Pain-related attentional processes: A systematic review of eye-tracking research

Telehealth and Virtual Reality Technologies in Chronic Pain Management: A Narrative Review

PURPOSE OF REVIEW

This review provides medical practitioners with an overview of the present and emergent roles of telehealth and associated virtual reality (VR) applications in chronic pain (CP) management, particularly in the post-COVID-19 healthcare landscape.

RECENT FINDINGS

Accumulated evidence points to the efficacy of now well-established telehealth modalities, such as videoconferencing, short messaging service (SMS), and mobile health (mHealth) applications in complementing remote CP care. More recently, and although still in early phases of clinical implementation, a wide range of VR-based interventions have demonstrated potential for improving the asynchronous remote management of CP. Additionally, VR-associated technologies at the leading edge of science and engineering, such as VR-assisted biofeedback, haptic technology, high-definition three-dimensional (HD3D) conferencing, VR-enabled interactions in a Metaverse, and the use of wearable monitoring devices, herald a new era for remote, synchronous patient-physician interactions. These advancements hold the potential to facilitate remote physical examinations, personalized remote care, and innovative interventions such as ultra-realistic biofeedback. Despite the promise of VR-associated technologies, several limitations remain, including the paucity of robust long-term effectiveness data, heterogeneity of reported pain-related outcomes, challenges with scalability and insurance coverage, and demographic-specific barriers to patient acceptability. Future research efforts should be directed toward mitigating these limitations to facilitate the integration of telehealth-associated VR into the conventional management of CP. Despite ongoing barriers to widespread adoption, recent evidence suggests that VR-based interventions hold an increasing potential to complement and enhance the remote delivery of CP care.

Experimental Pain Picture System (EPPS): Development and Validation

Pain-related pictures are useful for studying how individuals respond to pain-related stimulation. Such pictures can occasionally be found in databases for affective pictures. However, a validated database specifically for pain-related pictures is not available yet. In 2 experiments (N = 185 and 103, respectively), we developed and validated the Experimental Pain Pictures System (EPPS). In both experiments, negative valence, arousal, and painfulness ratings were compared between neutral-, sad-, and pain-related pictures. The pain-related pictures represented both deep and superficial somatic pain. Across the 2 experiments, pain-related pictures were judged as more negative, arousing, and painful than neutral pictures and more painful than sad pictures. The final EPPS contains 50 pictures of different painful events considered moderately to highly painful by participants. The EPPS is a valuable tool for studying pain-related responses, as it gives researchers a choice among many validated pictures depicting different types of pain, increasing the comparability between studies. PERSPECTIVE: This article presents the validation of the experimental pain pictures system, which consists of a set of pain-related pictures. The experimental pain pictures system is composed of pictures depicting different types of pain. Participants rated all the pictures as being negative, arousing, and painful.

Neurocognitive Mechanisms Underlying Attention Bias Towards Pain: Evidence From a Drift-Diffusion Model and Event-Related Potentials

Although combining computational modeling with event-related potentials (ERPs) can precisely characterize neurocognitive processes involved in attention bias, it has yet to be applied in the context of pain. Here, a hierarchical drift-diffusion model (DDM) along with ERPs was used to characterize the neurocognitive mechanisms underlying attention bias towards pain. A spatial cueing paradigm was adopted, in which the locations of targets were either validly or invalidly predicted by spatial cues related to pain or nonpain signals. DDM-derived nondecision time was shorter for targets validly cued by pain signals than by nonpain signals, thus indicating speeded attention engagement towards pain; drift rate was slower for targets invalidly cued by pain signals than by nonpain signals, reflecting slower attention disengagement from pain. The facilitated engagement towards pain was partially mediated by the enhanced lateralization of cue-evoked N1 amplitudes, which relate to the bottom-up, stimulus-driven processes of detecting threatening signals. On the other hand, the retarded disengagement from pain was partially mediated by the enhanced target-evoked anterior N2 amplitudes, which relate to the top-down, goal-driven processes of conflict monitoring and behavior regulating. These results demonstrated that engagement and disengagement components of pain-related attention bias are governed by distinct neurocognitive mechanisms. However, it remains possible that the findings are not pain-specific, but rather, are related to threat or aversiveness in general. This deserves to be further examined by adding a control stimulus modality. PERSPECTIVE: This study characterized the neurocognitive processes involved in attention bias towards pain through combining a hierarchical DDM and ERPs. Our results revealed distinctive neurocognitive mechanisms underlying engagement and disengagement components of attention bias. Future studies are warranted to examine whether our findings are pain-specific or not.

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

ABSTRACT

Information-processing biases such as attentional, interpretation, and memory biases are believed to play a role in exacerbating and maintaining chronic pain (CP). Evidence suggests that individuals with CP show attentional bias toward pain-related information. However, the selective attentional processes that underpin this bias are not always well outlined in the literature. To improve current understanding, a systematic review was performed using a descriptive synthesis of reaction time-based studies. A random-effects meta-analysis was added to explore whether the results of previous meta-analyses would be confirmed using studies with a larger sample size. For this review, 2008 studies were screened from 4 databases, of which 34 (participant n = 3154) were included in the review and a subset of 15 (participant n = 1339) were included in the meta-analysis. Review results were summarised by producing a descriptive synthesis for all studies. Meta-analysis results indicated a mild significant attentional bias toward sensory pain-related information (k = 15, g = 0.28, 95% CI [0.16, 0.39], I2 = 43.2%, P = 0.038), and preliminary evidence of significant moderate bias towards affective pain-related information (k = 3, g = 0.48, 95% CI [0.23, 0.72], I2 = 7.1%, P = 0.341) for CP groups compared with control groups. We explored the main tasks, stimuli, and CP subtypes used to address attentional biases and related processes. However, variation across studies did not allow for a decisive conclusion about the role of stimulus, task type, or related attentional processes. In addition, a table of CP attention-related models was produced and tested for reliability. Finally, other results and recommendations are discussed.

VR for Pain Relief

The present chapter explores how immersive virtual reality (VR) systems can be used for pain research and treatment. Pain is a universal, yet entirely subjective and multifaceted unpleasant experience. One of the earliest VR studies on pain highlighted the role of attention in pain modulation. However, the role of body representation in pain modulation has also been described as a crucial factor. Through virtual reality systems, it is possible to modulate both attention to pain and body representation. In this chapter, first we define how immersive VR can be used to create the illusion of being present in immersive VR environments and argue why VR can be an effective tool for distracting patients from acute pain. However, distraction seems to be less useful in chronic pain treatment. Chronic pain can be highly disabling and can significantly impact not only the sufferer's quality of life, but also their perceptions of the bodily self. Close neural connections between the body matrix and pain open a chance for influencing pain through bodily illusions. This chapter explores approaches to inducing body ownership illusions in VR and discusses how they have been applied in pain research. The present chapter also covers a set of practical indications and methodological caveats of immersive VR and solutions for overcoming them. Finally, we outline several promising future research directions and highlight several yet unexplored areas.

EXPRESS: Testing links between pain-related biases in visual attention and recognition memory: An eye-tracking study based on an impending pain paradigm

Although separate lines of research have evaluated pain-related biases in attention or memory, laboratory studies examining links between attention and memory for pain-related information have received little consideration. In this eye-tracking experiment, we assessed relations between pain-related attention biases (ABs) and recognition memory biases (MBs) among 122 pain-free adults randomly assigned to impending pain (n = 59) versus impending touch (n = 63) conditions wherein offsets of trials that included pain images were followed by subsequent possibly painful and non-painful somatosensory stimulation, respectively. Gaze biases of participants were assessed during presentations of pain-neutral (P-N) and happy-neutral (H-N) face image pairs within these conditions. Subsequently, condition differences in recognition accuracy for previously-viewed versus novel pained and happy face images were examined. Overall gaze durations were significantly longer for pain (versus neutral) faces that signaled impending pain than impending non-painful touch, particularly among the less resilient in the former condition. Impending pain cohorts also exhibited comparatively better recognition accuracy for both pained and happy face images. Finally, longer gaze durations on pain faces that signaled potential pain, but not potential touch, were related to more accurate recognition of previously-viewed pain faces. In sum, pain cues that signal potential personal discomfort maintain visual attention more fully and are subsequently recognized more accuracy than are pain cues that signal non-painful touch stimulation.

Eye movement pattern of attention bias to emotional stimuli in women with high premenstrual symptoms

BACKGROUND AND OBJECTIVES

Premenstrual Syndrome (PMS) refers to a group of symptoms linked to the menstrual cycle. Women with PMS have cognitive mode of rumination, which leads to their attention bias to emotional stimuli. This study investigated the biases for emotional information in women with high premenstrual symptoms (HPMS) compared with women with low premenstrual symptoms (LPMS).

METHODS

A total of 38 women with HPMS and 44 women with LPMS completed self-report questionnaires and a free viewing task with eye-tracking technology.

RESULTS

The questionnaire results indicate that women in the HPMS group had higher levels of rumination than those in the LPMS group. The eye-tracking results show that women in the HPMS group had an orientation bias towards negative emotional stimuli in the early cognitive process. In the late cognitive process, women in the HPMS group had accelerated attentional disengagement to positive emotional stimuli and difficult attentional disengagement to negative emotional stimuli. Further correlation analysis revealed positive relationships between the scores of initial fixation latency bias of positive pictures in premenstrual phase and the scores of symptom rumination in both groups and between the scores of initial fixation latency bias of positive pictures in premenstrual phase and the scores of brooding in HPMS group.

LIMITATIONS

This study used a retrospective questionnaire to assess the symptoms of PMS.

CONCLUSIONS

Women with HPMS had impaired attentional engagement and disengagement to emotional stimuli compared with women with LPMS, and it may be related to their cognitive mode of rumination.

Cognitive Biases in Type 2 Diabetes and Chronic Pain

The aim of the present study was to investigate the role of cognitive processing biases in Type 2 diabetes (T2D) and chronic pain, 2 conditions that are highly co-morbid. The final sample comprised 333 individuals (86 with T2D and chronic pain, 65 with chronic pain, 76 with T2D, 106 without any form of diabetes or pain). Participants completed questionnaires assessing pain and diabetes-related outcomes, as well as measures of interpretation bias, attentional bias, and attentional bias variability. In a 2 (pain status) x 2 (T2D status) x 3 (bias valence) ANOVA design, interpretation biases were found to be stronger in individuals with chronic pain than individuals without pain, although there were no differences according to T2D status. No group differences in attentional biases were found. Among individuals with T2D, greater interpretation bias was associated with better blood glucose control, but also greater fear of hypoglycemia. For individuals with chronic pain, greater interpretation bias and attentional bias variability was associated with worse pain outcomes. Whilst interpretation bias may be present in chronic pain, it also appears to indicate better glycemic control in individuals with T2D. These findings suggest a more dynamic approach to understanding cognitive bias is needed, to consider when these biases are more or less adaptive, so that they can be better harnessed to improve outcomes for individuals with T2D who experience chronic pain. PERSPECTIVE: These findings suggest that cognitive biases can be associated with psychopathology in chronic pain and in T2D, but can also potentially be adaptive in those with T2D. Diabetes management interventions may require a careful balance between promoting sufficient concern to motivate engagement in adaptive diabetes self-management, whilst also minimizing fear of hypoglycemia.

The effects of attentional and interpretation biases on later pain outcomes among younger and older adults: A prospective study

BACKGROUND

Studies examining the effect of biased cognitions on later pain outcomes have primarily focused on attentional biases, leaving the role of interpretation biases largely unexplored. Also, few studies have examined pain-related cognitive biases in elderly persons. The current study aims to fill these research gaps.

METHODS

Younger and older adults with and without chronic pain (N = 126) completed an interpretation bias task and a free-viewing task of injury and neutral scenes at baseline. Participants' pain intensity and disability were assessed at baseline and at a 6-month follow-up. A machine-learning data-driven approach to analysing eye movement data was adopted.

RESULTS

Eye movement analyses revealed two common attentional pattern subgroups for scene-viewing: an "explorative" group and a "focused" group. At baseline, participants with chronic pain endorsed more injury-/illness-related interpretations compared to pain-free controls, but they did not differ in eye movements on scene images. Older adults interpreted illness-related scenarios more negatively compared to younger adults, but there was also no difference in eye movements between age groups. Moreover, negative interpretation biases were associated with baseline but not follow-up pain disability, whereas a focused gaze tendency for injury scenes was associated with follow-up but not baseline pain disability. Additionally, there was an indirect effect of interpretation biases on pain disability 6 months later through attentional bias for pain-related images.

CONCLUSIONS

The present study provided evidence for pain status and age group differences in injury-/illness-related interpretation biases. Results also revealed distinct roles of interpretation and attentional biases in pain chronicity.

SIGNIFICANCE

Adults with chronic pain endorsed more injury-/illness-related interpretations than pain-free controls. Older adults endorsed more illness interpretations than younger adults. A more negative interpretation bias indirectly predicted pain disability 6 months later through hypervigilance towards pain.

Examining attentional biases, interpretation biases, and attentional control in people with and without chronic pain

ABSTRACT

Psychological models of chronic pain (CP) highlight cognitive-processing biases (ie, attentional biases, interpretation biases, and attentional control) as pivotal processes that uniquely and synergistically impact the development and maintenance of CP. Very few studies explore multiple cognitive biases, and no studies have examined these 3 processes together in a CP sample. Furthermore, there is a lack of research investigating the relationship between these cognitive processes and pain-relevant variables (eg, pain intensity and pain catastrophising). The current study aimed to (1) compare attentional biases, interpretation biases, and attentional control in people with and without CP, (2) explore their interrelationships, and (3) explore their association with pain-related variables. Seventy-four participants with CP and 66 without pain volunteered. Participants completed a visual scanning task with eye tracking, a recognition task, and a flanker task. Traditional and Bayesian analysis indicated no effect of pain status on cognitive-processing biases. All participants, regardless of pain status, demonstrated attentional biases towards pain on some indices of early and late attention, but not interpretation bias or attentional control. There was weak evidence of associations between attentional biases, interpretation biases, and attentional control. Pain intensity was significantly correlated with interpretation biases, and follow-up analyses revealed people with high pain intensity demonstrated an interpretation bias towards pain significantly more than those with low pain intensity. Findings suggest that attentional biases towards pain are ubiquitous, but for people with moderate-to-severe pain, interpretation biases may have a role worthy of further research.

Do people with acute low back pain have an attentional bias to threat-related words?

OBJECTIVES

It has been hypothesised that attentional bias to environmental threats can contribute to persistent pain. It is unclear whether people with acute low back pain (LBP) have an attentional bias to environmental threats. We investigated if attentional bias of threat related words is different in people with acute LBP and pain-free controls.

METHODS

People with acute LBP and pain-free people completed a free viewing eye tracking task. Participants were simultaneously presented with two words, a threat related word and a neutral control word. Threat related words were general threat, affective pain and sensory pain. We conducted linear mixed models to detect differences between acute LBP and pain-free participants on five eye tracking outcome measures (dwell time, first fixation, latency to first fixation, first run dwell time and number of fixations). We calculated absolute reliability, (standard error of measure), and relative reliability (intraclass correlation coefficients [ICC 2,1]) for each eye tracking outcome measures.

RESULTS

We recruited 65 people with acute LBP and 65 pain-free controls. Participants with acute LBP had a higher proportion of fixations towards the affective pain words (M=0.5009, 95% CI=0.4941, 0.5076) than the pain-free controls had (M=0.4908, 95% CI=0.4836, 0.4979), mean between group difference = -0.0101, 95% CI [-0.0198, -0.0004], p=0.0422. There was no difference between acute LBP and pain-free controls for the remaining eye tracking outcome measures (all p>0.05). The only outcome measure that had an ICC of more than 0.7 was the latency to first fixation (affective pain words ICC=0.73, general threat words ICC=0.72).

CONCLUSIONS

When compared with pain-free controls, people with acute LBP looked more often at affective pain words relative to neutral control words. This may indicate a form of engagement bias for people with acute LBP. Attentional bias was not consistent across outcome measures or word groups. Further research is needed to investigate the potential role of attentional bias in the development of persistent pain.