Stanford Team Maps Pain in the Brain First, Then Eases It in Two of Three Patients

Scientists have eased severe chronic pain in two volunteers by first mapping each person's pain signals in the brain and then targeting those exact spots with electricity. The work, a small series of case studies published July 30 in the journal Brain Stimulation, suggests that even tenacious pain signals can be interrupted if the right spot is found. Unlike the acute pain of a broken arm, chronic pain is generated by changes in the brain and spinal cord and lasts well beyond healing.

One existing approach is deep brain stimulation, or DBS, which uses electrodes on thin wires implanted in the brain and a battery pack implanted in the chest. DBS is most commonly used for Parkinson's disease and is being studied for other conditions including depression, but tests of DBS for chronic pain have produced inconsistent results, working for some people and not others.

That spottiness may reflect how pain is assembled. The experience is built by collections of brain networks handling sensory input, chemical signals and even emotional components, said Vivek Buch, a neurosurgeon and neuroscientist at Stanford University, and "somehow they're coming together as an integrated signal to give a person a perception of pain." Chronic pain, like depression and obsessive-compulsive disorder, is "just not one-size-fits-all," he said.

Buch and colleagues recruited three people with severe chronic face pain. Clinicians inserted temporary electrodes through small holes in the skull into key brain regions, and over the next three days sent small blips of electricity to different spots to see which ones changed each person's pain. One volunteer got little relief from any combination; two improved. A woman in her 40s then had four permanent electrode wires implanted in the regions that had responded, and was still feeling better at six and 12 months. The second woman plans a permanent implant soon.

Karl Deisseroth, a neuroscientist, psychiatrist and Howard Hughes Medical Institute investigator at Stanford, said identifying when a definitive treatment will not work matters as much as success. Neurosurgeon Michael Lim of Stanford University School of Medicine, who was not involved in the study, said clinicians have been limited in what they can do for these patients.