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.

Methods
VNS can be delivered via an implantable or wearable device. The non-surgical option is called transcutaneous vagus nerve stimulation or t-VNS and is delivered via an electrode clipped onto the ear and attached to a portable impulse-generating device.

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.

Applications
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, 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.

Media coverage

 * 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, Effect of Transcutaneous Vagus Nerve Stimulation at Auricular Concha for Insomnia: A Randomized Clinical Trial - (Full text)