As a first year undergrad student, I remember thinking to myself, about how easy it must be to treat depression and to cure its symptoms with a quick pill. And then, during my second and third years I was frightened out of my socks about the realities of certain types of depression and the brutality of its management though Mannings autobiography. ECT did not go down as a personal favourite.
And now, sitting on the boundary knocking on the iron gates of graduate school, while surfing more blogs than reading, I found the most interesting piece of information about the management of resistant depression from Debs blog (do read her blog for very interesting thoughts and discussions on issues in psychology).
Interestingly this “technique” has been recommended as a treatment for photosensitive epilepsy and epilepsy resulting from head injury (read http://library.thinkquest.org for a discussion about epilepsy and http://www.rch.org.au for a detailed description of the procedure). The procedure itself (as practiced by neurologists) involves the implanting of a devise (about the size of a tape measure) in the upper left area of the chest, by a neurosurgeon under general anaesthesia. A connecting ‘wire’ facilitates the connection of the device to the vagus nerve via three small leads. The whole process takes about 2 hours.
The Vagus Nerve Stimulator (VNS) is not related to brain surgery, although it is a treatment that affects the function of the brain. VNS uses specific stimulation of the vagus nerve to send stimulation to specific parts of the brain that are involved in mood. It is not like Electro-Convulsive Therapy (ECT), a treatment that involves stimulation of the entire brain, results in short term memory loss and sometimes pain. Patients who have used VNS do not feel the stimulation from the stimulator since the vagus nerve does not have the type of nerves that carry pain signals. Nor does VNS interfere with memory loss. Patients having Vagus Nerve Stimulation can continue taking their other medications without worrying about side effects or interactions as well.
The Vagus Nerve Stimulator is a small device implanted under the skin near the collarbone. A wire under the skin connects the device to the vagus nerve in the neck. A physician programs the device to produce weak electrical signals that travel along the vagus nerve to the brain at regular intervals. These intervals ease the symptoms of depression. Five months after it was approved for sale, The VNS treatment for chronic, unresponsive or "resistant depression" is winning favor in the medical and psychological community.
The generator which is programmed to stimulate the nerve at regular intervals. The frequency of the intervals are adjustable via a computer by the physician. If a seizure begins between intervals, the patient activates the stimulator by swiping a magnet over their chest at the location where the device is implanted.
According to neurologychannel.com risks include possible “surgical injury to the vagus nerve, carotid artery, and internal jugular vein”. Further, other side effects such as “coughing, hoarseness, and swallowing difficulties” could result from injury to the vagus nerve. Neurologychannel.com also reports infection, bleeding, and discomfort at the site.
On the brighter side, nearly 50% of the patients had a reduction of seizure frequency or had a less sever onset of seizures. However, some studies did not report any improvement.
But, this procedure may also provide a more humane way to treat chronic or recurrent depression. According to vnstherapy.com this process is a “safe, effective treatment with efficacy that improves over time”. Interestingly Neu, Heuser, Bajbouj (2005) reports VNS does not have an influence on cerebral blood flow velocity in depressive patients. Doraisawamy, et al. (1999) outlined that cerebral hypoperfusion (decreased blood flow through an organ) may explain depression in elderly cardiac patients.
I still cant seem to find out the exact mechanism behind how VNS helps manage depression. Perhaps this may mean that the “scientific” community is still divided on their opinions about the how good VNS is. This may not necessarily be a bad thing. I feel that its truly wonderful to have such giant leaps in mental health care. As I sit by the door steps of graduate school, the peep inside the great iron gates, reveal to me that there is great progress being made. I cant wait to start practice. Mental health has come a long way from its, brutal origins.
Any takers for VNS?
Neu, P., Heuser, I., & Bajbouj, M. (2005). Cerebral blood flow during vagus nerve stimulation: a transitional doppler study. Neuropsychobiology, 51, 265-268.
Doraiswamy, P. M., MacFall, J., Krishnan, K. R. R., O’Connor, C., Wan, X., Benaur, M., Lewandowski, M., Fortner, M. (1999). Magnetic resonance assessment of cerebral perfusion in depressed cardiac patients. American Journal of Psychiatry, 156, 1641-1644.