Chronic back pain, a condition afflicting millions, reduces the size of the brain by as much as 10 percent, a Northwestern University research study has found.
“Loss in brain density is related to pain duration,” said lead researcher A. Vania Apkarian, associate professor of physiology at Northwestern University Feinberg School of Medicine. The study, the first to examine brain changes in chronic pain conditions, was published in the Nov. 23, 2004 issue of The Journal of Neuroscience.
“About 1.3 cubic centimeters of brain tissue, the part that processes information and memory, are lost for every year of chronic pain,” continued the researcher at the Northwestern University Institute of Neuroscience.
Although chronic pain diminishes quality of life and increases anxiety and depression, it had previously been assumed that the brain reverts to its normal state after chronic pain stops. The new research suggests otherwise.
Apkarian and his fellow researchers used MRI data and two automated analysis techniques to contrast brain images from 26 participants with chronic back pain with those from matched normal subjects.
All participants with chronic back pain had continuous pain for more than a year, primarily localized to the lumbosacral region, including buttocks and thighs, with or without sciatic pain radiating down the leg.
In earlier research, the researchers found that back pain sustained for six months or longer is accompanied by abnormal brain chemistry. The changes in the brain seem localized in the area known to be important in making emotional evaluations, decision-making and social behavior. This preliminary finding motivated the researchers to study the potential link to brain atrophy.
Other researchers on the study were Yamaya Sosa, physiology; Sreepadma Sonty, neurology; Robert M. Levy, M.D., neurosurgery; R. Norman Harden, M.D., physical medicine and rehabilitation; Todd B. Parrish, radiology; and Darren R. Gitelman, M.D., neurology, radiology and the Cognitive Neurology an d Alzheimer’s Disease Center, at Feinberg.