How bad is that pain? Seems it’s only a matter of time until this work will provide the routine, objective measures that are needed to tell.
Researchers in the pain center at Harvard-affiliated Brigham and Women’s Hospital report they now can use a new imaging technique, “arterial spin labeling,” to measure worsening of a patient’s usual chronic low back pain (a problem for a majority of ME/CFS patients, and 63% of FM patients, according to “An Internet survey of 2,596 people with fibromyalgia,” by Robert M Bennett, et al.)
Arterial spin labeling detects increased blood flow in areas of the brain that are activated when patients with low back pain have a worsening of their usual chronic pain, according to the report, published online July 28 by the journal Anesthesiology [“Neural Correlates of Chronic Low Back Pain Measured by Arterial Spin Labeling”].
“This study is a first step towards providing tools to objectively describe someone’s chronic pain, which is a subjective experience,” says lead author Ajay Wasan, MD, MSc.
“We’ve found that when a patient has worsening of their usual pain, there are changes in the activity of the brain,” he says, and “These changes occur in the network of areas in the brain that process pain and mood.”
Researchers in the BWH Pain Management Center compared 16 patients with chronic low back pain (CLBP) to 16 healthy subjects. Participants underwent three imaging sessions.
• The first was for a characterization and training session.
• During the second session, researchers used clinical maneuvers, such as pelvic tilting or straight leg raising, to temporarily exacerbate back pain.
• In the third session, heat was applied to the skin at an intensity that matched the pain levels during the second session.
Patients rated their pain levels before and after the sessions and after each stimulation during the sessions.
During the last two sessions, designed to induce back pain and heat pain, respectively, researchers used the arterial spin labeling technique, which allows them to quantify the blood flow to specific regions of the brain over time. The amount of blood flow is indicative of neuron activity in that region of the brain.
They found that there was increased activity in the brain of chronic low back pain patients only when they experienced a worsening of their chronic pain and not during the heat pain session or in the healthy participants.
The researchers also note that some of the areas of the brain that were activated when participants experienced a worsening of chronic pain have been shown to be associated with other types of pain found in other studies.
However, the research team also observed activation of some areas, including the superior parietal lobule, which have been less frequently associated with pain in previous research.
“While this study begins to uncover some of the basic physiology of the brain as it processes pain, more studies are needed to help us understand how the brain function may change over the course of treatment of pain and to examine the brain mechanisms by which pain improves,” Dr. Wasan says.
“We are getting closer to describing, on an objective level, how the body and brain are reacting when a patient reports having more pain,” he adds. “We are hopeful that this could lead to an understanding of an individual patient’s neurocircuitry – and that knowledge could lead to therapies that would be tailored to the individual.”
Source: Brigham & Women’s Hospital news release, Jul 27, 2011