"Fibromyalgia may be related to a global dysfunction of cerebral pain-processing," study author Eric Guedj, MD, of Centre Hospitalo-Universitaire de la Timone, in Marseille, France, says in a news release. "This study demonstrates that these patients exhibit modifications of brain perfusion not found in healthy subjects and reinforces the idea that fibromyalgia is a 'real disease/disorder.'"
Fibromyalgia is a chronic disorder characterized by widespread muscle pain and fatigue. It affects 2%-4% of people, mostly women. It has been called the "invisible syndrome" because it can't be diagnosed based on a lab test or X-ray.
For this study, researchers took brain scans on 20 women with fibromyalgia and 10 women without the condition. Participants also answered questions to assess measures of pain, disability, anxiety, and depression.
The brain imaging technique, called single photon emission computed tomography (SPECT), is able to detect functional abnormalities in the brain.
Past imaging studies of patients with fibromyalgia had shown abnormalities in cerebral blood flow, also called brain perfusion. In some areas of the brain, blood flow was below normal, and in some areas, it was above normal. In this study, by using whole-brain scans on the participants, researchers were able to analyze how perfusion in each area of the brain related to measures of pain, disability, anxiety, and depression.
Researchers confirmed that patients with fibromyalgia exhibited brain perfusion abnormalities in comparison to the healthy participants. These abnormalities corresponded with the severity of the disease. An increase in blood flow was found in areas of the brain involved in sensing pain and a decrease was found within an area thought to be involved in emotional responses to pain.
There seemed to be no relationship between these abnormalities and presence of depression or anxiety. "We found that these functional abnormalities were independent of anxiety and depression status," Guedj says in a news release.