What can we learn about selective attention processes in individuals with chronic pain using reaction time tasks? A systematic review and meta-analysis

Tactile acuity, left/right judgment performance, motor imagery ability, and pressure-pain threshold in patients with chronic rotator cuff-related shoulder pain: a cross-sectional case-control study

BACKGROUND

Chronic pain can alter cortical pain representation, and tests like Two-Point Discrimination Test (TPDT), Left/Right Judgment Task (LRJT), motor imagery, and Pressure-Pain Threshold (PPT) can assess these changes. However, their applicability to all pain mechanisms is uncertain.

OBJECTIVE

To compare the TPDT, LRJT, motor imagery ability, and PPT of chronic rotator cuff-related shoulder pain (C-RCRSP) patients with asymptomatic and pain-free controls.

METHODS

Forty-eight C-RCRSP patients and 45 pain-free controls were assessed using a caliper for TPDT and the Recognize® application for LRJT. Motor ability, PPT, physical function, fear avoidance, pain catastrophizing, and Central Sensitization Inventory (CSI) were also evaluated. As part of the subgroup analysis, C-RCRSP patients were divided into two groups based on their CSI (≥40, n = 19; <40, n = 29).

RESULTS

C-RCRSP patients demonstrated higher TPDT thresholds [acromion (F = 5.41, p = 0.001) and deltoid (F = 26.67, p < 0.001)] but no significant differences in LRJT performance [recognition accuracy (F = 2.47, p = 0.063) and response time (F = 0.98, p = 0.414)] than pain-free controls in both shoulder joints. C-RCRSP patients had poorer motor imagery abilities (p < 0.001). The deltoid region PPT differed significantly between the groups (F = 17.45, p < 0.001), but it was not significant for the tibialis anterior region (F = 1.16, p = 0.33). C-RCRSP patients with a CSI≥40 reported higher night pain, reduced shoulder range of motion, slower response times, poorer motor imagery ability, and higher scores on pain-related questionnaires compared to those with a CSI<40 (p = 0.043-<0.001).

CONCLUSION

C-RCRSP patients demonstrated poorer tactile acuity, mechanical sensitivity, and motor imagery ability especially in those with central sensitization, which should be considered in treatment planning.

Unconscious Activation of Negative Emotional Memories Increases Pain Unpleasantness

OBJECTIVE

The influence of unconscious emotional processes on pain remains poorly understood. The present study tested whether cues to forgotten unpleasant images might amplify pain (i.e., in the absence of conscious recall).

METHODS

Seventy-two healthy female adults (19 to 34 years) performed an adapted Think/No-think paradigm (T/NT) using 72 combinations of neutral face images (cues) paired with 36 neutral and 36 unpleasant images. After completion of the T/NT task, cues associated with forgotten neutral or unpleasant images were identified. Cues to either neutral or unpleasant images from the NT condition were then presented in randomized order while participants received intermediate-level thermal pain stimulation on the left hand. Ratings of both pain intensity and unpleasantness were acquired after each trial.

RESULTS

Mean pain unpleasantness ratings were greater during presentation of cues to forgotten negative versus neutral images (5.52 [SD = 2.06] versus 5.23 [SD = 2.10]; p = .02). This pattern was also present when comparing cues to remembered negative versus neutral images (5.62 [SD = 1.94] versus 5.04 [SD = 1.90]; p < .001). Mean pain intensity ratings were higher for cues to negative versus neutral images when remembered (5.48 [SD = 1.79] versus 5.00 [SD = 1.69]; p < .001), but not when forgotten (5.27 [SD = 1.96] versus 5.16 [SD = 1.93]; p = .30).

CONCLUSIONS

Using an adapted T/NT-Pain paradigm, this study demonstrated that cues to nonrecallable (but potentially unconsciously activated) negative emotional memories amplify pain unpleasantness, similar to known effects of conscious negative emotions.

The role of attention bias malleability in experiencing pain and associated disability

Background

Attentional processing of pain has been theorized to play a key role in the severity of pain and associated disability. In particular attentional bias towards pain information, resulting in poor pain outcomes, has been extensively researched. Recently, the idea was put forward that attention bias malleability (AM), i.e., the readiness to acquire an attentional bias irrespective of its direction, may be key in predicting poor pain outcomes. We tested this hypothesis in two studies.

Methods

In Study 1, 55 healthy participants completed an AM paradigm, followed by an experimental heat pain paradigm probing pain experience and pain-related task interference. In Study 2, 71 people with chronic pain completed an AM paradigm and questionnaires probing pain experience and associated disability.

Results

In Study 1, including healthy participants, no relationship was found between AM indices and experimental pain outcomes. In Study 2, including chronic pain patients, results indicated that higher levels of overall AM were related to higher levels of pain experience and disability.

Conclusion

This study partially supports the hypotheses that the degree to which individuals can adapt their attentional preference in line with changing environmental conditions is associated with poor pain outcomes. However, future research is needed to clarify inconsistent findings between healthy volunteers and chronic pain patients as well as to determine the causal status of AM in poor pain outcomes.

Investigating attention toward pain-related cues in an Arabic-speaking population with and without chronic pain

There is some evidence for attentional biases in individuals with chronic pain (CP). Cultural and linguistic differences might affect the manifestation of these processes across populations. However, such attentional biases have not been explored in the Arabic-speaking population. The current study investigated these attentional biases and possible associations with resilience. Two matched groups of Arabic-speaking participants with (58) and without (58) CP were recruited from Jordan and the United Kingdom. They completed emotionally modified versions of the Posner cueing and Stroop tasks, alongside questionnaires. Significant group differences were found for the Posner task, with the CP group exhibiting disengagement revealed by the inhibition of return (IOR) effect for sensory pain-related cues compared to delayed disengagement for the other cue types. The control group showed IOR across cue types. No group differences were found on the Stroop task. The CP group had lower resilience scores than healthy controls, and resilience moderated performance on the Posner task. The study provides preliminary evidence about the attentional processes in the Arabic population; the speed of disengagement is affected in the CP group with early disengagement for sensory pain-related information compared to affect pain and neutral stimuli. Furthermore, resilience levels in the CP and control group moderated the performance on the Posner task, suggesting that it influences attentional allocation. This study can help in understanding how the phenomenon of attention bias intertwines with the cultural and linguistic factors. Future research should further explore attentional dynamics across different time points in this population and the modulatory effect of resilience.