Vagus nerve stimulation

Vagus nerve stimulation or vagal nerve stimulation or VNS is a medical treatment that involves delivering electrical impulses to the vagus nerve via a device that is either implanted or wearable. This VNS device is referred to informally as a "pacemaker for the brain."

The effects of VNS were first observed in the 1880s that massage and compression of the carotid artery in the neck could suppress seizures, an effect attributable to crude, early form of VNS. Currently, VNS is most frequently used as an adjunctive treatment for certain types of intractable epilepsy and treatment-resistant depression.

Transcutaneous Vagus Nerve Stimulation
Transcutaneous Vagus Nerve Stimulation (t-VNS or ta-VNS) is a wearable form of vagus nerve stimulation involving attaching electrodes to a part of the ear daily, and this can be done by patients at home.

Intranasal Mechanical Stimulation
Intranasal mechanical stimulation of the vagus nerve (e.g., using INMEST) is a non-invasive wearable form of vagus nerve stimulation which has been the subject of a small clinical trial in ME/CFS patients who met the Canadian Consensus Criteria. INMEST resulted in an significant improvement in symptoms in moderate and severe ME but no improvement in fatigue.

Surgical VNS
VNS can also be delivered via an implantable device, requiring surgery.

It is possible that paced breathing (e.g., via deep breathing exercise, yoga or aerobic exercise) can also influence brain electrical activity, mediated by VNS arising from the diaphragm.

Uses
While still experimental, researchers are trialing with vagus nerve stimulation as an adjunct therapy on a host of mental health, neurological, and inflammatory illnesses, including anxiety, atrial fibrillation, chronic pain, Crohn's disease, fibromyalgia, heart failure, insomnia and sleep problems, migraines, and many other conditions. Kevin J. Tracey, MD and his research group at The Feinstein Institute for Medical Research have shown that vagus nerve stimulation has decreased inflammation in methotrexate-resistant rheumatoid arthritis patients.

Mechanisms
The vagus nerve can inhibit cytokine release, via release of the neurotransmitter acetylcholine and thereby prevent tissue injury and death. In research studies, stimulation of the vagus nerve prevents the damaging effects of cytokine release in experimental sepsis, endotoxemia, ischemia/reperfusion injury, hemorrhagic shock, arthritis, and other inflammatory syndromes.

News and articles

 * 2016, Electronic implant in 'Spock' nerve could reverse rheumatoid arthritis The Telegraph.
 * 2016, Vagus Nerve Stimulation, Fibromyalgia and Chronic Fatigue Syndrome (ME/CFS) Health Rising.
 * 2014, Can the Nervous System Be Hacked? The New York Times.

Notable studies

 * 2020, Achieving symptom relief in patients with Myalgic encephalomyelitis by targeting the neuro-immune interface and inducing disease tolerance -
 * 2020, Effect of Transcutaneous Vagus Nerve Stimulation at Auricular Concha for Insomnia: A Randomized Clinical Trial - (Full text)