Executive Summary
The vagus nerve is an essential nerve that connects the brain to various vital organs such as the heart, lungs, and digestive tract. Vagus nerve stimulation (VNS) through electrical impulses has been found to have therapeutic benefits for a range of medical conditions. VNS can be achieved through both invasive and non-invasive stimulation. While invasive VNS has been approved by the FDA for the treatment of epilepsy and depression, the technology also holds promise to treat arthritis. With regards to non-invasive VNS technology, it has been approved for the treatment of migraines and has also been used to treat chronic pain conditions, anxiety disorders, and heart failure with positive outcomes. This white paper provides an overview of the vagus nerve’s functions and benefits and highlights the potential of VNS as a therapy for various medical conditions.
Introduction
The vagus nerve is one of the most critical nerves in the body, connecting the brain to many vital organs, including the heart, lungs, and digestive tract. The word “vagus” means wandering in Latin which is appropriate as It is the longest of the cranial nerves. Although it is often referred to as singular, it’s actually a pair of nerves that emerge from the right and left side of the brainstem and carry signals from the brain to the rest of the body and vice versa using both afferent sensory fibers relaying information to the brain and efferent nerves relaying information to the organs.
Vagus nerve stimulation (VNS) has been found to have therapeutic benefits for a range of medical conditions, including depression, pain, and inflammatory diseases. This whitepaper will explore the functions and benefits of stimulating the vagus nerve.
Function of the Vagus Nerve
The vagus nerve is responsible for balancing many of the body’s essential functions, including digestion, breathing, and heart rate. It also plays a crucial role in controlling the parasympathetic nervous system, which is responsible for calming the body and reducing stress levels. The nerve helps to regulate the release of hormones and cytokines, which are involved in the body’s immune response. It also helps to regulate inflammation and can modulate the release of neurotransmitters such as dopamine and serotonin, which are involved in mood regulation.
The afferent section is responsible for carrying sensory information from the peripheral organs and tissues to the central nervous system. This section of the nerve contains specialized nerve fibers that detect and transmit information about various physiological parameters, including blood pressure, heart rate, respiration, and digestion.
The efferent section is responsible for carrying motor information from the central nervous system to the peripheral organs and tissues. It is also responsible for regulating various involuntary muscles, including the muscles of the digestive system, the respiratory system, and the cardiovascular system. It helps to regulate blood pressure, heart rate, and respiratory rate, ensuring that the body functions efficiently.
Benefits of Stimulating the Vagus Nerve
Vagus nerve stimulation (VNS) is a therapeutic approach that involves the use of electrical impulses delivered to the vagus nerve to treat a variety of medical conditions. VNS can be achieved through both invasive and non-invasive stimulation.
Invasive VNS:
Invasive VNS involves the surgical implantation of a device that delivers electrical impulses to the vagus nerve. The device is typically implanted in the chest and is connected to the nerve via a wire that runs under the skin. Invasive VNS has been approved by the US Food and Drug Administration (FDA) for the treatment of several medical conditions. The following are some examples of some applications of invasive VNS.
Epilepsy:
Invasive VNS has been approved by the FDA as a treatment for drug-resistant epilepsy. The device delivers electrical impulses to the vagus nerve, which is thought to reduce the frequency and intensity of seizures by modulating the activity of the brain. In clinical trials, invasive VNS has been shown to be effective in reducing the number of seizures in patients with drugresistant epilepsy.1
Depression:
Invasive VNS has been approved by the FDA as a treatment for depression. The device delivers electrical impulses to the vagus nerve, which is believed to increase the activity of the neurotransmitter serotonin, a chemical that plays a role in regulating mood. Clinical trials have shown that invasive VNS can be effective in improving symptoms of depression in patients who have not responded to other treatments such as medication or therapy.2
Arthritis:
Arthritis is a chronic condition that is characterized by inflammation and pain in the joints. There are many different types of arthritis, but two of the most common are rheumatoid arthritis (RA) and osteoarthritis (OA). While there is still ongoing research on the use of VNS for arthritis, there is evidence to suggest that it may be a beneficial therapy for people with this condition. Studies have shown that VNS can reduce inflammation and pain in the joints, and increase the production of regulatory T cells, which can help to control the immune response and prevent inflammation.3
Non-invasive VNS:
Non-invasive VNS involves the use of external devices to stimulate the vagus nerve, without the need for surgical implantation. Non-invasive VNS typically delivers electrical signals that penetrate the skin and underlying soft tissues to reach the vagus nerve directly and has been proven to safely and effectively stimulate the vagus nerve for the following representative applications.
Migraines:
Non-invasive VNS has been granted FDA approval as an effective treatment for migraines. One example stimulation involves placing electrodes on the skin over the vagus nerve in the neck and delivering electrical impulses to the nerve. Several studies have shown that it can be effective in reducing the frequency and severity of migraines in some patients.4
Chronic Pain:
Non-invasive VNS has been used to treat chronic pain conditions such as fibromyalgia and neuropathic pain. Stimulation involves placing electrodes on the skin over the affected area and delivering electrical impulses to the nerves. Studies have shown that VNS can be effective in reducing pain and improving quality of life in some patients with chronic pain.5
Anxiety Disorders:
Non-invasive VNS has been studied as a potential treatment for anxiety disorders, such as generalized anxiety disorder and panic disorder. Several studies have shown that VNS can be effective in reducing symptoms of anxiety in some patients.6
Heart Failure:
Non-invasive VNS has been studied as a potential treatment for heart failure, a condition in which the heart is unable to pump enough blood to meet the body’s needs. VNS was found to be effective in reducing blood pressure in patients with hypertension. Patients received noninvasive VNS therapy, which involved the use of a device that delivered electrical impulses to the ear. The researchers found that VNS led to a significant reduction in both systolic and diastolic blood pressure.7
Conclusion
Vagus nerve stimulation is a promising therapeutic approach for several medical conditions, including epilepsy, depression, migraines, and cardiovascular issues and inflammatory diseases such as chronic pain. While the exact mechanism of action is not completely understood, it is believed that VNS has the ability to modulate the activity of the nervous system, leading to improvements in symptoms. It is important to note that VNS is not suitable for everyone, and appropriate discussion is recommended of alternate potential therapies with a healthcare provider based upon individual needs and circumstances.
Researchers and scientists are continuously exploring new and innovative ways to stimulate the vagus nerve for the treatment of a wide range of conditions. Future possibilities include continued research and development on non-invasive VNS but also targeted VNS, VNS for neurodegenerative diseases, autoimmune diseases, mental health, obesity, and diabetes. With further research and development, VNS has the potential to not only revolutionize the treatment of many conditions but also to improve the lives of millions of people.
- Toffa, D. H., Touma, L., El Meskine, T., Bouthillier, A., & Nguyen, D. K. (2020). Learnings from 30 years of reported efficacy and safety of vagus nerve stimulation (VNS) for epilepsy treatment: a critical review. Seizure, 83, 104-123.
- Cristancho, P., Cristancho, M. A., Baltuch, G. H., Thase, M. E., & John, P. O. (2011). Effectiveness and safety of vagus nerve stimulation for severe treatment-resistant major depression in clinical practice after FDA approval: outcomes at 1 year. The Journal of clinical psychiatry, 72(10), 5594.
- Genovese, M. C., Gaylis, N. B., Sikes, D., Kivitz, A., Horowitz, D. L., Peterfy, C., … & Chernoff, D. (2020). Safety and efficacy of neurostimulation with a miniaturised vagus nerve stimulation device in patients with multidrugrefractory rheumatoid arthritis: a two-stage multicentre, randomised pilot study. The lancet rheumatology, 2(9), e527-e538.
- Vukovic Cvetkovic, V., & Jensen, R. H. (2019). Neurostimulation for the treatment of chronic migraine and cluster headache. Acta Neurologica Scandinavica, 139(1), 4-17.
- Molero-Chamizo, A., Nitsche, M. A., Bolz, A., Andújar Barroso, R. T., Alameda Bailén, J. R., García Palomeque, J.
C., & Rivera-Urbina, G. N. (2022). Non-invasive transcutaneous vagus nerve stimulation for the treatment of fibromyalgia symptoms: a study protocol. Brain Sciences, 12(1), 95. - Grolaux, P. J. (2019). Transcutaneous vagus nerve stimulation in private healthcare center: a small-scale
investigation targeting anxiety, irritable bowel syndrome and chronic pain. Journal of Neurology & Neuromedicine, 4(5). - Jiang, Y., Po, S. S., Amil, F., & Dasari, T. W. (2020). Non-invasive low-level tragus stimulation in cardiovascular diseases. Arrhythmia & Electrophysiology Review, 9(1), 40.
