Generalization Gradients in Cued and Contextual Pain-Related Fear: An Experimental Study in Healthy Participants

Abstract

Increasing evidence supports the notion that pain-related fear plays a key role in the transition from acute to chronic pain. Recent experimental data show that associative learning processes are involved in the acquisition of pain-related fear. An intriguing yet underinvestigated question entails how spreading of pain-related fear in chronic pain occurs. In a voluntary movement paradigm in which one arm movement (CS+) was followed by a painful stimulus and another was not (CS−) in the predictable group and painful stimuli were delivered during the intertrial interval (context alone) in the unpredictable group, we tested generalization of fear to six novel generalization movements (GSs) with varying levels of similarity between the original CS+ movement and CS− movement. Healthy participants (N = 58) were randomly assigned to the predictable or unpredictable group. Fear was measured via verbal ratings and eyeblink startle responses. Results indicated that cued pain-related fear spreads selectively to novel movements that are proprioceptively more similar to the CS+ than to those similar to the CS− in the predictable group, but not in the unpredictable group. This is the first study to demonstrate a generalization gradient of cued pain-related fear. However, this effect was only present in the startle eyeblink responses, but not in the verbal ratings. Taken together, this paradigm represents a novel tool to scrutinize the largely understudied phenomenon of the spreading of fear and avoidance in patients with chronic musculoskeletal pain and mapping possible pathological differences in generalization gradients and the spreading of pain in patients as compared with healthy controls.

Fear Generalization in Humans: Systematic Review and Implications for Anxiety Disorder Research

“…Subsequently, participants were required to make novel movements that were either proprioceptively related or unrelated to the original "painful" movement CS. It was found that fear significantly generalized over this proprioceptive dimension (see also, Meulders, Vandebroek, Vervliet, & Vlaeyen, 2013).…”

Lumbar range of motion in chronic low back pain is predicted by task‐specific, but not by general measures of pain‐related fear

“…The strength of this response follows a gradient which depends on how closely these stimuli match with each other (Vlaeyen, ). Although these concepts were initially based on research in anxiety disorders (Dymond, Dunsmoor, Vervliet, Roche, & Hermans, ), Meulders et al showed that in a predictable pain context, pain‐related fear also spreads to movements that are proprioceptively similar to the original painful movement, and that this generalization does indeed follow a gradient (Meulders, Vandebroek, Vervliet, & Vlaeyen, ; Meulders & Vlaeyen, ). Therefore, we hypothesized that the lumbar ROM during lifting would also, but less strongly, be predicted by the scores on pictures of the PHODA‐SeV that are proprioceptively related to a lifting manoeuver with a bent back.…”

Executive functions deficits impair extinction of generalization of fear of movement‐related pain

“…Replicating previous research, we observed that following successful differential fear acquisition, the strength of the fear response and pain expectancy to a novel unfamiliar movement was proportional to the resemblance of that movement with the original pain‐provoking movement (CS+) and the movement predicting the absence of pain (CS−). The more closely the novel movement resembled the original pain‐provoking movement, rather than the movement predicting the absence of pain, the greater the conditioned response (e.g., fear and pain expectancy) (Honig and Urcuioli, ; McLaren and Mackintosh, ; Lissek et al., ; Meulders et al., ; Geschwind et al., ). We extend previous knowledge in showing that low inhibitory capacity is associated with slower rates of extinction of generalized fear of movement‐related pain and pain expectancy.…”