Vagus Nerve Stimulation (VNS) therapy was developed and tested initially to treat patients suffering from epileptic seizures. VNS therapy was approved in the United States in 2005 as an adjunctive, long-term treatment for chronic or recurrent depression for patients 18 years of age or older who are experiencing a major depressive episode and have not had an adequate response to four or more adequate antidepressant treatments.
VNS therapy consists of an implanted pacemaker-like device that delivers mild, intermittently pulsed signals to the patient’s left vagus nerve, which then activates various areas of the brain. Roughly the size of a small pocket watch and weighing less than one ounce, the pulse generator is implanted in the patient’s left chest area. A thin thread-like wire, attached to the generator, runs under the skin to the left vagus nerve in the neck.
The implant procedure typically takes approximately one to two hours. Although the VNS Therapy surgical procedure does not involve the brain, stimulation to the left vagus nerve has been shown to induce widespread bilateral effects in areas of the brain implicated in seizures and mood disorders and responsible for modulation of key neurotransmitters, such as serotonin and norepinephrine.
Using an external dose adjustment system, the stimulation duration, frequency and intensity can be adjusted.
Currently, most health insurance companies do not cover the procedure for depression treatment. This can be a concern, as the VNS device and surgery to implant is expensive.