Design
headache
This prospective, multi-centre, single-blind, randomised, and sham-controlled study consisted of a 28-day baseline period, a 28-day treatment period, and a subsequent follow-up period. Patients were randomised at the end of the baseline period to receive either active or sham tDCS treatment using a block randomisation technique with block sizes of ten participants.Migraineurs kept headache diaries throughout the study period using the German headache diary. Moreover, we acquired magnetic resonance images from each patient at the baseline visit (BL), shortly after the stimulation period (F1) and about five months after the stimulation period (F2).The ethics committee of Canton Zurich, Switzerland, approved the research project (registered at clincicaltrials.gov, NCT03237754, full date of first trial registration: 03/08/2017), which we conducted at the University Hospital Zurich from 2016 to 2020. All methods were performed in accordance with the relevant guidelines and regulations.We did not predefine the sample size because no pilot data were available, but we aimed for 50 patients and 50 healthy controls (HC). The available data determine the sample size. A previous article discusses the clinical results