Depression vagus nerve stimulation

Vagus nerve stimulation (VNS) may be used for adult patients with treatment-resistant depression. A pulse generator is surgically implanted under the skin of the left chest, and an electrical lead connects the generator to the left vagus nerve. Stimulation of this nerve sends signals to the brain. This therapy is intended to be used along with traditional therapies, such as pharmacotherapy and ECT.20... 

The vagus nerve terminates in the nucleus of the solitary tract with widespread projections, including the locus ceruleus. There are several lines of evidence that support the potential efficacy of vagus nerve stimulation (VNS) for depression, including the following ... 

Conway, C., Sheline, Y., Chibnall, J., George, M., Fletcher, J., Mintun, M. (2006). Cerebral blood flow changes during vagus nerve stimulation for depression. Psychiatry Research, 146, 179—184. 

George, M. S., Rush, A. J., Marangell, L. B., Sackheim, H. A., Brannan, S. K., Davis, S. M., et al. (2005). A one-year comparison of vagus nerve stimulation with treatment as usual for treatment-resistant depression. Biological Psychiatry, 58, 364-373. 

The link between psyche (mind) and soma (body) was confirmed by a commercially available device to control depression. This device consists of an implantable vagus nerve stimulator (Figure 6.22.13), that, when activated, reduced or eliminated depression episodes (Moore, 2005). The same device had been developed to control epileptic seizures, and joins multiple other electrical neural stimulators to control Parkinson s disease, pain, anxiety, chronic headache, bulimia, and others. 

Therapeutic approaches approved by the FDA include spinal cord stimulation for pain, DBS for Parkinson s disease and essential tremor, and vagus nerve stimulation in epilepsy and depression. Techniques stiU at the investigational stj e include DBS for depression, epilepsy, headache, Tourette s syndrome, and pain cortical stimulation in Parkinson s disease, tremor, pain, depression, and stroke rehabilitation and peripheral nerve stimulation for headache and tinnitus. 

Nearly all opioids induce bradycardia (Bowdle, 1998), most likely mediated via central stimulation of the vagus nerve. Cardiovascular depression associated with most opioids is moderate and only the stronger opioids of the fentanyl group induce a more severe effect. Morphine and some of its analogs induce a non-opioid receptor-mediated release of histamine, which can result in a decrease in blood pressure and compensatory... 

Quinidine has anticholinergic properties that can result in the blockade of impulses from the vagus nerve to the heart. This would prevent the slowing of the heart rate that is ordinarily produced by normal vagal stimulation. The resulting increased heart rate counters the direct depressant effect on the pacemaker. This can understandably complicate therapy from the clinical standpoint. The effectiveness of quinidine and procainamide treatment can be traced on ECG by the increase in the Q-T interval, which can be attributed to the increased duration of systole, as well as decreased intraventricular conduction velocity. 

FIGURE 6.22.13 An implanted stimulator presents a train of electrical pulses to the vagus nerve in the chest region. These pulses are then transmitted via the nerve to the brain where they indirectly ameliorate depression. (From Moore, S.K., IEEE Spectr., 42, 16, May 2005. With permission. 2008 IEEE.)... 

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