Frequently Asked Questions

Do small electrical appliances, cellular phones or metal detectors affect VNS?

According to the manufacturer, properly operating microwave ovens, toasters, hair dryers or other electrical appliances should not affect the pulse generator. Based on testing to date, cellular phones do not affect the pulse generator. Metal detectors at airports and other places should not affect the pulse generator.

What are the hazards, if any, of other kinds of medical treatment or tests when someone has a VNS implant?

There are some important safety issues associated with other types of treatment that people with VNS implants should be aware of.

People with the VNS implant should not have any kind of diathermy (sometimes called deep heat) treatment because it may cause the implant to heat up and damage nerves and tissue.

Short wave diathermy, microwave diathermy or therapeutic ultrasound diathermy are all types of treatment that should not be used. Cyberonics, the company that manufactures the VNS system, emphasizes that, while it's not aware of any injury from diathermy use, there is a significant risk that all patients should be aware of.

Diathermy is not used as a treatment for seizures. It aims to promote healing by heating deep muscular tissues with high-frequency electrical currents. It is commonly used to relieve pain, stiffness and muscle spasms, reduce joint contractures, reduce swelling and pain after surgery, or to promote wound healing. Diathermy treatments may be used by many different health care providers, including dentists. This therapy may also be used in ways that provide little to no heat or during certain surgical procedures.

Use of diathermy for any reason by someone with a VNS implant may cause the implant to heat up, causing pain and temporary or permanent damage to surrounding nerves and tissue. Such effects are potentially dangerous and may include loss of vocal cord function, or even death, if veins or arteries in the neck are damaged. Diathermy treatments may also affect the functioning of the implant.

Application of diathermy treatment anywhere in the body, not just where the implant is located, may cause damage. The risk exists whether or not the treatment is used to deliver heat or no heat, and whether or not the VNS device is on and delivering electrical stimulation, or off and not delivering stimulation. Even if the battery has been removed, the risk remains so long as the wires are still in place.

On the other hand, the manufacturer says that most routine procedures, such as having an ultrasound or an x-ray, should not affect the VNS. Still, anyone with a VNS implant should be sure to tell health professionals about the implant and where it's located, and also show their manufacturer-supplied identification card to all doctors, dentists, nurses, physical or sports therapists, rehabilitation providers, chiropractors or any professional providing treatment of any kind. The company has a clinical/technical support telephone number for health professionals to call if they have any questions about treating someone with a VNS. That phone number is (800) 332-1375 ext. 330 or ext. 337.

If someone with VNS is going to have an MRI (magnetic resonance imaging) scan, special precautions should be taken. These should be discussed with the doctor in advance and the technicians giving the MRI should also be aware of the VNS implant. Only certain MRI scanners should be used and the device should be shut off temporarily for the MRI scan. For more information, consult your neurologist.

Does VNS therapy cause sleep disturbances?

There have been reports that some people using VNS therapy have pauses in regular breathing (sleep apnea) and other sleep interruptions when the device turns on during sleep. If the patient or family members notice this effect, the doctor should be told.

If a magnet doesn't prevent a seizure from coming on, does that mean the VNS isn't working properly?

Possibly. Or it could mean that the settings may need to be changed. Someone with a VNS implant who has previously been able to prevent seizures by using a magnet should tell the doctor if it appears to have stopped working. On the other hand, the extra stimulation that the magnet produces will not stop a seizure for everyone.

Does the implant have to be replaced after a period of time?

The manufacturer says the device can last up to 12 years, depending on the model, the stimulation settings used, and how the electrodes and vagus nerve work together over time. The battery may have to be replaced after six years or sooner. It's a good idea to check with your doctor from time to time about battery life and when a replacement may be needed.

Where can I get more information about VNS therapy?

Check with your doctor or contact the Epilepsy Foundation at (800) 332-1000. Also, the manufacturer has made available a VNS Patient's Manual. This is a PDF file from the manufacturer's website -- Requires Adobe Acrobat Reader to view.

If you or a family member are thinking of starting VNS therapy, it may be helpful to talk to other people living with VNS. The Epilepsy Foundation in your community -- or your doctor -- may be able to put you in touch with other VNS patients.