The Food and Drug Administration (FDA) approved the use of the Vagal Nerve Stimulator (VNS) for the treatment of certain kinds of epilepsy in 1997. It is a pacemaker-like device that works by intermittently sending a small electrical current to a nerve in the neck called the Vagus Nerve. The electrical impulse travels back to the brain where it helps to reduce and possibly stop seizures.
What kind of epilepsy does the VNS treat?
The answer to this is not entirely known. Studies are being done to look into several kinds of epilepsy. However, the FDA has only approved its use for the treatment of partial seizures. If you are not sure what kind of epilepsy you have, you should talk with your doctor.
Who puts the VNS in?
Generally, a neurosurgeon places the device.
Will I have a scar?
The VNS has two parts. One part is the generator or battery pack. The second part is composed of platinum wires which run from the generator and attaches to the vagus nerve. Because there are two parts, there are two incisions. One is used to place the generator, and the second is used to place the wires. The incisions are small, and heal very well. In most people, the scar is unnoticeable several months after the surgery.
Will I be able to see the generator?
Since all people are different, there are different body types. In some, the device cannot be noticed. In others, a slight bulge can be seen in the area where the VNS generator was placed.
How well does it work?
The results of studies have shown that 1/3 of patients have a reduction (> 50%) in seizures, 1/3 have a smaller reduction in seizures (< 50%), and 1/3 experience no change in their seizures.
What are some of the side effects?
Most people get used to the stimulation, and do not even notice it. However, the stimulator is programmed to send an electrical impulse once every 5 minutes. When the stimulation occurs, some people experience temporary hoarseness of voice. This is not painful, but can be a nuisance. Other side effects include coughing during the stimulation. In most people, this only happens when the device is first turned on. As a person becomes accustomed to the VNS, this goes away.
How do I know if the VNS is working?
If a person does not experience any sensation during stimulation, they may only be aware that the device is working when their physician checks it. Each time you visit your doctor, he or she will 'interrogate' the VNS using a computer. It is a completely painless process that allows the physician to both check the VNS and change settings, if needed.
How long will it take for the VNS to work?
Since everyone is different, this is a harder question to answer. However, when the VNS is first turned on, it is activated at the lowest setting. The settings are gradually increased over a period of 4-8 weeks to reach the 'therapeutic range.' The 'therapeutic range' refers to the settings that are needed to reduce seizures. Once in the therapeutic range, there can be a delay until the effects are seen. The delay can be as long as six months.
Will I be able to stop my medicines once I have a VNS?
No. All patients stay on at least one medication in addition to the VNS. However, the dose of medications may be reduced once the seizures are better.