Vagus nerve stimulation is another treatment used for people with poorly controlled epilepsy, most often used when other treatments haven’t worked. It is a procedure that involves implantation of a device that stimulates the vagus nerve with electrical impulses.
There’s one vagus nerve on each side of your body, running from your brainstem through your neck to your chest and abdomen. The vagus nerve is one of the nerves that are connected directly to the brain. It is responsible for control of muscles for swallowing, coughing and voice and feedback from the heart, lung, stomach and upper bowel to the brain. The left vagus nerve mostly receives input from the body to the brain, with very few heart connections, making the left vagus nerve most suitable for this procedure.
What is it?
VNS Therapy is a mild intermittent electrical stimulation of the vagus nerve that runs through the neck and carries information to the brain. In some people with epilepsy this can reduce the frequency and intensity of seizures.
VNS Therapy is for use as an add-on therapy to help reduce the number of seizures in people whose epilepsy is predominantly focal seizures (with or without progressing into tonic clonic seizures) or generalised seizures that are unable to be controlled with antiepileptic medications.
How does it work?
A pacemaker like generator implanted in the chest and a lead is attached to the vagus nerve, which delivers electrical impulses to this nerve at regular intervals. The device is programmed to deliver a regular stimulus to the vagus nerve. If people get a warning or aura before a seizure begins, a magnet can be used to activate the stimulus, which may prevent or reduce the intensity of the seizure.
What have studies shown?
Approximately one third people have good improvement in seizure control with the number of seizures reducing by at least 50%, and one third of people experience a seizure reduction between 30 and 50%. Long-term follow-up studies show seizure control improves over time. Less than 5% of people who become seizure free and up to 25% of people do not experience any positive effect of VNS at all (Seizure 2011).
Are there other benefits?
Many people have reported benefits other than a reduction in seizure frequency. These benefits include an improvement in alertness, memory, energy levels and mood. Some people may be able to reduce the medications they take.
Vagus nerve stimulation may be of additional benefit for people with epilepsy who suffer depression because it is also used to treat hard-to-treat depression that hasn’t responded to typical therapies.
Safety risks associated with seizures are reduced as well.
What are the side effects?
VNS may cause side effects in some people. The most common include:
- Changes in voice
- Hoarseness or throat discomfort
- Tingling or pain in the throat or neck
These effects are generally related to the stimulation settings and diminish over time or after a change in the stimulation settings.
Less common side effects include:
- Shortness of breath, reduced exercise tolerance
- Difficulty sleeping, snoring and apnoea during sleep
- Difficulty swallowing
- Pain or infection where the device was implanted through the skin
As with any surgery, there is a small risk of infection and bleeding.
Having a VNS implanted does not mean medications will be stopped. It is usually used in conjunction with medications.
If you would like to know more speak to your specialist.
Vagus nerve stimulation is not for everyone and you should check with your doctor about the suitability of this procedure for you.
For more information go to:
What’s it like? (includes video)