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O'Malley CA, Smith SA, Mauger AR, Norbury R. Exercise-induced pain within endurance exercise settings: Definitions, measurement, mechanisms and potential interventions. Exp Physiol 2024. [PMID: 38985528 DOI: 10.1113/ep091687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Accepted: 06/18/2024] [Indexed: 07/12/2024]
Abstract
Pain can be defined as an unpleasant sensory and emotional experience associated with or resembling that associated with actual or potential tissue damage. Though consistent with this definition, different types of pain result in different behavioural and psychophysiological responses. For example, the transient, non-threatening, acute muscle pain element of exercise-induced pain (EIP) is entirely different from other pain types like delayed onset muscle soreness, muscular injury or chronic pain. However, studies often conflate the definitions or assume parity between distinct pain types. Consequently, the mechanisms through which pain might impact exercise behaviour across different pain subcategories may be incorrectly assumed, which could lead to interventions or recommendations that are inappropriate. Therefore, this review aims to distinguish EIP from other subcategories of pain according to their aetiologies and characteristics, thereby providing an updated conceptual and operational definition of EIP. Secondly, the review will discuss the experimental pain models currently used across several research domains and their relevance to EIP with a focus on the neuro-psychophysiological mechanisms of EIP and its effect on exercise behaviour and performance. Finally, the review will examine potential interventions to cope with the impact of EIP and support wider exercise benefits. HIGHLIGHTS: What is the topic of this review? Considerations for future research focusing on exercise-induced pain within endurance exercise settings. What advances does it highlight? An updated appraisal and guide of research concerning exercise-induced pain and its impact on endurance task behaviour, particularly with reference to the aetiology, measurement, and manipulation of exercise-induced pain.
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Affiliation(s)
- Callum A O'Malley
- School of Sport, Exercise, and Nutritional Sciences, University of Exeter, Exeter, UK
| | - Samuel A Smith
- School of Sport and Exercise Sciences, University of Kent, Canterbury, UK
| | - Alexis R Mauger
- School of Sport and Exercise Sciences, University of Kent, Canterbury, UK
| | - Ryan Norbury
- Faculty of Sport, Technology, and Health Sciences, St Mary's University, Twickenham, UK
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2
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Intelangelo L, Mista CA, Barone M, Imaz F, Laugero SJ, Adur J, Andersen OK, Biurrun Manresa JA. Spatiotemporal characterization of an experimental model of muscle pain in humans based on short-wave diathermy. Eur J Pain 2024. [PMID: 38980214 DOI: 10.1002/ejp.2309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 06/11/2024] [Accepted: 06/19/2024] [Indexed: 07/10/2024]
Abstract
BACKGROUND Commonly used models for eliciting muscle pain involve the injection of algesic substances or the induction of delayed onset muscle soreness. The former require invasive procedures, and the time frame for pain induction and subsidence in the latter can be inconvenient. This study presents a detailed spatiotemporal characterization of a new experimental model of muscle pain based on short-wave diathermy (SWD), developed to overcome the limitations of existing models. METHODS The shoulder was selected as target site and the effects of the model were tested in two sessions to assess its reliability. Pain intensity profiles were recorded during the application of SWD, and changes in pressure pain threshold (PPT) in the infraspinatus muscle, together with pain intensity, duration, and quality were assessed 30 min after induction. RESULTS SWD-induced pain intensity scores averaged 4 points on a visual analogue scale, whereas PPT showed a consistent decrease of about 25% relative to baseline values. Pain was localized in the shoulder area, and was described as continuous, dull, well-delimited, heavy, and bearable. Pain lasted for an average of 145 min without requiring reinduction and was reliably elicited in both experimental sessions. CONCLUSION SWD can be used to elicit experimental muscle pain in a non-invasive, long-lasting, and reliable way and allows for repeated within- and between-session testing in the shoulder. SIGNIFICANCE STATEMENT SWD produces deep heating in muscles by converting electromagnetic energy to thermal energy. It was previously shown that it can be used to elicit experimental pain in the forearm muscles, and the present study demonstrates that this can be reliably generalized to other body sites, such as the shoulder. Furthermore, SWD application is non-invasive and presents a convenient time frame for pain induction and subsidence, thus overcoming limitations associated with traditional muscle pain models.
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Affiliation(s)
- Leonardo Intelangelo
- University Center for Assistance, Teaching and Research (CUADI), University of Gran Rosario, Rosario, Argentina
| | - Christian Ariel Mista
- Institute for Research and Development on Bioengineering and Bioinformatics (IBB), CONICET-UNER, Oro Verde, Argentina
- Center for Rehabilitation Engineering and Neuromuscular and Sensory Research (CIRINS), National University of Entre Ríos (UNER), Oro Verde, Argentina
| | - Mauro Barone
- University Center for Assistance, Teaching and Research (CUADI), University of Gran Rosario, Rosario, Argentina
| | - Fernando Imaz
- University Center for Assistance, Teaching and Research (CUADI), University of Gran Rosario, Rosario, Argentina
| | - Silvio Jorge Laugero
- Laboratory of Electromagnetic Fields in Biomedical Applications (LACEMAB), National University of Entre Ríos (UNER), Oro Verde, Argentina
| | - Javier Adur
- Institute for Research and Development on Bioengineering and Bioinformatics (IBB), CONICET-UNER, Oro Verde, Argentina
- Laboratory of Electromagnetic Fields in Biomedical Applications (LACEMAB), National University of Entre Ríos (UNER), Oro Verde, Argentina
| | - Ole Kæseler Andersen
- Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Faculty of Medicine, Aalborg University (AAU), Aalborg, Denmark
| | - José Alberto Biurrun Manresa
- Institute for Research and Development on Bioengineering and Bioinformatics (IBB), CONICET-UNER, Oro Verde, Argentina
- Center for Rehabilitation Engineering and Neuromuscular and Sensory Research (CIRINS), National University of Entre Ríos (UNER), Oro Verde, Argentina
- Laboratory of Electromagnetic Fields in Biomedical Applications (LACEMAB), National University of Entre Ríos (UNER), Oro Verde, Argentina
- Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Faculty of Medicine, Aalborg University (AAU), Aalborg, Denmark
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Lou W, Li X, Jin R, Peng W. Time-varying phase synchronization of resting-state functional magnetic resonance imaging reveals a shift toward self-referential processes during sustained pain. Pain 2024; 165:1493-1504. [PMID: 38193830 DOI: 10.1097/j.pain.0000000000003152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 11/20/2023] [Indexed: 01/10/2024]
Abstract
ABSTRACT Growing evidence has suggested that time-varying functional connectivity between different brain regions might underlie the dynamic experience of pain. This study used a novel, data-driven framework to characterize the dynamic interactions of large-scale brain networks during sustained pain by estimating recurrent patterns of phase-synchronization. Resting-state functional magnetic resonance imaging signals were collected from 50 healthy participants before (once) and after (twice) the onset of sustained pain that was induced by topical application of capsaicin cream. We first decoded the instantaneous phase of neural activity and then applied leading eigenvector dynamic analysis on the time-varying phase-synchronization. We identified 3 recurrent brain states that show distinctive phase-synchronization. The presence of state 1, characterized by phase-synchronization between the default mode network and auditory, visual, and sensorimotor networks, together with transitions towards this brain state, increased during sustained pain. These changes can account for the perceived pain intensity and reported unpleasantness induced by capsaicin application. In contrast, state 3, characterized by phase-synchronization between the cognitive control network and sensory networks, decreased after the onset of sustained pain. These results are indicative of a shift toward internally directed self-referential processes (state 1) and away from externally directed cognitive control processes (state 3) during sustained pain.
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Affiliation(s)
- Wutao Lou
- Department of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong, China
| | - Xiaoyun Li
- School of Psychology, Shenzhen University, Shenzhen, Guangdong, China
| | - Richu Jin
- Research Institute of Trustworthy Autonomous Systems, Southern University of Science and Technology, Shenzhen, China
- Department of Computer Science and Engineering, Southern University of Science and Technology, Shenzhen, China
| | - Weiwei Peng
- School of Psychology, Shenzhen University, Shenzhen, Guangdong, China
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Tewari D, Bawari S, Sah AN, Sharma H, Joshi BC, Gupta P, Sharma VK. Himalayan Pyracantha crenulata (D.Don) M.Roem. leaf and fruit extracts alleviate algesia through COX-2 and Mu-opioid receptor mediated pathways. JOURNAL OF ETHNOPHARMACOLOGY 2024; 318:117004. [PMID: 37544342 DOI: 10.1016/j.jep.2023.117004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 07/30/2023] [Accepted: 08/02/2023] [Indexed: 08/08/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Pyracantha crenulata (D.Don) M.Roem., a plant of high nutritional and medicinal value is traditionally employed for its analgesic property in joint and body pain in the Kumaun region of Western Himalaya. AIM OF THE STUDY To validate the traditional claims for analgesic property of Pyracantha crenulata. METHODS Hydroethanolic extract of P. crenulata leaves and fruits were tested for their analgesic potential in rodent models for algesia by tail immersion test, tail flick test, Eddy's hot plate model, and formalin induced paw irritation test in Wistar rats. Molecular docking and dynamics studies were also performed to understand the possible mechanisms. RESULTS Both P. crenulata fruit extract and leaf extract exhibited significant amelioration in all the tested experimental models of algesia acting through central and peripheral mechanisms. The efficacy in reducing nociception was found comparable to diclofenac that was used as a reference standard. Molecular docking and dynamic simulation studies further established binding affinity of gallic acid (confirmed to be present in P. crenulata leaf extract through HPTLC profiling) with cyclooxygenase-2 (COX-2) and mu-opioid receptors, suggesting the modulatory effect of these extracts on COX-2 and mu-opioid receptors in combating algesia. CONCLUSION P. crenulata extracts produce analgesic effects plausibly through COX-2 and mu-opioid receptor mediated pathways.
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Affiliation(s)
- Devesh Tewari
- Department of Pharmacognosy and Phytochemistry, School of Pharmaceutical Sciences, Delhi Pharmaceutical Sciences and Research University (DPSRU), New Delhi, 110017, India.
| | - Sweta Bawari
- Amity Institute of Pharmacy, Amity University Campus, Sector-125, Noida, 201301, Gautam Buddha Nagar, Uttar Pradesh, India
| | - Archana N Sah
- Department of Pharmaceutical Sciences, Faculty of Technology, Sir J.C. Bose Technical Campus, Bhimtal, Kumaun University, Nainital, 263136, Uttarakhand, India
| | - Himanshu Sharma
- Central Ayurveda Research Institute Under CCRAS, Gwalior Road, Jhansi, India
| | - Bhuwan Chandra Joshi
- Department of Pharmaceutical Sciences, Faculty of Technology, Sir J.C. Bose Technical Campus, Bhimtal, Kumaun University, Nainital, 263136, Uttarakhand, India
| | - Pawan Gupta
- Department of Pharmaceutical Chemistry, Shri Vile Parle Kelavani Mandal's Institute of Pharmacy, Dhule, Maharashtra, India.
| | - Vishnu K Sharma
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research (NIPER), Mohali, Punjab, 160062, India.
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Smith SA, Norbury R, Hunt AJ, Mauger AR. Intra- and interindividual reliability of muscle pain induced by an intramuscular injection of hypertonic saline injection into the quadriceps. Eur J Pain 2023; 27:1216-1225. [PMID: 37376739 DOI: 10.1002/ejp.2151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 05/05/2023] [Accepted: 06/11/2023] [Indexed: 06/29/2023]
Abstract
BACKGROUND Intramuscular injections of hypertonic saline are commonly used to induce experimental muscle pain, but reliability data on this technique are lacking. This study investigated the intra- and interindividual reliability of pain measures from a hypertonic saline injection into the vastus lateralis. METHODS Fourteen healthy participants (6 female) attended three laboratory visits where they received an intramuscular injection of 1 mL hypertonic saline into the vastus lateralis. Changes in pain intensity were recorded on an electronic visual analogue scale, and pain quality was assessed after pain had resolved. Reliability was assessed with the coefficient of variation (CV), minimum detectable change (MDC) and intraclass correlation coefficient (ICC) with 95% CIs. RESULTS Mean pain intensity displayed high levels of intraindividual variability (CV = 16.3 [10.5-22.0]%) and 'poor' to 'very good' relative reliability (ICC = 0.71 [0.45-0.88]) but had a MDC of 11 [8-16] au (out of 100). Peak pain intensity exhibited high levels of intraindividual variability (CV = 14.8 [8.8-20.8]%) with 'moderate' to 'excellent' levels of relative reliability (ICC = 0.81 [0.62-0.92]), whereas the MDC was 18 [14-26] au. Measures of pain quality exhibited good reliability. Interindividual variability in pain measures was high (CV > 37%). CONCLUSIONS Intramuscular injections of 1 mL of hypertonic saline into the vastus lateralis display substantial levels of interindividual variability, but MDC is below the clinically important changes in pain. This model of experimental pain is suitable for studies involving repeated exposures. SIGNIFICANCE Many pain research studies have performed intramuscular injections of hypertonic saline to investigate responses to muscle pain. However, the reliability of this technique is not well established. We examined the pain response over three repeated sessions of a hypertonic saline injection. The pain induced by hypertonic saline has considerable interindividual variability but has largely acceptable intraindividual reliability. Therefore, the injections of hypertonic saline to induce muscle pain are a reliable model of experimental muscle pain.
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Affiliation(s)
- Samuel A Smith
- School of Sport and Exercise Sciences, University of Kent, Canterbury, UK
| | - Ryan Norbury
- School of Sport and Exercise Sciences, University of Kent, Canterbury, UK
- Faculty of Sport, Allied Health, and Performance Science, St Mary's University, Twickenham, UK
| | - Adam J Hunt
- School of Sport and Exercise Sciences, University of Kent, Canterbury, UK
| | - Alexis R Mauger
- School of Sport and Exercise Sciences, University of Kent, Canterbury, UK
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Li X, Lou W, Zhang W, Tong RKY, Hu L, Peng W. Ongoing first-hand pain facilitates somatosensory resonance but inhibits affective sharing in empathy for pain. Neuroimage 2022; 263:119599. [PMID: 36049698 DOI: 10.1016/j.neuroimage.2022.119599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 08/05/2022] [Accepted: 08/28/2022] [Indexed: 10/31/2022] Open
Abstract
Alterations of empathy for others' pain among patients with chronic pain remained inconsistent. Here, applying a capsaicin-based ongoing pain model on healthy participants, this study investigated how ongoing first-hand pain influences empathic reactions to vicarious pain stimuli. Healthy participants were randomly treated with topical capsaicin cream (capsaicin group) or hand cream (control group) on the left forearm. Video clips showing limbs in painful and non-painful situations were used to induce empathic responses. The capsaicin group showed greater empathic neural responses in the right primary somatosensory cortex (S1) than the control group but smaller responses in the left anterior insula (AI) accompanied with smaller empathic pain-intensity ratings. Notably, the intensity of ongoing pain negatively correlated with empathy-related neural responses in the left AI. Inter-subject phase synchronization analysis was used to assess stimulus-dependent dynamic functional connectivity within or between brain regions engaged in pain empathy. The capsaicin group showed greater empathy-related neural synchronization within S1 and between S1 and AI, but less synchronization within AI and between AI and MCC. Behaviorally, the differential inter-subject pain-intensity rating alignment between painful and non-painful videos was more positive for the capsaicin group than for the control group, and this effect was partially mediated by the inter-subject neural synchronization between S1 and AI. These results suggest that ongoing first-hand pain facilitates neural activation and synchronization within brain regions associated with empathy-related somatosensory resonance at the cost of inhibiting activation and synchronization within brain regions engaged in empathy-related affective sharing.
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Affiliation(s)
- Xiaoyun Li
- School of Psychology, Shenzhen University, Shenzhen, China
| | - Wutao Lou
- Department of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong, China
| | - Wenyun Zhang
- School of Psychology, Shenzhen University, Shenzhen, China
| | - Raymond Kai-Yu Tong
- Department of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong, China
| | - Li Hu
- CAS Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China; Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Weiwei Peng
- School of Psychology, Shenzhen University, Shenzhen, China.
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7
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Efstathiou MA, Giannaki CD, Roupa Z, Hadjisavvas S, Stefanakis M. Evidence of distorted proprioception and postural control in studies of experimentally induced pain: a critical review of the literature. Scand J Pain 2022; 22:445-456. [PMID: 35470647 DOI: 10.1515/sjpain-2021-0205] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 03/23/2022] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Deficits in proprioception and postural control are common in patients with different musculoskeletal pain syndromes. It has been proposed that pain can negatively affect proprioception and postural control at a peripheral level, however research is limited to animal studies. Human studies have shown that it is more likely, that the link between pain and proprioceptive deficits, lies within changes in the central nervous system where noxious and non-noxious stimuli may overlap. In clinical studies, causality cannot be determined due to other factors which could confound the assessment such as pathophysiological features of the underlying musculoskeletal disorder and different psycho-social influences especially in patients with chronic pain. On the other hand, experimentally induced pain in healthy participants is able to control most of these confounding factors and perhaps offers an assessment of the effects of pain on proprioception and postural control. The aim of this paper is to critically appraise the literature related to the effect of experimentally induced pain on proprioception and postural control. Results from these studies are discussed and limitations are highlighted for future research. METHODS A search of databases (Medline, Scopus, PubMed) was conducted as well as reference check from relevant articles published since 2000. Fifteen studies which explored the effect of experimentally induced pain on postural control and ten studies which explored the effect of experimentally induced pain on proprioception were included. RESULTS We found that in the majority of the studies, postural control was negatively affected by experimentally induced pain. Results for proprioception were mixed depending on the body region and the way the painful stimuli were delivered. Kinesthesia was negatively affected in two studies, while in one study kinesthesia was enhanced. Joint position sense was not affected in four out of five studies. Finally, force sense was affected in three out of four studies. CONCLUSIONS From a clinical point of view, findings from the available literature suggest that experimentally induced pain impairs postural control and could potentially increases the risk for falls in patients. Interventions aiming to reduce pain in these patients could lead to preservation or improvement of their balance. On the other hand, the same conclusion cannot be drawn for the effect of experimentally induced pain on kinesthesia and joint position sense due to the limited number of studies showing such an effect.
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Affiliation(s)
| | | | - Zoe Roupa
- Department of Life and Health Sciences, University of Nicosia, Nicosia, Cyprus
| | - Stelios Hadjisavvas
- Department of Life and Health Sciences, University of Nicosia, Nicosia, Cyprus
| | - Manos Stefanakis
- Department of Life and Health Sciences, University of Nicosia, Nicosia, Cyprus
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Sandbach PJ, Carvajal MS, Uygur M, Dankel SJ. The impact of post-exercise blood flow restriction on local muscle endurance of a remote limb. Clin Physiol Funct Imaging 2022; 42:356-361. [PMID: 35778804 DOI: 10.1111/cpf.12776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 06/30/2022] [Indexed: 11/29/2022]
Abstract
BACKGROUND Studies have examined the influence of post-exercise blood flow restriction as a mechanism to activate muscle afferents and assess non-local muscle fatigue. While these studies have assessed fatigue during maximal contractions, less is known on how these afferents may impact submaximal local muscle endurance which was the purpose of the present study. METHODS Individuals completed two testing visits which involved completing a set of elbow flexion exercises to volitional failure on the non-dominant followed by the dominant arm. During both trials, a pneumatic cuff was placed at the top of the non-dominant arm prior to exercise. This cuff was inflated to either 0% (control) or 70% (experimental) of the individual's arterial occlusion pressure immediately after the set was completed. We then evaluated how this impacted local muscle endurance of the dominant arm using a Bayesian paired samples t-test with an uninformed prior width of 0.707 centered on 0. RESULTS A total of 36 individuals completed the study (18 females). There was a greater discomfort present in the experimental trial when compared to the control trial [control: 4.5 (SD: 2.4), experimental: 5.8 (SD: 1.9); BF10 =61.46], but there were no differences in repetitions completed on the dominant arm [control: 43 (SD: 9), experimental: 43 (SD: 10); BF10 = 0.179]. CONCLUSION Applying blood flow restriction post-exercise induced sensations of discomfort but did not alter local muscle endurance of the contralateral limb. These results suggest that increasing the activation of muscle afferents does not appear to alter submaximal muscle endurance of a remote limb. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Paul J Sandbach
- Department of Health and Exercise Science, Exercise Physiology Laboratory, Rowan University, Glassboro, NJ, USA
| | - Marlon S Carvajal
- Department of Health and Exercise Science, Exercise Physiology Laboratory, Rowan University, Glassboro, NJ, USA
| | - Mehmet Uygur
- Department of Health and Exercise Science, Exercise Physiology Laboratory, Rowan University, Glassboro, NJ, USA
| | - Scott J Dankel
- Department of Health and Exercise Science, Exercise Physiology Laboratory, Rowan University, Glassboro, NJ, USA
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Broadbent P, Schoth DE, Liossi C. Association between attentional bias to experimentally induced pain and to pain-related words in healthy individuals: the moderating role of interpretation bias. Pain 2022; 163:319-333. [PMID: 34086628 DOI: 10.1097/j.pain.0000000000002318] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 04/13/2021] [Indexed: 11/26/2022]
Abstract
ABSTRACT Attentional bias to pain-related information may contribute to chronic pain maintenance. It is theoretically predicted that attentional bias to pain-related language derives from attentional bias to painful sensations; however, the complex interconnection between these types of attentional bias has not yet been tested. This study aimed to investigate the association between attentional bias to pain words and attentional bias to the location of pain, as well as the moderating role of pain-related interpretation bias in this association. Fifty-four healthy individuals performed a visual probe task with pain-related and neutral words, during which eye movements were tracked. In a subset of trials, participants were presented with a cold pain stimulus on one hand. Pain-related interpretation and memory biases were also assessed. Attentional bias to pain words and attentional bias to the pain location were not significantly correlated, although the association was significantly moderated by interpretation bias. A combination of pain-related interpretation bias and attentional bias to painful sensations was associated with avoidance of pain words. In addition, first fixation durations on pain words were longer when the pain word and cold pain stimulus were presented on the same side of the body, as compared to on opposite sides. This indicates that congruency between the locations of pain and pain-related information may strengthen attentional bias. Overall, these findings indicate that cognitive biases to pain-related information interact with cognitive biases to somatosensory information. The implications of these findings for attentional bias modification interventions are discussed.
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Affiliation(s)
| | | | - Christina Liossi
- University of Southampton, Southampton, United Kingdom
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
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10
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Yao J, Li X, Zhang W, Lin X, Lyu X, Lou W, Peng W. Analgesia induced by anodal tDCS and high-frequency tRNS over the motor cortex: Immediate and sustained effects on pain perception. Brain Stimul 2021; 14:1174-1183. [PMID: 34371209 DOI: 10.1016/j.brs.2021.07.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 07/21/2021] [Accepted: 07/25/2021] [Indexed: 10/20/2022] Open
Abstract
BACKGROUND Many studies have shown effects of anodal transcranial direct current stimulation (a-tDCS) and high-frequency transcranial random noise stimulation (tRNS) on elevating cortical excitability. Moreover, tRNS with a direct current (DC)-offset is more likely to lead to increases in cortical excitability than solely tRNS. While a-tDCS over primary motor cortex (M1) has been shown to attenuate pain perception, tRNS + DC-offset may prove as an effective means for pain relief. OBJECTIVE This study aimed to examine effects of a-tDCS and high-frequency tRNS + DC-offset over M1 on pain expectation and perception, and assess whether these effects could be influenced by the certainty of pain expectation. METHODS Using a double-blinded and sham-controlled design, 150 healthy participants were recruited to receive a single-session a-tDCS, high-frequency tRNS + DC-offset, or sham stimulation over M1. The expectation and perception of electrical stimulation in certain and uncertain contexts were assessed at baseline, immediately after, and 30 min after stimulation. RESULTS Compared with sham stimulation, a-tDCS induced immediate analgesic effects that were greater when the stimulation outcome was expected with uncertainty; tRNS induced immediate and sustained analgesic effects that were mediated by decreasing pain expectation. Nevertheless, we found no strong evidence for tRNS being more effective for attenuating pain than a-tDCS. CONCLUSIONS The analgesic effects of a-tDCS and tRNS showed different temporal courses, which could be related to the more sustained effectiveness of high-frequency tRNS + DC-offset in elevating cortical excitability. Moreover, expectations of pain intensity should be taken into consideration to maximize the benefits of neuromodulation.
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Affiliation(s)
- Junjie Yao
- School of Psychology, Shenzhen University, Shenzhen, Guangdong, China
| | - Xiaoyun Li
- School of Psychology, Shenzhen University, Shenzhen, Guangdong, China
| | - Wenyun Zhang
- School of Psychology, Shenzhen University, Shenzhen, Guangdong, China
| | - Xinxin Lin
- School of Psychology, Shenzhen University, Shenzhen, Guangdong, China
| | - Xiaohan Lyu
- School of Psychology, Shenzhen University, Shenzhen, Guangdong, China
| | - Wutao Lou
- Department of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Weiwei Peng
- School of Psychology, Shenzhen University, Shenzhen, Guangdong, China.
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11
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Neige C, Lebon F, Mercier C, Gaveau J, Papaxanthis C, Ruffino C. Pain, No Gain: Acute Pain Interrupts Motor Imagery Processes and Affects Mental Training-Induced Plasticity. Cereb Cortex 2021; 32:640-651. [PMID: 34313709 DOI: 10.1093/cercor/bhab246] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 06/27/2021] [Accepted: 06/28/2021] [Indexed: 12/21/2022] Open
Abstract
Pain influences both motor behavior and neuroplastic adaptations induced by physical training. Motor imagery (MI) is a promising method to recover motor functions, for instance in clinical populations with limited endurance or concomitant pain. However, the influence of pain on the MI processes is not well established. This study investigated whether acute experimental pain could modulate corticospinal excitability assessed at rest and during MI (Exp. 1) and limit the use-dependent plasticity induced by MI practice (Exp. 2). Participants imagined thumb movements without pain or with painful electrical stimulations applied either on digit V or over the knee. We used transcranial magnetic stimulation to measure corticospinal excitability at rest and during MI (Exp. 1) and to evoke involuntary thumb movements before and after MI practice (Exp. 2). Regardless of its location, pain prevented the increase of corticospinal excitability that is classically observed during MI. In addition, pain blocked use-dependent plasticity following MI practice, as testified by a lack of significant posttraining deviations. These findings suggest that pain interferes with MI processes, preventing the corticospinal excitability facilitation needed to induce use-dependent plasticity. Pain should be carefully considered for rehabilitation programs using MI to restore motor function.
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Affiliation(s)
- Cécilia Neige
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, F-21078 Dijon, France
| | - Florent Lebon
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, F-21078 Dijon, France
| | - Catherine Mercier
- Center for Interdisciplinary Research in Rehabilitation and Social Integration, Department of Rehabilitation, Laval University, Québec, QC G1M 2S8, Canada
| | - Jérémie Gaveau
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, F-21078 Dijon, France
| | - Charalambos Papaxanthis
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, F-21078 Dijon, France
| | - Célia Ruffino
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, F-21078 Dijon, France
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12
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Lee VY, Bohn-Goldbaum E, Fong J, Barr IG, Booy R, Edwards KM. Analgesic and adjuvant properties of exercise with vaccinations in healthy young population. Hum Vaccin Immunother 2021; 17:2058-2064. [PMID: 33499711 DOI: 10.1080/21645515.2020.1859322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Introduction: Exercise holds the potential to be beneficial if used during vaccination processes by 1)exercise-induced analgesia to reduce pain associated with vaccination, 2)immune-enhancing effects, improving antibody responses to the vaccine, and 3)reducing local and systemic adverse reactions to the vaccine. This study examines whether analgesic responses could be enhanced locally in the exercising limb to further benefit the use of exercise during influenza vaccination processes to minimize vaccine-related pain and improve antibody response to inactivated influenza vaccines.Methods: 57 participants (22.6 ± 3.2 years, 33 females) randomized into a control (n = 19) or one of two exercise groups: pre-vaccine arm (n = 19) or pre-vaccine leg (n = 19). Intervention groups performed exercise (15 minutes), prior to administration of the vaccine. Vaccine-related pain and pressure pain threshold (PPT) were measured at baseline and post-vaccination for all groups. Blood samples were taken on the day of vaccination and one month later to measure serum antibody titers to influenza.Results: No significant difference in vaccine-related pain or change in PPT was found with exercise, however, there was a trend in higher reports of vaccine-related pain in females compared to males(p = .06). Significantly higher fold increase (p = .02) of the B/Brisbane/60/2008 strain was found in the exercise group compared to the control group.Conclusion: The current study failed to observe an analgesic effect of exercise to improve vaccine-related pain in young adults. However, immune-enhancing effects in one of four strains suggest potential adjuvant effects of exercise. Importantly, the sex difference in pain sensitivity suggests the need for separate analysis, especially when examining pain perception.Australian New Zealand Clinical Trial Registry (ACTRN:12617000374369).
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Affiliation(s)
- Vivian Y Lee
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK.,The University of Sydney, Faculty of Medicine and Health, Sydney School of Health Sciences & Charles Perkins Centre, Sydney, Australia
| | - Erika Bohn-Goldbaum
- The University of Sydney, Faculty of Medicine and Health, Sydney School of Health Sciences & Charles Perkins Centre, Sydney, Australia
| | - Jacqueline Fong
- Susan Wakil School of Nursing and Midwifery, The University of Sydney, Sydney, Australia
| | - Ian G Barr
- WHO Collaborating Centre for Reference and Research on Influenza, VIDRL, Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Robert Booy
- National Centre for Immunisation Research and Surveillance of Vaccine Preventable Diseases, The University of Sydney, Sydney, Australia.,Discipline of Child & Adolescent Health, Faculty of Health and Medicine, Children's Hospital Westmead, The University of Sydney, Australia
| | - Kate M Edwards
- The University of Sydney, Faculty of Medicine and Health, Sydney School of Health Sciences & Charles Perkins Centre, Sydney, Australia
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13
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Mouraux A, Bannister K, Becker S, Finn DP, Pickering G, Pogatzki-Zahn E, Graven-Nielsen T. Challenges and opportunities in translational pain research - An opinion paper of the working group on translational pain research of the European pain federation (EFIC). Eur J Pain 2021; 25:731-756. [PMID: 33625769 PMCID: PMC9290702 DOI: 10.1002/ejp.1730] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
For decades, basic research on the underlying mechanisms of nociception has held promise to translate into efficacious treatments for patients with pain. Despite great improvement in the understanding of pain physiology and pathophysiology, translation to novel, effective treatments for acute and chronic pain has however been limited, and they remain an unmet medical need. In this opinion paper bringing together pain researchers from very different disciplines, the opportunities and challenges of translational pain research are discussed. The many factors that may prevent the successful translation of bench observations into useful and effective clinical applications are reviewed, including interspecies differences, limited validity of currently available preclinical disease models of pain, and limitations of currently used methods to assess nociception and pain in non-human and human models of pain. Many paths are explored to address these issues, including the backward translation of observations made in patients and human volunteers into new disease models that are more clinically relevant, improved generalization by taking into account age and sex differences, and the integration of psychobiology into translational pain research. Finally, it is argued that preclinical and clinical stages of developing new treatments for pain can be improved by better preclinical models of pathological pain conditions alongside revised methods to assess treatment-induced effects on nociception in human and non-human animals. Significance: For decades, basic research of the underlying mechanisms of nociception has held promise to translate into efficacious treatments for patients with pain. Despite great improvement in the understanding of pain physiology and pathophysiology, translation to novel, effective treatments for acute and chronic pain has however been limited, and they remain an unmet medical need.
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Affiliation(s)
- André Mouraux
- Institute of Neuroscience (IONS), UCLouvain, Brussels, Belgium
| | - Kirsty Bannister
- Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Susanne Becker
- Department of Cognitive and Clinical Neuroscience, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,Integrative Spinal Research, Department of Chiropractic Medicine, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - David P Finn
- Pharmacology and Therapeutics, Centre for Pain Research, School of Medicine, National University of Ireland Galway, Galway, Ireland
| | - Gisèle Pickering
- Department of Clinical Pharmacology, Inserm CIC 1405, University Hospital, CHU Clermont-Ferrand, France.,Fundamental and Clinical Pharmacology of Pain, University Clermont Auvergne, Clermont-Ferrand, France
| | - Esther Pogatzki-Zahn
- Department of Anesthesiology, Critical Care Medicine and Pain Therapy, University Hospital Muenster, Muenster, Germany
| | - Thomas Graven-Nielsen
- Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark
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14
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Schindler EAD, Schnakenberg Martin AM, Sewell RA, Ranganathan M, DeForest A, Pittman BP, Perrino A, D'Souza DC. In an exploratory randomized, double-blind, placebo-controlled, cross-over study, psychoactive doses of intravenous delta-9-tetrahydrocannabinol fail to produce antinociceptive effects in healthy human volunteers. Psychopharmacology (Berl) 2020; 237:3097-3107. [PMID: 32632491 DOI: 10.1007/s00213-020-05595-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 06/17/2020] [Indexed: 01/09/2023]
Abstract
RATIONALE Animal studies and anecdotal human reports suggest that cannabinoids have antinociceptive effects. Controlled human studies have produced mixed results. OBJECTIVES We sought to reduce existing variability by investigating the effects of intravenous delta-9-tetrahydrocannabinol (THC) in several pain paradigms within the same human subjects, addressing some of the limitations to the published literature. METHODS In this exploratory randomized, double-blind, placebo-controlled, cross-over study, healthy human subjects received 0.01 mg/kg or 0.03 mg/kg intravenous THC or placebo (ethanol vehicle) infused over 10 min on three test days, each separated by at least 72 h. Capsaicin (250 μg) was injected intradermally to induce chemical pain and hyperalgesia. Four other forms of acute pain were induced: mechanical (von Frey filament), hot and cold (thermode), and electrical (pulse generator). Pain ratings were obtained before drug administration, at peak drug effects, and 2 h after drug administration and included both objective and subjective measures. THC drug effects and vital signs were also collected during experimental sessions. Nonparametric analysis with repeated measures was performed. RESULTS THC induced euphoria, perceptual and cognitive alterations, and tachycardia in a dose-related manner, but failed to have significant effects in experimentally induced acute chemical, mechanical, thermal, or electrical pain and capsaicin-induced hyperalgesia. CONCLUSIONS In this exploratory controlled study, intravenous THC lacked significant antinociceptive properties in experimental models of acute pain and capsaicin-induced hyperalgesia in healthy human subjects. Continued study of THC and other cannabinoids through high-quality, controlled studies in both healthy volunteers and patients with pain conditions is warranted to inform the growing demand for the clinical application of cannabinoids in pain management.
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Affiliation(s)
- Emmanuelle A D Schindler
- Neurology Service, MS 127, Veterans Affairs (VA) Connecticut Healthcare System, 950 Campbell Avenue, West Haven, CT, 06516, USA. .,Department of Neurology, Yale School of Medicine, New Haven, CT, USA.
| | - Ashley M Schnakenberg Martin
- Psychology Service, VA Connecticut Healthcare System, West Haven, CT, USA.,Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA
| | - R Andrew Sewell
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA.,Psychiatry Service, VA Connecticut Healthcare System, West Haven, CT, USA
| | - Mohini Ranganathan
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA.,Psychiatry Service, VA Connecticut Healthcare System, West Haven, CT, USA
| | - Anna DeForest
- Neurology Service, MS 127, Veterans Affairs (VA) Connecticut Healthcare System, 950 Campbell Avenue, West Haven, CT, 06516, USA.,Department of Neurology, Yale School of Medicine, New Haven, CT, USA
| | - Brian P Pittman
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA
| | - Albert Perrino
- Anesthesia Service, VA Connecticut Healthcare System, West Haven, CT, USA.,Department of Anesthesia, Yale School of Medicine, New Haven, CT, USA
| | - Deepak C D'Souza
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA.,Psychiatry Service, VA Connecticut Healthcare System, West Haven, CT, USA
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15
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Posada-Quintero HF, Kong Y, Nguyen K, Tran C, Beardslee L, Chen L, Guo T, Cong X, Feng B, Chon KH. Using electrodermal activity to validate multilevel pain stimulation in healthy volunteers evoked by thermal grills. Am J Physiol Regul Integr Comp Physiol 2020; 319:R366-R375. [PMID: 32726157 DOI: 10.1152/ajpregu.00102.2020] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have tested the feasibility of thermal grills, a harmless method to induce pain. The thermal grills consist of interlaced tubes that are set at cool or warm temperatures, creating a painful "illusion" (no tissue injury is caused) in the brain when the cool and warm stimuli are presented collectively. Advancement in objective pain assessment research is limited because the gold standard, the self-reporting pain scale, is highly subjective and only works for alert and cooperative patients. However, the main difficulty for pain studies is the potential harm caused to participants. We have recruited 23 subjects in whom we induced electric pulses and thermal grill (TG) stimulation. The TG effectively induced three different levels of pain, as evidenced by the visual analog scale (VAS) provided by the subjects after each stimulus. Furthermore, objective physiological measurements based on electrodermal activity showed a significant increase in levels as stimulation level increased. We found that VAS was highly correlated with the TG stimulation level. The TG stimulation safely elicited pain levels up to 9 out of 10. The TG stimulation allows for extending studies of pain to ranges of pain in which other stimuli are harmful.
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Affiliation(s)
| | | | | | - Cara Tran
- University of Connecticut, Storrs, Connecticut
| | - Luke Beardslee
- Emory University School of Medicine Department of Surgery, Atlanta, Georgia
| | - Longtu Chen
- University of Connecticut, Storrs, Connecticut
| | | | | | - Bin Feng
- University of Connecticut, Storrs, Connecticut
| | - Ki H Chon
- University of Connecticut, Storrs, Connecticut
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16
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Al Sayegh S, Vasilatou I, Kumar A, Al Barwari C, Fredriksson L, Grigoriadis A, Christidis N. Experimental pain and fatigue induced by excessive chewing. BMC Oral Health 2020; 20:179. [PMID: 32600327 PMCID: PMC7322929 DOI: 10.1186/s12903-020-01161-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 06/08/2020] [Indexed: 12/18/2022] Open
Abstract
Background The study was aiming to optimize excessive gum chewing as an experimental model to induce jaw muscle pain and fatigue similar to those in painful TMDs with durations that would allow immediate investigations of jaw-motor function. Further, if any sex differences would be detected in the expression of pain. Methods This randomized, double blinded study included 31 healthy participants of both sexes. A standardized chewing protocol of either 40- or 60-min of chewing was used with a wash-out period of 1 week. Subjective fatigue, pain characteristics and functional measures were assessed. For statistical analyses, Wilcoxon Signed Rank test, Mann–Whitney Rank Sum test and Friedman’s ANOVA with Tukey post-hoc test were used. Results High subjective fatigue scores that lasted up to 20 min after the end of the trial were significantly induced both in the 40- and 60-min chewing trials (P < 0.001*). Significant but mild pain was induced only in the 60-min trial (P = 0.004*) and only in men (P = 0.04*). Also, the induced pain area was significantly bigger in the 60-min trial (P = 0.009*). However, this increase in pain and pain area did not last to the first 10-min follow-up. There were no significant differences neither between the 40- and 60-min chewing trials, except regarding the pain area (P = 0.008*), nor between the sexes. Conclusion Taken together, excessive chewing in its current form does not seem to be a proper pain experimental model. The model needs further adjustments in order to mimic TMD-pain especially in women and to prolong the pain duration.
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Affiliation(s)
- Samaa Al Sayegh
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, Box 4046, SE-141 04, Huddinge, Sweden. .,Scandinavian Center for Orofacial Neurosciences (SCON), Huddinge, Sweden.
| | - Ioanna Vasilatou
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, Box 4046, SE-141 04, Huddinge, Sweden
| | - Abhishek Kumar
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, Box 4046, SE-141 04, Huddinge, Sweden.,Scandinavian Center for Orofacial Neurosciences (SCON), Huddinge, Sweden
| | - Ceva Al Barwari
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, Box 4046, SE-141 04, Huddinge, Sweden
| | - Lars Fredriksson
- Department of Clinical Oral Physiology at the Eastman Institute, Folktandvården Stockholms län AB, SE-113 24, Stockholm, Sweden
| | - Anastasios Grigoriadis
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, Box 4046, SE-141 04, Huddinge, Sweden.,Scandinavian Center for Orofacial Neurosciences (SCON), Huddinge, Sweden
| | - Nikolaos Christidis
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, Box 4046, SE-141 04, Huddinge, Sweden.,Scandinavian Center for Orofacial Neurosciences (SCON), Huddinge, Sweden
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17
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Muscle pain induced by hypertonic saline in the knee extensors decreases single-limb isometric time to task failure. Eur J Appl Physiol 2020; 120:2047-2058. [PMID: 32613451 PMCID: PMC7419372 DOI: 10.1007/s00421-020-04425-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 06/19/2020] [Indexed: 12/02/2022]
Abstract
Purpose Increased nociceptive activity and the experience of exercise-induced pain (EIP) may contribute to fatigue during endurance exercise. To investigate this, a pain model that produces pain similar to EIP and decouples its relationship to exercise intensity is required. This study (1) compared the quality of pain caused by a hypertonic saline injection into the vastus lateralis in resting and exercise conditions, and (2) investigated whether this pain contributes to changes in time to task failure. Methods On separate days, 18 participants completed a time to task failure at 20% maximal voluntary torque (MVT), a resting hypertonic saline intramuscular injection, and in a further three visits a time to task failure at 10% MVT following injection of isotonic saline, hypertonic saline or a control (no injection). Results In a subset of eligible participants (n = 12), the hypertonic saline combined with 10% MVT produced a qualitative experience of pain (assessed by the McGill Pain Questionnaire) that felt similar to EIP. 10% MVT with hypertonic saline significantly elevated pain intensity in the first 20% of the time to task failure and caused a significantly (P < 0.05) shorter time to task failure (448 ± 240 s) compared with the isotonic saline (605 ± 285 s) and control (514 ± 197 s) conditions. Conclusion These findings demonstrate that hypertonic saline increases the intensity of pain during exercise, which results in a faster occurrence of exercise-induced fatigue. These results provide important evidence supporting pain as a limiting factor in endurance performance.
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18
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Cayrol T, Lebleu J, Mouraux A, Roussel N, Pitance L, van den Broeke EN. Within- and between-session reliability of secondary hyperalgesia induced by electrical high-frequency stimulation. Eur J Pain 2020; 24:1585-1597. [PMID: 32501583 DOI: 10.1002/ejp.1613] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 04/27/2020] [Accepted: 05/31/2020] [Indexed: 11/09/2022]
Abstract
BACKGROUND An increasing number of studies are focusing on secondary hyperalgesia to better understand central sensitization, as this phenomenon may play an important role in persistent pain. Recent studies have shown that, compared to the classical high-frequency stimulation protocol (HFS) at 100 Hz, a protocol using 42 Hz stimulation induces a more intense and a larger area of secondary hyperalgesia (SH). OBJECTIVES The aim of this study was to investigate the within- and between-session reliability of SH induced by this optimized HFS protocol. METHODS Thirty-two healthy subjects received HFS to their volar forearm in two sessions, separated by at least 2 weeks. SH was assessed by measuring the area size of increased sensitivity to pinprick stimuli after applying HFS, the sensitivity to pinprick stimuli after applying HFS and the change in pinprick sensitivity after versus before HFS. Assessments were made before HFS, and 30, 35 and 40 min after HFS. Relative and absolute reliability were analysed using intraclass correlation coefficients (ICCs), coefficients of variation (CVs), standard error of means (SEMs) and the minimum detectable changes (MDCs). RESULTS The area of SH showed good to excellent within-session and between-session relative reliability (ICCs > 0.80), except for the change in pinprick sensitivity, which showed close to poor between-session relative reliability (ICC = 0.53). Furthermore, measures of absolute reliability generally demonstrated large between-subject variability and significant fluctuations across repeated measurements. CONCLUSIONS HFS-induced hyperalgesia is suitable to discriminate or compare individuals but it may not be sensitive to changes due to an intervention. SIGNIFICANCE It is crucial to evaluate central sensitization adequately in humans. This study formally establishes the reliability of secondary hyperalgesia induced by electrical high-frequency stimulation. The results of this study will improve future studies investigating secondary hyperalgesia in humans.
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Affiliation(s)
- Timothée Cayrol
- Institute of Experimental and Clinical Research, Health Sciences Division, Université Catholique de Louvain, Neuro-Musculo-Skeletal-Lab (NMSK), Brussels, Belgium
| | - Julien Lebleu
- Institute of Experimental and Clinical Research, Health Sciences Division, Université Catholique de Louvain, Neuro-Musculo-Skeletal-Lab (NMSK), Brussels, Belgium
| | - André Mouraux
- Institute of Neuroscience, System and Cognition Division, Université Catholique de Louvain, Brussels, Belgium
| | - Nathalie Roussel
- Department of Rehabilitation Sciences and Physiotherapy (MOVANT), Faculty of Medicine and Health Sciences, University of Antwerp, Wilrijk, Belgium
| | - Laurent Pitance
- Institute of Experimental and Clinical Research, Health Sciences Division, Université Catholique de Louvain, Neuro-Musculo-Skeletal-Lab (NMSK), Brussels, Belgium
| | - Emanuel N van den Broeke
- Institute of Neuroscience, System and Cognition Division, Université Catholique de Louvain, Brussels, Belgium
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19
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Mastilović G, Konstantinović U, Đorđević O. Human experimental pain models. MEDICINSKI PODMLADAK 2020. [DOI: 10.5937/mp71-27417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
Pain is an unpleasant sensory experience, associated with existing or potential tissue damage. It has also strong cognitive and emotional components. Stimuli that causes pain goes through process of nociception, which includes transduction, transmission, modulation and perception of said stimuli. Depending on the type of stimuli, we can classify human experimental pain models into mechanical, electrical, thermal and chemical. Information about pain mechanisms can be obtained from the following: 1) in vitro studies, 2) animal experiments, 3) human experimental pain studies and 4) clinical studies. Chosing the appropriate method for pain evaluation is a key step in the design of pain studies. Combining it with different electro-physiological and imaging methods, it can provide better objectivity and quantification of pain mechanisms. Focus in experimental pain studies is slowly shifting from static parameters of pain, such as pain threshold and maximum tolerance, to dynamic parameters, which can give us valuable insight in function of endogenous analgesic systems. This can be done using conditioned pain modulation. Using experimental pain on healthy voulenteers is key step in switching from animal models to clinical studies, foremost for validization of data from animals, making them important in translational research. Results from experimental pain studies can help us in understanding nociceptive mechanisms of acute and chronic pain, alongside development of new therapeutic modalities.
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20
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Gozani SN. Remote Analgesic Effects Of Conventional Transcutaneous Electrical Nerve Stimulation: A Scientific And Clinical Review With A Focus On Chronic Pain. J Pain Res 2019; 12:3185-3201. [PMID: 31819603 PMCID: PMC6885653 DOI: 10.2147/jpr.s226600] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 11/02/2019] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Transcutaneous electrical nerve stimulation (TENS) is a safe, noninvasive treatment for chronic pain that can be self-administered. Conventional TENS involves stimulation of peripheral sensory nerves at a strong, non-painful level. Following the original gate-control theory of pain, stimulation is typically near the target pain. As another option, remote stimulation may also be effective and offers potential advantages. OBJECTIVE This narrative review examines mechanisms underlying the remote analgesic effects of conventional TENS and appraises the clinical evidence. METHODS A literature search for English-language articles was performed on PubMed. Keywords included terms related to the location of TENS . Citations from primary references and textbooks were examined for additional articles. RESULTS Over 30 studies reported remote analgesic effects of conventional TENS. The evidence included studies using animal models of pain, experimental pain in humans, and clinical studies in subjects with chronic pain. Three types of remote analgesia were identified: at the contralateral homologous site, at sites distant from stimulation but innervated by overlapping spinal segments, and at unrelated extrasegmental sites. CONCLUSION There is scientific and clinical evidence that conventional TENS has remote analgesic effects. This may occur through modulation of pain processing at the level of the dorsal horn, in brainstem centers mediating descending inhibition, and within the pain matrix. A broadening of perspectives on how conventional TENS produces analgesia may encourage researchers, clinicians, and medical-device manufacturers to develop novel ways of using this safe, cost-effective neuromodulation technique for chronic pain.
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21
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Janner H, Klausenitz C, Gürtler N, Hahnenkamp K, Usichenko TI. Effects of Electrical Transcutaneous Vagus Nerve Stimulation on the Perceived Intensity of Repetitive Painful Heat Stimuli: A Blinded Placebo- and Sham-Controlled Randomized Crossover Investigation. Anesth Analg 2019; 126:2085-2092. [PMID: 29337730 DOI: 10.1213/ane.0000000000002820] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND Transcutaneous vagus nerve stimulation (TVNS) is a promising treatment for acute and chronic pain. However, experimental studies yielded controversial results. We examined if TVNS reduces the perceived intensity of repetitive painful heat stimulation and temporal summation of pain (TSP) in healthy volunteers in comparison with placebo and sham stimulation, as well as no intervention. METHODS In 4 sessions, 90 heat pulse stimuli at individual pain tolerance temperature were applied to the ventral forearm of 49 healthy volunteers (25 women) using a Contact Heat Evoked Potential Stimulator thermode (Medoc, Ramat Yishai, Israel). Pain intensity was assessed with verbal ratings on a numeric pain scale (0-100) at every tenth heat pulse. After the first session in which pain intensities without intervention were evaluated, participants completed 3 sessions in a single-blinded randomized crossover manner: (1) sham stimulation applied at the earlobes, (2) placebo stimulation (inactive device), or (3) TVNS applied at the cymbas conchae. Primary data were analyzed using analysis of variance for repeated measures and t test for paired samples. RESULTS Pain intensity decreased during all interventions as compared to no intervention (ηp = 0.22, P < .001; mean difference TVNS versus no intervention 9.5; 95% confidence interval [CI], 3.6-15.4; P < .001). Hypoalgesic effect of TVNS was better than that of placebo and sham in men before the onset of TSP (mean differences for TVNS versus placebo 6.2; 95% CI, 0.2-12.1; TVNS versus sham 6.2; 95% CI, 0.2-12.1; P < .05). In women, TSP response under TVNS was decreased if compared to no intervention (median difference, 7.5; 95% CI, 3.5-15.0; P = .003). CONCLUSIONS TVNS, placebo, and sham stimulation exerted comparable effects under experimental heat pain stimulation. Only in male participants, TVNS was superior to sham and placebo conditions in the reduction of heat pain before the onset of TSP.
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Affiliation(s)
| | - Catharina Klausenitz
- Institute of Diagnostic Radiology and Neuroradiology, University Medicine of Greifswald, Greifswald, Germany
| | | | | | - Taras I Usichenko
- From the Department of Anesthesiology.,Department of Anesthesia, McMaster University, Hamilton, Ontario, Canada
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22
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Qu N, Lindstrøm R, Graven-Nielsen T, Hirata RP. Experimental cervical interspinous ligament pain altered cervical joint motion during dynamic extension movement. Clin Biomech (Bristol, Avon) 2019; 65:65-72. [PMID: 30991232 DOI: 10.1016/j.clinbiomech.2019.04.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 03/26/2019] [Accepted: 04/02/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND Although the cervical interspinous ligament is a potential source of neck pain, the effects on cervical joint motion and pressure pain sensitivity has never been investigated. The understanding of the relationship will broaden our understanding of cervical biomechanics and improve diagnosis and treatment of neck pain. METHODS Fluoroscopy videos of cervical flexion and extension movements and pressure pain thresholds over bilateral C2/C3 and C5/C6 facet joints were collected in fifteen healthy subjects before and after injections of hypertonic and isotonic saline in C4/C5 ISL. The videos were divided into 10 even epochs and the motion of individual joints during each epoch was extracted. Joint motion parameters including anti-directional motion, pro-directional motion, total joint motion and joint motion variability were extracted across epochs. Joint motion parameters and PPTs were compared before and after injection of hypertonic and isotonic saline separately. FINDINGS Compared with baselines: hypertonic saline injection 1) decreased anti-directional motion and joint motion variability at C4/C5 (P < 0.05) and increased at C2/C3 (P < 0.05) during extension; 2) increased total joint motion of C0/C1 during first half range (P < 0.05) and decreased during second half range of extension, and total joint motion of C2/C3 increased during second half range of extension (P < 0.05) and; 3) increased pressure pain thresholds over left C2/C3 facet joint (P < 0.01). INTERPRETATION The cervical interspinous ligament pain redistributed anti-directional motion between C4/C5 and C2/C3 during dynamic extension and decreased pressure pain sensitivity over the left C2/C3 facet joint.
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Affiliation(s)
- Ning Qu
- SMI, Department of Health and Science Technology, Faculty of Medicine, Aalborg University, Denmark
| | - Rene Lindstrøm
- SMI, Department of Health and Science Technology, Faculty of Medicine, Aalborg University, Denmark
| | - Thomas Graven-Nielsen
- Center for Neuroplasticity and Pain (CNAP), SMI, Department of Health and Science Technology, Faculty of Medicine, Aalborg University, Denmark
| | - Rogerio Pessoto Hirata
- SMI, Department of Health and Science Technology, Faculty of Medicine, Aalborg University, Denmark.
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Measurements of Temporal Summation of Heat Pain: a Pilot Investigation in Healthy Humans. NEUROPHYSIOLOGY+ 2019. [DOI: 10.1007/s11062-019-09773-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Kuhlmann L, Olesen SS, Olesen AE, Arendt-Nielsen L, Drewes AM. Mechanism-based pain management in chronic pancreatitis - is it time for a paradigm shift? Expert Rev Clin Pharmacol 2019; 12:249-258. [PMID: 30664364 DOI: 10.1080/17512433.2019.1571409] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
INTRODUCTION Pain is the most common symptom in chronic pancreatitis and treatment remains a challenge. Management of visceral pain, in general, is only sparsely documented, and treatment in the clinic is typically based on empirical knowledge from somatic pain conditions. This may be problematic, as many aspects of the neurobiology differ significantly from somatic pain, and organs such as the gut and liver play a major role in tolerability to analgesics. On the other hand, clinical awareness and new methods for quantitative assessment of pain mechanisms, will likely increase our understanding of the visceral pain system and guide more individualized pain management. Areas covered: This review includes an overview of known pain mechanisms in chronic pancreatitis and how to characterize them using quantitative sensory testing. The aim is to provide a mechanism-oriented approach to analgesic treatment, including treatment of psychological factors affecting pain perception and consideration of side effects in the management plan. Expert opinion: A mechanism-based examination and profiling of pain in chronic pancreatitis will enable investigators to provide a well-substantiated approach to effective management. This mechanism-based, individualized regime will pave the road to better pain relief and spare the patient from unnecessary trial-and-error approaches and unwanted side effects.
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Affiliation(s)
- Louise Kuhlmann
- a Centre for Pancreatic Diseases and Mech-Sense, Department of Gastroenterology and Hepatology , Aalborg University Hospital , Aalborg , Denmark.,b Department of Internal Medicine , North Denmark Regional Hospital , Hjørring , Denmark.,c Department of Clinical Medicine , Aalborg University , Aalborg , Denmark
| | - Søren S Olesen
- a Centre for Pancreatic Diseases and Mech-Sense, Department of Gastroenterology and Hepatology , Aalborg University Hospital , Aalborg , Denmark.,c Department of Clinical Medicine , Aalborg University , Aalborg , Denmark
| | - Anne E Olesen
- a Centre for Pancreatic Diseases and Mech-Sense, Department of Gastroenterology and Hepatology , Aalborg University Hospital , Aalborg , Denmark.,c Department of Clinical Medicine , Aalborg University , Aalborg , Denmark
| | - Lars Arendt-Nielsen
- d Center for Sensory-Motor Interaction, School of Medicine , Aalborg University , Aalborg , Denmark
| | - Asbjørn M Drewes
- a Centre for Pancreatic Diseases and Mech-Sense, Department of Gastroenterology and Hepatology , Aalborg University Hospital , Aalborg , Denmark.,c Department of Clinical Medicine , Aalborg University , Aalborg , Denmark
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Siebenga PS, van Amerongen G, Klaassen ES, de Kam ML, Rissmann R, Groeneveld GJ. The ultraviolet B inflammation model: Postinflammatory hyperpigmentation and validation of a reduced UVB exposure paradigm for inducing hyperalgesia in healthy subjects. Eur J Pain 2019; 23:874-883. [PMID: 30597682 PMCID: PMC6590423 DOI: 10.1002/ejp.1353] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 12/17/2018] [Accepted: 12/23/2018] [Indexed: 12/18/2022]
Abstract
Background Pain models are commonly used in drug development to demonstrate analgesic activity in healthy subjects and should therefore not cause long‐term adverse effects. The ultraviolet B (UVB) model is a model for inflammatory pain in which three times the minimal erythema dose (3MED) is typically applied to induce sensitization. Based on reports of long‐lasting postinflammatory hyperpigmentation (PIH) associated with 3MED, it was decided to investigate the prevalence of PIH among subjects who were previously exposed to 3MED at our research centre. In addition, re‐evaluation of the UVB inflammation model using a reduced exposure paradigm (2MED) was performed in healthy subjects. Methods In the first study, all 142 subjects previously exposed to 3MED UVB were invited for a clinical evaluation of PIH. In the second study, 18 healthy subjects were exposed to 2MED UVB, and heat pain detection threshold (PDT) and PIH were evaluated. Results In total, 78 of the 142 subjects responded. The prevalence of PIH among responders was 53.8%. In the second study, we found a significant and stable difference in PDT between UVB‐exposed and control skin 3 hr after irradiation; 13 hr post‐irradiation, the least squares mean estimate of the difference in PDT ranged from −2.6°C to −4.5°C (p < 0.0001). Finally, the prevalence of PIH was lower in the 2MED group compared to the 3MED group. Conclusions The 3MED model is associated with a relatively high prevalence of long‐lasting PIH. In contrast, 2MED exposure produces stable hyperalgesia and has a lower risk of PIH and is therefore recommended for modelling inflammatory pain. Significance Postinflammatory hyperpigmentation is an unwanted long‐term side effect associated with the UVB inflammation model using the 3× minimal erythema dose (3MED) paradigm. In contrast, using a 2MED paradigm results in hyperalgesia that is stable for 36 hr and has a lower risk of inducing postinflammatory hyperpigmentation.
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Affiliation(s)
| | | | | | | | - Robert Rissmann
- Centre for Human Drug Research, Leiden, The Netherlands.,Leiden University Medical Centre, Leiden, The Netherlands.,Leiden Academic Centre for Drug Research, Leiden, The Netherlands
| | - Geert Jan Groeneveld
- Centre for Human Drug Research, Leiden, The Netherlands.,Leiden University Medical Centre, Leiden, The Netherlands
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Klein C, Caumo W, Gélinas C, Patines V, Pilger T, Lopes A, Backes FN, Villas-Boas DF, Vieira SRR. Validation of Two Pain Assessment Tools Using a Standardized Nociceptive Stimulation in Critically Ill Adults. J Pain Symptom Manage 2018; 56:594-601. [PMID: 30009967 DOI: 10.1016/j.jpainsymman.2018.06.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 06/23/2018] [Accepted: 06/25/2018] [Indexed: 11/19/2022]
Abstract
CONTEXT The Behavioral Pain Scale (BPS) or the Critical-Care Pain Observation Tool (CPOT) are recommended in practice guidelines for pain assessment in critically ill adults unable to self-report. However, their use in another language requires cultural adaptation and validation testing. OBJECTIVES Cross-cultural adaptation of the CPOT and BPS English versions into Brazilian Portuguese, and their validation by comparing behavioral scores during rest, standardized nociceptive stimulation by pressure algometry (SNSPA), and turning were completed. In addition, we explored clinical variables that could predict the CPOT and BPS scores. METHODS A prospective cohort study was conducted with 168 medical-surgical critically ill adults unable to self-report in the intensive care unit. Two nurses were trained to use the CPOT and BPS Brazilian Portuguese versions at the following assessments: 1) baseline at rest, 2) after SNSPA with a pressure of 14 kgf/cm2, 3) during turning, and 4) 15 minutes after turning. RESULTS Inter-rater reliability of nurses' CPOT and BPS scores was supported by high weighted kappa >0.7. Discriminative validation was supported with higher CPOT and BPS scores during SNSPA or turning in comparison to baseline (P < 0.001). The Glasgow Coma Scale score was the only variable that predicted CPOT and BPS scores with explained variance of 44.5% and 55.2%, respectively. CONCLUSION The use of the Brazilian CPOT and BPS versions showed good reliability and validity in critically ill adults unable to self-report. A standardized procedure, the SNSPA, was used for the first time in the validation process of these tools and helped us improve the validation process.
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Affiliation(s)
- Cristini Klein
- Department of Intensive Care Medicine, Clinicas Hospital from Porto Alegre (HCPA), Porto Alegre, Brazil; Post Graduate Program in Medical Sciences, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil; Laboratory of Pain & Neuromodulation, HCPA/UFRGS, Porto Alegre, Brazil.
| | - Wolnei Caumo
- Post Graduate Program in Medical Sciences, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil; Laboratory of Pain & Neuromodulation, HCPA/UFRGS, Porto Alegre, Brazil
| | - Céline Gélinas
- Ingram School of Nursing, McGill University, Montreal, Quebec, Canada
| | - Valéria Patines
- Department of Intensive Care Medicine, Clinicas Hospital from Porto Alegre (HCPA), Porto Alegre, Brazil
| | - Tatiana Pilger
- Department of Intensive Care Medicine, Clinicas Hospital from Porto Alegre (HCPA), Porto Alegre, Brazil
| | - Alexandra Lopes
- Department of Intensive Care Medicine, Clinicas Hospital from Porto Alegre (HCPA), Porto Alegre, Brazil
| | - Fabiane Neiva Backes
- Department of Intensive Care Medicine, Clinicas Hospital from Porto Alegre (HCPA), Porto Alegre, Brazil; Post Graduate Program in Medical Sciences, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | - Débora Feijó Villas-Boas
- Department of Intensive Care Medicine, Clinicas Hospital from Porto Alegre (HCPA), Porto Alegre, Brazil; School of Nursing, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Silvia Regina Rios Vieira
- Department of Intensive Care Medicine, Clinicas Hospital from Porto Alegre (HCPA), Porto Alegre, Brazil; Post Graduate Program in Medical Sciences, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
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27
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Hoff DAL, McMahon B, Gregersen H. Esophageal multimodal stimulation and sensation. Ann N Y Acad Sci 2018; 1434:210-218. [DOI: 10.1111/nyas.13730] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 03/16/2018] [Accepted: 03/21/2018] [Indexed: 12/17/2022]
Affiliation(s)
- Dag Arne Lihaug Hoff
- Division of Gastroenterology and Hepatology, Department of Medicine, Ålesund HospitalMøre and Romsdal Hospital Trust Ålesund Norway
| | - Barry McMahon
- Trinity Academic Gastroenterology Group (TAGG)Trinity College and Tallaght Hospital Dublin Ireland
| | - Hans Gregersen
- Department of Surgerythe Chinese University of Hong Kong Shatin Hong Kong
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28
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Gregersen H, Lo KM. What Is the Future of Impedance Planimetry in Gastroenterology? J Neurogastroenterol Motil 2018; 24:166-181. [PMID: 29605974 PMCID: PMC5885717 DOI: 10.5056/jnm18013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 02/09/2018] [Indexed: 12/13/2022] Open
Abstract
The gastrointestinal (GI) tract is efficient in transporting ingested material to the site of delivery in healthy subjects. A fine balance exists between peristaltic forces, the mixing and delivery of the contents, and sensory signaling. This fine balance is easily disturbed by diseases. It is mandatory to understand the pathophysiology to enhance our understanding of GI disorders. The inaccessibility and complex nervous innervation, geometry and mechanical function of the GI tract make mechanosensory evaluation difficult. Impedance planimetry is a distension technology that assesses luminal geometry, mechanical properties including muscle dynamics, and processing of nociceptive signals from the GI tract. Since standardized models do not exist for GI muscle function in vivo, models, concepts, and terminology must be borrowed from other medical fields such as cardiac mechanophysiology. The review highlights the impedance planimetric technology, muscle dynamics assessment, and 3 applied technologies of impedance planimetry. These technologies are the multimodal probes that assesses sensory function, the functional luminal imaging probe that dynamically measures the geometry of the lumen it distends, and Fecobionics that is a simulated feces providing high-resolution measurements during defecation. The advanced muscle analysis and 3 applied technologies can enhance the quality of future interdisciplinary research for gaining more knowledge about mechanical function, sensory-motor disorders, and symptoms. This is a step in the direction of individualized treatment for GI disorders based on diagnostic subtyping. There seems to be no better alternatives to impedance planimetry, but only the functional luminal imaging probe is currently commercially available. Wider use depends on commercialization of the multimodal probe and Fecobionics.
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Affiliation(s)
- Hans Gregersen
- GIOME, Department of Surgery, The Chinese University of Hong Kong, Shatin, Hong Kong.,California Medical Innovations Institute, San Diego, California, USA
| | - Kar Man Lo
- GIOME Doublecove, Wu Kai Sha, New Territories, Hong Kong
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29
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Characterization of a novel capsaicin/heat ongoing pain model. Eur J Pain 2017; 22:370-384. [DOI: 10.1002/ejp.1126] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2017] [Indexed: 12/27/2022]
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30
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Coe MA, Nuzzo PA, Lofwall MR, Walsh SL. Effects of Short-Term Oxycodone Maintenance on Experimental Pain Responses in Physically Dependent Opioid Abusers. THE JOURNAL OF PAIN 2017; 18:825-834. [PMID: 28274698 PMCID: PMC5484728 DOI: 10.1016/j.jpain.2017.02.433] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 01/26/2017] [Accepted: 02/20/2017] [Indexed: 11/16/2022]
Abstract
A common clinical problem with opioid analgesics is the loss of analgesic efficacy after repeated dosing; when this occurs, it is not clear what principles should guide providing effective analgesia among opioid-dependent individuals. This within-subject inpatient study aimed to determine if physically dependent opioid abusers (n = 11) experience changes in oxycodone-induced analgesia during 2 oxycodone maintenance (30 mg orally 4 times per day) phases: initial stabilization (days 1-3) and after 6 weeks of chronic dosing. Six sessions (3 each phase), measured threshold, tolerance, and pain ratings for a Pressure Pain Test and Cold Pressor Test after a single double-blind dose of oxycodone 30 mg (initial stabilization) and 0, 30, and 60 mg (chronic dosing) given in place of a scheduled maintenance dose. Physiologic and opioid agonist effects were assessed during chronic dosing sessions. There was no analgesic response to oxycodone 30 mg. Oxycodone (60 mg) produced a 25% increase in peak Cold Pressor Test threshold compared with placebo, and significantly increased expired breath CO2, miosis, and ratings of abuse liability measures. These data suggest that more than twice the acute oxycodone maintenance dose is needed to produce robust acute analgesia, although adverse effects (eg, respiratory depression and abuse signals) may occur with lower doses. PERSPECTIVE To understand sensitivity to opioid analgesia in opioid-dependent individuals, this article describes experimental pain, subjective and physiological responses during stabilization and after 6 weeks of oxycodone maintenance. Oxycodone produced euphoric effects and miosis with limited evidence of analgesia.
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Affiliation(s)
- Marion A Coe
- Department of Pharmacology, College of Medicine, University of Kentucky, Lexington, Kentucky; Center on Drug and Alcohol Research, College of Medicine, University of Kentucky, Lexington, Kentucky.
| | - Paul A Nuzzo
- Center on Drug and Alcohol Research, College of Medicine, University of Kentucky, Lexington, Kentucky
| | - Michelle R Lofwall
- Center on Drug and Alcohol Research, College of Medicine, University of Kentucky, Lexington, Kentucky; Department of Behavioral Science, College of Medicine, University of Kentucky, Lexington, Kentucky; Department of Psychiatry, College of Medicine, University of Kentucky, Lexington, Kentucky
| | - Sharon L Walsh
- Department of Pharmacology, College of Medicine, University of Kentucky, Lexington, Kentucky; Center on Drug and Alcohol Research, College of Medicine, University of Kentucky, Lexington, Kentucky; Department of Behavioral Science, College of Medicine, University of Kentucky, Lexington, Kentucky; Department of Psychiatry, College of Medicine, University of Kentucky, Lexington, Kentucky; Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky
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31
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Postinflammatory hyperpigmentation after human cold pain testing. Pain Rep 2017; 1. [PMID: 28664196 PMCID: PMC5486980 DOI: 10.1097/pr9.0000000000000569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
After assessment of thermal sensitivity during development of a novel cold pain assay, one subject developed postinflammatory hyperpigmentation. Resultant epidermal darkening gradually faded without clinical intervention. Changes in cold temperature sensitivity are often associated with chronic pain conditions. Progress in understanding the neurobiological mechanism underlying these changes and resulting development of effective therapies has been slowed by the accessibility and affordability of devices used to measure thermal sensitivity in humans. To address this gap, we developed an inexpensive method to measure cold pain thresholds in healthy adult volunteers using dry ice and a thermode. However, early in preliminary testing, a subject presented with epidermal postinflammatory hyperpigmentation that lasted for >200 days. Although this response was unique among the small number of subjects in development of the assay, it raised questions as to the safety of the assay design.
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Navarro-Guerrero N, Lowe RJ, Wermter S. Improving Robot Motor Learning with Negatively Valenced Reinforcement Signals. Front Neurorobot 2017; 11:10. [PMID: 28420976 PMCID: PMC5376586 DOI: 10.3389/fnbot.2017.00010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 02/17/2017] [Indexed: 11/18/2022] Open
Abstract
Both nociception and punishment signals have been used in robotics. However, the potential for using these negatively valenced types of reinforcement learning signals for robot learning has not been exploited in detail yet. Nociceptive signals are primarily used as triggers of preprogrammed action sequences. Punishment signals are typically disembodied, i.e., with no or little relation to the agent-intrinsic limitations, and they are often used to impose behavioral constraints. Here, we provide an alternative approach for nociceptive signals as drivers of learning rather than simple triggers of preprogrammed behavior. Explicitly, we use nociception to expand the state space while we use punishment as a negative reinforcement learning signal. We compare the performance—in terms of task error, the amount of perceived nociception, and length of learned action sequences—of different neural networks imbued with punishment-based reinforcement signals for inverse kinematic learning. We contrast the performance of a version of the neural network that receives nociceptive inputs to that without such a process. Furthermore, we provide evidence that nociception can improve learning—making the algorithm more robust against network initializations—as well as behavioral performance by reducing the task error, perceived nociception, and length of learned action sequences. Moreover, we provide evidence that punishment, at least as typically used within reinforcement learning applications, may be detrimental in all relevant metrics.
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Affiliation(s)
| | - Robert J Lowe
- Division of Cognition and Communication, Department of Applied IT, University of Gothenburg, Gothenburg, Sweden.,Interaction Lab, School of Informatics, University of Skövde, Skövde, Sweden
| | - Stefan Wermter
- Knowledge Technology, Informatics Department, University of Hamburg, Hamburg, Germany
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33
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Tashani OA, Astita R, Sharp D, Johnson MI. Body mass index and distribution of body fat can influence sensory detection and pain sensitivity. Eur J Pain 2017; 21:1186-1196. [DOI: 10.1002/ejp.1019] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/11/2017] [Indexed: 12/12/2022]
Affiliation(s)
- O. A Tashani
- School of Clinical and Applied Sciences; Leeds Beckett University; UK
| | - R. Astita
- School of Clinical and Applied Sciences; Leeds Beckett University; UK
- Higher Institute of Medical Professions; Al-Bayda Libya
| | - D. Sharp
- School of Clinical and Applied Sciences; Leeds Beckett University; UK
| | - M. I Johnson
- School of Clinical and Applied Sciences; Leeds Beckett University; UK
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34
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Louca Jounger S, Christidis N, Svensson P, List T, Ernberg M. Increased levels of intramuscular cytokines in patients with jaw muscle pain. J Headache Pain 2017; 18:30. [PMID: 28243900 PMCID: PMC5328896 DOI: 10.1186/s10194-017-0737-y] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 02/15/2017] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND The aim of this study was to investigate cytokine levels in the masseter muscle, their response to experimental tooth-clenching and their relation to pain, fatigue and psychological distress in patients with temporomandibular disorders (TMD) myalgia. METHODS Forty women, 20 with TMD myalgia (Diagnostic Criteria for TMD) and 20 age-matched healthy controls participated. Intramuscular microdialysis was performed to sample masseter muscle cytokines. After 140 min (baseline), a 20-minute tooth-clenching task was performed (50% of maximal voluntary contraction force). Pain (Numeric rating scale 0-10) and fatigue (Borg's Ratings of Perceived Exertion 6-20) were assessed throughout microdialysis, while pressure-pain thresholds (PPT) were assessed before and after microdialysis. Perceived stress (PSS-10) and Trait Anxiety (STAI) were assessed before microdialysis. RESULTS The levels of IL-6, IL-7, IL-8 and IL-13 were higher in patients than controls (Mann Whitney U-test; P's < 0.05) during the entire microdialysis. IL-6, IL-8 and IL-13 changed during microdialysis in both groups (Friedman; P's < 0.05), while IL-1β, IL-7 and GM-CSF changed only in patients (P's < 0.01). IL-6 and IL-8 increased in response to tooth-clenching in both groups (Wilcoxon test; P's < 0.05), while IL-7, IL-13 and TNF increased only in patients (P's < 0.05). Patients had higher pain and fatigue than controls before and after tooth-clenching (P < 0.001), and lower PPTs before and after microdialysis (P < 0.05). There were no correlations between cytokine levels, pain or fatigue. Also, there were no differences in stress or anxiety levels between groups. CONCLUSIONS In conclusion, the masseter levels of IL-6, IL-7, IL-8 and IL-13 were elevated in patients with TMD myalgia and increased in response to tooth-clenching. Tooth-clenching increased jaw muscle pain and fatigue, but without correlations to cytokine levels. This implies that subclinical muscle inflammation may be involved in TMD myalgia pathophysiology, but that there is no direct cause-relation between inflammation and pain.
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Affiliation(s)
- S Louca Jounger
- Section for Orofacial Pain and Jaw Function, Department of Dental Medicine, Karolinska Institutet, SE 14104, Huddinge, Sweden. .,Scandinavian Center for Orofacial Neurosciences (SCON), Huddinge, Sweden.
| | - N Christidis
- Section for Orofacial Pain and Jaw Function, Department of Dental Medicine, Karolinska Institutet, SE 14104, Huddinge, Sweden.,Scandinavian Center for Orofacial Neurosciences (SCON), Huddinge, Sweden
| | - P Svensson
- Section for Orofacial Pain and Jaw Function, Department of Dental Medicine, Karolinska Institutet, SE 14104, Huddinge, Sweden.,Scandinavian Center for Orofacial Neurosciences (SCON), Huddinge, Sweden.,Section of Orofacial Pain and Jaw Function, School of Dentistry and Oral Health, Aarhus University, Vennelyst Boulevard 9, DK-8000, Aarhus C, Denmark
| | - T List
- Scandinavian Center for Orofacial Neurosciences (SCON), Huddinge, Sweden.,Faculty of Odontology, Malmö University, Malmö, Sweden
| | - M Ernberg
- Section for Orofacial Pain and Jaw Function, Department of Dental Medicine, Karolinska Institutet, SE 14104, Huddinge, Sweden.,Scandinavian Center for Orofacial Neurosciences (SCON), Huddinge, Sweden
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Lin RL, Douaud G, Filippini N, Okell TW, Stagg CJ, Tracey I. Structural Connectivity Variances Underlie Functional and Behavioral Changes During Pain Relief Induced by Neuromodulation. Sci Rep 2017; 7:41603. [PMID: 28148969 PMCID: PMC5288647 DOI: 10.1038/srep41603] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 12/23/2016] [Indexed: 12/31/2022] Open
Abstract
An increased understanding of the relationship between structural connections and functional and behavioral outcomes is an essential but under-explored topic in neuroscience. During transcranial direct current stimulation (tDCS)-induced analgesia, neuromodulation occurs through a top-down process that depends on inter-regional connections. To investigate whether variation in anatomical connectivity explains functional and behavorial outcomes during neuromodulation, we first combined tDCS and a tonic pain model with concurrent arterial spin labelling that measures cerebral perfusion related to ongoing neural activity. Left dorsolateral prefrontal cortex (L-DLPFC) tDCS induced an analgesic effect, which was explained by reduced perfusion to posterior insula and thalamus. Second, we used diffusion imaging to assess white matter structural integrity between L-DLPFC and thalamus, two key components of the neuromodulatory network. Fractional anisotropy of this tract correlated positively with functional and behavioral modulations. This suggests structural dependence by the neuromodulatory process to induce analgesia with potential relevance for patient stratification.
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Affiliation(s)
- Richard L. Lin
- Oxford Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB Centre), University of Oxford, Oxford OX1 3UH, United Kingdom
- Nuffield Division of Anaesthetics, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX1 3UH, United Kingdom
| | - Gwenaëlle Douaud
- Oxford Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB Centre), University of Oxford, Oxford OX1 3UH, United Kingdom
| | - Nicola Filippini
- Oxford Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB Centre), University of Oxford, Oxford OX1 3UH, United Kingdom
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX1 3UH, United Kingdom
| | - Thomas W. Okell
- Oxford Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB Centre), University of Oxford, Oxford OX1 3UH, United Kingdom
| | - Charlotte J. Stagg
- Oxford Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB Centre), University of Oxford, Oxford OX1 3UH, United Kingdom
- Oxford Centre for Human Brain Activity, Department of Psychiatry, University of Oxford, Oxford OX1 3UH, United Kingdom
| | - Irene Tracey
- Oxford Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB Centre), University of Oxford, Oxford OX1 3UH, United Kingdom
- Nuffield Division of Anaesthetics, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX1 3UH, United Kingdom
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Cutaneous silent period evoked in human first dorsal interosseous muscle motor units by laser stimulation. J Electromyogr Kinesiol 2016; 31:104-110. [DOI: 10.1016/j.jelekin.2016.10.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Revised: 09/28/2016] [Accepted: 10/10/2016] [Indexed: 11/27/2022] Open
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37
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Arout CA, Perrino AC, Ralevski E, Acampora G, Koretski J, Limoncelli D, Newcomb J, Petrakis IL. Effect of Intravenous Ethanol on Capsaicin-Induced Hyperalgesia in Human Subjects. Alcohol Clin Exp Res 2016; 40:1425-9. [PMID: 27218476 DOI: 10.1111/acer.13095] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 04/04/2016] [Indexed: 12/22/2022]
Abstract
BACKGROUND The objective of this study was to assess ethanol's (EtOH's) effects on capsaicin-induced hyperalgesia in healthy participants. Specifically, we investigated the change in area of capsaicin-induced hyperalgesia following 3 interventions: intravenous EtOH at 2 targeted breath alcohol concentrations (BrAC), or placebo. METHODS Eighteen participants participated in 3 test days in a randomized order. Each test day, participants received an intradermal capsaicin injection on the volar surface of the forearm, followed by either infusion of high concentration EtOH (targeted BrAC = 0.100 g/dl), low concentration EtOH (targeted BrAC = 0.040 g/dl), or placebo. The area of hyperalgesia was determined by von Frey technique at 2 time points, prior to EtOH infusion, and again when target BrAC was reached. The primary outcome was the percent change in the area of capsaicin-induced hyperalgesia. Additional outcome measures included the visual analogue scale of mood states (VAS), which was administered at each time point. RESULTS There was a marked 30% reduction in the area of capsaicin-induced hyperalgesia with infusion of a high concentration of EtOH (p < 0.05). Low concentration EtOH produced a 10% reduction in hyperalgesia area, although this finding did not reach significance. Further, participants reported significant feelings of euphoria and drowsiness at high concentrations of EtOH (p < 0.05), as measured by the VAS. CONCLUSIONS In a human model examining pain phenomena related to central sensitization, this study is the first to demonstrate that capsaicin-induced hyperalgesia is markedly attenuated by EtOH. The capsaicin experimental pain paradigm employed provides a novel approach to evaluate EtOH's effects on pain processing. The antihyperalgesic effects of EtOH observed have important clinical implications for the converging fields of substance abuse and pain medicine and may inform why patients with chronic pain often report alcohol use as a form of self-medication.
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Affiliation(s)
- Caroline A Arout
- Department of Psychiatry, Center for Translational Neuroscience of Alcoholism and VA Alcohol Research Center, Yale University School of Medicine, West Haven, Connecticut
| | - Albert C Perrino
- Department of Anesthesiology, VA Connecticut Healthcare System, Yale University School of Medicine, West Haven, Connecticut
| | - Elizabeth Ralevski
- Department of Psychiatry, Center for Translational Neuroscience of Alcoholism and VA Alcohol Research Center, Yale University School of Medicine, West Haven, Connecticut
| | - Gregory Acampora
- Department of Psychiatry, Massachusetts General Hospital, Harvard Center for Addiction Medicine, Boston, Massachusetts
| | - Julia Koretski
- Department of Psychiatry, Center for Translational Neuroscience of Alcoholism and VA Alcohol Research Center, Yale University School of Medicine, West Haven, Connecticut
| | - Diana Limoncelli
- Department of Psychiatry, Center for Translational Neuroscience of Alcoholism and VA Alcohol Research Center, Yale University School of Medicine, West Haven, Connecticut
| | - Jenelle Newcomb
- Department of Psychiatry, Center for Translational Neuroscience of Alcoholism and VA Alcohol Research Center, Yale University School of Medicine, West Haven, Connecticut
| | - Ismene L Petrakis
- Department of Psychiatry, Center for Translational Neuroscience of Alcoholism and VA Alcohol Research Center, Yale University School of Medicine, West Haven, Connecticut
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Durga P, Wudaru SR, Khambam SKR, Chandra SJ, Ramachandran G. Validation of simple and inexpensive algometry using sphygmomanometer cuff and neuromuscular junction monitor with standardized laboratory algometer. J Anaesthesiol Clin Pharmacol 2016; 32:74-9. [PMID: 27006546 PMCID: PMC4784219 DOI: 10.4103/0970-9185.173390] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Background and Aims: The availability, ergonomics and economics prohibit the routine use of algometers in clinical practice and research by the anesthesiologists. A simple bedside technique of quantitative pain measurement would enable the routine use of algometry. We proposed to validate simple pain provocation using sphygmomanometer cuff and the electric stimulation of neuromuscular junction monitor (TOF-guard, Organon Teknika) to measure pain against a standardized laboratory pressure algometer. Material and Methods: Pain detection threshold (Pdt) and pain tolerance threshold (Ptt) were measured in forty healthy volunteers of both genders, using the above three techniques. All measurements were repeated three times. The co-efficient of inter-rater reliability (or consistency) between three independent measurements obtained from each of the techniques was determined by Cronbach's co-efficient alpha (α C). The correlation between the mean Pdt and Ptt values recorded by standardized algometer and the sphygmomanometer technique and nerve stimulator technique was performed using Pearson Correlation. An r >0.5 and a two-tailed significance of <0.05 were considered as good correlation between the standardized algometer and the tested techniques. Results: There was a good inter-rater reliability (α C > 0.7) for the three techniques. There was a good correlation with r >0.65 (P < 0.001) between the measurements of standardized pressure algometer and the two techniques being tested as alternatives for algometer to measure pain. Conclusion: The sphygmomanometer cuff technique and electrical stimulation with the peripheral nerve stimulator to measure pain threshold and tolerance provide a simple, efficient, repeatable measure of pain intensity and can be used as suitable alternatives to standard algometers.
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Affiliation(s)
- Padmaja Durga
- Department of Anesthesiology and Intensive Care, Nizam's Institute of Medical Sciences, Hyderabad, Andhra Pradesh, India
| | - Sreedhar Reddy Wudaru
- Department of Anesthesiology and Intensive Care, Nizam's Institute of Medical Sciences, Hyderabad, Andhra Pradesh, India
| | - Sunil Kumar Reddy Khambam
- Department of Clinical Pharmacology and Medical Research, Nizam's Institute of Medical Sciences, Hyderabad, Andhra Pradesh, India
| | - Shobha Jagadish Chandra
- Department of Clinical Pharmacology and Medical Research, Nizam's Institute of Medical Sciences, Hyderabad, Andhra Pradesh, India
| | - Gopinath Ramachandran
- Department of Anesthesiology and Intensive Care, Nizam's Institute of Medical Sciences, Hyderabad, Andhra Pradesh, India
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Wassinger CA, Rich D, Cameron N, Clark S, Davenport S, Lingelbach M, Smith A, Baxter GD, Davidson J. Cervical & thoracic manipulations: Acute effects upon pain pressure threshold and self-reported pain in experimentally induced shoulder pain. ACTA ACUST UNITED AC 2016; 21:227-32. [DOI: 10.1016/j.math.2015.08.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 07/08/2015] [Accepted: 08/18/2015] [Indexed: 02/02/2023]
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Taneja A, Oosterholt SP, Danhof M, Della Pasqua O. Biomarker exposure-response relationships as the basis for rational dose selection: Lessons from a simulation exercise using a selective COX-2 inhibitor. J Clin Pharmacol 2015; 56:609-21. [DOI: 10.1002/jcph.629] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 08/26/2015] [Indexed: 11/12/2022]
Affiliation(s)
- Amit Taneja
- Division of Pharmacology; Leiden Academic Centre for Drug Research; Leiden University; Leiden The Netherlands
| | - Sean P. Oosterholt
- Division of Pharmacology; Leiden Academic Centre for Drug Research; Leiden University; Leiden The Netherlands
| | - Meindert Danhof
- Division of Pharmacology; Leiden Academic Centre for Drug Research; Leiden University; Leiden The Netherlands
| | - Oscar Della Pasqua
- Division of Pharmacology; Leiden Academic Centre for Drug Research; Leiden University; Leiden The Netherlands
- Clinical Pharmacology & Therapeutics; University College London; London UK
- Clinical Pharmacology Modelling & Simulation; GlaxoSmithKline; Stockley Park UK
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Saxena I, Kumar M, Barath AS, Verma A, Garg S, Kumar M. Effect of Age on Response to Experimental Pain in Normal Indian Males. J Clin Diagn Res 2015; 9:CC05-8. [PMID: 26500901 DOI: 10.7860/jcdr/2015/15385.6516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 08/17/2015] [Indexed: 11/24/2022]
Abstract
BACKGROUND AND OBJECTIVES Response to experimental pain depends on the nature of the pain stimulus, as well as on gender, racial, cultural and socioeconomic factors. This study investigates the effect of age on pain sensitivity and cardiovascular reactivity produced by experimental pain. We have also compared the values of body mass index (BMI) and resting blood pressure of volunteers with the normal values. MATERIALS AND METHODS The study was conducted on 83 Indian males of different age groups. The volunteers were divided into 4 groups: Children, Young Adults, Middle-Aged Adults and Old Adults; and their basal parameters (BMI, resting pulse and blood pressure) were recorded. Selected volunteers were subjected to cold pressor task (CPT). Pain sensitivity (PS) (pain threshold, tolerance and pain rating on a visual analog scale) and cardiovascular reactivity (CVR) (increase in pulse and blood pressure) were recorded. RESULTS Many volunteers had abnormal values of BMI and resting blood pressure and had to be excluded from the study. PS and CVR between different groups were compared by one-way ANOVA. Significant differences in PS were observed, with highest pain sensitivity in Children and lowest in Old Adults. No significant differences were observed in the CVR. CONCLUSION The high numbers of volunteers with abnormal basal parameters (BMI and resting blood pressure) show an urgent need to educate the general public about the dangers and risk factors of obesity and hypertension. Less exposure of children to painful encounters may be responsible for their high pain sensitivity while higher values of resting blood pressure and decreased sensitivity of the sensory systems with advancing age may be responsible for the hypoalgesia observed in old adults.
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Affiliation(s)
- Indu Saxena
- Assistant Professor, Deparment of Biochemistry, AIIMS Jodhpur, Rajasthan, India
| | - Manoj Kumar
- Professor, Department of Physiology, TMMC & RC , Moradabad, Uttar Predesh, India
| | | | - Anjali Verma
- Demonstrator, Department of Physiology, TMMC & RC , Moradabad, Uttar Predesh, India
| | - Sumit Garg
- Assistant Professor, Department of Physiology, SIMS , Hapur, Uttar Predesh, India
| | - Manoj Kumar
- Social Worker, Department of Community Medicine, TMMC & RC Moradabad, Uttar Predesh, India
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Luvisetto S, Gazerani P, Cianchetti C, Pavone F. Botulinum Toxin Type a as a Therapeutic Agent against Headache and Related Disorders. Toxins (Basel) 2015; 7:3818-44. [PMID: 26404377 PMCID: PMC4591645 DOI: 10.3390/toxins7093818] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 09/15/2015] [Indexed: 12/24/2022] Open
Abstract
Botulinum neurotoxin A (BoNT/A) is a toxin produced by the naturally-occurring Clostridium botulinum that causes botulism. The potential of BoNT/A as a useful medical intervention was discovered by scientists developing a vaccine to protect against botulism. They found that, when injected into a muscle, BoNT/A causes a flaccid paralysis. Following this discovery, BoNT/A has been used for many years in the treatment of conditions of pathological muscle hyperactivity, like dystonias and spasticities. In parallel, the toxin has become a “glamour” drug due to its power to ward off facial wrinkles, particularly frontal, due to the activity of the mimic muscles. After the discovery that the drug also appeared to have a preventive effect on headache, scientists spent many efforts to study the potentially-therapeutic action of BoNT/A against pain. BoNT/A is effective at reducing pain in a number of disease states, including cervical dystonia, neuropathic pain, lower back pain, spasticity, myofascial pain and bladder pain. In 2010, regulatory approval for the treatment of chronic migraine with BoNT/A was given, notwithstanding the fact that the mechanism of action is still not completely elucidated. In the present review, we summarize experimental evidence that may help to clarify the mechanisms of action of BoNT/A in relation to the alleviation of headache pain, with particular emphasis on preclinical studies, both in animals and humans. Moreover, we summarize the latest clinical trials that show evidence on headache conditions that may obtain benefits from therapy with BoNT/A.
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Affiliation(s)
- Siro Luvisetto
- National Research Council (CNR) of Italy, Institute of Cell Biology and Neurobiology, Roma 00185, Italy.
| | - Parisa Gazerani
- Center for Sensory-Motor Interaction, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg East 9220, Denmark.
| | - Carlo Cianchetti
- Former Professor of Child & Adolescent Neuropsychiatry, University of Cagliari, Cagliari 09124, Italy.
| | - Flaminia Pavone
- National Research Council (CNR) of Italy, Institute of Cell Biology and Neurobiology, Roma 00185, Italy.
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Kardouni JR, Shaffer SW, Pidcoe PE, Finucane SD, Cheatham SA, Michener LA. Immediate changes in pressure pain sensitivity after thoracic spinal manipulative therapy in patients with subacromial impingement syndrome: A randomized controlled study. ACTA ACUST UNITED AC 2015; 20:540-6. [DOI: 10.1016/j.math.2014.12.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 11/26/2014] [Accepted: 12/10/2014] [Indexed: 10/24/2022]
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A review of morphine and morphine-6-glucuronide’s pharmacokinetic–pharmacodynamic relationships in experimental and clinical pain. Eur J Pharm Sci 2015; 74:45-62. [DOI: 10.1016/j.ejps.2015.03.020] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 01/31/2015] [Accepted: 03/23/2015] [Indexed: 01/10/2023]
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Gram M, Graversen C, Olesen AE, Drewes AM. Machine learning on encephalographic activity may predict opioid analgesia. Eur J Pain 2015; 19:1552-61. [PMID: 26095578 DOI: 10.1002/ejp.734] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/23/2015] [Indexed: 11/06/2022]
Abstract
BACKGROUND Opioids are used for the treatment of pain. However, 30-50% of patients have insufficient effect to the opioid initially selected by the physician, and there is an urgent need for biomarkers to select responders to the most appropriate drug. Since opioids mediate their effect in the central nervous system, this study aimed to investigate if electroencephalography (EEG) during rest or pain before treatment could predict the analgesic response. METHODS EEG from 62 channels was recorded in volunteers during rest and tonic pain (cold pressor test). Morphine (30 mg) or placebo was then administered, and the pain test repeated 60 min after. Washout period between drugs was 7 days. Based on pain ratings, subjects were stratified into responders and non-responders. Spectral analysis was performed on the EEG. Conventional statistics on group basis were used and, furthermore, the most discriminative EEG features were subjected to support vector machine classification to predict the response for the individual subjects. RESULTS Conventional statistics on the frequency bands revealed no differences between responders and non-responders. On the individual basis, no differences between groups were found using resting EEG. However, EEG during cold pain was able to classify responders with an accuracy of 72% (p = 0.01) and the result was reproducible using baseline data from both study days. CONCLUSIONS Machine learning based on EEG before treatment enabled separation between responders and non-responders. This study represents the first step towards the prediction of opioid analgesia based on EEG features prior to drug administration, and advocates for the use of machine learning in future studies.
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Affiliation(s)
- M Gram
- Mech-Sense, Department of Gastroenterology and Hepatology, Aalborg University Hospital, Denmark
| | - C Graversen
- Mech-Sense, Department of Gastroenterology and Hepatology, Aalborg University Hospital, Denmark
| | - A E Olesen
- Mech-Sense, Department of Gastroenterology and Hepatology, Aalborg University Hospital, Denmark.,Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - A M Drewes
- Mech-Sense, Department of Gastroenterology and Hepatology, Aalborg University Hospital, Denmark.,Clinical Institute, Aalborg University Hospital, Denmark
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Horn-Hofmann C, Büscher P, Lautenbacher S, Wolstein J. The effect of nonrecurring alcohol administration on pain perception in humans: a systematic review. J Pain Res 2015; 8:175-87. [PMID: 25960674 PMCID: PMC4412487 DOI: 10.2147/jpr.s79618] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Purpose Alcohol is believed to have pain-dampening effects and is often used as self-medication by persons with pain problems; however, experimental evidence confirming this effect is scarce. We conducted a systematic review of experimental studies on the effects of nonrecurring alcohol administration on pain perception in healthy human subjects and the underlying mechanisms. Method Three databases (PubMed, PsycINFO, and Web of Science) were searched for relevant studies using a predefined algorithm. In a next step, irrelevant articles were excluded by screening titles and abstracts. Finally, articles were checked regarding a set of methodological criteria; only publications meeting these criteria were selected for this review. A total of 14 experimental studies were identified. Results Overall, most of the studies were able to show a pain-dampening effect of alcohol. However, many of them had methodological shortcomings (eg, lack of placebo control, insufficient blinding, or very small sample sizes). In addition, comparability is limited due to considerable variations in alcohol administration and pain measurement. More importantly, potential mechanisms of action and moderating variables have scarcely been investigated. Conclusion Despite the frequent use of alcohol as self-medication by persons with pain problems, there are to date only a few experimental investigations of alcohol effects on pain perceptions. The results of these studies suggest that alcohol does in fact have pain-dampening effects. However, the mechanisms implicated in these effects are still unknown, and experimental research has been limited to pain-free subjects. Future research should provide more knowledge about alcohol effects on pain, especially in chronic pain patients.
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Affiliation(s)
- Claudia Horn-Hofmann
- Pathopsychology, University of Bamberg, Bamberg, Germany ; Physiological Psychology, University of Bamberg, Bamberg, Germany
| | | | | | - Jörg Wolstein
- Pathopsychology, University of Bamberg, Bamberg, Germany
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Malver LP, Brokjaer A, Staahl C, Graversen C, Andresen T, Drewes AM. Electroencephalography and analgesics. Br J Clin Pharmacol 2015; 77:72-95. [PMID: 23593934 DOI: 10.1111/bcp.12137] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 03/05/2013] [Indexed: 11/29/2022] Open
Abstract
To assess centrally mediated analgesic mechanisms in clinical trials with pain patients, objective standardized methods such as electroencephalography (EEG) has many advantages. The aim of this review is to provide the reader with an overview of present findings in analgesics assessed with spontaneous EEG and evoked brain potentials (EPs) in humans. Furthermore, EEG methodologies will be discussed with respect to translation from animals to humans and future perspectives in predicting analgesic efficacy. We searched PubMed with MeSH terms 'analgesics', 'electroencephalography' and 'evoked potentials' for relevant articles. Combined with a search in their reference lists 15 articles on spontaneous EEG and 55 papers on EPs were identified. Overall, opioids produced increased activity in the delta band in the spontaneous EEG, but increases in higher frequency bands were also seen. The EP amplitudes decreased in the majority of studies. Anticonvulsants used as analgesics showed inconsistent results. The N-methyl-D-aspartate receptor antagonist ketamine showed an increase in the theta band in spontaneous EEG and decreases in EP amplitudes. Tricyclic antidepressants increased the activity in the delta, theta and beta bands in the spontaneous EEG while EPs were inconsistently affected. Weak analgesics were mainly investigated with EPs and a decrease in amplitudes was generally observed. This review reveals that both spontaneous EEG and EPs are widely used as biomarkers for analgesic drug effects. Methodological differences are common and a more uniform approach will further enhance the value of such biomarkers for drug development and prediction of treatment response in individual patients.
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Affiliation(s)
- Lasse Paludan Malver
- Mech-Sense, Department of Gastroenterology & Hepatology, Aalborg University Hospital, Aalborg, Denmark
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de Oliveira AM, de Araújo AF, Lyra Lemos RP, Conserva LM, de Souza Ferro JN, Barreto E. Antinociceptive and anti-inflammatory activity of the siaresinolic acid, a triterpene isolated from the leaves of Sabicea grisea Cham. & Schltdl. var. grisea. J Nat Med 2015; 69:232-40. [DOI: 10.1007/s11418-014-0883-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 12/25/2014] [Indexed: 10/24/2022]
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Abstract
Undertreatment of pain (oligoanalgesia) in the emergency department is common, and it negatively impacts patient care. Both failure of appropriate pain assessment and the potential for unsafe analgesic use contribute to the problem. As a result, achieving satisfactory analgesia while minimizing side effects remains particularly challenging for emergency physicians, both in the emergency department and after a patient is discharged. Improvements in rapid pain assessment and in evaluation of noncommunicative populations may result in a better estimation of which patients require analgesia and how much pain is present. New formulations of available treatments, such as rapidly absorbed, topical, or intranasal nonsteroidal anti-inflammatory drug formulations or intranasal opioids, may provide effective analgesia with an improved risk-benefit profile. Other pharmacological therapies have been shown to be effective for certain pain modalities, such as the use of antidepressants for musculoskeletal pain, γ-aminobutyric acid agonists for neuropathic and postsurgical pain, antipsychotics for headache, and topical capsaicin for neuropathic pain. Nonpharmacological methods of pain control include the use of electrical stimulation, relaxation therapies, psychosocial/manipulative therapies, and acupuncture. Tailoring of available treatment options to specific pain modalities, as well as improvements in pain assessment, treatment options, and formulations, may improve pain control in the emergency department setting and beyond.
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Affiliation(s)
- Charles V Pollack
- Professor, Department of Emergency Medicine, Perelman School of Medicine of the University of Pennsylvania, and Chairman, Department of Emergency Medicine, Pennsylvania Hospital , Philadelphia, PA , USA
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Immediate effects of spinal manipulation on nitric oxide, substance P and pain perception. ACTA ACUST UNITED AC 2014; 19:411-7. [DOI: 10.1016/j.math.2014.02.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 02/15/2014] [Accepted: 02/23/2014] [Indexed: 11/18/2022]
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