Including recent FDA approvals of several calcitonin gene-related peptide (CGRP) receptor antagonists, advances in pharmacologic therapy for the prevention of migraine continue to emerge. In general, CGRP inhibitors offer moderate efficacy for migraine prevention, but some patients may be unable to tolerate these therapies due to a wide range of adverse effects. As a result, various novel, non-pharmacologic interventions for migraine are being investigated in clinical trials.
“Despite recent advances in new pharmacologic therapies for migraine prevention like CGRP inhibitors, there continues to be an unmet need for using novel device-based interventions for preventing migraine attacks,” says X. Michelle Androulakis, MD. “One type of non-invasive approach currently being investigated is the use of transcranial direct current stimulation (tDCS). This type of brain stimulation offers several unique advantages to pharmacologic options, including portability for potential home use and a well-established safety and tolerability profile.”
Brain Stimulation for Migraine?
Research indicates that sustained and repeated tDCS sessions may play a role in migraine prevention by provoking cumulative and long-lasting neuroplastic changes in the cerebral cortex. “Many studies have used tDCS for different neurological disorders, such as multiple sclerosis, stroke, dementia, and pain,” Dr. Androulakis says. “However, these analyses are often limited by the number of sessions delivered. Studies suggest that using repeated tDCS stimulation with longer sessions may have better efficacy.”
Although there is a growing body of literature on tDCS in migraine, few investigations have evaluated repeated tDCS stimulation treatments spanning 4 weeks or longer. For a study published in the Journal of Pain Research, Dr. Androulakis and colleagues performed a systematic review and meta-analysis to summarize and evaluate human studies assessing the efficacy of repetitive tDCS for at least 4 weeks in the setting of migraine. The qualitative meta-analysis included five randomized controlled trials, with a total of 104 patients with migraine.
Sustained Benefits Seen With Repetitive tDCSA significant reduction of migraine pain intensity was seen in patients treated with active tDCS when compared with those receiving sham tDCS, with a mean difference (MD) of −1.44 (Table). Within active tDCS treatment groups, pain intensity and duration were significantly improved from baseline after patients received tDCS (intensity MD, −1.86; duration MD, −4.42) and during a follow-up period (intensity MD, −1.52; duration MD, −1.94).
“Our study suggests that repetitive active tDCS stimulation for at least 4 weeks resulted in a significant reduction of migraine pain intensity when compared with sham stimulation,” says Dr. Androulakis. “In addition, both anodal and cathodal stimulation were shown to be effective for reducing pain intensity.”
The study team reported that their results persisted even with variations in tDCS parameters, including polarity, montage, and stimulation intensity between 1–2 mA. A trend was also seen in which the duration of migraine episodes was shorter with active tDCS stimulation. In addition, patients randomized to tDCS had fewer migraine attacks and a decrease in migraine days per month.
Research Needed to Confirm the Role of tDCS
“Although tDCS has yet to be approved by the FDA to treat any type of head pain disorder, it’s important to continue investigating this potential treatment option for migraine,” says Dr. Androulakis. According to the study, future research can help validate the findings by including larger sample sizes and matched group assignments. Clinical trials that test active tDCS while simultaneously measuring neuronal activity with EEG or functional MRI may lead to a better understanding of the underlying mechanism of action.
“More research into tDCS is warranted to determine if different montage configurations and stimulation intensity has an effect on the duration of migraine prevention,” Dr. Androulakis says. “It should be noted that most published studies on tDCS have focused only on pain as an outcome without evaluating pain-related disabilities. Future clinical trials should include assessments of migraine-related disability to fully understand the potential benefits of tDCS.” In addition, research is needed to determine if combining tDCS with other non-pharmacologic therapy for migraine results in synergistic long-term effects.