It is used as an add-on treatment for certain types of intractable epilepsy, cluster headaches, treatment-resistant depression and stroke rehabilitation.
[2][3] In the United States, VNS is approved as adjunctive therapy for those 4 years of age or older with refractory focal onset seizures.
In the European Union, VNS is approved as an adjunctive therapy for patients with either generalized or focal onset seizures without any age restrictions.
[4] It is recommended that VNS is only pursued following an adequate trial of at least 2 appropriately chosen anti-seizure medications and that the patient is ineligible for epilepsy surgery.
[21] A meta-analysis of 74 clinical studies with 3321 patients found that VNS produced an average 51% reduction in seizures after 1 year of therapy.
[24] VNS has also been shown to reduce rates of sudden unexpected death in epilepsy (SUDEP) and to improve quality of life metrics.
[29] A 2022 narrative review concluded that "The use of VNS is an approved, effective and well-tolerated long-term therapy for chronic and treatment-resistant depression.
[30][31] The review also found that, "Many studies and case series demonstrated the efficacy of VNS as an adjuvant procedure for TRD (treatment resistant depression).
[17] Very small studies have shown possible efficacy of VNS for reduction of Sjogren's fatigue,[48][49] and for bowel inflammatory disease.
[50] Piezoelectric BaTiO3 particles conjugated with capsaicin were designed as orally Ingested electrostimulators to activate the vagus nervers to combat obesity.
Multiple lines of evidence suggest that inflammation plays a significant role in epilepsy as well as associated neurobehavioral comorbidities such as depression, autism spectrum disorder and cognitive impairment.
VNS may alter the functional connectivity in several brain regions and enhance synaptic plasticity to reduce excitatory activity involved in seizures.
[66] At the third year the rate of stimulation related adverse effects decreased substantially with shortness of breath being the most common and occurring in 3.2%.
[14][69] The "dose" administered by the device then needs to be set, which is done via a magnetic wand; the parameters adjusted include current, frequency, pulse width, and duty cycle.
[14] The intravenous VNS system produced by LivaNova has stated default settings for use in depression of output power 1.25mA, frequency 20 Hz and pulse width 250 μs, with operation occurring for 30 seconds every 5 minutes (giving a work cycle of 10%).
Then he developed the “electrocompressor” which allowed for the compression of the bilateral carotid arteries as well as electrical stimulation of both the vagus and cervical sympathetic nerves.
The idea was to reduce cardiac output and to stimulate cervical sympathetic nerves to constrict cerebral blood vessels.
[78] In 1997, the US Food and Drug Administration's neurological devices panel met to consider approval of an implanted vagus nerve stimulator (VNS) for epilepsy, requested by Cyberonics (which was subsequently acquired by LivaNova).
[14] In April 2017, the FDA cleared marketing of a handheld noninvasive vagus nerve stimulator, called "gammaCore" and made by ElectroCore LLC, for episodic cluster headaches, under the de novo pathway.
[79][80] In January 2018, the FDA cleared a new use of that device, for the treatment of migraine pain in adults under a 510(k) based on the de novo clearance.
[81][82] In 2020, electroCore's non-invasive VNS was granted an Emergency Use Authorization for treating COVID-19 patients, given Research has shown this pulse train causes airways in the lungs to open its anti-inflammatory effect.
[83] Because the vagus nerve is associated with many different functions and brain regions, clinical research has been done to determine its usefulness in treating many illnesses.