Fig. 1
![Fig. 1](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs12967-019-1801-y/MediaObjects/12967_2019_1801_Fig1_HTML.png)
a–d Pain intensity (VAS) score, migraine frequency (headache days, total number of attacks) and Pittsburgh Sleep Quality Index (PSQI) score at baseline (preVNS) and follow-up (postVNS) in all patients. Mean values with Standard deviations are presented. “*” Indicate the statistical significance