Current Concepts in back pain

Chronic Pain Linked to Atrophic Gray Matter Changes

By Merritt McKinney NEW YORK (Reuters Health) Mar 21 -

People with chronic back pain may experience atrophic changes in the gray matter of the brain, according to study findings presented Thursday at the annual meeting of the American Pain Society in Chicago. Still, the temporal nature of the relationship is unclear. But if chronic pain turns out to be a cause of gray matter atrophy, "the urgency to cure chronic pain becomes more important," according to Dr. A. Vania Apkarian at Northwestern University in Chicago, Illinois, principal investigator in the ongoing study. In previous research, Dr. Apkarian and his colleagues found that people with chronic pain may experience gray matter changes. In the new study, Dr. Apkarian's team continued to examine the brains of patients with chronic pain, in this case 10 people with chronic back pain. The gray matter of these patients was compared with that of 20 people without chronic pain. Compared with control subjects, chronic pain patients had less overall and thalamic gray matter. Not only was there less gray matter in terms of volume, but the tissue was also less dense, Dr. Apkarian said. "We have shown that brain chemistry is abnormal in chronic back pain patients," Dr. Apkarian said. He cautioned however, that "we have no idea" whether the shrinkage causes the back pain or is a result of it. In a future study, Dr. Apkarian said he would like to follow a group of people with chronic pain to see if the changes in gray matter progress. If gray matter continues to shrink as the pain continues, it would support the idea that the atrophy is caused by chronic pain, he said. One question Dr. Apkarian would like to see answered is whether treating the pain can reverse the damage to the brain's gray matter, although he said such a reversal is unlikely.