Our aim was to compare seizure frequency reduction between traditional and t-VNS

We conducted a systematic review following the PRISMA guidelines. Included were clinical and/or randomized trial articles indexed by Embase and Pubmed, with the keywords: “drug-resistant epilepsy” or “refractory epilepsy” and “vagus nerve stimulator”. We performed a meta-analysis, considering treatment success as ≥ 50% of seizure frequency reduction. Statistical analyses were weighted for population size. We performed Mann-Whitney test for between-group and Wilcoxon test for within-group analyses.

Eighteen studies were included (13 traditional, 5 t-VNS), with a total of 1383 patients, with a mean age of 31.27 ± 8.71 years and median follow-up assessment of 12 months (range, 3.5–36). The median success rate for the traditional and t-VNS groups were 49.2% (range, 28–100) and 28% (range, 0–54), respectively (P < 0.0001), with adherence >70% to t-VNS. High variability was observed within the traditional VNS studies (P=0.002), but not in t-VNS. The most common reported side effects from t-VNS were ear pain, dizziness, and headache while traditional VNS was most associated with cough and dysphonia.