Pain and the context

Observed and Perceived Pain: Findings of a Cross-Sectional Study in Hospitalized Subjects

BACKGROUND

Pain constitutes a serious problem of a health, economic, ethical, and social equity nature affecting negatively quality of life. Its assessment is often subjected to overestimation or underestimation.

AIM

The aim of this study is threefold: (1) to estimate the prevalence of pain in hospitalized patients; (2) to assess the grade of correlation between the level of pain observed by the nurses and the pain perceived by the patients; and (3) to examine the level of scientific knowledge among the healthcare professionals.

DESIGN

Cross-sectional study.

METHODS

The intensity level of observed and perceived pain has been evaluated in 401 patients with validated scales. Analyzed data have been extracted from the electronic medical record and integrated into the data-collection sheet. A questionnaire has been submitted to nurses to investigate their level of knowledge on pain assessment and management.

RESULTS

The study included 350 patients out of 401; for 51 patients the "pain" data was missing. Prevalence of perceived pain was 40.15%. Nurses overestimated pain in 7.43% of cases and underestimated it in 24.9%. The majority of the nursing staff claimed to be aware of the pain topic, however, they showed some uncertainties in clinical practice.

CONCLUSIONS

The differential variation between the observed pain and the perceived one resulted in 43.71% of cases, highlighting the dependence on the two variables: "area of hospitalization" and "intensity level". The observation and monitoring of pain did not appear to be a consolidated practice, thus representing an important area for investments in the nursing profession.

Modulatory Processes in Craniofacial Pain States

Pain is a common symptom associated with many disorders affecting the craniofacial tissues that include the teeth and their supporting structures, the jaw, face and tongue muscles, and the temporomandibular joint. Most acute craniofacial pain states are easily recognized and readily treated, but chronic craniofacial pain states (e.g., temporomandibular disorders [TMD], trigeminal neuropathies, and some headaches) may be especially challenging to manage successfully. This chapter provides an overview of the processes that underlie craniofacial pain, with a focus on the pain-modulatory mechanisms operating in craniofacial tissues and in the central nervous system (CNS), including the role of endogenous chemical processes such as those involving opioids. The chapter outlines in particular findings from preclinical studies that have provided substantial information about the neural as well as nonneural (e.g., glial) processes involved in the initiation, transmission, and modulation of nociceptive signals in the trigeminal system, and also draws attention to their clinical correlates. The increased understanding gained from these preclinical studies of how nociceptive signals can be modulated will contribute to improvements in presently available therapeutic approaches to manage craniofacial pain as well as to the development of novel analgesic approaches.

Placebo and nocebo effects and mechanisms associated with pharmacological interventions: an umbrella review

OBJECTIVES

This review aimed to summarise the existing knowledge about placebo and nocebo effects associated with pharmacological interventions and their mechanisms.

DESIGN

Umbrella review, adopting the Assessment of Multiple Systematic Reviews 2 tool for critical appraisal.

DATA SOURCES

MEDLINE/PubMed, Scopus, Web of Science, PsycINFO, Cochrane Central Register of Controlled Trial were searched in September 2022, without any time restriction, for systematic reviews, narrative reviews, original articles. Results were summarised through narrative synthesis, tables, 95% CI.

OUTCOME MEASURES

Mechanisms underlying placebo/nocebo effects and/or their effect sizes.

RESULTS

The databases search identified 372 studies, for a total of 158 312 participants, comprising 41 systematic reviews, 312 narrative reviews and 19 original articles. Seventy-three per cent of the examined systematic reviews were of high quality.Our findings revealed that mechanisms underlying placebo and/or nocebo effects have been characterised, at least in part, for: pain, non-noxious somatic sensation, Parkinson's disease, migraine, sleep disorders, intellectual disability, depression, anxiety, dementia, addiction, gynaecological disorders, attention-deficit hyperactivity disorder, immune and endocrine systems, cardiovascular and respiratory systems, gastrointestinal disorders, skin diseases, influenza and related vaccines, oncology, obesity, physical and cognitive performance. Their magnitude ranged from 0.08 to 2.01 (95% CI 0.37 to 0.89) for placebo effects and from 0.32 to 0.90 (95% CI 0.24 to 1.00) for nocebo effects.

CONCLUSIONS

This study provides a valuable tool for clinicians and researchers, identifying both results ready for clinical practice and gaps to address in the near future.

FUNDING

Università Cattolica del Sacro Cuore, Milan, Italy with the 'Finanziamento Ponte 2022' grant.

PROSPERO REGISTRATION NUMBER

CRD42023392281.

Decreased gray matter volume in regions associated with affective pain processing in unmedicated individuals with nonsuicidal self-injury

Nonsuicidal self-injury (NSSI) has been consistently associated with a reduced aversion to physical pain. Yet, little research has been done to investigate the brain structures related to pain in individuals with NSSI. This study examined gray matter volume patterns of pain processing regions in participants engaging in NSSI (n = 63) and age-, sex-, and handedness-matched healthy controls (n = 63). Voxel-based morphometry was performed to explore gray matter volume in regions of interest (ROIs) and partial correlation analyses were conducted to identify their associations with the frequency, versatility, duration, functions, and pain intensity of self-injury. As a result, significant volume decreases were found in the right anterior insula, bilateral secondary somatosensory cortex (SII), and left inferior frontal gyrus. Moreover, individuals with smaller anterior insula and SII volume showed a higher likelihood of endorsing affect-regulation and sensation-seeking functions of NSSI, as well as engaging in self-injury with a greater perceived intensity of pain. Our results provide the first empirical evidence that individuals with NSSI may exhibit distinct characteristics in brain regions associated with the affective component of pain processing. These neurobiological changes may be associated with their maladaptive response to noxious and painful NSSI experiences.

The Biology of Placebo and Nocebo Effects on Experimental and Chronic Pain: State of the Art

(1) Background: In recent years, placebo and nocebo effects have been extensively documented in different medical conditions, including pain. The scientific literature has provided strong evidence of how the psychosocial context accompanying the treatment administration can influence the therapeutic outcome positively (placebo effects) or negatively (nocebo effects). (2) Methods: This state-of-the-art paper aims to provide an updated overview of placebo and nocebo effects on pain. (3) Results: The most common study designs, the psychological mechanisms, and neurobiological/genetic determinants of these phenomena are discussed, focusing on the differences between positive and negative context effects on pain in experimental settings on healthy volunteers and in clinical settings on chronic pain patients. Finally, the last section describes the implications for clinical and research practice to maximize the medical and scientific routine and correctly interpret the results of research studies on placebo and nocebo effects. (4) Conclusions: While studies on healthy participants seem consistent and provide a clear picture of how the brain reacts to the context, there are no unique results of the occurrence and magnitude of placebo and nocebo effects in chronic pain patients, mainly due to the heterogeneity of pain. This opens up the need for future studies on the topic.

Red induces hyperalgesia and white induces hypoalgesia regardless of pain modality

Colors are an important factor that influences different aspects of people's lives. However, little is known about the effects of colors on pain. This preregistered study aimed to investigate whether the type of pain affects the impact of colors on pain intensity. 74 participants were randomly divided into 2 groups according to the type of pain: electrical or thermal. In both groups, pain stimuli of the same intensity were preceded by different colors. Participants rated the pain intensity induced by each pain stimulus. Additionally, pain expectations related to each color were rated at the beginning and the end of the procedure. A significant effect of color on pain intensity ratings was found. Pain was most intense in both groups after red, whereas the lowest ratings were given after white. A similar pattern of results was observed for pain expectations. Expectations also correlated with and were found to be a predictor of experienced pain for white, blue, and green. The study shows that white can reduce, while red can alter the experienced pain. Moreover, it shows that the effect of colors is affected to a greater extent by the pain expectations rather than the pain modality. We conclude that the way colors influence pain broadens the current knowledge on effects of colors on human behavior and could help in the future both patients and practitioners.

Complexity theory in the management of patients with musculoskeletal pain

Nonlinear systems are not susceptible to research with a reductionist approach. In this sense, the complexity theory provides an alternative approach to quantify the importance of contextual factors in patients with musculoskeletal pain. The use of positive (placebo) or negative (nocebo) contextual factors in the therapeutic setting could largely account for the non-specific component of treatment efficacy, directly affecting the quality of patients’ health-related outcomes (e.g., pain, disability, or satisfaction). In recent years, there has been a better understanding of the effects of contextual factors. However, the knowledge and awareness of them is limited and heterogeneous among physical therapists, reducing their translational value in the field of physiotherapy. The purpose of this essay is to describe the management of patients with musculoskeletal pain from the complexity theory perspective.

Beating Pain with Psychedelics: Matter over Mind?

Basic pain research has shed light on key cellular and molecular mechanisms underlying nociceptive and phenomenological aspects of pain. Despite these advances, [[we still yearn for] the discovery of novel therapeutic strategies to address the unmet needs of about 70% of chronic neuropathic pain patients whose pain fails to respond to opioids as well as to other conventional analgesic agents. Importantly, a substantial body of clinical observations over the past decade cumulatively suggests that the psychedelic class of drugs may possess heuristic value for understanding and treating chronic pain conditions. The present review presents a theoretical framework for hitherto insufficiently understood neuroscience-based mechanisms of psychedelics' potential analgesic effects. To that end, searches of PubMed-indexed journals were performed using the following Medical Subject Headings' terms: pain, analgesia, inflammatory, brain connectivity, ketamine, psilocybin, functional imaging, and dendrites. Recursive sets of scientific and clinical evidence extracted from this literature review were summarized within the following key areas: (1) studies employing psychedelics for alleviation of physical and emotional pain; (2) potential neuro-restorative effects of psychedelics to remediate the impaired connectivity underlying the dissociation between pain-related conscious states/cognitions and the subcortical activity/function leading to the eventual chronicity through immediate and long-term effects on dentritic plasticity; (3) anti-neuroinflammatory and pro-immunomodulatory actions of psychedelics as the may pertain to the role of these factors in the pathogenesis of neuropathic pain; (4) safety, legal, and ethical consideration inherent in psychedelics' pharmacotherapy. In addition to direct beneficial effects in terms of reduction of pain and suffering, psychedelics' inclusion in the analgesic armamentarium will contribute to deeper and more sophisticated insights not only into pain syndromes but also into frequently comorbid psychiatric condition associated with emotional pain, e.g., depressive and anxiety disorders. Further inquiry is clearly warranted into the above areas that have potential to evolve into further elucidate the mechanisms of chronic pain and affective disorders, and lead to the development of innovative, safe, and more efficacious neurobiologically-based therapeutic approaches.

Treatment journey in rheumatoid arthritis with biosimilars: from better access to good disease control through cost savings and prevention of nocebo effects

Early diagnosis and treatment of rheumatoid arthritis (RA) are of critical importance to halt the progression of the disease. Optimal use of advanced imaging techniques or biomarkers may facilitate early diagnosis of RA. Even though many disease-modifying anti-rheumatic drugs (DMARDs) are available for RA treatment, biological DMARDs (bDMARDs) offer expanding therapeutic options and good outcomes in patients with RA who do not have a sufficient response to conventional synthetic DMARDs. However, high costs of bDMARDs have limited patient access to optimised disease management and increased the cost burden for healthcare systems. The advent of biosimilars led to significant cost savings driven by price competition among the reference products, which could be beneficial for healthcare systems. Healthcare provider (HCP)–patient communication and informed shared decision-making are crucial to prevent the occurrence of a nocebo effect, which results from negative perceptions that patients may have and could lead to less effective outcomes. Research has demonstrated that effective communication between HCPs and patients utilising positive framing can improve acceptance by patients to be initiated on or switched to a biosimilar and can help to integrate biosimilars into routine clinical practice to maximise benefits for patients with RA.

The Nocebo Effect: A Review of Contemporary Experimental Research

BACKGROUND

Nocebo effect, the occurrence of adverse symptoms fallowing an inactive treatment, is much less understood than its opposite, placebo effect. This systematic review of contemporary studies exploring the nocebo effect focuses on (1) the mechanisms underlying the nocebo effect, (2) the characteristics of participants exhibiting a more intensive nocebo response, and (3) the circumstances that might reduce or prevent the nocebo effect.

METHOD

We included experimental nocebo studies published in English that examined the occurrence of nocebo in various domains (i.e., types of sensations and symptoms) and different levels of nocebo response (e.g., performance, self-assessment) and in different populations of participants (healthy and clinical). Using Web of Science, PsycInfo and PubMed, we identified 25 papers (35 studies) that met our criteria with a total of N = 2614 participants, mostly healthy volunteers.

RESULTS

Nocebo was invoked by manipulating expectations, conditioning or both. A narrative content synthesis was conducted. Nocebo was successfully invoked in a range of domains (e.g., pain, nausea, itch, skin dryness) and levels (sensory, affective, psychological, and behavioral). Various characteristics of the conditioning procedure and participants' emotions, expectations, and dispositions are found to be related to the nocebo response, which sheds insight into the possible mechanisms of the nocebo effect. Strategies successful and unsuccessful in diminishing the nocebo response are identified. Limitations of this review include a small sample of studies.

CONCLUSION

These findings point to the universality of nocebo as well as to the importance of participant characteristics and experimental circumstances in invoking the nocebo effect. Further research should examine the nocebo effect in clinical populations.

Touch and social support influence interpersonal synchrony and pain

Interpersonal touch and social support can influence physical health, mental well-being and pain. However, the mechanisms by which supportive touch promotes analgesia are not well understood. In Study 1, we tested how three kinds of social support from a romantic partner (passive presence, gentle stroking and handholding) affect pain ratings and skin conductance responses (SCRs). Overall, support reduced pain ratings in women, but not men, relative to baseline. Support decreased pain-related SCRs in both women and men. Though there were no significant differences across the three support conditions, effects were largest during handholding. Handholding also reduced SCRs in the supportive partner. Additionally, synchronicity in couples’ SCR was correlated with reductions in self-reported pain, and individual differences in synchrony were correlated with the partner’s trait empathy. In Study 2, we re-analyzed an existing dataset to explore fMRI activity related to individual differences in handholding analgesia effects in women. Increased activity in a distributed set of brain regions, including valuation-encoding frontostriatal areas, was correlated with lower pain ratings. These results may suggest that social support can reduce pain by changing the value of nociceptive signals. This reduction may be moderated by interpersonal synchrony and relationship dynamics.

Understanding Contextual Factors Effects and Their Implications for Italian Physiotherapists: Findings from a National Cross-Sectional Study

An online cross-sectional survey was conducted using Google Docs software. The aim was to understand the management of contextual factors and to identify which are most relevant and which clinicians underestimate. A total of 1250 physiotherapists were chosen from the database of the Manual Therapists group mailing list (GTM-IFOMPT MO) from July to August 2020. A total of 699 responses were received that were considered valid (56%). Participants (40.83%) identified contextual factors (CFs) as "any element, even involuntary, with which the patient interacts during treatment". Physiotherapists individually chose the representation of CF with the "therapeutic relationship" (82.9%), followed by "therapeutic setting" (75.8%). This choice differed between participants belonging to different age groups. Participants favor communication strategies (76.93%). More than half (57.88%) pay attention to patient involvement during the course of care; and in response to the patients' doubts about the use of treatments with limited scientific efficacy, they suggest different medical treatments. The patient's previous clinical experience is not considered significant and does not influence the choice of treatment. Subsequently, however, the participants reported that they stimulate the patients' positive expectations of the success of the clinical outcome (45.27%). Knowledge of contextual factors in physiotherapy appears limited and very heterogeneous. Future research could increase the focus on professional development.

Offset analgesia and onset hyperalgesia with different stimulus ranges

A comparison between the effects of offset analgesia and onset hyperalgesia and how these effects relate to the stimulus range of thermal stimulation.

Introduction:

Offset analgesia (OA), a large reduction in pain after a brief increase in intensity of an otherwise stable painful stimulus, has been established by a large body of research. But the opposite effect, onset hyperalgesia (OH), a disproportional hyperalgesic response after a briefly decreased intensity of a painful stimulus, has only been investigated in one previous study.

Objectives:

The aim of this study was to induce OA and OH in healthy participants and explore the effects of different stimulus ranges (increase/decrease of temperature) on OA and OH.

Methods:

A total of 62 participants were tested in 2 identical experiments. Offset analgesia and OH conditions included 2 different temperature deviations (±1°C/±2°C) from initial temperature and were compared with a constant temperature (control).

Results:

Offset analgesia was successfully elicited in OA_1°C in experiment 1, and in OA_1°C and OA_2°C in experiment 2. Results indicate a continuous stimulus–response relationship between the stimulus range and the resulting hypoalgesic response. Onset hyperalgesia was only elicited in OH_2°C in experiment 1. Exploratory analysis showed that the lack of OH response in experiment 2 could be explained by sex differences, and that OA and OH responses were only weakly correlated.

Conclusions:

The asymmetry between pain responses after a brief temperature increase and decrease suggests that different mechanisms are involved in the pain responses to increasing and decreasing temperature. This asymmetry may also be explained by high temperatures in OA condition (+1°C/+2°C above baseline) that could be seen as salient “learning signals,” which augment the response to following changes in temperature.

A Meta-Analysis of Group-Based Pain Management Programs: Overall Effect on Quality of Life and Other Chronic Pain Outcome Measures, with an Exploration into Moderator Variables that Influence the Efficacy of Such Interventions

OBJECTIVES

Group-based pain management programs (GPMPs) have been found to significantly improve quality of life and other pain outcome measures in patients with chronic musculoskeletal pain. The aims of this meta-analysis were to reevaluate the overall effect of GPMPs on various pain outcomes for individuals experiencing chronic musculoskeletal conditions and to explore moderator variables that potentially contribute to the overall efficacy of GPMPs.

METHODS

Using the R package called metaphor and RevMan, we estimated the overall effectiveness of GPMPs on various pain outcome measures. The differential effectiveness of GPMPs was examined by conducting a mixed-effects meta-analytic model using various study-level characteristics. Moderator analyses included three content moderator variables and seven format moderator variables. Receiver operating characteristic curves investigated optimal points in some of the moderator variable analysis results.

RESULTS

Significant overall main effects of GPMPs were found on all the explored outcome measures in this study (P < 0.05). In moderator analyses, it was found that the structure of GPMPs, rather than the content, significantly improved outcomes (P < 0.05). Receiver operating characteristic curve analyses identified the optimal number of GPMP sessions and number of participants per group.

DISCUSSION AND CLINICAL RELEVANCE

GPMPs have a statistically significant overall effect on all explored pain outcome measures. The investigation into content and structural moderators suggests that certain GPMP design factors have a greater effect on pain outcomes than do content factors. Therefore, GPMP structural designs appear to be important in reducing pain and improving quality of life for patients with chronic pain and warrant further investigation.

Feasibility of high dose medical exercise therapy in patients with long-term symptomatic knee osteoarthritis

Purpose: High repetition high dose medical exercise therapy (MET) is a promising treatment for patients with musculoskeletal pain. However, little is known regarding the feasibility of MET in patients with symptomatic knee osteoarthritis (OA). The aim of this study was to investigate the feasibility of MET in patients with symptomatic knee pain with radiographic verified OA.Methods: Patients with symptomatic knee osteoarthritis were recruited to a group-based high repetitive high dose MET intervention for 12 weeks in a primary health care setting. Indicators of feasibility included processes (recruitment, program adherence, and exercise compliance), and scientific feasibility (safety and pain evaluated by using the Visual Analogue Scale (VAS)).Results: Out of 31 individuals with symptomatic knee OA, 29 (93%) were included in this study. A total of 26 patients (90%) completed the intervention and 83% reached an attendance rate of ≥30 treatments. No adverse events were reported, and a majority of the patients reported a pain intensity <30 mm (VAS) throughout the intervention period. The results showed a 70% reduction of median pain intensity between baseline (33 mm, IQR: 39), and post-assessment (10 mm, IQR: 25, P = .003).Conclusion: These findings support an overall positive feasibility of MET for patients with symptomatic knee OA. The results also demonstrated that achieving a high dose of exercises might be challenging for this population. Thus, individual variations in exercise dose may be a confounding factor when evaluating high dose MET in future clinical studies.

The subthalamic nucleus and the placebo effect in Parkinson's disease

The study of the placebo effect, or response, is related to the investigation of the psychologic component of different therapeutic rituals. The high rate of placebo responses in Parkinson's disease clinical trials provided the impetus for investigating the underlying mechanisms. Ruling out spontaneous remission and regression to the mean through the appropriate experimental designs, genuine psychologic placebo effects have been identified, in which both patients' expectations of therapeutic benefit and learning processes are involved. Specifically, placebo effects are associated with dopamine release in the striatum and changes in neuronal activity in the subthalamic nucleus, substantia nigra pars reticulata, and motor thalamus in Parkinson's disease, as assessed through positron emission tomography and single-neuron recording during deep brain stimulation, respectively. Conversely, verbal suggestions of clinical worsening or drug dose reduction induce nocebo responses in Parkinson's disease, which have been detected at both behavioral and electrophysiologic level. Important implications and applications emerge from this new knowledge. These include better clinical trial designs, whereby patients' expectations should always be assessed, as well as better drug dosage in order to reduce drug intake.

What Physiotherapists Specialized in Orthopedic Manual Therapy Know About Nocebo-Related Effects and Contextual Factors: Findings From a National Survey

Objective

The aim of this study was to investigate the knowledge of orthopedic manual therapists (OMTs) regarding context factors (CFs) capable of triggering nocebo effects during the treatment and how this knowledge is related to their socio-demographic features.

Design

A cross-sectional online survey.

Setting

National.

Main Outcome Measures

A 20 items questionnaire composed by open-ended and closed single-choice questions was administered to explore: (a) socio-demographic variables (10 questions); (b) the relation between different CFs and nocebo-related effects (2 questions); and (c) the knowledge of participants about nocebo-related effects and how they managed them in the clinical practice (8 questions).

Participants

1288 OMTs were recruited from the database of the Master in Rehabilitation of Musculoskeletal Disorders (MRDM) of the University of Genova from March to May 2019. Inclusion criteria were: (a) to possess a valid email account; (b) to understand and use as a native language the Italian; (c) to be graduated as OMTs; and (d) to be employed as physiotherapists specialized-OMTs during the survey.

Results

791 responses were received (61.4%); 473 of them were male (59.8%), with an average age of 31.0 ± 7.1 years. OMTs defined nocebo-related effects as the psychosocial context effects around therapy and patient with specific biological bases (72.2%). OMTs know that their clinical practice is pervaded by nocebo-related effects (42.5%), triggered by CFs. Participants communicated nocebo-related effects balancing the positive features of the therapy with the negative ones (50.9%), during the decision of the therapeutic plan (42.7%). They reported associative learning as the main mechanism involved in nocebo-related effects (28.8%). OMTs taught and trained patient’s strategies to manage nocebo-related effects (39.6%) through an evaluation and correction of patient’s anxieties, doubts and expectations (37.7%). OMTs most frequently considered themselves to have a “medium” education about nocebo-related effects (48.2%) and that their management should be taught during bachelor (78.6%).

Conclusion

OMTs believed that nocebo-related effects were present in their clinical practice and that they can be triggered by CFs.

Dynamic brain-to-brain concordance and behavioral mirroring as a mechanism of the patient-clinician interaction

The patient-clinician interaction can powerfully shape treatment outcomes such as pain but is often considered an intangible "art of medicine" and has largely eluded scientific inquiry. Although brain correlates of social processes such as empathy and theory of mind have been studied using single-subject designs, specific behavioral and neural mechanisms underpinning the patient-clinician interaction are unknown. Using a two-person interactive design, we simultaneously recorded functional magnetic resonance imaging (hyperscanning) in patient-clinician dyads, who interacted via live video, while clinicians treated evoked pain in patients with chronic pain. Our results show that patient analgesia is mediated by patient-clinician nonverbal behavioral mirroring and brain-to-brain concordance in circuitry implicated in theory of mind and social mirroring. Dyad-based analyses showed extensive dynamic coupling of these brain nodes with the partners' brain activity, yet only in dyads with pre-established clinical rapport. These findings introduce a putatively key brain-behavioral mechanism for therapeutic alliance and psychosocial analgesia.

The Bayesian brain in imbalance: Medial, lateral and descending pathways in tinnitus and pain: A perspective

Tinnitus and pain share similarities in their anatomy, pathophysiology, clinical picture and treatments. Based on what is known in the pain field, a heuristic model can be proposed for the pathophysiolgy of tinnitus. This heuristic pathophysiological model suggests that pain and tinnitus are the consequence of an imbalance between two pain/tinnitus evoking pathways, i.e., a lateral sensory pathway and a medial affective pathway, both of which are not balanced anymore by a pain/noise inhibitory pathway. Mechanistically, based on the Bayesian brain concept, it can be explained by a switch occuring under influence of the rostral to dorsal anterior cingulate cortex of its prior predictions, i.e., a reference resetting, in which the pain/tinnitus state is considered as the new reference state. This reference resetting is confirmed by the nucleus accumbens as part of the reward system and maintained by connectivity changes between the nucleus accumbens and the pregenual anterior cingulate cortex. As a consequence it can be suggested to treat pain/tinnitus via reconditioning, either surgically or non-surgically. The model can also be used to develop objective measures for tinnitus and pain via supervised machine learning.

Effects of an ethanolic extract and fractions from Piper glabratum (Piperaceae) leaves on pain and inflammation

In the state of Mato Grosso do Sul, Brazil, Piper glabratum leaves are used as a popular medicine for pain and inflammation. We performed a phytochemical analysis and evaluated the effects of ethanolic extract (EEPG) obtained from leaves of P. glabratum on toxicity as well as the effects of application of the hexanic fraction (HXPG) and the hydroalcoholic fraction (HAPG) obtained from the EEPG on inflammatory parameters and pain in mice. Swiss mice were treated with EEPG (30-300 mg/kg body weight (b.w.)), HXPG (19.5 mg/kg b.w.) or HAPG (83.37 mg/kg b.w.) and then subjected to carrageenan-induced pleurisy and paw oedema tests, the spontaneous pain, and zymosan-induced intra-articular inflammation. Wistar rats were treated with EEPG to assess acute toxicity. Phytochemical analysis of the fractions demonstrated the presence of phytol and mixture of stigmasterol and β-sitosterol in the fractions. In the acute toxicity test, LD50 above 2000 mg/kg b.w. was observed. The treatments reduced oedema, cold and mechanical hyperalgesia, leukocyte migration and protein exudation. The antihyperalgesic and anti-inflammatory properties of EEPG and fractions were demonstrated in the present study. These results from EEPG and HXPG may be related, at least in part, to modulation of the inflammatory mediators by phytol, stigmasterol and β-sitosterol.

Context matters: the psychoneurobiological determinants of placebo, nocebo and context-related effects in physiotherapy

Background

Placebo and nocebo effects embody psychoneurobiological phenomena where behavioural, neurophysiological, perceptive and cognitive changes occur during the therapeutic encounter in the healthcare context. Placebo effects are produced by a positive healthcare context; while nocebo effects are consequences of negative healthcare context. Historically, placebo, nocebo and context-related effects were considered as confounding elements for clinicians and researchers. In the last two decades this attitude started to change, and the understanding of the value of these effects has increased. Despite the growing interest, the knowledge and the awareness of using the healthcare context to trigger placebo and nocebo effects is currently limited and heterogeneous among physiotherapists, reducing their translational value in the physiotherapy field.

Objectives

To introduce the placebo, nocebo and context-related effects by: (1) presenting their psychological models; (2) describing their neurophysiological mechanisms; (3) underlining their impact for the physiotherapy profession; and (4) tracing lines for future researches.

Conclusion

Several psychological mechanisms are involved in placebo, nocebo and context-related effects; including expectation, learning processes (classical conditioning and observational learning), reinforced expectations, mindset and personality traits. The neurophysiological mechanisms mainly include the endogenous opioid, the endocannabinoid and the dopaminergic systems. Neuroimaging studies have identified different brain regions involved such as the dorsolateral prefrontal cortex, the rostral anterior cingulate cortex, the periaqueductal gray and the dorsal horn of spine. From a clinical perspective, the manipulation of the healthcare context with the best evidence-based therapy represents an opportunity to trigger placebo effects and to avoid nocebo effects respecting the ethical code of conduct. From a managerial perspective, stakeholders, organizations and governments should encourage the assessment of the healthcare context aimed to improve the quality of physiotherapy services. From an educational perspective, placebo and nocebo effects are professional topics that should be integrated in the university program of health and medical professions. From a research perspective, the control of placebo, nocebo and context-related effects offers to the scientific community the chance to better measure the impact of physiotherapy on different outcomes and in different conditions through primary studies.

Matching actual treatment with patient administration-route-preference improves analgesic response among acute low back pain patients-a randomized prospective trial

Background

Accommodating a patient’s treatment preference has been reported to promote greater responsiveness and better clinical outcomes. The effect of administration route preference (ARP) on the individual analgesic response has not been extensively examined to date. This study aimed to investigate whether ARP-matched treatment, i.e., individualized intramuscular (IM) or oral (PO) analgesic administration according to patient choice, would increase the analgesic effect.

Methods

In this prospective randomized study, we collected 38 patients with acute low back pain (aLBP) presenting at the emergency room of the Galilee Medical Center (Naharia, Israel) and asked them to report their ARP for analgesics. Regardless of their reported preference, they received either PO or IM diclofenac according to the treating physician’s preference. Pain intensity was self-reported using the numeric pain score (NPS) before and during the first hour after drug administration.

Results

Both groups receiving PO or IM administration reported similar initial pain on admission, (NPS 8.63 ± 1.5 and 8.74 ± 1.6, respectively) and the same magnitude of pain reduction. However, patients who received the drug in their desired route (oral or injection) had a significantly greater reduction in pain levels (4.05 ± 2.8) as compared with patients who received the undesired route (2.08 ± 1.8), p < 0.05.

Conclusions

These findings support the hypothesis that individualized ARP-matched treatment in aLBP improves therapeutic outcomes, although further studies with larger cohorts are needed.

Riding a Tiger: Maximizing Effects of Manual Therapies for Pelvic Pain

Manual therapy interventions are frequently used during the management of pelvic pain conditions. Pain relief after any intervention results from effects unrelated to the intervention, effects specific to the intervention, and effects of context in which the intervention is provided. Understanding these multiple mechanisms allows providers of manual therapy to maximize outcomes by deliberately harnessing each of these core elements of pain relief.

Chronic Fatigue Syndrome and chronic pain conditions - vitally protective systems gone wrong

Chronic Fatigue Syndrome (CFS) and chronic pain syndromes represent major health problems in society. These conditions are disabling and strongly associated with low quality of life. Even though CFS and chronic pain are separate conditions, they have strikingly much in common. Both pain and fatigue are important sensations with protective value in an acute situation. It can be life-threatening not to be aware of them. However, as these symptoms become chronic, their protective roles decrease and instead they become health problems. Our understanding of the perception of pain and fatigue has shifted through the years, from a dualistic biomedical point of view to a holistic biopsychosocial understanding. This combined with the increasing evidence of how our brain works in a predictive/anticipatory manner, gives a deeper understanding of why treatments like cognitive behavior therapies and stress relief therapies can help these patients recover to better health.

In search of a rodent model of placebo analgesia in chronic orofacial neuropathic pain

All treatments are given in a context, suggesting that conditioning cues may significantly influence therapeutic outcomes. We tested the hypothesis that context affects placebo analgesia in rodents. To produce neuropathic pain in rats, we performed chronic constriction injury of the infraorbital nerve. We then treated the rats daily, over a seven day period, with injections of either fentanyl or saline, with or without associated conditioning cues; a fourth group received no treatment. On the eighth day, we replaced fentanyl with saline to test for conditioned placebo analgesia. We tested the effects of treatment by measuring sensitivity to mechanical stimuli and grimace scale scores. We found no significant differences in either of these outcomes among the four experimental groups. These findings suggest that chronic, neuropathic pain in rats may not be susceptible to placebo analgesia.

The Knowledge of Contextual Factors as Triggers of Placebo and Nocebo Effects in Patients With Musculoskeletal Pain: Findings From a National Survey

Backgrounds: Contextual factors (CFs) have been recently proposed as triggers of placebo and nocebo effects in musculoskeletal pain. CFs encompass the features of the clinician (e.g. uniform), patient (e.g. expectations), patient-clinician relationship (e.g. verbal communication), treatment (e.g. overt therapy), and healthcare setting (e.g. design). To date, the researchers' understanding of Italian patients' knowledge about the role of CFs in musculoskeletal pain is lacking. Objectives: The aim of this study was to investigate attitudes and beliefs of Italian patients with musculoskeletal pain about the use of CFs in clinical practice. Methods: A national sample of Italian patients with musculoskeletal pain was recruited from 12 outpatient private clinics in Italy. An invitation to participate in an online survey was sent to patients: a) exhibiting musculoskeletal pain; b) aged 18-75; c) with a valid e-mail account; and d) understanding Italian language. Survey Monkey software was used to deliver the survey. The questionnaire was self-reported and included 17 questions and 2 clinical vignettes on the patients' behavior, beliefs, and attitudes towards the adoption of CFs in clinical practice. Descriptive statistics and frequencies described the actual number of respondents to each question. Results: One thousand one hundred twelve patients participated in the survey. Five hundred seventy-four participants were female (52%). The average age of patients was 41.7 ± 15.2 years. Patients defined CFs as an intervention with an unspecific effect (64.3%), but they believed in their clinical effectiveness. They identified several therapeutic effects of CFs for different health problems. Their use was considered ethically acceptable when it exerts beneficial psychological effects (60.4%), but it was banned if considered deceptive (51.1%). During clinical practice, patients wanted to be informed about the use of CFs (46.0%) that are accepted as an addition to other interventions to optimize clinical responses (39.3%). Moreover, patients explained the power of CFs through body-mind connections (37.1%). Conclusion: Patients with musculoskeletal pain had positive attitudes towards the use and effectiveness of CFs when associated with evidence-based therapy. They mostly perceived the adoption of CFs in clinical practice as ethical.

The role of hedonics in the Human Affectome

Experiencing pleasure and displeasure is a fundamental part of life. Hedonics guide behavior, affect decision-making, induce learning, and much more. As the positive and negative valence of feelings, hedonics are core processes that accompany emotion, motivation, and bodily states. Here, the affective neuroscience of pleasure and displeasure that has largely focused on the investigation of reward and pain processing, is reviewed. We describe the neurobiological systems of hedonics and factors that modulate hedonic experiences (e.g., cognition, learning, sensory input). Further, we review maladaptive and adaptive pleasure and displeasure functions in mental disorders and well-being, as well as the experience of aesthetics. As a centerpiece of the Human Affectome Project, language used to express pleasure and displeasure was also analyzed, and showed that most of these analyzed words overlap with expressions of emotions, actions, and bodily states. Our review shows that hedonics are typically investigated as processes that accompany other functions, but the mechanisms of hedonics (as core processes) have not been fully elucidated.

Neuroimaging-based biomarkers for pain: state of the field and current directions

Chronic pain is an endemic problem involving both peripheral and brain pathophysiology. Although biomarkers have revolutionized many areas of medicine, biomarkers for pain have remained controversial and relatively underdeveloped. With the realization that biomarkers can reveal pain-causing mechanisms of disease in brain circuits and in the periphery, this situation is poised to change. In particular, brain pathophysiology may be diagnosable with human brain imaging, particularly when imaging is combined with machine learning techniques designed to identify predictive measures embedded in complex data sets. In this review, we explicate the need for brain-based biomarkers for pain, some of their potential uses, and some of the most popular machine learning approaches that have been brought to bear. Then, we evaluate the current state of pain biomarkers developed with several commonly used methods, including structural magnetic resonance imaging, functional magnetic resonance imaging and electroencephalography. The field is in the early stages of biomarker development, but these complementary methodologies have already produced some encouraging predictive models that must be tested more extensively across laboratories and clinical populations.

Chronic orofacial pain, cognitive-emotional-motivational considerations: A narrative review

The following material was presented to an esteemed group of colleagues, Chinese physicians and stomotologists, friends and fellow panellists from around the globe at the Core China Conference, Nanjing China. Modern medicine accepts that a dichotomy exists between the mind, psyche and emotions and the rest of the body as if they function independently, having little downward up upward influence, one on the other. However, history teaches a different lesson. The influence of the emotional state of the patient plays a significant role effecting hormonal, neuroimmunological and peripheral modulatory factors influencing the pain experience. This brief discussion reviews the roots of modern Western Medicine in Traditional Chinese Medicine, and how we have come back to the realisation of the mind-body concept in treating the patient as a single entity and not as a collection of systems.

The impact of contextual factors on nursing outcomes and the role of placebo/nocebo effects: a discussion paper

INTRODUCTION

Placebo and nocebo effects represent one of the most fascinating topics in the health care field.

OBJECTIVES

the aims of this discussion paper were (1) to briefly introduce the placebo and nocebo effects, (2) to elucidate the contextual factors able to trigger placebo and nocebo effects in the nursing field, and (3) to debate the impact of contextual factors on nursing education, practice, organisation, and research.

METHODS

a narrative review was conducted based on the available evidence.

RESULTS

Placebo responses (from Latin "I shall please") are a beneficial outcome(s) triggered by a positive context. The opposite are the nocebo effects (from Latin "I shall harm"), which indicates an undesirable outcome(s) caused by a negative context. Both are complex and distinct psychoneurobiological phenomena in which behavioural and neurophysiological changes arise subsequent to an interaction between the patient and the health care context.

CONCLUSION

Placebo and nocebo concepts have been recently introduced in the nursing discipline, generating a wide debate on ethical issues; however, the impact on nursing education, clinical practice, nursing administration, and research regarding contextual factors triggering nocebo and placebo effects has not been debated to date.

Use of Manual Therapy for Posterior Pelvic Girdle Pain

Use of manual therapies in the treatment of posterior pelvic pain is a common practice. The rationale for use of manual therapies is often associated with the structural movement of the sacroiliac joint. Increasing evidence has shown this not to be the case, as manual therapy's effect is more neurophysiological in nature. This article seeks to clarify the difference between the two explanations as well as to expand upon outside influences such as expectations, therapeutic alliance, and equipoise that may influence the outcome of treatment. Treatment effects may be maximized with manual therapy if clinicians have an understanding of the role of each of these variables in their treatment approach.

Human resource primacy, dispositional optimism, and chest pain: A prospective, cross-lagged study of work, personality, and health

Chest pain (CP) is common, frightening, and often medically unexplained. Occupational psychological factors are associated with somatic pain. Personality may influence both perceived working conditions and somatic health, thereby confounding associations of work with health. Despite this, very few studies have investigated the interplay between work factors, personality and pain. The current study assessed relationships of a relatively novel work factor, human resource primacy (HRP), and a personality factor known to be relevant to health, dispositional optimism (Opt), with CP across two years (N = 6714). A series of structural equation models (SEMs) were fitted, modeling "substantive" and "confounded" relationships of psychological factors with CP. A "common latent factor" (CLF) was included to account for bias by unmeasured factors that may have influenced all variables (e.g. reporting bias) and the role of optimism as a possible confounder of the relationship between HRP and CP was investigated specifically. Independent effects of HRP and Opt on CP were observed. No effects of HRP/CP on Opt were observed. Opt appeared to confound the relationship between HRP and CP to some extent. However, best fit was observed for a "reciprocal" model with independent lagged effects from HRP/Opt to CP as well as from CP/Opt to HRP. Thus, results suggested a mutual causal dynamic between HRP and CP along with an influence of Opt on both HRP and CP-implying that working conditions influence the experience of chest pain while the chest pain also influences the experience of working conditions. Optimistic dispositions may influence the experience of both work and pain, but not to an extent that fully explains their relationship. Hence, the notion that associations of HRP with CP are mere artifacts of optimistic/pessimistic reporting was not supported. More likely, complex reciprocal relationships exist between these factors, in which mutual reinforcements occur and both vicious and virtuous cycles may result.

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.

Immediate effects of cervical mobilisations on global perceived effect, movement associated pain and neck kinematics in patients with non-specific neck pain. A double blind placebo randomised controlled trial

BACKGROUND

Neck pain is prevalent, costly and disabling. Cervical mobilisations are frequently used to treat it but their effectiveness has been questioned by several systematic reviews. Evidence suggests that better outcomes are achieved with mobilisations when they are applied to specific patient subgroups. A criteria for patients suitable for neck mobilisations has been proposed, but the effectiveness on this patient subgroup has not been tested.

OBJECTIVE

To assess the effectiveness of cervical mobilisations applied to a subgroup of patients with neck pain who fulfil specific criteria.

DESIGN

Randomised controlled trial.

METHOD

40 patients with neck pain attending a Physiotherapy clinic were recruited and randomised to a single session of either cervical mobilisations or motionless manual contact placebo. The immediate effects on global perceived effect, range of movement (ROM), movement velocity and movement associated pain were assessed.

RESULTS

mobilisation participants reported significantly better global perceived effect (p˂0.001) and improvements in movement associated pain (p = 0.041). Mobilisations produced a significant increase in ROM in side flexion (p = 0.006) and rotation (p = 0.044) when compared with placebo, but only in patients with pre-intervention ROM restriction. 29-47% of all movement associated pains were resolved following mobilisations and 11-27% following placebo. Patients in both groups showed a significant (p < 0.05) increase in movement velocity, but only in those who had a velocity restriction pre-intervention.

CONCLUSIONS

Cervical mobilisations are effective in improving movement-associated pain, increasing ROM and velocity, and patient perceived improvement when applied to patients with neck pain that fulfil a criteria. Their use should be advocated.

Physical therapists' perspectives on using contextual factors in clinical practice: Findings from an Italian national survey

Background

Contextual factors (CFs) represent a potential therapeutic tool to boost physiotherapy outcomes, triggering placebo effects. Nevertheless, no evidence about the use of CFs among physical therapists is currently available.

Objective

To investigate the use of CFs and the opinion of Italian physical therapists specialized in Orthopaedic Manual Therapy (OMTs) on their therapeutic benefits.

Design

An exploratory cross-sectional online survey.

Methods

A 17-item questionnaire and 2 clinical vignettes assessed the perspective of OMTs on the adoption of CFs in daily clinical practice. The target population was composed of 906 OMTs. An online survey was performed in 2016 using SurveyMonkey Software. Data were analyzed by descriptive and inferential statistics.

Results

A total of 558 volunteers (61.6% of the target OMT population) participated in the study. Half of the participants (52.0%) claimed to use CFs frequently in their practice. More of 50% of OMTs valued the therapeutic significance of CFs for different health problems as determined by a combined psychological and physiological effect. OMTs considered the use of CFs ethically acceptable when they exert beneficial therapeutic effects and their effectiveness has emerged in previous clinical experiences (30.6%). They disagreed on the adoption of CFs when they are deceptive (14.1%). Moreover, OMTs did not communicate the adoption of CFs to patients (38.2%), and CFs were usually used in addition to other interventions to optimize clinical responses (19.9%). Psychological mechanisms, patient’s expectation and conditioning were believed to be the main components behind CFs (7.9%).

Limitations

Considering that the data collected were self-reported and retrospective, recall and response biases may limit the internal and external validity of the findings.

Conclusions

OMTs used CFs in their clinical practice and believed in their therapeutic effect. The knowledge of CFs, placebo and nocebo mechanisms and their clinical effects should be included in physical therapists’ university studies.

Pain relief provided by an outgroup member enhances analgesia

Pain feels different in different social contexts, yet the mechanisms behind social pain modulation remain poorly understood. To elucidate the impact of social context on pain processing, we investigated how group membership, one of the most important social context factors, shapes pain relief behaviourally and neurally in humans undergoing functional neuroimaging. Participants repeatedly received pain relief from a member of their own group (ingroup treatment) or a member of a disliked outgroup (outgroup treatment). We observed a decrease in pain ratings and anterior insula (AI) pain responses after outgroup treatment, but not after ingroup treatment. Moreover, path analyses revealed that the outgroup treatment induced a stronger relief learning in the AI, which in turn altered pain processing, in particular if the participant entered the treatment with a negative impression toward the outgroup individual. The finding of enhanced analgesia after outgroup treatment is relevant for intergroup clinical settings. More generally, we found that group membership affects pain responses through neural learning and we thus elucidate one possible mechanism through which social context impacts pain processing.

The nocebo effect: a clinical challenge in the era of biosimilars

INTRODUCTION

The nocebo effect is defined as a negative effect of a pharmacological or non-pharmacological medical treatment that is induced by patients' expectations, and that is unrelated to the physiological action of the treatment. The nocebo effect is an important clinical challenge in the current era of biosimilars. Areas covered: This review aims to answer five key questions about the nocebo effect, namely to reveal its definition, pathophysiology, clinical relevance, contributing factors, and management. Expert commentary: The nocebo effect lowers patients' quality of life and negatively affects treatment adherence rates in biosimilar-treated patients. It may negatively impact on the cost-savings of biosimilars. Health-care providers in charge of biosimilar-treated patients need to be aware of the nocebo effect and adopt strategies to minimize it. They have to be well-informed and confident about the existing evidence about biosimilars. A good patient-physician relationship will improve patients' acceptance of biosimilars, and limits the risk of inappropriate negative bias and the nocebo effect.

Does the patients' expectations on kinesiotape affect the outcomes of patients with a rotator cuff tear? A randomized controlled clinical trial

OBJECTIVE:

To investigate the effect of setting expectations verbally on the effectiveness of kinesiotape application in patients with a rotator cuff tear.

DESIGN:

Randomized controlled, double-blind study.

SETTING:

Department of Physiotherapy and Rehabilitation.

SUBJECTS:

Eighty-nine patients with rotator cuff tear.

INTERVENTION:

Patients were randomized according to the verbal input given to patients about the effectiveness of kinesiotaping; Group 1 (there is no evidence that kinesiotaping is effective), Group 2 (there is limited evidence that kinesiotaping is effective), and Group 3 (there is evidence that kinesiotaping has an excellent effect).

MAIN MEASURES:

Resting pain, activity pain, and night pain were assessed by visual analog scale. Range of motion was assessed by a universal goniometer. Function was evaluated by the Disabilities of the Arm, Shoulder and Hand Questionnaire and the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form before and 24 hours after kinesiotape application. Only resting pain and activity pain were assessed after 30 minutes.

RESULTS:

There were no statistically significant differences (ANOVA) between any groups at the three assessment points. The intragroup assessment showed that in Group 2, only resting pain after 30 minutes improved (3.2 ± 2.9 to 2.6 ± 2.8; P  = 0.02 ). An improvement in resting pain both after 30 minutes and after 24 hours was found in the third group (4.1 ± 2.4 to 2.3 ± 2.3, P  = 0.001; 4.1 ± 2.4 to 2.2 ± 2.3, P  = 0.001, respectively). Activity pain and night pain were improved in all groups after 24 hours.

CONCLUSION:

Setting positive expectations verbally about kinesiotaping might be effective in reducing pain in patients with rotator cuff tear.

Contextual modulation of autonomic pain reactivity

Although modulation of cardiac activity may be influenced by several factors, interaction between autonomic nociceptive responses and the high-level of cortical processes is not clearly understood. Here, we studied in 26 subjects whether empathetic or unempathetic contexts could interact with autonomic pain responses. RR intervals variability was used to approach parasympathetic and sympathetic responses to painful thermal stimulations, according to contexts evoked by experimenters' comments. We observed that unempathetic context increased sympathetic reactivity to comments and to painful stimulations without any parasympathetic change. These results show an interaction between context and nociceptive processes in cardiovascular control.

Clinical relevance of contextual factors as triggers of placebo and nocebo effects in musculoskeletal pain

Placebo and nocebo effects are embodied psycho-neurobiological responses capable of modulating pain and producing changes at different neurobiological, body at perceptual and cognitive levels. These modifications are triggered by different contextual factors (CFs) presented in the therapeutic encounter between patient and healthcare providers, such as healing rituals and signs. The CFs directly impact on the quality of the therapeutic outcome: a positive context, that is a context characterized by the presence of positive CFs, can reduce pain by producing placebo effects, while a negative context, characterized by the presence of negative CFs, can aggravate pain by creating nocebo effects. Despite the increasing interest about this topic; the detailed study of CFs as triggers of placebo and nocebo effects is still lacked in the management of musculoskeletal pain.

Increasing evidence suggest a relevant role of CFs in musculoskeletal pain management. CFs are a complex sets of internal, external or relational elements encompassing: patient’s expectation, history, baseline characteristics; clinician’s behavior, belief, verbal suggestions and therapeutic touch; positive therapeutic encounter, patient-centered approach and social learning; overt therapy, posology of intervention, modality of treatment administration; marketing features of treatment and health care setting. Different explanatory models such as classical conditioning and expectancy can explain how CFs trigger placebo and nocebo effects. CFs act through specific neural networks and neurotransmitters that were described as mediators of placebo and nocebo effects.

Available findings suggest a relevant clinical role and impact of CFs. They should be integrated in the clinical reasoning to increase the number of treatment solutions, boosts their efficacy and improve the quality of the decision-making. From a clinical perspective, the mindful manipulation of CFs represents a useful opportunity to enrich a well-established therapy in therapeutic setting within the ethical border. From a translational perspective, there is a strong need of research studies on CFs close to routine and real-world clinical practice in order to underline the uncertainty of therapy action and help clinicians to implement knowledge in daily practice.

Visual reminders of death enhance nociceptive-related cortical responses and event-related alpha desynchronisation

Previous research suggests that prompting individuals to think on their own mortality affects their perception of painful somatic stimuli and related brain activity. Grounded on the assumption that reminders of mortality may recruit threat-defence mechanisms similar to the ones activated by painful nociceptive stimuli, we hypothesize that the effects exerted by linguistic reminders of death on pain perception and brain activity would be elicited by passive observation of death-related pictures vs. more generic threat-related pictures. Results showed an increase of the laser evoked P2 amplitude and oscillatory theta activity when participants observed death-related images. However, no change in pain ratings was found. Moreover, observation of death-related content was linked to increased oscillatory alpha desynchronisation but not to variations of visual evoked potentials amplitude. Our findings indicate that pairing potentially noxious stimuli with death-related images exerts a preferential modulation of nociceptive and visual cortical representations.