Wasade VS, Schultz L, Mohanarangan K, Gaddam A, Schwalb JM, Spanaki-Varelas M. Epilepsy & Behavior 53 (2015): 31-36.


The vagus nerve stimulator (VNS) is a device used to treat seizures that are not controlled with medication alone (“drug resistant” epilepsy). Vagus nerve stimulation was first approved for use in teenagers and adults with partial epilepsy as an add-on to medication in 1997. Initial research studies showed 1 of 3 people with the device for 3 months had at least a 50% decrease in number of seizures. Since then, it has been shown that people with the VNS continue to have fewer seizures over time, but few studies have reported on the effect after more than 5 years of treatment.

This research looks at how people responded to treatment with VNS for drug resistant epilepsy over many years. The study looked at effects on seizure control as well as driving, working, and use of medicine for depression.

Description of Study

  • Medical records of 207 people who were implanted with a VNS at the same epilepsy center between 1997 and 2013 were reviewed.
  • 90 of these people were contacted by telephone to find out how they were doing.

Summary of Study Findings

Seizure frequency, working, and the ability to drive were compared at the time of the telephone survey to what was written in the medical record before the VNS was implanted.

  • Overall, about 7 out of 10 people (68%) had their seizures lessen by at least 50%.
  • Seizure control was similar in people who had the VNS for different lengths of time, for example less than 5 years, 5 to 10 years, and more than 10 years.
  • People surveyed were taking an average of 3 seizure medications before the VNS was placed and 3 to 4 seizure medications at the time of the phone call.
  • About 15% fewer people were still working and driving. This was true in people with and without fewer seizures.
  • About twice as many people were taking medication for depression.
  • 80% said they considered the VNS worthwhile.

What does this mean?

The vagus nerve stimulator can help reduce the frequency of seizures in people with drug resistant epilepsy. This study suggests that the helpfulness of the VNS in reducing seizures lasts over time, even after 5 or 10 years of treatment. People using the VNS do not usually stop having seizures completely and still need seizure medication.

We do not know whether the long-term treatment was due only to the VNS. The information was not compared to a control group of people who did not have a VNS implanted. However, this study provides more information for people with epilepsy and their families to better understand their treatment options.

Health care professionals can use this information to better advise people with refractory epilepsy about treatment options and long-term effects on seizure control and quality of life.

Article published in Epilepsy & Behavior, December 2015

Authored By: 
Katherine Noe MD, PhD
Reviewed By: 
Nathan B. Fountain MD