Vagus nerve stimulation (VNS) is a

medical treatment A therapy or medical treatment is the attempted remediation of a health problem, usually following a medical diagnosis. Both words, ''treatment'' and ''therapy'', are often abbreviated tx, Tx, or Tx. As a rule, each therapy has indications an ...

that involves delivering electrical impulses to the

vagus nerve The vagus nerve, also known as the tenth cranial nerve (CN X), plays a crucial role in the autonomic nervous system, which is responsible for regulating involuntary functions within the human body. This nerve carries both sensory and motor fibe ...

. Initially developed by

James Leonard Corning James Leonard Corning (1855 – 1923) was an American neurologist, mainly known for his early experiments on neuraxial blockade in New York City. Education Corning was born in Stamford, Connecticut. When the American Civil War began in 186 ...

to compress or stimulate the carotid sheath, VNS typically refers to an implantable electrode. However, non-invasive VNS delivered transcutaneously via the auricular branch of the vagus nerve, or through the skin to the cervical nerve, is being investigated in clinical research. Invasive VNS is used as an adjunct treatment for certain types of intractable

epilepsy Epilepsy is a group of Non-communicable disease, non-communicable Neurological disorder, neurological disorders characterized by a tendency for recurrent, unprovoked Seizure, seizures. A seizure is a sudden burst of abnormal electrical activit ...

, cluster headaches, migraine,

treatment-resistant depression Treatment-resistant depression (TRD) is often defined as major depressive disorder in which an affected person does not respond adequately to at least two different antidepressant medications at an adequate dose and for an adequate duration. Inad ...

and stroke rehabilitation.

Medical use

Epilepsy

VNS is used to treat drug-resistant epilepsy. For refractive epilepsy, cervical VNS on the left side is

FDA The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ...

-approved. 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. It is recommended that VNS is only pursued following an adequate trial of at least 2 appropriately chosen

anti-seizure medications Anticonvulsants (also known as antiepileptic drugs, antiseizure drugs, or anti-seizure medications (ASM)) are a diverse group of pharmacological agents used in the treatment of epileptic seizures. Anticonvulsants are also used in the treatment ...

and that the patient is ineligible for epilepsy surgery. This is because epilepsy surgery is associated with a higher probability of resulting in seizure freedom. Patients who have poor adherence or tolerance of anti-seizure medications may be good candidates for VNS. VNS may provide benefit for particular epilepsy syndromes and seizure types such as Lennox-Gastaut syndrome,

tuberous sclerosis complex Tuberous sclerosis complex (TSC) is a rare multisystem autosomal dominant genetic disease that causes non-cancerous tumours to grow in the brain and on other vital organs such as the kidneys, heart, liver, eyes, lungs and skin. A combinatio ...

related epilepsy, refractory absence seizures, and

atonic seizure An atonic seizure (also called drop seizure, akinetic seizure, astatic seizure, or drop attack) is a type of seizure that consists of partial or complete loss of muscle tone that is caused by temporary alterations in brain function. These seizures ...

s. There are also reports of VNS being successfully utilized in patients with refractory and super-refractory

status epilepticus Status epilepticus (SE), or status seizure, is a medical condition with abnormally prolonged seizures. It can have long-term consequences, manifesting as a single seizure lasting more than a defined time (time point 1), or 2 or more seizures over ...

Cluster headaches & Migraine

The UK National Institute for Health and Care Excellence (NICE) in the UK recommends VNS for cluster headaches. In 2017 the FDA approved the non-invasive gammaCore VNS system for treatment of episodic cluster headache and expanded its approved usage to acute treatment of pain associated with migraine. Two randomized, double-blind, and sham-controlled studies have administered nVNS to patients with episodic cluster headaches; both demonstrated a significant effect in reducing acute cluster attacks.

Treatment-resistant depression

VNS is used to treat treatment-resistant

major depressive disorder Major depressive disorder (MDD), also known as clinical depression, is a mental disorder characterized by at least two weeks of pervasive depression (mood), low mood, low self-esteem, and anhedonia, loss of interest or pleasure in normally ...

(TR-MDD). For treatment resistant depression, cervical VNS on the left side is FDA-approved. The UK

NICE Nice ( ; ) is a city in and the prefecture of the Alpes-Maritimes department in France. The Nice agglomeration extends far beyond the administrative city limits, with a population of nearly one million

Chronic pain

VNS has been used to treat

chronic pain Chronic pain is pain that persists or recurs for longer than 3 months.https://icd.who.int/browse/2025-01/mms/en#1581976053 It is also known as gradual burning pain, electrical pain, throbbing pain, and nauseating pain. This type of pain is in cont ...

due to various causes, although the mechanisms for this relief have yet to be determined.

Heart failure

VNS has shown to be of value in the treatment of

heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome caused by an impairment in the heart's ability to Cardiac cycle, fill with and pump blood. Although symptoms vary based on which side of the heart is affected, HF ...

. One study did not show a reduction in death rates, but did show improvement in six-minute hall walk duration and quality of life.

Atrial fibrillation

Animal studies have shown the capacity of low-level VNS to reduce inducibility of

atrial fibrillation Atrial fibrillation (AF, AFib or A-fib) is an Heart arrhythmia, abnormal heart rhythm (arrhythmia) characterized by fibrillation, rapid and irregular beating of the Atrium (heart), atrial chambers of the heart. It often begins as short periods ...

. This effect has been proposed to be due to inhibition of the

ganglionated plexi Ganglionated plexi (GP, also called Ganlionic plexi) comprise the intrinsic cardiac autonomic nervous system composed of autonomic ganglia of the heart atrium and ventricles. Cholinergic neurons throughout the GPs project to all areas of the hea ...

Stroke treatment and rehabilitation

VNS can be used either invasively or non-invasively to treat ischemic stroke. Invasive VNS can only be applied invasively (by surgery), but non-invasive VNS can be used in acute settings. In 2021, the U.S.

Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respo ...

approved the MicroTransponder Vivistim Paired VNS System (Vivistim System) to treat moderate to severe upper extremity motor deficits associated with chronic ischemic stroke.

Efficacy

Epilepsy

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. Approximately 50% of patients had an equal to or greater than 50% reduction in seizures at the time of last follow-up. Long-term studies have shown that response to VNS increases over time. For instance, a study that followed 74 patients for 10–17 years found a seizure frequency reduction of 50-90% in 38.4%, 51.4%, 63.6% and 77.8% of patients at 1-, 2-, 10- and 17-years following implantation, respectively. Approximately, 8% have total resolution of seizures. VNS has also been shown to reduce rates of sudden unexpected death in epilepsy (SUDEP) and to improve quality of life metrics. A number of predictors of a favorable clinical response have been identified including epilepsy onset > 12 years of age, generalized epilepsy type, non-lesional epilepsy, posttraumatic epilepsy and those who have less than a 10-year history of seizures. Long-term cognitive outcomes are at least stable following VNS. One study of children with epilepsy found that a post hoc analysis revealed a dose–response correlation for VNS.

Depression

A 2022 narrative review concluded that VNS is an effective and well-tolerated therapy for chronic and treatment-resistant depression. Importantly, the review also noted that the therapeutic effect of VNS in this context may take 3–12 months to materialize but may be persistent long-term. One study of only 10 weeks found no effect. A 2020 review concluded "Reviewed studies strongly suggest that VNS ameliorates depressive symptoms in drug-resistant epileptic patients and that the VNS effect on depression is uncorrelated to seizure response. In one study higher electrical dose parameters were associated with response durability.

Well-being

VNS may have positive well-being, mood and quality of life effects. Studies have found improvements in standard patient-reported mood assessment scales in adult patients with epilepsy after using VNS, and some have found no association between mood change and reduction in seizure frequency. Another study of epilepsy patients measured a general mood improvement, and suggested that VNS may improve unspecific states of indisposition and dysphoria. Patients with comorbid depression have been found to have mood improvements with VNS therapy. Quality of life (QOL) improvement was also associated with VNS use. One study of children with epilepsy found that better quality of life outcomes after VNS implantation were strongly associated with shorter duration of preoperative seizures and implantation at a young age.

Heart diseases

cardiac arrest Cardiac arrest (also known as sudden cardiac arrest CA is when the heart suddenly and unexpectedly stops beating. When the heart stops beating, blood cannot properly Circulatory system, circulate around the body and the blood flow to the ...

VNS used in conjunction with

cardiopulmonary resuscitation Cardiopulmonary resuscitation (CPR) is an emergency procedure used during Cardiac arrest, cardiac or Respiratory arrest, respiratory arrest that involves chest compressions, often combined with artificial ventilation, to preserve brain function ...

(CPR) has been shown to increase recovery time (

return of spontaneous circulation Return of spontaneous circulation (ROSC) is the resumption of a sustained heart rhythm that perfuses the body after cardiac arrest. It is commonly associated with significant respiratory effort. Signs of return of spontaneous circulation include b ...

) as well as reduce the number of shocks required when used in conjunction with

cardioversion Cardioversion is a medical procedure by which an abnormally fast heart rate (tachycardia) or other cardiac arrhythmia is converted to a normal rhythm using electricity or drugs. Synchronized electrical cardioversion uses a therapeutic dose of ...

. Numerous pre-clinical studies have shown the effectiveness of VNS in reducing

and

hypertension Hypertension, also known as high blood pressure, is a Chronic condition, long-term Disease, medical condition in which the blood pressure in the artery, arteries is persistently elevated. High blood pressure usually does not cause symptoms i ...

COVID-19

In 2020 during the

COVID-19 pandemic The COVID-19 pandemic (also known as the coronavirus pandemic and COVID pandemic), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), began with an disease outbreak, outbreak of COVID-19 in Wuhan, China, in December ...

, the gammaCore Sapphire CV non-invasive VNS system was granted emergency use authorization for suspected COVID-19 patients experiencing "asthma-related dyspnea and reduced airflow, and for whom approved drug therapies are not tolerated or provide insufficient symptom relief." Clinical trials show VNS reduces inflammation in COVID patients. In patients with

long COVID Long may refer to: Measurement * Long, characteristic of something of great duration * Long, characteristic of something of great length * Longitude (abbreviation: long.), a geographic coordinate * Longa (music), note value in early music mens ...

, VNS is efficacious in reducing inflammatory markers and chronic fatigue.

Other possible efficacy areas

Very small studies have shown possible efficacy of VNS for reduction of Sjogren's

fatigue Fatigue is a state of tiredness (which is not sleepiness), exhaustion or loss of energy. It is a signs and symptoms, symptom of any of various diseases; it is not a disease in itself. Fatigue (in the medical sense) is sometimes associated wit ...

, and for bowel inflammatory disease. Piezoelectric

BaTiO3 Barium titanate (BTO) is an inorganic compound with chemical formula BaTiO3. It is the barium salt of metatitanic acid. Barium titanate appears white as a powder and is transparent when prepared as large crystals. It is a ferroelectric, pyroelect ...

particles conjugated with

capsaicin Capsaicin (8-methyl-''N''-vanillyl-6-nonenamide) (, rarely ) is an active component of chili peppers, which are plants belonging to the genus ''Capsicum''. It is a potent Irritation, irritant for Mammal, mammals, including humans, and produces ...

were designed as orally ingested electrostimulators to activate the vagus nerves to combat

obesity Obesity is a medical condition, considered by multiple organizations to be a disease, in which excess Adipose tissue, body fat has accumulated to such an extent that it can potentially have negative effects on health. People are classifi ...

. This intervention has not yet been tested on the human body.

Mechanisms of action

The causes of VNS efficacy are not well understood. Mechanisms which may account for the efficacy of VNS include:

Cortical desynchronization

There is evidence that VNS results in cortical desynchronization in epilepsy patients who had a favorable clinical response relative to those who did not. This makes sense given that seizures consist of abnormal hypersynchronous activity in the brain.

Reducing inflammation

Multiple lines of evidence suggest that

inflammation Inflammation (from ) is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. The five cardinal signs are heat, pain, redness, swelling, and loss of function (Latin ''calor'', '' ...

plays a significant role in epilepsy as well as associated neurobehavioral comorbidities such as depression, autism spectrum disorder and cognitive impairment. There is evidence that VNS has an

anti-inflammatory Anti-inflammatory is the property of a substance or treatment that reduces inflammation, fever or swelling. Anti-inflammatory drugs, also called anti-inflammatories, make up about half of analgesics. These drugs reduce pain by inhibiting mechan ...

effect through both peripheral and central mechanisms.

Changing neurotransmitter activity

VNS can change the activity of several

neurotransmitter A neurotransmitter is a signaling molecule secreted by a neuron to affect another cell across a Chemical synapse, synapse. The cell receiving the signal, or target cell, may be another neuron, but could also be a gland or muscle cell. Neurotra ...

systems involving

serotonin Serotonin (), also known as 5-hydroxytryptamine (5-HT), is a monoamine neurotransmitter with a wide range of functions in both the central nervous system (CNS) and also peripheral tissues. It is involved in mood, cognition, reward, learning, ...

norepinephrine Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic compound, organic chemical in the catecholamine family that functions in the brain and human body, body as a hormone, neurotransmitter and neuromodulator. The ...

acetylcholine Acetylcholine (ACh) is an organic compound that functions in the brain and body of many types of animals (including humans) as a neurotransmitter. Its name is derived from its chemical structure: it is an ester of acetic acid and choline. Par ...

, dopamine, and

GABA GABA (gamma-aminobutyric acid, γ-aminobutyric acid) is the chief inhibitory neurotransmitter in the developmentally mature mammalian central nervous system. Its principal role is reducing neuronal excitability throughout the nervous system. GA ...

. The vagus nerve has projects reaching directly in the

nucleus of the solitary tract The solitary nucleus (SN) (nucleus of the solitary tract, nucleus solitarius, or nucleus tractus solitarii) is a series of neurons whose cell bodies form a roughly vertical column of grey matter in the medulla oblongata of the brainstem. Their ax ...

and affects a range of subcortical structures including the

locus coeruleus The locus coeruleus () (LC), also spelled locus caeruleus or locus ceruleus, is a nucleus in the pons of the brainstem involved with physiological responses to stress and panic. It is a part of the reticular activating system in the reticular ...

, which serves as the primary source of cortical noradrenaline in the brain. Stimulation of the vagus nerve in rats has been shown to consistently elevate cortical noradrenaline levels in both the short and long-term. Chronic stimulation of the vagus nerve has also been noted to increase serotonin release and firing in the dorsal raphe nuclei. Other studies in rats have also demonstrated a VNS-dependent increase in dopamine concentrations within the

prefrontal cortex In mammalian brain anatomy, the prefrontal cortex (PFC) covers the front part of the frontal lobe of the cerebral cortex. It is the association cortex in the frontal lobe. The PFC contains the Brodmann areas BA8, BA9, BA10, BA11, BA12, ...

and

nucleus accumbens The nucleus accumbens (NAc or NAcc; also known as the accumbens nucleus, or formerly as the ''nucleus accumbens septi'', Latin for ' nucleus adjacent to the septum') is a region in the basal forebrain rostral to the preoptic area of the hypo ...

Impacting the gut-brain axis

VNS influences the vagus nerve, which plays a role in the gut-brain axis. Research has shown that VNS has an anti-inflammatory effect in patents with irritable bowel syndrome. VNS has been shown to reduce cytokine production as well as modulate gut permeability in patients prior to severe burn injuries. Additionally, VNS has been shown to restore dysbiosis in IBD.

Indirect stimulation of brain structures

Some believe that indirect stimulation of the thalamus may be a key mechanism in VNS efficacy.

Adverse events

Adverse events related to the surgical procedure

A large 25-year retrospective study of 247 patients found a surgical complication rate of 8.6%. The common adverse events included infection in 2.6%,

hematoma A hematoma, also spelled haematoma, or blood suffusion is a localized bleeding outside of blood vessels, due to either disease or trauma including injury or surgery and may involve blood continuing to seep from broken capillaries. A hematoma is ...

at the surgical site in 1.9% and vocal cord palsy in 1.4%. In some rare cases where the VNS is not effective, surgery may be necessary to remove the VNS system. The surgery may remove both the generator and the lead.

Side effects of VNS

The most common stimulation related side effect at 1 year following implantation are

hoarseness A hoarse voice, also known as dysphonia or hoarseness, is when the voice involuntarily sounds breathy, raspy, or strained, or is softer in volume or lower in pitch. A hoarse voice can be associated with a feeling of unease or scratchiness in the ...

in 28% and paraesthesias in the throat-chin region in 12%. 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%. In general, VNS is well tolerated and side effects diminish over time. Also, side effects can be controlled by changing the stimulation parameters. One small study found

sleep apnea Sleep apnea (sleep apnoea or sleep apnœa in British English) is a sleep-related breathing disorder in which repetitive Apnea, pauses in breathing, periods of shallow breathing, or collapse of the upper airway during sleep results in poor vent ...

in as many as 28% of adults with epilepsy treated with VNS. Another small study found significant daytime drowsiness, which could be relieved by reducing the stimulation intensity. Because vagal tone can reduce

heart rate Heart rate is the frequency of the cardiac cycle, heartbeat measured by the number of contractions of the heart per minute (''beats per minute'', or bpm). The heart rate varies according to the body's Human body, physical needs, including the nee ...

, VNS carries the risk of

bradycardia Bradycardia, also called bradyarrhythmia, is a resting heart rate under 60 beats per minute (BPM). While bradycardia can result from various pathological processes, it is commonly a physiological response to cardiovascular conditioning or due ...

(excessively slow heart rate, and even of stopping the heart. A range of side effects are possible but rare.

Devices and procedures

Intravenous devices

The device consists of a generator the size of a matchbox that is implanted under the skin below the person's

collarbone The clavicle, collarbone, or keybone is a slender, S-shaped long bone approximately long that serves as a strut between the shoulder blade and the sternum (breastbone). There are two clavicles, one on each side of the body. The clavicle is the ...

. Lead wires from the generator are tunnelled up to the patient's neck and wrapped around the left vagus nerve at the

carotid sheath The carotid sheath is a condensation of the deep cervical fascia enveloping multiple vital neurovascular structures of the neck, including the common and internal carotid arteries, the internal jugular vein, the vagus nerve (CN X), and ansa c ...

, where it delivers electrical impulses to the nerve. Implantation of the VNS device is usually done as an out-patient procedure. The procedure goes as follows: an incision is made in the upper left chest and the generator is implanted into a little "pouch" on the left chest under the collarbone. A second incision is made in the neck, so that the surgeon can access the vagus nerve. The surgeon then wraps the leads around the left branch of the vagus nerve, and connects the electrodes to the generator. Once successfully implanted, the generator sends electric impulses to the vagus nerve at regular intervals. The left vagus nerve is stimulated rather than the right because the right plays a role in cardiac function such that stimulating it could have negative cardiac effects. 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.

Example of stimulation metrics

The intravenous VNS system produced by

LivaNova LivaNova, plc is an Italian-American medical device manufacturer based in the UK. The company develops devices used for cardiac surgery and neuromodulation. The company was formed in 2015 by a $2.7B merger between Houston, Texas-based Cyberonic ...

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%). The non-invasive gammaCore device delivers 5000 Hz pulses at a frequency of 25 Hz at an intensity of up to 60mA or 30V. Stimulations may be administered for up to two minutes in one sitting, and a maximum of 30 stimulations can be delivered over a 24h period.

External devices

External devices work by transcutaneous stimulation and do not require surgery. Electrical impulses are targeted at the cervical branch of the vagus nerve in the neck, or aurical (ear), at points where branches of the vagus nerve have cutaneous representation. Auricular VNS should be located at the

concha A Concha (Spanish, 'shell'), plural conchas, is a traditional Mexican sweet bread (''pan dulce'') with similar consistency to a brioche. Conchas get their name from their round shape and their striped, seashell-like appearance. A concha consis ...

or inner tragus. The GammaCore transcutaneous cervical VNS system is recommended by The National Institute for Health and Care Excellence (NICE) for cluster headaches.

History

1880s - proposed use to reduce cerebral blood flow

James L. Corning (1855-1923) was an American neurologist who developed the first device for stimulating the vagus nerve towards the end of the 19th century. At this time a widely held theory was that excessive blood flow caused seizures. In the 1880s Corning designed a pronged instrument called the “carotid fork” to compress the

carotid artery Carotid artery may refer to: * Common carotid artery, often "carotids" or "carotid", an artery on each side of the neck which divides into the external carotid artery and internal carotid artery * External carotid artery, an artery on each side of ...

for the acute treatment of seizures. In addition, he developed the “carotid truss” for prolonged compression of the carotid arteries as a long-term preventative treatment for epilepsy. 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. Corning reported dramatic benefits however it was not accepted by his colleagues and ultimately was forgotten.

1930s - research on effects on central nervous system

In the 1930s Biley and Bremer demonstrated the direct influence of VNS on the

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain, spinal cord and retina. The CNS is so named because the brain integrates the received information and coordinates and influences the activity o ...

. In the 1940s and 1950s vagal nerve stimulation was shown to affect EEG activity.

1980s - use for epilepsy

In 1985 neuroscientist Jacob Zabara proposed that VNS could be used to treat epilepsy. He then demonstrated its efficacy in animal experiments. The first human was implanted with a VNS for the treatment of epilepsy in 1988.

1997 onwards - approved medical uses

In 1997, the US

'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

). The FDA approved an implanted VNS for TR-MDD in 2005. 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 Cluster headache is a neurological disorder characterized by recurrent severe headaches on one side of the head, typically around the eye(s). There is often accompanying eye watering, nasal congestion, or swelling around the eye on the affecte ...

, under the de novo pathway. In January 2018, the FDA cleared a new use of that device, for the treatment of migraine pain in adults under a

510(k) The United States Federal Food, Drug, and Cosmetic Act (abbreviated as FFDCA, FDCA, or FD&C) is a set of laws passed by the United States Congress in 1938 giving authority to the U.S. Food and Drug Administration (FDA) to oversee the safety of ...

based on the de novo clearance. In 2020, electroCore's non-invasive VNS was granted an Emergency Use Authorization for treating

COVID-19 Coronavirus disease 2019 (COVID-19) is a contagious disease caused by the coronavirus SARS-CoV-2. In January 2020, the disease spread worldwide, resulting in the COVID-19 pandemic. The symptoms of COVID‑19 can vary but often include fever ...

patients, given research indicating VNS causes an opening of end terminals in the airways and an anti-inflammatory effect. In 2021, the same gammaCore nVNS device received Section 510(k) clearance from the FDA to expand its usage for patients with two forms of trigeminal autonomic cephalagia--

hemicrania continua Hemicrania continua (HC) is a persistent unilateral headache that responds to indomethacin. It is usually unremitting, but rare cases of remission have been documented. Hemicrania continua is considered a primary headache disorder, meaning that ...

and

paroxysmal hemicrania Chronic paroxysmal hemicrania (CPH) is a severe debilitating unilateral headache usually affecting the area around the eye. It normally consists of multiple severe, yet short, headache attacks affecting only one side of the cranium. Retrospective ...

Research areas

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. These include various

anxiety disorder Anxiety disorders are a group of mental disorders characterized by significant and uncontrollable feelings of anxiety and fear such that a person's social, occupational, and personal functions are significantly impaired. Anxiety may cause phys ...

, alcohol addiction, chronic

, prevention of arrhythmias that can cause

sudden cardiac death Cardiac arrest (also known as sudden cardiac arrest ''SCA is when the heart suddenly and unexpectedly stops beating. When the heart stops beating, blood cannot properly circulate around the body and the blood flow to the brain and other org ...

autoimmune disorders An autoimmune disease is a condition that results from an anomalous response of the adaptive immune system, wherein it mistakenly targets and attacks healthy, functioning parts of the body as if they were foreign organisms. It is estimated tha ...

irritable bowel syndrome Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by a group of symptoms that commonly include abdominal pain, abdominal bloating, and changes in the consistency of bowel movements. These symptoms may ...

Alzheimer's disease Alzheimer's disease (AD) is a neurodegenerative disease and the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in remembering recent events. As the disease advances, symptoms can include problems wit ...

Parkinson's disease Parkinson's disease (PD), or simply Parkinson's, is a neurodegenerative disease primarily of the central nervous system, affecting both motor system, motor and non-motor systems. Symptoms typically develop gradually and non-motor issues become ...

, several

conditions, inflammatory disorders,

fibromyalgia Fibromyalgia (FM) is a functional somatic syndrome with symptoms of widespread chronic pain, accompanied by fatigue, sleep disturbance including awakening unrefreshed, and Cognitive deficit, cognitive symptoms. Other symptoms can include he ...

and

migraines Migraine (, ) is a complex neurological disorder characterized by episodes of moderate-to-severe headache, most often unilateral and generally associated with nausea, and light and sound sensitivity. Other characterizing symptoms may includ ...

. A 2022 study showed that chronic VNS showed strong antidepressant and anxiolytic effects, and improved memory performance in an Alzheimer's Disease animal model.

Medical use

Epilepsy

Cluster headaches & Migraine

Treatment-resistant depression

Heart failure

Atrial fibrillation

Stroke treatment and rehabilitation

Efficacy

Epilepsy

Depression

Well-being

Heart diseases

COVID-19

Other possible efficacy areas

Mechanisms of action

Cortical desynchronization

Reducing inflammation

Changing neurotransmitter activity

Impacting the gut-brain axis

Indirect stimulation of brain structures

Adverse events

Adverse events related to the surgical procedure

Side effects of VNS

Devices and procedures

Intravenous devices

Example of stimulation metrics

External devices

History

1880s - proposed use to reduce cerebral blood flow

1930s - research on effects on central nervous system

1980s - use for epilepsy

1997 onwards - approved medical uses

Research areas

See also

References

Further reading