Delayed effects of attention on pain sensitivity and conditioned pain modulation

Abstract

Background Efficacy of pain modulation is assessed as the difference in pain sensitivity during a painful conditioning, compared to before (conditioning pain modulation, CPM). Attention can be assessed with the Stroop task, in which participants report the number of words on a screen; either congruent or incongruent with the value of the words. Attention away from painful stimuli during CPM enhances the CPM effect. However, it is unknown if attention influences CPM effects when the two are done in sequence. Methods Healthy men (n = 25) underwent cuff algometry CPM‐assessment where the pressure‐pain detection and tolerance thresholds (PTT) were recorded on one leg with and without contralateral conditioning. Two identical sessions of four test stimuli equal to PTT (5 s, 1‐min interval, scored on a visual analogue scale, VAS) with a painful conditioning from the second to the last test‐stimulus were performed. Stroop sessions were followed by test stimuli with or without painful conditioning. Results The VAS scores in the first two sessions showed excellent reliability (ICC = 0.92). VAS scores were lower in sessions with Stroop compared to sessions without Stroop (p = .05) indicating an analgesic effect of Stroop. Participants were subgrouped into CPM responders and CPM non‐responders according to CPM effects in the first two sessions. CPM non‐responders (n = 13) showed facilitation to repeated noxious stimuli in all sessions with no effect of conditioning or Stroop (p = .02). Conclusion Attention and CPM both modulate pain in healthy men. Attention‐induced analgesia works in CPM non‐responders. Results indicate that attention and CPM are not the same and that they do not demonstrate additive effects when applied in sequence. Significance Pain sensitivity is reduced after an attention task in healthy men. The delayed effects from attention only have minor effects on Conditioned Pain Modulation (CPM), and results support that attention‐driven analgesia works independently of CPM. Results indicate that individual strategies for pain inhibition exist and that an overlap between the mechanisms of CPM and selective attention is limited. Moreover, painful phasic stimuli may increase the number of healthy volunteers with negative CPM effects.

The subsequent interruptive effects of pain on attention

“…The lack of the painful stimulus on Stroop task performance is likely due to the task's effect on individuals' pain perception (Seminowicz & Davis, 2007;Valet et al, 2004). For example, Hoegh et al (2019) found that the pain intensity scores of healthy individuals during Stroop task sessions with evoked pain were lower than those during sessions without the Stroop task, indicating an analgesic effect of the task due to distraction. RTs in the present study indicated that the Stroop task imposed a greater cognitive load than did the spatial cue task.…”

Comparison of five conditioned pain modulation paradigms and influencing personal factors in healthy adults

“…Attentional focus towards the conditioning stimulus had an additive effect on CPM‐magnitude with application of the CPT at the m. trapezius and CPA, which is in accordance with previous studies (Defrin et al., 2010; Ladouceur et al., 2012). It seems that attention driven analgesia uses partially overlapping mechanisms as those of pain‐driven analgesia (Hoegh et al., 2019) and this might explain the CPM‐effects for these paradigms. Although CPM‐efficacy is usually independent of perceived pain intensity (Nahman‐Averbuch et al., 2016), we found that perceived pain intensity of the conditioning stimulus influenced CPM‐efficacy for DIO at the m. trapezius.…”

Cognition and Pain: A Review

“…Young adults and middle-aged adults can use cognitively demanding tasks to diverge their attention and self-manage pain to some extent (Valet et al, 2004). Pain sensitivity is decreased with engagement in attention requiring tasks and with the use of environmental distractors (Sloan and Hollins, 2017;Hoegh et al, 2019). However, older adults are limited in this capacity, and chronic pain can impair independent living, a risk factor for physical disability, hospitalization, and death (van der Leeuw et al, 2018).…”