ORCID Profile
0000-0001-7693-4158
Current Organisations
Griffith University
,
Bond University
,
University of South Australia
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Publisher: PeerJ
Date: 22-02-2017
DOI: 10.7717/PEERJ.3023
Abstract: Illusions that alter perception of the body provide novel opportunities to target brain-based contributions to problems such as persistent pain. One ex le of this, mirror therapy, uses vision to augment perceived movement of a painful limb to treat pain. Since mirrors can’t be used to induce augmented neck or other spinal movement, we aimed to test whether such an illusion could be achieved using virtual reality, in advance of testing its potential therapeutic benefit. We hypothesised that perceived head rotation would depend on visually suggested movement. In a within-subjects repeated measures experiment, 24 healthy volunteers performed neck movements to 50 o of rotation, while a virtual reality system delivered corresponding visual feedback that was offset by a factor of 50%–200%—the Motor Offset Visual Illusion (MoOVi)—thus simulating more or less movement than that actually occurring. At 50 o of real-world head rotation, participants pointed in the direction that they perceived they were facing. The discrepancy between actual and perceived direction was measured and compared between conditions. The impact of including multisensory (auditory and visual) feedback, the presence of a virtual body reference, and the use of 360 o immersive virtual reality with and without three-dimensional properties, was also investigated. Perception of head movement was dependent on visual-kinaesthetic feedback ( p = 0.001, partial eta squared = 0.17). That is, altered visual feedback caused a kinaesthetic drift in the direction of the visually suggested movement. The magnitude of the drift was not moderated by secondary variables such as the addition of illusory auditory feedback, the presence of a virtual body reference, or three-dimensionality of the scene. Virtual reality can be used to augment perceived movement and body position, such that one can perform a small movement, yet perceive a large one. The MoOVi technique tested here has clear potential for assessment and therapy of people with spinal pain.
Publisher: Oxford University Press (OUP)
Date: 14-12-2016
DOI: 10.1093/PM/PNV044
Abstract: Clinical scenarios of repeated pain usually involve both nociceptive and non-nociceptive input. It is likely that associations between these stimuli are learned over time. Such learning may underlie subsequent lification of pain, or evocation of pain in the absence of nociception. We undertook a systematic review and meta-analysis to evaluate the evidence that allodynia or hyperalgesia can be a classically conditioned response. A sensitive search of the literature covered Medline, Embase, CINAHL, AMED, PubMed, Scopus, PsycArticles, PsycINFO, Cochrane Library, and Web of Science. Additional studies were identified by contacting experts and searching published reviews. Two reviewers independently assessed studies for inclusion, evaluated risk of bias, and extracted data. Studies were included if they aimed to elicit or lify pain using a classical conditioning procedure in healthy, adult humans. Studies were excluded if they did not distinguish between classical conditioning and explicit verbal suggestion as learning sources, or did not use experiential learning. Thirteen studies, with varying risk of bias, were included. Ten studies evaluated classically conditioned hyperalgesia: nine found hyperalgesia one did not. Pooled effects (n = 8 with full data) showed a significant pain increase after conditioning (mean difference of 7.40 [95%CI: 4.00-10.80] on a 0-100 pain scale). Three studies evaluated conditioned allodynia and found conflicting results. The existing literature suggests that classical conditioning can lify pain. No conclusions can be drawn about whether or not classical conditioning can elicit pain. Rigorous experimental conditioning studies with nociceptive unconditioned stimuli are needed to fill this gap in knowledge.
Publisher: Informa UK Limited
Date: 18-10-2022
DOI: 10.1080/17483107.2022.2129846
Abstract: In virtual reality, avatar embodiment can spur perceptions and behaviours related the avatars' characteristics. We tested whether embodying superhero-like avatars can change self-perceptions in people with chronic low back pain (CLBP). A non-blinded pilot randomized controlled trial. Participants were randomly allocated to embody a superhero (VR-SH, The VR-SH group reported gains in body image during ( A VR-SH session produced temporary positive effects on body image. Future research may consider whether larger and sustained effects can be obtained with multisession exposures or explore combined interventions. Implications for rehabilitationPhysical confidence and bodily trust can be significantly enhanced in people with chronic back pain using virtual reality.These positive body image effects may have implications for rehabilitation, such as in enhancing confidence with movementWhether a multisession intervention might produce more robust effects and changes in pain is yet to be determined.
Publisher: Wiley
Date: 15-04-2014
Publisher: Walter de Gruyter GmbH
Date: 30-04-2018
Abstract: Pain is not a linear result of nociception, but is dependent on multisensory inputs, psychological factors, and prior experience. Since nociceptive models appear insufficient to explain chronic pain, understanding non-nociceptive contributors is imperative. Several recent models propose that cues associatively linked to painful events might acquire the capacity to augment, or even cause, pain. This experiment aimed to determine whether contexts associated with pain, could modulate mechanical pain thresholds and pain intensity. Forty-eight healthy participants underwent a contextual conditioning procedure, where three neutral virtual reality contexts were paired with either unpredictable noxious stimulation, unpredictable vibrotactile stimulation, or no stimulation. Following the conditioning procedure, mechanical pain thresholds and pain evoked by a test stimulus were examined in each context. In the test phase, the effect of expectancy was equalised across conditions by informing participants when thresholds and painful stimuli would be presented. Contrary to our hypothesis, scenes that were associated with noxious stimulation did not increase mechanical sensitivity ( p =0.08), or increase pain intensity ( p =0.46). However, an interaction with sex highlighted the possibility that pain-associated contexts may alter pain sensitivity in females but not males ( p =0.03). Overall, our data does not support the idea that pain-associated contexts can alter pain sensitivity in healthy asymptomatic in iduals. That an effect was shown in females highlights the possibility that some subgroups may be susceptible to such an effect, although the magnitude of the effect may lack real-world significance. If pain-associated cues prove to have a relevant pain augmenting effect, in some subgroups, procedures aimed at extinguishing pain-related associations may have therapeutic potential.
Publisher: SAGE Publications
Date: 15-03-2017
Abstract: Investigating psychological mechanisms that modulate pain, such as those that might be accessed by manipulation of context, is of great interest to researchers seeking to better understand and treat pain. The aim of this study was to better understand the interaction between pain sensitivity, and contexts with inherent emotional and social salience – by exploiting modern immersive virtual reality (VR) technology. A within-subjects, randomised, double-blinded, repeated measures (RM) design was used. In total, 25 healthy participants were exposed to neutral, pleasant, threatening, socially positive and socially negative contexts, using an Oculus Rift DK2. Pressure pain thresholds (PPTs) were recorded in each context, as well as prior to and following the procedure. We also investigated whether trait anxiety and pain catastrophisation interacted with the relationship between the different contexts and pain. Pressure pain sensitivity was not modulated by context ( p = 0.48). Anxiety and pain catastrophisation were not significantly associated with PPTs, nor did they interact with the relationship between context and PPTs. Contrary to our hypothesis, socially and emotionally salient contexts did not influence pain thresholds. In light of other research, we suggest that pain outcomes might only be tenable to manipulation by contextual cues if they specifically manipulate the meaning of the pain-eliciting stimulus, rather than manipulate psychological state generally – as per the current study. Future research might exploit immersive VR technology to better explore the link between noxious stimuli and contexts that directly alter its threat value.
Publisher: Elsevier BV
Date: 02-2021
Publisher: Elsevier BV
Date: 2015
DOI: 10.1016/J.JPAIN.2014.10.001
Abstract: Spatial summation of pain is well accepted but surprisingly understudied. Area-based summation refers to the increase in pain evoked by increasing the area of stimulation. Distance-based summation refers to the increase in pain evoked by increasing the distance between multiple stimuli. Although transcutaneous electrical stimulation has several advantages over other experimental pain paradigms, whether or not this modality evokes spatial summation remains unknown. We aimed to answer this question in order to lay the foundation for critical studies of spatial summation. Twenty-five healthy participants received stimuli on their forearm, and the primary outcome, pain intensity, was compared across 5 spatial configurations-1 with a single stimulus and 4 paired configurations at 0-, 5-, 10-, and 20-cm separations. Importantly, the potential confounder of a proximal-distal gradient in nociceptive sensitivity was removed in this study. Pain intensity was higher in response to the paired stimuli than in response to the single stimulus (P < .001), and the paired stimuli separated by 5, 10 and 20 cm, evoked greater pain than stimuli at a separation of 0 cm (P < .001), thus confirming both area- and distance-based summation, respectively. We conclude that transcutaneous electrical stimulation is appropriate for future investigations of spatial summation. Distance-based summation is likely implicated in some clinical pain. However, current understanding for spatial summation is limited. This study demonstrates that transcutaneous electrical stimulation is safe, feasible, and valid for future investigations of spatial summation and will allow critical questions to be answered.
Publisher: Elsevier BV
Date: 07-2017
DOI: 10.1016/J.CORTEX.2017.06.024
Abstract: Spatially-defined disruption of autonomic and sensory function has been identified in Complex Regional Pain Syndrome (CRPS). This study aimed to determine whether motor performance is also disrupted in a spatially-defined manner in people with CRPS. Thirteen people with CRPS type 1 of the upper limb participated in two motor experiments. In Experiment 1 participants performed a circle drawing task that primarily tested motor accuracy. In Experiment 2 participants performed a button pressing task that tested motor co-ordination. In both experiments the motor tasks were performed with either hand (affected or healthy), and on either side of the body midline - that is, on the affected side of space or healthy side of space. There was a main effect of both Limb and Side for the motor tasks. In Experiment 1, motor accuracy for the circle drawing task was poorer when participants used their affected hand than when they used their healthy one (p < .001), and when the task was performed on the affected side of their body midline than when it was performed on the healthy side (p < .001). In Experiment 2, motor co-ordination for the button pressing task was poorer when participants used their affected hand than when they used their healthy one (p < .001), and when the task was performed on the affected side of the midline (p < .001), as compared to the healthy side of the midline. Unilateral CRPS is associated with a spatially-defined disruption of motor performance. Participants perform worse when the task is performed on the affected side of the body midline, regardless of whether they use their affected or healthy hand.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 31-01-2022
DOI: 10.1097/J.PAIN.0000000000002605
Abstract: In this case report, we used virtual reality (VR) to explore pain evoked by only the appearance of being touched (rather than actually being touched) in a person with complex regional pain syndrome type II. Furthermore, we explored the degree to which this visually evoked pain could be extinguished by applying exposure principles in VR. In stage 1, we identified 4 specific scenarios where pain was triggered by visually simulated touch (without physical stimulation) and used these scenarios to quantify baseline sensitivity to visuotactile stimulation. In stage 2, the patient undertook a 12-week virtual exposure program, and the visual triggers were reassessed 3 weeks after the commencement and immediately upon completion of the program. At baseline, severe pain and a profound cold sensation were immediately and consistently evoked in concert with visually simulated touch. At 12-week follow-up, only one of the initially provocative visual stimuli triggered pain and only after 60 seconds of repeated stimulation. Unfortunately, the transfer of desensitisation from VR to the real world was limited. This case report describes the phenomena of visually evoked pain. Moreover, it describes the near complete extinguishing of visually evoked pain through virtual graded exposure. How improvements gained in VR might be better transferred to real-word improvements merits further investigation.
Publisher: Elsevier BV
Date: 11-2022
DOI: 10.1016/J.JPAIN.2022.07.008
Abstract: Over the last decade, the content, delivery and media of pain education have been adjusted in line with scientific discovery in pain and educational sciences, and in line with consumer perspectives. This paper describes a decade-long process of exploring consumer perspectives on pain science education concepts to inform clinician-derived educational updates (undertaken by the authors). Data were collected as part of a quality audit via a series of online surveys in which consent (non-specific) was obtained from consumers for their data to be used in published research. Consumers who presented for care for a persistent pain condition and were treated with a pain science education informed approach were invited to provide anonymous feedback about their current health status and pain journey experience 6, 12 or 18 months after initial assessment. Two-hundred eighteen consumers reported improvement in health status at follow-up. Results of the surveys from 3 cohorts of consumers that reported improvement were used to generate iterative versions of 'Key Learning Statements'. Early iteration of these Key Learning Statements was used to inform the development of Target Concepts and associated community-targeted pain education resources for use in public health and health professional workforce capacity building initiatives. PERSPECTIVE: This paper reflects an explicit interest in the insights of people who have been challenged by persistent pain and then recovered, to improve pain care. Identifying pain science concepts that consumers valued learning provided valuable information to inform resources for clinical interactions and community-targeted pain education c aigns.
Publisher: Frontiers Media SA
Date: 13-04-2021
DOI: 10.3389/FRVIR.2021.657761
Abstract: Chronic conditions represent a significant twenty first century challenge. Education and self-management training are the mainstay of clinical intervention for such conditions since care is dependent on health literacy and self-management. This intervention not only imparts the necessary understanding and skills for self-management, but also helps people to overcome personal barriers to positive behavioral change, such as low self-efficacy. Moreover, education maximizes dignity, by enabling shared decision-making. A plethora of research supports the role of education and self-management training in the management of chronic conditions, whilst at the same time highlighting that not all approaches lead to meaningful behavioral change. Immersive virtual reality (VR) offers a unique set of features and tools for delivering these interventions. For ex le, the immersive nature focuses attention and promotes engagement the ability to simulate authentic and interactive real-world scenarios can be used to promote the benefits of active learning and the ability to facilitate embodiment of avatars with distinct appearance and capability can be used to bias new perceptions and behaviors in-line with the avatar's characteristics. Moreover, the ability to use VR independent of a clinician renders a potential solution to instances where significant barriers to healthcare access exist. This short perspective paper will discuss how VR may be used to host education and self-management interventions in the domain of chronic condition management. Further, it will outline considerations for developers and conclude with a call for the co-creation of new VR-based education and self-management interventions.
Publisher: SAGE Publications
Date: 27-06-2020
Abstract: Psychological variables contribute to pain- and injury-related outcomes. We examined the hypothesis that anatomical spread and intensity of persistent pain relate to anxiety-related variables: generalised anxiety, fear of pain and pain catastrophising. An online survey was used to gather data from 413 women with persistent pain (low back pain, n = 139 fibromyalgia syndrome, n = 95 neck pain, n = 55 whiplash, n = 41 rheumatoid arthritis, n = 37 migraine, n = 46). The spread and intensity of pain were assessed using the McGill pain chart and a Numerical Rating Scale. A Bayesian Structural Equation Model assessed if the intensity and spread of pain increased with anxiety-related variables. Men were also surveyed (n = 80), but the s le size was only sufficient for analysing if their data were consistent with the model for women. Across subgroups of women, one standard deviation increase in catastrophising, generalised anxiety and fear corresponded to 27%, 7% and −1% additional pain areas and a 1.1, 0 and –0.1 change in pain intensity (on 0–10 scale), respectively. Overall, our clinical significance criterion – a 30% shift in pain variable in relation to one standard deviation increase in psychological variable – was not met. However, in subgroups it was met for pain spread (low back pain, neck pain and migraine) and pain intensity (migraine and neck pain) in relation to pain catastrophising. The model generally had low goodness-of-fit to men. These data support a meaningful relationship between some anxiety-related variables and pain in women for some conditions. Since the model did not consistently fit the men, we may conclude that the relationships are moderated by sex. Clinician attention to psychological variables as potential contributing factors can be justified however, research is needed to understand the relationship and whether psychological treatment can reduce pain.
Publisher: MDPI AG
Date: 12-07-2023
Abstract: Background: The sensorimotor incongruence theory proposes that certain instances of pain result from conflicts in the brain’s sensorimotor networks. Indeed, injuries may cause abnormalities in afferent and cortical signaling resulting in such conflicts. Motion sickness also occurs in instances of incongruent sensorimotor data. It is possible that a sensory processing phenotype exists that predisposes people to both conditions. Aim: The aim of this study was to investigate whether participants with chronic pain recall greater susceptibility to motion sickness before chronic pain onset. Method: Data were collected via an online LimeSurvey. A self-report tendency toward motion sickness was measured using the Motion Sickness Susceptibility Questionnaire. Group differences were analysed using analysis of covariance methods. Results: 530 patients (low back pain, n = 198 neck pain, n = 59 whiplash-associated disorder, n = 72 fibromyalgia syndrome, n = 114 Migraine, n = 41) and 165 pain-free controls were surveyed. ANCOVA analysis, using sex and anxiety as covariates, suggested that childhood motion sickness susceptibility scores differed by group (F = 2.55 (6, 615), p = 0.019, (ηp2) = 0.024). Planned comparisons, with corrected p-values, suggested that childhood motion sickness was not statistically greater for low back pain, rheumatoid arthritis, migraine, neck pain or whiplash-associated disorder (ps 0.05), although scores were on average 27%, 42%, 47%, 48% and 58% higher, respectively. Childhood susceptibility was statistically higher in people with FMS (p = 0.018), with scores on average 83% higher than controls. ANCOVA analysis, using sex and anxiety as covariates, suggested that adult motion sickness susceptibility scores did not differ by group (F = 1.86 (6, 613), p = 0.086), although average scores were, on average, at least 33% higher in persistent pain groups. Conclusions: According to retrospective reporting, greater susceptibility to motion sickness appears to pre-date persistent pain in some conditions. This supports the possibility that motion sickness and chronic pain may, in some cases, have overlapping mechanisms related to the handling of incongruent sensorimotor data.
Publisher: Elsevier BV
Date: 09-2021
Publisher: Springer Science and Business Media LLC
Date: 11-02-2022
DOI: 10.1007/S00221-021-06285-4
Abstract: Innocuous cues that become associated with pain can enhance pain. This is termed classically conditioned hyperalgesia. The size of this effect varies under different conditions. We aimed to test whether the sensitising effect of pain-associated cues depends on the intensity of the paired test stimulus. To do this, two virtual reality environments were paired with either painful or non-painful vibrotactile stimuli in a counterbalanced fashion. The differential effect of the two environments was evaluated using pain intensity ratings of paired electrocutaneous test stimuli at three different intensity levels. Forty healthy participants were included in the study 30 participants experienced sufficient pain during the learning phase and were included in the main analysis. An effect of environment ( p = 0.014) and interaction between environment and test stimulus intensity was found ( p = 0.046). Only the most intense test stimulus was modulated by environment. While the effect was small, the results are consistent with the proposition that pain-associated cues may induce hyperalgesia to some degree, under certain conditions. In particular, results highlight the potential relevance of stimulus intensity during and after the initial painful experience. Further attention is needed to comprehensively understand the variables that impact classically conditioned hyperalgesia.
Publisher: Informa UK Limited
Date: 08-06-2016
Publisher: Elsevier BV
Date: 10-2014
DOI: 10.1016/J.JPAIN.2014.07.005
Abstract: Contingency learning, in particular the formation of danger beliefs, underpins conditioned fear and avoidance behavior, yet equally important is the formation of safety beliefs. That is, when threat beliefs and accompanying fear/avoidance spread to technically safe cues, it might cause disability. Indeed, such over generalization has been advanced as a trans-diagnostic pathologic marker, but it has not been investigated in chronic pain. Using a novel hand pain scenario contingency learning task, we tested the hypotheses that chronic hand pain patients demonstrate less differential pain expectancy judgments because of poor safety learning and demonstrate broader generalization gradients than healthy controls. Participants viewed digitized 3-dimensional hands in different postures presented in random order (conditioned stimulus [CS]) and rated the likelihood that a fictive patient would feel pain when moving the hand into that posture. Subsequently, the outcome (pain/no pain) was presented on the screen. One hand posture was followed by pain (CS+), another was not (CS-). Generalization was tested using novel hand postures (generalization stimuli) that varied in how similar they were to the original conditioned stimuli. Patients, but not healthy controls, demonstrated a contingency learning deficit determined by impaired safety learning, but not by exaggerated pain expectancy toward the CS+. Patients showed flatter, asymmetric generalization gradients than the healthy controls did, with higher pain expectancy for novel postures that were more similar to the original CS-. The results clearly uphold our hypotheses and suggest that contingency learning deficits might be important in the development and maintenance of the chronic pain-related disability. Chronic hand pain patients demonstrate 1) reduced differential contingency learning determined by a lack of safety belief formation, but not by exaggerated threat belief formation, and 2) flatter, asymmetric generalization gradients than the healthy controls.
Publisher: The Royal Australian College of General Practitioners
Date: 09-2018
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 08-11-2019
DOI: 10.1097/AJP.0000000000000780
Abstract: Body illusions have shown promise in treating some chronic pain conditions. We hypothesized that neck exercises performed in virtual reality (VR) with visual feedback of rotation lified would reduce persistent neck pain. In a multiple-baseline replicated single case series, 8 blinded in iduals with persistent neck pain completed a 4-phase intervention (initial n=12, 4 dropouts): (1) “baseline” (2) “VR” during which participants performed rotation exercises in VR with no manipulation of visual feedback (3) “VR enhanced” during which identical exercises were performed but visual feedback overstated the range of motion being performed (4) “follow-up.” Primary outcomes were twice-daily measures of pain-free range of motion and pain intensity. During the baseline and follow-up phases, measures were taken but no intervention took place. No differences in primary outcomes were found between VR and baseline, VR enhanced and VR, or VR enhanced and follow-up. Our hypothesis, that neck exercises performed in VR with visual feedback of rotation lified, would reduce persistent neck pain was not supported. Possible explanations and future directions are discussed.
Publisher: Informa UK Limited
Date: 10-2011
DOI: 10.2147/JMDH.S24595
Publisher: Informa UK Limited
Date: 21-07-2022
DOI: 10.1080/09593985.2022.2095313
Abstract: Embodying fit avatars in virtual reality (VR) is proposed as a possible treatment for cortical body representations and pain-related self-perceptions. To explore consumer perceptions of a novel VR intervention (VR-BiT) for chronic low back pain. Adults (n = 17, mean age(SD) = 52(14)) with chronic low back pain who had undergone a single session of VR-BiT as part of a randomized controlled trial underwent a semi-structured interview using open-ended questions. Interviews were audio-recorded, transcribed verbatim, and analyzed thematically. Data reduction identified four themes: clinically beneficial and beyond helping and hindering use desire for more and in idualized future. Participants experienced wide ranging effects, including improved physical self-efficacy, pain, ability to perform physical activity and psychological symptoms. The intervention was well tolerated, except for two reports of nausea, and a few participants indicating pain associated with unaccustomed movement. Most participants were motivated to use VR-BiT again, despite some having technical issues. Participants suggested that personalizing VR-BiT and regular use would be beneficial. There was strong consumer support for further use of VR-BiT. Future studies of VR-BiT effectiveness are warranted and should consider incorporating in idual user preferences, including people with erse pain presentations, and involving a multi-session design.
Publisher: PeerJ
Date: 11-2019
DOI: 10.7717/PEERJ.8006
Abstract: Stand-up paddle boarding (SUP) is a rapidly growing global aquatic sport, with increasing popularity among participants within recreation, competition and rehabilitation. To date, few scientific studies have focused on SUP. Further, there is no research examining the biomechanics of the SUP paddle stroke. The purpose of this study was to investigate whether variations in kinematics existed among experienced and inexperienced SUP participants using three-dimensional motion analysis. This data could be of significance to participants, researchers, coaches and health practitioners to improve performance and inform injury minimization strategies. A cross-sectional observational design study was performed with seven experienced and 19 inexperienced paddlers whereby whole-body kinematic data were acquired using a six-camera Vicon motion capture system. Participants paddled on a SUP ergometer while three-dimensional range of motion (ROM) and peak joint angles were calculated for the shoulders, elbows, hips and trunk. Mann–Whitney U tests were conducted on the non-normally distributed data to evaluate differences between level of expertise. Significant differences in joint kinematics were found between experienced and inexperienced participants, with inexperienced participants using greater overall shoulder ROM (78.9° ± 24.9° vs 56.6° ± 17.3°, p = 0.010) and less hip ROM than the experienced participants (50.0° ± 18.5° vs 66.4° ± 11.8°, p = 0.035). Experienced participants demonstrated increased shoulder motion at the end of the paddle stoke compared to the inexperienced participants (74.9° ± 16.3° vs 35.2° ± 28.5°, p = 0.001 minimum shoulder flexion) and more extension at the elbow (6.0° ± 9.2° minimum elbow flexion vs 24.8° ± 13.5°, p = 0.000) than the inexperienced participants. The results of this study indicate several significant kinematic differences between the experienced and inexperienced SUP participants. These variations in technique were noted in the shoulder, elbow and hip and are evident in other aquatic paddling sports where injury rates are higher in these joints. These finding may be valuable for coaches, therapists and participants needing to maximize performance and minimize injury risk during participation in SUP.
Publisher: Oxford University Press (OUP)
Date: 28-09-2016
DOI: 10.1093/PM/PNW221
Abstract: Associative learning has been proposed as a mechanism behind the persistence of pain after tissue healing. The simultaneous occurrence of nociceptive and non-nociceptive input during acute injury mimics the pairings thought to drive classical conditioning effects. However, empirical evidence for classically conditioned allodynia is lacking. We aimed to manipulate pain thresholds with a classical conditioning procedure that used non-nociceptive somatosensory stimuli as conditioned stimuli (CS) and nociceptive stimuli as unconditioned stimuli. We also explored the influence of gender, depression, anxiety, negative affect, and pain catastrophizing on the main manipulation. Thirty-four healthy humans participated in a differential classical conditioning procedure that used vibrotactile stimulations at two different locations as CS. In an acquisition phase, CS+ was paired with painful thermal stimulation, and CS- with nonpainful thermal stimulation. Heat pain threshold was assessed during paired heat-CS trials before and after acquisition. A 2 (time: 1 and 2) x 2 (condition: CS+ and CS-) repeated-measures analysis of variance compared pain thresholds before and after acquisition. Exploratory analyses explored the influence of gender, depression, anxiety, negative affect, and pain catastrophizing. Postexperiment questions investigated participants' awareness of the contingencies employed. The classical conditioning procedure did not alter pain thresholds. Exploratory analyses did not reveal any influence of in idual differences. Thirty of the 34 participants were unaware of the contingencies between stimuli. The results of this study provide no evidence that allodynia can be induced in healthy humans using a classical conditioning procedure with simultaneous timing.
Publisher: SAGE Publications
Date: 17-02-2015
Abstract: Pain is a protective perceptual response shaped by contextual, psychological, and sensory inputs that suggest danger to the body. Sensory cues suggesting that a body part is moving toward a painful position may credibly signal the threat and thereby modulate pain. In this experiment, we used virtual reality to investigate whether manipulating visual proprioceptive cues could alter movement-evoked pain in 24 people with neck pain. We hypothesized that pain would occur at a lesser degree of head rotation when visual feedback overstated true rotation and at a greater degree of rotation when visual feedback understated true rotation. Our hypothesis was clearly supported: When vision overstated the amount of rotation, pain occurred at 7% less rotation than under conditions of accurate visual feedback, and when vision understated rotation, pain occurred at 6% greater rotation than under conditions of accurate visual feedback. We concluded that visual-proprioceptive information modulated the threshold for movement-evoked pain, which suggests that stimuli that become associated with pain can themselves trigger pain.
Publisher: Elsevier BV
Date: 07-2019
DOI: 10.1016/J.MSKSP.2019.04.015
Abstract: Perception is not simply a carbon copy of the real world, but is subject to distortions that may reflect protective drive. This study aimed to investigate whether people with chronic shoulder pain show perceptual distortions of space and body that may promote protective behavior. Eighty-four people with shoulder pain and 51 healthy controls participated. Participants estimated (1) distances to points on a cork-board within and outside reaching distance, and (2) the perceived length of their own arms. A novel measure of movement-related pain was also used to determine whether movement-related pain relates to perceptual distortion. Overall, distance and arm length estimates did not differ between groups, nor did participants perceive their arms to be of different length. However, a moderate correlation between movement-related pain and the index of distance perception was found within the pain group, specifically for distance estimates to points within reach. Our results suggest that distorted perception is not a typical consequence of chronic shoulder pain however, that it may occur in cases where pain is strongly linked to movement. Our findings have implications for understanding avoidance of movement in people with persistent pain.
Publisher: Wiley
Date: 04-03-2016
DOI: 10.1002/ANA.24616
Abstract: Pathological limb pain patients show decreased attention to some stimuli on the painful limb and increased attention to others, a paradox that has dogged the field for over a decade. We hypothesized that pathological pain involves a spatial inattention confined to bodily representations. Patients showed inattention to the painful side for visual processing of body parts but not letters, tactile processing but not auditory, and body-part bisection tasks but not line bisection tasks. We propose the new term "somatospatial inattention" to describe bodily-specific spatial inattention associated with pathological limb pain.
Publisher: Elsevier BV
Date: 09-2015
DOI: 10.1016/J.BETH.2015.02.004
Abstract: Recent research suggests that the mere intention to perform a painful movement can elicit pain-related fear. Based on these findings, the present study aimed to determine whether imagining a movement that is associated with pain (CS+) can start to elicit conditioned pain-related fear as well and whether pain-related fear elicited by imagining a painful movement can spread towards novel, similar but distinct imagined movements. We proposed a new experimental paradigm that integrates the left-right hand judgment task (HJT) with a differential fear conditioning procedure. During Acquisition, one hand posture (CS+) was consistently followed by a painful electrocutaneous stimulus (pain-US) and another hand posture (CS-) was not. Participants were instructed to make left-right judgments, which involve mentally rotating their own hand to match the displayed hand postures (i.e., motor imagery). During Generalization, participants were presented with a series of novel hand postures with six grades of perceptual similarity to the CS+ (generalization stimuli GSs). Finally, during Extinction, the CS+ hand posture was no longer reinforced. The results showed that (1) a painful hand posture triggers fear and increased US-expectancy as compared to a nonpainful hand posture, (2) this pain-related fear spreads to similar but distinct hand postures following a generalization gradient, and subsequently, (3) it can be successfully reduced during extinction. These effects were apparent in the verbal ratings, but not in the startle measures. Because of the lack of effect in the startle measures, we cannot draw firm conclusions about whether the "imagined movements" (i.e., motor imagery of the hand postures) gained associative strength rather than the hand posture pictures itself. From a clinical perspective, basic research into generalization of pain-related fear triggered by covert CSs such as intentions, imagined movements and movement-related cognitions might further our understanding of how pain and fear avoidance spread and persevere.
Publisher: Cambridge University Press (CUP)
Date: 30-05-2022
Abstract: Deficits in visuospatial attention, known as neglect, are common following brain injury, but underdiagnosed and poorly treated, resulting in long-term cognitive disability. In clinical settings, neglect is often assessed using simple pen-and-paper tests. While convenient, these cannot characterise the full spectrum of neglect. This protocol reports a research programme that compares traditional neglect assessments with a novel virtual reality attention assessment platform: The Attention Atlas (AA). The AA was codesigned by researchers and clinicians to meet the clinical need for improved neglect assessment. The AA uses a visual search paradigm to map the attended space in three dimensions and seeks to identify the optimal parameters that best distinguish neglect from non-neglect, and the spectrum of neglect, by providing near-time feedback to clinicians on system-level behavioural performance. A series of experiments will address procedural, scientific, patient, and clinical feasibility domains. Analyses focuses on descriptive measures of reaction time, accuracy data for target localisation, and histogram-based raycast attentional mapping analysis which measures the in idual’s orientation in space, and inter- and intra-in idual variation of visuospatial attention. We will compare neglect and control data using parametric between-subjects analyses. We present ex le in idual-level results produced in near-time during visual search. The development and validation of the AA is part of a new generation of translational neuroscience that exploits the latest advances in technology and brain science, including technology repurposed from the consumer gaming market. This approach to rehabilitation has the potential for highly accurate, highly engaging, personalised care.
Publisher: PeerJ
Date: 25-10-2021
DOI: 10.7717/PEERJ.12192
Abstract: Reduced tactile acuity has been observed in several chronic pain conditions and has been proposed as a clinical indicator of somatosensory impairments related to the condition. As some interventions targeting these impairments have resulted in pain reduction, assessing tactile acuity may have significant clinical potential. While two-point discrimination threshold (TPDT) is a popular method of assessing tactile acuity, large measurement error has been observed (impeding responsiveness) and its validity has been questioned. The recently developed semi-automated ‘imprint Tactile Acuity Device’ (iTAD) may improve tactile acuity assessment, but clinimetric properties of its scores (accuracy score, response time and rate correct score) need further examination. Experiment 1: To determine inter-rater reliability and measurement error of TPDT and iTAD assessments. Experiment 2: To determine internal consistencies and floor or ceiling effects of iTAD scores, and investigate effects of age, sex, and anthropometry on performance. Experiment 1: To assess inter-rater reliability (ICC (2,1) ) and measurement error (coefficient of variation (CoV)), three assessors each performed TPDT and iTAD assessments at the neck in forty healthy participants. Experiment 2: To assess internal consistency (ICC (2,k) ) and floor or ceiling effects (skewness z-scores), one hundred healthy participants performed the iTAD’s localisation and orientation tests. Balanced for sex, participants were equally ided over five age brackets (18–30, 31–40, 41–50, 51–60 and 61–70). Age, sex, body mass index (BMI) and neck surface area were assessed to examine their direct (using multiple linear regression analysis) and indirect (using sequential mediation analysis) relationship with iTAD scores. Mean ICC (2,1) was moderate for TPDT (0.70) and moderate-to-good for the various iTAD scores (0.65–0.86). The CoV was 25.3% for TPDT and ranged from 6.1% to 16.5% for iTAD scores. Internal consistency was high for both iTAD accuracy scores (ICC (2,6) = 0.84 ICC (2,4) = 0.86). No overt floor or ceiling effects were detected (all skewness z-scores 3.29). Accuracy scores were only directly related to age (decreasing with increasing age) and sex (higher for men). Although reliability was similar, iTAD scores demonstrated less measurement error than TPDT indicating a potential for better responsiveness to treatment effects. Further, unlike previously reported for TPDT, iTAD scores appeared independent of anthropometry, which simplifies interpretation. Additionally, the iTAD assesses multiple aspects of tactile processing which may provide a more comprehensive evaluation of tactile acuity. Taken together, the iTAD shows promise in measuring tactile acuity, but patient studies are needed to verify clinical relevance.
Publisher: Frontiers Media SA
Date: 29-09-2022
Publisher: Elsevier BV
Date: 08-2017
DOI: 10.1016/J.JPAIN.2017.02.430
Abstract: Prominent clinical models of chronic pain propose a fundamental role of classical conditioning in the development of pain-related disability. If classical conditioning is key to this process, then people with chronic pain may show a different response to pain-related conditioned stimuli than healthy control subjects. We set out to determine whether this is the case by undertaking a comprehensive and systematic review of the literature. To identify studies comparing classical conditioning between people with chronic pain and healthy control subjects, the databases MEDLINE, PsychINFO, PsychARTICLES, Scopus, and CINAHL were searched using key words and medical subject headings consistent with 'classical conditioning' and 'pain.' Articles were included when: 1) pain-free control and chronic pain groups were included, and 2) a differential classical conditioning design was used. The systematic search revealed 7 studies investigating differences in classical conditioning between people with chronic pain and healthy control participants. The included studies involved a total of 129 people with chronic pain (fibromyalgia syndrome, spinal pain, hand pain, irritable bowel syndrome), and 104 healthy control participants. Outcomes included indices of pain-related conditioning such as unconditioned stimulus (US) expectancy and contingency awareness, self-report and physiological measures of pain-related fear, evaluative judgements of conditioned stimulus pleasantness, and muscular and cortical responses. Because of variability in outcomes, meta-analyses included a maximum of 4 studies. People with chronic pain tended to show reduced differential learning and flatter generalization gradients with respect to US expectancy and fear-potentiated eyeblink startle responses. Some studies showed a propensity for greater muscular responses and perceptions of unpleasantness in response to pain-associated cues, relative to control cues. The review revealed preliminary evidence that people with chronic pain may exhibit less differential US expectancy and fear learning. This characteristic may contribute to widespread fear-avoidance behavior. The assumption that altered classical conditioning may be a predisposing or maintaining factor for chronic pain remains to be verified.
Publisher: Walter de Gruyter GmbH
Date: 04-2016
DOI: 10.1016/J.SJPAIN.2015.09.007
Abstract: Non-nociceptive somatosensory input, such as tactile or proprioceptive information, alway precedes nociceptive input during a painful event. This relationship provides clear opportunities fo predictive associative learning, which may shape future painful experiences. In this differential classica conditioning study we tested whether pain-associated tactile cues (conditioned stimuli CS) could altei the perceived intensity of painful stimulation, and whether this depends on duration of the CS—seeing that CS duration might allow or prevent conscious expectation. Subjects underwent a classical differential conditioning task in which a tactile cue at locatior A (CS+) preceded painful electrical stimulation at location B (UShigh), whereas a tactile cue at location C (CS–) preceded non-painful electrical stimulation at location B (USlow). At test, we compared the pain evoked by a moderately painful stimulus (USmed) when preceded by either the CS+ or CS–. CS duration was manipulated between subjects. Participants were assigned to one of three groups: Long CS (4s, allowing conscious expectation), Short CS (110 ms) and CS-US indistinguishable (20 ms), preventing conscious expectation). We hypothesised that more pain would be evoked by the US when preceded by the CS+ relative to the CS-, and that the effect would be independent of CS duration. Fifty-four healthy participants (31 females, age = 26, SD = 9) were included in the analysis. The hypotheses were supported in that more intense pain was evoked by the USmed when paired with the tactile CS+, than when paired with the tactile CS- mean difference 3 mm on a 150 mm VAS (C 0.4-4.8 mm). CS duration did not moderate the effect. The effect was greater in those participants where calibration was optimal, as indicated by a relatively more painful UShigh. We conclude that pain-associated tactile cues can influence pain, and that this effect i: not dependent on stimulus duration. This suggests that explicit expectation is not a requirement for predictive cues to modulate pain. That the presence of the CS+ resulted in only a 5.3% higher intensity rating compared with the CS- may reflect a limitation of laboratory studies, where a limited number o trials, an artificial context and the use of experimental pain are likely to reveal only glimpses of what i: clinically possible. Pain-associated visual and auditory cues have been shown to enhance pain in laboratory and clinical scenarios, supposedly by influencing expectation of impending harm. We show that pain-associated somatosensory cues can also modulate pain and that this can occur independently of expectation. This points to a larger potential role for associative learning in the development and treatment of pain than has previously been considered. We suggest that research into associative mechanisms underpinning pain, as distinct from those that link pain to pain-related fear and avoidance, is worthwhile.
Publisher: Wiley
Date: 07-03-2016
DOI: 10.1111/PSYP.12631
Abstract: Learning to initiate defenses in response to specific signals of danger is adaptive. Some chronic pain conditions, however, are characterized by widespread anxiety, avoidance, and pain consistent with a loss of defensive response specificity. Response specificity depends on ability to discriminate between safe and threatening stimuli therefore, specificity might depend on sensory precision. This would help explain the high prevalence of chronic pain in body areas of low tactile acuity, such as the lower back, and clarify why improving sensory precision may reduce chronic pain. We compared the acquisition and generalization of fear of pain-associated vibrotactile stimuli delivered to either the hand (high tactile acuity) or the back (low tactile acuity). During acquisition, tactile stimulation at one location (CS+) predicted the noxious electrocutaneous stimulation (US), while tactile stimulation at another location (CS-) did not. Responses to three stimuli with decreasing spatial proximity to the CS+ (generalizing stimuli GS1-3) were tested. Differential learning and generalization were compared between groups. The main outcome of fear-potentiated startle responses showed differential learning only in the hand group. Self-reported fear and expectancy confirmed differential learning and limited generalization in the hand group, and suggested undifferentiated fear and expectancy in the back group. Differences in generalization could not be inferred from the startle data. Specificity of fear responses appears to be affected by somatosensory precision. This has implications for our understanding of the role of sensory imprecision in the development of chronic pain.
Publisher: Elsevier BV
Date: 02-2018
DOI: 10.1016/J.MSKSP.2017.11.009
Abstract: Tactile acuity deficits have been demonstrated in a range of persistent pain conditions and may reflect underlying cortical re-organisation. This study aimed to determine whether tactile acuity is impaired in people with chronic neck pain relative to controls, and whether deficits relate to pain location, duration and intensity. In this cross-sectional study, 20 people with chronic neck pain (5 idiopathic neck pain 15 whiplash-associated disorder) and 20 pain-free controls underwent two-point discrimination (TPD) testing at the neck, back and arm, and point-to-point (PTP) and graphesthesia tests of tactile acuity at the neck and arm. Linear mixed effects models demonstrated a significant group*body region interaction for TPD, Graphesthesia and PTP tests (Ps < 0.001), with post hoc tests showing impaired TPD in people with neck pain relative to controls at the neck, low back, and arm (P ≤ 0.001). Graphesthesia and PTP was also impaired at the neck (P < 0.001) but not the arm (P ≥ 0.48). TPD correlated with intensity and duration of pain (Pearson's r = 0.48, P < 0.05 Pearson's r = 0.77, P < 0.01). There was no sig difference between the two neck pain groups for any tactile acuity measure (TPD: P = 0.054 Graphesthesia P = 0.67 Point to Point: P = 0.77), however, low power limited confidence in this comparison. People with chronic neck pain demonstrated tactile acuity deficits in painful and non-painful regions when measured using the TPD test, with the magnitude of deficits appearing greatest at the neck. The study also revealed a positive relationship between TPD and pain intensity/duration, further supporting the main study finding.
Publisher: PeerJ
Date: 23-06-2020
DOI: 10.7717/PEERJ.9345
Abstract: Learning to predict threatening events enables an organism to engage in protective behavior and prevent harm. Failure to differentiate between cues that truly predict danger and those that do not, however, may lead to indiscriminate fear and avoidance behaviors, which in turn may contribute to disability in people with persistent pain. We aimed to test whether people with persistent neck pain exhibit contingency learning deficits in predicting pain relative to pain-free, gender-and age-matched controls. We developed a differential predictive learning task with a neck pain-relevant scenario. During the acquisition phase, images displaying two distinct neck positions were presented and participants were asked to predict whether these neck positions would lead to pain in a fictive patient with persistent neck pain (see fictive patient scenario details in Appendix A). After participants gave their pain-expectancy judgment in the hypothetical scenario, the verbal outcome (PAIN or NO PAIN) was shown on the screen. One image (CS+) was followed by the outcome “PAIN”, while another image (CS−) was followed by the outcome “NO PAIN”. During the generalization phase, novel but related images depicting neck positions along a continuum between the CS+ and CS− images (generalization stimuli GSs) were introduced to assess the generalization of acquired predictive learning to the novel images the GSs were always followed by the verbal outcome “NOTES UNREADABLE” to prevent extinction learning. Finally, an extinction phase was included in which all images were followed by “NO PAIN” assessing the persistence of pain-expectancy judgments following disconfirming information. Differential pain-expectancy learning was reduced in people with neck pain relative to controls, resulting from patients giving significantly lower pain-expectancy judgments for the CS+, and significantly higher pain-expectancy judgments for the CS−. People with neck pain also demonstrated flatter generalization gradients relative to controls. No differences in extinction were noted. The results support the hypothesis that people with persistent neck pain exhibit reduced differential pain-expectancy learning and flatter generalization gradients, reflecting deficits in predictive learning. Contrary to our hypothesis, no differences in extinction were found. These findings may be relevant to understanding behavioral aspects of chronic pain.
Publisher: Wiley
Date: 25-03-2013
Publisher: Elsevier BV
Date: 12-2017
DOI: 10.1016/J.MSKSP.2017.07.007
Abstract: Interest in measurement of tactile acuity in musculoskeletal practice has emerged following its link to functional reorganization of the somatosensory cortex in ongoing pain states. Several tactile acuity measurement methods have been described but have not been thoroughly investigated in the cervical region. This study examined reliability, concurrent validity and responsiveness of four tests of tactile acuity-Two-point discrimination, Point-to-point, Graphesthesia, and Localisation tests-at the cervical region. Forty-two healthy participants were included. In Part 1 (n = 22), participants' tactile acuity was assessed at two time points, 30 min apart, to determine the test-retest reliability and concurrent validity of each of the tests. In Part 2 (n = 20), participants received five daily tactile training sessions, delivered via a vibro-tactile device. Tactile acuity was assessed pre- and post-training to examine responsiveness of each test. Two-point discrimination demonstrated excellent test-retest reliability (ICC = 0.85, SEM = 3.7 mm), Point-to-point and Localisation tests demonstrated good reliability (ICC = 0.60, SEM = 2.8 mm ICC = 0.60, SEM = 8.8%), and Graphesthesia demonstrated fair reliability (ICC = 0.48, SEM = 1.9/20). There was no significant correlation among measures. Only Graphesthesia failed to show responsiveness to change following training. The reliability of Two-point discrimination appears superior to other examined tests of tactile acuity, however measurement variability should be considered. Two-point discrimination, Point-to-point, and Localisation tests appear responsive to change, although testing in clinical s les is needed. The lack of concurrent validity among tests suggests that they cannot be used interchangeably.
Publisher: Oxford University Press (OUP)
Date: 05-2016
DOI: 10.2522/PTJ.20150210
Abstract: Proprioceptive imprecision is believed to contribute to persistent pain. Detecting imprecision in order to study or treat it remains challenging given the limitations of current tests. The aim of this study was to determine whether proprioceptive imprecision could be detected in people with neck pain by testing their ability to identify incongruence between true head motion and a false visual reference using the Proprioception Incongruence Detection (PID) Test. A cross-sectional study was conducted. Twenty-four people with neck pain and 24 matched controls repeatedly rotated to specific markers within a virtual world and indicated if their true head rotation was more or less than the rotation suggested by the visual feedback. Visual feedback was manipulated at 6 corrections, ranging from 60% of true movement to 140% of true movement. A standard repositioning error (RPE) test as undertaken for comparison. Healthy controls were better able to detect incongruence between vision and true head rotation (X̅=75.6%, SD=8.5%) than people with neck pain were (X̅=69.6%, SD=12.7%). The RPE test scores were not different between groups. The PID Test score related to self-reported pain intensity but did not relate to RPE test score. Causality cannot be established from this cross-sectional study, and further work refining the PID Test is needed for it to offer clinical utility. Proprioceptive precision for neck movement appears worse in people with neck pain than in those without neck pain, and the extent of the deficit appears to be related to usual pain severity. The PID Test appears to be a more sensitive test than the RPE test and is likely to be useful for assessment of proprioceptive function in research and clinical settings.
Publisher: Mary Ann Liebert Inc
Date: 10-2019
Abstract: Pain is an understudied and undertreated consequence of cancer survival. Pain education is now a recommended treatment approach for persistent non-cancer pain, yet it has not been well applied to the context of adolescent and young adult (AYA) cancer survival. In March 2018, an interdisciplinary meeting was held in Adelaide, South Australia to set a research agenda for pain education in AYA cancer survivors. We identified that AYAs with persistent pain and those with heightened pain-related fear have the potential to benefit from pain education. We identified a number of unique challenges of engaging AYA survivors in pain education, and point towards future research directions.
No related grants have been discovered for Daniel Harvie.