48 THE MAGNITUDE OF PLACEBO EFFECTS IN RELATION TO EXPERIMENTAL PAIN AND CHRONIC PAIN CONDITIONS

2010 ◽  
Vol 4 (S1) ◽  
pp. 15-15
Author(s):  
L. Vase
Keyword(s):  
Chronic Pain ◽  
Experimental Pain ◽  
Placebo Effects ◽  
Chronic Pain Conditions

scholarly journals Experimentally induced pain does not influence updating of peripersonal space and body representations following tool-use

2018 ◽  
Author(s):  
Axel Davies Vittersø ◽  
Monika Halicka ◽  
Gavin Buckingham ◽  
Michael J Proulx ◽  
Mark Wilson ◽  
...  
Keyword(s):  
Chronic Pain ◽  
Tool Use ◽  
Experimental Pain ◽  
Peripersonal Space ◽  
The Body ◽  
Body Representations ◽  
Tactile Target ◽  
The Difference ◽  
Chronic Pain Conditions ◽  
Crossmodal Congruency

Representations of the body and peripersonal space can be distorted for people with some chronic pain conditions. Experimental pain induction can give rise to similar, but transient distortions in healthy individuals. However, spatial and bodily representations are dynamic, and constantly update as we interact with objects in our environment. It is unclear whether induced pain disrupts the mechanisms involved in updating these representations. In the present study, we sought to investigate the effect of induced pain on the updating of peripersonal space and body representations during and following tool-use. We compared performance under three conditions (pain, active placebo, neutral) on a visuotactile crossmodal congruency task and a tactile distance judgement task to measure updating of peripersonal space and body representations, respectively. We induced pain by applying 1% capsaicin cream to the arm, and for placebo we used a gel that induced non-painful warming. Consistent with previous findings, the difference in crossmodal interference from visual distractors in the same compared to opposite visual field to the tactile target was less when tools were crossed than uncrossed. This suggests an extension of peripersonal space to incorporate the tips of the tools. Also consistent with previous findings, estimates of the felt distance between two points (tactile distance judgements) decreased after active tool-use. In contrast to our predictions, however, we found no evidence that pain interfered with performance on either task when compared to the control conditions. This suggests that the updating of peripersonal space and body representations is not disrupted by induced pain. Therefore, acute pain does not account for the distorted representations of the body and peripersonal space that can endure in people with chronic pain conditions.

scholarly journals The effects of propranolol on heart rate variability and quantitative, mechanistic, pain profiling: a randomized placebo-controlled crossover study

2018 ◽  
Vol 18 (3) ◽  
pp. 479-489 ◽  
Author(s):  
Kristian Kjær Petersen ◽  
Hjalte Holm Andersen ◽  
Masato Tsukamoto ◽  
Lincoln Tracy ◽  
Julian Koenig ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Chronic Pain ◽  
Pain Sensitivity ◽  
Experimental Pain ◽  
Central Pain ◽  
Healthy Male ◽  
Pain Pathways ◽  
Β Blocker ◽  
Chronic Pain Conditions

AbstractBackground and aimsThe autonomic nervous system (ANS) is capable of modulating pain. Aberrations in heart rate variability (HRV), reflective of ANS activity, are associated with experimental pain sensitivity, chronic pain, and more recently, pain modulatory mechanisms but the underlying mechanisms are still unclear. HRV is lowered during experimental pain as well as in chronic pain conditions and HRV can be increased by propranolol, which is a non-selective β-blocker. Sensitization of central pain pathways have been observed in several chronic pain conditions and human mechanistic pain biomarkers for these central pain pathways include temporal summation of pain (TSP) and conditioned pain modulation (CPM). The current study aimed to investigate the effect of the β-blocker propranolol, and subsequently assessing the response to standardized, quantitative, mechanistic pain biomarkers.MethodsIn this placebo-controlled, double-blinded, randomized crossover study, 25 healthy male volunteers (mean age 25.6 years) were randomized to receive 40 mg propranolol and 40 mg placebo. Heart rate, blood pressure, and HRV were assessed before and during experimental pain tests. Cuff pressure pain stimulation was used for assessment of pain detection (cPDTs) and pain tolerance (cPTTs) thresholds, TSP, and CPM. Offset analgesia (OA) was assessed using heat stimulation.ResultsPropranolol significantly reduced heart rate (p<0.001), blood pressure (p<0.02) and increased HRV (p<0.01) compared with placebo. No significant differences were found comparing cPDT (p>0.70), cPTT (p>0.93), TSP (p>0.70), OA-effect (p>0.87) or CPM (p>0.65) between propranolol and placebo.ConclusionsThe current study demonstrated that propranolol increased HRV, but did not affect pressure pain sensitivity or any pain facilitatory or modulatory outcomes.ImplicationsAnalgesic effects of propranolol have been reported in clinical pain populations and the results from the current study could indicate that increased HRV from propranolol is not associated with peripheral and central pain pathways in healthy male subjects.

scholarly journals Neural Mechanisms of Temporomandibular Joint and Masticatory Muscle Pain: A Possible Role for Peripheral Glutamate Receptor Mechanisms

2005 ◽  
Vol 10 (3) ◽  
pp. 145-152 ◽  
Author(s):  
David K Lam ◽  
Barry J Sessle ◽  
Brian E Cairns ◽  
James W Hu
Keyword(s):  
Chronic Pain ◽  
Glutamate Receptors ◽  
Temporomandibular Joint ◽  
Temporomandibular Disorders ◽  
Muscle Pain ◽  
Neuronal Excitability ◽  
Experimental Pain ◽  
Ionotropic Glutamate Receptors ◽  
Peripheral Tissues ◽  
Chronic Pain Conditions

The purpose of the present review is to correlate recent knowledge of the role of peripheral ionotropic glutamate receptors in the temporomandibular joint and muscle pain from animal and human experimental pain models with findings in patients. Chronic pain is common, and many people suffer from chronic pain conditions involving deep craniofacial tissues such as temporomandibular disorders or fibromyalgia. Animal and human studies have indicated that the activation of peripheral ionotropic glutamate receptors in deep craniofacial tissues may contribute to muscle and temporomandibular joint pain and that sex differences in the activation of glutamate receptors may be involved in the female predominance in temporomandibular disorders and fibromyalgia. A peripheral mechanism involving autocrine and/or paracrine regulation of nociceptive neuronal excitability via injury or inflammation-induced release of glutamate into peripheral tissues that may contribute to the development of craniofacial pain is proposed.

REPRINTED WITH PERMISSION OF IASP – PAIN 160 (2019) 2679–2690: Conditioned pain modulation as a biomarker of chronic pain: a systematic review of its concurrent validity

Ból ◽  
2020 ◽  
Vol 21 (3) ◽  
pp. 1-15
Author(s):  
Carina Fernandes ◽  
Marina Pidal-Miranda ◽  
Noelia Samartin-Veiga ◽  
María T. Carrillo-de-la-Peña
Keyword(s):  
Systematic Review ◽  
Chronic Pain ◽  
Concurrent Validity ◽  
Clinical Symptoms ◽  
Clinical Manifestations ◽  
Experimental Pain ◽  
Pain Modulation ◽  
Conditioned Pain Modulation ◽  
Pain Mechanisms ◽  
Chronic Pain Conditions

Conditioned pain modulation (CPM) is a promising psychophysical biomarker of central pain mechanisms because it significantly discriminates patients with chronic pain from healthy controls. Nevertheless, it is unclear in what extent CPM assessed experimentally is correlated with clinical manifestations of pain. To assess the concurrent validity of CPM, we performed a systematic review of the literature reporting correlations between CPM responses and pain intensity, disability, duration, and area in patients with different chronic pain conditions. We included 32 studies that altogether encompassed data from 1958 patients and provided 62 correlations. The majority of the results (69%) reported nonsignificant correlations between CPM efficiency and clinical manifestations of pain, whereas the remaining results showed a correlation between CPM reduction and worse clinical symptoms of pain. The modality of stimulation, the type of pain, and the stimulation site appear to be critical variables that influenced the pattern of results. Given that most of the studies were conducted with highly heterogeneous methodologies and unclear risk of bias, the findings highlight the need for future studies using standardized measures of clinical and experimental pain before considering CPM as a valid biomarker of pain. We discuss some guidelines to overcome the constraints in this promising line of research.

Placebo and Nocebo Effects in Chronic Pain Patients

2014 ◽  
Vol 222 (3) ◽  
pp. 135-139 ◽  
Author(s):  
Lene Vase ◽  
Ina Skyt ◽  
Gitte Laue Petersen ◽  
Donald D. Price
Keyword(s):  
Chronic Pain ◽  
Pain Relief ◽  
Healthy Volunteers ◽  
Experimental Pain ◽  
Clinical Treatment ◽  
Placebo Effects ◽  
Chronic Pain Patients ◽  
Nocebo Effects ◽  
Patients Experience ◽  
Pain Patients

Placebo, as well as nocebo, effects have been primarily investigated in studies with healthy volunteers exposed to acute experimental pain. Yet with regard to chronic pain patients, there is emerging evidence for significant placebo effects but not for nocebo effects. Expectations of pain relief are known to contribute to placebo effects, and lately the influence of emotional feelings has also been investigated. In this line of research, an experiential method has been applied to capture the emotional feelings that chronic pain patients experience during placebo and nocebo interventions. The findings indicate that the patients’ expectations of treatment effects are highly embedded in their emotional feelings. Hence, in order to optimize placebo factors in the clinical treatment of patients, it may be pivotal to investigate and enhance both expectancies and emotional feelings about treatments.

scholarly journals Placebo effects in chronic pain conditions. Can placebo components enhance the efficacy of active treatments?

2016 ◽  
Vol 12 (23) ◽  
Author(s):  
Ina Skyt ◽  
Lene Vase
Keyword(s):  
Chronic Pain ◽  
Clinical Practice ◽  
Healthy Volunteers ◽  
Placebo Effect ◽  
Brain Activation ◽  
Review Literature ◽  
Endogenous Opioids ◽  
Placebo Effects ◽  
Placebo Analgesia ◽  
Chronic Pain Conditions

The conceptualization of the placebo phenomenon has changed. Previously placebo was seen as an inactive agent, but today placebo effects are viewed as related to patients’ perception of a treatment. During the last decades, the mechanisms underlying placebo analgesia effects have been specified and it has been shown that patients’ perception of a treatment is influenced by previous experiences, the patient-practitioner relationship as well as expectations and emotions. These factors are, in turn, associated with altered brain activation and release of endogenous opioids, thereby demonstrating that placebo analgesia has a psycho-neurobiological basis. The placebo effect has primarily been investigated in relation to healthy volunteers, but here we review literature on placebo mechanisms in relation to chronic pain states as this is important for an understanding of how placebo factors can be optimized in clinical practice. We outline some of the ethical discussions concerning the use of placebo in clinical practice and we illustrate how patients perception of a treatment contribute to the efficacy of active treatments, thereby showing how focus on patients perception of a treatment may help optimize the outcome of standard active pain treatments in ethically appropriate ways.

Retrospective analysis on the effect of spinal cord stimulation on opioid consumption

2020 ◽  
Author(s):  
Awinita Barpujari ◽  
Michael A Erdek
Keyword(s):  
Spinal Cord ◽  
Chronic Pain ◽  
Retrospective Analysis ◽  
Spinal Cord Stimulation ◽  
Alternative Therapy ◽  
Opioid Consumption ◽  
Opioid Use ◽  
Number Of Patients ◽  
Chronic Pain Conditions ◽  
Post Trial

Aim: Spinal cord stimulation (SCS) is used to clinically manage and/or treat several chronic pain etiologies. A limited amount is known about the influence on patients' use of opioid pain medication. This retrospective analysis evaluated SCS effect on opioid consumption in patients presenting with chronic pain conditions. Materials & methods: Sixty-seven patients underwent a temporary trial device, permanent implant or both. Patients were divided for assessment based on the nature of their procedure(s). Primary outcome was change in morphine equivalent dose (MED), ascertained from preoperative and postoperative medication reports. Results: Postoperative MED was significantly lower in patients who received some form of neuromodulation therapy. Pretrial patients reported an average MED of 41.01 ± 10.23 mg per day while post-trial patients reported an average of 13.30 ± 5.34 mg per day (p < 0.001). Pre-implant patients reported an average MED of 39.14 ± 13.52 mg per day while post-implant patients reported an average MED of 20.23 ± 9.01 mg per day (p < 0.001). There were no significant differences between pre-trial and pre-implant MED, nor between post-trial and post-implant MED. Of the 42 study subjects who reported some amount of pre-intervention opioid use, 78.57% indicated a lower MED (n = 33; p < 0.001), 16.67% indicated no change (n = 7) and 4.76% (n = 2) indicated a higher MED, following intervention. Moreover, SCS therapy resulted in a 26.83% reduction (p < 0.001) in the number of patients with MED >50 mg per day. Conclusion: Spinal cord stimulation may reduce opioid use when implemented appropriately. Neuromodulation may represent alternative therapy for alleviating chronic pain which may avoid a number of deleterious side effects commonly associated with opioid consumption.

scholarly journals Central sensitisation in chronic pain conditions: latest discoveries and their potential for precision medicine

2021 ◽  
Vol 3 (5) ◽  
pp. e383-e392
Author(s):  
Jo Nijs ◽  
Steven Z George ◽  
Daniel J Clauw ◽  
César Fernández-de-las-Peñas ◽  
Eva Kosek ◽  
...  
Keyword(s):  
Chronic Pain ◽  
Precision Medicine ◽  
Central Sensitisation ◽  
Chronic Pain Conditions
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