The study of vagus nerve stimulation (VNS) has come a long way since its early stages, progressing from rudimentary observations to sophisticated therapeutic applications.

The importance of the vagus nerve was first recognized in the 19th century. German physician Friedrich Goltz observed that heart rate could be slowed by stimulating the vagus nerve, a discovery that was later developed by physiologist Otto Loewi in the early 20th century. Loewi’s work, which demonstrated that the vagus nerve released a substance he named ‘Vagusstoff’ (later identified as acetylcholine) to slow the heart, won him the Nobel Prize in Medicine in 1936.

The idea of using vagus nerve stimulation as a treatment for health conditions originated in the late 20th century. In 1985, a team led by Jacob Zabara found that VNS could prevent or reduce the severity of seizures in dogs, opening up a new avenue for epilepsy treatment.The development of VNS as a therapy moved quickly. By 1997, the US Food and Drug Administration (FDA) had approved a VNS device for treating epilepsy. This device, made by Cyberonics (now LivaNova), was implanted in the chest and sent regular electrical impulses to the vagus nerve via a lead in the neck.

In the early 2000s, researchers began to explore the potential use of VNS in treating psychiatric conditions. After several studies showed positive effects, the FDA approved VNS therapy for treatment-resistant depression in 2005.The potential applications for VNS continued to expand, with researchers investigating its use for a variety of conditions, such as chronic pain, obesity, migraines, and even Alzheimer’s disease. Many of these studies are still ongoing.

More recent research has focused on non-invasive VNS methods. These include transcutaneous VNS, which stimulates the vagus nerve through the skin, and transcranial VNS, which uses magnetic fields to stimulate the nerve.In the 2020s, companies like the ultrasound neuromodulation company behind the Zenbud began exploring ultrasound technology as a means of stimulating the vagus nerve. This non-invasive approach avoids the need for surgical implantation and can be administered more easily and comfortably.

From its early discovery in the 19th century to the innovative, non-invasive technologies of today, vagus nerve stimulation has a rich history rooted in curiosity, scientific ingenuity, and a dedication to improving human health. As we continue to unravel the intricacies of the vagus nerve and the autonomic nervous system, the possibilities for VNS therapy continue to expand.