After a 28-day prospective baseline period using a headache diary to record headache symptoms and any abortive medications used, subjects who meet diagnostic criteria for chronic migraine and don't meet the exclusion criteria will receive rTMS for 4 weeks. The outcome measure will be evaluated at 4 weeks. During the whole trial period, any adverse events are requested to be recorded in the headache diary for analyses. The primary outcome is 50% reduction in the number of days with headache. 50% reduction as assessed by migraine days, moderate/severe headache days, the mean VRS, and conversion to episodic migraine, SGIC, the change from baseline HALT-28, HIT-6, and MSQ v2.1, are used as secondary outcome measures for exploring other benefits associated with treatment.
