The effect of transcutaneous auricular vagus nerve stimulation on vigilance, cognition, and mood during military exercise with acute sleep deprivation.

To investigate the combined effect of transcranial magnetic stimulation (TMS) and transcranial direct current stimulation on improving lower limb function in stroke patients. Randomized controlled trial. Subacute stroke patients. 169 post-stroke hemiplegia patients were randomly divided into 4 groups (control, transcranial direct current stimulation, transcutaneous auricular vagus nerve stimulation, and transcutaneous auricular vagus nerve stimulation combined with transcranial direct current stimulation) and evaluated using the Fugl-Meyer Assessment-Lower Extremity (FMA-LL), Timed Up-and-Go (TUG) test, Modified Barthel Index (MBI), Berg Balance Scale (BBS), gait parameters, and surface electromyography (sEMG). Significant improvements in FMA-LL, MBI, BBS, TUG, gait parameters, and sEMG were noted in the intervention groups compared with the control, with the transcutaneous auricular vagus nerve stimulation combined with transcranial direct current stimulation group showing the most pronounced improvements. Differences in some outcomes were also notable between the transcutaneous auricular vagus nerve stimulation and transcranial direct current stimulation groups. The combination of transcutaneous auricular vagus nerve stimulation and transcranial direct current stimulation effectively enhances gait, balance, and daily living activities in subacute stroke patients. These benefits are likely due to transcutaneous auricular vagus nerve stimulation activating the solitary and trigeminal nuclei and transcranial direct current stimulation stimulating the motor cortex. Wearable gait analysis systems and electromyography are valuable in clinical gait assessment for these patients.

Among the noninvasive electrical stimulation methods, transcutaneous auricular vagus nerve stimulation (taVNS) regulates the activity of various neural networks in the brain and autonomic nervous system and is expected to be applied clinically in many areas, including in patients with central nervous system, psychiatric, and cardiac diseases. Although systematic reviews and meta-analyses have been conducted on safety and efficacy, the variability of stimulation parameters and the lack of consistency in their effects remain significant issues. Therefore, the present study aimed to provide a comprehensive view of the safety, parameters, and efficacy of taVNS by focusing on studies in healthy participants, patients with stroke, and patients with Parkinson’s disease. A literature search was conducted from October 14 to 25 November 2024, using PubMed, Google Scholar, Web of Science, the Cochrane Library, and Scopus. The following search terms were used: “noninvasive VNS or nVNS or noninvasive vagus nerve stimulation,” “transcutaneous vagus nerve stimulation or tVNS,” and “transcutaneous auricular vagus nerve stimulation or taVNS.” In total, 154 papers were included, of which 139 were on healthy participants, nine on patients with stroke, and six on patients with Parkinson’s disease. The safety of taVNS was relatively high. Although minor side effects were reported, no serious adverse events were attributed to taVNS parameters used. taVNS could regulate brain activity, motor and mental functions, and autonomic nervous system activity in patients with stroke and Parkinson’s disease. Modulation of the autonomic nervous system and cortical excitability was also observed in healthy individuals. However, these effects may depend on the stimulation parameters. The lack of reports on safety and the stimulation parameters used was also highlighted. Further validation of parameters and accumulation of evidence regarding the efficacy of taVNS are necessary.

This systematic review aimed to evaluate the effect of transcutaneous auricular vagus nerve stimulation on heart rate variability and baroreflex sensitivity in healthy populations. PubMed, Scopus, the Cochrane Library, Embase, and Web of Science were systematically searched for controlled trials that examined the effects of transcutaneous auricular vagus nerve stimulation on heart rate variability parameters and baroreflex sensitivity in apparently healthy individuals. Two independent researchers screened the search results, extracted the data, and evaluated the quality of the included studies. From 2458 screened studies, 21 were included. Compared with baseline measures or the comparison group, significant changes in the standard deviation of NN intervals, the root mean square of successive RR intervals, the proportion of consecutive RR intervals that differ by more than 50ms, high-frequency power, low-frequency to high-frequency ratio, and low-frequency power were found in 86%, 75%, 69%, 47%, 36%, and 25% of the studies evaluating the effects of transcutaneous auricular vagus nerve stimulation on these indices, respectively. Baroreflex sensitivity was evaluated in six studies, of which a significant change was detected in only one. Some studies have shown that the worse the basic autonomic function, the better the response to transcutaneous auricular vagus nerve stimulation. The results were mixed, which may be mainly attributable to the heterogeneity of the study designs and stimulation delivery dosages. Thus, future studies with comparable designs are required to determine the optimal stimulation parameters and clarify the significance of autonomic indices as a reliable marker of neuromodulation responsiveness.

As our world is becoming more globally connected, the ability to speak another language is increasingly becoming a valuable skill. While there exist many training programs to help acquire a new language, this task becomes increasingly difficult with age—thus presenting the need for a novel method of intervention to assist in this process. Considering this increasing difficulty and poor outcomes of existing methods, a new biologically based intervention could be valuable for improving learning and memory. Previous research conducted in our lab has shown that noninvasive transcutaneous auricular vagus nerve stimulation (taVNS) is an effective intervention in memory-based reading comprehension and letter-sound learning (Thakkar et al., 2020;2023). TaVNS has also been shown to boost associative memory (Jacobs et al., 2015), spatial working memory (Sun et al., 2021), and emotional memory (Ventura-Bort et al., 2021). Despite this knowledge, little is known about taVNS and its effects on long-lasting language retention. Thus, this current study explores whether transcutaneous auricular vagus nerve stimulation can improve learning and retention of vocabulary words in a new language when paired with a training routine. Typically developing college-aged individuals were recruited through an online participant pool. All individuals were screened for age, IQ, reading, memory, and attention for inclusion in this study. The participants completed a one-hour training session in which they were presented with 30 Palauan nouns, the respective English translations, as well as images of the nouns. During this time, the participants received sham, 5 Hz, or 25 Hz stimulation to the posterior of the left tragus. Prior to training, participants completed a translation test to measure their existing knowledge of the Palauan language, and this test was repeated immediately after training and again seven days later to measure learning and retention. After analysis of the results, no effect was found for any stimulation group immediately after training. At retention, however, the 25 Hz taVNS group showed significantly greater performance than both the sham and 5 Hz taVNS groups on recall of material. There was also no statistical difference between the performance of the sham and 5 Hz taVNS groups. Lastly, the results further suggest that stimulation intensity does not impact the efficacy of the intervention. These data suggest that taVNS, regardless of stimulation intensity, may be used to help in the retention of novel words in a new language. These data will be important for ongoing research examining the uses of taVNS, its use as an intervention for learning and retention of a new language, as well as its potential uses in other areas of cognition.

"As our world is becoming more globally connected, the ability to speak another language is increasingly becoming a valuable skill. While there exist many training programs to help acquire a new language, this task becomes increasingly difficult with age– thus presenting the need for a novel method of intervention to assist in this process. Considering this increasing difficulty and poor outcomes of existing methods, a new biologically based intervention could be valuable for improving learning and memory. Previous research conducted in our lab has shown that noninvasive transcutaneous auricular vagus nerve stimulation (taVNS) is an effective intervention in memory-based reading comprehension and letter-sound learning (Thakkar et al., 2020;2023). TaVNS has also been shown to boost associative memory (Jacobs et al., 2015), spatial working memory (Sun et al., 2021), and emotional memory (Ventura-Bort et al., 2021). Despite this knowledge, little is known about taVNS and its effects on long-lasting language retention. Thus, this current study explores whether transcutaneous auricular vagus nerve stimulation can improve learning and retention of vocabulary words in a new language when paired with a training routine. Typically developing college-aged individuals were recruited through an online participant pool. All individuals were screened for age, IQ, reading, memory, and attention for inclusion in this study. The participants completed a one-hour training session in which they were presented with 30 Palauan nouns, the respective English translations, as well as images of the nouns. During this time, the participants received sham, 5 Hz, or 25 Hz stimulation to the posterior of the left tragus. Prior to training, participants completed a translation test to measure their existing knowledge of the Palauan language, and this test was repeated immediately after training and again seven days later to measure learning and retention. After analysis of the results, no effect was found for any stimulation group immediately after training. At retention, however, the 25 Hz taVNS group showed significantly greater performance than both the sham and 5 Hz taVNS groups on recall of material. There was also no statistical difference between the performance of the sham and 5 Hz taVNS groups. Lastly, the results further suggest that stimulation intensity does not impact efficacy of the intervention. These data suggest that taVNS, regardless of stimulation intensity, may be used to help in the retention of novel words of a new language. These data will be important for ongoing research examining the uses of taVNS, its use as an intervention for learning and retention of a new language, as well as its potential uses in other areas of cognition."

Transcutaneous auricular vagus nerve stimulation for managing pain: A scoping review

A SENSORY CORTICAL REPRESENTATION OF THE VAGUS NERVE: WITH A NOTE ON THE EFFECTS OF LOW BLOOD PRESSURE ON THE CORTICAL ELECTROGRAM

Background: This study was developed to determine the effectiveness of transcutaneous auricular vagus nervestimulation and Jacobson relaxation technique on agoraphobia among subjects with post neurological ill-patients.Purpose: The purpose of the study is to compare and evaluate the effectiveness of two non-pharmacologicalmethods of treatment for Agoraphobia patients with Post neurological ill-patients.Methods: The research project was conducted as a pilot study in a private hospital in Chennai. The experimentalgroup (group A) received transcutaneous auricular vagus nerve stimulation for approximately 20 minutes (30seconds ON and 5 minutes OFF) and a conventional Jacobson relaxation technique for 10 minutes. Group B gotconventional cognitive behavioral therapy (20 minutes) and the Jacobson relaxation technique (10 minutes).Following the four-week treatment period, a post-test analysis was performed using the Severity measure ofagoraphobia.Results: The study found that there is a positive impact of transcutaneous auricular vagus nerve stimulation andJacobson relaxation technique on agoraphobia in post neurological ill patients. The analysis obtained a mean valueof about 18 and an SD of 26 for group A, whereas group B revealed 24.8 ± 4.40, mean ± SD, and a significant Pvalue of <0.001.Conclusion: When compared to group B, those in group A who received transcutaneous auricular vagus nervestimulation improved more significantly when dealing with agoraphobia of post neurological ill patients. As aresult, non-invasive transcutaneous auricular vagus nerve stimulation and Jacobson relaxation technique havebeen proven to be effective approaches for preventing agoraphobia.

Transcutaneous auricular vagus nerve stimulation (taVNS) is a promising technique for modulating vagal afferent fibers non-invasively and has shown therapeutic potential in neurological, cognitive, and affective disorders. While previous research highlights its efficacy, the safety profile of taVNS has been less extensively examined. This study therefore aimed to systematically investigate side effects of taVNS in a large pooled dataset consisting of n = 488 participants, utilizing a standardized questionnaire to assess ten reported side effects. Analyses included effects of stimulation type (interval vs. continuous), stimulation duration, stimulation intensity and participant characteristics (age and gender) as potential modulators. The findings support the safety of taVNS, with minimal and mild side effects reported across participants (M = 1.86, SD = 1.36). Although participants receiving sham stimulation were 32.4% less likely to report unpleasant feelings compared to participants receiving taVNS, this effect was driven primarily by low-end ratings (specifically, a rating of 1, indicating not at all when experiencing the corresponding side effect), thus suggesting limited clinical relevance. Interval stimulation notably reduced the likelihood of some side effects, particularly for neck pain, dizziness and unpleasant feelings, suggesting potential for optimizing taVNS protocols. Stimulation intensity and duration showed few statistically significant, but clinically minimal (i.e., very small) effects. Overall, these findings demonstrate a favorable safety profile of taVNS, with mostly mild and transient effects, supporting its use as a suitable non-invasive tool in both research and clinical applications.

Healthcare workers (HCWs) have been significantly impacted by the pandemic. Elderly health care workers carry out a variety of duties at work and have years of clinical expertise. Anxiety and insomnia are among the more commonly encountered problems in senior physicians and other geriatric medical professional populations. The study aims to determine the effect of vagal nerve stimulation on anxiety and sleep disturbances among geriatric medical professionals. 42 participants were enrolled in this study based on the inclusion and exclusion criteria. The participants were divided into two groups using the closed envelope approach, and they took part in therapy sessions lasting 30 minutes, three times per week for a period of four weeks. The Experimental group A received non-invasive transcutaneous auricular vagal nerve stimulation (taVNS) and Control group A received Jacobson's progressive muscle relaxation technique. With a p value of 0.001, taVNS stimulation significantly improved sleep quality and reduced anxiety after 4 weeks. The post-intervention assessment revealed a highly significant improvement in Group A, with a T value of 251 (p < 0.001). The findings suggest that taVNS may be an effective intervention for addressing anxiety and sleep issues in geriatric medical professionals. These results contribute to the exploration of non-invasive strategies to enhance the well-being of healthcare professionals working in demanding environments.

BackgroundTranscutaneous electrical nerve stimulation (TENS) is a non-invasive modality that utilizes electrical currents to modulate pain in populations with acute and chronic pain. TENS has been demonstrated to produce hypoalgesic effects in postoperative pain, fibromyalgia, knee osteoarthritis, and healthy subjects. Transcutaneous auricular vagus nerve stimulation (TaVNS) is a non-invasive modality that modulates the vagus nerve by stimulating its auricular branches. The effects of the combination of TENS and TaVNS on producing an analgesic response have not been studied. Considering that TENS and TaVNS both stimulate similar analgesic pathways but through different means of activation, we can hypothesize that a combination of both methods can produce a more pronounced analgesic response. Therefore, the objective of this study is to assess the hypoalgesic effect of a combination of TENS and TaVNS in pain-free subjects.Methods/designThe study will be a simple crossover design conducted at the University of Hartford. Subjects will be recruited from the University of Hartford population via oral communication, digital flyers, and posters on campus. Thirty participants will undergo two sessions in a crossover manner with one week in between. During one session, the participants will receive TENS with active TaVNS and the other session will be a placebo procedure (TENS with placebo TaVNS). The order of these sessions will be randomized. Importantly, the pressure pain threshold (PPT) and heat pain threshold (HPT) assessors will be blinded to the treatment category. For active TaVNS, a frequency of 25 Hz will be applied with a pulse duration of 200 µs. For placebo TaVNS, the intensity will be increased to a sensory level and then decreased to 0 mA. High-frequency TENS of 100 Hz will be applied in both sessions, with a pulse duration of 200 µsec, asymmetrical biphasic square waveform, and intensity of maximal tolerance without pain. TENS and TaVNS will be turned on for 30 min after a baseline measurement of outcomes. TENS and TaVNS will then be turned off, but the electrodes will remain on until completion of post-treatment assessment. Pressure pain threshold, heat pain threshold, blood pressure, oxygen saturation, and heart rate will be tested 4 times: Once pre-intervention, once during intervention, once immediately after the intervention, and once 15 min post-intervention. Statistical analysis of the data obtained will consider a significance level of p < 0.05.DiscussionThis study will provide evidence concerning the combined effects of TENS and TaVNS on pain threshold in pain-free participants. Based on the outcomes, a greater understanding of how TENS and TaVNS, when used in conjunction, can modulate pain pathways.Trial registrationClinicalTrials.gov NCT06361381. Registered on 09 April 2024.

Non-invasive transcutaneous auricular vagus nerve stimulation (taVNS) has attracted increasing interest as a neurostimulation tool with potential applications in modulating cognitive processes such as attention and memory, possibly through the modulation of the locus-coeruleus noradrenaline system. Studies examining the P300 brain-related component as a correlate of noradrenergic activity, however, have yielded inconsistent findings, possibly due to differences in stimulation parameters, thus necessitating further investigation. In this event-related potential study involving 61 participants, therefore, we examined how changes in taVNS parameters, specifically stimulation type (interval vs. continuous stimulation) and duration, influence P300 amplitudes during a visual novelty oddball task. Although no effects of stimulation were found over the whole cluster and time window of the P300, cluster-based permutation tests revealed a distinct impact of taVNS on the P300 response for a small electrode cluster, characterized by larger amplitudes observed for easy targets (i.e., stimuli that are easily discernible from standards) following taVNS compared to sham stimulation. Notably, our findings suggested that the type of stimulation significantly modulated taVNS effects on the P300, with continuous stimulation showing larger P300 differences (taVNS vs. sham) for hard targets and standards compared to interval stimulation. We observed no interaction effects of stimulation duration on the target-related P300. While our findings align with previous research, further investigation is warranted to fully elucidate the influence of taVNS on the P300 component and its potential utility as a reliable marker for neuromodulation in this field.

Background &amp; objective: Low back pain is a common problem, especially in the young and middle-aged working people, and is often very resistant to the conventional management. We evaluated the impact of transcutaneous auricular vagus nerve stimulation (tVNS), applied in conjunction with an exercise treatment program, on disability in chronic low back pain patients.&#x0D; Methodology: The study was conducted from June to October 2022. Twenty-two patients aged 42.18 ± 9.91 y, with Numerical Pain Rating Scale (NPRS) score 5.64 ± 1.09 and Roland Morris Disability Questionnaire (RMDQ) score 10 ± 4.670, were randomly assigned to two groups. The control group received only exercise therapy (EXC group, n = 11), and the intervention group received exercise and tVNS therapy (EXC + tVNS group, n = 11). The primary outcome was RMDQ, measured before and after the intervention.&#x0D; Result: The mean RMDQ was significantly improved in both groups. In the intervention group the improvement was from 9.45 ± 4.44 to 2.18 ± 2.71 (P = 0.000), in the control group it was from 10.55 ± 5.05 to 2.36 ± 2.06 (P = 0.001). Inter-group comparison showed no significant difference. The effect size of the control group (2.12) was similar with the intervention group (1.98).&#x0D; Conclusion: Addition of 2-weeks tVNS to exercise therapy did not show superior effect on disability improvement compared to exercise only in chronic low back pain. Exercise alone was sufficient to improve the mean RMDQ.&#x0D; Abbreviations: CLBP: Chronic low back pain; EXC: Exercise; tVNS: Transcutaneous auricular vagus nerve stimulation; NPRS: Numerical pain rating scale; RMDQ: Roland Morris disability questionnaire&#x0D; Key words: Chronic low back pain; Disability; Exercise; Transcutaneous Auricular Vagus Nerve Stimulation&#x0D; Citation: Uzlifatin Y, Arfianti L, Wardhani IL, Hidayati HB, Melaniani S. Effect of transcutaneous auricular vagus nerve stimulation in addition to exercise on disability in chronic low back pain patients: a randomized controlled study. Anaesth. pain intensive care 2022;27(1):73−81; DOI: 10.35975/apic.v27i1.2084&#x0D; Received: December 07, 2022; Reviewed: December 28, 2022; Accepted: January 11, 2022

Traumatic brain injury (TBI) is a leading cause of death and disability worldwide. Although TBI pathophysiology has been thoroughly investigated, the effectivity of therapeutic approaches for TBI is still lacking. Our group has developed a novel approach of noninvasive transcutaneous auricular vagus nerve stimulation (taVNS) in a mouse model of TBI to investigate its impact on neuroinflammation. A murine-controlled cortical impact model was used, and results were analyzed on postinjury days (PIDs) 3 and 7. The experimental groups included (1) sham C57BL/6 wild type (WT), (2) TBI wild type, (3) sham-taVNS, and (4) TBI-taVNS. The animals underwent anesthesia, off-site stimulation, or taVNS for 30 minutes. The short- and long-term groups received two sessions of taVNS treatment and were tested on PIDs 3 and 7, respectively. A combination of real-time polymerase chain reaction and immunohistochemistry was used to validate the success of the model and to quantify gene expression associated with microglial and astrocyte activation. Student's t test and one-way analysis of variance were used for statistical analysis, with significance achieved when p < 0.05. Transcutaneous auricular vagus nerve stimulation (VNS) activated the solitary tract nucleus and the dorsal motor nucleus of the vagus nerve as evidenced by a significant upregulation of the neuronal activation marker c-Fos, indicating vagus nerve activation. Transcutaneous auricular VNS treatment reduced the expression of pro-inflammatory microglial markers Tnf (1.69 ± 0.17 vs. 3.615 ± 0.86, p < 0.05) and Lcn2 (64.15 ± 14 vs. 337.7 ± 104.8, p < 0.01) in the ipsilateral injured cortex on PIDs 3 and 7, respectively. Transcutaneous auricular VNS also increased the expression of anti-inflammatory microglial marker Arg1 (55 ± 6.47 vs. 30.49 ± 3.94, p < 0.01) and astrocyte Gfap reactivity (8,582 ± 826 vs. 4,569 ± 554.3, p < 0.01) on PID 3. ( J Trauma Acute Care Surg . 2026;100: 707-713. Copyright © 2025 Wolters Kluwer Health, Inc. All rights reserved.).

Background/Objectives: Transcutaneous auricular vagus nerve stimulation (TaVNS) is a non-invasive method of electrical stimulation used to autonomic neuromodulation. Position and form of the electrodes are important for the effectiveness of autonomic modulation. This study was aimed to investigate the effect of TaVNS in-ear and behind-ear on autonomic variables. Methods: A total of 76 healthy participants (male: 40, female: 36) were randomized into four groups as in-ear TaVNS, behind-ear TaVNS, in-ear sham, and behind-ear sham. The TaVNS protocol included bilateral auricular stimulation for 20 min, 25 hertz frequency, a pulse width of 250 μs, and a suprathreshold current (0.13-50 mA). Heart rate (HR), systolic and diastolic blood pressure (SBP and DBP), and heart rate variability (HRV) were measured baseline and after stimulation. The parameters RMSSD (root mean square of consecutive differences between normal heartbeats), LF power (low-frequency), and HF power (high-frequency) were assessed in the HRV analysis. Results: HR decreased in the in-ear TaVNS after intervention (p < 0.05), but did not change in behind-ear TaVNS and sham groups compared to baseline (p > 0.05). SBP and DBP decreased and RMSSD increased in the in-ear and behind-ear TaVNS groups (p < 0.05), but did not change in sham groups compared to baseline (p > 0.05). There was no significant difference in LF and HF power after TaVNS compared to baseline in all groups (p > 0.05). SBP was lower and RMSSD was higher in-ear TaVNS than behind-ear TaVNS after intervention (p < 0.05). Conclusions: In-ear TaVNS appears to be more effective than behind-ear TaVNS in modulating SBP and RMSSD, but this needs to be studied in larger populations.