|
Posted: 10:37 AM Nov 4, 2006
Pain Research
Study in progress Fibromyalgia is a very common pain disorder for which there's no known cause or cure. Researchers are examining how emotions may color physical pain.
|
|
Fibromyalgia is a very common pain disorder for which there's no known cause or cure. Researchers are examining how emotions may color physical pain.
For 10 years, Sarah Wilson has lived with the daily muscle pain of fibromyalgia.
"Iif it’s um, really intense, it feels like a burning pain, burning, pulling, stretching," she says.
Sarah is in a study at the University of Alabama at Birmingham to test how emotional stress affects perceptions of pain.
Dr. Laurence Bradley, Ph. D., says, "None of us really think about what's the difference between the intensity of what I experience and the unpleasantness of what I experience. But in the laboratory we can ask people to differentiate between these two dimensions of pain."
Patients and healthy volunteers think about a stressful or non-stressful experience. Then, mild to moderate heat is applied to their arm. They rate what they feel and how they feel on a sliding scale.
Early results show both groups rate the pain the same, but people with fibromyalgia find it much more unpleasant.
The study also looks at physical responses.
Dr. Bradley says, "We can see changes in cerebral or brain blood flow that actually corresponds very nicely with the changes in patient's reports of the unpleasantness of their pain experience."
Understanding these changes could lead to better treatments.
The researchers are also studying depression as a potential risk factor for fibromyalgia and genetic factors that may play a role in pain sensitivity.
Fast Facts:
Fibromyalgia
Fibromyalgia is a condition that is characterized by serious, widespread chronic joint and muscle pain. The pain is often described as shooting, throbbing, aching, burning or twitching. The intensity of the pain varies and may be worse in the early morning, or after exposure to cold or humid weather, excessive activity and stress and anxiety.
The pain and tenderness associated with fibromyalgia is most severe at 18 specific areas of the body, called tender points. Those tender points are located in the area of the neck, elbows, hips and knees. Although there is no specific test for fibromyalgia, the condition is considered when other causes of the pain have been ruled out, pain persists for at least three months, and patients experience pain in at least 11 of the 18 tender points.
Fibromyalgia also causes several other symptoms. Patients can experience severe, debilitating fatigue, numbness or tingling in parts of the body, sensitivity to odors, bright lights or loud noises, sleep problems, headaches, digestive problems, impairment in memory and concentration, dry eyes, restless legs syndrome, dizziness, pelvic pain (in women), problems with coordination and depression.
According to the National Fibromyalgia Association, up to six percent of Americans have fibromyalgia. About 80 to 90 percent of patients are women. The condition can occur at any age, but is most commonly diagnosed between 20 and 50. The cause is unknown. However, patients with rheumatic diseases (like rheumatoid arthritis, lupus, and ankylosing spondylitis) appear to be at higher risk for the condition. Fibromyalgia also tends to run in families, but researchers are uncertain if genetics or environmental factors play a role in the increased risk.
The Role of Stress
Researchers at the University of Alabama at Birmingham recently conducted a study to determine the role of stress on pain perception in patients with fibromyalgia. Patients with the condition may respond differently to stress than healthy people.
Investigators recruited 120 patients with fibromyalgia and 60 healthy control patients. In the first part of the study, participants were asked to image a stressful or neutral event from their past. Then a heat stimulus was applied to the skin of the arm for a few minutes. Researchers measured heart rate, blood pressure and cortisol levels (a stress hormone) in the blood. Patients also rated the intensity and unpleasantness of the pain.
In the second part of the study, researchers repeated the same testing conditions with the heat stimulus. But this time, images of the brain were taken. The images allow investigators to study the differences in blood flow to the brain during periods of stressful and nonstressful pain.
Laurence Bradley, Ph.D., a Chronic Pain Researcher at the University of Alabama at Birmingham, says pain has both a sensory component and an emotional component. Sometimes our emotional response to pain has a great influence in how we perceive the pain. Preliminary results from the study show patients with fibromyalgia tend to rate the heat stimulus as much more unpleasant than healthy control subjects. Bradley says, if the results show that emotions play an important role in pain perception for those with fibromyalgia, doctors may want to consider treating depression in patients with higher levels of the emotional symptoms. That may help some fibromyalgia patients gain better control over their pain symptoms.
The researchers are now performing a second study to find out if brothers and sisters of patients with fibromyalgia also have a greater sensitivity to pain than brothers and sisters of healthy control subjects. The information may help doctors determine if genetic factors may be related to the development of fibromyalgia.
Web Resources
For information on fibromyalgia:
