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The Journal of Pain 2020Avoidance is considered key in the development of chronic pain. However, little is known about how avoidance behavior subsequently affects pain-related fear and pain. We...
Avoidance is considered key in the development of chronic pain. However, little is known about how avoidance behavior subsequently affects pain-related fear and pain. We investigated this using a robotic arm reaching avoidance task. In a between-subjects design both Experimental Group (n = 30) and Yoked Control Group (n = 30) participants perform either of 3 movement trajectories (T1-T3) to reach a target location. During acquisition, only participants of the Experimental Group could partially or fully avoid a painful electrocutaneous stimulus by choosing the intermediate trajectory (T2; 50% reinforcement) or the longest trajectory (T3; 0% reinforcement) versus the shortest trajectory (T1: 100% reinforcement). After acquisition, contingencies changed (all trajectories 50% reinforced), and the acquired avoidance behavior no longer effectively prevented pain from occurring. The Yoked Control Group received the same reinforcement schedule as the Experimental Group irrespective of their behavior. When avoidance behavior became ineffective for the Experimental Group, pain-related fear increased for the previously safe(r) trajectories (T2 and T3) and remained the same for T1, whereas pain threshold and tolerance declined. For the Yoked Group, pain-related fear increased for all trajectories. The Experimental Group persisted in emitting avoidance behavior following the contingency change, albeit at a lower frequency than during acquisition. PERSPECTIVE: Results indicate participants become more afraid of and sensitive to pain, when previously acquired avoidance is no longer effective. Also, participants continue to show avoidance behavior despite it being not adaptive anymore. These findings suggest that ineffective avoidance may play role in the maintenance and development of chronic pain.
Topics: Adolescent; Adult; Arm; Avoidance Learning; Electric Stimulation; Fear; Female; Humans; Male; Middle Aged; Motor Activity; Nociceptive Pain; Pain Perception; Pain Threshold; Touch Perception; Young Adult
PubMed: 31541718
DOI: 10.1016/j.jpain.2019.09.002 -
Cyberpsychology, Behavior and Social... Dec 2020This experiment examined the effects of social presence and perceived location of a virtual environment on participants' pain thresholds in a preregistered,...
This experiment examined the effects of social presence and perceived location of a virtual environment on participants' pain thresholds in a preregistered, within-subjects experiment. First, we examined the effects of social interaction versus being alone in a virtual environment. Second, we compared a virtual environment representing a remote location to a replication of the laboratory environment. Social interaction predicted increased pain tolerance, but there was no effect of the "location" of the virtual environment. To our knowledge, this research project is the first to use real-time social interaction in virtual reality as a distractor for experimental thermal pain, and the first to examine the potential interaction between social interaction and transportation to different virtual locations. While this task is not directly analogous to the experience of pain in a medical setting, this preliminary study indicates future avenues for patient treatment. Clinical Trial Registration number: 1701006910.
Topics: Female; Humans; Male; Pain Management; Pain Threshold; Social Interaction; Virtual Reality
PubMed: 33179974
DOI: 10.1089/cyber.2020.0055 -
Scandinavian Journal of Pain Jan 2022Scientific evidence suggests that virtual reality (VR) could potentially help patients tolerate painful medical procedures and conditions. The aim of this study was to...
OBJECTIVES
Scientific evidence suggests that virtual reality (VR) could potentially help patients tolerate painful medical procedures and conditions. The aim of this study was to evaluate the efficacy of virtual reality on pain tolerance and threshold.
METHODS
A within-subjects experimental study design was conducted on 53 female students at Qassim University in Saudi Arabia. Each participant completed three rounds of assessment: one baseline (no VR) and two VR immersion (passive and interactive) in random order sequence. During each round, participants submerged their non-dominant hand into an ice bath; pain threshold and tolerance were measured as outcomes and analyzed using repeated measures ANOVA.
RESULTS
Participants had both higher pain threshold and tolerance during interactive and passive VR rounds in comparison to the non-VR baseline assessment (p<0.05). Participants had greater pain tolerance during the interactive VR condition compared to the passive VR condition (p<0.001).
CONCLUSIONS
VR experiences increase pain threshold and tolerance with minimal side effects, and the larger effects were demonstrated using interactive games. Interactive VR gaming should be considered and tested as a treatment for pain.
Topics: Female; Humans; Pain; Pain Management; Pain Measurement; Pain Threshold; Virtual Reality
PubMed: 34348422
DOI: 10.1515/sjpain-2021-0046 -
Scandinavian Journal of Pain Jul 2023Conditioned pain modulation is a commonly used quantitative sensory test, measuring endogenous pain control. The temporal stability of the test is questioned, and there... (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVES
Conditioned pain modulation is a commonly used quantitative sensory test, measuring endogenous pain control. The temporal stability of the test is questioned, and there is a lack of agreement on the effect of different pain conditions on the conditioned pain modulation response. Thus, an investigation of the temporal stability of a conditioned pain modulation test among patients suffering from persistent or recurrent neck pain is warranted. Further, an investigation into the difference between patients experiencing a clinically important improvement in pain and those not experiencing such an improvement will aid the understanding between changes in pain and the stability of the conditioned pain modulation test.
METHODS
This study is based on a randomized controlled trial investigating the effect of home stretching exercises and spinal manipulative therapy vs. home stretching exercises alone. As no difference was found between the interventions, all participants were studied as a prospective cohort in this study, investigating the temporal stability of a conditioned pain modulation test. The cohort was also divided into responders with a minimally clinically important improvement in pain and those not experiencing such an improvement.
RESULTS
Stable measurements of conditioned pain modulation were observed for all independent variables, with a mean change in individual CPM responses of 0.22 from baseline to one week with a standard deviation of 1.34, and -0.15 from the first to the second week with a standard deviation of 1.23. An Intraclass Correlation Coefficient (ICC3 - single, fixed rater) for CPM across the three time points yielded a coefficient of 0.54 (p<0.001).
CONCLUSIONS
Patients with persistent or recurrent neck pain had stable CPM responses over a 2 week course of treatment irrespective of clinical response.
Topics: Humans; Pain Threshold; Pain Measurement; Neck Pain; Prospective Studies; Pain Management
PubMed: 36869854
DOI: 10.1515/sjpain-2022-0084 -
Scandinavian Journal of Pain Jan 2023Paradoxical sensations, known as thermal pain illusions, can be evoked by painful cold-heat pulse stimulation. They may provide diagnostic value; however, the possible...
OBJECTIVES
Paradoxical sensations, known as thermal pain illusions, can be evoked by painful cold-heat pulse stimulation. They may provide diagnostic value; however, the possible interaction between conditioned pain modulation and thermal pain illusions has not been explored. The present study examined: (1) whether conditioned pain modulation could be induced by alternating tonic painful cold-heat pulse stimulation; and (2) whether the presence of thermal pain illusions during the conditioning stimulus influences the degree of conditioned pain modulation.
METHODS
This study was approved by the Ethics Committee of Meikai University (A1507). Conditioned pain modulation was provoked using alternating painful cold-heat pulses delivered at 20-s intervals applied to the forearm. Thermal pain illusions were qualitatively evaluated, and conditioned pain modulation was assessed quantitatively using the pressure pain threshold as a test stimulus. Differences in the conditioned pain modulation effect between the participants who experienced thermal pain illusions and those who did not were analysed using Student's -test.
RESULTS
A significant positive conditioned pain modulation effect (51.0 ± 4.7%, overall effect) was detected. There was no significant difference in conditioned pain modulation between the participants who experienced thermal pain illusions and those who did not (44.3 ± 6.0% and 55.5 ± 6.8%, respectively; p = 0.255).
CONCLUSIONS
Conditioned pain modulation induced by alternating painful conditioning cold-heat pulse stimulation was identical during the conditioning stimulation in volunteers with and without thermal pain illusions. Conditioning cold-heat pulse stimulation is useful to evaluate conditioned pain modulation. Moreover, conditioned pain modulation is not influenced by the presence of thermal pain illusions, indicating partially different underlying supraspinal, neuronal networks.
Topics: Humans; Illusions; Pain Measurement; Pain; Pain Threshold; Hot Temperature
PubMed: 35607757
DOI: 10.1515/sjpain-2022-0037 -
Journal of Affective Disorders Jan 2021Beta-endorphin (BE) has been suggested to play a central role as to why people engage in NSSI. To our knowledge, no study has systematically assessed this potential...
BACKGROUND
Beta-endorphin (BE) has been suggested to play a central role as to why people engage in NSSI. To our knowledge, no study has systematically assessed this potential relationship in adolescents with NSSI.
METHODS
94 adolescents with NSSI (according to DSM-5 criteria) and 35 healthy controls (HC) were enrolled. All participants received heat pain stimulation, with pain threshold and tolerance measured in °C. Plasma BE levels were assessed. Sociodemographic and clinical characteristics were obtained via semi-structured interviews and self-report questionnaires.
RESULTS
Adolescents with NSSI showed increased pain thresholds (t=2.071, p=.040), lower pain intensity (t==2.122, p=.036) and lower plasma BE levels (t==3.182, p=.002) compared to HC. Groups did not differ on pain tolerance (t=0.911, p=.364). Greater pain threshold correlated positively with borderline personality disorder (BPD) symptoms (r=0.182, p=.039), while pain intensity (r=-0.206, p=.033) and BE levels (r=-0.246, p=.007) correlated negatively with depression severity. No significant relationship was found between pain threshold and plasma BE (r=-0.013, p=.882).
LIMITATIONS
Future studies should implement repeated plasma BE measures to assess BE release in association with pain in NSSI. Validity of plasma BE measures compared to central measures should be considered. Assessing the association between pain sensitivity (PS) and BE in a naturalistic setting presents a promising avenue for future research in NSSI.
CONCLUSIONS
Findings support both reduced PS and basal opioid deficiency as independent biological correlates and potential risk-factors for NSSI. Further longitudinal and experimental studies are needed to investigate the role of BE levels and PS as well as their potential association.
Topics: Adolescent; Borderline Personality Disorder; Humans; Pain; Pain Threshold; Plasma; Self-Injurious Behavior; beta-Endorphin
PubMed: 32961416
DOI: 10.1016/j.jad.2020.09.036 -
European Journal of Applied Physiology Oct 2022Acute physical activity leads to exercise-induced hypoalgesia (EIH). The aim of this study was to investigate the effects of four different exercise intensities on EIH. (Randomized Controlled Trial)
Randomized Controlled Trial
PURPOSE
Acute physical activity leads to exercise-induced hypoalgesia (EIH). The aim of this study was to investigate the effects of four different exercise intensities on EIH.
METHODS
25 male (age: 24.7 ± 3.0) subjects underwent four different exercise sessions on a bicycle ergometer for 30 min each at 60, 80, 100, and 110% of the individual anaerobic threshold on separate days in a randomized crossover design. Before, as well as 5- and 45-min post-exercise, pain sensitivity was measured employing pain pressure thresholds (PPT) at the elbow, knee, and ankle joints as well as the sternum and forehead. Besides, conditioned pain modulation (CPM) was conducted using thermal test- and conditioned stimuli before, 5-, and 45-min post-exercise.
RESULTS
A main time effect was observed regarding PPT at all landmarks except for the forehead with higher values observed 5 and 45 min post-exercise compared to the pre-values. Yet, no interaction effects occurred. CPM did not change in response to any of the intensities used.
CONCLUSION
EIH occurs 5 and 45 min after exercise regardless of the intensity used at the joints and sternum which might be explained by local pain-inhibiting pathways and probably to a limited degree by central mechanisms, as no hypoalgesia was observed at the forehead and no changes in CPM occurred.
Topics: Adult; Anaerobic Threshold; Cross-Over Studies; Humans; Male; Pain; Pain Measurement; Pain Perception; Pain Threshold; Young Adult
PubMed: 35809091
DOI: 10.1007/s00421-022-04997-1 -
Osteoarthritis and Cartilage Jul 2015Emerging evidence suggests that pain sensitization plays an important role in pain associated with knee osteoarthritis (OA). This systematic review and meta-analysis... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
Emerging evidence suggests that pain sensitization plays an important role in pain associated with knee osteoarthritis (OA). This systematic review and meta-analysis examined the evidence for pain sensitization in people with knee OA and the relationship between pain sensitization and symptom severity.
METHODS
A search of electronic databases and reference lists was carried out. All full text observational studies published between 2000 and 2014 with the aim of investigating pain sensitization in humans with knee OA using quantitative sensory testing (QST) measures of hyperalgesia and central hyperexcitability were eligible for inclusion. Meta-analysis of data was carried out using a random effects model, which included results comparing knee OA participants to controls, and results comparing high symptom severity to low symptom severity.
RESULTS
Fifteen studies were identified following screening and quality appraisal. For the meta-analysis, pressure pain threshold (PPT) and heat pain threshold (HPT) means and standard deviations were pooled using random effects models. The point estimate was large for differences in PPTs between knee OA participants and controls [-0.85; confidence interval (CI): -1.1 to -0.6], and moderate for PPT differences between knee OA participants with high symptom severity vs those with low symptom severity (0.51; CI: -0.73 to -0.30). A small point estimate was found for differences in HPTs between knee OA participants and controls (-0.42; CI: -0.87 to 0.02).
CONCLUSION
Evidence from this systematic review and meta-analysis suggests that pain sensitization is present in people with knee OA and may be associated with knee OA symptom severity.
Topics: Humans; Hyperalgesia; Osteoarthritis, Knee; Pain; Pain Measurement; Pain Threshold
PubMed: 25749012
DOI: 10.1016/j.joca.2015.02.163 -
European Journal of Pain (London,... Nov 2022Deficient endogenous pain modulation and increased nociceptive excitability are key features of central sensitization and can be assessed in humans by conditioned pain...
BACKGROUND
Deficient endogenous pain modulation and increased nociceptive excitability are key features of central sensitization and can be assessed in humans by conditioned pain modulation (CPM, anti-nociceptive) and temporal summation of pain (TSP, pro-nociceptive), respectively. This study aimed to investigate these measures as proxies for central sensitization in subjects with chronic neuropathic pain (NP) after spinal cord injury (SCI).
METHODS
In paraplegic subjects with NP (SCI-NP; n = 17) and healthy controls (HC; n = 17), parallel and sequential sham-controlled CPM paradigms were performed using pressure pain threshold at the hand, that is, above lesion level, as test stimulus. The conditioning stimulus was a noxious cold (verum) or lukewarm water bath (sham) applied contralaterally. Regarding pro-nociceptive mechanisms, a TSP protocol with individually-adjusted pressure pain stimuli at the thenar eminence was used. CPM and TSP magnitudes were related to intensity and spatial extent of spontaneous NP.
RESULTS
Neither the parallel nor sequential sham-controlled CPM paradigm showed any significant inhibition of above-level pressure pain thresholds for SCI-NP or HC. Accordingly, no group difference in CPM capacity was found, however, subjects with more intense spontaneous NP showed lower inhibitory CPM capacity. TSP was observed for both groups but was not enhanced in SCI-NP.
CONCLUSIONS
Our results do not support altered above-level anti- or pro-nociceptive mechanisms in SCI-NP compared with HC; however, they also highlight the relevance of spontaneous NP intensity with regards to the capacity of endogenous pain modulation in SCI subjects.
SIGNIFICANCE
Central sensitization encompasses deficient endogenous pain modulation and increased nociceptive excitability. These two mechanisms can be assessed in humans by conditioned pain modulation and temporal summation of pain, respectively. Our data demonstrates a lack of descending pain inhibition only in subjects with severe neuropathic pain which may hint towards central sensitization at spinal and/or supra-spinal levels. Disentangling the mechanisms of endogenous pain modulation and neuronal hyperexcitability might improve mechanism-based treatment of neuropathic pain in subjects with spinal cord injury.
Topics: Humans; Neuralgia; Pain Measurement; Pain Threshold; Spinal Cord Injuries
PubMed: 36000307
DOI: 10.1002/ejp.2029 -
Brazilian Journal of Physical Therapy 2023Dry needling is frequently used for the treatment of neck pain but knowledge about its neurophysiological central effects is scarce. (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Dry needling is frequently used for the treatment of neck pain but knowledge about its neurophysiological central effects is scarce.
OBJECTIVES
To compare the immediate effects of a single session of dry needling (DN) and sham needling (SN) on local and distant pressure pain thresholds and conditioned pain modulation in patients with chronic idiopathic neck pain.
METHOD
Participants with chronic idiopathic neck pain were randomly allocated to a DN or SN group. The primary outcome measure was the pressure pain threshold (PPT) at one peripheral location: quadriceps muscle (Q). Secondary outcome measures were local PPTs at the treated (most painful) (tUT) and non-treated upper trapezius muscle (ntUT), absolute and relative conditioned pain modulation (CPM) effects and pain during hot water immersion. Patients were assessed at baseline and immediately post intervention. Linear mixed models were used to examine interaction effects as well as between- and within-group differences.
RESULTS
Fifty-four participants were included for statistical analysis. Linear mixed model analyses showed no significant "group X time" interaction effects for any of the outcome measures. The relative CPM effect at the Q was significantly higher post-intervention, compared to baseline within the DN group (mean difference= 13.52%; 95% CI: 0.46, 26.59).
CONCLUSION
The present study shows no superior effect of DN, compared to SN, in the immediate effect on local and distant PPTs and CPM in patients with chronic idiopathic neck pain.
Topics: Humans; Pain Threshold; Neck Pain; Dry Needling; Trigger Points; Chronic Pain
PubMed: 36709694
DOI: 10.1016/j.bjpt.2023.100481