Implementing Paired VNS with Rehab to Improve Motor Function for Chronic Stroke Patients with Moderate to Severe Upper Extremity Impairment: Chronic Stroke and VNS Therapy
This blog is part 1 of a 3-part series transcription from a recorded webinar with Dr. Gerard Francisco of TIRR Memorial Hermann and Isha Vora, MS, OT R/L of MGH Institute of Health Professions. This webinar highlights how Paired VNS™ Therapy can help improve motor function for chronic stroke patients who have moderate to severe upper extremity impairments.
Chronic Stroke Impairment:
Impairment after stroke is one of the most devastating things that can happen not only to the person with the stroke, but to the family members and loved ones as well. Many people think that the inability to walk is the most troublesome sign and symptom following the stroke, but many stroke survivors will not agree with that. In fact, the impairment in the arm and hand is something that is more meaningful to them than not being able to walk.1 The other thing that is quite sobering for many strokes survivors is realizing that many years after a stroke the impairments can get worse. It is a well-known fact that the impairments last and sometimes are even worse than what they were during the first few years after stroke, yet we are limited with what we can offer.2
Rehabilitation After Stroke:
This is a representation of what happens in rehabilitation after stroke. No matter what we do or do not do, there will be spontaneous neurologic recovery in many people who have had a stroke. It is rare that someone with dense hemiplegia from the start will not have any change at all and the role of rehabilitation and therapy is to augment that recovery.
Conventional therapies usually prevent the onset of some of the complications, such as shortening of the muscle and contractures, which may aggravate the loss of the ability to move the arm and the hand. There are some therapy techniques that may enhance and strengthen this. It has been shown that even in the chronic phases of recovery following a stroke, there is still a chance for neurologic and motor recovery in the right person with the right kind of therapy.
Rehabilitation is not just one type of therapy, there are several types of rehabilitation techniques that can be given and some of them work better during the acute phase or sub-acute phase after stroke, whereas others might work better many years post-stroke. The blue line in the graph above represents a typical recovery of the motor function of many stroke survivors; in the chronic phase some of them continue to improve, while some deteriorate. What’s frustrating is that many stroke survivors typically stop receiving therapies after six months. For many patients, they have been written off either because their recovery has plateaued, or there was nothing else that could be offered.4
This is where vagus nerve simulation comes in. Now we have another device, Vivistim, which when paired with the appropriate type of therapy, may provide some patients with the chance to recover further in the chronic stages many years after the onset of their stroke.
VNS Therapy:
While Vivistim is new, VNS therapy is not—there have been at least two decades worth of safety and efficacy data, not just in stroke, but in other conditions such as recalcitrant epilepsy and depression. The safety and efficacy in those conditions is well-described and is now being applied for motor recovery in chronic strokes survivors.
Based on what has been found in animal studies, the simulation itself will not do the trick alone, it must be paired with movement. Due to the strength of the pivotal study that was published in The Lancet , the FDA approved the use of Vivistim for chronic stroke survivors with moderate to severe upper limb impairment.
The Procedure:
It is a same day outpatient procedure that requires only two small incisions–one in the neck area and the other one in the chest. It is always put in the left vagus nerve because if it is put in the right vagus nerve, then the chances of having cardiac side effects will increase. The side effects reported previously include pain after surgery, hoarseness, bruising, swelling, coughing, and throat irritation, but many of these are self-limited or improved with the appropriate intervention. While it was not observed in the Vivistim studies, infection is always a risk with any implanted device. The full safety information can be found here.
In the pivotal study, the rate of surgery-related adverse events was lower than what has been reported in the epilepsy and depression populations. There was only one subject that had vocal cord paresis that resolved after a few weeks. There were no serious adverse events related to the stimulation itself or due to withholding antiplatelet or anticoagulation therapy during the peri-operative period.5
How It Works:
The vagus nerve stimulation triggers the brain’s attention system through the release of specific neuromodulators. In this case it is acetylcholine and norepinephrine. Acetylcholine is released from the nucleus basalis of Meynert and the norepinephrine from the locus coeruleus. The vagus nerve branches through the lower part of the brain and when triggered, releases these neuromodulators that are important for learning. It is a well-known event that stimulation, along with task-specific motor exercises relevant to the patient’s goals, may help induce motor learning. This has also been shown to result in neuroplasticity and new neuronal connections that bypass the areas damaged by the stroke.6
To learn more about Vivistim’s unique Paired VNS Therapy and how it can help improve motor development after a stroke, contact us and we will connect you with a Vivistim representative. We also encourage you to explore the other pages of vivistim.com to find additional information and resources.
Additional Resources:
1. Meyer, S., et al. Functional and motor outcome 5 years after stroke is equivalent to outcome at 2 months: follow-up of the collaborative evaluation of rehabilitation in stroke across Europe. Stroke, 2015; 46(6), 1613-1619.
2. Pollock, A., et al. Interventions for improving upper limb function after stroke. The Cochrane database of systematic reviews, 2014(11), CD010820.
3. Hussain N, et al. Upper Limb Kinematics in Stroke and Healthy Controls Using Target-to-Target Task in Virtual Reality. Front Neurol. 2018;9:300.
4. Hatem SM et al. Rehabilitation of Motor Function after Stroke: A Multiple Systematic Review Focused on Techniques to Stimulate Upper Extremity Recovery. Front Hum Neurosci. 2016 Sep 13;10:442.
5. Liu CY, et al. Vagus Nerve Stimulation Paired with Rehabilitation for Stroke: Implantation Experience from the VNS-REHAB Trial. Journal of Clinical Neuroscience 105 (122-128): 2022.
6. Engineer, N D, et al. Targeted Vagus Nerve Stimulation for Rehabilitation After Stroke. Frontiers in neuroscience. 2019; 13, 280.
The MicroTransponder® Vivistim® Paired VNS™ System is intended to be used to stimulate the vagus nerve during rehabilitation therapy in order to reduce upper extremity motor deficits and improve motor function in chronic ischemic stroke patients with moderate to severe arm impairment. Do not use if you have had a bilateral or left cervical vagotomy. Risks may include, but are not limited to pain after surgery, hoarseness, bruising, swelling, coughing and throat irritation. Infection leading to explant is a risk associated with any device surgery. For full safety information, please see www.vivistim.com/safety. Individual results may vary.
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