Generalization and Extinction of Concept-BasedPain-Related Fear

Contingency Reversal in Conditioned Fear Learning: The Moderated Mediation Model of Intolerance of Uncertainty and Instruction

Objective

The study aimed to examine the roles of anxiety and intolerance of uncertainty (IU) in conditioned fear learning under an uncertain context induced by the contingency reversal of the association between the conditioned stimulus and the unconditioned stimulus (CS-US).

Methods

The study sample comprised 53 participants, randomly divided into two groups: a non-instruction group and an instruction group. The experimental procedure encompassed five stages: pre-acquisition, acquisition, generalization, reversal acquisition, and reversal generalization. Our study primarily focused on analyzing a moderated mediation model.

Results

In the instructed group, we observed that the reversed fear generalization response was directly influenced by the pre-reversal fear generalization response, while also being indirectly mediated by the IU factor. However, in the non-instructed group, we did not find a significant mediating effect of IU. Moreover, we noted that the mediation of IU was contingent on the instructional information. It is noteworthy that anxiety did not exhibit a discernible role in conditioned fear within the uncertainty condition in our study.

Conclusion

The findings provide novel insights into fear-related phenomena, emphasizing the intricate interplay between individual traits and fear generalization under conditions of uncertainty. They contribute to understanding the mechanisms of emotional and cognitive interactions in uncertain conditions.

High-Anxious People Generalize Costly Pain-Related Avoidance Behavior More to Novel Safe Contexts Compared to Low-Anxious People

Pain-related avoidance is adaptive when there is a bodily threat, but when it generalizes to safe movements/situations, it may become disabling. Both subclinical anxiety-a vulnerability marker for chronic pain-and chronic pain are associated with excessive fear generalization to safe stimuli/situations. Previous research focused mainly on passive fear correlates (psychophysiological arousal and self-reports) leaving avoidance behavior poorly understood. Therefore, we tested whether high-anxious individuals generalize their pain-related avoidance behavior more to novel, safe contexts than low-anxious people. In a robotic-arm-reaching task, both groups (low vs high trait anxiety) performed 1 of 3 movements to reach a target. In the threat context (black background), a painful stimulus could be partly/completely prevented by performing more effortful trajectories (longer and more force needed); in the safe context (white background), no pain occurred. Generalization of avoidance was tested in 2 novel contexts (light/dark gray backgrounds). We assessed pain expectancy, pain-related fear, startle eyeblink responses for all trajectories, and avoidance behavior (ie, maximal deviation from shortest trajectory). Results indicated that differential fear and expectancy selectively generalized to the novel context resembling the original threat context in both groups. Interestingly and in contrast with the verbal reports, high-anxious participants avoided more in the novel context resembling the original safe context, but not in the 1 resembling the threat context. No generalization emerged in the startle data. Because excessive pain-related avoidance specifically may cause withdrawal from daily life activities, these findings suggest that high-anxious individuals may be vulnerable to developing chronic pain disability. PERSPECTIVE: This paper shows that high-anxious people do not overgeneralize pain-related fear and pain expectancy learned in a threat context more to novel, safe contexts than low-anxious individuals, but that they do avoid more in those contexts. These findings suggest that high-anxious individuals may be vulnerable to developing chronic pain disability.

Influence of Family-Learned Fear-of-Pain on Patients

BACKGROUND

Fear-of-pain is a common feeling of patients and their family who experience or witness severe or chronic pain. Fear-of-pain may disturb patient's recovery, and also influence family support to assist patients' recovery.

AIM

This study is to measure the level of family support for each patient; evaluate the extent of the supporting families' fear-of-pain; and identify possible interventions in family support and family fear-of-pain.

METHODS

This cross-sectional descriptive research involved 77 participants in the orthopedics department of a tertiary hospital by convenience sampling. The online questionnaire includes general information, and scales of fear-of-pain, pain anxiety, pain vigilance and awareness, pain catastrophizing, and family support. T-test, Pearson correlation analysis and Spearman correlation analysis were used to analyze data.

RESULTS

Most participants reported that they experienced a moderate-to-high level of fear-of-pain, pain anxiety, pain vigilance and awareness. A total of 15.6% of participants are at risk of pain catastrophizing. The family's pain vigilance and awareness, and fear-of-pain were often similar to those of the patient, and their levels of pain anxiety and catastrophizing were often higher than the patient's. Family support and families' fear-of-pain affect patients' feelings of pain and families' behavior in decision-making for patient recovery, necessitating the development of interventions for patients' families.

CONCLUSIONS

Family members can develop the fear-of-pain from witnessing painful experiences and may exhibit fear-avoidance behaviors in deciding on patients' rehabilitation plan. Family support, including the type of relationship with families, and length of time family spent with the patient, had an effect on patients' pain and fear-of-pain.

Indoor or outdoor? Generalization of costly pain-related avoidance behavior to conceptually related contexts

When pain persists beyond healing time and becomes a "false alarm" of bodily threat, protective strategies, such as avoidance, are no longer adaptive. More specifically, generalization of avoidance based on conceptual knowledge may contribute to chronic pain disability. Using an operant robotic-arm avoidance paradigm, healthy participants (N=50), could perform more effortful movements in the threat context (e.g. pictures of outdoor scenes) to avoid painful stimuli, whereas no pain occured in the safe context (e.g. pictures of indoor scenes). Next, we investigated avoidance generalization to conceptually related contexts (i.e. novel outdoor/indoor scenes). As expected, participants avoided more when presented with novel contexts conceptually related to the threat context than in novel exemplars of the safe context. Yet, exemplars belonging to one category (outdoor/indoor scenes) were not interchangeable; there was a generalization decrement. Posthoc analyses revealed that contingency-aware participants (n=27), but not non-aware participants (n=23), showed the avoidance generalization effect and also generalized their differential pain-expectancy and pain-related fear more to novel background scenes conceptually related to the original threat context. In contrast, the fear-potentiated startle response was not modulated by context.

The clinical decision making process in the use of mobilisation with movement - A Delphi survey

BACKGROUND

Mobilisation with movement (MWM) is a method of treating musculoskeletal disorders. Although widely used clinically and with increasing research investigation, little is known about the decision making process for its utilization.

OBJECTIVES

To understand the factors experts believe important for utilization of MWM when assessing a patient, predicting responses to its delivery, responsive body areas, and expected outcomes to MWM.

DESIGN

A web-based Delphi study of experts in the use of MWM.

METHODS

Round one contained five open-ended questions regarding assessment strategies, prediction of successful and unsuccessful outcomes, body areas most responsive, and common outcome measures observed. Rounds 2 and 3 were quantitative and aimed at establishing consensus.

RESULTS

Thirty seven experts participated in the study and took part in round 1, thirty two in round 2, and twenty eight in round 3. The exclusion of red flags and impairment in range of motion (ROM), obtained the highest level of consensus for the item assessment strategies. Patient's presenting with a variety of issues on movement, in addition to mild to moderate levels of severity and immediately responsive to a trial MWM, were believed to respond favourably to MWM. Patients with predominant inflammatory pain, with high levels of psychosocial factors, increased central sensitization and not improving after a trial of MWM, were recognized as non-responders. Improvement of different aspects of movement (e.g. ROM, less fear) are the most common outcomes observed.

CONCLUSIONS

This study provides factors believed to be important in the decision making process when using MWM clinically.

Enhanced pain-related conditioning for face compared to hand pain

Pain is evolutionarily hardwired to signal potential danger and threat. It has been proposed that altered pain-related associative learning processes, i.e., emotional or fear conditioning, might contribute to the development and maintenance of chronic pain. Pain in or near the face plays a special role in pain perception and processing, especially with regard to increased pain-related fear and unpleasantness. However, differences in pain-related learning mechanisms between the face and other body parts have not yet been investigated. Here, we examined body-site specific differences in associative emotional conditioning using electrical stimuli applied to the face and the hand. Acquisition, extinction, and reinstatement of cue-pain associations were assessed in a 2-day emotional conditioning paradigm using a within-subject design. Data of 34 healthy subjects revealed higher fear of face pain as compared to hand pain. During acquisition, face pain (as compared to hand pain) led to a steeper increase in pain-related negative emotions in response to conditioned stimuli (CS) as assessed using valence ratings. While no significant differences between both conditions were observed during the extinction phase, a reinstatement effect for face but not for hand pain was revealed on the descriptive level and contingency awareness was higher for face pain compared to hand pain. Our results indicate a stronger propensity to acquire cue-pain-associations for face compared to hand pain, which might also be reinstated more easily. These differences in learning and resultant pain-related emotions might play an important role in the chronification and high prevalence of chronic facial pain and stress the evolutionary significance of pain in the head and face.

The relationship between fear generalization and pain modulation: an investigation in healthy participants

Background and aims

Pain-related fear and its subsequent generalization is key to the development and maintenance of chronic pain disability. Research has shown that pain-related fear acquired through classical conditioning generalizes following a gradient, that is, novel movements that are proprioceptively similar to the original pain-associated movement elicit more fear. Studies suggest that classical conditioning can also modulate pain and conditioned fear seems to mediate this effect. However, it remains uninvestigated whether this is also the case for generalized fear.

Methods

In a voluntary joystick movement paradigm, one movement (conditioned stimulus; CS+) was followed by pain (pain-US), and another was not (CS−). Generalization to five novel movements (generalization stimuli; GSs) with varying levels of similarity to the CSs was tested when paired with an at-pain-threshold intensity stimulus (threshold-USs). We collected self-reported fear and pain, as well as eyeblink startle responses as an additional index of conditioned fear.

Results

Results showed a fear generalization gradient in the ratings, but not in the startle measures. The data did not support the idea that fear generalization mediates spreading of pain.

Conclusions

Despite the lack of effects in the current study, this is a promising novel approach to investigate pain modulation in the context of chronic pain.

Implications

This study replicates the finding that pain-related fear spreads selectively towards movements that are proprioceptively more similar to the original pain-eliciting movement. Although results did not support the idea that such generalized fear mediates spreading of pain, the study provides a promising approach to investigate pain modulation by pain-associated movements.