementation of high dose, high intensity rehabilitation have to do with questionable conceptual, ideological, and economic assumptions. In addition, there are practical challenges, which we argue can be overcome with technology. Current practice (we refer primarily to the context of US healthcare) in stroke rehabilitation is itself built on very little evidence, indeed considerably less than the cumulative evidence indicating that high dose, high intensity rehabilitation would be more effective. Our hope is that this Perspective will help persuade multiple stake holders (neurologists, physiatrists, therapists, researchers, patients, policy makers, and insurance companies) to advocate for higher doses and intensities of rehabilitation. There is certainly more research to be done on new ways to deliver high-dose, high-intensity neurorehabilitation, as well as zeroing in on its best timing and dosing, and how to best combine it with drugs and physiological stimulation. In the meantime, our view is that a large body of convergent evidence already justifies seeking to incorporate higher doses and intensities of therapy into current clinical practice as the new standard of care.

MGH Laboratory for Translational Neurorecovery: @LTNeurorecovery (X), @ltneuro (Instagram)

MGH Center for Neurotechnology and Neurorecovery: @MGH_CNTR (X)

Current and future clinical trials for the use of neuromodulation in the treatment of stroke: A review of the clinical Trials.gov database

Neuromodulation is a rapidly growing field in neurosurgery and has shown promise in the treatment of stroke. The aim of this study is to review current clinical trials assessing the role of neuromodulation in the treatment of stroke and post-stroke impairments. Clinical trials were found using the search terms "stroke" and "stimulation." A total of 996 clinical trials were included in this study with 386 excluded before analysis. Overall, the number of published clinical trials significantly increased over time (p < 0.001; r = 0.927). Of these, 452 (63.7 %) clinical trials were completed, 242 (34.1 %) were in the recruitment stage, and 16 (2.3 %) in the active and not recruiting stage. Of these trials, 77 were completed with published results. By treatment modality, 35 of the published trials evaluated the use of tDCS or TMS. An additional 28 of the published trials evaluated neuromuscular stimulation. Finally, three evaluated VNS, two evaluated medication treatment and nine were found evaluating a wide variety of other modalities. Other interventions included electrical stimulation of various peripheral nerves or muscles, vagal nerve stimulation, deep brain stimulation, and thermoneuromodulation. A majority of trials studied the effects of stroke on motor function (47). The remaining studies assessed outcomes including aphasia (10), pain (6), coordination and gait (5), imaging outcomes (5), swallowing (2), sensation (1) and cognition (1). There has been strong interest in studying the effect of neuromodulation on recovery after stroke with majority of the current clinical trials studying the use of tDCS or TMS to improve motor function.

Safety and efficacy of transcranial direct current stimulation in addition to constraint-induced movement therapy for post-stroke motor recovery (TRANSPORT2): a phase 2, multicentre, randomised, sham-controlled triple-blind trial

BACKGROUND

Motor impairments contribute substantially to long-term disability following stroke. Studies of transcranial direct current stimulation (tDCS), combined with various rehabilitation therapies, have shown promising results in reducing motor impairment. We aimed to evaluate the safety and efficacy of three doses of tDCS in combination with modified constraint-induced movement therapy (mCIMT) in people who have had their first ischaemic stroke in the preceding 1-6 months.

METHODS

We conducted a phase 2, multicentre, randomised, triple-blind, sham-controlled study with a blinded centrally scored primary outcome. The trial was conducted at 15 medical centres in the USA. Eligible participants were enrolled between 1 month and 6 months after their first ischaemic stroke. Inclusion criteria required participants to have a persistent motor deficit, defined as a Fugl-Meyer Upper-Extremity (FM-UE) score of 54 or lower (out of 66), and two consecutive baseline visits (separated by 7-14 days) with an absolute difference of 2 or fewer points on the FM-UE scale. Participants were randomly assigned to treatment groups by an adaptive randomisation algorithm hosted on the TRANSPORT2 WebDCU study website. Participants received either sham, 2 mA, or 4 mA of bi-hemispheric tDCS for the first 30 min and mCIMT with 120 min of active therapy time per session, administered over ten sessions during a 2-week period. The primary endpoint was the change in FM-UE score from baseline to day 15, which was analysed in all participants who have data both at baseline and post-baseline (modified intention-to-treat group). Safety outcomes were analysed in all participants. TRANSPORT2 is registered at clinicaltrials.gov (NCT03826030) and its status is completed.

FINDINGS

129 participants were recruited between Sept 9, 2019, and June 14, 2024, and 43 participants were randomly assigned to each group. 54 (42%) of 129 participants were female, and 69 (53%) were White. Two participants in the sham plus mCIMT group withdrew consent before the day 15 assessment and were excluded from the primary analysis. The median baseline FM-UE score was 39·0 (IQR 30·0-46·0) in the sham plus mCIMT group, 39·0 (27·0-48·0) in the 2 mA plus mCIMT group, and 40·0 (27·0-48·0) in the 4 mA plus mCIMT group. For the primary outcome, the adjusted mean change from baseline to day 15 in FM-UE was 4·91 (3·00-6·82) for sham plus mCIMT, 3·87 (2·00-5·74) for 2 mA plus mCIMT, and 5·53 (3·64-7·42) for 4 mA plus mCIMT (p=0·39). No clinically important adverse events were observed in any group and no deaths were reported.

INTERPRETATION

tDCS at doses of 2 mA or 4 mA, in addition to mCIMT, did not lead to further reduction in motor impairment in patients 1-6 months after stroke, but it was safe, well tolerated, and feasible for clinical practice. tDCS at higher doses (ie, >4 mA) might be a consideration for future trials in addition to balancing known covariates affecting stroke recovery during the group allocation.

FUNDING

National Institute of Neurological Disorders and Stroke.

Closed-loop rehabilitation of upper-limb dyskinesia after stroke: from natural motion to neuronal microfluidics

This review proposes an innovative closed-loop rehabilitation strategy that integrates multiple subdomains of stroke science to address the global challenge of upper-limb dyskinesia post-stroke. Despite advancements in neural remodeling and rehabilitation research, the compartmentalization of subdomains has limited the effectiveness of current rehabilitation strategies. Our approach unites key areas-including the post-stroke brain, upper-limb rehabilitation robotics, motion sensing, metrics, neural microfluidics, and neuroelectronics-into a cohesive framework designed to enhance upper-limb motion rehabilitation outcomes. By leveraging cutting-edge technologies such as lightweight rehabilitation robotics, advanced motion sensing, and neural microfluidic models, this strategy enables real-time monitoring, adaptive interventions, and personalized rehabilitation plans. Furthermore, we explore the potential of closed-loop systems to drive neural plasticity and functional recovery, offering a transformative perspective on stroke rehabilitation. Finally, we discuss future directions, emphasizing the integration of emerging technologies and interdisciplinary collaboration to advance the field. This review highlights the promise of closed-loop strategies in achieving unprecedented integration of subdomains and improving post-stroke upper-limb rehabilitation outcomes.

Vagus nerve stimulation as a predictive coding modulator that enhances feedforward over feedback transmission

Vagus nerve stimulation (VNS) has emerged as a promising therapeutic intervention across various neurological and psychiatric conditions, including epilepsy, depression, and stroke rehabilitation; however, its mechanisms of action on neural circuits remain incompletely understood. Here, we present a novel theoretical framework based on predictive coding that conceptualizes VNS effects through differential modulation of feedforward and feedback neural circuits. Based on recent evidence, we propose that VNS shifts the balance between feedforward and feedback processing through multiple neuromodulatory systems, resulting in enhanced feedforward signal transmission. This framework integrates anatomical pathways, receptor distributions, and physiological responses to explain the influence of the VNS on neural dynamics across different spatial and temporal scales. Vagus nerve stimulation may facilitate neural plasticity and adaptive behavior through acetylcholine and noradrenaline (norepinephrine), which differentially modulate feedforward and feedback signaling. This mechanistic understanding serves as a basis for interpreting the cognitive and therapeutic outcomes across different clinical conditions. Our perspective provides a unified theoretical framework for understanding circuit-specific VNS effects and suggests new directions for investigating their therapeutic mechanisms.

Research hotspots and frontiers of neuromodulation technology in the last decade: a visualization analysis based on the Web of Science database

Background

Since the 1990s, neuromodulation technology has experienced rapid advancements, providing new therapeutic approaches for clinical rehabilitation in neurological disorders. The objective of this study is to utilize CiteSpace and VOSviewer to investigate the current research status, key topics, and future trends in the field of neuromodulation technology over the past decade.

Methods

Relevant literature in the field of neuromodulation technology published in Web of Science database from January 1, 2014 to June 18, 2024 were retrieved, and imported into CiteSpace and VOSviewer for visualization. VOSviewer was used for counties, institutions, authors and keywords analyses. CiteSpace was used for presentation visualization analysis of co-cited references, keywords clusters and bursts.

Results

This study encompasses a total of 1,348 relevant publications, with the number of publications showing an increasing trend year by year. The most significant growth was observed between 2020 and 2021. The United States, China and the United Kingdom are the three leading countries with high output in this regard. The top three institutions in terms of the publication volume are Harvard Medical School, the University of Toronto and Stanford University. Keyword co-occurrence and cluster analysis identified that deep brain stimulation, transcranial magnetic stimulation, transcranial direct current stimulation, and focused ultrasound stimulation are the most widely used central nerve stimulation techniques in neuromodulation. The treatment of intractable chronic pain also emerged as a key focus within neuromodulation techniques. The recent keywords bursts included terms such as recovery, movement, nucleus, modeling and plasticity, suggesting that the future research trend will be centered on these areas.

Conclusion

In conclusion, neuromodulation technology is garnering increasing attention from researchers and is currently widely used in brain diseases. Future research is expected to delve deeper, particularly into exploring deep brain structure stimulation targets and restoring motor function based on neuroplasticity theory.

Dopaminergic Pathways in Neuroplasticity After Stroke and Vagus Nerve Stimulation

Stroke remains a significant cause of disability worldwide. In addition to multidisciplinary rehabilitation approaches, various forms of technology, including vagus nerve stimulation, have emerged to facilitate neuroplasticity and, thereby, improve functional status after stroke. Vagus nerve stimulation was recently approved by the Food and Drug Administration, but questions remain regarding its mechanism of action. Here, a potential role for dopaminergic signaling is considered. This review first examines evidence that dopamine is important to neuroplasticity after stroke. Next, 2 different dopaminergic pathways are considered potential mechanisms underlying vagus nerve stimulation-related benefits after stroke, direct modulation of brain dopaminergic pathways, and engagement of systemic dopaminergic pathways such as those found in the gut-brain axis. A contribution of dopamine signaling to vagus nerve stimulation efficacy could have therapeutic implications that extend to a precision medicine approach to stroke rehabilitation.

'Transauricular vagus nerve stimulation' for prevention of postoperative delirium in elderly patients undergoing major surgery: a study protocol for a multicentre, participant-blinded and assessor-blinded, randomised, controlled trial

INTRODUCTION

Postoperative delirium (POD) is a frequent complication in elderly patients undergoing major surgery. Research has shown that neuroinflammation, postoperative pain and autonomic nervous system dysfunction play significant roles in its onset. Vagus nerve stimulation (VNS) has the potential to reduce inflammation, ease postoperative pain and aid in recovery by enhancing acetylcholine release and activating the cholinergic anti-inflammatory pathway. This study aims to assess the effectiveness and safety of transauricular VNS (ta-VNS) in preventing POD in elderly patients undergoing major surgery.

METHODS AND ANALYSIS

This multicentre, participant-blinded and assessor-blinded, randomised, parallel-group controlled trial will compare the incidence of POD in elderly patients undergoing major surgery who receive ta-VNS versus sham stimulation. A total of 300 eligible patients will be randomly assigned in a 1:1 ratio to either the active or sham stimulation group. The active stimulation group will receive electrical stimulation to the left cymba conchae at a frequency of 30 Hz and a pulse width of 250 µs, with a 30 s on/30 s off cycle. The intensity will start at 0.4V and be increased in 0.4V increments until a tingling sensation is felt, then adjusted to the highest tolerable level without pain. After obtaining informed consent and randomisation, the initial intervention will begin in the preoperative area and continue throughout the surgery. For the four postoperative days, the intervention will be administered twice daily in 2-hour sessions each morning and afternoon. The sham group will follow the same procedure, with electrodes placed on the left cymba conchae. After adjusting the stimulation intensity, the device will be switched off. The primary outcome is the incidence of POD from postoperative day 0 to day 7 or discharge. Secondary outcomes include the severity of POD, quality of recovery, sleep quality and adverse events.

ETHICS AND DISSEMINATION

The protocol was approved by Sir Run Run Shaw Hospital Affiliated to Zhejiang University School of Medicine on 9 January 2024 (Approval number: 20240014), and the trial was registered on the Chinese Clinical Trial Registry on 21 February 2024, prior to recruitment. The study will be performed according to the guidelines of the Declaration of Helsinki. Written informed consent will be obtained from all participants. The results will be submitted for publication in a refereed journal.

TRIAL REGISTRATION NUMBER

ChiCTR2400081078.

Two decades of vagus nerve stimulation for stroke: a bibliometric analysis

Background

Stroke is a major global health concern, imposing significant medical and social burdens. Vagus nerve stimulation (VNS), an emerging neuromodulation technology, has shown potential in the treatment of stroke. This bibliometric analysis aims to explore the knowledge structure and research trends in the field of VNS for stroke from 2004 to 2024.

Methods

Publications were retrieved from the Web of Science Core Collection. CiteSpace and VOSviewer were used to conduct bibliometric analyses, including author productivity, institutional contributions, and emerging research themes etc.

Results

A total of 191 eligible publications were analysed. Kilgard, M. P., and Hays, S. A. were the most prolific authors, each contributing 26 publications. The USA (96 publications), China (69 publications), and Scotland (17 publications) were the most prolific countries. The University of Texas at Dallas (33 publications) was the most prolific institution, followed by Chongqing Medical University (19 publications) and the University of Glasgow (15 publications). Future research is expected to focus on: (1) neurophysiological mechanisms of VNS in stroke recovery; (2) synergistic effects of VNS with other rehabilitation therapies; (3) comparative efficacy of non-invasive transauricular VNS versus invasive VNS; (4) safety and effectiveness of VNS for post-stroke functional impairments beyond motor rehabilitation; and (5) optimisation of VNS parameters for stroke treatment.

Conclusion

The field of VNS for stroke has experienced steady growth over the past two decades. This bibliometric analysis provides valuable insights to guide future research, clinical applications, and policy developments.

Vagus nerve stimulation rescues impaired fear extinction and social interaction in a rat model of autism spectrum disorder

Clinical diagnosis of anxiety disorders is highly prevalent in autism spectrum disorders (ASD). Available treatments for anxiety offer limited efficacy in the ASD population. Vagus nerve stimulation (VNS) has an anxiolytic effect in rats and, when coupled with fear extinction training, VNS enhances extinction of fear in healthy rats. The valproic acid (VPA)-induced rat model of autism shows impaired extinction of fear and deficits in social interaction. This study was designed to test the potential of VNS to rescue extinction learning and influence social behaviors in VPA-exposed rats. After VNS or sham surgery, VPA-exposed rats or controls were subjected to auditory fear conditioning followed by extinction training paired with VNS or sham stimulation. Another cohort was exposed to a social interaction task paired with VNS or sham stimulation. Time spent freezing was not significantly reduced during retention testing 24 h after extinction training in VPA-exposed rats given sham stimulation (p = .26), but freezing levels were significantly lower during the retention test in saline control and in VPA-VNS rats (p < .05), indicating that VNS reverses extinction deficits in VPA-exposed rats. In addition, social interaction scores were significantly lower in VPA-sham rats (p < .0005), but VPA-VNS rats were not significantly different from saline controls (p = .19), suggesting that VNS also alleviates social interaction deficits in VPA-exposed rats. VNS is approved for use in humans for treatment of epilepsy, depression, and stroke. These findings suggest that VNS may be a useful tool for overcoming treatment resistant anxiety in ASD.

Association that Neuroimaging and Clinical Measures Have with Change in Arm Impairment in a Phase 3 Stroke Recovery Trial

OBJECTIVE

Vagus nerve stimulation (VNS) paired with rehabilitation therapy improved motor status compared to rehabilitation alone in the phase III VNS-REHAB stroke trial, but treatment response was variable and not associated with any clinical measures acquired at baseline, such as age or side of paresis. We hypothesized that neuroimaging measures would be associated with treatment-related gains, examining performance of regional injury measures versus global brain health measures in parallel with clinical measures.

METHODS

Baseline magnetic resonance imaging (MRI) scans in the VNS-REHAB trial were used to derive regional injury measures (extent of injury to corticospinal tract, the primary regional measure; plus extent of injury to precentral gyrus and postcentral gyrus; lesion volume; and lesion topography) and global brain health measures (degree of white matter hyperintensities, the primary global brain measure; plus volumes of cerebrospinal fluid, cortical gray matter, white matter, each thalamus, and total brain). Eight clinical measures assessed at baseline were also evaluated (treatment group, age, race, gender, paretic side, pre-stroke dominant hand, time since stroke, and baseline Fugl-Meyer upper extremity score). Bivariate analyses compared each measure with the primary trial end point (change in Fugl-Meyer upper extremity score from baseline to end of 6 weeks of treatment) across all subjects, with secondary analyses examining trial groups separately.

RESULTS

MRIs were available from 80 patients (age = 59.8 ± 9.5 years, 29 women). Across all patients, less white matter hyperintensities (r = -0.25, p = 0.028) at baseline was associated with larger Fugl-Meyer score change. In the VNS group, less white matter hyperintensities (r = -0.37, p = 0.018) and larger ipsilesional thalamus volume (r = 0.33, p = 0.046) were each associated with larger Fugl-Meyer score change. Analysis of covariance (ANCOVA) analyses tested the interaction that each baseline measure had with treatment group and found that the model examining white matter hyperintensities had a significant interaction term, indicating 2.3 less change in Fugl-Meyer Upper Extremity (FM-UE) points in the VNS group relative to the control group for each point increase in modified Fazekas scale.

INTERPRETATION

Neuroimaging measures are associated with extent of gains on the primary endpoint of a phase III stroke recovery trial. Among the neuroimaging measures examined, a measure of global brain health (extent of white matter hyperintensities) was better at explaining the change in arm impairment as compared with measures of regional injury; this was true when examining all study subjects as well as only those in the VNS group and is consistent with the global mechanism of action that VNS has throughout the cerebrum. Future studies can evaluate additional measures that further predict response to VNS therapy. The current findings suggest that individual patient neuroimaging results may be useful for a personalized medicine approach to stroke recovery therapeutics. ANN NEUROL 2025;97:709-719.

Vagus Nerve Stimulation in Stroke Management: Brief Review of Evolution and Present Applications Paired with Rehabilitation

Cerebrovascular accident (CVA) or stroke is a devastating neurological condition with dismal prognosis associated with recurrent episodes that further damage the neuronal networks, thus disabling neuronal plasticity. Vagus nerve stimulation (VNS) has been used in clinical practice to treat epilepsy for several decades and is well accepted as a safe procedure devoid of serious adverse events. Bailey and Bremer demonstrated that VNS has the capabilities to stimulate neuronal pathways that enhance the recovery of damaged cerebral function. Further studies have strengthened these observations, while technology has improved the tolerability of implants, resulting in VNS applications for epilepsy. Several animal models on neural plasticity have improved our understanding of VNS and its ability to provide neuromodulation to improve recovery in stroke patients. The closed-loop stimulation of the vagus nerve with individualized stimulation parameters combined with physical therapy appears to be an attractive option today. VNS is also being tested as a noninvasive trans-cutaneous modality to further improve patient acceptance and tolerability. However, the implantation of VNS is yielding desirable outcomes and appears to be a more reliable treatment for stroke rehabilitation in clinical trials.

TRanscutaneous lImb reCovEry Post-Stroke (TRICEPS): study protocol for a randomised, controlled, multiarm, multistage adaptive design trial

INTRODUCTION

Arm weakness after stroke is one of the leading causes of adult-onset disability. Invasive vagus nerve stimulation (VNS) paired with rehabilitation has been shown to improve arm recovery in chronic stroke. Small studies of non-invasive or transcutaneous VNS (tVNS) suggest it is safe and tolerable. However, it is not known whether tVNS paired with rehabilitation is effective in promoting arm recovery in chronic stroke and what the mechanisms of action are.

METHODS AND ANALYSIS

TRICEPS is a UK multicentre, double-blinded, superiority, parallel-group, three-arm two-stage with an option to select promising arm(s) at 50% accrual, individually randomised, sham-controlled trial. Up to 243 participants will be randomised (1:1:1) using minimisation via a restricted, web-based centralised system. tVNS will be delivered by a movement-activated tVNS system (TVNS Technologies), which delivers stimulation during repetitive task practice. Rehabilitation will consist of repetitive task training for 1 hour a day, 5 days per week for 12 weeks. Participants will be adults with anterior circulation ischaemic stroke between 6 months and 10 years prior with moderate-severe arm weakness. The primary outcome measure will be the change in Upper Limb Fugl-Meyer total motor score at 91 days after the start of treatment. Secondary outcome measures include the Wolf Motor Function Test, the Modified Ashworth Scale to assess spasticity in the affected arm and the Stroke-Specific Quality of Life Scale. A mechanistic substudy including 40 participants will explore the mechanisms of active versus sham tVNS using multimodal MRI and serum inflammatory cytokine levels. Participant recruitment started on 30 November 2023.

ETHICS AND DISSEMINATION

The study has received ethical approval from the Cambridge Central Research Ethics Committee (REC reference: 22/NI/0134). Dissemination of results will be via publications in scientific journals, meetings, written reports and articles in stakeholder publications.

TRIAL REGISTRATION NUMBER

ISRCTN20221867.

Accelerated Transcutaneous Auricular Vagus Nerve Stimulation for Inpatient Depression and Anxiety: The iWAVE Open Label Pilot Trial

INTRODUCTION

Brain stimulation is not a common inpatient psychiatric treatment; however, there are an increasing number of neuromodulation treatments approved for psychiatric indications. Noninvasive techniques, such as transcutaneous auricular vagus nerve stimulation (taVNS), are promising and should be investigated in this novel setting. This study evaluates the safety and feasibility of taVNS on the inpatient psychiatric unit and preliminarily explores efficacy for comorbid depression and anxiety.

MATERIALS AND METHODS

Ten adult patients (five women, mean age ± SD, 35.60 ± 19.14 years) admitted to the inpatient psychiatric unit with comorbid depression and anxiety participated in this open-label safety and feasibility trial. Patients were randomized to receive one of two taVNS dosing approaches: 1) three taVNS sessions on three consecutive days (nine sessions total) (n = 5) or 2) nine taVNS sessions in one day (n = 5). Each day, we assessed depression, using the Patient Health Questionnaire (PHQ-9) and Beck Depression Inventory (BDI), and anxiety, using the Generalized Anxiety Disorder-7 (GAD-7) and Beck Anxiety Inventory (BAI).

RESULTS

Both taVNS dosing approaches were safe and feasible in this novel setting. There were no serious adverse events, and we observed a low rate of minor adverse effects, which was similar across treatment conditions. Regardless of condition, stimulation significantly reduced GAD-7 (mean reduction ± SD, -5.90 to 6.87, p < 0.05), BAI (-9.40 ± 10.52, p < 0.05), PHQ-9 (-6.00 ± 7.57, p < 0.05), and BDI (-11.00 ± 11.59, p < 0.05) final scores compared with baseline. There was not a significant difference in clinical response between treatment conditions.

DISCUSSION

In this open label study, taVNS significantly decreased depression and anxiety symptoms in patients admitted to the inpatient unit. The small sample size in this trial limited our ability to characterize patient characteristics that may drive response. However, our results suggest taVNS may be an effective adjunct to inpatient psychiatric treatment and should continue to be studied in this setting.

CLINICAL TRIAL REGISTRATION

The Clinicaltrials.gov registration number for the study is NCT05791383.

Analysis of the effect of combined rehabilitation training and transcutaneous vagus nerve electrical stimulation on promoting central nervous system remodeling in stroke patients

OBJECTIVE

To explore the effect of combined rehabilitation training and transcutaneous vagus nerve electrical stimulation (t-VNS) on promoting central nervous system remodeling and neurological function recovery in stroke patients.

METHODS

A total of 124 S patients admitted to our hospital from January to December 2023 were included in this study. The therapeutic effects were evaluated using the Modified Barthel Index (MBI) and the simplified Fugl-Meyer Assessment Scale (sFMA) to measure patients' activities of daily living and motor function recovery. Additionally, neurophysiological assessments, including electromyography (EMG) and motor evoked potentials (MEPs), were conducted to evaluate changes in neuromuscular and central nervous system function. Changes in neural activity in the frontal lobe and motor cortex were assessed through transcutaneous vagus nerve stimulation and electroencephalography. Moreover, all adverse events were recorded.

RESULTS

After treatment, patients in the t-VNS combined with rehabilitation training group showed significant improvements in sFMA and MBI scores compared to the pure rehabilitation training group (P < 0.05). In terms of neurophysiology, patients in the combined treatment group exhibited significant increases in electromyographic activity and MEPs (P < 0.05). EEG results indicated enhanced neuroplasticity of the frontal lobe and motor cortex with t-VNS treatment. The incidence of skin stimulation and ear pain in the combined treatment group was significantly higher than that in the pure rehabilitation training group.

CONCLUSION

Combined rehabilitation training and transcutaneous vagus nerve electrical stimulation have significant effects on neurological function recovery and central nervous system remodeling in stroke patients, effectively improving patients' motor function and activities of daily living.

Vagus nerve stimulation therapy for treatment-resistant PTSD

BACKGROUND

Posttraumatic stress disorder (PTSD) is common and debilitating, and many individuals do not respond to existing therapies. We developed a fundamentally novel neuromodulation-based therapy for treatment-resistant PTSD. This approach is premised on coupling prolonged exposure therapy, a first-line evidence-based cognitive behavioral therapy that directs changes within fear networks, with concurrent delivery of short bursts of vagus nerve stimulation (VNS), which enhance synaptic plasticity.

METHODS

We performed a first-in-human prospective open-label early feasibility study (EFS) using a next-generation miniaturized system to deliver VNS therapy in nine individuals with moderate to severe treatment-resistant PTSD. All individuals received a standard 12-session course of prolonged exposure therapy combined with VNS. Assessments were performed before, 1 week after, and 1, 3, and 6 months after the completion of therapy.

CLINICALTRIALS

gov registration: NCT04064762.

RESULTS

VNS therapy resulted in significant, clinically-meaningful improvements in multiple metrics of PTSD symptoms and severity compared to baseline (CAPS-5, PCL-5, and HADS all p < 0.001 after therapy). These benefits persisted at 6 months after the cessation of therapy, suggesting lasting improvements. All participants showed loss of PTSD diagnosis after completing treatment. No serious or unexpected device-related adverse events were observed.

CONCLUSIONS

These findings provide a demonstration of the safety and feasibility of VNS therapy for PTSD and highlight the potential of this approach. Collectively, these support the validation of VNS therapy for PTSD in a rigorous randomized controlled trial.

Overcoming failure: improving acceptance and success of implanted neural interfaces

Implanted neural interfaces are electronic devices that stimulate or record from neurons with the purpose of improving the quality of life of people who suffer from neural injury or disease. Devices have been designed to interact with neurons throughout the body to treat a growing variety of conditions. The development and use of implanted neural interfaces is increasing steadily and has shown great success, with implants lasting for years to decades and improving the health and quality of life of many patient populations. Despite these successes, implanted neural interfaces face a multitude of challenges to remain effective for the lifetime of their users. The devices are comprised of several electronic and mechanical components that each may be susceptible to failure. Furthermore, implanted neural interfaces, like any foreign body, will evoke an immune response. The immune response will differ for implants in the central nervous system and peripheral nervous system, as well as over time, ultimately resulting in encapsulation of the device. This review describes the challenges faced by developers of neural interface systems, particularly devices already in use in humans. The mechanical and technological failure modes of each component of an implant system is described. The acute and chronic reactions to devices in the peripheral and central nervous system and how they affect system performance are depicted. Further, physical challenges such as micro and macro movements are reviewed. The clinical implications of device failures are summarized and a guide for determining the severity of complication was developed and provided. Common methods to diagnose and examine mechanical, technological, and biological failure modes at various stages of development and testing are outlined, with an emphasis on chronic in vivo characterization of implant systems. Finally, this review concludes with an overview of some of the innovative solutions developed to reduce or resolve the challenges faced by implanted neural interface systems.

The Role of Sensory Impairments on Recovery and Rehabilitation After Stroke

PURPOSE OF REVIEW

The current review aims to address critical gaps in the field of stroke rehabilitation related to sensory impairment. Here, we examine the role and importance of sensation throughout recovery of neural injury, potential clinical and experimental approaches for improving sensory function, and mechanism-based theories that may facilitate the design of sensory-based approaches for the rehabilitation of somatosensation.

RECENT FINDINGS

Recently, the field of neurorehabilitation has shifted to using more quantitative and sensitive measures to more accurately capture sensory function in stroke and other neurological populations. These approaches have laid the groundwork for understanding how sensory impairments impact overall function after stroke. However, there is less consensus on which interventions are effective for remediating sensory function, with approaches that vary from clinical re-training, robotics, and sensory stimulation interventions. Current evidence has found that sensory and motor systems are interdependent, but commonly have independent recovery trajectories after stroke. Therefore, it is imperative to assess somatosensory function in order to guide rehabilitation outcomes and trajectory. Overall, considerable work in the field still remains, as there is limited evidence for purported mechanisms of sensory recovery, promising early-stage work that focuses on sensory training, and a considerable evidence-practice gap related to clinical sensory rehabilitation.

Advancements in the investigation of gut microbiota-based strategies for stroke prevention and treatment

Stroke represents a predominant cause of mortality and disability on a global scale, impacting millions annually and exerting a considerable strain on healthcare systems. The incidence of stroke exhibits regional variability, with ischemic stroke accounting for the majority of occurrences. Post-stroke complications, such as cognitive impairment, motor dysfunction, and recurrent stroke, profoundly affect patients' quality of life. Recent advancements have elucidated the microbiota-gut-brain axis (MGBA), underscoring the complex interplay between gut health and brain function. Dysbiosis, characterized by an imbalance in gut microbiota, is significantly linked to an elevated risk of stroke and unfavorable outcomes. The MGBA plays a crucial role in modulating immune function, neurotransmitter levels, and metabolic byproducts, which may intensify neuroinflammation and impair cerebral health. This review elucidates the role of MGBA in stroke pathophysiology and explores potential gut-targeted therapeutic strategies to reduce stroke risk and promote recovery, including probiotics, prebiotics, pharmacological interventions, and dietary modifications. However, the current prevention and treatment strategies based on intestinal flora still face many problems, such as the large difference of individual intestinal flora, the stability of efficacy, and the long-term safety need to be considered. Further research needs to be strengthened to promote its better application in clinical practice.

Clinical state and future directions of stem cell therapy in stroke rehabilitation

Despite substantial advances in the acute management of stroke, it remains a leading cause of adult disability and mortality worldwide. Currently, the reperfusion modalities thrombolysis and thrombectomy benefit only a fraction of patients in the hyperacute phase of ischemic stroke. Thus, with the exception of vagal nerve stimulation combined with intensive physical therapy, there are no approved neuroprotective/neurorestorative therapies for stroke survivors. Stem cell therapy is a promising treatment for stroke patients and has been the focus of an increasing number of clinical trials over the past two decades. We provide a comprehensive overview of stem cell therapies available to stroke patients, focusing on the different types and doses of stem cells, timing and route of administration, patient selection, clinical outcomes, translational challenges, and future directions for the field. Information on ongoing and completed studies was retrieved from ClinicalTrials.gov, PubMed, Google Scholar, ICTRP, and Scopus. Autologous bone marrow-derived mononuclear cells (BMMNCs) are the most used, followed by autologous bone marrow stromal cells. IV therapy is typically applied in acute to subacute phases, while IT or IC routes are utilized in chronic phases. Although early-phase trials (Phase I/II) indicate strong safety and tolerability, definitive clinical effectiveness has yet to be unequivocally proven. Cochrane meta-analyses show NIH Stroke Scale improvements, though studies often have high bias and small sample sizes. Larger randomized, double-blind, placebo-controlled trials are ongoing to refine stem cell transplantation protocols, addressing cell type and source, dosage, timing, patient selection, the potential for combination therapies, and clinical efficacy.

Development of an Educational Curriculum for Implanting and Managing Vagus Nerve Stimulators for Epilepsy

BACKGROUND

Vagus nerve stimulation (VNS) devices are commonly used for extracranial neuromodulation of drug-resistant epilepsy. These devices are implanted by multiple surgical subspecialties and managed by practitioners with varying levels of epilepsy-specific expertise. The North American Neuromodulation Society (NANS) education committee presents a curriculum defining level-dependent recommendations within the six-core competency rubric for the implantation and management of VNS devices.

MATERIAL AND METHODS

A multidisciplinary (anesthesiology, neurology, neurosurgery, and physiatrists) and diverse (advanced practice providers, physicians, and surgeons) subcommittee of the NANS education committee met virtually over a year to develop a curriculum following the Accreditation Council for Graduate Medical Education (ACGME) core competencies. The subcommittee used a consensus approach, evidence-based development strategy; once completed, the VNS curriculum was approved by the NANS board.

RESULTS

The subcommittee developed a VNS curriculum as a standard to be used for implanting surgeons, managing physicians, and advanced practice providers. The vertical orientation of the curriculum uses the ACGME educational core competencies framework; within this paradigm is a horizontal progression of skills with distinct competency groups for implanting surgeons and/or managing physicians. The horizontal progression defines the expected competence for early learner, advanced learner, and independent practitioner.

CONCLUSION

A NANS education subcommittee iteratively developed a VNS curriculum for defining progressive competence of myriad care providers, including clinicians and advanced practice providers, within the ACGME six core competencies.

Vagus nerve stimulation combined with nerve rehabilitation therapy for upper limb paralysis after hemorrhagic stroke: a stroke-related epilepsy case

BACKGROUND

Hemorrhagic stroke has a high incidence, often leaving patients with significant complications such as limb mobility disorders after treatment. Traditional treatment methods for stroke patients mainly include limb function exercises and hyperbaric oxygen therapy, which have shown effective results. In recent years, there have been reports utilizing vagus nerve stimulation (VNS) to treat limb paralysis in ischemic stroke patients, achieving encouraging outcomes. However, there are rare related reports on hemorrhagic stroke.

CASE PRESENTATION

This report presents a case of a patient who developed left upper limb hemiplegia and recurrent seizures after a hemorrhagic stroke. The patient showed a poor response to standard anti-epileptic treatment and was diagnosed with stroke-related epilepsy. To manage the recurrent seizures, VNS was performed. After the device was activated, the patient reported a significant reduction in abnormal muscle tone and increased mobility impairment in the affected upper limb. Parameters were adjusted, and intermittent stroke electrical stimulation was combined with upper limb rehabilitation exercises. After three months of active treatment, the patient's seizures were well controlled, and there was significant improvement in upper limb function.

CONCLUSIONS

VNS has potential in the rehabilitative treatment of stroke patients with upper limb dysfunction. It is hoped that more patients will benefit from this advanced treatment method in the future, regaining their health and vitality. Additionally, future research needs to further explore the mechanisms and methods of brain remodeling to provide theoretical support and more effective treatment options for stroke patient rehabilitation.

Mechanism and Applications of Vagus Nerve Stimulation

Over the past three decades, vagus nerve stimulation (VNS) has emerged as a promising rehabilitation therapy for a diverse range of conditions, demonstrating substantial clinical potential. This review summarizes the in vivo biological mechanisms activated by VNS and their corresponding clinical applications. Furthermore, it outlines the selection of parameters and equipment for VNS implementation. VNS exhibits anti-inflammatory effects, modulates neurotransmitter release, enhances neural plasticity, inhibits apoptosis and autophagy, maintains blood-brain barrier integrity, and promotes angiogenesis. Clinically, VNS has been utilized in the treatment of epilepsy, depression, headache, stroke, and obesity. Its potential applications extend to anti-inflammatory treatment and the management of cardiovascular and cerebrovascular diseases and various brain disorders. However, further experiments are required to definitively establish the efficacy of VNS's various mechanisms. Additionally, there is a need to explore and identify optimal rehabilitation treatment parameters for different diseases.

Cervical spinal cord stimulation for treatment of upper limb paralysis: a narrative review

Recent advances in cervical spinal cord stimulation (SCS) have demonstrated improved efficacy as a therapeutic intervention for restoring hand functions in individuals with spinal cord injuries or stroke. Accumulating evidence consistently shows that cervical SCS yields significant improvements in grip force, proximal arm strength and muscle activation, with both immediate and sustained effects. This review synthesizes the evidence that electrical stimulations modulate the spinal and supraspinal organization of uninjured descending motor tracts, primarily the residual corticospinal tract, reticulospinal tract and propriospinal network of neurons, as well as increasing the sensitivity of spinal interneurons at the stimulated segments to these inputs. Additionally, we examine contemporary strategies aimed at achieving more precise patterned stimulations, including intraspinal microstimulation, ventral cord stimulation and closed-loop neuromodulation, and discuss the potential benefits of incorporating cervical SCS into a multimodal treatment paradigm.Level of evidence: V.

Targeting the cholinergic anti-inflammatory pathway: an innovative strategy for treating diseases

The cholinergic anti-inflammatory pathway (CAP) is comprised of the vagus nerve, acetylcholine, nicotinic acetylcholine receptors, the spleen, and the splenic nerve. It represents a sophisticated neuroimmune axis that critically regulates the crosstalk between the nervous system and the immune response via the vagus nerve. Here, we provided a nuanced exploration of the CAP's role in curbing inflammatory processes and its broad therapeutic potential across a spectrum of diseases. We meticulously dissect the intricate mechanisms by which the CAP modulates key signaling cascades, including the NF-κB, JAK2/STAT3, MAPK/ERK, PI3K/AKT, COX2/PGE2, and NRF2/HO-1 pathways, which are quintessential in the pathogenesis of various conditions. Additionally, we also summarized the CAP's profound implications in the management of inflammatory diseases, neurodegenerative disorders, metabolic syndromes, and oncological malignancies, elucidating its capacity to mitigate disease severity and progression through sophisticated immune modulation. The modulation of the CAP is suggested as a novel strategy that could potentially transform treatment approaches for a variety of conditions. However, the precise cellular and molecular underpinnings of the CAP's effects, as well as its translatability to clinical settings, remain subjects of ongoing investigation. The review calls for further research to demystify the mechanisms of the CAP and to harness its therapeutic potential fully, with the aim of developing innovative and efficacious treatment modalities that exploit the pathway's unique attributes.

VNS facilitates the neurological function recovery after ischemia/reperfusion injury by regulating the A1/A2 polarization of astrocytes through the NMU-NMUR2 pathway

Stroke is the second leading cause of death worldwide. Although conventional treatments such as thrombolysis and mechanical thrombectomy are effective, their narrow therapeutic window limits long-term neurological recovery. Previous studies have shown that vagus nerve stimulation (VNS) enhances neurological recovery after ischemia/reperfusion (I/R) injury, and neuromedin U (NMU) has neuroprotective effects. This study used a mouse model of cerebral I/R injury to investigate the potential mechanisms of NMU in VNS-mediated neurological improvement. The study consisted of two parts: first, assessing the dynamic expression of NMU and NMUR2, which peaked on day 14 post-I/R. NMUR2 was primarily localized in astrocytes, suggesting that the NMU-NMUR2 signaling pathway plays an important role in astrocyte regulation. Next, interventions with VNS, NMU, and R-PSOP + VNS were conducted to evaluate the role of this pathway in VNS-mediated recovery. The results showed that VNS significantly upregulated NMU and NMUR2 expression, which was blocked by the NMUR2 antagonist R-PSOP. VNS and NMU treatment increased the proportion of A2 astrocytes, reduced A1 astrocytes, and enhanced the expression of VEGF and BDNF, all of which were also blocked by R-PSOP. These findings indicate that the "VNS-NMU-NMUR2-astrocyte A1/A2 polarization-VEGF/BDNF pathway" plays a crucial role in promoting neurovascular remodeling, axonal and dendritic regeneration, and synaptic plasticity, thereby contributing to functional recovery.

Modulation of GABAergic system as a therapeutic option in stroke

Stroke is one of the leading causes of death and permanent adult disability worldwide. Despite the improvements in reducing the rate and mortality, the societal burden and costs of treatment associated with stroke management are increasing. Most of the therapeutic approaches directly targeting ischemic injury have failed to reduce short- and long-term morbidity and mortality and more effective therapeutic strategies are still needed to promote post-stroke functional recovery. Decades of stroke research have been focused on hyperexcitability and glutamate-induced excitotoxicity in the acute phase of ischemia and their relation to motor deficits. Recent advances in understanding the pathophysiology of stroke have been made with several lines of evidence suggesting that changes in the neurotransmission of the major inhibitory system via γ-Aminobutyric acid (GABA) play a particularly important role in functional recovery and deserve further attention. The present review provides an overview of how GABAergic neurotransmission changes correlate with stroke recovery and outlines GABAergic system modulators with special emphasis on neurosteroids that have been shown to affect stroke pathogenesis or plasticity or to protect against cognitive decline. Supporting evidence from both animal and human clinical studies is presented and the potential for GABA signaling-targeted therapies for stroke is discussed to translate this concept to human neural repair therapies. Age and sex are considered crucial parameters related to the pathophysiology of stroke and important factors in the development of therapeutic pharmacological strategies. Future work is needed to deepen our knowledge of the neurochemical changes after stroke, extend the conceptual framework, and allow for the development of more effective interventions that include the modulation of the inhibitory system.

Vagus nerve stimulation for stroke rehabilitation: Neural substrates, neuromodulatory effects and therapeutic implications

Paired vagus nerve stimulation (VNS) has emerged as a promising strategy to potentiate recovery after neurological injury. This approach, which combines short bursts of electrical stimulation of the vagus nerve with rehabilitation exercises, received approval from the US Food and Drug Aministration in 2021 as the first neuromodulation-based therapy for chronic stroke. Because this treatment is increasingly implemented in clinical practice, there is a need to take stock of what we know about this approach and what we have yet to learn. Here, we provide a survey on the foundational basis of VNS therapy for stroke and offer insight into the mechanisms that underlie potentiated recovery, focusing on the principles of neuromodulatory reinforcement. We discuss the current state of observations regarding synaptic reorganization in motor networks that are enhanced by VNS, and we propose other prospective loci of neuromodulation that should be evaluated in the future. Finally, we highlight the future opportunities and challenges to be faced as this approach is increasingly translated to clinical use. Collectively, a clearer understanding of the mechanistic basis of VNS therapy may reveal ways to maximize its benefits.

Stroke as a career option for neurologists

Stroke is one of the most common acute neurological disorders and a leading cause of disability worldwide. Evidence-based treatments over the last two decades have driven a revolution in the clinical management and design of stroke services. We need a highly skilled, multidisciplinary workforce that includes neurologists as core members to deliver modern stroke care. In the UK, the dedicated subspecialty training programme for stroke medicine has recently been integrated into the neurology curriculum. All neurologists will be trained to contribute to each aspect of the stroke care pathway. We discuss how training in stroke medicine is evolving for neurologists and the opportunities and challenges around practising stroke medicine in the UK and beyond.

Mechanisms of vagus nerve stimulation for the treatment of neurodevelopmental disorders: a focus on microglia and neuroinflammation

The vagus nerve (VN) is the primary parasympathetic nerve, providing two-way communication between the body and brain through a network of afferent and efferent fibers. Evidence suggests that altered VN signaling is linked to changes in the neuroimmune system, including microglia. Dysfunction of microglia, the resident innate immune cells of the brain, is associated with various neurodevelopmental disorders, including schizophrenia, attention deficit hyperactive disorder (ADHD), autism spectrum disorder (ASD), and epilepsy. While the mechanistic understanding linking the VN, microglia, and neurodevelopmental disorders remains incomplete, vagus nerve stimulation (VNS) may provide a better understanding of the VN's mechanisms and act as a possible treatment modality. In this review we examine the VN's important role in modulating the immune system through the inflammatory reflex, which involves the cholinergic anti-inflammatory pathway, which releases acetylcholine. Within the central nervous system (CNS), the direct release of acetylcholine can also be triggered by VNS. Homeostatic balance in the CNS is notably maintained by microglia. Microglia facilitate neurogenesis, oligodendrogenesis, and astrogenesis, and promote neuronal survival via trophic factor release. These cells also monitor the CNS microenvironment through a complex sensome, including groups of receptors and proteins enabling microglia to modify neuroimmune health and CNS neurochemistry. Given the limitations of pharmacological interventions for the treatment of neurodevelopmental disorders, this review seeks to explore the application of VNS as an intervention for neurodevelopmental conditions. Accordingly, we review the established mechanisms of VNS action, e.g., modulation of microglia and various neurotransmitter pathways, as well as emerging preclinical and clinical evidence supporting VNS's impact on symptoms associated with neurodevelopmental disorders, such as those related to CNS inflammation induced by infections. We also discuss the potential of adapting non-invasive VNS for the prevention and treatment of these conditions. Overall, this review is intended to increase the understanding of VN's potential for alleviating microglial dysfunction involved in schizophrenia, ADHD, ASD, and epilepsy. Additionally, we aim to reveal new concepts in the field of CNS inflammation and microglia, which could serve to understand the mechanisms of VNS in the development of new therapies for neurodevelopmental disorders.

Effect of a Multicomponent Exercise Intervention on Recovery of Walking Ability in Stroke Survivors: A Systematic Review With Meta-analysis

OBJECTIVE

To evaluate whether multicomponent exercise (MCE) is more effective than single exercise in improving walking ability in patients with stroke.

DESIGN

A systematic review and meta-analysis.

DATA SOURCES

A systematic search of PubMed, Embase, Web of Science, Cochrane Library, and CINAHL from the establishment of each database to February 2024 was performed. A combination of medical subject headings and free-text terms relating to stroke and exercise were searched.

STUDY SELECTION

Randomized controlled trials treating stroke survivors with MCE were included. The control groups received conventional treatments such as conventional treatment or no intervention or sham training; the experimental groups received MCE. The outcome measures were walking endurance, gait speed, and balance ability.

DATA EXTRACTION

The data extraction form was completed by 2 independent reviewers. The risk of bias was assessed using the Cochrane Risk of Bias Tool for randomized controlled trials. Review manager 5.4 software was used for data analysis. Subgroup analysis and sensitivity analysis were used to supplement the results with higher heterogeneity. The preferred reporting project for systematic reviews and meta-analyses 2020 guidelines were followed.

DATA SYNTHESIS

Twelve studies were included. Meta-analyses found that compared with the control group, the MCE significantly affected gait speed (mean difference=0.11; 95% CI, 0.06-0.16; I2=0%), but the effect on balance ability was not statistically significant. Subgroup analysis showed that MCE (≥60min) was effective in improving walking endurance. These results suggest that MCE improves walking endurance and walking speed in patients with stroke.

CONCLUSIONS

MCE helps improve the gait speed of stroke survivors. Prolonging the MCE time may have a better effect on improving the walking endurance of patients with stroke.

The effects of transcutaneous auricular vagus nerve stimulation (taVNS) on cholinergic neural networks in humans: A neurophysiological study

OBJECTIVE

The mechanisms of actions of transcutaneous auricular vagus nerve stimulation (taVNS) are still unclear, however the activity of the cholinergic system seems to be critical for the induction of VNS-mediated plasticity. Transcranial Magnetic Stimulation (TMS) is a well-suited, non-invasive tool to investigate cortical microcircuits involving different neurotransmitters. Herein, we evaluated the effect of taVNS on short-latency afferent inhibition (SAI), a TMS paradigm specifically measuring cholinergic neurotransmission.

METHODS

Fifteen healthy subjects participated in this randomized placebo-controlled double-blind study. Each subject underwent two different sessions of 1-hour exposure to taVNS (real and sham) separated by a minimum of 48 h. Real taVNS was administered at left external acoustic meatus, while sham stimulation was performed at left ear lobe. We evaluated SAI bilaterally over the motor cortex before and after exposure to taVNS.

RESULTS

No side effects were reported by any of the participants. Statistical analysis did not show any significant effect of taVNS on SAI.

CONCLUSIONS

Our study demonstrated that cholinergic circuits explored by SAI are different from circuits engaged by taVNS.

SIGNIFICANCE

Since the influence of VNS on cholinergic neurotransmission has been exhaustively demonstrated in animal models, further studies are mandatory to understand the actual impact of VNS on cholinergic circuits in humans.

Three-dimensional kinematic analysis can improve the efficacy of acupoint selection for post-stroke patients with upper limb spastic paresis: A randomized controlled trial

BACKGROUND

China is seeing a growing demand for rehabilitation treatments for post-stroke upper limb spastic paresis (PSSP-UL). Although acupuncture is known to be effective for PSSP-UL, there is room to enhance its efficacy.

OBJECTIVE

This study explored a semi-personalized acupuncture approach for PSSP-UL that used three-dimensional kinematic analysis (3DKA) results to select additional acupoints, and investigated the feasibility, efficacy and safety of this approach.

DESIGN, SETTING, PARTICIPANTS AND INTERVENTIONS

This single-blind, single-center, randomized, controlled trial involved 74 participants who experienced a first-ever ischemic or hemorrhagic stroke with spastic upper limb paresis. The participants were then randomly assigned to the intervention group or the control group in a 1:1 ratio. Both groups received conventional treatments and acupuncture treatment 5 days a week for 4 weeks. The main acupoints in both groups were the same, while participants in the intervention group received additional acupoints selected on the basis of 3DKA results. Follow-up assessments were conducted for 8 weeks after the treatment.

MAIN OUTCOME MEASURES

The primary outcome was the Fugl-Meyer Assessment for Upper Extremity (FMA-UE) response rate (≥ 6-point change) at week 4. Secondary outcomes included changes in motor function (FMA-UE), Brunnstrom recovery stage (BRS), manual muscle test (MMT), spasticity (Modified Ashworth Scale, MAS), and activities of daily life (Modified Barthel Index, MBI) at week 4 and week 12.

RESULTS

Sixty-four participants completed the trial and underwent analyses. Compared with control group, the intervention group exhibited a significantly higher FMA-UE response rate at week 4 (χ2 = 5.479, P = 0.019) and greater improvements in FMA-UE at both week 4 and week 12 (both P < 0.001). The intervention group also showed bigger improvements from baseline in the MMT grades for shoulder adduction and elbow flexion at weeks 4 and 12 as well as thumb adduction at week 4 (P = 0.007, P = 0.049, P = 0.019, P = 0.008, P = 0.029, respectively). The intervention group showed a better change in the MBI at both week 4 and week 12 (P = 0.004 and P = 0.010, respectively). Although the intervention group had a higher BRS for the hand at week 12 (P = 0.041), no intergroup differences were observed at week 4 (all P > 0.05). The two groups showed no differences in MAS grades as well as in BRS for the arm at weeks 4 and 12 (all P > 0.05).

CONCLUSION

Semi-personalized acupuncture prescription based on 3DKA results significantly improved motor function, muscle strength, and activities of daily living in patients with PSSP-UL.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2200056216. Please cite this article as: Huang XY, Liao OP, Jiang SY, Tao JM, Li Y, Lu XY, Li YY, Wang C, Li J, Ma XP. Three-dimensional kinematic analysis can improve the efficacy of acupoint selection for post-stroke patients with upper limb spastic paresis: A randomized controlled trial. J Integr Med. 2025; 23(1): 15-24.

Priming and task-specific training for arm weakness post stroke: A randomized controlled trial

OBJECTIVE

The objective of this work was to evaluate if task-specific training (TST) preceded by bilateral upper limb motor priming (BUMP) reduces upper limb impairment more than TST preceded by control priming ([CP], sham electrical stimulation) in people with chronic stroke.

METHODS

In this single-blind, randomized controlled trial, 76 adults with moderate to severe upper limb hemiparesis ≥6 months post-stroke were stratified by baseline impairment and randomized to receive either BUMP or CP prior to receiving the same TST protocol. Participants completed 30 h of treatment in 15 days over 6 weeks. The primary outcome was change in Fugl-Meyer upper extremity (FMUE) from baseline to 8-week follow-up. We also report clinically meaningful response rates defined as a change in FMUE score of 6 points or greater.

RESULTS

In response to treatment, both groups improved to a significant extent at follow-up, exceeding the FMUE minimum clinically important difference. Those in BUMP and CP saw a mean change of 5.68 (SE 0.76, p < 0.001) and 5.87 (SE 0.76, p < 0.001) respectively. There was no significant difference between treatment arms (mean difference of -0.20 (95% CI = [-2.37, 1.97], SE = 1.08, p = 0.86)). A response of ≥6 points was observed in 46% in BUMP and 50% in CP.

INTERPRETATION

There was no beneficial effect of BUMP. The magnitude of change seen in both groups reflects the largest improvement achieved with just 22.5 h of TST in this population, matching or out-performing more invasive, time-intensive, and costly interventions proposed in recent years.

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

OBJECTIVE

Vagus 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 METHODS

We 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.

RESULTS

The 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.

CONCLUSIONS

The 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.

Efficacy of Auricular Therapy for Motor Impairment After Stroke: A Systematic Review and Meta-Analysis

BACKGROUND

A high number of stroke patients cannot recover fully from motor impairment despite early rehabilitation. Auricular therapies, usually given by acupuncture doctors or nurses, have been widely used among these post-stroke patients. Potential benefits of auricular therapies were shown in recent clinical trials.

OBJECTIVES

The purpose of this review was to systematically evaluate the clinical effects of auricular therapy in the treatment of post-stroke motor impairment.

METHODS

PubMed, Embase, Web of Science, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Cochrane Library, Chinese Biological Medicine (CBM), Chinese National Knowledge Infrastructure (CNKI) and Wanfang databases were searched from their inception to May 2023. Randomised controlled trials of auricular therapy for the treatment of post-stroke motor impairment met the screening criteria. The primary outcome was the Fugl-Meyer Assessment Scale (FMA). The secondary outcomes included the Fugl-Meyer Assessment Upper Extremity Scale (FMA-UE), Chinese Stroke Scale (CSS), clinical efficacy and the Barthel Index Scale (BI). Meta-analysis was carried out using RevMan software 5.3.

RESULTS

Twenty-eight RCTs with 1993 patients were included. The meta-analysis results suggested that compared with conventional treatment, auricular therapy combined with conventional treatment significantly improved the FMA score (MD: 15.07, 95% CI, 12.56 to 17.59), the FMA-UE score (MD: 6.49, 95% CI, 5.54 to 7.45), the clinical efficacy (RR: 1.20, 95% CI, 1.12 to 1.29) and the BI score (MD: 10.26, 95% CI, 9.11 to 11.40), while the combination treatment significantly decreased the CSS score (MD: -2.98, 95% CI, -4.38 to -1.59).

CONCLUSION

Auricular therapy, as an adjunctive treatment to the conventional treatment, improved post-stroke motor impairment and self-care ability. Early auricular therapy of the patients in the early disease stage may lead to better improvement. Further well-designed, large-size clinical studies are needed.

IMPLICATIONS FOR PRACTICE

This study suggested that auricular therapy could be used as a complementary therapy with conventional treatment for improving motor impairment and self-care ability among post-stroke patients with motor impairment in hospitals, long-term care facilities and homes.

Mechanisms of Vagus Nerve Stimulation in Improving Motor Dysfunction After Stroke

Patients with stroke would have persistent functional deficits despite undergoing physiotherapy and rehabilitation training. Recently, vagus nerve stimulation (VNS), a newly emerging neuroregulatory technique, has been shown to improve motor dysfunction after stroke. Evidence from clinical and preclinical studies has proven the safety, feasibility, and efficacy of invasive and noninvasive VNS. It has been reported that the positive effect may be related to anti-inflammatory effects, mediating neuroplasticity, increasing blood-brain barrier integrity, promoting angiogenesis and reducing spreading depolarization. However, the underlying mechanism remains poorly understood. In this review, we have summarized the potential molecular mechanisms by which VNS promotes stroke prognosis. We believe that VNS combined with upper-extremity rehabilitation can improve impairment and function among moderately to severely impaired stroke survivors. The applications and further exploration are discussed to provide new insights into this novel therapeutic technique.

Improvement of upper limb function in post-stroke patients with motion feedback training-based combination therapy: a retrospective analysis of muscle activation and recovery dynamics

OBJECTIVE

To evaluate the effectiveness of combination therapy based on motion feedback training in patients recovering from ischemic stroke.

METHODS

A retrospective analysis was conducted on 205 patients in the recovery phase of ischemic stroke admitted between June 2022 and June 2023. Patients were divided into two groups: the conventional treatment group (n=101), receiving standard care, and the combination therapy group (n=104), receiving additional motion feedback training for 30 days. Outcome measures included root mean square (RMS) and median frequency (MDF) of surface electromyography (sEMG) for upper limb muscles, biochemical indicators, active range of motion (AROM), Fugl-Meyer Assessment (FMA) scores, and Activities of Daily Living (ADL) scores.

RESULTS

Combination therapy significantly improved post-treatment RMS values in muscles such as the left Biceps brachii (BB) (P=0.008), right BB (P=0.003), and right Flexor pollicis brevis (FPB) (P=0.010). MDF values also improved significantly in the left BB (P=0.002) and left FPB (P=0.027). The combination therapy group showed higher post-treatment SOD levels compared to the conventional group (P=0.001). Significant improvements were observed in AROM (P<0.001), FMA (P<0.001), and ADL scores (P=0.010) in the combination therapy group. Logistic regression analysis revealed that combination therapy was associated with better outcomes (OR, 0.518; 95% CI, 0.291-0.923; P=0.026), while higher pre-treatment right FPB RMS values were linked to poorer prognosis (OR, 1.074; 95% CI, 1.004-1.149; P=0.039).

CONCLUSION

Motion feedback training-based combination therapy significantly enhances muscle activation, antioxidant biochemical pathways, functional recovery, and daily living activities in post-stroke patients compared to conventional treatment alone.

A narrative review of vagus nerve stimulation in stroke

Stroke is a significant health concern impacting society and the health care system. Reperfusion therapy for acute ischemic stroke and standard rehabilitative therapies may not always be effective at improving post-stroke neurological function, and developing alternative strategies is particularly important. Vagus nerve stimulation (VNS) is a treatment option currently approved by the Food and Drug Administration (FDA) for intractable epilepsy, refractory depression, primary headache disorders, obesity, and moderate to severe upper-limb motor dysfunction in chronic ischemic stroke patients. Moreover, VNS has demonstrated potential efficacy in various conditions, including autoimmune diseases, disorders of consciousness, Alzheimer's disease, Parkinson's disease, traumatic brain injury, stroke, and other diseases. Although the popularity and application of VNS continue to increase rapidly, the field generally lacks a consensus on the optimal stimulation parameters. The stimulation parameters for VNS are directly related to the clinical outcome, and determining the optimal stimulation conditions for VNS has become an essential concern in its clinical application. This review summarizes the current evidence on VNS for stroke in preclinical models and clinical trials in humans, paying attention to the current types and stimulation parameters of VNS, highlighting the mechanistic pathways involved in the beneficial effects of VNS, critically evaluating clinical implementation challenges and proposing some suggestions for its future research directions. Achieving safe and effective clinical transformation of VNS requires further animal and clinical studies to determine the optimal stimulation parameters and therapeutic mechanisms.

Vagus nerve stimulation: a physical therapy with promising potential for central nervous system disorders

The diseases of the central nervous system (CNS) often cause irreversible damage to the human body and have a poor prognosis, posing a significant threat to human health. They have brought enormous burdens to society and healthcare systems. However, due to the complexity of their causes and mechanisms, effective treatment methods are still lacking. Vagus nerve stimulation (VNS), as a physical therapy, has been utilized in the treatment of various diseases. VNS has shown promising outcomes in some CNS diseases and has been approved by the Food and Drug Administration (FDA) in the United States for epilepsy and depression. Moreover, it has demonstrated significant potential in the treatment of stroke, consciousness disorders, and Alzheimer's disease. Nevertheless, the exact efficacy of VNS, its beneficiaries, and its mechanisms of action remain unclear. This article discusses the current clinical evidence supporting the efficacy of VNS in CNS diseases, providing updates on the progress, potential, and potential mechanisms of action of VNS in producing effects on CNS diseases.

Research hotspots and frontiers of vagus nerve stimulation in stroke: a bibliometric analysis

Background

Vagus nerve stimulation (VNS) has emerged as a promising therapeutic approach for stroke treatment, drawing significant attention due to its potential benefits. However, despite this growing interest, a systematic bibliometric analysis of the research landscape is yet to be conducted.

Methods

We performed a comprehensive search of the Web of Science Core Collection (WoSCC) database for literature published between January 1, 2005, and August 31, 2024. CiteSpace and the Bibliometrix package in R software were used to generate knowledge maps and conduct a bibliometric analysis. This analysis focused on publication output, geographic distribution, institutional involvement, author and co-cited author networks, journal and co-cited journal relationships, co-cited references, and keyword trends.

Results

During the study period, 316 publications on VNS in stroke were identified, authored by 1,631 researchers from 1,124 institutions across 172 countries or regions. The number of publications showed steady growth, with the United States of America (USA) leading as the primary contributor. The University of Texas System emerged as the most active research institution. Frontiers in Neuroscience published the highest number of articles, while Stroke had the most citations. Professor Michael P. Kilgard authored the largest number of papers and was also the most frequently cited researcher. The main research trends focus on investigating VNS mechanisms via animal models and exploring its application in improving post-stroke sensorimotor function in the upper limbs. Moreover, VNS is showing promise in enhancing non-motor functions, such as swallowing, speech, and cognition, while addressing complications like post-stroke insomnia, depression, and disruptions in gut microbiota.

Conclusion

This bibliometric study offers a comprehensive overview of the research landscape and emerging trends in VNS for stroke rehabilitation, providing a solid foundation and reference point for future research directions in this field.

Vagus nerve stimulation (VNS): recent advances and future directions

PURPOSE

Vagus nerve stimulation (VNS) is emerging as a unique and potent intervention, particularly within neurology and psychiatry. The clinical value of VNS continues to grow, while the development of noninvasive options promises to change a landscape that is already quickly evolving. In this review, we highlight recent progress in the field and offer readers a glimpse of the future for this bright and promising modality.

METHODS

We compiled a narrative review of VNS literature using PubMed and organized the discussion by disease states with approved indications (epilepsy, depression, obesity, post-stroke motor rehabilitation, headache), followed by a section highlighting novel, exploratory areas of VNS research. In each section, we summarized the current role, recent advancements, and future directions of VNS in the treatment of each disease.

RESULTS

The field continues to gain appreciation for the clinical potential of this modality. VNS was initially developed for treatment-resistant epilepsy, with the first depression studies following shortly thereafter. Overall, VNS has gained approval or clearance in the treatment of medication-refractory epilepsy, treatment-resistant depression, obesity, migraine/cluster headache, and post-stroke motor rehabilitation.

CONCLUSION

Noninvasive VNS represents an opportunity to bridge the translational gap between preclinical and clinical paradigms and may offer the same therapeutic potential as invasive VNS. Further investigation into how VNS parameters modulate behavior and biology, as well as how to translate noninvasive options into the clinical arena, are crucial next steps for researchers and clinicians studying VNS.

Effects of robot-assisted arm training on respiratory muscle strength, activities of daily living, and quality of life in patients with stroke: a single-blinded randomized controlled trial

BACKGROUND

Post-stroke clinical changes not only affect extremities and trunk muscles but also the respiratory muscles.

PURPOSE

To determine the effect of robot-assisted arm training with conventional rehabilitation (CombT) on respiratory muscle strength, activities of daily living (ADL), and quality of life in patients with stroke and to compare the results with conventional rehabilitation (CR).

METHODS

It was a two-arm, single-blinded, randomized controlled trial in which 66 patients were randomly allocated to either CombT or CR to receive 30 sessions (5/week) over 6 weeks. The respiratory muscle strength (maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP)), activities of daily life (ABILHAND questionnaire), and quality of life (Stroke Impact Scale (SIS)) were measured before and 6 weeks after training.

RESULTS

The CombT group showed significantly better MIP, MEP, and performance in ADLs after 6 weeks of training compared to the CR group (p < .01). The effect size was large for MIP (d = 0.9) and MEP (d = 0.9), whereas medium for performance in ADLs (d = 0.62). Also, the SIS-arm strength (p < .01), hand function (p = .04), ADLs (p = .02), and recovery (p = .04) were significantly better in CombT group with a medium (d = 0.6, d = 0.5, d = 0.5, and d = 0.5, respectively) effect size compared with CR group.

CONCLUSIONS

Both CombT and CR groups improved respiratory muscle strength, performance in ADLs, and quality of life in patients with stroke. However, CombT appears to offer more comprehensive benefits, highlighting its valuable role in respiratory and functional recovery after stroke.