Fig. 2: Effect of eTNS alone or combined with anti-migraine or anti-epileptic medication on quality of life outcomes.

The summary effect size and its precision (95% confidence interval) are indicated by the diamond, with the dotted line indicating the dispersion of the true effect (i.e., 95% prediction interval). All post-assessment time points were <24 h after the last eTNS session, with the exception of An et al. (2020), which was conducted during treatment period at week 8 of stimulation. A positive effect indicates an effect in favor of the active eTNS intervention. Legend. FLZ Flurazine, NM Nimesulide.