Chronic Pain Studies Examine Fibromyalgia

Media Contact:
Jennifer Park Lollar
(205)=20 934-3888
E-mail: jpark@uab.edu

Posted on June 7, 2005 at 2:51 p.m.

BIRMINGHAM, AL =97 Fibromyalgia, a disorder characterized = by=20 chronic muscle pain and unusually high pain sensitivity, is = the=20 focus of two ongoing studies funded by the National = Institutes of=20 Health at the University of Alabama at Birmingham (UAB).

One study is investigating the association between = emotional=20 stress and pain. =93We=92re interested in examining the = effects of=20 stress on pain experienced by people with fibromyalgia = compared to=20 healthy people,=94 said Laurence A. Bradley, Ph.D., = professor of=20 medicine with the Division of Immunology and Rheumatology at = UAB.

The first part of the study involves applying varying = levels of=20 heat to a small area on the wrist to produce perceptions = ranging=20 from warmth to mild or moderate pain. =93Before the heat = stimulus is=20 applied, participants are asked to vividly imagine either a = neutral=20 or stressful event from their life experience and then rate = both the=20 intensity and unpleasantness of the heat stimulus they = receive,=94=20 Bradley said.

Before and after each exercise, participants=92 = physiologic=20 responses to stress are assessed by measuring heart rate, = blood=20 pressure, and cortisol, a hormone that is released into the = blood in=20 response to stress. =93It usually takes about 30 minutes for = cortisol=20 levels to peak following a stressful event,=94 Bradley said. = =93So=20 one-hour rest periods follow each test. It takes about eight = hours=20 on a single day to complete all the exercises, although the=20 participants receive the heat stimuli only for brief periods = of=20 time.=94

The second part of the study, which takes about four = hours the=20 following day, entails neuroimaging. =93Using the same = procedures,=20 images are taken of the brain that vividly depict brain = blood flow=20 responses to the influences of stressful and non-stressful = events on=20 pain,=94 Bradley said.

The four-year study is scheduled to conclude this summer. = Researchers hope to gain a better understanding of factors = that=20 influence pain perception. =93There are many biological and = social=20 factors, like stress, that interact with one another to = alter pain=20 perception,=94 Bradley said. =93Understanding how these = factors interact=20 will help us better understand the pain experienced by = people with=20 fibromyalgia and may help us develop better, more targeted=20 treatments for these patients.=94

Another chronic pain study led by Bradley aims to = determine if=20 sisters of women with fibromyalgia, compared to the brothers = and=20 sisters of healthy women, exhibit greater sensitivity to = pain and if=20 so, if one or more genes are associated with this increased = risk.=20 =93This is the first study examining sex-related genetic = factors=20 associated with fibromyalgia,=94 Bradley said.

Earlier studies suggest women with fibromyalgia may have = a=20 genetically influenced impaired ability to inhibit pain. = There also=20 is evidence that the disorder occurs more frequently among = sisters,=20 compared with brothers, of patients with fibromyalgia. =93If = true,=20 this points to a sex-related, genetic predisposition to the=20 development of the disorder,=94 Bradley said.

The study is enrolling women with fibromyalgia, women = without=20 fibromyalgia, and the male and female siblings of both = groups of=20 women. =93We want to determine if siblings, especially = sisters, also=20 experience a greater sensitivity to pain,=94 Bradley said. = =93With=20 partners, we want to see if there any effects on pain = sensitivity=20 associated with sharing the same environment with someone = who has=20 fibromyalgia.=94

The study involves a series of brief tests to assess pain = sensitivity and a blood sample to measure levels of = serotonin, a=20 substance produced by the central nervous system involved in = reducing pain. =93In people with fibromyalgia, there is = evidence of an=20 abnormality in a particular gene that regulates the = production of=20 serotonin,=94 Bradley said. =93If this is confirmed, it = might help=20 explain why people with fibromyalgia have unusually low = levels of=20 serotonin.=94

Findings will provide researchers with a greater = understanding of=20 fibromyalgia and may help identify individuals at greater = risk for=20 unusually high pain sensitivity associated with the = disorder. =93It=20 also may provide valuable information about genetic factors = involved=20 in the development of fibromyalgia,=94 Bradley said.

For more information about these or other chronic pain = studies=20 under way at UAB, call (205)=20 934-9614.