Fig. 5

Results of the available randomized controlled trials comparing transcranial direct current stimulation to sham procedure. The list is taken from the guidelines of clinical trials of neuromodulation devices for the treatment of migraine in adults [14]. More detailed quantitative reports are provided in Supplemental file 1. Green circles indicate that tDCS was entirely superior to sham, amber circles that tDCS was partially superior to sham, red circles that tDCS was note superior to sham; cells were left empty if outcomes were not reported