Catastrophizing, Fibromyalgia, and the Cognitive Modulation of Pain
Study participants were exposed to painful stimuli either alone or during distracting cognitive tasks while undergoing functional magnetic resonance imaging.
Pain catastrophizing may be associated with a reduced ability to distract the mind from pain effectively in patients with fibromyalgia, resulting in potential exacerbation of chronic pain in those patients, according to study findings published in Pain Medicine.
Investigators enrolled 20 women with fibromyalgia and 18 healthy controls between the ages of 18 and 65 years. Study participants were exposed to painful stimuli either alone or during distracting cognitive tasks while undergoing functional magnetic resonance imaging. Catastrophizing was evaluated using the Pain Catastrophizing Scale (PCS).
The congruent and incongruent Stroop color-word tasks were used to distract patients from painful symptoms. For the congruent task, patients were shown a word describing a color, with the word's font representing that color (ie, the word “red” was in red font). An incongruent Stroop task included a word description of a color, with the word being a different font color from the described color (ie, the word “red” in a yellow font).
Patients with fibromyalgia reported greater pain during the painful stimuli compared with healthy controls (P =.019). Compared with pain stimuli delivered alone, pain delivered during the incongruent Stroop task was associated with lower pain intensity (P =.01) and unpleasantness (P =.02). Although healthy controls demonstrated lower pain intensity during this task (P =.02), they did not report any significant change in pain unpleasantness (P >.05). The congruent Stroop task was not associated with lower pain intensity or unpleasantness in patients with fibromyalgia.
In addition, for pain delivered during congruent and incongruent tasks, patients with fibromyalgia had moderate to large positive correlations between PCS scores and pain intensity and unpleasantness (rrange = 0.53-0.79; P <.05). There were no significant correlations between the tasks and PCS scores in healthy controls. During the Stroop tasks, patients who experienced catastrophizing had higher brain activity in the dorsolateral prefrontal cortex, which was positively associated with higher pain intensity (r =0.82) and unpleasantness (r =0.83) ratings.
Because of the study's limited sample size, the investigators were unable to determine whether patients with low or high levels of catastrophizing had distinct responses. In addition, the study cohort was restricted to women , precluding the ability to generalize these findings to the larger population of people with fibromyalgia.
“Catastrophizing may be disrupting the balance between facilitation and inhibition of pain processing and acting, in part, to maintain pain and associated symptoms,” concluded the study authors.
Ellingson LD, Stegner AJ, Schwabacher IJ, Lindheimer JB, Cook DB. Catastrophizing interferes with cognitive modulation of pain in women with fibromyalgia [published online February 21, 2018]. Pain Med. doi: 10.1093/pm/pny008