There hasn't been a moment in the last 10 years in which Guinevere Janes' head didn't throb with migraine pain.

Before she was implanted with a St. Jude device that sends tiny pulses of energy to the occipital nerve at the base of her skull, her pain often measured a 10 on a scale of 1 to 10.

On Friday, she said her pain was a "3," thanks to the product she has had in her body since 2008 as part of a clinical trial here in the United States.

What does that reduction in pain mean for Janes, who is disabled by migraine? "It means that I am able to at least get up every day and read. It means that I can play with my niece and nephew," said the 38-year-old. "I am able to have a relationship with my family."

Increasingly, headache experts and med-tech companies such as Little Canada-based St. Jude are exploring the potential of peripheral nerve stimulation (PNS), using implantable medical devices to provide migraine relief to people for whom medication does not work. Clinical trials, such as the one in which Janes has been a participant, are showing promise.

"These are people who have headaches, more often than not, every day of their lives," said Dr. Stephen Silberstein, who founded and directs the Jefferson Headache Center at Thomas Jefferson University in Philadelphia and directs the trial in which Janes is enrolled. "We're taking the worst of the worst."

Last month, St. Jude Medical announced that it had received European approval for its Eon Mini neurostimulator, as well as its Eon and EonC neurostimulators, to treat intractable chronic migraine. The devices are like tiny pacemakers that send a programmable pulse to alleviate pain for people who have migraines at least 15 days a month. The devices still are awaiting approval by the U.S. Food and Drug Administration.

Before winning European approval, St. Jude conducted a large-scale study to evaluate PNS's impact on chronic migraine pain. After 12 weeks of stimulation, patients reported an average of six fewer headache days a month. After one year of stimulation, St. Jude reported that 65 percent of patients said they had excellent or good pain relief; 89 percent said they would recommend the procedure to someone else.

An estimated 36 million Americans suffer from migraines, according to the American Headache Society -- more than those who have asthma or diabetes combined. There is no cure for migraine, which is "characterized by pulsating or throbbing headache pain that can be moderate to severe in intensity," as well as other neurological symptoms.

Its severity can be disabling, painful enough to "cause work loss and absence from activities with family and friends," the society says, adding that migraine costs the United States more than $20 billion a year in direct medical costs and indirect expenses, such as missed workdays.

Most debilitating form

Intractable chronic migraine is considered even more debilitating. It is defined as a headache lasting at least four hours per day for 15 or more days per month, causing at least modest disability and not responding to three or more drugs.

The World Health Organization estimates that as many as 4 percent of adults have headaches 15 or more days per month. On a scale of 1 to 7, in terms of health impact and disability and 7 being the worst, the WHO ranks migraine as a 7.

Many treatments, including medications, alternative therapies and surgical options, are aimed at reducing migraine frequency or stopping the pain and associated symptoms after they've begun.

Doctors and med-tech companies have been studying and using pacemaker-like devices to treat pain and other afflictions -- everything from high blood pressure to incontinence to anxiety. So, Silberstein said, why not migraines?

The device is implanted just beneath the skin of the upper chest or near the hip. The Eon Mini is about the size of a man's wristwatch.

Tiny wires run just beneath the skin from the device to the occipital nerve -- considered one area affected by migraine.

"Put your hand at back of head, under the bone where it's soft," Silberstein said, describing the location of the occipital nerve. "How does it work? The pulse acts as a break on the pain signals ... turns the volume down."

Those with constant pain, he said, keep the device pulsating all the time.

Silberstein acknowledged that not all the patients enrolled in the trials were happy with the device. Some found the stimulation uncomfortable. Others had problems with the electrodes moving. For others, he said, it just doesn't work.

Worth continued study

Dr. Roger Cady, a headache specialist and official with the National Headache Foundation, said implanted medical devices probably can have a benefit for people with intractable migraine pain.

Migraine has long mystified doctors, he said. It used to be thought of as a blood vessel disease. Now it is considered a neurologic disease, affected by cranial and peripheral nerves in the brain.

"Suddenly, these types of devices may have some value," he said.

While medication helps many, Cady said, there are those who have come to have little hope for relief. For these sufferers, devices like the Eon may be an option.

"It definitely needs more study. We don't have clear answers," he said. "A lot of what is happening right now is learning how to do this best."

Cady, who has no connection to St. Jude or its study, said the work of Silberstein and St. Jude shows promise.

"Six more days [without headache] in the life of someone with this disease is huge," he said. "Lord knows we would like to do more, but this is a start."

Janes said she is hopeful that once the device is approved for sale in the United States, and Medicare agrees to pay for the implantation of more electrodes to other nerves, she may find enough relief to return to a more full life.

Once in a master's program at the University of Wisconsin, Janes, who now lives in suburban Philadelphia, said her pain became so severe and so constant that she had to leave school and quit working. There were days she couldn't even get out of bed. Now, with the decrease in pain, there is hope.

"I am incredibly lucky. I have family that supports me. I have some of the best doctors in the world," she said. "My story isn't done yet. I could someday be able to go and get a part-time job and become a member of society."

James Walsh • 612-673-7428