Vagus nerve stimulation (VNS) is approved in Europe for the treatment of drug-resistant epilepsy (DRE) and refractory depression. The treatment is performed by stimulating the vagus nerve. The vagus nerve is the tenth of twelve cranial nerves and innervates several organs such as the heart, lung and gastrointestinal tract. VNS was first approved in the European Union in 1994 followed by approval in the US three years later. In 2010, a transcutaneous vagus nerve stimulation (t-VNS) system was approved in Europe.