Patterns: Pain and the Downsized Brain By ERIC NAGOURNEY People with chronic back pain showed measurable shrinkage of their brains when they were given M.R.I. scans, researchers reported yesterday.
Writing in The Journal of Neuroscience, the researchers said that among the volunteers with back pain they had studied, the gray matter of the brain was 5 percent to 11 percent smaller than it was in other volunteers used for comparison. "The magnitude of this decrease is equivalent to the gray matter volume lost in 10 to 20 years of normal aging," they wrote.
The lead author of the study, Dr. A. Vania Apkarian, said he had done the research hoping that it would help explain earlier findings that people with chronic back pain experienced changes in brain chemistry that affected their performance on some kinds of tests of mental functioning. "Chronic pain patients, and specifically chronic back pain patients, seem to have impairment in emotional decision making," Dr. Apkarian said.
For this study, the researchers compared the brains of 26 volunteers who had been suffering from back pain for more than a year with those of 26 people without back pain. They found that the decrease in gray matter volume was directly linked to the length of time the patient had been in pain.
The findings have a number of implications. Researchers had assumed that the changes in brain chemistry seen earlier were temporary, and that they would go away if the pain did.
It now seems that if the back problems are untreated for too long, the changes become permanent and may even make it even harder to ease the pain. As for the behavioral effect, Dr. Apkarian said there was no evidence showing whether the changes measured in the laboratory spilled over into day-to-day life. "We obviously suspect it does," he said.
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