iarjimphIARJIMPHIARJIMPH2709-331Xhttps://doi.org/10.47310/iarjimph.2021.v02i01.017Vagus Nerve Stimulation Therapy (VNS) in Refractory Epilepsy: What we know so farAnshChaudharyBhupendraChaudharyVagus Nerve Stimulation (VNS) is an established and promising neurophysiological treatment modality for patients with refractory epilepsy who are either unsuitable candidates for surgical intervention or continue to experience seizures despite epilepsy surgery. Since its approval by the United States Food and Drug Administration in 1997, VNS has become the second most commonly performed intervention for refractory epilepsy in the United Kingdom after temporal lobectomy. The technique involves surgical implantation of a programmable device in the left side of the chest, similar to a cardiac pacemaker, with electrodes connected to the left vagus nerve. The preference for left-sided implantation is attributed to the relatively limited cardiac efferent innervation of the left vagus nerve, thereby minimizing potential cardiac complications. The device delivers intermittent, low-frequency electrical stimulation to the vagus nerve, resulting in activation of vagal nuclei particularly the nucleus of the solitary tract and subsequent widespread cortical and subcortical modulation. This neuromodulation increases seizure threshold and accounts for its antiepileptic effects, although the precise mechanisms remain incompletely understood. VNS is indicated as adjunctive therapy in patients aged 12 years and above with partial seizures, with or without secondary generalization, as well as in certain generalized epilepsy syndromes, including Lennox–Gastaut syndrome. VNS is generally well tolerated, with most adverse effects being transient and related to laryngeal innervation, such as hoarseness and throat paresthesia. Serious cardiac complications are rare. In addition to seizure reduction, VNS offers several advantages, including continuous long-term efficacy, lack of drug interactions and beneficial neuropsychological effects on mood, alertness and quality of life. Its expanding therapeutic potential also includes applications in depression, chronic pain and neurodegenerative disorders.