Stimulation of the vagus nerve in the left cervical region is an FDA-approved technique for treating epilepsy. Approximately 30,000 people have VNS devices implanted for seizure control. In 1998, BSL researchers at MUSC were the first in the world to implant VNS devices in patients with major depression who had not adequately responded to traditional antidepressants. This multi-site open-label clinical trial showed promising results. The BSL recently completed enrollment in a followup multi-site double-blind clinical trial of VNS in refractory depression.
In many ways the VNS device is similar to a cardiac pacemaker. A subcutaneous, battery operated, generator is implanted under the skin over the left chest wall and is attached to an electrode tunneled under the skin, wrapping around the nerve and stimulating an important organ. The electrode is wrapped around the left vagus nerve in the neck. VNS implantation is usually an outpatient procedure in the United States typically preformed by neurosurgeons. The battery in the device generates an intermittent electrical stimulation that is delivered to the vagus nerve. Clinicians following the patient control the frequency and intensity of the stimulation. Adjustments to the stimulation parameters are transmitted from a computer to the VNS device by a handheld infrared wand placed over the device (Higgins & George, 2009).
We offer VNS as a treatment for depression through our Brain Stimulation Clinical Service. In addition, there are occasional VNS studies at MUSC for patients who are interested. These involve assessing quality of life, participating in a national registry, or determining whether VNS modulation of your pain threshold might help determine optimum dosing.