Prophylactic treatment in menstrual migraine: A proof-of-concept study

• Cathodal tDCS (ctDCS) decreases cortical excitability.
• Repeated ctDCS applied before the menstruation decreased the number of migraine attacks compared to baseline, but not to sham.
• Visual cortical excitability decreased in the cathodal group.

The present study aimed to investigate the efficacy of repetitive cathodal direct current stimulation (rctDCS) over the visual cortex as a prophylactic treatment in patients with menstrual migraine. 20 female patients were recruited in this double-blind, placebo-controlled study and were assigned to receive either cathodal or sham stimulation. Over 3 menstrual cycles, tDCS with 2 mA intensity and 20 min duration was applied to the visual cortex of the patients, in 5 consecutive sessions 1–5 days prior to the first day of their menstruation. The primary endpoint of the study was the frequency of the migraine attacks at the end of the treatment period, however, additional parameters, such as the number of migraine related days and the intensity of pain were also recorded 3 months before, during and 3 months post-treatment. Visual cortex excitability was determined by measuring the phosphene thresholds (PTs) using single pulse transcranial magnetic stimulation (TMS) over the visual cortex.Sixteen patients completed the study. A significant decrease in the number of migraine attacks (p = 0.04) was found in the cathodal group compared to baseline but not compared to sham (p = 0.053). In parallel the PTs increased significantly in this group, compared to the sham group (p < 0.05).Our results indicate that prophylactic treatment with rctDCS over the visual cortex might be able to decrease the number of attacks in patients with menstrual migraine, probably by modifying cortical excitability.