“We’d need a large clinical trial to prove that these changes we see are driving the pain,” says Dr. Harris. Such a trial would require scanning a group of subjects lacking chronic pain, to see which ones nonetheless had neural signatures of fibromyalgia. They would then have to be followed for at least two, and maybe as much as 10 years to see if significant numbers developed the pain. Then, if the findings showed that the pathology predated the pain, it would be possible to say that the neuroimaging results were not a consequence of the pain, he says.
The alternative hypothesis—supported by “some in the field,” says Dr. Harris, is that some chronic pain conditions— possibly including fibromyalgia—have a “peripheral generator.” Osteoarthritis inflammation or nerve damage in stroke—to name two of multiple possibilities—could send pain signals into the brain, he says. Those who favor the peripheral generator posit that the persistence of peripheral pain information coming into the central nervous system could cause the increase in pain, says Dr. Harris.
Benefits of the Research
The most immediate benefit for patients is that the imaging demonstrates the oft-denied reality of their symptoms, “providing them with an objective finding, a data point that says they have a real condition, which implies they can be treated,” says Dr. Harris.
If the research is validated, it likely will also become possible to use fMRI to determine which patients will respond to pain medication. Pain medications work on only about 30% of pain patients, including roughly that fraction of fibromyalgia patients, says Dr. Harris. The pattern of activity in the brain—which brain regions are active or inactive at the same time—may be able to predict treatment response, he says. That would save money and time for both patients and doctors.
Other benefits may accrue to patients with pains that are generally assumed to be specific to a body part, such as osteoarthritis in a knee or pelvic pain in women, rather than generalized, as in fibromyalgia. The problem is that sometimes excising the peripheral body part, such as with knee replacement or hysterectomy, occasionally fails to cure the pain, potentially because the pain is generated in the brain. And physicians frequently don’t take a thorough history regarding pain symptoms. “Very rarely do they assess how widespread the pain is,” says Dr. Harris. “Do they have pain in other areas? Do they have these other types of disorders that co‑aggregate with fibromyalgia?”