Non-invasive Vagus Nerve Stimulation Research Articles

The Role of CGRP Monoclonal Antibodies in the Treatment of Acute Cluster Headache

This article discusses the role of Calcitonin Gene-Related Peptide antagonists available on the market in treating cluster headaches. All the treatments discussed in this article focus on either abortive, preventive, or transitional care. These therapies include Monoclonal Antibodies (Galcanezumab, Fremanezumab, Erenumab), high-flow oxygen, triptans (sumatriptan, zolmitriptan), Octreotide, non-invasive vagus nerve stimulation (vagus and sphenopalatine nerves), and other medications like dihydroergotamine, lidocaine, and capsaicin. We reviewed many studies from The United States since 2015; analytical methods were utilized. Moreover, we found that some of the treatment options for CH can vary depending on efficacy and route of administration and according to categories of therapy (acute or preventive). Every treatment has a specific and unique mechanism of action, indications, contraindications, and side effects. Therefore, the recommendation of one particular treatment should be considered in the success of the treatment of Cluster Headaches. Monoclonal Antibodies against CGRP have a unique role and are considered a first alternative in treating acute CH.

Non-invasive cervical vagus nerve stimulation effects on reaction time and valence image anticipation response

BackgroundNorepinephrine (NE) driven noninvasive vagus nerve stimulation (nVNS), which improves attention and reduces reaction time, augments learning. Equally important, endogenous NE mediated arousal is highly dependent on the valence (positive or negative) of the exogenous stimulus. But to date, no study has measured valence specific effects of nVNS on both functional magnetic resonance imaging (fMRI) anticipation task response and reaction time in healthy individuals. Therefore, the aim of this pilot study was to assess whether nVNS vs sham modulates valence cortical anticipation task response and reaction time in a normative sample. MethodsParticipants received right sided transcutaneous cervical nVNS (N = 12) or sham (N = 12) stimulation during a 3T fMRI scan. Subjects first performed a continuous performance task (CPT) and then a cued anticipation task to images of positively and negatively valenced events during fMRI. Reaction times to cues and Blood oxygen level dependent (BOLD) response were examined over phase to identify effects of nVNS/sham over time. ResultsnVNS reduced reaction time for all valenced image anticipation trials. With the fMRI anticipation task, we observed a valence-specific effect; nVNS increased responsivity to images with negative valence and decreased responsivity to images with positive valence, whereas sham showed an inverse valence response. ConclusionsnVNS was linked to reduced reaction time during the anticipation task. In tandem, nVNS consistently enhanced responsivity to negatively valenced images and diminished responsivity to positively valenced images, suggesting specific nVNS driven endogenous neurotransmitter signaling may contribute.

Non-invasive vagus nerve stimulation in epilepsy patients enhances cooperative behavior in the prisoner’s dilemma task

The vagus nerve constitutes a key link between the autonomic and the central nervous system. Previous studies provide evidence for the impact of vagal activity on distinct cognitive processes including functions related to social cognition. Recent studies in animals and humans show that vagus nerve stimulation is associated with enhanced reward-seeking and dopamine-release in the brain. Social interaction recruits similar brain circuits to reward processing. We hypothesize that vagus nerve stimulation (VNS) boosts rewarding aspects of social behavior and compare the impact of transcutaneous VNS (tVNS) and sham stimulation on social interaction in 19 epilepsy patients in a double-blind pseudo-randomized study with cross-over design. Using a well-established paradigm, i.e., the prisoner’s dilemma, we investigate effects of stimulation on cooperative behavior, as well as interactions of stimulation effects with patient characteristics. A repeated-measures ANOVA and a linear mixed-effects model provide converging evidence that tVNS boosts cooperation. Post-hoc correlations reveal that this effect varies as a function of neuroticism, a personality trait linked to the dopaminergic system. Behavioral modeling indicates that tVNS induces a behavioral starting bias towards cooperation, which is independent of the decision process. This study provides evidence for the causal influence of vagus nerve activity on social interaction.

The Feasibility and Potential Value of Electroacupuncture in Treating Vestibular Migraine

A recent study indicates that noninvasive vagus nerve stimulation (nVNS) may ameliorate vertigo and headache as well as nystagmus associated with vestibular migraine (VM) attacks.1 Notably, electroacupuncture may have some commonality with nVNS as a form of neurostimulation. Moreover, in reference to a previous study published in Neuromodulation,2 cumulative evidence has demonstrated that electroacupuncture can modulate neural plasticity, thereby implying that electroacupuncture could be a potential therapy for treating neural diseases such as VM.

Non-invasive vagus nerve stimulation attenuates the burnout

IntroductionVagus nerve stimulation produces therapeutic effects for the treatment of psychiatric disorders, heart failure, and others.ObjectivesThe aim of the current study was to evaluate the effects of the non-invasive vagus nerve stimulation on emotional burnout.Methods6 right-handed male volunteers aged 18-22 years participated in study. We used the combination of pleasant meditative classical music and a slow bi-polar wave (0.1-0.2 Hz) of electrical non-invasive transcutaneous auricular vagus nerve stimulation for 5 minutes. The set of 4 VNS was performed at intervals of 3 days. EEG was registered during the rest state (3 min, closed eyes condition). To measure the severity of emotional burnout in students, we used the 22-item Maslach Burnout Inventory (MBI).ResultsVNS significantly improve the depersonalization and reduction of personal achievements (components of the emotional burnout). Changes in the psychoemotional state of the respondents were accompanied by the increase in the theta-Fz/alpha-Pz ratio, that reflects an enhancement of the activation level. A set of non-invasive stimulation of the auricular branch of the vagus nerve leads to an increase in the level of activation (the ratio of beta / alpha rhythms). The changes in the power of the alpha rhythm may relate to improving of mental process, creativity, creative thinking. An increase in alpha rhythm may reflect internally oriented attention in creative activities.ConclusionsThe preliminary data suggests that the novel mastoid stimulation device may have a prolonged stimulating effect on the brain processes while attenuating the burnout at the same time.DisclosureNo significant relationships.

Autonomic Dysregulation in Individuals With Psychiatric Disorders and Healthy Controls: Results From the CAP-MEM Observational Cohort

AimsPsychiatric disorders are associated with fatigue and with impairment to a range of cognitive domains, including executive functioning, learning, memory and complex attention. Similar impairments are seen in autonomic nervous system (ANS) dysfunction. The aetipathogenic significance of this for psychiatric disorders is unknown. The main aim of the cap-mem study was to characterize the relationships between ANS and cognitive function in a sample of none-clinical controls and people with mental health, neurodevelopmental and neurodegenerative disorders. The potentially confounding role of medication was included within this analysis.MethodsThe sample was recruited via secondary care mental health trusts. ANS function was assessed using self-report measures of ANS dysfunction symptoms (COMPASS-31) and fatigue (VAFS). Cognitive ability in various domains was measured using a validated, computerised assessment tool (THINC-IT). Psychiatric status and medication status were self-reported, and where possible, disorder severity measured using a rating scale (CGI-S).ResultsParticipants with depression had a significantly higher COMPASS-31 and VAFS scores (higher being more severe), with effect sizes being medium to large. Medication did not fully explain the associations observed. Overall, participants with mental health disorders, when compared to healthy controls, had significantly higher levels of cognitive impairment. Levels of ANS dysfunction significantly and positively correlated with cognitive impairment. The severity of the psychiatric disorder significantly correlated with both ANS dysfunction (p < 0.001) and cognitive impairment. These results were found across all cognitive tests (p < 0.05), other than reaction times in the N-back test, a measure of working memory.ConclusionOur results show significant association between ANS dysfunction, psychiatric disorders and cognitive impairments. This is consistent with previously published data. There is now a need to understand the underlying mechanisms and the directionality of the associations. If these mechanisms are shared and relate to autonomic dysfunction, targeted treatments addressing this directly could be helpful with mental health disorders and associated burdensome symptoms, such as cognitive impairments and fatigue. This study is part of a wider project assessing cognitive ability and autonomic functioning in psychiatric populations, and investigating treatments that directly address autonomic dysfunction in psychiatric samples, such as non-invasive transauricular vagus nerve stimulation (taVNS).

Increased Concentrations of Circulating Interleukins following Non-Invasive Vagus Nerve Stimulation: Results from a Randomized, Sham-Controlled, Crossover Study in Healthy Subjects

Objective: The vagus nerve constitutes the main component of the parasympathetic nervous system and plays an important role in the regulation of neuro-immune responses. Invasive stimulation of the vagus nerve produces anti-inflammatory effects; however, data on humoral immune responses of transcutaneous vagus nerve stimulation (tVNS) are rare. Therefore, the present study investigated changes in serum cytokine concentrations of interleukin-1β (IL-1β), IL-6, IL-8, and tumor necrosis factor α (TNFα) following a short-term, non-invasive stimulation of the vagus nerve. Methods: Whole blood samples were collected before and after a short-lived application of active tVNS at the inner tragus as well as sham stimulation of the earlobe. Cytokine serum concentrations were determined in two healthy cohorts of younger (n = 20) and older participants (n = 19). Differences between active and sham conditions were analyzed using linear mixed models and post hoc F tests after applying Yeo-Johnson power transformations. This trial was part of a larger study registered on ClinicalTrials.gov (NCT05007743). Results: In the young cohort, IL-6 and IL-1β concentrations were significantly increased after active stimulation, whereas they were slightly decreased after sham stimulation (IL-6: p = 0.012; IL-1β: p = 0.012). Likewise, in the older cohort, IL-1β and IL-8 concentrations were significantly elevated after active stimulation and reduced after sham application (IL-8: p = 0.007; IL-1β: p = 0.001). In contrast, circulating TNFα concentrations did not change significantly in either group. Conclusion: Our results show that active tVNS led to an immediate increase in the serum concentrations of certain pro-inflammatory cytokines such as IL-1β, IL-6, and/or IL-8 in two independent cohorts of healthy study participants.

Non-invasive Vagus Nerve Stimulation in Treatment of Disorders of Consciousness - Longitudinal Case Study.

Neuromodulatory electroceuticals such as vagus nerve stimulation have been recently gaining traction as potential rehabilitation tools for disorders of consciousness (DoC). We present a longitudinal case study of non-invasive auricular vagus nerve stimulation (taVNS) in a patient diagnosed with chronic unresponsive wakefulness syndrome (previously known as vegetative state). Over a period of 6 months we applied taVNS daily and regularly evaluated the patient’s behavioral outcomes using Coma Recovery Scale – Revised. We also took electrophysiological measures: resting state electroencephalography (EEG), heart rate (HR) and heart rate variability (HRV). All these methods revealed signs of improvement in the patient’s condition. The total CRS-R scores fluctuated but rose from 4 and 6 at initial stages to the heights of 12 and 13 in the 3rd and 5th month, which would warrant a change in diagnosis to a Minimally Conscious State. Scores obtained in a 2 months follow-up period, though, suggest this may not have been a lasting improvement. Behavioral signs of recovery are triangulated by EEG frequency spectrum profiles with re-emergence of a second oscillatory peak in the alpha range, which has been shown to characterize aware people. However, sustained spontaneous theta oscillations did not predictably diminish, which most likely reflects structural brain damage. ECG measures revealed a steady decrease in pre-stimulation HR combined with an increase in HRV-HR. This suggests a gradual withdrawal of sympathetic and an increase in parasympathetic control of the heart, which the previous literature has also linked with DoC improvements. Together, this study suggests that taVNS stimulation holds promise as a DoC treatment.

Effect of non-invasive vagus nerve stimulation in hemorrhagic brain injury and permanent ischemic stroke in rats (P10-10.005)

Effect of non-invasive vagus nerve stimulation in hemorrhagic brain injury and permanent ischemic stroke in rats (P10-10.005)

The Potential of Invasive and Non-invasive Vagus Nerve Stimulation to Improve Verbal Memory Performance in Epilepsy Patients (P7-8.005)

The Potential of Invasive and Non-invasive Vagus Nerve Stimulation to Improve Verbal Memory Performance in Epilepsy Patients (P7-8.005)

Vagus nerve stimulation for conservative therapy-refractive epilepsy and depression.

Numerous studies confirm that the vagus nerve stimulation (VNS) is an efficient, indirect neuromodulatory therapy with electrically induced current for epilepsy that cannot be treated by epilepsy surgery and is therapy-refractory and for drug therapy-refractory depression. VNS is an established, evidence-based and in the long-term cost-effective therapy in an interdisciplinary overall concept.Long-term data on the safety and tolerance of the method are available despite the heterogeneity of the patient populations. Stimulation-related side effects like hoarseness, paresthesia, cough or dyspnea depend on the stimulation strength and often decrease with continuing therapy duration in the following years. Stimulation-related side effects of VNS can be well influenced by modifying the stimulation parameters. Overall, the invasive vagus nerve stimulation may be considered as a safe and well-tolerated therapy option.For invasive and transcutaneous vagus nerve stimulation, antiepileptic and antidepressant as well as positive cognitive effects could be proven. In contrast to drugs, VNS has no negative effect on cognition. In many cases, an improvement of the quality of life is possible.iVNS therapy has a low probability of complete seizure-freedom in cases of focal and genetically generalized epilepsy. It must be considered as palliative therapy, which means that it does not lead to healing and requires the continuation of specific medication. The functional principle is a general reduction of the neuronal excitability. This effect is achieved by a slow increase of the effectiveness sometimes over several years. Responders are those patients who experience a 50% reduction of the seizure incidence. Some studies even reveal seizure-freedom in 20% of the cases. Currently, it is not possible to differentiate between potential responders and non-responders before therapy/implantation.The current technical developments of the iVNS generators of the new generation like closed-loop system (cardiac-based seizure detection, CBSD) reduce also the risk for SUDEP (sudden unexpected death in epilepsy patients), a very rare, lethal complication of epilepsies, beside the seizure severity.iVNS may deteriorate an existing sleep apnea syndrome and therefore requires possible therapy interruption during nighttime (day-night programming or magnet use) beside the close cooperation with sleep physicians.The evaluation of the numerous iVNS trials of the past two decades showed multiple positive effects on other immunological, cardiological, and gastroenterological diseases so that additional therapy indications may be expected depending on future study results. Currently, the vagus nerve stimulation is in the focus of research in the disciplines of psychology, immunology, cardiology as well as pain and plasticity research with the desired potential of future medical application.Beside invasive vagus nerve stimulation with implantation of an IPG and an electrode, also devices for transdermal and thus non-invasive vagus nerve stimulation have been developed during the last years. According to the data that are currently available, they are less effective with regard to the reduction of the seizure severity and duration in cases of therapy-refractory epilepsy and slightly less effective regarding the improvement of depression symptoms. In this context, studies are missing that confirm high evidence of effectiveness. The same is true for the other indications that have been mentioned like tinnitus, cephalgia, gastrointestinal complaints etc. Another disadvantage of transcutaneous vagus nerve stimulation is that the stimulators have to be applied actively by the patients and are not permanently active, in contrast to implanted iVNS therapy systems. So they are only intermittently active; furthermore, the therapy adherence is uncertain.

Vagus Nerve Stimulation as a Potential Therapy in Early Alzheimer's Disease: A Review.

Cognitive dysfunction in Alzheimer’s disease (AD) is caused by disturbances in neuronal circuits of the brain underpinned by synapse loss, neuronal dysfunction and neuronal death. Amyloid beta and tau protein cause these pathological changes and enhance neuroinflammation, which in turn modifies disease progression and severity. Vagal nerve stimulation (VNS), via activation of the locus coeruleus (LC), results in the release of catecholamines in the hippocampus and neocortex, which can enhance synaptic plasticity and reduce inflammatory signalling. Vagal nerve stimulation has shown promise to enhance cognitive ability in animal models. Research in rodents has shown that VNS can have positive effects on basal synaptic function and synaptic plasticity, tune inflammatory signalling, and limit the accumulation of amyloid plaques. Research in humans with invasive and non-invasive VNS devices has shown promise for the modulation of cognition. However, the direct stimulation of the vagus nerve afforded with the invasive procedure carries surgical risks. In contrast, non-invasive VNS has the potential to be a broadly available therapy to manage cognitive symptoms in early AD, however, the magnitude and specificity of its effects remains to be elucidated, and the non-inferiority of the effects of non-invasive VNS as compared with invasive VNS still needs to be established. Ongoing clinical trials with healthy individuals and patients with early AD will provide valuable information to clarify the potential benefits of non-invasive VNS in cognition and AD. Whether invasive or non-invasive VNS can produce a significant improvement on memory function and whether its effects can modify the progression of AD will require further investigation.

Transcutaneous vagal nerve stimulation protects against stress-induced intestinal barrier dysfunction in healthy adults.

Intestinal barrier dysfunction is the likely initiating event in multiple human diseases. Currently, there are limited therapeutic strategies to address its dysfunction. Animal studies suggest that vagal nerve stimulation may improve intestinal barrier function, but this has not been evaluated in humans. This study aimed to determine the effect of vagal nerve stimulation on intestinal permeability in adults administered a bolus dose of intravenous corticotropin releasing hormone (CRH) which has been shown to increase small intestinal permeability in healthy human subjects. In a cross-over study, 16 volunteers (median age 34years, 11 female) were randomized to receive auricular transcutaneous vagal nerve or sham stimulation (10minutes each side) after intravenous administration of 100µg of CRH. Intestinal barrier function was measured before and 2h after each intervention with dual-sugar urine testing (lactulose:mannitol ratio) and intestinal fatty-acid binding protein (I-FABP). Exposure to CRH increased I-FABP concentrations by a median of 49 (IQR 4-71)% (p = 0.009). Lactulose:mannitol ratios were 0.029 (0.025-0.050) following vagal stimulation compared with 0.062 (0.032-0.170) following sham stimulation (p = 0.0092), representing a fall of 53 (22-71)%. I-FABP concentrations did not change (p = 0.90). Brief non-invasive vagal nerve stimulation consistently reduces paracellular permeability of the small intestine after CRH administration, but does not entirely mitigate I-FABP release from the epithelium. Studies of vagal nerve stimulation in disease states are warranted.

Non-invasive Vagus Nerve Stimulation for COVID-19: Results From a Randomized Controlled Trial (SAVIOR I).

BackgroundSevere coronavirus disease 2019 (COVID-19) is characterized, in part, by an excessive inflammatory response. Evidence from animal and human studies suggests that vagus nerve stimulation can lead to reduced levels of various biomarkers of inflammation. We conducted a prospective randomized controlled study (SAVIOR-I) to assess the feasibility, efficacy, and safety of non-invasive vagus nerve stimulation (nVNS) for the treatment of respiratory symptoms and inflammatory markers among patients who were hospitalized for COVID-19 (ClinicalTrials.gov identifier: NCT04368156).MethodsParticipants were randomly assigned in a 1:1 allocation to receive either the standard of care (SoC) alone or nVNS therapy plus the SoC. The nVNS group received 2 consecutive 2-min doses of nVNS 3 times daily as prophylaxis. Efficacy and safety were evaluated via the incidence of specific clinical events, inflammatory biomarker levels, and the occurrence of adverse events.ResultsOf the 110 participants who were enrolled and randomly assigned, 97 (nVNS, n = 47; SoC, n = 50) had sufficient available data and comprised the evaluable population. C-reactive protein (CRP) levels decreased from baseline to a significantly greater degree in the nVNS group than in the SoC group at day 5 and overall (i.e., all postbaseline data points collected through day 5, combined). Procalcitonin level also showed significantly greater decreases from baseline to day 5 in the nVNS group than in the SoC group. D-dimer levels were decreased from baseline for the nVNS group and increased from baseline for the SoC group at day 5 and overall, although the difference between the treatment groups did not reach statistical significance. No significant treatment differences were seen for clinical respiratory outcomes or any of the other biochemical markers evaluated. No serious nVNS-related adverse events occurred during the study.ConclusionsnVNS therapy led to significant reductions in levels of inflammatory markers, specifically CRP and procalcitonin. Because nVNS has multiple mechanisms of action that may be relevant to COVID-19, additional research into its potential use earlier in the course of COVID-19 and its potential to mitigate some of the symptoms associated with post-acute sequelae of COVID-19 is warranted.

Effects of Noninvasive Cervical Vagal Nerve Stimulation on Cognitive Performance But Not Brain Activation in Healthy Adults

ObjectivesWhile preliminary evidence suggests that noninvasive vagal nerve stimulation (nVNS) may enhance cognition, to our knowledge, no study has directly assessed the effects of nVNS on brain function and cognitive performance in healthy individuals. The aim of this study was therefore to assess whether nVNS enhances complex visuospatial problem solving in a normative sample. Functional magnetic resonance imaging (fMRI) was used to examine underlying neural substrates. Material and MethodsParticipants received transcutaneous cervical nVNS (N = 15) or sham (N = 15) stimulation during a 3 T fMRI scan. Stimulation lasted for 2 min at 24 V for nVNS and at 4.5 V for sham. Subjects completed a matrix reasoning (MR) task in the scanner and a forced-choice recognition task outside the scanner. An analysis of variance (ANOVA) was used to assess group differences in cognitive performance. And linear mixed effects (LMEs) regression analysis was used to assess main and interaction effects of experimental groups, level of MR task difficulty, and recall accuracy on changes in blood oxygen level-dependent (BOLD) signal. ResultsSubjects who received nVNS showed higher accuracy for both easy (p = 0.017) and hard (p = 0.013) items of the MR task, slower reaction times for hard items (p = 0.014), and fewer false negative errors during the forced-choice recognition task (p = 0.047). MR task difficulty related to increased activation in frontoparietal regions (p < 0.001). No difference between nVNS and sham stimulation was found on BOLD response during performance of the MR task. ConclusionsWe hypothesize that nVNS increased attention compared to sham, and that this effect led to enhanced executive functions, and consequently to better performance on visuospatial reasoning and recognition tasks. Results provide initial support that nVNS may be a low-risk, low-cost treatment for cognitive disorders.

439 The effect of non-invasive transcutaneous auricular vagus nerve stimulation (taVNS) on hypoxic-ischemic injury in newborn rats

OBJECTIVES/GOALS: Neonatal hypoxic-ischemic encephalopathy (HIE) is an acute neurologic syndrome where decreased blood flow and oxygen to the brain causes acute and chronic brain dysfunction. The only proven neuroprotective intervention for HIE is hypothermia treatment started within 6 hours of birth and 50% of survivors have long-term deficits. METHODS/STUDY POPULATION: Pre-clinical adult stroke studies demonstrated that vagus nerve stimulation (VNS) has anti-inflammatory effects and attenuates brain damage. Transcutaneous auricular VNS (taVNS) is safe and feasible in infants and may improve the motor skill of bottle feeding. We hypothesize that a combined hypothermia-taVNS treatment shortly after HIE birth will have neuroprotective effects, improve motor function, attenuate infarct volume inflammation compared to hypothermia alone. The HIE model includes ligation of the right common carotid artery in postnatal day 7 (P7) rats followed by 90min hypoxia (8% oxygen) and 2hr hypothermia. taVNS or sham taVNS was administered using a bipolar electrode placed on the auricular concha region for 30min, [30sec trains, 0.5msec duration, 20Hz frequency, followed by 4.5min breaks] RESULTS/ANTICIPATED RESULTS: Experimental groups include +HIE/+taVNS, +HIE/-taVNS, and -HIE/-taVNS. To assess motor function, grasping reflex and forelimb grip strength tasks were assessed prior to surgery through P10. Infarct volume was assessed at 72h after injury by staining coronal sections with cresyl-violet. Thirty-four rat pups underwent surgery with an 8.82% mortality rate. taVNS was well tolerated by the P7 rats when delivered below perceptual threshold (0.4-1.1mA). There was no difference in elementary motor function or infarct volume between any group. DISCUSSION/SIGNIFICANCE: Future studies will include 2.5hr hypoxia for a more severe brain injury and a -HIE/+taVNS control group. These initial pre-clinical studies in neonates are important in determining whether taVNS may translate as a treatment to improve outcomes after neonatal HIE.

Network meta-analysis of therapies for cluster headache: Effects of acute therapies for episodic and chronic cluster.

We used network meta-analysis (NMA) to characterize the relative effectiveness and harms of acute treatment options for cluster headache. There are few evidence-based acute treatments available for cluster headache. As most treatments were compared only against placebos in clinical trials, few head-to-head comparisons of treatments are available. An a priori registered scoping review was performed to identify randomized controlled trials evaluating treatments in adult patients (>18years old) with cluster headache per accepted diagnostic criteria. Bayesian NMAs were performed to compare treatments in terms of headache relief at 15 or 30min, and also the occurrence of adverse events. We report odds ratios (ORs) of relative treatment effects along with corresponding 95% credible intervals (CrIs), as well as measures of treatment ranking. A total of 13 randomized controlled trials informed NMAs. We found high flow oxygen to be the most effective therapy for headache response at 15 and 30min (OR 9.0, 95% CrI 5.3 to 15.9 vs. placebo), with injectable sumatriptan demonstrating the next highest effect (OR 6.4, 95% CrI 3.75 to 11.1 vs. placebo). High flow oxygen was also more effective than low flow oxygen (OR 2.55, 95% CrI 1.13 to 5.8), nasal spray zolmitriptan (OR 3.75, 95% CrI 1.72 to 8.4), octreotide (OR 4.5, 95% CrI 1.64 to 12.5), and non-invasive vagal nerve stimulation (nVNS; OR 5.2, 95% CrI 2.29 to 11.9). Sumatriptan injectable was also effective for headache relief and was found to be better than nasal spray zolmitriptan (OR 2.67, 95% CrI 1.21 to 5.9), octreotide (OR 3.20, 95% CrI 1.17 to 8.8), and nVNS (OR 3.69, 95% CrI 1.63 to 8.4). Octreotide (OR 4.1, 95% CrI 1.71 to 10.5) and sumatriptan (OR 2.40, 95% CrI 1.39 to 4.2) were associated with greater risk of adverse events compared to placebo, while other treatments did not demonstrate increased risk. When focusing on patients with episodic cluster headache, nVNS was significantly better than placebo (OR 4.9, 95% CrI 1.89 to 14.1). Our findings suggest that high flow oxygen is more efficacious when compared to low flow oxygen for headache relief. When low flow oxygen fails in patients who can tolerate oxygen, increased flow rates should be tried. Additionally, high flow oxygen is likely more effective than zolmitriptan nasal spray, nVNS, and octreotide. Sumatriptan injectable is more likely to be effective when compared to zolmitriptan nasal spray, octreotide, and nVNS.

Effects of acute and preventive therapies for episodic and chronic cluster headache: A scoping review of the literature.

Cluster headache is the most common primary headache disorder of the trigeminal autonomic cephalalgias, and it is highly disabling. We undertake a scoping review to characterize therapies to prevent and acutely treat cluster headache, characterize trial methodology utilized in studies, and recommend future trial "good practices." We also assess homogeneity of studies and feasibility for future network meta-analyses (NMAs) to compare acute and preventive treatments for cluster headache. A priori protocol for this scoping review was registered and available on Open Science Forum. We sought studies that enrolled adult patients with cluster headache as identified by accepted diagnostic criteria. Both randomized controlled trials (RCTs) and observational studies (with a control group) were included. The interventions of interest were medications, procedures, devices, surgeries, and behavioral/psychological interventions, whereas comparators of interest were placebo, sham, or other active treatments. Outcomes were predefined; however, we did not exclude studies lacking these outcomes. A systemic search was conducted in Ovid Medline, Embase, and Cochrane. We performed a targeted search for conference abstracts from journals prominent in the field. We identified 56 studies: 45 RCTs, four studies only available in clinical trial registries, and seven observational studies. Of the 45 RCTs, 20 focused on acute therapies and 25 on preventive therapies. Overall, we determined that it is feasible to pursue a NMA for acute therapy focusing on 15 or 30-min headache reduction for acute trials, as we identified 11 trials in the combined population of patients with either episodic or chronic cluster headache (2 trials in populations with chronic cluster headache were also found). For preventive therapy of cluster headache, we identified trials with common outcomes that may be considered for NMA, however, as these trials had differences in treatment effect modifiers that could not be corrected, NMAs appear infeasible for this indication. We identified new studies looking at noninvasive vagal nerve stimulation, sphenopalatine ganglion stimulation, prednisone, and oxygen published since the most recent systematic review in the field, although these acute treatments were previously identified as effective. However, for calcitonin gene-related peptide (CGRP) monoclonal antibodies, galcanezumab demonstrated effectiveness in episodic cluster headache, but a lack of effectiveness in chronic cluster headache, and fremanezumab was not effective for episodic nor chronic cluster headache. This finding highlights that CGRP monoclonal antibodies may not show a class effect in cluster headache prevention and need to be considered individually. We describe the treatment landscape of cluster headache for both acute and preventive treatments. Last, we present the NMAs we will undertake in acute therapies of cluster headache.

Non-invasive Vagus Nerve Stimulation in Cerebral Stroke: Current Status and Future Perspectives.

Stroke poses a serious threat to human health and burdens both society and the healthcare system. Standard rehabilitative therapies may not be effective in improving functions after stroke, so alternative strategies are needed. The FDA has approved vagus nerve stimulation (VNS) for the treatment of epilepsy, migraines, and depression. Recent studies have demonstrated that VNS can facilitate the benefits of rehabilitation interventions. VNS coupled with upper limb rehabilitation enhances the recovery of upper limb function in patients with chronic stroke. However, its invasive nature limits its clinical application. Researchers have developed a non-invasive method to stimulate the vagus nerve (non-invasive vagus nerve stimulation, nVNS). It has been suggested that nVNS coupled with rehabilitation could be a promising alternative for improving muscle function in chronic stroke patients. In this article, we review the current researches in preclinical and clinical studies as well as the potential applications of nVNS in stroke. We summarize the parameters, advantages, potential mechanisms, and adverse effects of current nVNS applications, as well as the future challenges and directions for nVNS in cerebral stroke treatment. These studies indicate that nVNS has promising efficacy in reducing stroke volume and attenuating neurological deficits in ischemic stroke models. While more basic and clinical research is required to fully understand its mechanisms of efficacy, especially Phase III trials with a large number of patients, these data suggest that nVNS can be applied easily not only as a possible secondary prophylactic treatment in chronic cerebral stroke, but also as a promising adjunctive treatment in acute cerebral stroke in the near future.

Validation of a new impedance cardiography analysis algorithm for clinical classification of stress states.

Pre-ejection period (PEP) is an index of sympathetic nervous system activity that can be computed from electrocardiogram (ECG) and impedance cardiogram (ICG) signals, but sensitive to speech/motion artifact. We sought to validate an ICG noise removal method, three-stage ensemble-average algorithm (TEA), in data acquired from a clinical trial comparing active versus sham non-invasive vagal nerve stimulation (tcVNS) after standardized speech stress. We first compared TEA's performance versus the standard conventional ensemble-average algorithm (CEA) approach to classify noisy ICG segments. We then analyzed ECG and ICG data to measure PEP and compared group-level differences in stress states with each approach. We evaluated 45 individuals, of whom 23 had post-traumatic stress disorder (PTSD). We found that the TEA approach identified artifact-corrupted beats with intraclass correlation coefficient>0.99 compared to expert adjudication. TEA also resulted in higher group-level differences in PEP between stress states than CEA. PEP values were lower in the speech stress (vs. baseline rest) group using both techniques, but the differences were greater using TEA (12.1ms) than CEA (8.0ms). PEP differences in groups divided by PTSD status and tcVNS (active vs. sham) were also greater when using the TEA versus CEA method, although the magnitude of the differences was lower. In conclusion, TEA helps to accurately identify noisy ICG beats during speaking stress, and this increased accuracy improves sensitivity to group-level differences in stress states compared to CEA, suggesting greater clinical utility.