Stimulation of the vagus nerve, a nerve that connects many of the body’s organs to the brain, has the potential to treat a variety of conditions, including drug-resistant epilepsy. Accelerating vagus nerve stimulation technology to provide new ways of improving organ function and treating disease is a major focus of the NIH Common Fund’s Stimulating Peripheral Activity to Relieve Conditions (SPARC) Program. An important part of developing vagus nerve stimulation technologies is determining exactly which parts of the nerve are activated when the nerve is stimulated. This allows clinicians to understand the appropriate settings to achieve therapeutic results. A team led by SPARC program researcher Vaughan Macefield, Ph.D., has performed a first-of-its-kind in-human measurement of vagus nerve activity.

Dr. Macefield’s team used a minimally invasive method developed by their lab to guide a sensor to the vagus nerve using ultrasound in two patients. The research team used this sensor to measure which parts of the vagus nerve were activated by stimulation devices that the patients had implanted for epilepsy treatment. This was the first time that researchers have measured these effects in awake patients receiving vagus nerve stimulation therapy in a typical clinical setting. Their measurements showed that the devices activated different parts of the vagus nerve at varying stimulation intensities, suggesting that clinicians could specifically target parts of the vagus nerve that will be most beneficial for disease treatment. These results can directly help scientists determine the optimal settings to use when activating the vagus nerve to treat drug-resistant epilepsy and other nerve-related conditions, while limiting side effects.

Reference: Patros M, Farmer DGS, Moneghetti K, Ottaviani MM, Sivathamboo S, Simpson HD, O'Brien TJ, Macefield VG. First-in-human microelectrode recordings from the vagus nerve during clinical vagus nerve stimulation. Epilepsia Open. 2024 Dec;9(6):2522-2527. doi: 10.1002/epi4.13083.