The Interruptive Effect of Pain in a Multitask Environment: An Experimental Investigation

The effect of experimental emotion induction on experimental pain: a systematic review and meta-analysis

ABSTRACT

The idea that emotions can influence pain is generally recognized. However, a synthesis of the numerous individual experimental studies on this subject is lacking. The aim of the present systematic review and meta-analysis was to synthesize the existing evidence on the effect of experimental emotion induction on experimental pain in nonclinical adults. PsycInfo and PubMed were searched up until April 10, 2023, for studies assessing differences in self-reported pain between emotion induction groups and/or control groups or between conditions within group. Risk of bias was assessed for the individual studies. The literature search yielded 78 relevant records of 71 independent studies. When compared with control conditions, the pooled results revealed a statistically significant pain-attenuating effect of positive emotion induction (between-group: Hedges g = -0.48, 95% CI: -0.72; -0.25, K = 9; within-group: g = -0.24, 95% CI: -0.32; -0.15, K = 40), and a statistically significant pain-exacerbating effect of negative emotion induction in within-group analyses but not between-group analyses (between-group: g = -0.29, 95% CI: -0.66; 0.07, K = 10; within-group: g = 0.14, 95% CI: 0.06; 0.23, K = 39). Bayesian meta-analysis provided strong support for an effect of positive emotion induction but weak support for an effect of negative emotion induction. Taken together, the findings indicate a pain-attenuating effect of positive emotion induction, while the findings for negative emotion induction are less clear. The findings are discussed with reference to theoretical work emphasizing the role of motivational systems and distraction for pain. Limitations include considerable heterogeneity across studies limiting the generalizability of the findings.

The Influence of Children's Pain-Related Attention Shifting Ability and Pain Catastrophizing Upon Negatively Biased Pain Memories in Healthy School Children

The current study investigated the influence of children's ability to flexibly shift attention toward and away from pain information on the development of negatively biased pain memories, thereby employing a direct measure of attention control reliant on behavioral responses in the context of pain (ie, an attention switching task). The direct influence of children's attention-shifting ability and pain catastrophizing as well as the moderating role of this shifting ability in the relationship between pain catastrophizing and the development of negatively biased pain memories was examined. Healthy school children (N = 41; 9-15 years old) received painful heat stimuli and completed measures of state and trait pain catastrophizing. They then performed an attention-switching task wherein they had to shift attention between personally relevant pain-related and neutral cues. Two weeks after the painful task, children's pain-related memories were elicited via telephone. Findings indicated that children's reduced ability to disengage attention away from pain information predicted more fear memory bias 2 weeks later. Children's pain-related attention-shifting ability did not moderate the relationship between children's pain catastrophizing and negatively biased pain memories. Findings highlight the contribution of children's attention control skills in the development of negatively biased pain memories. PERSPECTIVE: Results of the current study indicate that children with a reduced ability to shift attention away from pain information are at risk for developing negatively biased pain memories. Findings can inform interventions to minimize the development of these maladaptive negatively biased pain memories by targeting pain-relevant attention control skills in children.

Development and Evaluation of Linguistic Stimuli for Pain Research

Linguistic stimuli are commonly used in research to investigate the processing of pain. To provide researchers with a dataset of pain-related and non-pain-related linguistic stimuli, this research investigated 1) the associative strength between pain-related words and the pain construct; 2) the pain-relatedness ratings of pain words; and 3) the variability in the relatedness of pain words within pain word classifications (eg, sensory pain words). In Study 1, 194 pain-related and matched non-pain-related words were retrieved by reviewing the pain-related attentional bias literature. In Study 2, adults with (n = 85) and without (n = 48) self-reported chronic pain completed a speeded word categorization paradigm and rated the pain-relatedness of a subset of pain words. Analyses revealed that 1) despite differences in associative strength of 11.3% of the words between chronic and non-chronic pain groups, no overall group difference was found, 2) the chronic pain group rated the pain words as more pain-related compared to the non-chronic pain group, and 3) there was variability in the relatedness of pain words within pain word classifications. The findings highlight the importance of validating linguistic pain stimuli. The resulting dataset is openly accessible and new published sets can be added to the Linguistic Materials for Pain (LMaP) Repository. PERSPECTIVE: This article presents the development and preliminary evaluation of a large pool of pain-related and non-pain-related words in adults with and without self-reported chronic pain. Findings are discussed and guidelines are offered to select the most suitable stimuli for future research.

Linking Pain and Motor Control: Conceptualization of Movement Deficits in Patients With Painful Conditions

When people experience or expect pain, they move differently. Pain-altered movement strategies, collectively described here as pain-related movement dysfunction (PRMD), may persist well after pain resolves and, ultimately, may result in altered kinematics and kinetics, future reinjury, and disability. Although PRMD may manifest as abnormal movements that are often evident in clinical assessment, the underlying mechanisms are complex, engaging sensory-perceptual, cognitive, psychological, and motor processes. Motor control theories provide a conceptual framework to determine, assess, and target processes that contribute to normal and abnormal movement and thus are important for physical therapy and rehabilitation practice. Contemporary understanding of motor control has evolved from reflex-based understanding to a more complex task-dependent interaction between cognitive and motor systems, each with distinct neuroanatomic substrates. Though experts have recognized the importance of motor control in the management of painful conditions, there is no comprehensive framework that explicates the processes engaged in the control of goal-directed actions, particularly in the presence of pain. This Perspective outlines sensory-perceptual, cognitive, psychological, and motor processes in the contemporary model of motor control, describing the neural substrates underlying each process and highlighting how pain and anticipation of pain influence motor control processes and consequently contribute to PRMD. Finally, potential lines of future inquiry-grounded in the contemporary model of motor control-are outlined to advance understanding and improve the assessment and treatment of PRMD.

IMPACT

This Perspective proposes that approaching PRMD from a contemporary motor control perspective will uncover key mechanisms, identify treatment targets, inform assessments, and innovate treatments across sensory-perceptual, cognitive, and motor domains, all of which have the potential to improve movement and functional outcomes in patients with painful conditions.

The Effect of Electrical Stimulation-Induced Pain on Time Perception and Relationships to Pain-Related Emotional and Cognitive Factors: A Temporal Bisection Task and Questionnaire-Based Study

Pain has not only sensory, but also emotional and cognitive, components. Some studies have explored the effect of pain on time perception, but the results remain controversial. Whether individual pain-related emotional and cognitive factors play roles in this process should also be explored. In this study, we investigated the effect of electrical stimulation–induced pain on interval timing using a temporal bisection task. During each task session, subjects received one of five types of stimulation randomly: no stimulus and 100 and 300 ms of non-painful and painful stimulation. Pain-related emotional and cognitive factors were measured using a series of questionnaires. The proportion of “long” judgments of a 1,200-ms visual stimulus duration was significantly smaller with 300 ms painful stimulation than with no stimulus (P < 0.0001) and 100 ms (P < 0.0001) and 300 ms (P = 0.021) non-painful stimulation. The point of subjective equality (PSE) did not differ among sessions, but the average Weber fraction (WF) was higher for painful sessions than for no-stimulus session (P = 0.022). The pain fear score correlated positively with the PSE under 100 ms non-painful (P = 0.031) and painful (P = 0.002) and 300 ms painful (P = 0.006) stimulation. Pain catastrophizing and pain anxiety scores correlated significantly with the WF under no stimulus (P = 0.005) and 100 ms non-painful stimulation (P = 0.027), respectively. These results suggest that electrical stimulation–induced pain affects temporal sensitivity, and that pain-related emotional and cognitive factors are associated with the processing of time perception.

The subsequent interruptive effects of pain on attention

BACKGROUND

Pain is known to interrupt attentional performance selectively. In a previous study we showed that the interruptive effect of thermal pain on attention could persist up to 1500 ms after painful stimulus offset, but whether the pain modality affects this subsequent interruptive effect remains unclear.

METHODS

The present study was conducted to determine the time course of the interruptive effect of electrically induced pain on orienting and executive attention using various intervals between electric stimulation and attentional tasks (0, 250, 500, 750, 1000, 1250, and 1500 ms) and three study groups (pain, non-pain, and control). We performed two separate experiments in which participants performed a spatial cue task (experiment 1) and the Stroop task (experiment 2). Participants in the pain and non-pain groups received brief electric somatosensory stimulation, and those in the control group received no physical stimulus. We compared the performance of the three groups under the interstimulus interval (ISI) conditions.

RESULTS

The impairment of orienting attention prevailed under the first six ISI conditions in the pain and non-pain groups (F_{2, 63} = 5.72, P < 0.01); executive attention was not affected (F_1,66 = 1.64, P = 0.20), confirming the persistence of the interruptive effect after stimulus offset.

CONCLUSIONS

This study demonstrated the interruptive effect of somatic stimulation on subsequent orienting attention performance, with no effect on executive attention. These findings suggest that pain has differential effects on the components of attention, depending on its modality and salience.

Disruption of working memory and contralateral delay activity by nociceptive stimuli is modulated by task demands

ABSTRACT

Top-down processes allow the selection and prioritization of information by limiting attentional capture by distractors, and these mechanisms depend on task demands such as working memory (WM) load. However, bottom-up processes give salient stimuli a stronger neuronal representation and provoke attentional capture. The aim of this study was to examine the effect of salient nociceptive stimuli on WM while manipulating task demands. Twenty-one healthy participants performed a change detection task during which they had to determine whether 2 successive visual arrays were different or the same. Task demands were modulated by manipulating the WM load (set size included 2 or 4 objects to recall) and by the correspondence between the 2 successive visual arrays (change vs no change). Innocuous stimuli (control) or nociceptive stimuli (distractors) were delivered during the delay period between the 2 visual arrays. Contralateral delay activity and laser-evoked potentials were recorded to examine neural markers of visual WM and nociceptive processes. Nociceptive stimuli decreased WM performance depending on task demands (all P < 0.05). Moreover, compared with control stimuli, nociceptive stimuli abolished the increase in contralateral delay activity amplitude for set size 4 vs set size 2 (P = 0.04). Consistent with these results, laser-evoked potential amplitude was not decreased when task demands were high (P = 0.5). These findings indicate that WM may shield cognition from nociceptive stimuli, but nociceptive stimuli disrupt WM and alter task performance when cognitive resources become insufficient to process all task-relevant information.

Volitional Action Control and Depression in Chronic Pain: Does Action versus State Orientation Moderate the Relations of Pain-Related Cognitions to Depression?

In this study, we examined the conditional indirect and direct relations of pain-related cognitions to depression. Subjective helplessness was included as presumably mediating the relations of catastrophizing and thought suppression to depression due to motivational deficits. In addition, moderating effects of dispositional action versus state orientation were analyzed, whereby state orientation indicates volitional deficits in coping with distress. The study was based on self-report data from 536 patients with chronic non-specific low back pain at the beginning of inpatient rehabilitation. Moderated mediation analyses were performed. The indirect catastrophizing- and thought suppression-depression relations were (partially) mediated by subjective helplessness; and moderated by failure-related action versus state orientation. Moreover, action versus state orientation moderated the direct relation of thought suppression to depression. Results suggest that catastrophizing, thought suppression, and subjective helplessness do not lead to depression unless associated with self-regulatory inability (i.e., state orientation). In contrast, action-oriented patients more effectively self-regulate pain-related emotions, disengage from rumination, and distract from pain and thus better avoid the debilitating effects of negative pain-related cognitions on depression. Future research and treatment may more strongly focus on the role of motivational and volitional deficits underlying learned helplessness and depression in chronic pain.

Nociceptive stress interferes with neural processing of cognitive stimuli in Gulf War Veterans with chronic musculoskeletal pain

AIMS

Disrupted cognition and chronic musculoskeletal pain (CMP) are prevalent experiences among Gulf War Veterans (GWV). A negative association between CMP and cognition (i.e., chronic pain-related cognitive interference) has been observed in some chronic pain populations but has not been evaluated in GWV. Additional research suggests that disrupted cognition in GWV with CMP may be exacerbated by stressing the nociceptive system. Therefore, we compared cognitive performance and related neural activity between CMP and healthy control (CO) GWV in the absence and presence of experimental pain.

MAIN METHODS

During functional magnetic resonance imaging (fMRI), Veterans (CMP = 29; CO = 27) completed cognitive testing via congruent and incongruent conditions of a modified Stroop task (Stroop-only). A random subset (CMP = 13; CO = 13) also completed cognitive testing with experimental pain (Pain+Stroop). Yuen's modified t-test and robust mixed-model analysis of variance (ANOVA) models were used for analyzing cognitive performance data. Independent t-tests and repeated-measures ANOVA models were employed for fMRI data with thresholding for multiple-comparisons (p < 0.005) and cluster size (> 320 mm³).

KEY FINDINGS

Functional MRI analysis revealed significant between-group differences for the incongruent but not congruent-Stroop run. Neither correct responses nor reaction time differed between groups in either Stroop condition (all p ≥ 0.21). Significant group (CMP, CO) by run (Stroop-only, Pain+Stroop) interactions revealed greater neural responses in CMP Veterans during Pain+Stroop runs. No significant interactions were observed for correct responses or reaction time (p ≥ 0.31).

SIGNIFICANCE

GWV with CMP require a greater amount of neural resources to sustain cognitive performance during nociceptive stress.

Cognitive load and the effectiveness of distraction for acute pain in children

BACKGROUND

Distraction tasks that place continuous, high demand on executive resources have been shown to reduce pain intensity and pain unpleasantness ratings in some healthy adult samples. We examined the effects of a high-demand 'working memory' 1-back task compared to a low-demand 'motor control' task on pain intensity and unpleasantness ratings in healthy children. Additionally, dispositional mindfulness was examined to explore the mechanisms of distraction on the affective processing of pain.

METHODS

Fifty-seven children (9-13 years old) experienced three randomly presented heat levels (not painful, slightly painful, moderately painful) during two distraction conditions involving different levels of cognitive load (a high load 'working memory' task and a low load 'motor' control task) in counter-balanced order. Children completed measures of dispositional mindfulness, and attentional control and emotional control.

RESULTS

As predicted, children's pain intensity and pain unpleasantness ratings were lower in the high load condition compared to the low load condition. These differences were amplified in the moderately painful heat trials. In contrast with predictions, dispositional mindfulness did not significantly predict the effectiveness of distraction. Dispositional mindfulness was significantly related to measures of children's attentional and emotional control abilities; however, an exploratory serial mediation model did not produce significant indirect or overall effects to suggest a strong influence of mindfulness on the effectiveness of distraction.

CONCLUSIONS

Results demonstrate that distraction that places higher demand on executive resources is more effective for acute pain management for children. Further research is needed to explore cognitive and affective moderators of the effectiveness of distraction for children.

SIGNIFICANCE

This study is one of the first to demonstrate that working-memory engagement can attenuate pain intensity and pain unpleasantness in children aged 9-13. The findings suggest that distraction tasks used in clinical settings for moderately painful medical procedures may benefit more children if they are adequately demanding of cognitive resources.

Time Course of Attention Interruption After Transient Pain Stimulation

Although pain has been shown to affect attentional performance, little is known about the time course of attention interruption after pain stimulus perception. The present study examined the time course of the effects of transient heat pain stimulation on 2 components of attention. Three groups of subjects performed attention tasks under pain, warmth, and no-stimulation control conditions, respectively. The pain and warmth groups received brief physical stimulation. Attention tasks were presented 0 ms, 250 ms, 750 ms, or 1500 ms after the end of stimulation. The 2 attention tasks, namely the spatial cue task (Experiment 1, N = 92) and a Stroop task (Experiment 2, N = 86), were conducted separately. In Experiment 1, attentional orientation of the pain and warmth groups was significantly impaired for at least 1.5 seconds after the physical stimulation had ended. Interestingly, this effect lasted longer for the warmth group than for the pain group. In Experiment 2, pain stimulation had no effect on executive attention at any time. We concluded that attentional orientation is selectively disrupted by both pain and warmth stimuli, but recovers earlier from pain. PERSPECTIVE: This article is concerned with the subsequent interruptive effect of pain on attentional orientation and executive attention by using the spatial cue task and the Stroop task, respectively. These measures offer options for investigating the time course of attention interruption after transient pain stimulation.

Feeling Hurt: Revisiting the Relationship Between Social and Physical Pain

Pain overlap theory has generated decades of controversy and still receives considerable research attention. A major advance has been the revelation that social and physical pain activate similar neural regions, providing suggestive evidence of a “piggybacked” alarm system that coevolved to detect social exclusion. Recent developments, however, have brought neural evidence for pain overlap into question. We analyze these developments from a social psychological perspective and identify the need for a reformulated approach. To meet this need, we provide a framework that a priori predicts generalized overlap and specific divergence across a range of biopsychosocial domains. The framework points to a functional pattern for similarities and differences, which can be utilized to generate testable hypotheses so that the field can move forward. To demonstrate the utility and promise of the framework, we identify key hypotheses relating to attention, motivation, and responses to pain, and review research relevant to these hypotheses.

Activity interruptions by pain impair activity resumption, but not more than activity interruptions by other stimuli: an experimental investigation

Interrupting ongoing activities whilst intending to resume them later is a natural response to pain. Whereas this response facilitates pain management, at the same time it may also disrupt task performance. Previous research has shown that activity interruptions by pain impair subsequent resumption of the activity, but not more than pain-irrelevant interruptions. Ongoing task complexity and pain threat value might influence interruption effects. In this experiment, we adjusted a paradigm from outside the field of pain to investigate how activity interruptions by pain affect task performance. Healthy participants (n = 69) were required to answer a series of questions, in a specific sequence, about presented letter-digit combinations. This ongoing task was occasionally interrupted by painful electrocutaneous or nonpainful vibrotactile stimulation (between-subjects), followed by a typing task. On interruption completion, participants were required to resume the ongoing task at the next step of the question sequence. Results indicate impaired sequence accuracy (less frequent resumption at the correct step of the sequence) but preserved nonsequence accuracy (similarly frequent correct responses to question content) immediately after an interruption. Effects were not larger for interruptions by pain compared with nonpain. Furthermore, participants in the 2 conditions reported similar task experience, namely task motivation, perceived difficulty, and confidence to resume the interrupted task. Pain catastrophizing did not influence the results. As in previous studies, activity interruptions by pain were shown to impair the resumption of a task that requires keeping to a step sequence, but not more than interruptions by nonpainful stimuli. Potential explanations are discussed.

A break from pain! Interruption management in the context of pain

Activity interruptions, namely temporary suspensions of an ongoing task with the intention to resume it later, are common in pain. First, pain is a threat signal that urges us to interrupt ongoing activities in order to manage the pain and its cause. Second, activity interruptions are used in chronic pain management. However, activity interruptions by pain may carry costs for activity performance. These costs have recently started to be systematically investigated. We review the evidence on the consequences of activity interruptions by pain for the performance of the interrupted activity. Further, inspired by literature on interruptions from other research fields, we suggest ways to improve interruption management in the field of pain, and provide a future research agenda.

Filling the glass: Effects of a positive psychology intervention on executive task performance in chronic pain patients

BACKGROUND

Chronic pain is associated with emotional problems as well as difficulties in cognitive functioning. Prior experimental studies have shown that optimism, the tendency to expect that good things happen in the future, and positive emotions can counteract pain-induced task performance deficits in healthy participants. More specifically, induced optimism was found to buffer against the negative effects of experimental pain on executive functioning. This clinical experiment examined whether this beneficial effect can be extended to a chronic pain population.

METHODS

Patients (N = 122) were randomized to a positive psychology Internet-based intervention (PPI; n = 74) or a waiting list control condition (WLC; n = 48). The PPI consisted of positive psychology exercises that particularly target optimism, positive emotions and self-compassion.

RESULTS

Results demonstrated that patients in the PPI condition scored higher on happiness, optimism, positive future expectancies, positive affect, self-compassion and ability to live a desired life despite pain, and scored lower on pain catastrophizing, depression and anxiety compared to patients in the WLC condition. However, executive task performance did not improve following completion of the PPI, compared to the WLC condition.

CONCLUSIONS

Despite the lack of evidence that positive emotions and optimism can improve executive task performance in chronic pain patients, this study did convincingly demonstrate that it is possible to increase positive emotions and optimism in chronic pain patients with an online positive psychology intervention. It is imperative to further explore amendable psychological factors that may reduce the negative impact of pain on executive functioning.

SIGNIFICANCE

We demonstrated that an Internet-based positive psychology intervention strengthens optimism and positive emotions in chronic pain patients. These emotional improvements are not associated with improved executive task performance. As pain itself often cannot be relieved, it is imperative to have techniques to reduce the burden of living with chronic pain.

Taking a break in response to pain. An experimental investigation of the effects of interruptions by pain on subsequent activity resumption

BACKGROUND AND AIMS

Interrupting ongoing activities with the intention to resume them again later is a natural response to pain. However, such interruptions might have negative consequences for the subsequent resumption and performance of the interrupted activity. Activity interruptions by pain may be more impairing than interruptions by non-painful stimuli, and also be subjectively experienced as such. These effects might be more pronounced in people high in pain catastrophizing. These hypotheses were investigated in two experiments.

METHODS

In Experiment 1, healthy volunteers (n=24) performed an ongoing task requiring a sequence of joystick movements. Occasionally, they received either a painful electrocutaneous or a non-painful vibrotactile stimulus, followed by suspension of the ongoing task and temporary engagement in a different task (interruption task). After performing the interruption task for 30s, participants resumed the ongoing task. As the ongoing task of Experiment 1 was rather simple, Experiment 2 (n=30) included a modified, somewhat more complex version of the task, in order to examine the effects of activity interruptions by pain.

RESULTS

Participants made more errors and were slower to initiate movements (Experiment 1 & 2) and to complete movements (Experiment 2) when they resumed the ongoing task after an interruption, indicating that interruptions impaired subsequent performance. However, these impairments were not larger when the interruption was prompted by painful than by non-painful stimulation. Pain catastrophizing did not influence the results.

CONCLUSIONS

Results indicate that activity interruptions by pain have negative consequences for the performance of an activity upon its resumption, but not more so than interruptions by non-painful stimuli. Potential explanations and avenues for future research are discussed.

IMPLICATIONS

Interrupting ongoing activities is a common response to pain. In two experiments using a novel paradigm we showed that activity interruptions by pain impair subsequent activity resumption and performance. However, this effect seems to not be specific to pain.

How Accurate Appraisal of Behavioral Costs and Benefits Guides Adaptive Pain Coping

Coping with pain is a complex phenomenon encompassing a variety of behavioral responses and a large network of underlying neural circuits. Whether pain coping is adaptive or maladaptive depends on the type of pain (e.g., escapable or inescapable), personal factors (e.g., individual experiences with coping strategies in the past), and situational circumstances. Keeping these factors in mind, costs and benefits of different strategies have to be appraised and will guide behavioral decisions in the face of pain. In this review we present pain coping as an unconscious decision-making process during which accurately evaluated costs and benefits lead to adaptive pain coping behavior. We emphasize the importance of passive coping as an adaptive strategy when dealing with ongoing pain and thus go beyond the common view of passivity as a default state of helplessness. In combination with passive pain coping, we highlight the role of the reward system in reestablishing affective homeostasis and discuss existing evidence on a behavioral and neural level. We further present neural circuits involved in the decision-making process of pain coping when circumstances are ambiguous and, therefore, costs and benefits are difficult to anticipate. Finally, we address the wider implications of this topic by discussing its relevance for chronic pain patients.

The effects of experimental pain and induced optimism on working memory task performance

Background/aims

Pain can interrupt and deteriorate executive task performance. We have previously shown that experimentally induced optimism can diminish the deteriorating effect of cold pressor pain on a subsequent working memory task (i.e., operation span task). In two successive experiments we sought further evidence for the protective role of optimism on pain-induced working memory impairments. We used another working memory task (i.e., 2-back task) that was performed either after or during pain induction.

Methods

Study 1 employed a 2 (optimism vs. no-optimism) × 2 (pain vs. no-pain) × 2 (pre-score vs. postscore) mixed factorial design. In half of the participants optimism was induced by the Best Possible Self (BPS) manipulation, which required them to write and visualize about a life in the future where everything turned out for the best. In the control condition, participants wrote and visualized a typical day in their life (TD). Next, participants completed either the cold pressor task (CPT) or a warm water control task (WWCT). Before (baseline) and after the CPT or WWCT participants working memory performance was measured with the 2-back task. The 2-back task measures the ability to monitor and update working memory representation by asking participants to indicate whether the current stimulus corresponds to the stimulus that was presented 2 stimuli ago. Study 2 had a 2 (optimism vs. no-optimism) × 2 (pain vs. no-pain) mixed factorial design. After receiving the BPS or control manipulation, participants completed the 2-back task twice: once with painful heat stimulation, and once without any stimulation (counterbalanced order). Continuous heat stimulation was used with temperatures oscillating around 1 °C above and 1 °C below the individual pain threshold.

Results

In study 1, the results did not show an effect of cold pressor pain on subsequent 2-back task performance. Results of study 2 indicated that heat pain impaired concurrent 2-back task performance. However, no evidence was found that optimism protected against this pain-induced performance deterioration.

Conclusions

Experimentally induced pain impairs concurrent but not subsequent working memory task performance. Manipulated optimism did not counteract pain-induced deterioration of 2-back performance.

Implications

It is important to explore factors that may diminish the negative impact of pain on the ability to function in daily life, as pain itself often cannot be remediated. We are planning to conduct future studies that should shed further light on the conditions, contexts and executive operations for which optimism can act as a protective factor.

The Experience of Cognitive Intrusion of Pain: scale development and validation

Patients with chronic pain often report their cognition to be impaired by pain, and this observation has been supported by numerous studies measuring the effects of pain on cognitive task performance. Furthermore, cognitive intrusion by pain has been identified as one of 3 components of pain anxiety, alongside general distress and fear of pain. Although cognitive intrusion is a critical characteristic of pain, no specific measure designed to capture its effects exists. In 3 studies, we describe the initial development and validation of a new measure of pain interruption: the Experience of Cognitive Intrusion of Pain (ECIP) scale. In study 1, the ECIP scale was administered to a general population sample to assess its structure and construct validity. In study 2, the factor structure of the ECIP scale was confirmed in a large general population sample experiencing no pain, acute pain, or chronic pain. In study 3, we examined the predictive value of the ECIP scale in pain-related disability in fibromyalgia patients. The ECIP scale scores followed a normal distribution with good variance in a general population sample. The scale had high internal reliability and a clear 1-component structure. It differentiated between chronic pain and control groups, and it was a significant predictor of pain-related disability over and above pain intensity. Repairing attentional interruption from pain may become a novel target for pain management interventions, both pharmacologic and nonpharmacologic.

The disruptive effects of pain on n-back task performance in a large general population sample

Pain captures attention, displaces current concerns, and prioritises escape and repair. This attentional capture can be measured by its effects on general cognition. Studies on induced pain, naturally occurring acute pain, and chronic pain all demonstrate a detrimental effect on specific tasks of attention, especially those that involve working memory. However, studies to date have relied on relatively small samples and/or one type of pain, thus restricting our ability to generalise to wider populations. We investigated the effect of pain on an n-back task in a large heterogeneous sample of 1318 adults. Participants were recruited from the general population and tested through the internet. Despite the heterogeneity of pain conditions, participant characteristics, and testing environments, we found a performance decrement on the n-back task for those with pain, compared with those without pain; there were significantly more false alarms on nontarget trials. Furthermore, we also found an effect of pain intensity; performance was poorer in participants with higher intensity compared with that in those with lower intensity pain. We suggest that the effects of pain on attention found in the laboratory occur in more naturalistic settings. Pain is common in the general population, and such interruption may have important, as yet uninvestigated, consequences for tasks of everyday cognition that involve working memory, such as concentration, reasoning, motor planning, and prospective memory.

Fearful thinking predicts hypervigilance towards pain-related stimuli in patients with chronic pain

Cognitive impairment plays a role in the development and maintenance of chronic pain. Patients with painful disorders are reported to show attentional biases toward pain-related information. However, these findings are controversial, and rarely has any study examined whether chronic pain patients have attentional biases to pain-related conditioned stimuli (CS). In this study, twenty-one patients diagnosed with trigeminal neuralgia (TN) were recruited from the neurosurgical department of a large urban general hospital. Sixteen family members and twenty-one pain-free volunteers were included as two separate control groups. Pain ratings, pain-related anxiety, general anxiety, and depression were measured in all subjects using questionnaires. Two dot probe tests were performed, one that used pictures of painful versus neutral faces as cues, and another that presented three types of CS as cues that predicted certain, uncertain, or no pain. Our results demonstrate that the TN patients showed attentional biases towards painful faces and the CSs that signaled uncertain pain. Moreover, the ratings of negative emotion about their pain conditions correlated significantly with the presence of attentional biases. The patients' close family members, however, displayed biases towards uncertain-pain CS. This study demonstrates that patients with chronic pain have increased attention towards pain-related information, and the fearful thinking about pain was positively correlated with this phenomenon.

Does cognitive functioning predict chronic pain? Results from a prospective surgical cohort

It is well established that chronic pain impairs cognition, particularly memory, attention and mental flexibility. Overlaps have been found between the brain regions involved in pain modulation and cognition, including in particular the prefrontal cortex and the anterior cingulate cortex, which are involved in executive function, attention and memory. However, whether cognitive function may predict chronic pain has not been investigated. We addressed this question in surgical patients, because such patients can be followed prospectively and may have no pain before surgery. In this prospective longitudinal study, we investigated the links between executive function, visual memory and attention, as assessed by clinical measurements and the development of chronic pain, its severity and neuropathic symptoms (based on the 'Douleur Neuropathique 4' questionnaire), 6 and 12 months after surgery (total knee arthroplasty for osteoarthritis or breast surgery for cancer). Neuropsychological tests included the Trail-Making Test A and B, and the Rey-Osterrieth Complex Figure copy and immediate recall, which assess cognitive flexibility, visuospatial processing and visual memory. Anxiety, depression and coping strategies were also evaluated. In total, we investigated 189 patients before surgery: 96% were re-evaluated at 6 months, and 88% at 12 months. Multivariate logistic regression (stepwise selection) for the total group of patients indicated that the presence of clinical meaningful pain at 6 and 12 months (pain intensity ≥ 3/10) was predicted by poorer cognitive performance in the Trail Making Test B (P = 0.0009 and 0.02 for pain at 6 and 12 months, respectively), Rey-Osterrieth Complex Figure copy (P = 0.015 and 0.006 for pain at 6 and 12 months, respectively) and recall (P = 0.016 for pain at 12 months), independently of affective variables. Linear regression analyses indicated that impaired scores on these tests predicted pain intensity (P < 0.01) and neuropathic symptoms in patients with pain (P < 0.05), although the strength of the association was less robust for neuropathic symptoms. These results were not affected by the type of surgery or presurgical pain, similar findings being obtained specifically for patients who initially had no pain. In conclusion, these findings support, for the first time, the notion that premorbid limited cognitive flexibility and memory capacities may be linked to the mechanisms of pain chronicity and probably also to its neuropathic quality. This may imply that patients with deficits in executive functioning or memory because of cerebral conditions have a greater risk of pain chronicity after a painful event.