Stimulating Occipital Nerve Eases Cluster Headaches

But the pain returns once the experimental therapy is stopped, studies find

THURSDAY, March 8, 2007 (HealthDay News) -- Two pilot studies found that electrical stimulation of the occipital nerve helped ease the agony of cluster headaches, which some have likened to getting stuck in the eye with a hot poker.

The studies, which involved eight patients each, were published in this week's The Lancet and The Lancet Neurology.

"These studies concord to indicate that ONS (occipital nerve stimulation) is a clinically useful treatment in drug-resistant chronic cluster headache, and that it should receive a trial before hypothalamic deep brain stimulation which is also effective but not risk-less," said Dr. Jean Schoenen, author of the Lancet Neurology study and professor of neurology at Liege University in Liege, Belgium.

Previous trials of hypothalamic deep brain stimulation, which involves stimulating the hypothalamus region of the brain, showed a small risk of fatal hemorrhage.

Other experts urged caution when interpreting the new findings.

"You cannot generalize from two studies of eight people to the whole universe, but one would certainly call it very encouraging," said Dr. Jay Selman, a neurologist with Northern Westchester Hospital Center in Mount Kisco, N.Y., and clinical associate professor of neurology at Columbia University in New York City. "There were no significant side effects, no unintended consequences," Selman added.

Cluster headaches are much less common than migraines, affecting about one in 1,000 people. They typically strike in clusters once or twice a year, causing attacks one or two times a day for two to three months. The debilitating attacks last for about two hours and affect one side of the head.

"In the world of headaches, cluster headaches are much less common than tension-type headaches or migraines but are very severe and can be incredibly debilitating to patients," Selman explained. "Within the world of cluster headaches, there is a small group who have chronic cluster headaches, meaning they don't go more than about a month or so without attack. This subgroup is very difficult to manage. The problem is that they have ended up being on a variety of medications, often multiple medications, which don't tend to work well."

Some patients go so far as to have surgery, while other possibilities include pure oxygen and a nasal spray used to treat migraine headaches. That spray, called zolmitriptan (Zomig), appears to work by targeting nerves that carry pain signals.

Schoenen's study involved administering occipital nerve stimulation to eight patients with chronic cluster headaches. Two patients were free of the attacks after follow-ups of 16 and 22 months, and three patients had about a 90 percent reduction in attack frequency. One patient quit the trial after four months, because he felt the intervention wasn't beneficial. Overall, the rate of headache among the study participants decreased by 50 percent. The attacks came back when the stimulator was switched off.

The second study, conducted in Great Britain, also involved eight patients with cluster headaches for whom drug treatment hadn't worked. All were treated with electrodes implanted for occipital nerve stimulation.

After follow-ups lasting six to 27 months, six of the eight patients said the therapeutic benefit was great enough that they would recommend the procedure to others. Two patients noticed a "substantial" improvement (90 percent and 95 percent) in their attacks; three noticed a "moderate" improvement (40 percent, 60 percent and 20 percent to 80 percent, respectively); and one reported "mild" improvement (25 percent).

As in the Belgian study, symptoms returned almost immediately when the device malfunctioned -- for example, when the battery ran out.

"For people living with and suffering from intractable headache, developments are afoot," said Dr. Peter Goadsby, senior author of the British study and a professor at the Institute of Neurology at National Hospital for Neurology & Neurosurgery in London. "And for patients with intractable chronic cluster headache, a new era is beginning."

"Next, we need longer-term observation and further experience with the device, the development of better devices with longer battery lives and smaller technology," Goadsby said.

Schoenen agreed that more research into the treatments is needed, specifically research that "studies more patients and gets a more precise idea of the optimal stimulation parameters."

"We also need to perform studies to better understand how ONS works, she added. Currently, the mechanisms of action are poorly understood.

"The next step would be to undertake a larger study, probably in the range of 25 to 50 patients and, if possible, to follow them out longer," Selman added. "You would certainly think about going this route before subjecting somebody to surgery."

More information

Learn more about cluster headaches from the American Academy of Family Physicians.

SOURCES: Jean Schoenen, M.D., Ph.D., professor of neurology, Liege University, Liege, Belgium; Peter J. Goadsby, M.D., professor, Institute of Neurology, National Hospital for Neurology & Neurosurgery, London, England; Jay Selman, M.D., neurologist, Northern Westchester Hospital Center, Mount Kisco, N.Y., and clinical associate professor of neurology, Columbia University, New York City; March 8, 2007, The Lancet and The Lancet Neurology, online
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