Vagus nerve stimulation (VNS) is an invasive medical procedure used as an adjunctive treatment for intractable epilepsy and clinical depression. It is indicated for use as a last chance method, when other treatments have failed to work. VNS has been used to treat epilepsy since 1997. The depression indication was approved by the Food and Drug Administration (FDA) in 2005.

VNS uses an implant that sends tiny electric shocks to the vagus nerve. A connecting wire is run under the skin from the device to the vagus nerve in the left side of the neck. Three small leads are then carefully attached to the nerve. Implantation is usually accomplished within 1 to 2 hours. The mechanism of therapeutic action is unknown. ^**

The FDA's approval of VNS for treatment-resistant depression (TRD) in 2005 remains controversial. According to Dr. A. John Rush, vice chairman for research in the Department of Psychiatry at UT Southwestern Medical Center at Dallas, results of the VNS pilot study showed that 40 percent of the treated patients displayed at least a 50 percent or greater improvement in their condition, according to the Hamilton Depression Rating Scale.^{This finding does not take into account improvements over time in patients without the device. In the only randomized controlled trial VNS failed to perform any better when turned on than in otherwise similar implanted patients whose device was not turned on.*}

The VNS device is made by Cyberonics Inc.

See also

• Brain implant
• Deep brain stimulation
• Neurotechnology
• Transcranial Magnetic Stimulation
• Cranial Electrotherapy Stimulation

References

1. Doctor's Guide: Vagus Nerve Stimulation Successful For Depression
2. Neurology Channel: Vagus Nerve Stimulation
3. FDA Summary of VNS Data
4. Senate Finance Committee Review of VNS Approval
6. FDA-MAUDE Database (Enter "Cyberonics" as search term.)

External links

• VNS: A New Tool for Brain Research and Therapy (PDF file).
• VNSTherapy.com.
• VagusNerveStimulation.com Publisher's website for Out of the Black Hole.
• VNS Message Board - Independent forum where VNS patients share their experiences
• FDA OKs Brain Stimulator for Depression - Comments on vagus nerve stimulation for depression
• Public Citizen petition to the FDA not to approve VNS
• The VNS From A Patient's Point Of View

Surgery | Neurology | Embedded systems | Neuroprosthetics