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Nerve stimulation study offers hope for depression According to clinical trial research released by Mark George, M.D., and co-investigators, vagus nerve stimulation (VNS ) a mild electrical stimulation of the vagus nerve in the neck, shows promising results in treating patients suffering from severe treatment-resistant depression.  In the 30-patient, three-month pilot study of VNS conducted at the University of Texas Southwestern Medical Center, MUSC, the Columbia (NY) College of Physicians and Surgeons and Baylor College of Medicine, 40 percent of the patients treated showed a 50 percent or greater improvement in their depression according to the Hamilton Rating Scale for Depression (HRSD).  Half of the patients demonstrated a greater than 50 percent improvement as measured by the Montgomery Asberg Depression Rating Scale (MADRS). The results of the study will be published in the journal Biological Psychiatry in February 2000 and are available today online at <http://www.elsevier.com/locate/biopsych> The VNS study results showed that the majority of the patients who responded to VNS maintained that response for months after the initial treatment period, with no patients sustaining a relapse so far. Seventeen percent of the patients exited the 3-month study as “complete responders” with a 28-item HRSD less than or equal to 10, meaning that they did not have significant depressive symptoms.  Ten responders had reached at least one scheduled long-term follow-up visit, with five responders being treated for at least six months and one responder being treated for one year.   Of the responders with long-term VNS treatment experience, seven of the 10 or 70 percent had achieved complete response, suggesting that the beneficial effects of VNS were maintained or improved over time. Similar results of improved efficacy over time have been reported in studies of VNS in patients with refractory epilepsy.   In the United States alone, approximately 18 million people suffer from depression, one million of which have severe treatment-resistant depression. There are limited treatment options for people with severe, treatment-resistant depression, with electroconvulsive therapy (ECT) being one of the primary treatment options.  ECT typically consists of seven to 12 separate treatment sessions per year over multiple years.  During each session, an electrical shock is administered under general anesthesia to induce a generalized seizure. Many patients require ongoing or maintenance ECT for months or years after the initial treatment series. Relapse rates of depression after the initial series of ECT sessions can be as high as 50 percent to 70 percent in patents with severe, treatment-resistant depression. During the course of the pilot study, 30 adult patients with non-psychotic, chronic treatment-resistant depression were treated with VNS. Each patient either was in the midst of a Major Depressive Episode (MDE) that had lasted longer than two years or they had at least four MDEs in their lifetime.  All patients had also not responded to at least two robust medication trials in the treatment of their current MDE, and more than half had not responded to at least four medication trials. Fifty-seven percent of the patients had also been non-responsive to ECT or had been unable to tolerate it. The 30 patients had a pacemaker-like generator implanted under the skin in the upper chest and a stimulation electrode tunneled from the chest to the neck where it was attached to the vagus nerve. Following a two week recovery period, stimulation parameters were adjusted and for the next eight weeks, intermittent VNS was provided at a fixed (maximum comfortably tolerated) dose. The device used in the study, the implant location and technique, the intermittent stimulation parameters and the side-effects reported during the pilot study were similar to those for VNS in patients with epilepsy, with the most common side-effects being voice alteration and surgically-related pain. “I believe that we may be one exciting step closer to unlocking the neurological riddle of depression,” said George, professor of psychiatry, radiology and neurology and director of the Brain Stimulation laboratory. “For some time there has been strong evidence that VNS has improved overall mood among epilepsy patients, and this new research confirms that VNS offers significant potential in treating the severely depressed.”  About Vagus Nerve Stimulation Vagus Nerve Stimulation therapy is delivered by the Cyberonics NCP System, an implantable medical device similar to a cardiac pacemaker.  A stopwatch-sized generator is implanted in the left chest and a nerve stimulation electrode is attached to the vagus nerve in the neck in a one to two hour procedure typically done on an outpatient basis.  Using an external programmer, the physician can set or reset the stimulation parameters of the device. The system delivers preprogrammed intermittent  for example, 30 seconds on, five minutes off electrical pulses to the vagus nerve 24 hours a day.  The first human implant of the system occurred in 1988. On July 16, 1997, the FDA approved VNS with the Cyberonics NCP System as an adjunctive therapy for the treatment of medically refractory partial onset seizures in adults and adolescents over 12 years of age.  To date, more than 6,500 epilepsy patients in 24 countries have accumulated over 6,000 patient years of experience using Vagus Nerve Stimulation.