It’s hard to know in advance how someone with epilepsy will respond to VNS therapy.
Successful VNS therapy reduces the number of seizures people have and, sometimes, how long they last. It’s unlikely to stop seizures completely.
Studies show that about one-third of people treated with VNS experience a major improvement in seizure control. One-third experience some improvement, and one-third continue to have seizures as before.
Even when people respond well, improvement usually takes time. It isn’t likely to happen immediately after the doctor implants the device. Several months may go by before there’s any change, followed by a slow but steady improvement.
However, seizure control is not the whole story for this type of treatment. For reasons that are still not well understood, VNS therapy appears to have some other effects as well.
Studies find that many people who have had the implant say they feel better, even if their seizures continue. They say they feel better after a seizure, are in a better mood, feel more alert, have better memory and fewer emergency room visits.