Non-Invasive Method of Vagus Nerve Stimulation Shows Promise

Vagus nerve in yellow.

Source: Sebastian Kaulitzki/Shutterstock

Stimulating the vagus nerve using a vibrotactile device applied to a specific region of the outer ear reduces inflammatory responses, according to a new series of pilot clinical studies. These findings, “Investigational Treatment of Rheumatoid Arthritis with a Vibrotactile Device Applied to the External Ear,” were published in Bioelectronic Medicine.

For this study, vagus nerve stimulation (VNS) pioneer Kevin Tracey and his team at The Feinstein Institute for Medical Research collaborated with researchers at the Academic Medical Center at the University of Amsterdam.

The goal of these small pilot studies was to test the anti-inflammatory effect of non-invasive vagus nerve stimulation (nVNS) of specific target zones within the outer ear on patients with rheumatoid arthritis and a control group.

The prospect of using bioelectronic devices to hack into the nervous system and treat disease is an exciting new frontier in pharmaceutical-free medicine. Rheumatoid arthritis is a chronic inflammatory disease characterized by stiffness and swelling of joint tissue, which causes both immobility and pain.

Traditional pharmaceutical treatments to reduce inflammation can be costly and are associated with a range of side effects. Billions of dollars are spent annually on anti-rheumatic drugs designed to reduce inflammation in patients with rheumatoid arthritis. Unfortunately, these drugs often present a triple whammy of being expensive, having adverse side effects, and not really helping some patients.

A few years ago, Tracey and his colleagues reported (Koopman et al., 2016) that traditional VNS—using a small surgically-implanted device—inhibited the production of inflammatory cytokines and dramatically reduced inflammation, which improved arthritis symptoms.

For their most recent pilot study, senior author Sangeeta Chavan of the Feinstein Institute and colleagues tested the efficacy of external-ear vagus nerve stimulation using vibrotactile treatment to reduce inflammation and rheumatoid arthritis severity.

Site of application of a vibrotactile device to the cymba concha of the ear. Left: major anatomical landmarks of the external ear (pinna) with an approximate outline of the cymba concha; the cymba concha is a highly-conserved anatomical feature of the external ear that was identified by the device operator. Right: representative device placement of the vibrotactile device in contact with the cymba concha.

Source: Addorisio et al, DOI: 10.1186/s42234-019-0020-4

The researchers found that using a vibrotactile device applied to a region of the external ear called the “cymba concha” inhibited the production of cytokines and reduced the inflammatory responses in rheumatoid arthritis patients.

Interestingly, in a cross-over study of healthy participants who didn’t have arthritis, the researchers found that vibrotactile treatment of the cymba concha region of the ear—but not at the right gastrocnemius muscle (three inches inferiorly and two inches posteriorly from head of the fibula)—significantly inhibited cytokine production.

In a statement, Chavan summed up these findings:

"Our primary objective was to observe if a non-invasive treatment using an external device will be effective in improving disease severity of rheumatoid arthritis that continues to plague more than one million across the country each year. We are pleased to observe that this novel bioelectronic treatment significantly reduces swelling and inflammation associated with rheumatoid arthritis.”

Kevin Tracey concluded, “This clinical research suggests that non-invasive [vagus nerve] stimulation could suppress inflammation in rheumatoid arthritis patients."