Emotional modulation of pain and spinal nociception in fibromyalgia

Abstract

Fibromyalgia (FM) is characterized by widespread pain, as well as affective disturbance (e.g., depression). Given that emotional processes are known to modulate pain, a disruption of emotion and emotional modulation of pain and nociception may contribute to FM. The present study used a well-validated affective picture-viewing paradigm to study emotional processing and emotional modulation of pain and spinal nociception. Participants were 18 individuals with FM, 18 individuals with rheumatoid arthritis (RA), and 19 healthy pain-free controls (HC). Mutilation, neutral, and erotic pictures were presented in four blocks; two blocks assessed only physiological-emotional reactions (i.e., pleasure/arousal ratings, corrugator EMG, startle modulation, skin conductance) in the absence of pain and two blocks assessed emotional reactivity and emotional modulation of pain and the nociceptive flexion reflex (NFR, a physiological measure of spinal nociception) evoked by suprathreshold electric stimulations over the sural nerve. In general, mutilation pictures elicited displeasure, corrugator activity, subjective arousal, and sympathetic activation, whereas erotic pictures elicited pleasure, subjective arousal, and sympathetic activation. However, FM was associated with deficits in appetitive activation (e.g., reduced pleasure/arousal to erotica). Moreover, emotional modulation of pain was observed in HC and RA, but not FM, even though all three groups evidenced modulation of NFR. Additionally, NFR thresholds were not lower in the FM group, indicating a lack of spinal sensitization. Together, these results suggest that FM is associated with a disruption of supraspinal processes associated with positive affect and emotional modulation of pain, but not brain-to-spinal cord circuitry that modulates spinal nociceptive processes.

Defensive reflexes in people with pain – a biomarker of the need to protect? A meta-analytical systematic review

“…Of the included studies, 12 reported reflex threshold (Boureau et al, 1991;Coffin et al, 2004;De Marinis et al, 2007;Sterling et al, 2008;Courtney et al, 2009Courtney et al, , 2010Lim et al, 2012;Neziri et al, 2012;Rhudy et al, 2013;Smith et al, 2013Smith et al, , 2014Curatolo et al, 2015), six reported reflex peak magnitude or AUC or both Avramidis et al, 1998;De Marinis et al, 2007;Peddireddy et al, 2009;Rhudy et al, 2013;Kofler and Halder, 2014), six reported reflex latency (Avramidis et al, 1998;Katsarava et al, 2004;De Marinis et al, 2007;Courtney et al, 2009;Peddireddy et al, 2009;Kofler and Halder, 2014), and two reported reflex duration (Courtney et al, 2009;Peddireddy et al, 2009). Pain populations included 'chronic pain', migraine, migraine without aura, tension type headache, chronic tension type headache, fibromyalgia, rheumatoid arthritis, chronic upper back pain, chronic low back pain, knee osteoarthritis, chronic whiplash associated disorder, irritable bowel syndrome, chronic lateral epicondylalgia ('tennis elbow'), and a combination of idiopathic pain, myofascial pain, and headache (see Table 1 for study details).…”

“…Twelve studies (Boureau et al, 1991;Coffin et al, 2004;De Marinis et al, 2007;Sterling et al, 2008;Courtney et al, 2009Courtney et al, , 2010Lim et al, 2012;Neziri et al, 2012;Rhudy et al, 2013;Smith et al, 2013Smith et al, , 2014Curatolo et al, 2015) (pooled n = 1906) were included in reflex threshold comparisons. Two studies investigated two patient groups (Rhudy et al, 2013;Smith et al, 2013), which increased our group comparisons to 15.…”

“…Two studies investigated two patient groups (Rhudy et al, 2013;Smith et al, 2013), which increased our group comparisons to 15. Pain groups had an overall lower reflex threshold than controls, with a large effect size [− 0.83 (95% CI, −1.18 to −0.47), p < 0.0001] (see Figure 2).…”

“…Six studies Avramidis et al, 1998;De Marinis et al, 2007;Peddireddy et al, 2009;Rhudy et al, 2013;Kofler and Halder, 2014) (pooled n = 297) were included in the main analysis for the size of the reflex. Two studies tested reflexes on two patient types (Avramidis et al, 1998;Rhudy et al, 2013), and one of these studies (Rhudy et al, 2013) tested two reflex types, increasing our group comparisons to 10.…”

“…Two studies tested reflexes on two patient types (Avramidis et al, 1998;Rhudy et al, 2013), and one of these studies (Rhudy et al, 2013) tested two reflex types, increasing our group comparisons to 10. There was no difference between pain and control groups for the size of the reflex [overall effect size, − 0.16 (95% CI, − 0.65 to 0.33), p = 0.52; see Figure 3], and there was a significant amount of heterogeneity between studies (I 2 = 72%, p < 0.001).…”