Arterial spin labeling maps brain activity during low back pain

Aug 1 2011
Researchers at Brigham and Women's Hospital recently measured the brain activity of patients who were suffering from chronic low back pain. They monitored brain activity during flare-ups using arterial spin labeling, which measures blood flow to different portions of the brain.

Blood flow generally indicates the level of neuron activity in each portion of the brain. The scientists compared 32 patients, half with chronic low back pain and half without, and put each through three imaging sessions.

During the second and third sessions, pain was increased by clinical maneuvers or the application of heat, and results were recorded. Patients with chronic low back pain experienced increased brain activity when their discomfort grew worse, but not during the heat-induced pain.

"This study is a first step towards providing tools to objectively describe someone's chronic pain which is a subjective experience," said Dr. Ajay Wasan, the paper's lead author. "These changes occur in the network of areas in the brain that process pain and mood."

The observed brain activity was located in areas that previous study associated with pain as well as in some new areas. These findings may give insight into the similarities and differences between chronic and other forms of pain.

Researchers indicated that the study was only a beginning, but that they hoped that further investigation might eventually lead to better pain therapies tailored to specific patients.

Low back pain can have many causes, such as a pulled muscle or injury, a herniated disc or a disease such as osteoporosis, which weakens bones. The National Institute of Neurological Disorders and Stroke (NINDS) defines chronic low back pain as pain that lasts more than three months.

NINDS notes that low back pain symptoms are common, experienced by many people between the ages of 30 and 50, and may often result from aging, a sedentary lifestyle and a lack of exercise, rather than a serious condition.