Pain-related cerebral activation is altered by a distracting cognitive task

Top-down attention does not modulate mechanical hypersensitivity consecutive to central sensitization: insights from an experimental analysis

ABSTRACT

According to the neurocognitive model of attention to pain, when the attentional resources invested in a task unrelated to pain are high, limited cognitive resources can be directed toward the pain. This is supported by experimental studies showing that diverting people's attention away from acute pain leads to experiencing less pain. Theoretical work has suggested that this phenomenon may present a top-down modulatory mechanism for persistent pain as well. However, conclusive empirical evidence is lacking. To fill this gap, we used a preregistered, double-blind, between-subject study design to investigate whether performing a tailored, demanding, and engaging working memory task unrelated to pain (difficult) vs a task that requires less mental effort to be performed (easy), could lead to lower development of secondary hypersensitivity-a hallmark of central sensitization. Eighty-five healthy volunteers, randomly assigned to one of the 2 conditions, performed a visual task with a different cognitive load (difficult vs easy), while secondary hypersensitivity was induced on their nondominant forearm using high-frequency stimulation. To assess the development of secondary hypersensitivity, sensitivity to mechanical stimuli was measured 3 times: T0, for baseline and 20 (T1) and 40 (T2) minutes after the procedure. We did not observe any significant difference in the development of secondary hypersensitivity between the 2 groups, neither in terms of the intensity of mechanical sensitivity nor its spatial extent. Our results suggest that a top-down modulation through attention might not be sufficient to affect pain sensitization and the development of secondary hypersensitivity.

Temporal summation of second pain is affected by cognitive load

This work attempted to clarify the interaction of cognition and pain sensitization during a paradigm of Temporal Summation of Second Pain (TSSP). We analyzed pain ratings and electroencephalographic (EEG) activity obtained from 21 healthy participants during the presentation of four experimental conditions that differed in the manipulation of attention to painful stimuli or working memory load (Attention to hand & TSSP; 0-back & TSSP (low cognitive load); 2-back & TSSP (high cognitive load); 2-back (without pain)). We found that the TSSP was reduced when the attention was diverted and the cognitive load increased, and this reduction was accompanied by higher midfrontal theta activity and lower posterior alpha and central beta activity. Although it is well established that TSSP is a phenomenon that occurs at the spinal level, here we show that it is also affected by supraspinal attentional mechanisms. Delivery of painful repeated stimuli did not affect the performance of the 2-back task but was associated with smaller amplitudes of attentional event-related potentials (ERPs) after standard stimuli (not the target). The study of brain activity during TSSP allowed to clarify the role of top-down attentional modulation in pain sensitization processes. Results contribute to a better understanding of cognitive dysfunction in pain conditions and reinforce the use of therapeutic strategies based on distracting attention away from pain.

Let Kids Play: Using Virtual Reality as a Substitute for General Anesthesia for Minor Procedures in Pediatric Population

BACKGROUND

In the pediatric population, virtual reality (VR) has been used as an adjunct to augment analgesia and reduce the need for opioids. In this study, we review our experience using VR in lieu of anesthesia or sedation to enable minor procedures in children.

METHODS

A retrospective chart review study was performed on patients who presented to our institution from 2019 to 2022 for hormone implant placement, exchange, or removal with VR distraction. Demographic and procedure information was recorded. The primary outcome was successful procedure completion without requiring pharmacologic sedation or analgesia.

RESULTS

A total of 111 patients underwent the following minor procedures with VR and without anesthesia or sedation. Fourteen patients had multiple encounters resulting in a total of 126 encounters. The median age was 11 [6] years. 43 patients were female, 23 were female to male, 6 were non-binary, 7 were male, and 32 were male to female. 58 % had private insurance. Most common diagnosis was precocious puberty (54 %) followed by gender dysphoria (46 %). Most common procedure was implant placement (72 %). 69 % of procedures were performed in the clinic and 31 % in the OR. All procedures were completed without requiring the administration of additional sedation or anesthesia. None of the patients required intravenous catheter placement for the procedure. No intra-procedural complications were recorded.

CONCLUSION

VR is a feasible option that can spare children from sedation or general anesthesia for minor procedures. VR may enable minor procedures in children to be successfully performed in clinic setting.

LEVEL OF EVIDENCE: 4

Effect of Mirror Therapy on Post-Needling Pain Following Deep Dry Needling of Myofascial Trigger Point in Lateral Elbow Pain: Prospective Controlled Pilot Trial

Background: This prospective randomized, controlled pilot trial to explore the immediate effect of adding Mirror Visual Feedback Therapy on pain sensitivity and motor performance among subjects suffering from post-needling pain diagnosed as Lateral Elbow Pain. Methods: A total of 49 participants (23 female, 26 male) were enrolled and randomly allocated to either the experimental group, which received Deep Dry Needling in the m. Brachioradialis, Ischemic Compression, Cold Spray, Stretching, and Mirror Visual Feedback Therapy (n = 25), or a control group without Mirror Visual Feedback Therapy (n = 24). Pre- and post-treatment evaluations included assessments of post-needling pain intensity, pressure pain threshold, two-point discrimination threshold, and maximum hand grip strength. Results: Intergroup analysis revealed a statistically significant reduction in post-needling pain intensity favoring the experimental group (U = 188.00, p = 0.034). Additionally, intragroup analysis showed significant improvements in post-needling pain intensity (MD = 0.400, SEM = 0.271, W = 137.00, p = 0.047) and pressure pain threshold (MD = 0.148 Kg/cm2, SEM = 0.038, W = 262.00, p < 0.001) within the experimental group following the intervention. Conclusions: These findings suggest a potential benefit of integrating Mirror Visual Feedback Therapy into treatment protocols for individuals with Lateral Elbow Pain experiencing post-needling discomfort. Further research is necessary to fully elucidate the clinical implications of these findings.

No Evidence That Working Memory Modulates the Plasticity of the Nociceptive System, as Measured by Secondary Mechanical Hypersensitivity

The effect of cognition on the plasticity of the nociceptive system remains controversial. In this study, we examined whether working memory can buffer against the development of secondary hypersensitivity. Thirty-five healthy women participated in 3 experimental conditions. In each condition, they underwent electrical stimulation of the skin for 2 minutes (middle-frequency electrical stimulation [MFS]), which induces secondary hypersensitivity. During MFS, participants executed either an individually tailored and rewarded n-back task (working memory condition), a rewarded reaction-time task (non-working memory condition), or no task at all (control condition). Before and after MFS, participants rated the self-reported intensity and unpleasantness of mechanical pinprick stimuli. Fear of MFS was also assessed. Heart rate variability was measured to examine potential differences between the 3 conditions and steady-state evoked potentials to the electrical stimulation were recorded to investigate differences in cortical responses. We report no significant difference in hypersensitivity between the 3 conditions. Moreover, engaging in the cognitive tasks did not affect the heart rate variability or the steady-state evoked potentials. Interestingly, higher fear of MFS predicted greater hypersensitivity. In conclusion, we found no evidence that working memory affects the plasticity of the nociceptive system, yet pain-related fear plays a role. PERSPECTIVE: This study shows that the execution of a cognitive task, irrespective of cognitive load or working memory, does not significantly modulate the development of secondary hypersensitivity, heart rate variability, or steady-state evoked potentials. However, higher pain-related fear seems to contribute to greater hypersensitivity.

Total-Body Perfusion Imaging with [11C]-Butanol

Tissue perfusion can be affected by physiology or disease. With the advent of total-body PET, quantitative measurement of perfusion across the entire body is possible. [11C]-butanol is a perfusion tracer with a superior extraction fraction compared with [15O]-water and [13N]-ammonia. To develop the methodology for total-body perfusion imaging, a pilot study using [11C]-butanol on the uEXPLORER total-body PET/CT scanner was conducted. Methods: Eight participants (6 healthy volunteers and 2 patients with peripheral vascular disease [PVD]) were injected with a bolus of [11C]-butanol and underwent 30-min dynamic acquisitions. Three healthy volunteers underwent repeat studies at rest (baseline) to assess test-retest reproducibility; 1 volunteer underwent paired rest and cold pressor test (CPT) studies. Changes in perfusion were measured in the paired rest-CPT study. For PVD patients, local changes in perfusion were investigated and correlated with patient medical history. Regional and parametric kinetic analysis methods were developed using a 1-tissue compartment model and leading-edge delay correction. Results: Estimated baseline perfusion values ranged from 0.02 to 1.95 mL·min-1·cm-3 across organs. Test-retest analysis showed that repeat baseline perfusion measurements were highly correlated (slope, 0.99; Pearson r = 0.96, P < 0.001). For the CPT subject, the largest regional increases were in skeletal muscle (psoas, 142%) and the myocardium (64%). One of the PVD patients showed increased collateral vessel growth in the calf because of a peripheral stenosis. Comorbidities including myocardial infarction, hypothyroidism, and renal failure were correlated with variations in organ-specific perfusion. Conclusion: This pilot study demonstrates the ability to obtain reproducible measurements of total-body perfusion using [11C]-butanol. The methods are sensitive to local perturbations in flow because of physiologic stressors and disease.

Development of Immersive Virtual Reality-Based Hand Rehabilitation System Using a Gesture-Controlled Rhythm Game With Vibrotactile Feedback: An fNIRS Pilot Study

Recently, virtua reality (VR) has been widely utilized with rehabilitation to promote user engagement, which has been shown to induce brain plasticity. In this study, we developed a VR-based hand rehabilitation system consisting of a personalized gesture-controlled rhythm game with vibrotactile feedback and investigated the cortical activation pattern induced by our system using functional near-infrared spectroscopy (fNIRS). Our system provides vibrotactile feedback as the user matches their hand gestures to VR targets customized to their pre-recorded hand gestures. Cortical activation was measured via fNIRS during 420 seconds of alternating gameplay and rest in 11 healthy subjects and one stroke survivor. Regions of interest (ROI) were the prefrontal cortex (PFC), the premotor cortex & the supplementary motor area (PMC&SMA), the primary sensorimotor cortex (SM1), and the somatosensory association cortex (SAC). The mean success rate of gesture matching among healthy subjects was 90 % with a standard deviation of 10.7 %, and the success rate of the stroke survivor was 79.6 %. The averaged cortical activation map for the 11 healthy subjects and the individual cortical activation map for the single stroke survivor showed increased hemodynamic responses of oxygenated hemoglobin (HbO) during the VR-based hand rehabilitation compared to the resting condition. Paired t-test analysis demonstrated a significant increase in HbO activation values in 19 out of 51 channels, corresponding to all ROIs except the left PFC and PMC&SMA, which exhibited high subject variability. The experimental results indicate that the proposed system successfully activated brain areas related to motor planning/execution, multisensory integration, and attention.

The role of the male rat infralimbic cortex in distraction analgesia

Cognitive interventions, including distraction, have been successfully utilized in the manipulation of experimental pain and the treatment of clinical pain. Attentional diversions can reduce the experience of pain, a phenomenon known as distraction analgesia (DA). Prior research has suggested that variations in stimulus intensity may influence the magnitude of DA. However, the neural substrates of DA remain largely unknown. Converging evidence suggests that the infralimbic cortex (IL) in the brains of rats may contribute to the phenomenon of DA. The function of the rat IL in DA has never been directly investigated, therefore, this study sought to identify the role of the IL at two levels of noxious stimulus intensity among brain-intact and IL lesioned male rats within an established rat model of DA. A distractor object reduced formalin-induced nociceptive behavior in brain-intact rats, and this DA effect was detectable during low- (0.5% formalin) and high-intensity (1% formalin) stimulation. IL lesion resulted in a near-complete elimination of the DA effect and an overall reduction in formalin pain. These results provide the first known evidence that (i) the IL is involved in processing DA in rats, (ii) the IL contributes to formalin-induced nociceptive behavior irrespective of distraction, and (iii) a high-intensity stimulation was generally more susceptible to DA than low-intensity stimulation. These findings may further inform the mechanisms and future development of non-pharmacological strategies to reduce pain.

Exploring the independent association of employment status to cancer survivors' health-related quality of life

BACKGROUND

Having a job has been associated with better Health-Related Quality of Life (HRQOL) in cancer survivors. However, the sociodemographic and disease-related profiles characterizing the survivors being employed and those having better HRQOL largely overlap. The present study aims to discern the degree to which employment status is independently associated with cancer survivors' HRQOL or if it mainly reflects the impact of other sociodemographic and cancer-related variables.

METHODS

Cross-sectional study on a heterogeneous sample of 772 working-age survivors of adult-onset cancer. An instrument specifically designed to assess HRQOL in cancer survivors and Multivariate Variance Analysis (MANOVA) were used.

RESULTS

Survival phase, cancer type, and employment status showed the main effects on cancer survivors' HRQOL. In particular, being employed (vs unemployed) had the greatest positive association with HRQOL, affecting ten of the twelve HRQOL domains considered. Also, interaction effects highlighted the role of age (younger) and marital status (single) as risk factors for a greater negative impact of variables affecting the survivor's HRQOL.

CONCLUSIONS

The application of a multivariate methodology sheds new light on two relevant issues for the cancer survivor's HRQOL: (i) the existence of differences between diagnostic groups that are not attributed to other variables such as sex, and (ii) the important and independent role that employment status plays. Comprehensive cancer survivorship care should focus more on high-risk groups and include having a job as an essential aspect to consider and prompt. The fact that the employment status is susceptible to change represents a valuable opportunity to care for the wellbeing of this population.

Translational aspects of deep brain stimulation for chronic pain

The use of deep brain stimulation (DBS) for the treatment of chronic pain was one of the first applications of this technique in functional neurosurgery. Established brain targets in the clinic include the periaqueductal (PAG)/periventricular gray matter (PVG) and sensory thalamic nuclei. More recently, the anterior cingulum (ACC) and the ventral striatum/anterior limb of the internal capsule (VS/ALIC) have been investigated for the treatment of emotional components of pain. In the clinic, most studies showed a response in 20%-70% of patients. In various applications of DBS, animal models either provided the rationale for the development of clinical trials or were utilized as a tool to study potential mechanisms of stimulation responses. Despite the complex nature of pain and the fact that animal models cannot reliably reflect the subjective nature of this condition, multiple preparations have emerged over the years. Overall, DBS was shown to produce an antinociceptive effect in rodents when delivered to targets known to induce analgesic effects in humans, suggesting a good predictive validity. Compared to the relatively high number of clinical trials in the field, however, the number of animal studies has been somewhat limited. Additional investigation using modern neuroscience techniques could unravel the mechanisms and neurocircuitry involved in the analgesic effects of DBS and help to optimize this therapy.

Can we characterize A-P/IAP behavioural phenotypes in people with chronic pain?

Two behavioural phenotypes in healthy people have been delineated based on their intrinsic attention to pain (IAP) and whether their reaction times (RT) during a cognitively-demanding task are slower (P-type) or faster (A-type) during experimental pain. These behavioural phenotypes were not previously studied in chronic pain populations to avoid using experimental pain in a chronic pain context. Since pain rumination (PR) may serve as a supplement to IAP without needing noxious stimuli, we attempted to delineate A-P/IAP behavioural phenotypes in people with chronic pain and determined if PR can supplement IAP. Behavioural data acquired in 43 healthy controls (HCs) and 43 age-/sex-matched people with chronic pain associated with ankylosing spondylitis (AS) was retrospectively analyzed. A-P behavioural phenotypes were based on RT differences between pain and no-pain trials of a numeric interference task. IAP was quantified based on scores representing reported attention towards or mind-wandering away from experimental pain. PR was quantified using the pain catastrophizing scale, rumination subscale. The variability in RT was higher during no-pain trials in the AS group than HCs but was not significantly different in pain trials. There were no group differences in task RTs in no-pain and pain trials, IAP or PR scores. IAP and PR scores were marginally significantly positively correlated in the AS group. RT differences and variability were not significantly correlated with IAP or PR scores. Thus, we propose that experimental pain in the A-P/IAP protocols can confound testing in chronic pain populations, but that PR could be a supplement to IAP to quantify attention to pain.

The association of spouse interactions and emotional learning in interference related to chronic back pain

Social interactions affect individual behaviours, preferences, and attitudes. This is also critical in the context of experiencing pain and expressing pain behaviours, and may relate to learned emotional responses. In this respect, individual variability in the medial prefrontal cortex (mPFC), which is involved in adjusting an organism's behaviour to its environment by evaluating and interpreting information within the context of past experiences, is important. It is critical for selecting suitable behavioural responses within a social environment and may reinforce maladaptation in chronic pain. In our study, we used brain imaging during appetitive and aversive pavlovian conditioning in persons with chronic back pain (CBP), subacute back pain (SABP), and healthy controls (HC), together with information on spouse responses to pain behaviours. We also examined the relationship of these responses with pain-related interference in the patients. Our findings yielded a significant negative association between mPFC responses to appetitive and aversive learning in CBP. We also observed a significant negative association for mPFC responses during aversive learning and distracting spouse responses, and a significant positive association between mPFC responses during appetitive learning and solicitous spouse responses in CBP. Both significantly predicted pain-related interference in the CBP group (explained variance up to 53%). Significant associations were not found for SABP or HC. Our findings support an association between appetitive and aversive pavlovian learning, related brain circuits and spouse responses to pain in CBP, where appetitive and aversive learning processes seem to be differentially involved. This can inform prevention and early intervention in a mechanistic approach.

Neural mechanisms underlying the conditioned pain modulation response: a narrative review of neuroimaging studies

ABSTRACT

Processing spatially distributed nociceptive information is critical for survival. The conditioned pain modulation (CPM) response has become a common psychophysical test to examine pain modulation capabilities related to spatial filtering of nociceptive information. Neuroimaging studies have been conducted to elucidate the neural mechanisms underlying the CPM response in health and chronic pain states, yet their findings have not been critically reviewed and synthesized before. This narrative review presents a simplified overview of MRI methodology in relation to CPM assessments and summarizes the findings of neuroimaging studies on the CPM response. The summary includes functional MRI studies assessing CPM responses during scanning as well as functional and structural MRI studies correlating indices with CPM responses assessed outside of the scanner. The findings are discussed in relation to the suggested mechanisms for the CPM response. A better understanding of neural mechanisms underlying spatial processing of nociceptive information could advance both pain research and clinical use of the CPM response as a marker or a treatment target.

From nociception to pain perception, possible implications of astrocytes

Astrocytes are determinants for the functioning of the CNS. They respond to neuronal activity with calcium increases and can in turn modulate synaptic transmission, brain plasticity as well as cognitive processes. Astrocytes display sensory-evoked calcium responses in different brain structures related to the discriminative system of most sensory modalities. In particular, noxious stimulation evoked calcium responses in astrocytes in the spinal cord, the hippocampus, and the somatosensory cortex. However, it is not clear if astrocytes are involved in pain. Pain is a private, personal, and complex experience that warns us about potential tissue damage. It is a perception that is not linearly associated with the amount of tissue damage or nociception; instead, it is constructed with sensory, cognitive, and affective components and depends on our previous experiences. However, it is not fully understood how pain is created from nociception. In this perspective article, we provide an overview of the mechanisms and neuronal networks that underlie the perception of pain. Then we proposed that coherent activity of astrocytes in the spinal cord and pain-related brain areas could be important in binding sensory, affective, and cognitive information on a slower time scale.

Training intervention effects on cognitive performance and neuronal plasticity—A pilot study

Studies suggest that people suffering from chronic pain may have altered brain plasticity, along with altered functional connectivity between pain-processing brain regions. These may be related to decreased mood and cognitive performance. There is some debate as to whether physical activity combined with behavioral therapy (e.g. cognitive distraction, body scan) may counteract these changes. However, underlying neuronal mechanisms are unclear. The aim of the current pilot study with a 3-armed randomized controlled trial design was to examine the effects of sensorimotor training for nonspecific chronic low back pain on (1) cognitive performance; (2) fMRI activity co-fluctuations (functional connectivity) between pain-related brain regions; and (3) the relationship between functional connectivity and subjective variables (pain and depression). Six hundred and sixty two volunteers with non-specific chronic low back pain were randomly allocated to a unimodal (sensorimotor training), multidisciplinary (sensorimotor training and behavioral therapy) intervention, or to a control group within a multicenter study. A subsample of patients (n = 21) from one study center participated in the pilot study presented here. Measurements were at baseline, during (3 weeks, M2) and after intervention (12 weeks, M4 and 24 weeks, M5). Cognitive performance was measured by the Trail Making Test and functional connectivity by MRI. Pain perception and depression were assessed by the Von Korff questionnaire and the Hospital and Anxiety. Group differences were calculated by univariate and repeated ANOVA measures and Bayesian statistics; correlations by Pearson's r. Change and correlation of functional connection were analyzed within a pooled intervention group (uni-, multidisciplinary group). Results revealed that participants with increased pain intensity at baseline showed higher functional connectivity between pain-related brain areas used as ROIs in this study. Though small sample sizes limit generalization, cognitive performance increased in the multimodal group. Increased functional connectivity was observed in participants with increased pain ratings. Pain ratings and connectivity in pain-related brain regions decreased after the intervention. The results provide preliminary indication that intervention effects can potentially be achieved on the cognitive and neuronal level. The intervention may be suitable for therapy and prevention of non-specific chronic low back pain.

Better Executive Functions Are Associated With More Efficient Cognitive Pain Modulation in Older Adults: An fMRI Study

Growing evidence suggests that aging is associated with less efficient endogenous pain modulation as demonstrated by reduced conditioned pain modulation, and that these changes may be mediated by differences in frontal functioning. Yet, little is known about potential age-related changes in cognitive pain modulation, such as distraction from pain. In a first session, 30 healthy young (19-35 years) and 30 healthy older (59-82 years) adults completed a battery of neuropsychological tests. In a second session, we acquired functional brain images while participants completed a working memory task with two levels of cognitive load (high vs. low) and concurrently received individually adjusted heat stimuli (warm vs. painful). In both age groups, completing the high load task was associated with a significant reduction in the perceived intensity and unpleasantness of painful stimuli and a reduction in activation of brain regions involved in pain processing. Group comparisons revealed that young adults showed a stronger de-activation of brain regions involved in pain processing during the high load vs. the low load task, such as the right insula, right mid cingulate cortex and left supramarginal gyrus, compared to older adults. Older adults, on the other hand, showed an increased activation in the anterior cingulate cortex during the high load vs. low load task, when compared to young adults. Covariate analyses indicated that executive functions significantly predicted neural pain modulation in older adults: Better executive functions were associated with a more pronounced de-activation of the insula, thalamus and primary somatosensory cortex and increased activation of prefrontal regions during the high vs. low load task. These findings suggest that cognitive pain modulation is altered in older age and that the preservation of executive functions may have beneficial effects on the efficacy of distraction from pain.

Role of anterior cingulate cortex inputs to periaqueductal gray for pain avoidance

Although pain-related excessive fear is known to be a key factor in chronic pain disability, which involves the anterior cingulate cortex (ACC), little is known about the downstream circuits of the ACC for fear avoidance in pain processing. Using behavioral experiments and functional magnetic resonance imaging with optogenetics at 15.2 T, we demonstrate that the ACC is a part of the abnormal circuit changes in chronic pain and its downstream circuits are closely related to modulating sensorimotor integration and generating active movement rather than carrying sensory information. The projection from the ACC to the dorsolateral and lateral parts of the periaqueductal gray (dl/lPAG) especially enhances both reflexive and active avoidance behavior toward pain. Collectively, our results indicate that increased signals from the ACC to the dl/lPAG might be critical for excessive fear avoidance in chronic pain disability.

The interaction between pain and cognition: on the roles of task complexity and pain intensity

OBJECTIVES

The interaction between pain and cognition includes a concurrent negative effect of pain on cognitive performance and an analgesic effect of cognitive distraction on pain experience. The purpose of this exploratory study was to investigate the role of pain intensity and task complexity on this interaction.

METHODS

Two experiments were conducted in healthy volunteers. In both experiments, participants completed 3 conditions: a pain only condition (consisting of the cold pressor test), a cognition only condition (consisting of the cognitive task) and a combined condition (concurrent administration of the cold pressor and cognitive task). In experiment I, participants performed one out of three possible tasks that differed in cognitive load (low, medium, high). In experiment II the parameters of the pain stimulus, induced by a cold pressor test, were adapted and only the high load cognitive task was employed. Pain scores, reaction times, and accuracy rates were recorded.

RESULTS

In experiment I, cognitive distraction significantly decreased pain scores, irrespective of the cognitive load of the task. Pain did not affect cognitive performance. In experiment II, pain diminished accuracy rates. No effect of cognitive distraction on pain was observed. Individual characteristics did not noticeably influence the interaction between pain and cognition.

CONCLUSIONS

The results of this study suggest a two-way interaction, however no evidence for a simultaneous bidirectional relationship was found. Cognitive distraction successfully reduces pain, up until a certain point where this relationship is reversed, and pain starts to interfere with cognitive performance. This may imply that priorities shift at a certain pain-threshold, however further research should confirm this hypothesis. This study could contribute to further understanding of cognitive mechanisms related to pain perception.

Virtual Reality Therapy in Palliative Care: A Case Series

OBJECTIVES

Virtual reality (VR) opens a variety of therapeutic options to improve symptom burden in patients with advanced disease. Until to date, only few studies have evaluated the use of VR therapy in the context of palliative care. This case series aims to evaluate the feasibility and acceptability of VR therapy in a population of palliative care patients.

METHODS

In this single-site case series, we report on six palliative care patients undergoing VR therapy. The VR therapy consisted of a one-time session ranging between 20 to 60 minutes depending on the patient's needs and the content chosen for the VR sessions. A semi-structured survey was conducted and the Edmonton Symptom Assessment System (ESAS) and the Distress Thermometer were performed pre- and post-intervention.

RESULTS

Overall, VR therapy was well accepted by all patients. Five out of six patients reported having appreciated VR therapy. There were individual differences of perceived effects using VR therapy. The semi-structured survey revealed that some patients felt a temporary detachment from their body and that patients were able to experience the VR session as a break from omnipresent worries and the hospital environment ("I completely forgot where I am"). There was a considerable reduction in the total ESAS score post-treatment (T0 ESASTot = 27.2; T1 ESASTot = 18.8) and a slightly reduction in distress (T0 DTTot = 4.4; T1 DTTot = 3.8). However, two patients were more tired after the intervention.Significance of Results: Our preliminary results demonstrate that VR therapy is acceptable, feasible and safe for use within a palliative care population and appears to be a viable treatment option. Clinical trials are both warranted and necessary to confirm any therapeutic effects of VR therapy, as is the need to tailor VR systems better for use in palliative care settings.

Structural and Functional Abnormalities in Knee Osteoarthritis Pain Revealed With Multimodal Magnetic Resonance Imaging

The knee osteoarthritis (KOA) pain is the most common form of arthritis pain affecting millions of people worldwide. Long-term KOA pain causes motor impairment and affects affective and cognitive functions. However, little is known about the structural and functional abnormalities induced by long-term KOA pain. In this work, high-resolution structural magnetic resonance imaging (sMRI) and resting-state functional MRI (rs-fMRI) data were acquired in patients with KOA and age-, sex-matched healthy controls (HC). Gray matter volume (GMV) and fractional amplitude of low-frequency fluctuation (fALFF) were used to study the structural and functional abnormalities in patients with KOA. Compared with HC, patients with KOA showed reduced GMV in bilateral insula and bilateral hippocampus, and reduced fALFF in left cerebellum, precentral gyrus, and the right superior occipital gyrus. Patients with KOA also showed increased fALFF in left insula and bilateral hippocampus. In addition, the abnormal GMV in left insula and fALFF in left fusiform were closely correlated with the pain severity or disease duration. These results indicated that long KOA pain leads to brain structural and functional impairments in motor, visual, cognitive, and affective functions that related to brain areas. Our findings may facilitate to understand the neural basis of KOA pain and the future therapy to relieve disease symptoms.

Effective connectivity of brain networks controlling human thermoregulation

Homeostatic centers in the mammalian brainstem are critical in responding to thermal challenges. These centers play a prominent role in human thermoregulation, but humans also respond to thermal challenges through behavior modification. Behavioral modifications are presumably sub served by interactions between the brainstem and interoceptive, cognitive and affective elements in human brain networks. Prior evidence suggests that interoceptive regions such as the insula, and cognitive/affective regions such as the orbitofrontal cortex and anterior cingulate cortex are crucial. Here we used dynamic causal modeling (DCM) to discover likely generative network architectures and estimate changes in the effective connectivity between nodes in a hierarchically organized thermoregulatory network (homeostatic-interoceptive-cognitive/affective). fMRI data were acquired while participants (N = 20) were subjected to a controlled whole body thermal challenge that alternatingly evoked sympathetic and parasympathetic responses. Using a competitive modeling framework (ten competing modeling architectures), we demonstrated that sympathetic responses (evoked by whole-body cooling) resulted in more complex network interactions along two ascending pathways: (i) homeostatic interoceptive and (ii) homeostatic cognitive/affective. Analyses of estimated connectivity coefficients demonstrated that sympathetic responses evoked greater network connectivity in key pathways compared to parasympathetic responses. These results reveal putative mechanisms by which human thermoregulatory networks evince a high degree of contextual sensitivity to thermoregulatory challenges. The patterns of the discovered interactions also reveal how information propagation from homeostatic regions to both interoceptive and cognitive/affective regions sub serves the behavioral repertoire that is an important aspect of thermoregulatory defense in humans.

Small surgeries, big smiles: using virtual reality to reduce the need for sedation or general anesthesia during minor surgical procedures

PURPOSE

Children often require anesthesia for simple diagnostic and therapeutic procedures. The aim of this study was to evaluate the feasibility of using virtual reality (VR) to reduce sedation in children undergoing minor surgical procedures.

METHOD

In this prospective, non-randomized clinical trial, pediatric patients at a free-standing children's hospital undergoing hormone implant placement, removal, or exchange were recruited to use VR and local anesthesia instead of procedural sedation or general anesthesia (GA). Patients were enrolled between November 2017 and March 2020, and were compared to historic controls who underwent similar procedures without VR between April 2016 and February 2020. Primary outcome measure was successful procedure completion without sedation or GA. Secondary measures included assessments of pain, fear and anxiety, patient compliance, procedural and recovery times.

RESULTS

Twenty-eight patients underwent 29 procedures with VR. Hormone implants (72%), removals (7%), or exchanges (21%) were completed without GA, sedation or IV placement. Procedure lengths and pain scores were similar between VR patients and historic controls, but recovery times were significantly shorter in VR patients (18 vs 65 min, p < 0.001). Participant satisfaction scores were high, with 95% recommending VR to others.

CONCLUSIONS

VR is a feasible alternative to sedation or GA for select pediatric patients undergoing minor surgical procedures.

A Personalized Spatial-Temporal Cold Pain Intensity Estimation Model Based on Facial Expression

OBJECTIVE

Pain assessment is of great importance in both clinical research and patient care. Facial expression analysis is becoming a key part of pain detection because it is convenient, automatic, and real-time. The aim of this study is to present a cold pain intensity estimation experiment, investigate the importance of the spatial-temporal information on facial expression based cold pain, and study the performance of the personalized model as well as the generalized model.

METHODS

A cold pain experiment was carried out and facial expressions from 29 subjects were extracted. Three different architectures (Inception V3, VGG-LSTM, and Convolutional LSTM) were used to estimate three intensities of cold pain: No pain, Moderate pain, and Severe Pain. Architectures with Sequential information were compared with single-frame architecture, showing the importance of spatial-temporal information on pain estimation. The performances of the personalized model and the generalized model were also compared.

RESULTS

A mean F1 score of 79.48% was achieved using Convolutional LSTM based on the personalized model.

CONCLUSION

This study demonstrates the potential for the estimation of cold pain intensity from facial expression analysis and shows that the personalized spatial-temporal framework has better performance in cold pain intensity estimation.

SIGNIFICANCE

This cold pain intensity estimator could allow convenient, automatic, and real-time use to provide continuous objective pain intensity estimations of subjects and patients.

Neural mechanisms of pain relief through paying attention to painful stimuli

ABSTRACT

A commonly held belief suggests that turning one's attention away from pain reduces it, while paying attention to pain increases it. However, some attention-based therapeutic strategies for pain, such as mindfulness-based interventions, suggest that paying attention to painful stimuli can reduce pain, resulting in seemingly contradictory conclusions regarding attention and pain. Here, we investigated the analgesic effects of attention modulation, and provide behavioral and neural evidence that paying attention to pain can reduce it when attention is directed toward the specific features of painful stimuli. The analgesic effects of paying attention to painful stimuli were mediated by the primary somatosensory cortex via goal-directed attention regions in the prefrontal and parietal cortex. These findings suggest that suppressing early somatosensory processing through top-down modulation is the key mechanism of the analgesic effects of paying attention to painful stimuli, providing evidence that pain itself can be used as a component of pain management.

Pain processing in older adults with dementia-related cognitive impairment is associated with frontal neurodegeneration

Experimental pain research has shown that pain processing seems to be heightened in dementia. It is unclear which neuropathological changes underlie these alterations. This study examined whether differences in pressure pain sensitivity and endogenous pain inhibition (conditioned pain modulation (CPM)) between individuals with a dementia-related cognitive impairment (N=23) and healthy controls (N=35) are linked to dementia-related neurodegeneration. Pain was assessed via self-report ratings and by analyzing the facial expression of pain using the Facial Action Coding System. We found that cognitively impaired individuals show decreased CPM inhibition as assessed by facial responses compared to healthy controls, which was mediated by decreased gray matter volume in the medial orbitofrontal and anterior cingulate cortex in the patient group. This study confirms previous findings of intensified pain processing in dementia when pain is assessed using non-verbal responses. Our findings suggest that a loss of pain inhibitory functioning caused by structural changes in prefrontal areas might be one of the underlying mechanisms responsible for amplified pain responses in individuals with a dementia-related cognitive impairment.

Cognition and Pain: A Review

Cognition is defined as the brain's ability to acquire, process, store, and retrieve information. Pain has been described as an unpleasant sensory or emotional experience, and for experiencing pain consciously, cognitive processing becomes imperative. Moreover, evaluation of pain strongly depends on cognition as it requires learning and recall of previous experiences. There could be a possible close link between neural systems involved in cognition and pain processing, and studies have reported an association between pain and cognitive impairment. In this narrative review, we explore the available evidence that has investigated cognitive changes associated with pain. We also examine the anatomical, biochemical, and molecular association of pain and neuro-cognition. Additionally, we focus on the cognitive impairment caused by analgesic medications. There is a need to improve our understanding of pathophysiology and cognitive impairment mechanisms associated with chronic pain and its treatment. This area provides a diverse opportunity for grounding future research, aiding institution of timely interventions to prevent chronic pain and associated cognitive decline, ultimately improving patient care.

"Doc McStuffins: Doctor for a Day" Virtual Reality (DocVR) for Pediatric Preoperative Anxiety and Satisfaction: Pediatric Medical Technology Feasibility Study

Background

Preoperative anxiety is a common occurrence among children and is associated with a host of maladaptive postoperative behaviors. Consequently, increased attention has been placed on interventions to reduce preoperative anxiety and its associated outcomes. Child Life preparation prior to surgery includes evidence-based practices such as age-appropriate distraction and therapeutic play. Virtual reality (VR) is a promising addition to the Child Life toolbox to address anxiety prior to surgery. The current study evaluates the implementation and feasibility of a VR experience, “Doc McStuffins: Doctor for a Day Virtual Reality Experience” (DocVR), developed by Disney Junior in collaboration with Children’s Hospital Los Angeles, to target pediatric preoperative anxiety.

Objective

The primary aim of this study was to examine the feasibility and efficacy of DocVR for preoperative anxiety. A secondary aim was to improve patient, caregiver, and health care provider satisfaction with the preoperative experience.

Methods

In this study, 51 patients (age 6-14 years) scheduled for surgery in the ambulatory surgery center and the main operating room at Children’s Hospital Los Angeles were approached to participate in Disney’s DocVR experience. The patients played the DocVR experience for an average of 18 minutes (3-55 minutes). Irrespective of surgical procedure, patients and their families were eligible, as long as they had no known marked cognitive or visual impairments that would interfere with completing the survey and engaging in the DocVR experience.

Results

Patients who tried the DocVR experience (n=51) responded overwhelmingly positively to both the VR technology and to the game itself. Patients experienced a statistically significant decrease in anxiety following DocVR game play (Z=–3.26, P=.001). On the Facial Affective Scale, the percentage of patients who chose the face with the most positive facial expression to represent their affect increased from 23% (12/51) pre-VR to 49% (25/47) post-VR. Furthermore, 97% (38/39) of patients reported feeling more comfortable at the hospital, and 74% (28/38) reported feeling less scared at the hospital after playing the game. The game was enjoyed by 94% (46/49) of patients, and 88% (30/34) of patients reported feeling both “Interested” and “Involved” in the game.

Conclusions

DocVR is a feasible and beneficial VR experience to relieve pediatric preoperative anxiety and improve satisfaction in the preoperative area. The VR experience resulted in a decrease in overall anxiety and an increase in overall positive affect during the preoperative time. Patients also responded positively to the game, confirming their interest in the content and affirming the quality of the DocVR experience. The positive response to the game indicates that DocVR has the potential to make the overall preoperative experience less anxiety-producing and more comfortable, which leads to improved patient satisfaction. Naturally, improved patient outcomes lead to improved caregiver and health care provider satisfaction.

Sickness and sleep health predict frustration and affective responses to a frustrating trigger

Fluctuations in health and sleep are common, but we know surprisingly little about how these daily life stressors affect one's level of frustration and sensitivity to becoming frustrated. In this pre-registered study, 517 participants (Mage = 30.4, SD = 10.4) reported their current sickness symptoms, health status, sleepiness, and sleep duration and quality the previous night. They also rated their general frustration and mood before and after a mild frustration-eliciting task. In the task, participants were instructed to copy geometric shapes onto a piece of paper, without lifting the pen from the paper. Participants were given three minutes to copy the eight shapes, but in order to induce frustration half of them were unsolvable. The study was subsequently repeated in an independent sample (N = 113). Frustration increased in response to the task; however, those with the worst sickness symptoms or sleep health reduced or did not change their frustration levels. Instead, across both studies, frustration was already high at baseline for these individuals. These findings indicate that being sick or having poor sleep is related to high general frustration, but resilience to further frustration due to mild frustrating situations.

Painful stimulation increases spontaneous blink rate in healthy subjects

Spontaneous blink rate is considered a biomarker of central dopaminergic activity. Recent evidence suggests that the central dopaminergic system plays a role in nociception. In the present study, we aimed to investigate whether pain modulates spontaneous blink rate in healthy subjects. We enrolled 15 participants. Spontaneous blink rate was quantified with an optoelectronic system before and after: (1) a painful laser stimulation, and (2) an acoustic startling stimulation. In control experiments, we investigated whether laser stimulation effects depended on stimulation intensity and whether laser stimulation induced any changes in the blink reflex recovery cycle. Finally, we investigated any relationship between spontaneous blink rate modification and pain modulation effect during the cold pressor test. Laser, but not acoustic, stimulation increased spontaneous blink rate. This effect was independent of stimulation intensity and negatively correlated with pain perception. No changes in trigeminal-facial reflex circuit excitability were elicited by laser stimulation. The cold pressor test also induced an increased spontaneous blink rate. Our study provides evidence on the role of dopamine in nociception and suggests that dopaminergic activity may be involved in pain modulation. These findings lay the groundwork for further investigations in patients with pathological conditions characterized by dopaminergic deficit and pain.

Parallel cortical-brainstem pathways to attentional analgesia

Pain demands attention, yet pain can be reduced by focusing attention elsewhere. The neural processes involved in this robust psychophysical phenomenon, attentional analgesia, are still being defined. Our previous fMRI study linked activity in the brainstem triad of locus coeruleus (LC), rostral ventromedial medulla (RVM) and periaqueductal grey (PAG) with attentional analgesia. Here we identify and model the functional interactions between these regions and the cortex in healthy human subjects (n = 57), who received painful thermal stimuli whilst simultaneously performing a visual attention task. RVM activity encoded pain intensity while contralateral LC activity correlated with attentional analgesia. Psycho-Physiological Interaction analysis and Dynamic Causal Modelling identified two parallel paths between forebrain and brainstem. These connections are modulated by attentional demand: a bidirectional anterior cingulate cortex (ACC) - right-LC loop, and a top-down influence of task on ACC-PAG-RVM. By recruiting discrete brainstem circuits, the ACC is able to modulate nociceptive input to reduce pain in situations of conflicting attentional demand.

Differential effects of visually induced analgesia and attention depending on the pain stimulation site

BACKGROUND

The term 'visually induced analgesia' describes a reduced pain perception induced by watching the painful body part as opposed to watching a neutral object. In chronic back pain patients, experimental pain, movement-induced pain and habitual pain can be reduced with visual feedback. Visual feedback can also enhance the effects of both massage treatment and manual therapy. The impact of somatosensory attentional processes remains unclear.

METHODS

In the current study, participants received painful electrical stimuli to their thumb and back while being presented with either a real-time video of their thumb or back (factor feedback). In addition, using an oddball paradigm, they had to count the number of deviant stimuli, applied to either their back or thumb (factor attention) and rate the pain intensity.

RESULTS

We found a significant main effect for attention with decreased pain ratings during attention. There was no main effect for visual feedback and no significant interaction between visual feedback and attention. Post-hoc tests revealed that the lowest pain intensity ratings were achieved during visual feedback of the back/ thumb and counting at the back/ thumb.

CONCLUSION

These data suggest that the modulation of perceived acute pain by visually induced analgesia may be influenced by a simultaneous somatosensory attention task.

SIGNIFICANCE

Somatosensory attention reduced experimental pain intensity in the thumb and back in the presence of both congruent and incongruent visual feedback. We found no significant visual feedback effect on the complex interplay between visual feedback and somatosensory attention.

The early influence of COVID-19 pandemic-associated restrictions on pain, mood, and everyday life of patients with painful polyneuropathy

Supplemental Digital Content is Available in the Text.

Validated questionnaires revealed a shift of attention from chronic pain towards the COVID-19 pandemic in patients with chronic painful polyneuropathy.

Introduction:

The SARS-Cov-2 pandemic requires special attention on its psychological effects and the impact on patients with chronic pain.

Objectives:

This study aimed at examining the influence of the COVID-19 pandemic-associated regulations initiated by the German government on pain intensity and characteristics, emotional well-being, and everyday life of patients with painful polyneuropathy.

Methods:

Forty-three patients (well assessed with questionnaires before the pandemic and without change of their health status between baseline and current assessment) were investigated with validated, self-reported questionnaires and COVID-19-specific items 2 weeks after the regulations came into effect.

Results:

Pain intensity remained stable or even improved like the neuropathic pain symptom inventory total score (t0: 33.54 ± 20.48 vs t1: 27.38 ± 16.16, P = 0.008). Only 11.6% reported a pandemic-associated pain worsening. Rumination scores of the Pain Catastrophizing Scale were lower during t1 compared to before the pandemic regulations (t0: 7.81 ± 4.70, t1: 6.49 ± 4.39; P = 0.030). Interestingly, pain ratings for the last 7 days were higher in patients with a changed social life compared to those without (−1.63 ± 1.60 vs 0.31 ± 1.83; P = 0.01). Quality of life was decreased and helplessness increased in those with higher pain ratings.

Conclusion:

Results suggest a shift of attention from the chronic pain condition towards the imminent threat of a global pandemic. As the impacts of the pandemic are persistent and evolving, the development of the measured parameters in the forthcoming weeks will be of great interest.

A nociresponsive specific area of human somatosensory cortex within BA3a: BA3c?

It is well recognized that in primates, including humans, noxious body stimulation evokes a neural response in the posterior bank of the central sulcus, in Brodmann cytoarchitectonic subdivisions 3b and 1 of the primary somatosensory cortex. This response is associated with the 1st/sharp pain and contributes to sensory discriminative aspects of pain perception and spatial localization of the noxious stimulus. However, neurophysiological studies in New World monkeys predict that in humans noxious stimulation also evokes a separate neural response-mediated by C-afferent drive and associated with the 2nd/burning pain-in the depth of the central sulcus in Brodmann area 3a (BA3a) at the transition between the somatosensory and motor cortices. To evoke such a response, it is necessary to use multi-second duration noxious stimulation, rather than brief laser pulses. Given the limited human pain-imaging literature on cortical responses induced by C-nociceptive input specifically within BA3a, here we used high spatial resolution 7T fMRI to study the response to thermonoxious skin stimulation. We observed the predicted response of BA3a in the depth of the central sulcus in five human volunteers. Review of the available evidence suggests that the nociresponsive region in the depth of the central sulcus is a structurally and functionally distinct cortical area that should not be confused with proprioceptive BA3a. It is most likely engaged in interoception and control of the autonomic nervous system, and contributes to the sympathetic response to noxious stimulation, arguably the most intolerable aspect of pain experience. Ablation of this region has been shown to reduce pain sensibility and might offer an effective means of ameliorating some pathological pain conditions.

Cognitive Biases Toward Pain: Implications for a Neurocognitive Processing Perspective in Chronic Pain and its Interaction With Depression

OBJECTIVES

Information-processing biases such as attentional, interpretation, and memory biases are supposed to play a role in the exacerbation and maintenance of chronic pain. Current research in the area of cognitive biases shows that all these biases seem to have an influence on attention to, interpretation of, and recall of pain and can lead to maladaptive strategies and the exacerbation of pain.

METHODS

We conducted a narrative literature review, considering evidence extracted from various databases including PubMed, MEDLINE, Science Direct, and ProQuest. Search terms included cognitive biases, neurocognitive processing, chronic pain, and depression.

RESULTS

The literature on attentional, interpretative, and memory biases in experimental and chronic pain, as well as their neuronal underpinnings, suggests that the depression of chronic pain patients may differ from the depression of patients without pain. Depressed pain patients show a recall bias for illness-related and health-related stimuli, whereas depressed patients without pain show a bias for depression-related stimuli. In addition, research has shown that catastrophizing, helplessness/hopelessness, and thought suppression as psychological responses to pain are mediators of the relationship between chronic pain and depression.

CONCLUSIONS

Current research supports the importance of individual diagnosis of chronic pain patients and their response patterns of pain, psychological processing, and information processing. This leads to the conclusion that depressed pain patients need other clinical interventions when compared with depressed patients without pain. Previous research showed that a combination of a cognitive-behavioral therapy with mindfulness meditation seems to be a promising approach.

Dorsal Root Ganglion Stimulation Modulates Cortical Gamma Activity in the Cognitive Dimension of Chronic Pain

A cognitive task, the n-back task, was used to interrogate the cognitive dimension of pain in patients with implanted dorsal root ganglion stimulators (DRGS). Magnetoencephalography (MEG) signals from thirteen patients with implanted DRGS were recorded at rest and while performing the n-back task at three increasing working memory loads with DRGS-OFF and the task repeated with DRGS-ON. MEG recordings were pre-processed, then power spectral analysis and source localization were conducted. DRGS resulted in a significant reduction in reported pain scores (mean 23%, p = 0.001) and gamma oscillatory activity (p = 0.036) during task performance. DRGS-induced pain relief also resulted in a significantly reduced reaction time during high working memory load (p = 0.011). A significant increase in average gamma power was observed during task performance compared to the resting state. However, patients who reported exacerbations of pain demonstrated a significantly elevated gamma power (F(3,80) = 65.011612, p < 0.001, adjusted p-value = 0.01), compared to those who reported pain relief during the task. Our findings demonstrate that gamma oscillatory activity is differentially modulated by cognitive load in the presence of pain, and this activity is predominantly localized to the prefrontal and anterior cingulate cortices in a chronic pain cohort.

Induced oscillatory signaling in the beta frequency of top-down pain modulation

Supplemental Digital Content is Available in the Text.

Background:

Induced synchronized brain activity, particularly in the beta-frequency range, has rarely been investigated in human electrophysiological studies of attentional modulation of the perception of nociceptive stimuli.

Methods:

We measured time-resolved brain responses to nociceptive stimuli in healthy subjects (final data set: n = 17) using magnetoencephalography (MEG). In addition to investigating evoked responses as previous studies, we tested whether synchronized beta activity induced by nociceptive stimuli differs between 2 attentional conditions. Subjects were presented simultaneously with 2 stimulus modalities (pain-producing intraepidermal electrical stimuli and visual stimuli) in 2 different experimental conditions, ie, “attention to pain” and “attention to color.” Pain ratings between conditions were compared using a 2-sided paired-sample t test; MEG data were analyzed with Brainstorm.

Results:

Pain ratings were significantly higher in the “attention to pain” compared with the “attention to color” condition. Peak amplitudes of the evoked responses were significantly larger in the “attention to pain” condition bilaterally in the insula and secondary somatosensory cortex, and in the primary somatosensory cortex (SI) contralateral to stimulation. Induced responses to painful stimuli were significantly stronger in contralateral SI in the beta-frequency range in the “attention to pain” condition.

Conclusions:

This study replicates previous reports w.r.t. the attentional modulation of evoked responses and suggests a functional role of induced oscillatory activity in the beta frequency in top-down modulation of nociceptive stimuli.

Investigating the Influence and a Potential Mechanism of Self-Compassion on Experimental Pain: Evidence From a Compassionate Self-Talk Protocol and Heart Rate Variability

Previous studies have indicated a positive relationship between self-compassion and psychological and emotional well-being in chronic pain populations. However, evidence on the role and mechanisms of self-compassion in pain perception is largely limited. The current study was designed to investigate the effects and a potential mechanism of self-compassion on experimental pain. Thirty healthy participants underwent a compassionate self-talk protocol, which was followed by cold pain exposure during which high-frequency heart rate variability (HF-HRV) was evaluated. The compassionate self-talk protocol successfully generated compassionate statements among the participants. Our behavioral data showed lower pain ratings in the self-compassion compared to the control condition. Moreover, self-compassion manipulation resulted in higher HF-HRV during pain, which was associated with lower pain ratings. We present interesting findings that a short period of compassionate self-talk may decrease experimental pain as well as mechanistic evidence surrounding bodily control over pain-related arousal indicated by HF-HRV. PERSPECTIVE: This study presents the first line of evidence that a short period of compassionate self-talk may be sufficient to reduce experimental pain. We also demonstrate increased bodily control as a potential mechanism underlying this effect.

Pain and Distraction According to Sensory Modalities: Current Findings and Future Directions

BACKGROUND

This review discusses the findings in the literature on pain and distraction tasks according to their sensory modality. Distraction tasks have been shown to reduce (experimentally induced) acute pain and chronic pain. This can be influenced by nature and by the sensory modalities used in the distraction tasks. Yet the effect on reducing pain according to the sensory modality of the distraction task has received little attention.

METHODS

A bibliographic search was performed in different databases. The studies will be systematized according to the sensory modality in which the distraction task was applied.

RESULTS

The analyzed studies with auditory distractors showed a reduction of acute pain in adults. However, these are not effective at healthy children and in adults with chronic pain. Visual distractors showed promising results in acute pain in adults and children. Similarly, tactile and mixed distractors decreased acute pain in adults.

CONCLUSION

Distraction tasks by diverse sensory modalities have a positive effect on decreasing the perception of acute pain in adults. Future studies are necessary given the paucity of research on this topic, particularly with tactile distractors (there is only one study). Finally, the most rigorous methodology and the use of ecological contexts are encouraged in future research.

Integration of bilateral nociceptive inputs tunes spinal and cerebral responses

Together with the nociceptive system, pain protects the body from tissue damage. For instance, when the RIII-reflex is evoked by sural nerve stimulation, nociceptive inputs activate flexor muscles and inhibit extensor muscles of the affected lower limb while producing the opposite effects on the contralateral muscles. But how do the spinal cord and brain integrate concurrent sensorimotor information originating from both limbs? This is critical for evoking coordinated responses to nociceptive stimuli, but has been overlooked. Here we show that the spinal cord integrates spinal inhibitory and descending facilitatory inputs during concurrent bilateral foot stimulation, resulting in facilitation of the RIII-reflex and bilateral flexion. In these conditions, high-gamma oscillation power was also increased in the dorsolateral prefrontal, anterior cingulate and sensorimotor cortex, in accordance with the involvement of these regions in cognitive, motor and pain regulation. We propose that the brain and spinal cord can fine-tune nociceptive and pain responses when nociceptive inputs arise from both lower limbs concurrently, in order to allow adaptable behavioural responses.

Cingulate-mediated approaches to treating chronic pain

Anterior midcingulate cortex (aMCC) has been shown to be involved in most of the functional imaging studies investigating acute pain. For 10-15 years, it has even been a main focus of interest for pain studies, considering that neurons in the aMCC could encode for pain intensity. This latter function is now presumed to occur in secondary somatosensory (SII) area and/or insular cortices, while anterior cingulate cortex (ACC) is supposed to sustain other functions such as pain-related attention, arousal, motor withdrawal reflex, pain modulations, and engagement of endogenous pain control system. The quantitative imaging studies have shown a rich density of opioid receptors in the ACC. Thus, the perigenual subdivision has been suggested to participate in top-down controls of pain, (including the placebo effects known to be opioid mediated), mainly (but not exclusively) through the connection between the orbitofrontal/subgenual ACC and the periaqueductal gray (PAG). From this rationale, this area may lead to neurosurgical targeting including electrical stimulation for intractable pain in the future. A number of imaging studies have also reported activity changes in the posterior cingulate cortex during pain and proposed its speculative involvement to modulate the conscious experience of pain according to elements from the context and awareness of the self and others.

Paediatric Pain Medicine: Pain Differences, Recognition and Coping Acute Procedural Pain in Paediatric Emergency Room

Paediatric pain and its assessment and management are challenging for medical professionals, especially in an urgent care environment. Patients in a paediatric emergency room (PER) often undergo painful procedures which are an additional source of distress, anxiety, and pain. Paediatric procedural pain is often underestimated and neglected because of various myths, beliefs, and difficulties in its evaluation and treatment. However, it is very different from other origins of pain as it can be preventable. It is known that neonates and children can feel pain and that it has long-term effects that last through childhood into adulthood. There are a variety of pain assessment tools for children and they should be chosen according to the patient’s age, developmental stage, communication skills, and medical condition. Psychological factors such as PER environment, preprocedural preparation, and parental involvement should also be considered. There are proven methods to reduce a patient’s pain and anxiety during different procedures in PER. Distraction techniques such as music, videogames, virtual reality, or simple talk about movies, friends, or hobbies as well as cutaneous stimulation, vibration, cooling sprays, or devices are effective to alleviate procedural pain and anxiety. A choice of distraction technique should be individualized, selecting children who could benefit from nonpharmacological pain treatment methods or tools. Nonpharmacological pain management may reduce dosage of pain medication or exclude pharmacological pain management. Most nonpharmacological treatment methods are cheap, easily accessible, and safe to use on every child, so it should always be a first choice when planning a patient’s care. The aim of this review is to provide a summary of paediatric pain features, along with their physiology, assessment, management, and to highlight the importance and efficacy of nonpharmacological pain management in an urgent paediatric care setting.

Delineation between different components of chronic pain using dimension reduction - an ASL fMRI study in hand osteoarthritis

Background

Traditional psychometric measures aimed at characterizing the pain experience often show considerable overlap, due to interlinked affective and modulatory processes under central nervous system control. Neuroimaging studies have been employed to investigate this complexity of pain processing, in an attempt to provide a quantifiable, adjunctive description of pain perception. In this exploratory study, we examine psychometric and neuroimaging data from 38 patients with painful osteoarthritis of the carpometacarpal joint. We had two aims: first, to utilize principal component analysis (PCA) as a dimension reduction strategy across multiple self‐reported endpoints of pain, cognitive and affective functioning; second, to investigate the relationship between identified dimensions and regional cerebral blood flow (rCBF) as an indirect measure of brain activity underpinning their ongoing pain experiences.

Methods

Psychometric data were collected using validated questionnaires. Quantitative estimates of rCBF were acquired using pseudo‐continuous arterial spin‐labelled functional magnetic resonance imaging.

Results

Two principal components were identified that accounted for 73% of data variance; one related to pain scores and a second to psychological traits. Voxel‐wise multiple regression analysis revealed a significant negative association between the ‘pain score’ component and rCBF to a right temporal lobe cluster, including the amygdala and the parahippocampal cortex.

Conclusion

We suggest this association may represent a coping mechanism that aims to reduce fear‐related pain‐anxiety. Further investigation of central brain processing mechanisms in osteoarthritis‐related pain may offer insights into more effective therapeutic strategies.

Significance

This study demonstrates that dimension reduction using PCA allows insight into pain perception and its affective components in relation to brain activation patterns in patients with painful hand osteoarthritis.

Shockwave lithotripsy with music: Less painful and more satisfactory treatment

INTRODUCTION

The objective of this study was to determine whether listening to music during a session of extracorporeal shockwave lithotripsy (ESWL) improves patients' pain.

MATERIAL AND METHOD

A simple, blind randomisation was undertaken of patients with kidney and ureter stones attending an ESWL session of 7,000 waves for the first time, between September and December 2014. One group was given music and the other was not. The age, gender, location of stones (kidney/ureter) were recorded and 2questionnaires: pre ESWL (questionnaire A) and postESWL (questionnaire B). Each questionnaire contained a question about anxiety and another question on pain on the Likert scale (0-10). Questionnaire B also had a question on satisfaction and comfort (Likert 0-10). Other variables included heart rate, respiratory rate, systolic and diastolic blood pressure on wave 2,000, 5,000 and 7,000, reason for halting the procedure, total pethidine (mg), secondary analgesia, energy (J) and frequency (Hz). Bivariate analysis using the Student's t-test, X²/Fisher test and a multiple linear regression model.

RESULTS

The sample comprised 95 patients, with a mean age of 52 (±13) years, 35 (36.84%) females, 60 (63.2%) males. A total of 25 (26.3%) ureter stones and 70 (73.7%) kidney stones. A number of 42 (44.2%) patients were given music. There were no differences between the demographic variables or questionnaire A scores. Satisfaction and pain were better on questionnaire B with music.

CONCLUSION

Music can reduce pain and improve patient satisfaction in ESWL treatment. More studies are required to confirm this effect.

Disruption of default mode network dynamics in acute and chronic pain states

It has been proposed that pain competes with other attention-demanding stimuli for cognitive resources, and many chronic pain patients display significant attention and mental flexibility deficits. These alterations may result from disruptions in the functioning of the default mode network (DMN) which plays a critical role in attention, memory, prospection and self-processing, and recent investigations have found alterations in DMN function in multiple chronic pain conditions. Whilst it has been proposed that these DMN alterations are a characteristic of pain that is chronic in nature, we recently reported altered oscillatory activity in the DMN during an acute, 5  minute noxious stimulus in healthy control subjects. We therefore hypothesize that altered DMN activity patterns will not be restricted to those in chronic pain but instead will also occur in healthy individuals during tonic noxious stimuli. We used functional magnetic resonance imaging to measure resting state infra-slow oscillatory activity and functional connectivity in patients with chronic orofacial pain at rest and in healthy controls during a 20-minute tonic pain stimulus. We found decreases in oscillatory activity in key regions of the DMN in patients with chronic pain, as well as in healthy controls during tonic pain in addition to changes in functional connectivity between the posterior cingulate cortex and areas of the DMN in both groups. The results show that similar alterations in DMN function occur in healthy individuals during acute noxious stimuli as well as in individuals with chronic pain. These DMN changes may reflect the presence of pain per se and may underlie alterations in attentional processes that occur in the presence of pain.

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Default mode network dynamics were measured in chronic and acute pain.

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Altered infra-slow activity and connectivity occurred in chronic and acute pain.

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Default mode network changes characterize pain per se.