Vagal nerve stimulation

The development of vagal nerve stimulation (VNS), particularly noninvasive VNS (nVNS) for management of primary headaches is a relatively novel indication in the field of neuromodulation, with FDA approval being granted in 2017. Noninvasive VNS has been shown to be an effective therapeutic modality for various primary headache conditions. Types of headaches that have been identified as responders to treatment with VNS include chronic migraine, high frequency episodic migraine, chronic cluster headache, and episodic cluster headache. Noninvasive VNS is performed using a small, handheld device that applies electronic stimulation to areas where the vagus nerve descends. The device can induce antinociception through transcutaneous vagus nerve stimulation at the external ear (auricular branch of vagus nerve) or neck (the cervical branch of vagus nerve). There are several transcutaneous vagus nerve stimulator devices including NEMOS and gammaCore. Related to nVNS's favorable side effect profile and efficacy, nVNS shows promise for primary headache patients unable to tolerate side effects of pharmacotherapy and whose headaches are refractory to conventional treatments. Patient satisfaction in nVNS for chronic migraine is relatively high at 88.5%, with 46.7% of study participants achieving >50% treatment response as defined by reduction in average number of migraine days in a month per study protocol.