Biomedicine

Zapping Migraines

Preliminary studies suggest that transcranial magnetic stimulation might help alleviate this common ailment.

Migraine sufferers may soon be able to shock their pain away. New research suggests that transcranial magnetic stimulation, a non-invasive technique to stimulate parts of the brain, can provide pain relief to migraine sufferers, if delivered soon after the onset of symptoms. And researchers are now testing a portable version of such a stimulator.

This experimental device, designed for home use, delivers two short pulses of electrical energy to the area of the brain where migraines are thought to originate. (Courtesy of Neuralieve.)

In transcranial magnetic stimulation, or TMS, an electromagnet is held against a patient’s head, emitting a magnetic field that creates an electrical current in the brain. Originally developed about two decades ago, new incarnations of the TMS technique are also being tested as a treatment for depression and other disorders.

Currently, drugs called triptans are the most common treatment for migraines. They target specific receptors in the brain, stopping pain and other migraine symptoms. Although triptans help many people, they’re ineffective in about one-third of cases, or approximately nine million Americans. “There’s a need for alternatives,” says Yousef Mohammad, M.D. and associate professor of neurology at Ohio State University, who ran the new trials.

At a meeting of the American Headache Society in Los Angeles this week, Mohammad presented data from two pilot studies testing TMS for migraine. In the first study, 42 patients reported to the hospital on first signs of migraine. About half were treated with a stationary device that delivered two pulses of magnetic energy, each lasting less than a millisecond, at about the strength of an MRI. The other half received placebo treatments, in which no pulses were delivered.

According to the findings, in the TMS group, patients reported that about 70 percent of their headaches were mild or no longer painful within two hours, compared with 48 percent in the placebo group. The TMS group also reported relief from other migraine symptoms, including nausea and sensitivity to light and noise, and no side effects. Mohammad says the results were encouraging, but cautions that, given the small number of patients in the study, it’s difficult to determine whether the numbers are statistically significant.

Mohammad’s team also tested a portable TMS device made by Neuralieve, a medical technology company in Sunnyvale, CA. Meant for home use, it allows patients to treat themselves by holding the device (which resembles a hairdryer) against their heads, and pressing a button that delivers the magnetic energy in two pulses with the same strength and duration as the nonportable version. In an uncontrolled study of 12 patients, the device was able to relieve or reduce 80 percent of patients’ headaches.

Again, Mohammad cautions that larger, controlled studies are needed to determine how effective the treatment will be for migraines. This is especially important because the placebo effect can be strong in clinical trials of pain treatments. Mohammad is planning such a study in collaboration with Neuralieve, which has developed an even smaller portable TMS that will be used in the trial. Mohammed and doctors from several other medical centers will have about 150 patients try out the device or a placebo at home. “That’s the main goal – for patients to use this at home,” Mohammad says. (He adds that he has no financial interest in the company.)

Andrew Hershey, professor of pediatrics and neurology and director of the Headache Center at Cincinnati Children’s Hospital Medical Center, says that treating migraines with TMS is “very interesting from a conceptual standpoint,” but adds that the recent study doesn’t indicate how widely applicable this technology might be.

The findings might also help scientists understand the source of migraines. Swelling blood vessels were once believed to cause migraines by stimulating nerves in the pain center of the brain. According to an alternative theory growing in acceptance, migraines may be partly the result of a wave of electrical activity spreading from the back to front of the brain, and finally activating nerves in the pain center. The electrical current created by TMS is thought to intercept the wave, pre-empting the pain.

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