Vagus nerve stimulation is an interesting new approach to treating neuropsychiatric diseases within the class of brain-stimulation devices sometimes labeled 'neuromodulators'. With vagus nerve stimulation, a battery-powered generator implanted in the chest wall connects to a wire wrapped around the vagus nerve in the neck, and sends intermittent pulses of electricity along the nerve directly into the brain. This mechanism takes advantage of the natural role of the vagus nerve in conveying information into the brain concerning homeostatic information (e.g., hunger, chest pain and respirations). Vagus nerve stimulation therapy is US FDA approved for the adjunctive treatment of epilepsy and has recently been FDA approved for the treatment of medication-resistant depression. Owing to its novel route into the brain, it has no drug-drug interactions or systemic side effects. This treatment also appears to have high long-term tolerability in patients, with low rates of patients relapsing on vagus nerve stimulation or becoming tolerant. However, alongside the excitement and enthusiasm for this new treatment, a lack of Class I evidence of efficacy in treating depression is currently slowing down adoption by psychiatrists. Much more research is needed regarding exactly how to refine and deliver the electrical pulses and how this differentially affects brain function in health and disease.
Bibliographical noteFunding Information:
The authors and their immediate family members have no equity stake in any device or pharmaceutical company. Within the past 5 years, the Brain Stimulation Laboratory has received research grant funding from GlaxoSmithKline, Jazz, Cyberonics, Neuronetics and Neuropace, as well as the Defense Advanced Research Projects Agency (DARPA), the Stanley Foundation, the National Alliance for Research on Schizophrenia and Depression (NARSAD), the Borderline Personality Disorders Foundation (BPDRF), the Charles A Dana Foundation and the National Institutes of Health. The authors hold several TMS-or VNS-related patents. Importantly for this manuscript, MS George and Z Nahas have received speakers fees from Cyberonics and George is a consultant to Cyberonics (Depression Scientific Advisory Board, Mechanisms of Action Advisory Board). George serves or has served within the past 3 years as a paid consultant to, or paid speaker for, several other device companies (Aspect, Cephos, Cyberonics, Neuronetics, Neuropace) and pharmaceutical companies (Abbott, Argolyn, Aventis, Cortex, Darpharma, GlaxoSmithKline, Jazz). His entire yearly compensation for consulting and speaking is less than 10% of his university salary. Both Nahas and JJ Borckardt have current active grants from Cyberonics.
- Brain stimulation
- Vagus nerve