Vagus Nerve Stimulation (VNS)
Your doctor has suggested Vagus Nerve Stimulation (VNS) as an extra treatment to reduce the number of seizures you or your child has as well as how long they last. Either your anticonvulsants don’t work well enough to control your seizures, or there are side effects that are not being tolerated.
With this therapy, a mild electrical signal can be sent to a special nerve that carries information to the brain. This nerve is called the vagus nerve. The vagus nerve is one of the main communication lines from the major organs of the body to the brain. Most of the signals that go to the vagus nerve in the neck are sent upward to the brain.
Parts of the VNS system
Two parts of this system must be placed inside the body during surgery. These 2 parts are shaded in the table below. This won’t require surgery on the brain. Your surgeon will explain more about this during a clinic visit. You should plan on staying in the hospital after surgery. You will be sent home the next day.
What is it? |
Where is it? |
What does it do? |
Pulse Generator or Stimulator |
Under the skin on the left side of the upper chest |
Main component of VNS system; sends signals through electrodes of the VNS lead to the brain |
| VNS Lead | Attached to the left vagus nerve on the left side of the neck |
It holds the electrodes; it's a flexible, insulated tube |
| Computer | Outside the body | Contains VNS therapy software; allows someone to change settings on the pulse generator |
| Programming Wand | Outside the body | Allows doctor or nurse to change settings through the skin |
| Magnet | Outside the body | Allows you to manually "stimulate" the generator; to be used at the start of a seizure or during one to stop or shorten the seizure |
Pulse Generator or Stimulator Settings
The doctor will decide how to program the device so that it works best for you or your child. There are settings for both continuous (“around the clock”) and magnet (“on demand”) stimulation. Any changes to the settings will be made in the hospital or clinic.
Benefits of VNS therapy
VNS is not a cure for epilepsy. It also does not work for everyone. Yet, about one-third of patients with VNS have a dramatic improvement in seizure control. One-third will have a good improvement. Another one-third have little or no change in seizure control. We are not able to predict how you or your child will respond, but many patients have had some benefits as listed below.
- less severe or shorter seizures
- shorter or less severe symptoms after the seizure ends
- more alert overall, improved memory and thinking
- some eventually are able to reduce the dosage of their seizure medications
- very few patients are able to stop medications completely
Side Effects
You may feel side effects at first from the VNS, but they will most likely become less noticeable over time. The most common side effect is hoarseness. The other three most common side effects are sore throat, shortness of breath, and coughing. These problems mostly occur only during stimulation. If these symptoms are non-stop or uncomfortable, let your doctor know.
Other side effects that may be related to the VNS system:
- Lack of coordination
- Inability to sleep
- Indigestion
- Difficulty swallowing
- Nausea
- Pain
- Vomiting
- Throat spasms or tightness
- Throat inflammation
- Tooth pain
- Hiccupping
- Facial flushing
Call your doctor right away:
- if you or your child develop any of these symptoms.
- if stimulation becomes painful.
- if any new symptoms develop that you feel are because of stimulation.
About the Magnet
There are 3 main reasons to use the magnet. We will also tell you how to use the magnet for each reason.
1) Stop a seizure
This is the most common use for the magnet.
How?
If you or your child feels an aura or a seizure starting, start stimulation by
holding the magnet on the pulse generator for two seconds. If the seizure
does not stop or slow down, you can repeat this one, two, or three minutes
after the first use. The magnet may also be used in the middle of a seizure.
2) Temporarily turn OFF the pulse generator
This is done:
- When you or your child plan to sing or speak in public (if stimulation causes a change in your voice).
- When eating (if there are swallowing problems).
- If stimulation becomes painful or uncomfortable.
How?
Place the magnet over the pulse generator. Hold it there, or tape it in place
for as long as you want the stimulation stopped. As soon as the magnet is
removed, the regular stimulation cycle will restart.
3) Check if the pulse generator is working
Your doctor will do this at an office visit.
Cautions about handling the magnet
- Do not drop the magnets. They can break if dropped on a hard surface.
- Carry a magnet with you at all times. Show caregivers how and when to use the magnet.
- Never store magnets near credit cards, computers, computer discs, watches, or other magnets. Keep them at least 10 inches away. The reason for this is the magnet may cause damage to these items.
- Do not sleep with the magnet on your wrist. Moving around during the night can place the magnet over the generator for long periods of time by mistake.
Avoid excessive vagus nerve stimulation. This happens when using the magnet for more than four hours of constant stimulation.
Using other magnets
Only the magnet given to you from the Cyberonics Company should be used with your VNS. If you lose or break your magnet, order another one from Cyberonics. In an emergency, you can try other strong magnets. The use of other magnets will not harm the device.
Hazards
| Environmental hazards | Medical hazards | |
| Unsafe | Strong magnets, hair clippers, vibrators, loudspeakers, and similar electromechanical devices can cause the puls generator to start suddenly
Transmitting antennas may interfere with the VNS
|
Treatment with radiation, colbalt machines, and linear accelerators may damage the pulse generator
with a body coil in transmit mode
magnet output setting) must be turned off before MRI and surgery.
diathermy, electrocautery, and extracorporeal shockwave lithotripsy may damage the pulse generator
the operation of cardiac pacemakers and implantable defibrillators treatment since heat may be concentrated by the device |
More Safe |
Small appliances like microwave ovens, toasters, hair dryers, electric shavers should not affect the pulse generator
Cellular phones do not affect the pulse generator
Properly working electrical ignition systems and power transmission lines should not affect the pulse generator
Antitheft devices and metal detectors should not affect the pulse generator |
Most routine diagnostic procedures should not affect the pulse generator
Special positioning during mammography may be needed for a clearer image
|
About the Pulse Generator Battery
Battery life ranges from 6.5 to 10 years if used at normal settings. It will lose its power over time. When this happens, it will begin to stimulate differently. You may notice an increase in the number of seizures, how severe they are, and how long they last. Seizures may increase to the level they were before the VNS was placed. Call your doctor if you suspect this has happened. Your doctor will discuss with you the benefits of VNS and whether the pulse generator should be replaced.
If you have questions about VNS and your seizure control, ask your neurologist.
The information provided should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Any duplication or distribution of the information contained herein is strictly prohibited.
Last Updated: 01/07/2013
Copyright © 01/07/2013 University of Wisconsin Hospitals and Clinics Authority. All rights reserved. Produced by the Department of Nursing. HF#6143
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