Posts Tagged Vagus Nerve Stimulation

[ARTICLE] Safety, Feasibility, and Efficacy of Vagus Nerve Stimulation Paired With Upper-Limb Rehabilitation After Ischemic Stroke – Full Text

Abstract

Background and Purpose—Recent animal studies demonstrate that vagus nerve stimulation (VNS) paired with movement induces movement-specific plasticity in motor cortex and improves forelimb function after stroke. We conducted a randomized controlled clinical pilot study of VNS paired with rehabilitation on upper-limb function after ischemic stroke.

Methods—Twenty-one participants with ischemic stroke >6 months before and moderate to severe upper-limb impairment were randomized to VNS plus rehabilitation or rehabilitation alone. Rehabilitation consisted of three 2-hour sessions per week for 6 weeks, each involving >400 movement trials. In the VNS group, movements were paired with 0.5-second VNS. The primary objective was to assess safety and feasibility. Secondary end points included change in upper-limb measures (including the Fugl–Meyer Assessment-Upper Extremity).

Results—Nine participants were randomized to VNS plus rehabilitation and 11 to rehabilitation alone. There were no serious adverse device effects. One patient had transient vocal cord palsy and dysphagia after implantation. Five had minor adverse device effects including nausea and taste disturbance on the evening of therapy. In the intention-to-treat analysis, the change in Fugl–Meyer Assessment-Upper Extremity scores was not significantly different (between-group difference, 5.7 points; 95% confidence interval, −0.4 to 11.8). In the per-protocol analysis, there was a significant difference in change in Fugl–Meyer Assessment-Upper Extremity score (between-group difference, 6.5 points; 95% confidence interval, 0.4 to 12.6).

Conclusions—This study suggests that VNS paired with rehabilitation is feasible and has not raised safety concerns. Additional studies of VNS in adults with chronic stroke will now be performed.

Introduction

Arm weakness is common after stroke, and its treatment is recognized as an area of considerable need.1 Approximately 85% of patients with stroke present with arm weakness,2 and 60% of stroke survivors with nonfunctional arms at 1 week do not recover function by 6 months.3Current treatment for arm weakness typically comprises intensive, task-specific, and repetitive rehabilitative interventions or occasionally methods such as constraint-induced movement therapy and electric neurostimulation.4 A recent meta-analysis and large-scale trials show the effects of current treatments for arm weakness to be modest.5,6 Novel and more effective treatments are needed. Improvement in arm function should improve quality of life for stroke survivors, reduce comorbidities associated with loss of independence, and reduce cost to the healthcare system.7

Intensive training has been shown to facilitate a range of neuroplastic brain events.8 It is possible that augmentation of neuroplasticity to promote reorganization of neural networks is required to more fully recover motor function.9 However, no practical and effective method exists to achieve this and even if such changes occur, it is unclear whether they are clinically meaningful or long term. This study is a preliminary investigation of an intervention designed to promote specific neuroplasticity; vagus nerve stimulation (VNS) paired with movement to drive task-specific plasticity in the motor cortex.1012 VNS activates neurons in the basal forebrain and locus coeruleus and results in release of acetylcholine and norepinephrine, respectively, which are known to facilitate reorganization of cortical networks.13 We recently demonstrated in a rat model of ischemic stroke that pairing forelimb rehabilitation with VNS significantly increases recovery of forelimb speed and strength when compared with rehabilitation alone.14,15 Our subsequent studies demonstrated that VNS paired with rehabilitative training also improves recovery in a rat model of intracerebral hemorrhage,16 and that precise timing of VNS with specific motor movements yields optimal recovery.17

We hypothesize that VNS paired with upper-limb rehabilitation therapy will result in greater recovery of arm function than rehabilitation alone in adults with chronic ischemic stroke. We performed the first-in-human evaluation of VNS paired with upper-limb rehabilitation after ischemic stroke. The main objective of the study was to evaluate the safety and feasibility of paired VNS therapy after stroke and to provide clinical data for sample size calculations for larger studies. […]

 

Continue —> Safety, Feasibility, and Efficacy of Vagus Nerve Stimulation Paired With Upper-Limb Rehabilitation After Ischemic Stroke | Stroke

Figure 1. Schematic of vagus nerve stimulation device use in a typical therapy session.

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[ARTICLE] Transcutaneous Vagus Nerve Stimulation Combined with Robotic Rehabilitation Improves Upper Limb Function after Stroke – Full Text

Abstract

The efficacy of standard rehabilitative therapy for improving upper limb functions after stroke is limited; thus, alternative strategies are needed. Vagus nerve stimulation (VNS) paired with rehabilitation is a promising approach, but the invasiveness of this technique limits its clinical application. Recently, a noninvasive method to stimulate vagus nerve has been developed. The aim of the present study was to explore whether noninvasive VNS combined with robotic rehabilitation can enhance upper limb functionality in chronic stroke. Safety and efficacy of this combination have been assessed within a proof-of-principle, double-blind, semirandomized, sham-controlled trial. Fourteen patients with either ischemic or haemorrhagic chronic stroke were randomized to robot-assisted therapy associated with real or sham VNS, delivered for 10 working days. Efficacy was evaluated by change in upper extremity Fugl–Meyer score. After intervention, there were no adverse events and Fugl–Meyer scores were significantly better in the real group compared to the sham group. Our pilot study confirms that VNS is feasible in stroke patients and can produce a slight clinical improvement in association to robotic rehabilitation. Compared to traditional stimulation, noninvasive VNS seems to be safer and more tolerable. Further studies are needed to confirm the efficacy of this innovative approach.

1. Introduction

Upper limb impairment is a common consequence of stroke with a deep impact on patient’s quality of life. Since the efficacy of standard rehabilitative therapy is limited, alternative strategies are needed. Robot-assisted rehabilitation can be useful in stroke patients because it allows an intensive as well as task-specific training characterized by high repetition of movements in a strongly motivating environment [13]. Several studies have explored the possibility to potentiate the effect of robotic therapy by the association with noninvasive human brain stimulation techniques, such as repetitive transcranial magnetic stimulation (rTMS), that can induce neuroplasticity via long-term potentiation-/depression- (LTP-/LTD-) like phenomena [4]. Although intriguing, the evidence in support of this strategy remains low [56]. Indeed, the literature analysis of the published data seems to demonstrate that the association of rTMS with robotic training has the same clinical gain derived from robotic therapy alone. Moreover, rTMS is contraindicated in patients who suffered from haemorrhagic stroke for the risk of inducing seizures [7]. For these reasons, there is great interest in the development of alternative techniques of neuromodulation that can foster the effect of robotic therapy.

Vagus nerve stimulation (VNS) is approved as adjunctive treatment for refractory epilepsy and depression but is currently under investigation for a wide range of neurological diseases [8]. In particular, recent studies have demonstrated that VNS paired with rehabilitation significantly improves forelimb strength and movement speed in rat models of ischemic [9] and haemorrhagic stroke [10]. VNS is believed to enhance the benefits of rehabilitation by promoting neuroplasticity [11]. Preliminary data [12] have showed that such approach is also feasible in patients; however, the diffusion of this technique is limited by its invasiveness. Indeed, VNS requires the surgical implantation of a stimulator of the cervical branch of the vagus nerve. Recently, it has been proposed a noninvasive technique that consists of transcutaneous stimulation of the vagus nerve (tVNS) in external auditory channel at the inner side of the tragus. Both neuroimaging [13] and neurophysiological [14] studies have demonstrated that the effect of tVNS on brain activity is quite similar to the effect induced by traditional, invasive VNS.

The aim of the present study was to explore whether tVNS can enhance the benefit induced by robotic rehabilitation on motor function of the upper limb in chronic stroke. Safety and efficacy of this combination have been assessed within a proof-of-principle, double-blind, semirandomized, sham-controlled trial. […]

Continue —> Transcutaneous Vagus Nerve Stimulation Combined with Robotic Rehabilitation Improves Upper Limb Function after Stroke

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[WEB SITE] Rates and Predictors of Seizure Freedom With Vagus Nerve Stimulation for Intractable Epilepsy – NEUROSURGERY Report

Abstract

BACKGROUND: Neuromodulation-based treatments have become increasingly important in epilepsy treatment. Most patients with epilepsy treated with neuromodulation do not achieve complete seizure freedom, and, therefore, previous studies of vagus nerve stimulation (VNS) therapy have focused instead on reduction of seizure frequency as a measure of treatment response.

OBJECTIVE: To elucidate rates and predictors of seizure freedom with VNS.

METHODS: We examined 5554 patients from the VNS therapy Patient Outcome Registry, and also performed a systematic review of the literature including 2869 patients across 78 studies.

RESULTS: Registry data revealed a progressive increase over time in seizure freedom after VNS therapy. Overall, 49% of patients responded to VNS therapy 0 to 4 months after implantation (≥50% reduction seizure frequency), with 5.1% of patients becoming seizure-free, while 63% of patients were responders at 24 to 48 months, with 8.2% achieving seizure freedom. On multivariate analysis, seizure freedom was predicted by age of epilepsy onset >12 years (odds ratio [OR], 1.89; 95% confidence interval [CI], 1.38-2.58), and predominantly generalized seizure type (OR, 1.36; 95% CI, 1.01-1.82), while overall response to VNS was predicted by nonlesional epilepsy (OR, 1.38; 95% CI, 1.06-1.81). Systematic literature review results were consistent with the registry analysis: At 0 to 4 months, 40.0% of patients had responded to VNS, with 2.6% becoming seizure-free, while at last follow-up, 60.1% of individuals were responders, with 8.0% achieving seizure freedom.

CONCLUSION: Response and seizure freedom rates increase over time with VNS therapy, although complete seizure freedom is achieved in a small percentage of patients.

Source: Open Access: Rates and Predictors of Seizure Freedom With Vagus Nerve Stimulation for Intractable Epilepsy | NEUROSURGERY Report

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[ARTICLE] Rates and Predictors of Seizure Freedom With Vagus Nerve Stimulation for Intractable Epilepsy – Full Text

Abstract

BACKGROUND: Neuromodulation-based treatments have become increasingly important in epilepsy treatment. Most patients with epilepsy treated with neuromodulation do not achieve complete seizure freedom, and, therefore, previous studies of vagus nerve stimulation (VNS) therapy have focused instead on reduction of seizure frequency as a measure of treatment response.

OBJECTIVE: To elucidate rates and predictors of seizure freedom with VNS.

METHODS: We examined 5554 patients from the VNS therapy Patient Outcome Registry, and also performed a systematic review of the literature including 2869 patients across 78 studies.

RESULTS: Registry data revealed a progressive increase over time in seizure freedom after VNS therapy. Overall, 49% of patients responded to VNS therapy 0 to 4 months after implantation (≥50% reduction seizure frequency), with 5.1% of patients becoming seizure-free, while 63% of patients were responders at 24 to 48 months, with 8.2% achieving seizure freedom. On multivariate analysis, seizure freedom was predicted by age of epilepsy onset >12 years (odds ratio [OR], 1.89; 95% confidence interval [CI], 1.38-2.58), and predominantly generalized seizure type (OR, 1.36; 95% CI, 1.01-1.82), while overall response to VNS was predicted by nonlesional epilepsy (OR, 1.38; 95% CI, 1.06-1.81). Systematic literature review results were consistent with the registry analysis: At 0 to 4 months, 40.0% of patients had responded to VNS, with 2.6% becoming seizure-free, while at last follow-up, 60.1% of individuals were responders, with 8.0% achieving seizure freedom.

CONCLUSION: Response and seizure freedom rates increase over time with VNS therapy, although complete seizure freedom is achieved in a small percentage of patients.

 

Approximately 1% of the population has epilepsy, and seizures are refractory to antiepileptic drugs (AEDs) in approximately 30% of these individuals.1 Many patients with drug-resistant temporal or extratemporal lobe epilepsy can become seizure-free with surgical resection or ablation, but other patients with epilepsy are not candidates for resection given the presence of primary generalized seizures, nonlocalizable or multifocal seizure onset, or seizure onset from an eloquent brain region.2-5 Treatments based on neuromodulation, such as vagus nerve stimulation (VNS), have, therefore, become an increasingly important part of multimodal epilepsy treatment. VNS therapy was approved by the US Food and Drug Administration in 1997 as an adjunctive therapy for reducing seizures in patients with medically refractory epilepsy, and more than 80 000 patients have received treatment with VNS.6-8 The efficacy of VNS therapy has been evaluated by randomized controlled trials,9,10 retrospective case series,11,12 meta-analysis,13 and registry-based studies.14 These studies show that about 50% to 60% of patients achieve ≥50% reduction in seizure frequency after 2 years of treatment, and response rates increase over time, likely related to neuromodulatory effects with ongoing stimulation.13 Complete seizure freedom, however, is less common with VNS therapy and other neuromodulation treatment modalities.

Given that a minority of patients achieve seizure freedom with VNS, rates and predictors of seizure freedom have not been well studied and remain poorly understood. The vast majority of studies that evaluate VNS therapy focus on rate of response over time (defined as ≥50% reduction in seizures) and predictors of response; there has never been a large-scale evaluation of seizure freedom as a primary end point in patients treated with VNS. However, seizure freedom is the single best predictor of quality of life in patients with epilepsy,15,16 and therefore a better understanding of seizure freedom rates and predictors in patients treated with VNS therapy is critically needed. Importantly, this information may lead to improved patient selection and counseling in the treatment of drug-resistant epilepsy.

Here, we provide the first large-scale study of VNS therapy with a primary goal of defining seizure freedom rates and predictors, and comparing predictors of seizure freedom with those of overall response to treatment. Our study includes univariate and multivariate analyses of registry data including 5554 patients treated with VNS, and also includes a systematic review of the literature including 2869 patients across 78 studies, to help confirm registry-based results.

Continue —> Rates and Predictors of Seizure Freedom With Vagus Nerve Sti… : Neurosurgery

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[ARTICLE] Vagus nerve stimulation delivered with motor training enhances recovery of function after traumatic brain injury

ABSTRACT

Traumatic Brain Injury (TBI) is one of the largest health problems in the United States, and affects nearly two million people every year. The effects of TBI, including weakness and loss of coordination, can be debilitating and last years after the initial injury. Recovery of motor function is often incomplete. We have developed a method using electrical stimulation of the vagus nerve paired with forelimb use by which we have demonstrated enhanced recovery from ischemic and hemorrhagic stroke. Here we have tested the hypothesis that vagus nerve stimulation (VNS) paired with physical rehabilitation could enhance functional recovery after TBI. We trained rats to pull on a handle to receive a food reward. Following training, they received a controlled-cortical impact (CCI) in the forelimb area of motor cortex opposite the trained forelimb, and were then randomized into two treatment groups. One group of animals received vagus nerve stimulation (VNS) paired with rehabilitative therapy, while another group received rehabilitative therapy without VNS. Following CCI, volitional forelimb strength and task success rate in all animals were significantly reduced. VNS paired with rehabilitative therapy over a period of five weeks significantly increased recovery of both forelimb strength and hit rate on the isometric pull task compared to rehabilitative training without VNS. No significant improvement was observed in the Rehab group. Our findings indicate that VNS paired with rehabilitative therapy enhances functional motor recovery after TBI.

via Vagus nerve stimulation delivered with motor training enhances recovery of function after traumatic brain injury | Abstract.

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[WEB SITE] Bioengineering Professor Recognized for Stroke Recovery Research

March 25, 2015

UT Dallas’ Dr. Seth Hays was honored by the American Heart Association with the Robert G. Siekert New Investigator in Stroke Award recently at the 2015 International Stroke Conference in Nashville, Tenn.

The award, which is presented each year to one outstanding young scientist, encourages new investigators to undertake or continue stroke-related research.

“It is an honor to be recognized by the American Heart Association, an organization with a long tradition of supporting excellent research,” said Hays, an assistant professor of bioengineering in the Erik Jonsson School of Engineering and Computer Science.

Hays’ recent research focuses on developing vagus nerve stimulation (VNS) to improve recovery of motor function after stroke, traumatic brain injury and spinal cord injury, and explaining in detail the mechanisms engaged by VNS to support functional recovery.

VNS is an FDA-approved method for treating various illnesses, such as depression and epilepsy. It involves sending a mild electric pulse through the vagus nerve, which relays information about the state of the body to the brain. Researchers at UT Dallas are studying a novel implementation of VNS to treat neurological disorders.

The association recognized Hays for his paper “Vagus Nerve Stimulation Enhances Neuroplasticity and Forelimb Recovery after Stroke in Aged Rats.” The study, which Hays presented at the conference on Feb. 12, concludes that VNS paired with rehabilitation enhances neuroplasticity — the ability of the brain to change — and functional recovery in post-stroke, aged rats.

“This research project provides additional evidence supporting the ability of VNS to improve recovery after stroke,” he said. “We are now exploring this in greater detail in order to develop this powerful potential therapy.”

Last year, Hays published papers in Stroke, Neuroreport,  Neurorehabilitation & Neural Repair and Brain Research.

Hays received his undergraduate degree in biomedical engineering from The University of Texas at Austin in 2007. In 2012, he completed his PhD in neuroscience at the University of Texas Southwestern Medical Center.

The first postdoctoral research fellow at the UT Dallas Texas Biomedical Device Center, Hays worked under the direction of Dr. Michael Kilgard and Dr. Robert Rennaker.

Rennaker, director of the center and department head of bioengineering, said Hays excelled as a researcher and a colleague during his two years as a fellow, playing a primary role in writing a successful National Institutes of Health research project grant to fund stroke research.

“Dr. Hays is a great example of how UT Dallas will become a top-tier university and develop a pre-eminent bioengineering program,” Rennaker said.

via Bioengineering Professor Recognized for Stroke Recovery Research – News Center – The University of Texas at Dallas.

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[WEB SITE] New treatment for stroke recovery shows early success

Researchers at The University of Texas at Dallas have taken a step toward developing a new treatment to aid the recovery of limb function after strokes.

In a study published online in the journal Neurobiology of Disease, researchers report the full recovery of forelimb strength in animals receiving vagus nerve stimulation…

via New treatment for stroke recovery shows early success – Medical News Today.

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WEB SITE: Vagus Nerve Stimulation (VNS) | Epilepsy Foundation

Vagus nerve stimulation (VNS Therapy®) is designed to prevent seizures by sending regular, mild pulses of electrical energy to the brain via the vagus nerve. These pulses are supplied by a device something like a pacemaker…

Vagus Nerve Stimulation (VNS) | Epilepsy Foundation.

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More Fetal Risks Linked to Epilepsy Drugs

…Fetal exposure to anti-epileptic drugs (AEDs) appears to carry risks beyond those congenital defects currently listed on the products’ labels, a researcher said here…

μέσω More Fetal Risks Linked to Epilepsy Drugs.

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[ARTICLE] Post-traumatic epilepsy: current and emerging treatment options – Full Text PDF or HTML

…Traumatic brain injury (TBI) leads to many undesired problems and complications, including immediate and long-term seizures/epilepsy, changes in mood, behavioral, and personality problems, cognitive and motor deficits, movement disorders, and sleep problems. Clinicians involved in the treatment of patients with acute TBI need to be aware of a number of issues, including the incidence and prevalence of early seizures and post-traumatic epilepsy (PTE), comorbidities associated with seizures and anticonvulsant therapies, and factors that can contribute to their emergence…

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μέσω Post-traumatic epilepsy: current and emerging treatment options | NDT.

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