Pain Images Show Rearranged White Matter in Brain

In examining the brains of people with a chronic pain condition known as complex region pain syndrome (CRPS), scientists at Northwestern University’s Feinberg School of Medicine found that patients’ brains “looked like an inept cable guy had changed the hookups, rewiring the areas related to emotion, pain perception and the temperature of their skin.”

In study results published in Neuron, scientists report they were able to link pain felt by patients with the white matter in their brains. The brains of 22 CRPS-affected people were compared to the brains of 22 normal subjects using an anatomical MRI and a diffusion tensor MRI. The images allowed scientists to see changes in the white matter in CRPS patients as well as “an atrophy of neurons or gray matter similar to what has been previously shown in other types of chronic pain patients.”

CRPS is a condition known to be caused by a major injury causing considerable damage to the hand or foot. While the pain for most people ceases once the injury has healed, in an estimated 5% of people the pain persists, sometimes for the remainder of the patient’s life. Symptoms of the condition include the pain spreading from the site of injury to the entire limb or body, skin color changes to blue or red, increased immune system activity with more blood immune markers, and skin temperature changes, becoming hotter at first and then colder as the condition becomes more chronic. An estimated 20,000 people in the US are believed to be affected by CRPS, though at times the medical community has expressed doubts as to whether the condition is real.

“This is the first evidence of brain abnormality in these patients,” said A. Vania Apkarian, PhD, lead investigator of the study. “People didn't believe these patients. This is the first proof that there is a biological underpinning for the condition. Scientists have been trying to understand this baffling condition for a long time.”

Apkarian also noted that people with CRPS have a high suicide rate. “Physicians don't know what to do. We don’t have the tools to take care of them.”

Researchers hope these new findings will aid the development of drugs to help CRPS patients. Further research will still be required to determine “if chronic pain causes these changes in the brain or if CRPS patients’ brains have pre-existing abnormalities that predispose them to this condition.”

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