Posts Tagged VNS

[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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[WEB SITE] Vagus nerve stimulation and upper limb rehabilitation.

The Upper Limb and Stroke

Arm weakness is common after stroke and its treatment is recognised as an area of considerable need.1 Approximately 85% of patients with stroke present with arm weakness2 and 60% of stroke survivors with poorly functioning arms at one week do not recover meaningful function by six months.3 Arm weakness is a major factor contributing to disability following stroke.4Current treatment for arm weakness typically comprises intensive, task-specific and repetitive rehabilitative interventions or occasionally methods such as constraint induced movement therapy and robotic therapy.5 A recent meta-analysis and large-scale trials show the effects of current treatments for arm weakness to be modest.6,7  Improvement in arm function should improve quality of life for stroke survivors, reduce co-morbidities associated with loss of independence, and reduce cost to the health care system.

Neuroplasticity and Recovery

Neuroplasticity is the brain’s ability to form new neural pathways in response to injury or disease. It has been a target for the treatment of many neurological disorders including epilepsy and tinnitus. Recent studies have suggested that augmentation of neuroplasticity is required to more fully recover motor function.9 Novel techniques that drive the growth of new neural pathways related to motor function are needed;  vagus nerve stimulation (VNS) may achieve this.

Vagus Nerve Stimulation

VNS is the delivery of small electrical impulses to the vagus nerve (Figure 1). VNS activates neurons in the basal forebrain and locus coeruleus and results in the release of acetylcholine and norepinephrine. These neurotransmitters are known to facilitate the reorganisation of cortical networks.10 VNS is already used to treat patients with medically refractory epilepsy, with studies showing a reduction in seizure frequency of 50% in 24.5 to 46.6% of patients.11,12,13 In excess of 75,000 patients with refractory epilepsy have been implanted with VNS devices.14  The concept of using VNS to restore normal neuronal activity / drive neuroplasticity is under investigation in other chronic neurological conditions.

In noise induced tinnitus, cochlear trauma can lead to a disorganised auditory cortex resulting in chronic symptoms.15,16,17 The severity of tinnitus is related to the degree of map re-organisation in the auditory cortex.15,16,17  In pre-clinical studies, pairing auditory tones with brief pulses of VNS has been shown to cause re-organisation of auditory cortex maps specific to that tone.18 Further, noise-exposed rats were noted to have a significant reduction in startle response, presumably due to tinnitus, and pairing VNS with multiple tones reversed this effect.18 Thus, VNS paired with a specific stimulus may drive neuroplasticity specifically for that stimulus, thereby restoring auditory cortex architecture and reducing tinnitus. Studies suggest that VNS may help humans with tinnitus.19 Ten patients known to have unilateral or bilateral tinnitus for over a year received four weeks of VNS paired with auditory tone therapy (using MicroTransponder Inc’s Serenity© system). Subjective and objective primary outcome measures were identified in the form of the Tinnitus Handicap Inventory (THI) and the Minimum Masking Level (MML). In patients who had not been taking drugs which could interfere with VNS (muscarinic antagonists, noradrenergic reuptake inhibitors and γ-amino butyric acid agonists), a significant fall in THI of 28.17% was seen following VNS paired with auditory tones.19 Three out of five such patients had a clinically meaningful decrease in THI (44.3% decrease).19 Similar results were seen in the MML test which detects the lowest level of noise required to “drown out” the tinnitus. Results of a recently completed and larger, double blind and randomised study of VNS paired with auditory tones in tinnitus are eagerly awaited. Another study looked at the use of transcutaneous vagus nerve (t-VNS) stimulation in tinnitus. When used in combination with sound therapy t-VNS was found to modulate auditory cortical activation, resulting in reduced tinnitus and tinnitus associated distress.20

Figure 1: © Images copyright of MicroTransponder The stimulation electrodes of the leads are placed on the left vagus nerve in the left carotid sheath, and the lead is then tunnelled subcutaneously to a subcutaneous pocket created in the left pectoral region where it is attached to the pulse generator. A wireless control interface is used to communicate with the VNS device and deliver stimulation during therapy sessions.

Continue —>  Vagus nerve stimulation and upper limb rehabilitation | ACNR | Online Neurology Journal

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[ARTICLE] Vagus nerve stimulation and upper limb rehabilitation – Full Text

The Upper Limb and Stroke

Arm weakness is common after stroke and its treatment is recognised as an area of considerable need.1 Approximately 85% of patients with stroke present with arm weakness2 and 60% of stroke survivors with poorly functioning arms at one week do not recover meaningful function by six months.3 Arm weakness is a major factor contributing to disability following stroke.4Current treatment for arm weakness typically comprises intensive, task-specific and repetitive rehabilitative interventions or occasionally methods such as constraint induced movement therapy and robotic therapy.5 A recent meta-analysis and large-scale trials show the effects of current treatments for arm weakness to be modest.6,7  Improvement in arm function should improve quality of life for stroke survivors, reduce co-morbidities associated with loss of independence, and reduce cost to the health care system.

Neuroplasticity and Recovery

Neuroplasticity is the brain’s ability to form new neural pathways in response to injury or disease. It has been a target for the treatment of many neurological disorders including epilepsy and tinnitus. Recent studies have suggested that augmentation of neuroplasticity is required to more fully recover motor function.9 Novel techniques that drive the growth of new neural pathways related to motor function are needed;  vagus nerve stimulation (VNS) may achieve this.

Continue —> Vagus nerve stimulation and upper limb rehabilitation | ACNR | Online Neurology Journal

Figure 1: © Images copyright of MicroTransponder The stimulation electrodes of the leads are placed on the left vagus nerve in the left carotid sheath, and the lead is then tunnelled subcutaneously to a subcutaneous pocket created in the left pectoral region where it is attached to the pulse generator. A wireless control interface is used to communicate with the VNS device and deliver stimulation during therapy sessions.

 

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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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[POSTER] A Novel Means of Augmenting Motor Recovery After Ischemic Stroke; Vagus Nerve Stimulation (VNS) Paired with Intensive Upper Limb Rehabilitation

…In the ischemic preclinical models of stroke, VNS paired with physical therapy significantly improved outcomes compared to therapy alone. VNS also appears feasible and safe in adults at least 6 months after stroke and further clinical study of its effect on arm function is warranted…

via Abstract T P108: A Novel Means of Augmenting Motor Recovery After Ischemic Stroke; Vagus Nerve Stimulation (VNS) Paired with Intensive Upper Limb Rehabilitation.

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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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