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Brain scans of people with
fibromyalgia offer the first hard evidence of what patients already know:
Their pain is real and their threshold for tolerating it is substantially
lower than that of most individuals.
Fibromyalgia affects an estimated
2% to 4% of the population. Nine in
10 fibromyalgia patients are female. Patients commonly report
feeling tenderness, stiffness and sometimes unbearable pain in various
areas of the body. They also may suffer from fatigue, depression and gastrointestinal
problems. Some doctors without expertise in fibromyalgia have dismissed
patients' complaints because there have been no documented physical signs
of the disorder.
In the new report fibromyalgia
patients underwent a type of detailed brain scan known as functional magnetic
resonance imaging (fMRI) while an instrument intermittently applied different
levels of pressure to their left thumbnail.
When all study participants
received the same level of mild pressure, blood flow increased much more
in the brains of patients with fibromyalgia than among those in the control
group. The increased blood flow -- which is a "surrogate measure"
for nerve activity -- occurred in areas of the brain known to be associated
with pain.
In addition, when study participants
were subjected to different levels of pressure, fibromyalgia patients
reported pain at half the level of pressure that caused the same feelings
of pain among the healthy controls.
Something appears awry with
the way the central nervous system processes painful stimuli in fibromyalgia
patients.
Arthritis
& Rheumatism 2002;46:1333-1343
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