To study the Efficacy of repetitive transcranial magnetic stimulation (rTMS)in chronic migraine with vestibular symptoms, An open labelled randomized sham control study.

Migraine is a disease that stays  lifelong . It needs abortive

treatment for acute headache and prophylactic treatment for recurrent headache. Experimental and human

research have shown that abnormality of trigeminovascular

system, brainstem and cerebral cortex are involved in  migraine pathogenesis. It has been shown experimental studies that  single pulse of transcranial magnetic stimulation (TMS) can

interrupt cortical excitability in depression(6,7) . This finding has opened the gate for evaluating the  TMS for acute migraine treatment.High-frequency rTMS may increase the cortical activity found in

controlling pain(8)  or  decrease cortical excitation(9). So this can be used in migraine prophylaxis. Repetitive Transcranial magnetic stimulation (rTMS) is a painless, easy to deliver, affordable neurophysiological technique widely used as treatment. It produces sub or suprathreshold currents by electromagnetic induction, in the cortex. There are two types of rTMS modalities are available. One is high-frequency (HF-rTMS) stimulation (>1 Hz).It increases excitability of motor cortex of the stimulated area. Second is low-frequency (LF-rTMS) stimulation (⩽1 Hz) .It usually causes a reduction in cortical  excitation .Coil position during rTMS session is defined by the area where motor threshold (MT) is recorded. MT is defined as lowest transcranial magnetic stimulation intensity needed to produce a motor evoke potential (MEP) of amplitude >50µv in at least 6 of 10 trials. The rTMS role has been proven in other disease like depression, migraine prophylaxis with minimal side effects. Various studies has shown mixed results about rTMS role in migraine prophylaxis. In 27 migraine patients who are given Low-frequency rTMS shown improvement of headache frequency but without significant difference with respect to  sham stimulation group(9). There are two studies with High-frequency rTMS. A study, involving 11 migraine patients , with 6 patients receiving 400 pulses of rTMS  at 20 Hz at 90 % of MT for 12 sessions  and five patients received sham stimulation(8). Frequency of headache, rescue pill intake decreased significantly. In  rTMS

group  this effect persisted for 8 weeks . This effect of rTMS

was not shown in other studies. Low-frequency rTMS has was not effective when two trains of one Hz ,500 pulses was given  for

five contineous days(9) . An open-labeled trial shown ten Hz

rTMS consisting of 600 pulses in ten trains on alternate

days for three days was given(10). This trial shown efficacy in decreasing headache frequency by more than 50 % among 80 % of patients. This benefit stayed for four weeks . These variability about effect of rTMS as prophylaxis in chronic migraine is needed to be addressed.