Evaluation of transcranial direct current stimulation efficiency in prophylaxis of menstrual migraine patients and its relationship with CGRP levels

Introduction: The search for new treatments with higher efficacy and less side-effect profile than the drugs used currently in the migraine prophylaxis has brought neuromodulation options to the foregrund. In this randomized controlled study, Transcranial Direct Current Stimulation (tDCS), one of the non-invasive brain stimulation methods, was applied to patients with menstrual migraine (MM) whose attacks could be resistant to treatment. It was aimed to evaluate the efficacy of treatment by clinical improvement scales and Calcitonin Gene-Related Peptide (CGRP) levels. Methods: Fifty-six female patients between the ages of 18-45 years, including 35 MM, 21 non-menstrual migraine (MM-), were included in this study. Three consecutive sessions of anodal tDCS were applied to the left dorsolateral pre-frontal cortex with an intensity of 2mA for 20 minutes to 29 patients. Twenty-seven patients underwent sham stimulation over the same region. Migraine attack characteristics (frequency, severity, duration), analgesic usage and CGRP levels of the patients were followed up at the baseline and for a month after TDCS. Results: Age of onset (p:0.033) and migraine attack severity were higher in the MM group (p:0.025). After tDCS, in the active group compared to the 'sham' group, the number of attacks per month (p:0.031), the number of days with headache (p:0.004), the use of analgesics (p:0.024) and the severity of attacks (p:0.003) were all decreased. In both MM and MM- groups, the number and severity of attacks and analgesic usage were decreased in those receiving active stimulation (p<0.001 for each). CGRP levels measured by optical densitometry were similar in the active group and the sham group after tDCS (p:0.129). Conclusion: According to our results, tDCS which was shown to be effective in the migraine prophylaxis, can also be used as an alternative treatment option in MM. The absence of changes in serum CGRP levels after stimulation may suggest that tDCS efficacy may point out to a different cerebral electrophysiological mechanism.