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Updated: Aug 21, 2026
Vagus Nerve Stimulation As an Adjunctive Neurostimulation Tool in Treatment-resistant Depression
Published on: January 7, 2019
Vagus nerve stimulation therapy: 5-year or greater outcome at a university-based epilepsy center
Marianna V Spanaki1, Linda S Allen, Wade M Mueller
1Department of Neurology, Medical College of Wisconsin, 9200 W. Wisconsin Avenue, Milwaukee, WI 53226, USA. mspanaki@mcw.edu
Objective:
This retrospective study documented long-term outcome of patients receiving vagus nerve stimulation (VNS) therapy for pharmacoresistant epilepsy.
Methods:
Medical charts of 28 patients implanted for 5 years or longer were reviewed for changes in seizure frequency after 1 year of VNS therapy and at follow up, which ranged from 5 to 7 years. Numbers of antiepileptic drugs (AEDs) taken by the patients were also computed at 1 year and follow up. One patient had died and one had discontinued VNS therapy; data were available for 26 patients.
Results:
The median percent change in seizure frequency from baseline increased from -28% (P = 0.0053, Wilcoxon signed-rank test) at 12 months to -72% (P < 0.0001) at follow up. Some patients whose seizure frequency was not reduced during the initial 12 months of VNS therapy did experience reductions in seizure frequency during the follow-up period.
Conclusion:
In this retrospective study, the effectiveness of VNS therapy increased over time. Physicians should be aware that response to VNS therapy may be delayed for some patients.
