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Vagus nerve stimulation (VNS) therapy for epilepsy

What is VNS therapy for epilepsy?

VNS therapy involves a small electrical device, like a pacemaker, which is implanted under the skin of your chest. The device sends electrical impulses to your brain through a nerve in your neck called the vagus nerve. The aim is to reduce the number of seizures you have and make them less severe.

How does VNS therapy work?

VNS Therapy

VNS therapy uses the VNS system, which is made up of 3 parts:

  • A small pacemaker-like device, called a generator
  • A thin, flexible wire, called a lead
  • A hand-held magnet

The vagus nerve sends messages between the brain and other parts of the body. In VNS therapy, a generator is connected to the vagus nerve by a lead. The generator is programmed to send electrical impulses to the vagus nerve at regular intervals, all day, every day. These impulses are then carried by the vagus nerve to the brain. This regular stimulation can help to reduce the number of seizures you have and make them less severe.

You can also sweep the hand-held magnet over the generator to send more impulses to the vagus nerve. This could be if you have an aura (warning) before a seizure, if you feel a seizure starting, or when you are having a seizure. Some people find that using the magnet stops a seizure happening, shortens the seizure or makes the seizure less severe. A carer, or family member, can also use the magnet, if they see you having a seizure. The magnet can also be used to stop the stimulation for a short time.

Newer models of the VNS generator can also detect increases in heart-rate. In some people with epilepsy an increase in heart-rate can be a sign that they are having a seizure. When the generator detects an increase in heart-rate, it automatically sends more impulses to the vagus nerve. This may help to stop a seizure happening or make it less severe.

Can I have VNS therapy?

There are strict criteria for having VNS therapy on the NHS, and only some people with epilepsy are eligible. It is restricted for adults and children with epilepsy when other treatments have not worked or are not suitable. To be eligible for VNS therapy you must still be having seizures despite trying a number of different epilepsy medicines, or your epilepsy medicine causes you too many side-effects. You must also be unsuitable for epilepsy brain surgery, or you have had brain surgery but are still having seizures.

If you think VNS therapy might help you, talk to your epilepsy specialist.

What does VNS surgery involve?

Surgery to implant the VNS system is carried out by a neurosurgeon, usually under general anaesthetic. The operation takes between 1 and 2 hours and you usually go home the same day, or the next day. The neurosurgeon makes 2 small cuts, 1 in a natural crease on the left of your neck, and 1 in the left-hand side of your chest, below your collarbone. The generator is placed under the skin in your chest. A lead is inserted under the skin to connect the generator to the left vagus nerve in the neck.

As with any operation, there is a slight risk of reaction to the anaesthetic. There is also a small risk of bleeding and infection. Your surgeon will give you more information before the operation takes place.

You might have some pain for a while from the area of the implant after VNS surgery. Your doctor can prescribe something for this.

What happens after VNS surgery?

The generator is usually left switched off for two weeks after surgery. This is to help your body heal. After that, it is usually switched on by a specialist nurse in a clinic. They will gradually increase the settings over a number of weeks. This gives you a chance to get used to the stimulation over time.

What are the benefits of VNS?

The benefits of VNS can include the following:

  • Having fewer seizures
  • Having less severe seizures or shorter seizures
  • Having improved quality of life

You might not see any improvement in your seizures at first. You might find your seizure control slowly improves over the first 2 years after the VNS system is fitted. For most people, VNS does not stop seizures completely.

Will I get side-effects from VNS?

The most common side-effect reported from VNS is hoarseness/a change in voice. Other common side effects include:

  • Sore throat
  • Shortness of breath
  • Coughing

Other possible side-effects include palpitations, difficulty swallowing and stomach discomfort. The side-effects of VNS usually happen during stimulation periods, and may improve over time. If you find the side-effects uncomfortable talk to your epilepsy nurse. They may be able to help by altering the level of stimulation.

You can find a list of possible side-effects in the VNS Patient Manual.

Will I still need to take epilepsy medicine after the VNS system has been fitted?

VNS is designed to be used in addition to epilepsy medicine, not to replace it. Most people need to keep taking epilepsy medicine after they have had a VNS system fitted. Some people are able to reduce the amount of epilepsy medicine they take over time. You will be able to talk to your epilepsy specialist about any possible changes to your medicine.

Is it safe to have an MRI scan with a VNS system fitted?

Some types of magnetic resonance imaging (MRI) are dangerous when you have a VNS system fitted and could cause you serious injury. They can also be dangerous if you have had the VNS system removed, but still have some of the lead remaining. If an MRI is recommended for you it’s important that everyone involved in the scan knows about your VNS system. They may need to take precautions to carry out the scan safely.

Can I go through airport security scanners with a VNS system fitted?

Airport security scanners should not affect the device or be affected by it. The makers of the VNS therapy system recommend that to be safe, you should walk through the scanner at a steady pace, not linger in the area and stay at least 40 centimetres from the equipment.

You can find a full list of VNS system precautions in the VNS Patient Manual.   

How long does the generator last?

At some point, the generator will need replacing when the battery runs low. The generator battery can last between 1 and 16 years, depending on the model and settings used. Your doctor or nurse can tell when the battery is running down during your follow up appointments. They will then arrange for a new generator to be fitted. This involves a small operation, which lasts less than an hour.

How do I get a replacement magnet?

If you need a replacement magnet, contact your epilepsy specialist nurse. They should be able to provide you with a new magnet free of charge.    

How can I find out more?

You can get more information about VNS therapy from the website of Livanova, who make the VNS therapy system.

If you’re thinking about VNS therapy for your child, this site by Livanova may help them understand more.

What other systems are available for treating epilepsy?

A number of companies have launched or are developing other systems to treat epilepsy. At the moment, none has been approved for treatment on the NHS. Examples include:

Transcutaneous vagus nerve stimulation (t-VNS) – the Nemos device

This device stimulates the vagus nerve through the ear. It is made up of an external stimulator, which is connected by a wire to an earpiece worn in the ear. More information is available from the Nemos website.

External trigeminal nerve stimulation (eTNS) – the Monarch system

This system consists of an external stimulator, connected by wires to two pads on the forehead. These pads send a signal to the trigeminal nerve. The makers say this nerve is known to play a role in the prevention of seizures. More information is available from the Monarch website.

Information with references

If you would like to see this information with references, visit the Advice and Information references section of our website. See Vagus Nerve Stimulation (VNS) for epilepsy. If you are unable to access the internet, please contact the Epilepsy Action Helpline on freephone 0808 800 5050.


Epilepsy Action would like to thank Gnanamurthy Sivakumar, consultant neurosurgeon at Leeds General Infirmary, for reviewing this information.

Gnanamurthy Sivakumar has no conflict of interest to declare.

This information has been produced under the terms of The Information Standard.

  • Updated May 2016
    To be reviewed May 2019

Comments: read the 5 comments or add yours


I was diagnosed with epilepsy 5 years ago I was put on lamotrigine which didn't work so they then put me on lamotrigine and keppra which also didn't work so they then tried lamotrigine, keppra and epilim chronic and over time took me off the keppra because of really bad side effects, my seizures are still not controlled I am due to see my consultant next month and don't know what to say to them anymore

Submitted by Eibhlin on

Hi Eibhlin

It sounds like you're going through a tough time. If you are in the UK you could ask your consultant about getting referred to an epilepsy specialist centre. Current guidance in the UK says you could be referred to a specialist centre if your epilepsy is difficult to control. This includes if you have tried at least two different epilepsy medicines and are still having seizures, or if you have severe side-effects from your epilepsy medicine. At a specialist centre they may offer you other treatment options such as different medicines, epilepsy brain surgery or VNS. We’ve got more information about specialist centres on our website as part of our seize control campaign.

This information applies if you are in the UK. If you are outside the UK you could speak to one of the international epilepsy organisations for advice.

I hope this information helps. If you have any other questions or want to talk anything through, please feel free to contact us again, either by email helpline@epilepsy.org.uk or the Epilepsy Action Helpline freephone 0808 800 5050. 

Epilepsy Action Advice and Information Team

Submitted by Grace, Epilepsy... on

my daughter has had epilepsy since being a young child she is now an adult, we have never achieved control despite trying numerous combinations of anticonvulsant medication. She has on average 5 seizures a week, cluster seizures and was regularly requiring medical attention in AE due to prolonged seizure activity and status. She had a vagal nerve fitted 14 months ago and it has transformed her life. She still has regular seizures however use of the magnet is generally successful and stops the seizure, her recovery time is much quicker and her quality of life has been improved.

Submitted by Tracey Marshall on


At the moment I am on 1500mg Keppra twice daily and 150mg vimpat twice daily. I have tried a lot of aed`s About 6 yrs ago I had a bad spell of cps. eventually they sorted it but now seems to be starting again. it took the specialist a long time to find something as I have been on so many different aed`s. I am just waiting for a letter to see her again. I have been looking at VNS and I was wondering if it would be suitable for me as when a sz is coming on I always get a kind of warning so I think this may work for me. What does anyone else think.


Submitted by Trevor Haslam on

My son Adam had the vns procedure . I have to say it's changed his life.Hes now much more alert and happier. He had stopped enjoying his life and stopped being my amazing Adam.The vns has brought him back to us.It hasn't just virtually stopped his fits it's given him his quality of life. back. We are so grateful to the Drs and wonderful nurses at the. Queens medical centre and of course to the company that brought us vns. I would recommend this treatment to anyone that is suffering from epilepsy, for us it's been life changing

Submitted by Yvonne lewis on