Short-Circuiting Depression with Vagus Nerve Stimulation

Patients with severe depression that doesn't respond to conventional treatments now have a new hope.

(illustration by Cyberonics, Inc.)




As we learned Wednesday, depression can be a serious neurological condition that is often unresponsive to medications and traditional treatments. Vagus nerve stimulation (VNS) therapy has been offered as a treatment for patients who don't respond to other treatments. It was originally discovered in the waning years of the 20th century when many epilepsy patients who had these implanable pacemaker-like devices stimulating their vagus nerve refused to have it removed even when it wasn't improving their epilepsy ... because it did improve their moods. Several clinical studies have pointed to the efficacy of VNS therapy for severe depression when other treatments have failed (the FDA stipulates that at least 4 other types of treatment have failed before it is used). Even though VNS isn't a cure-all (only about 50% of patients who use it respond), for those who it does help, it can be a life-saver, as one patient who testified to the FDA review board of her own volition and at her own expense will say. This patient underwent multiple chemical therapies, and even the dreaded electroconvulsive therapy -- which wiped 20 years of her memory -- yet still lived trapped in a prison of depression and horror until she took part in the clinical study using VNS therapy. Although the studies performed and results obtained wouldn't normally pass the FDA, this patient's testimony, and the relatively trivial side effects (such as inducing a gravelly voice during pulsation) allowed it to slip through.


Although it is not clearly understood how VNS therapy works, it is known that the vagus nerve is one of the primary pathways between the major organs and the brain. The device is much like a pacemaker, but instead of the electrical lead going to the heart, the end of the lead is wrapped around the vagus nerve, providing electrical pulses. The device can be re-programmed or turned off by a magnetic wand that is held over the implantation site.


Electrical stimuli to the vagus nerve transmits electrical pulses to regions of the brain involved in mood regulation, and it is hypothesized that this causes the production or activity of neurotransmitters, including serotonin and norepinephrine.



Explanation of how VNS therapy works from Cyberonics (the company that developed and manufactures the VNS therapy device) -- this is where the video came from :) http://www.vnstherapy.com/depression/whatisvnstherapy/howitworks.asp
News article on VNS therapy.
http://www.wired.com/science/discoveries/news/2007/05/nerve
Article discussing FDA approval of VNS therapy (and another type of therapy) -- includes the full testimony of the patient mentioned in this post ... very touching!
http://www.mcmanweb.com/article-17.htm



Video from http://www.vnstherapy.com/