Cognitive Behavior Therapy May Ease Pain Response in Fibromyalgia

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Cognitive Behavior Therapy May Ease Pain Response in Fibromyalgia

NEW YORK (Reuters Health) Feb 10 - Fibromyalgia patients who received cognitive behavioral therapy in a pilot study had a higher threshold for the nociceptive-flexion reflex, an objective measure of the transmission of potentially painful stimuli to the central nervous system.

"The study supported my original hypothesis, that a psychological-based therapy has an effect on a biological marker of central sensitization - the latter playing a role in disease pathogenesis for fibromyalgia," said Dr. Dennis Ang of the Indiana University Division of Rheumatology, who led the study.

The randomized trial involved 32 women, 28 of whom completed the study. Patients with peripheral neuropathy, diabetes, demyelinating disorders, and inflammatory rheumatic diseases were not eligible. The study and its results were reported online January 29 in Arthritis Care and Research.

The cognitive therapy group received 6 weekly therapy sessions by phone. Dr. Ang and his colleagues measured the threshold of the nociceptive-flexion reflex in all participants at baseline, after 6 weeks and again after 12 weeks. The participants were allowed to continue taking their prescribed pain medications throughout the 12 weeks, but they did not take non-steroidal anti-inflammatory medications for 48 hours before testing, or as-needed pain medications for 6 hours before testing.

To test the nociceptive-flexion-reflex threshold, the team applied electrocutaneous stimulation to the sural nerve, increasing and decreasing the intensity to elicit a response. They expressed the threshold as the average of the levels of stimulation surrounding the second and third responses.

After 6 weeks, the nociceptive-flexion-reflex threshold, measured in milliamperes of electrocutaneous stimulation, increased by a mean of 4.4 mA in patients who had psychological therapy and decreased by a mean of 10.2 mA in controls (p = 0.005). The difference persisted at week 12 (7.3 mA vs. -5.4 mA, p = 0.01).

The groups reported similar reductions in pain ratings at week 6 (cognitive therapy: -20.2 vs. control: -14.9, p = 0.8) and week 12 (cognitive therapy: -8.9 vs. control: -10.8, p = 0.4). However, the authors report, "those receiving cognitive behavior therapy required more intense stimulation to elicit the nociceptive flexion response and rated that stimulation less painful than at baseline."

If the results are confirmed in larger studies, "Physicians will have an objective tool in the clinic that they can use to follow fibromyalgia patients," Dr. Ang said.

Arthritis Care Res 2010.

http://www.medscape.com/viewarticle/716854