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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 find that your seizure control slowly improves over time. A study involving 347 children found that seizure frequency and severity gradually improved between 6 months and 2 years after the children had the VNS system fitted. Most people don’t become seizure free with VNS therapy.  

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.

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?

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. The VNS Therapy website has more information about MRI safety.

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 more information about VNS safety precautions on the VNS Therapy website.

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 onthe VNS Therapy website by 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. If you are unable to access the internet, please contact our Epilepsy Action Helpline freephone on 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 11 comments or add yours


Where can i order replacement magnet for my son's VNS?

Submitted by Tracy Roe on

Hi Tracey

You just need to ask at the clinic where the VNS was fitted. They will provide a replacement for you.



Epilepsy Action Helpline Team

Submitted by rich on

Hi just want to know after the operation how long after can you have a shower.

Submitted by Sarah on

Hi Sarah

We can’t answer that. It is something the surgeon or epilepsy nurse would be able to tell you. Or if it’s just a general enquiry you could always ask in our online community forum4e. A number of people in there have had the VNS fitted.

I hope that helps.



Epilepsy Action Helpline Team

Submitted by Cherry-Epilepsy... on

I'm on my second VNS and also need all my medication 3 different anti-convulsant tablets. But can't describe what a difference it has made. Thanks to Prof. M. Reuber at Royal Hallamshire Hospital Sheffield.

Submitted by A DAY on

Our son ,Tahl is 10.5 years old .Before five years , Tahl for a first time had a surgery and vagus nerve stimulator implanted in a hospital in Israel .After two years ,Tahl had a second surgery of replacing stimulator due to of internal battery and now after routine inspection in hospital by neurologist was found a low lead impedance of stimulator by external analyzer .The neurologist informed us that there is necessity to replace generator or lead . We want to know what a reason of low lead impedance ,does it have an influence on functioning of stimulator and what a damage it can cause ? Thank you for an answer.

Submitted by Slava Leifman on

Is VNS suitable for someone who has occasional sleep seizures. Thank you

Submitted by Gail Johnson on

Hi Gail, 

VNS can be used for most seizure types. It’s an option for some people with difficult to control epilepsy https://www.epilepsy.org.uk/info/treatment/vns-vagus-nerve-stimulation

If we can be of any more help, please feel free to contact us again, either by email helpline@epilespy.org.uk  or phone the Epilepsy Action Helpline freephone 0808 800 5050. Our helpline is open Monday to Friday, 8.30am until 5.30pm. 



Epilepsy Action Helpline Team

Submitted by rich on

I have suffered Grand Mal Epilepsy since 2003, i am now 34 years old. I stopped taking my medicine completely since Dec of last year. Due to the side affects. I have only had 3 seizures since, poss due to lack of sleep and not eating enough. Could I poss be a candidate for a Vagus nerve stimulator to be fitted. Can I ask for a refferal via my G.P? How long can you go without being considered an epileptic, i.e how long do you have to be seizure free. I have been unable to work and am not allowed to drive. I want my life back. Could the Vagus nerve stimulator make me seizure free?

Submitted by Keith Oakes on

Hi Keith,

There are strict criteria for having VNS therapy on the NHS. It’s restricted for when other treatments haven’t worked or haven’t been suitable. You would need to have tried several different medicines and be unsuitable for epilepsy brain surgery. If you think you might be eligible you could speak to your epilepsy specialist. If you’re not seeing a specialist at the moment you could start by speaking to your GP. The VNS therapy doesn’t stop seizures completely. But for some people it makes them fewer and less severe.

The longer it is since your last seizure, the less likely it becomes that you will have another. However, sometimes people can be seizure free for years and then have another seizure. Everybody is different so it’s impossible to say at what point someone will never have another seizure.

When you can re-apply for your driving licence depends on the type of seizures you have. For most people it is when you have been seizure free for 12 months, but there are some exceptions. And we have some more information on the driving rules on our website.  

We also have some hints and tips on our website to help with seizure control and finding work that you might find useful.



Epilepsy Action Helpline Team

Submitted by rich on

I had 3 brain surgeries prior to getting the VNS and now have the second one because the battery went out. It reduced my siezures from about 100 per month to about 30. My current one needs replacement soon as the battery is going out. I really am grateful for the device.

Submitted by KWgreulich on

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