Posts Tagged Vagus nerve

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

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.

Clinical Trial Registration—URL: https://www.clinicaltrials.gov. Unique identifier: NCT01669161.

Source: Safety, Feasibility, and Efficacy of Vagus Nerve Stimulation Paired With Upper-Limb Rehabilitation After Ischemic Stroke

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[WEB SITE] New Device to Control Seizures Offered Regionally Only at Albany Med

06/10/2015 21:12:00ALBANY, N.Y.

— Albany Medical Center is offering a new device designed to help control seizures in patients with epilepsy by detecting a sudden increase in heartrate.

The AspireSR ,vagal nerve stimulator, similar to a pacemaker, is implanted under the skin in the chest. When the device detects a sudden increase in heart rate, which accompanies the early stage of a seizure, it attempts to electrically interrupt the seizure before the patient loses consciousness by sending an electrical impulse through a small wire connecting the device to the vagus nerve.

While vagus nerve stimulation has been a common treatment for epileptic seizures since the late 1990s, Albany Med neurologist Anthony Ritaccio, M.D., ’84 says the AspireSR device has a better ability to detect and treat seizures before they occur.

“Previous models of vagus nerve stimulators required patient action to trigger an electrical impulse to the brain once the seizure had already begun,” said Ritaccio, director of Albany Med’s Epilepsy and Human Brain Mapping Program and J. Spencer Standish professor of neurology and neurosurgery at Albany Medical College. “The AspireSR has the ability to detect a seizure before it has begun, even while a patient is asleep. Our hope is that this will significantly decrease the number of seizures our patients experience and improve their quality of life.”

“We are pleased to be able to offer a minimally invasive option to both our adult and pediatric patients who do not respond well to medication and who are not candidates for brain surgery,” said Matthew Adamo, M.D., associate professor of neurosurgery at Albany Med.

AspireSR was FDA approved in June. Albany Med performed its first surgery with the device in early July and has implanted five devices to date. The epilepsy program expects to implant 30-40 devices per year.

The device is only implantable at Level 4 epilepsy centers such as Albany Medical Center. A Level 4 rating from the National Association of Epilepsy Centers indicates a center offers the most advanced medical and surgical treatment options for epilepsy.

Albany Med’s Epilepsy and Human Brain Mapping Program, which is part of the Neurosciences Institute, evaluates more than 350 patients each year in its inpatient epilepsy monitoring unit (EMU). The EMU offers the most technologically sophisticated monitoring experience available, including wireless brainwave recording. Brain mapping techniques are used to locate areas of the brain important for language, memory and movement to safely guide surgical tissue removal in order to stop the seizures.

To learn more about Albany Med’s epilepsy program and how our neurologists and neurosurgeons have helped patients overcome epilepsy, visit http://www.amc.edu/neuro.

Albany Medical Center, northeastern New York’s only academic health sciences center, is one of the largest private employers in the Capital Region. It incorporates the 734-bed Albany Medical Center Hospital, which offers the widest range of medical and surgical services in the region, and the Albany Medical College, which trains the next generation of doctors, scientists and other health care professionals, and also includes a biomedical research enterprise and the region’s largest physicians practice with more than 450 doctors. Albany Medical Center works with dozens of community partners to improve the region’s health and quality of life. For more information: http://www.amc.edu or http://www.facebook.com/albanymedicalcenter.

Source: Health News – New Device to Control Seizures Offered Regionally Only at Albany Med

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[WEB SITE] UTSW testing whether implant device can help restore lost arm function after stroke

07/05/2015 09:59:00

DALLAS – UT Southwestern Medical Center will be one of three national sites to pioneer U.S. testing for an implant device that stimulates the vagus nerve in stroke patients to see whether it can help restore lost arm function.

Physical therapy instructor Staci Shearin, left, works with Maria Ramirez to improve functional abilities in her right arm after her stroke. New research at UT Southwestern is evaluating stimulation of the vagus nerve as a way to help restore lost arm function.

The Vivistim® System device, developed by Dallas-based MicroTransponder Inc. with a license from UT Dallas, stimulates the neck’s vagus nerve, a key nerve stretching from the medulla oblongata in the brain down to the throat, larynx, trachea, lungs, heart, esophagus, and intestinal tract. Implanted under the collarbone, the device, which is about the size of a pacemaker, sends painless, half-second electrical pulses up the vagus nerve, causing chemicals called neuromodulators to be released in various parts of the brain. Alternate forms of vagus nerve stimulation therapy already are approved for use in the U.S. by the Federal Drug Administration for treating other illnesses, including depression and epilepsy.

“These neuromodulators appear to facilitate the creation of new neuron pathways in the brain, which play a key role in restoring muscle movement,” said Dr. Ty Shang, Assistant Professor of Neurology and Neurotherapeutics at UT Southwestern, who is heading the UT Southwestern arm of the trial. UT Southwestern is one of three sites in the nation.

“A stroke deprives brain cells of oxygen,” said Dr. Shang, a vascular neurologist who is part of UT Southwestern’s stroke team. “Without oxygen, the brain cells die, and can no longer perform the function for which they were intended. There has been no known way to regenerate new brain cells to replace them, but in early tests with this device, the brain appears to ‘rewire’ other cells to perform the function.

The study is sponsored by MicroTransponder Inc. and partially funded by the Texas Biomedical Device Center at UT Dallas. The Vivistim® system, designed to improve motor function in the more involved arm of a person following stroke, was studied starting in 2013 for efficacy and safety in a small study in Glasgow, Scotland. Individuals in the Glasgow study experienced meaningful functional improvements in their more involved arm. Many were able to resume daily activities like swimming, driving, and caring for grandchildren.

more —> Health News – UTSW testing whether implant device can help restore lost arm function after stroke.

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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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