Purpose: Transcranial direct current stimulation (tDCS) may have therapeutic potential in the management of migraine. However, studies to date have yielded conflicting results. We reviewed studies using repeated tDCS for longer than 4 weeks in migraine treatment, and performed meta-analysis on the efficacy of tDCS in migraine.
Methods: In this meta-analysis, we included the common outcome measurements reported across randomized controlled trials (RCTs). Subgroup analysis was performed at different post-treatment endpoints, and with different stimulation intensities and polarities.
Results: Five RCTs were included in the quantitative meta-analysis with a total of 104 migraine patients. We found a significant reduction of migraine pain intensity (MD: − 1.44; CI: [− 2.13, − 0.76]) in active vs sham tDCS treated patients. Within active treatment groups, pain intensity and duration were significantly improved from baseline after tDCS treatment (intensity MD: − 1.86; CI: [− 3.30, − 0.43]; duration MD: − 4.42; CI: [− 8.11, − 0.74]) and during a follow-up period (intensity MD: − 1.52; CI: [− 1.84, − 1.20]; duration MD: − 1.94; CI: [− 3.10, − 0.77]). There was a significant reduction of pain intensity by both anodal (MD: − 1.74; CI: [− 2.80, − 0.68]) and cathodal (MD: − 1.49; CI: [− 1.89, − 1.09]) stimulation conditions.
Conclusion: tDCS treatment repeated over days for a period of 4 weeks or more is effective in reducing migraine pain intensity and duration of migraine episode. The benefit of tDCS can persist for at least 4 weeks after the completion of last tDCS session. Both anodal and cathodal stimulation are effective for reducing migraine pain intensity.