Disruption of Pleasure, Pain in Fibromyalgia Patients

A recent study shows that a disruption of brain signals for reward and punishment contributes to increased pain sensitivity, known as hyperalgesia, in fibromyalgia patients.

Background information from the study shows that fibromyalgia, known as a chronic musculoskeletal syndrome that's characterized by widespread joint and muscle pain along with other symptoms such as sleep disturbances, fatigue and cognitive difficulty, affects 3.4 percent of women and 0.5 percent of men in the United States, with an increasing number of cases with age.

"In patients with fibromyalgia there is an alteration in the central nervous system pain processing and a poor response to topical pain treatments, trigger point injections and opioids," lead author Dr. Marco Loggia from Massachusetts General Hospital and Harvard Medical School in Boston said, via a press release. "Our study examines the disruption of brain function involved in the individual experience of pain anticipation and pain relief."

For the study, researchers enrolled 31 patients with fibromyalgia and 14 healthy controls. Functionial magnetic resonance imaging (MRI) and cuff pressure pain stimuli was used on the leg of all subjects. During the MRI, participants also received visual cues alerting them of impending pain onset and pain offset.

Results found that during pain anticipation and relief, fibromyalgia patients exhibited less robust response within brain regions that involved sensory, affective, cognitive and pain regulating brain regions.

 "Our findings suggest that fibromyalgia patients exhibit altered brain responses to punishing and rewarding events, such as expectancy of pain and relief of pain," Loggia concludes, via the release. "These observations may contribute to explain the heightened sensitivity to pain, as well as the lack of effectiveness of pain medications such as opioids, observed in these patients. Future studies should further investigate the neurochemical basis underlying these dysfunctions."

More information regarding the study can be found via the journal Arthritis & Rheumatism.