New research shows that patients with fibromyalgia have hypersensitivity to non-painful events based on images of the patients’ brains, which show reduced activation in primary sensory regions and increased activation in sensory integration areas. Findings published in Arthritis & Rheumatology, a journal of the American College of Rheumatology (ACR), suggest that brain abnormalities in response to non-painful sensory stimulation may cause the increased unpleasantness that patients experience in response to daily visual, auditory and tactile stimulation.
Fibromyalgia is a chronic, musculoskeletal syndrome characterized by widespread pain, affecting roughly two percent of the world population, say experts. According to the ACR, five million people in the U.S. have fibromyalgia, which is more prevalent among women. In previous studies fibromyalgia patients report reduced tolerance to normal sensory (auditory, visual, olfactory, and tactile) stimulation in addition to greater sensitivity to pain.
For the present study, researchers used functional magnetic resonance imaging (fMRI) to assess brain response to sensory stimulation in 35 women with fibromyalgia and 25 healthy, age-matched controls. Patients had an average disease duration of 7 years and a mean age of 47.
According to the study, patients reported increased unpleasantness in response to multisensory stimulation in daily life activities. Furthermore, fMRI displayed reduced activation of both the primary and secondary visual and auditory areas of the brain, and increased activation in sensory integration regions. These brain abnormalities mediated the increased unpleasantness to visual, auditory and tactile stimulation that patients reported to experience in daily life.
Lead study author, Dr. Marina López-Solà from the Institute of Cognitive Science, University of Colorado Boulder said, “Our study provides new evidence that fibromyalgia patients display altered central processing in response to multisensory stimulation, which are linked to core fibromyalgia symptoms and may be part of the disease pathology. The finding of reduced cortical activation in the visual and auditory brain areas that were associated with patient pain complaints may offer novel targets for neurostimulation treatments in fibromyalgia patients.”
Altered fMRI responses to non-painful sensory stimulation in fibromyalgia patients
By Marina López-Solà, et al.
Objective: Fibromyalgia (FM) is a disorder characterized by chronic pain and enhanced responses to acute noxious events. However, the sensory systems affected in FM may extend beyond pain itself, as FM patients show reduced tolerance to non-nociceptive sensory stimulation. Characterizing the neural substrates of multisensory hypersensitivity in fibromyalgia may thus provide important clues about the underlying pathophysiology of the disorder. The aim of this study was to characterize brain responses to non-nociceptive sensory stimulation in FM patients and its relationship to subjective sensory sensitivity and clinical pain severity.
Methods: Functional magnetic resonance imaging (fMRI) was used to assess brain response to auditory, visual and tactile-motor stimulation in 35 women with FM and 25 matched controls. Correlation and mediation analyses were performed to establish the relationship between brain responses and three types of outcomes: subjective hyper-sensitivity to daily sensory stimulation, spontaneous pain, and functional disability.
Results: Patients reported increased subjective sensitivity (increased unpleasantness) in response to multisensory stimulation in daily life. FMRI revealed that patients showed reduced task-evoked activation in primary/secondary visual and auditory areas and augmented responses in the insula and anterior lingual gyrus. Reduced responses in visual and auditory areas were correlated with subjective sensory hyper-sensitivity and clinical severity measures.
Conclusion: FM patients showed strong attenuation of brain responses to non-painful events in early sensory cortices, accompanied by an amplified response at later stages of sensory integration in the insula. These abnormalities are associated with core fibromyalgia symptoms, suggesting that they may be part of the pathophysiology of the disease. © 2014 American College of Rheumatology.
Source: Arthritis & Rheumatology, September 15, 2014. By Marina López-Solà, Jesus Pujol, Tor D. Wager, Alba Garcia-Fontanals, Laura Blanco-Hinojo, Susana Garcia-Blanco, Violant Poca-Dias, Ben J. Harrison, Oren Contreras-Rodríguez, Jordi Monfort, Ferran Garcia-Fructuoso and Joan Deus. Department of Psychology and Neuroscience, Muenzinger D158, 345 UCB, Boulder, Colorado, 80309-0345. E-mail: email@example.com