FINAL REPORT: Alternating Current Stimulation for the Acute Treatment of Migraine

Manuscript submitted to Neurology for publication.

Published in Journal of the Neurological Sciences, Volume 354, Issues 1-2, July 2015

Summary

In migraine treatment, although a broad range of pharmaceutical options exists, there is an increasing interest in non-pharmaceutical acute and prophylactic alternatives with lower side-effects and improved effectiveness than common medication. Transcranial electrical stimulation is one of these possibilities. The effect of the stimulation is probably based on the influence on cortical neuronal activity and therefore, with cortical spreading depression, thought to be the basis of the aura at the beginning of a migraine attack. In the present study, 46% of the treated patients had no pain 2 hours post-stimulation when inhibitory electrical stimulation over the primary visual cortex at the beginning of the attacks was applied. The placebo effect was high, reaching 29%, consistent with previously published pain research data. Interestingly, a subgroup of patients diagnosed with menstrual migraine benefited from the stimulation more than other types of migraine patients. In this group, 70% of the treated patients had no attacks during/after stimulation in the active stimulation group and 20% in the placebo group.

Hypothesis vs. Findings

The original protocol failed to reach significance between real and placebo stimulation groups. Altogether 78 migraine attacks were treated. Out of 50 real stimulations, 23 were successful, showing that in these 46% patients had no pain 2 hours post-stimulation. From 28 placebo stimulations, 8 were effective (29%). Thus, although we believe that with more patients, significance could be reached, we would instead suggest that the protocol be improved, since we now are quite confident that the used intensity was probably too low. We found that due to higher bone thickness about 3-4 times more stimulation intensity is needed at the visual cortex to reach similar effects that can be seen in the motor cortex.

Unanswered Questions

In migraine treatment, the effectiveness of acute and preventive pharmacological therapies is still limited: the drug side-effects are frequently worrisome and the frequency of headache and the intensity of pain are not significantly diminished. Therefore, the need for non-pharmacological alternatives is high. Transcranial stimulation might be one of these methods. But, the stimulation parameters, including the intensity, frequency and duration of the stimulation, should be investigated and optimized. We also learned that different types of migraine patients should probably be treated by different protocols. More work needs to be done to determine which protocols are most effective for different types of patients.

What This Research Means to You

The funding provided by the Migraine Research Foundation helped us to demonstrate that inhibitory electrical stimulation applied over the visual areas has positive effects with regard to the frequency and duration of migraine. Our data suggest that this kind of treatment might be a promising tool as an alternative or additional treatment option in migraine, although more challenging and time consuming compared to drug intake.