Vagus nerve stimulation (VNS) for epilepsy

Share on Pinterest

VNS therapy is a treatment option for epilepsy.

The vagus nerve runs from the brainstem to many organs, including the heart, lungs, and those of the digestive system.

The nerve communicates with the brain, providing feedback about the conditions of the body.

In VNS therapy, a doctor places a VNS stimulator device inside a person’s body. This sends electrical pulses through the vagus nerve to the brain.

The device sits in the left side of the chest with an electrode that attaches to the left vagus nerve in the neck.

It sends mild electrical pulses at regular intervals through the nerve to the brain. Experts believe this helps to regulate electrical activity in the brain.

VNS may help to:

• reduce the amount, length, and severity of seizures
• reduce recovery time after a seizure
• prevent a seizure while it is happening

There are three main types of VNS devices currently available:

• Standard model: These are the original devices, which may deliver pulses every five minutes for 30 seconds.
• AspireSR model: Offers an auto-stimulation feature, which may help people with seizures that increase their heart rate.
• SenTiva model: The newest VNS model offers auto-stimulation, more specific programming options, and can identify if a person is lying down flat after a seizure.

All the devices have a handheld magnet to provide extra stimulation during a seizure.

Which types of seizures is VNS suitable for?

According to the Epilepsy Foundation, VNS may be suitable for people with focal, or partial, seizures that have not responded to at least two types of seizure medications.

The VNS procedure may be suitable for the following people:

• those who have refractory, or drug-resistant, epilepsy
• those whose seizures cannot have treatment by surgery
• adults and children aged 4 years or over
• those with focal seizures, although it may also help some types of generalized seizures and Lennox-Gastaut syndrome

People who may not be suitable for VNS include:

• those with significant breathing or heart problems or any health condition that VNS may worsen
• those with only one vagus nerve
• those with abnormal heart rates, or arrhythmias, as they will not be able to use auto-stimulation settings for a VNS device
• those with seizures that are not epileptic, such as psychogenic nonepileptic seizures (PNES)

Doctors can perform tests before the surgery to help determine whether a person is likely to improve with VNS therapy.

These tests may include an electroencephalogram (EEG) to examine seizure activity. Sometimes, doctors use an external stimulator to determine whether a person is likely to improve.

Before VNS surgery, people will usually receive a general anesthetic. A neurosurgeon will carry out the procedure. The surgery may take around 45–90 minutes.

The surgeon will make a small incision into the upper left chest area to insert the VNS device. They will make another small incision into the left lower neck to insert thin wires that attach the VNS device to the vagus nerve.

Getting a VNS implant is usually an outpatient procedure, and a person will not have to stay overnight. People may experience some pain after the surgery, but pain-relief medication can help ease this.

A doctor may activate the device at the time of surgery or wait 2–4 weeks after the procedure.

A person will have a handheld magnet that they can wave over the VNS device to create extra stimulation or to turn stimulation off.

Possible side effects of VNS therapy may occur during nerve stimulation. These include:

• throat discomfort
• hoarse voice
• cough
• difficulty swallowing

Possible risks with VNS surgery include:

• infection
• inflammation or pain at the site of the incision
• nerve damage or constriction

People may not experience immediate results from VNS. It can take up to two years for VNS to affect seizures.

The battery in the VNS device may last from 1–15 years. When the battery expires, a surgeon will replace the device by opening the existing incision, which is a less invasive procedure than the original surgery.

In some cases, people may initially be aware of the device but, over time, will usually not feel it.

VNS may not be effective for everyone and may not stop seizures completely. A person will still need to take anti-epileptic drugs (AEDs) alongside VNS — although if VNS is effective, they may be able to reduce medication.

People can keep the magnet close to them and may find it helpful to wear it on the wrist or around the waist. A person or those around them can use the magnet if they have a seizure.

This section answers some common questions about VNS therapy for epilepsy.

Is VNS a major surgery?

VNS is not a major surgery as it involves small incisions into the chest and is usually an outpatient procedure.

People will usually have a general anesthetic for the procedure.

Can I have an MRI scan if I have VNS therapy?

People will need to let any healthcare professional know they have a VNS device before having an MRI scan.

Doctors may need to take certain precautions to ensure the scan is safe.

Can I go through security at the airport with a VNS device?

Security scanners at the airport will not usually cause problems with a VNS device, but a person will need to ask security staff to avoid waving a security wand over their body.

People can show their VNS identity card or a doctor’s letter. Security staff can perform a pat-down check instead.

VNS therapy is an implanted device that attaches to the vagus nerve to provide electrical pulses to the brain. This helps regulate electrical brain activity and may help to reduce seizure activity.

People will need to continue taking AEDs alongside VNS therapy. VNS therapy may be suitable for people if medication alone has not been effective or if epilepsy surgery is not an option.