Vagus nerve stimulation is treatment sometimes used for people who have medication resistant epilepsy – when seizures aren’t fully controlled with medication. It is a procedure that involves implanting a pace-maker-like device that stimulates the vagus nerve with regular electrical impulses.
Some people may not be suitable candidates for epilepsy surgery, and vagus nerve stimulation is a form of neurostimulation that offers another method to manage seizures. It has been proven to be a safe and effective method which can be combined with medication therapy to reduce seizures.
The vagus nerve
There’s one vagus nerve on each side of your body, running from the base of your brain, down your neck to your chest and abdomen. The vagus nerve 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 VNS?
VNS Therapy is mild intermittent electrical stimulation of the vagus nerve. 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 seizures that are unable to be controlled with antiseizure medication.
How does it work?
A pacemaker like generator is implanted in the chest and a lead is attached to the vagus nerve, which delivers electrical impulses to this nerve at regular intervals. If people get a warning or aura of an impending seizure, they can wave a magnet over the pacemaker to activate the electrical stimulus, which may prevent or reduce the intensity of the seizure.
What have studies shown?
Response and seizure freedom rates increase over time with VNS therapy. 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%. People also report a reduction in seizure severity as well. Less than 5% of people become seizure free and up to 25% of people do not experience any positive effect of VNS at all (Englot et al 2016).
Long-term follow-up studies show seizure control improves over time and is maintained.
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 general quality of life
- improvements in mood – VNS is also used to treat depression
- Some people may be able to reduce the medications they take
- Safety risks associated with seizures, including SUDEP, are reduced as well
- People who have an “aura” can use the VNS magnet to abort or reduce the severity of an oncoming seizure.
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 about VNS Therapy, 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.
Epilepsy Action Australia is the exclusive distributor of LivaNova VNS Magnets in Australia. Buy online here