Therapeutic mechanisms and current indications of vagal nerve stimulation

Abstract

Vagal nerve stimulation (VNS) is an established palliative treatment for medically intractable epilepsy. It has also received FDA approval for treatment-resistant depression, headache, and stroke rehabilitation. Studies to determine whether VNS could be the next treatment of choice for other pathologies such as heart failure, Parkinson’s disease, Alzheimer’s disease and inflammatory disease are actively being conducted. The cumulative results of clinical and experimental studies suggest that VNS achieves its anti-epileptic effect by stabilizing activity in the cerebral cortices, inhibiting abnormal excitability via multiple afferent pathways such as the cholinergic, noradrenergic and serotonergic pathways, originating from the nucleus tractus solitarius. Non-invasive transcutaneous stimulation, which has been proved to be safe and effective for clinical conditions such as episodic headaches, is also actively being studied to investigate its therapeutic indications for other pathologies. Non-invasive VNS would increase the opportunity to investigate the physiological effect of VNS with higher precision, through the recruitment of healthy subjects, and could expand the frontiers of basic neuroscience research into neuromodulation.