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08-05-2012 | Internal medicine | Article

Brain stimulation technique relieves migraine pain without side effects


Free abstract

MedWire News: A form of brain stimulation technology could help relieve the pain caused by chronic migraine without leading to adverse side effects, researchers say in Headache.

Although existing brain stimulation technologies can help relieve a migraine that is already underway, individuals who experience chronic migraine undergo 15 or more attacks a month "making treatment a constant battle" said study researcher Marom Bikson (City University of New York, USA) in a press statement.

In addition, these existing technologies have the disadvantages of involving "heavy, unwieldy equipment" and adverse side effects including seizures.

The randomized, placebo-controlled trial involved 13 patients aged 18-60 years who had been diagnosed with chronic migraine. All patients had an established headache history occurring on 15 or more days per month over the course of at least 1 year.

They were randomly assigned to either the sham (n=5) or active tDCS group (n=8) and received a total of 10 sessions over a 4-week period.

During each session, the anode electrode was placed over the motor cortex contralateral to the most painful side or the side where the symptoms typically begin, and the cathode electrode was placed over the contralateral supraorbital area.

In patients who underwent active tDCS, 2 mA of tDCS was applied for 20 minutes. For those who underwent sham tDCS, current was applied for only 30 seconds.

There was no significant difference in the frequency of adverse effects reported by the sham and active tDCS groups.

Mixed analysis of variance (ANOVA) showed a significant interaction effect between time and condition for daily pain perception (measured by visual analog scale [VAS]) and length of migraine episodes.

Post-hoc analysis revealed a significant decrease in pain levels at 4 months. In fact, pain levels continued to decrease significantly after the end of treatment; pain intensity according to the VAS declined from 4.6 at baseline to 2.9 at 120 hours after treatment.

A similar association was seen for length of migraine episodes, with the length of migraine attack decreasing from 8 hours at baseline to 0.9 hours at 120 hours after treatment.

The team's computational modeling studies predicted electric current flow in multiple cortical and subcortical regions associated with migraine pathophysiology. Indeed, significant electric fields were generated in the insula, ciongulate cortex, thalamus, and brainstem regions, as well as the targeted cortical regions.

The benefits of tDCS include its portability, commented Bikson. "You can walk around with it and keep it in your desk drawer or purse. This is definitely the first technology that operates on just a 9-volt battery and can be applied at home."

The team says the next step for their research is to scale up clinical trials to a larger study population, but emphasize that a market-ready version of tDCS is still years away.

"There's something about migraine pain that's particularly distressing," remarked Bikson. "If it's possible to help some people just get 30 percent better, that's a very meaningful improvement in quality of life."

By Piriya Mahendra

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