November 12, 2008 — Researchers have uncovered evidence that fibromyalgia is linked to brain-perfusion abnormalities that relate to the disability of the disease. Results from the molecular imaging study appear in the November issue of the Journal of Nuclear Medicine.
Fibromyalgia may be related to a global dysfunction of cerebral pain-processing.
"Fibromyalgia may be related to a global dysfunction of cerebral pain processing," lead investigator Eric Guedj, MD, from the Service Central de Biophysique et de MÃ©decine NuclÃ©aire, in Marseille, France, said 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 disorder," he noted.
The research team shows that brain abnormalities are independent of the patient's anxiety and depression status. Dr. Guedj told Medscape Neurology & Neurosurgery that he was not surprised by the findings and believes fibromyalgia is associated with a central substrate.
"Past imaging studies of patients with the syndrome, however, have shown above-normal cerebral blood flow in some areas of the brain and below-normal [blood flow] in other areas," Dr. Guedj noted.
In the current study, investigators looked at 20 women diagnosed with fibromyalgia and 10 healthy women. Subjects underwent single-photon-emission computed tomography (SPECT).
"After performing whole-brain scans on the participants," Dr. Guedj explained, "we used a statistical analysis to study the relationship between functional activity in even the smallest area of the brain and various parameters related to pain, disability, anxiety, and depression."
The researchers found that the Fibromyalgia Impact Questionnaire was positively correlated with bilateral parietal perfusion, including in the postcentral cortex.
Somatosensory Hyperperfusion Linked to Severity of Fibromyalgia
The researchers confirmed the presence of perfusion abnormalities in patients with fibromyalgia.
They showed that bilateral hyperperfusion of the parietal cortex and of the pre- and postcentral cortices are strongly correlated with the Fibromyalgia Impact Questionnaire score. Hypoperfusion of the left anterior temporal cortex was also strongly correlated in patients with disease.
This is reportedly the first time investigators have observed a relationship between somatosensory hyperperfusion and the clinical severity of fibromyalgia. "This reinforces the sensitization hypothesis," the researchers emphasize.
This reinforces the sensitization hypothesis.
"It's a first step," Dr. Guedj said during an interview. "We demonstrated significant abnormalities in comparison with healthy subjects. We now have to demonstrate that this functional pattern is specific to fibromyalgia in comparison with other painful diseases."
The researchers point to a number of limitations to their work. The study had a small sample and there was a large difference between the number of patients and the number of participants in the control group.
"The questionnaires chosen for our study are largely used in fibromyalgia," they write. "We should, however, discuss whether they are appropriate for such use. Also, the Tubingen Pain Behavior Scale was not evaluated by independent, masked investigators."
It has been suggested that the Fibromyalgia Impact Questionnaire is the most logical measure to evaluate functional status in clinical trials. Dr. Guedj and his team conclude that "these findings reinforce the concept of using brain-perfusion SPECT to objectively evaluate therapeutic results in controlled studies."
Bristol-Myers Squibb sponsored the color reproduction of the figures in the original paper. The researchers have disclosed no relevant financial relationships.
J Nucl Med. 2008;49:1798-1803. Abstract
Medscape Medical News © 2008 Medscape
Cite this: Allison Gandey. Fibromyalgia Associated With Functional Brain Abnormalities - Medscape - Nov 12, 2008.