Imaging Shows Pleasure, Pain Brain Signals Disrupted in Fibromyalgia Patients

Earlier studies estimate that fibromyalgia affects 3.4% of women and 0.5% of men in the US Prevalence of this pain disorder increases with age, affecting more than 7% of women between 60 and 79 years of 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,” said lead author Dr. Marco Loggia from Massachusetts General Hospital (MGH; Boston, MA, USA) and Harvard Medical School (Boston, MA, USA). “Our study examines the disruption of brain function involved in the individual experience of pain anticipation and pain relief.”

For the present study, the research team enrolled 31 patients with fibromyalgia and 14 healthy controls. Functional magnetic resonance imaging (fMRI) scanning and cuff pressure-pain stimuli on the leg were performed on all study participants. During the fMRI scanning, participants received visual cues warning them of impending pain onset (pain anticipation) and pain offset (relief anticipation).

The study findings revealed that during pain anticipation and relief, fibromyalgia patients displayed less forceful response within brain regions involved in sensory, affective, cognitive and pain regulating processes. The ventral tegmental area (VTA) displayed activation during pain anticipation and stimulation, but deactivation during relief anticipation in healthy control subjects. By contrast, VTA responses during periods of pain, and anticipation of pain and relief, in fibromyalgia patients were substantially reduced or suppressed.

“Our findings suggest that fibromyalgia patients exhibit altered brain responses to punishing and rewarding events, such as expectancy of pain and relief of pain. 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,” Dr. Loggia concluded.

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