Learning to predict pain: differences in people with persistent neck pain and pain-free controls

Abstract

Background Learning to predict threatening events enables an organism to engage in protective behavior and prevent harm. Failure to differentiate between cues that truly predict danger and those that do not, however, may lead to indiscriminate fear and avoidance behaviors, which in turn may contribute to disability in people with persistent pain. We aimed to test whether people with persistent neck pain exhibit contingency learning deficits in predicting pain relative to pain-free, gender-and age-matched controls. Method We developed a differential predictive learning task with a neck pain-relevant scenario. During the acquisition phase, images displaying two distinct neck positions were presented and participants were asked to predict whether these neck positions would lead to pain in a fictive patient with persistent neck pain (see fictive patient scenario details in Appendix A). After participants gave their pain-expectancy judgment in the hypothetical scenario, the verbal outcome (PAIN or NO PAIN) was shown on the screen. One image (CS+) was followed by the outcome “PAIN”, while another image (CS−) was followed by the outcome “NO PAIN”. During the generalization phase, novel but related images depicting neck positions along a continuum between the CS+ and CS− images (generalization stimuli; GSs) were introduced to assess the generalization of acquired predictive learning to the novel images; the GSs were always followed by the verbal outcome “NOTES UNREADABLE” to prevent extinction learning. Finally, an extinction phase was included in which all images were followed by “NO PAIN” assessing the persistence of pain-expectancy judgments following disconfirming information. Results Differential pain-expectancy learning was reduced in people with neck pain relative to controls, resulting from patients giving significantly lower pain-expectancy judgments for the CS+, and significantly higher pain-expectancy judgments for the CS−. People with neck pain also demonstrated flatter generalization gradients relative to controls. No differences in extinction were noted. Discussion The results support the hypothesis that people with persistent neck pain exhibit reduced differential pain-expectancy learning and flatter generalization gradients, reflecting deficits in predictive learning. Contrary to our hypothesis, no differences in extinction were found. These findings may be relevant to understanding behavioral aspects of chronic pain.

Impaired pain-related threat and safety learning in patients with chronic back pain

“…22,46 For instance, impaired differential fear and contingency learning has been found in several pain conditions, such as fibromyalgia, chronic hand pain, or chronic neck pain. 23,30,47,48 Of interest, these patient groups showed not only impaired threat learning but also reduced safety learning. Patients with irritable bowel syndrome, on the other hand, displayed enhanced safety learning compared with healthy volunteers.…”

“…A recent study found reduced differential learning in patients with persistent neck pain, with lower CS + and higher CS − pain expectancies compared with those in healthy individuals, but comparable extinction rates. 23 One reason for these inconsistent findings might be the sample sizes of these studies, which were rather small (ie, N = 30 or lower) for an investigation in a highly heterogeneous clinical population.…”

Movement-related pain as a learned response: an investigation of the possible mechanisms underlyng movement-related pain persistence and recovery in subjects with chronic musculoskeletal pain

“…Recently, one study demonstrated that conditioned pain expectancy was greater when sensory information about location of the body part in pain was less precise (286). There is also experimental data demonstrating that the specificity of fear responses appears to be affected by the somatotopic precision of the body part (287) and that people with chronic pain may present a less precise US-expectancy and fear learning than control subjects (239,288,289), which partially strengthens the second assumption of the IH.…”

“…increased arousal, vocalizations, flight or freezing, muscle startles) to contexts and sensory cues that preempt painful situations (25,142,240,241,244,245). However, as musculoskeletal pain is usually perceived during the execution of voluntary movements, individual with musculoskeletal pain may learn to fear and avoid movements perceived as harmful (144,239,(246)(247)(248)(249)(250)(251)(252)(253)(254).…”

You’ll never know if you never try

“…For example, generalization of fear to safe stimuli has been observed in several clinical populations such as people with panic disorder , generalized anxiety disorder (Lissek et al, 2014), and post-traumatic stress disorder (Lissek & Grillon, 2012). Similarly, whereas healthy participants were found to exhibit the expected fear generalization gradient, which decreases from the CS+ to CS-, people with fibromyalgia (Meulders, Meulders, et al, 2017a), chronic unilateral hand pain and chronic neck pain (Harvie et al, 2020), have been shown to exhibit flatter gradients with higher pain-expectancy towards GSs similar to the CS-. In another study, people with fibromyalgia showed less differential fear generalization between GSs similar to the CS+ and those similar to the CS-, in comparison to healthy control participants .…”