Sucrose and naltrexone prevent increased pain sensitivity and impaired long-term memory induced by repetitive neonatal noxious stimulation: Role of BDNF and β-endorphin.

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Nuseir, Khawla Q; Alzoubi, Karem H; Alhusban, Ahmed; Bawaane, Areej; Al-Azzani, Mohammed; Khabour, Omar F

2017-10-01

Pain in neonates is associated with short and long-term adverse outcomes. Data demonstrated that long-term consequences of untreated pain are linked to the plasticity of the neonate's brain. Sucrose is effective and safe for reducing painful procedures from single events. However, the mechanism of sucrose-induced analgesia is not fully understood. The role of the opioid system in this analgesia using the opioid receptor antagonist Naltrexone was investigated, plus the long-term effects on learning and memory formation during adulthood. Pain was induced in rat pups via needle pricks of the paws. Sucrose solution and/or naltrexone were administered before the pricks. All treatments started on day one of birth and continued for two weeks. At the end of 8weeks, behavioral studies were conducted to test spatial learning and memory using radial arm water maze (RAWM), and pain threshold via foot-withdrawal response to a hot plate. The hippocampus was dissected; levels of brain derived neurotrophic factor (BDNF) and endorphins were assessed using ELISA. Acute repetitive neonatal pain increased pain sensitivity later in life, while naltrexone with sucrose decreased pain sensitivity. Naltrexone and/or sucrose prevented neonatal pain induced impairment of long-term memory, while neonatal pain decreased levels of BDNF in the hippocampus; this decrease was averted by sucrose and naltrexone. Sucrose with naltrexone significantly increased β-endorphin levels in noxiously stimulated rats. In conclusion, naltrexone and sucrose can reverse increased pain sensitivity and impaired long-term memory induced by acute repetitive neonatal pain probably by normalizing BDNF expression and increasing β-endorphin levels. Copyright © 2017 Elsevier Inc. All rights reserved.

Increased pain sensitivity is not associated with electrodiagnostic findings in women with carpal tunnel syndrome.

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de la Llave-Rincón, Ana Isabel; Fernández-de-las-Peñas, César; Laguarta-Val, Sofia; Alonso-Blanco, Cristina; Martínez-Perez, Almudena; Arendt-Nielsen, Lars; Pareja, Juan A

2011-01-01

To determine the differences in widespread pressure pain and thermal hypersensitivity in women with minimal, moderate, and severe carpal tunnel syndrome (CTS) and healthy controls. A total of 72 women with CTS (19 with minimal, 18 with moderate, and 35 with severe) and 19 healthy age-matched women participated. Pressure pain thresholds were bilaterally assessed over the median, ulnar, and radial nerves, the C5 to C6 zygapophyseal joint, the carpal tunnel, and the tibialis anterior muscle. In addition, warm and cold detection thresholds and heat and cold pain thresholds were bilaterally assessed over the carpal tunnel and the thenar eminence. All outcome parameters were assessed by an assessor blinded to the participant's condition. No significant differences in pain parameters among patients with minimal, moderate, and severe CTS were found. The results showed that PPT were significantly decreased bilaterally over the median, ulnar, and radial nerve trunks, the carpal tunnel, C5 to C6 zygapophyseal joint, and the tibialis anterior muscle in patients with minimal, moderate, or severe CTS as compared with healthy controls (all, P<0.001). In addition, patients with CTS also showed lower heat pain threshold and reduced cold pain threshold compared with controls (P<0.001). No significant sensory differences between minimal, moderate, or severe CTS were found. The similar widespread pressure and thermal hypersensitivity in patients with minimal, moderate, or severe CTS and pain intensity suggests that increased pain sensitivity is not related to electrodiagnostic findings.

Psychological Distress and Widespread Pain Contribute to the Variance of the Central Sensitization Inventory : A Cross-Sectional Study in Patients with Chronic Pain

NARCIS (Netherlands)

van Wilgen, Cornelis P.; Vuijk, Pieter J.; Kregel, Jeroen; Voogt, Lennard; Meeus, Mira; Descheemaeker, Filip; Keizer, Doeke; Nijs, Jo

2018-01-01

Objectives: Central sensitization (CS) implies increased sensitivity of the nervous system, resulting in increased pain sensitivity as well as widespread pain. Recently, the Central Sensitization Inventory (CSI) was developed to assess symptoms of CS and central sensitivity syndromes. The aim of

Pain increases during sympathetic arousal in patients with complex regional pain syndrome.

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Drummond, P D; Finch, P M; Skipworth, S; Blockey, P

2001-10-09

To investigate the effect of sympathetic arousal on pain and vasomotor responses in healthy control subjects and patients with complex regional pain syndrome (CRPS), and to determine whether pain increases in patients with particular symptoms. In experiments 1 and 2, capsaicin was applied to the forearm of 24 healthy subjects to induce thermal hyperalgesia. Vascular responses were monitored and subjects rated thermal hyperalgesia before and after being startled (experiment 1), and before, during, and after mental arithmetic, breath holding, forehead cooling, the Valsalva maneuver, and a cold pressor test in experiment 2. In a third experiment, sensitivity to heat, cold, and mechanical stimulation was investigated in 61 patients with CRPS. Pain ratings and vascular and electrodermal responses were recorded after patients were startled and during forehead cooling. In experiment 1, thermal hyperalgesia decreased in healthy control subjects after they were startled, and digital blood vessels constricted symmetrically. In experiment 2, thermal hyperalgesia decreased during and after other forms of sympathetic arousal. However, in experiment 3, ratings of clinical pain increased during forehead cooling or after being startled in over 70% of patients with CRPS. Pain increased most consistently during forehead cooling in patients with cold allodynia or punctate allodynia. Digital blood vessels constricted more intensely on the symptomatic than the nonsymptomatic side in patients with CRPS during sympathetic arousal. Normal inhibitory influences on pain during sympathetic arousal are compromised in the majority of patients with CRPS. The augmented vasoconstrictor response in the symptomatic limb during sympathetic arousal is consistent with adrenergic supersensitivity. An adrenergic sensitivity in nociceptive afferents might contribute to pain and hyperalgesia during sympathetic arousal in certain patients with CRPS.

A pain in the bud? Implications of cross-modal sensitivity for pain experience.

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Perkins, Monica; de Bruyne, Marien; Giummarra, Melita J

2016-11-01

There is growing evidence that enhanced sensitivity to painful clinical procedures and chronic pain are related to greater sensitivity to other sensory inputs, such as bitter taste. We examined cross-modal sensitivities in two studies. Study 1 assessed associations between bitter taste sensitivity, pain tolerance, and fear of pain in 48 healthy young adults. Participants were classified as non-tasters, tasters and super-tasters using a bitter taste test (6-n-propythiouracil; PROP). The latter group had significantly higher fear of pain (Fear of Pain Questionnaire) than tasters (p=.036, effect size r = .48). There was only a trend for an association between bitter taste intensity ratings and intensity of pain at the point of pain tolerance in a cold pressor test (p=.04). In Study 2, 40 healthy young adults completed the Adolescent/Adult Sensory Profile before rating intensity and unpleasantness of innocuous (33 °C), moderate (41 °C), and high intensity (44 °C) thermal pain stimulations. The sensory-sensitivity subscale was positively correlated with both intensity and unpleasantness ratings. Canonical correlation showed that only sensitivity to audition and touch (not taste/smell) were associated with intensity of moderate and high (not innocuous) thermal stimuli. Together these findings suggest that there are cross-modal associations predominantly between sensitivity to exteroceptive inputs (i.e., taste, touch, sound) and the affective dimensions of pain, including noxious heat and intolerable cold pain, in healthy adults. These cross-modal sensitivities may arise due to greater psychological aversion to salient sensations, or from shared neural circuitry for processing disparate sensory modalities.

Neural and psychosocial mechanisms of pain sensitivity in fibromyalgia.

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English, Brian

2014-06-01

Fibromyalgia is a chronic musculoskeletal pain disorder that affects an estimated 5 million adults in the U.S. The hallmark is burning, searing, tingling, shooting, stabbing, deep aching, or sharp pain. Fibromyalgia is generally considered to be a "central sensitivity syndrome" where central sensitization is regarded as the cause of pain in its own right. Nonetheless, the case continues to be made that all central and spatially distributed peripheral components of fibromyalgia pain would fade if the peripheral generators could be silenced. Although neural mechanisms are clearly important in pain sensitivity, cognitive and social mechanisms also need to be considered. The aim of this review is to examine four mechanisms responsible for heightened pain sensitivity in fibromyalgia: peripheral sensitization, central sensitization, cognitive-emotional sensitization, and interpersonal sensitization. The purpose of framing the review in terms of pain sensitivity in fibromyalgia is to highlight that different mechanisms of sensitization are appropriately regarded as intervening variables when it comes to understanding individual differences in the experience of pain. The paper concludes by considering the implications of the findings of the review for explanations of fibromyalgia pain by nurses working in multidisciplinary teams. The trend appears to be able to explain the cause of fibromyalgia pain in terms of sensitization per se. The recommended alternative is to explain fibromyalgia pain in terms of changes in pain sensitivity and the role of underlying neural and psychosocial mechanisms. Copyright © 2014 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

Perinatal maternal stress and serotonin signaling: effects on pain sensitivity in offspring.

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Knaepen, Liesbeth; Pawluski, Jodi L; Patijn, Jacob; van Kleef, Maarten; Tibboel, Dick; Joosten, Elbert A

2014-07-01

It has been estimated that 20% of pregnant women are facing perinatal stress and depression. Perinatal maternal stress has been shown to increase pain sensitivity in offspring. For the treatment of their depressive symptoms, pregnant women are frequently prescribed selective serotonin reuptake inhibitors (SSRIs). Since the descending pain inhibitory circuit matures perinatally, perinatal SSRI exposure has been shown to affect pain sensitivity in offspring. In the present review, we summarize experimental and clinical evidence for the effect of perinatal maternal stress and SSRI exposure on pain sensitivity in offspring. Both experimental and clinical studies show the effect of perinatal maternal stress on regulation of the hypothalamic-pituitary-adrenal (HPA) system and the serotonin pain inhibitory system. Alterations in these two systems likely underlie long-term alterations in the development of pain sensitivity. This review sheds light on the effect of perinatal maternal stress and treatment with SSRIs on offspring pain sensitivity, in relation to the developing HPA system and 5-HT signaling. © 2013 Wiley Periodicals, Inc.

Does catastrophic thinking enhance oesophageal pain sensitivity?

DEFF Research Database (Denmark)

Martel, M O; Olesen, A E; Jørgensen, D

2016-01-01

that catastrophic thinking exerts an influence on oesophageal pain sensitivity, but not necessarily on the magnitude of acid-induced oesophageal sensitization. WHAT DOES THIS STUDY ADD?: Catastrophizing is associated with heightened pain sensitivity in the oesophagus. This was substantiated by assessing responses...

Enhanced short-term sensitization of facial compared with limb heat pain.

Science.gov (United States)

Schmidt, Katharina; Schunke, Odette; Forkmann, Katarina; Bingel, Ulrike

2015-08-01

Habituation and sensitization are important features of individual sensitivity to repetitive noxious stimulation and have been investigated in numerous studies. However, it is unclear whether these phenomena vary depending on the site of stimulation. Here we compared short-term and long-term effects of painful heat stimulation on the forehead and limb using an established longitudinal heat pain paradigm performed over 8 consecutive days in 36 healthy volunteers. Participants were randomized into 2 groups; participants received repetitive heat pain stimulation either on the left volar forearm or on the left side of the forehead. Our data show a comparable degree of habituation over the course of 8 days in both groups. However, participants in the trigeminal stimulation group exhibited stronger within-session sensitization (indexed by a higher within-session increase in pain intensity ratings) than those who received the forearm stimulation. Furthermore, over the course of the experiment we found a correlation between habituation and anxiety, showing less habituation in participants with higher trait anxiety scores. Our findings are in line with somatotopic differences in response to painful stimulation and a higher proneness of trigeminal pain to sensitization processes, which might be explained by the biological relevance of the head and facial area for vital functions. The contribution of this sensitivity to the development and maintenance of clinical facial pain and headache disorders warrants further investigation. This study uses psychophysical methods to evaluate the differences in long-term habituation and short-term sensitization to heat pain between the trigeminal and spinal systems. We found stronger sensitization for trigeminal compared with nociceptive stimuli on the forearm. The contribution of this sensitivity to clinical pain states warrants further investigation. Copyright © 2015 American Pain Society. Published by Elsevier Inc. All rights reserved.

Effects of neonatal pain, stress and their interrelation on pain sensitivity in later life in male rats.

Science.gov (United States)

Butkevich, Irina P; Mikhailenko, Viktor A; Vershinina, Elena A; Aloisi, Anna Maria

2016-08-31

Neonatal pain and stress induce long-term changes in pain sensitivity. Therefore their interrelation is a topical subject of clinical and basic research. The present study investigated the effects of inflammatory peripheral pain and stress of maternal deprivation (MD)-isolation in 1-2- and 7-8-day-old Wistar rats (P1,2 and P7,8 respectively, ages comparable to preterm and full-term human babies) on basal pain and pain sensitivity in conditions of inflammatory pain (formalin test) during adolescence. The neonatal impacts were: pain (formalin injection, FOR in the paw), stress (a short 60-min MD), or pain+stress combination (FOR+MD), and appropriate controls. We found that stress of short-term maternal deprivation-isolation and inflammatory pain on P1,2 and P7,8 significantly increased the vulnerability of the nociceptive system to inflammatory pain. Maternal deprivation-isolation on P1,2 as compared with a similar impact on P7,8 had a greater effect on pain sensitivity of the adolescent rats, but the influence of early pain was independent of the injury age. Only adolescent rats with an early combination of pain and maternal deprivation-isolation showed hypoalgesia in the hot plate (HP) test. However licking duration (reflecting pain sensitivity) in these rats did not exceed licking duration in animals exposed only to maternal deprivation-isolation or pain. This study adds new data to the growing body of work demonstrating that early noxious impacts have long-term consequences for the functional activity of the nociceptive system. Our new findings may help to understand the impact of pain and maternal separation in the neonatal intensive care unit.

Pain sensitivity profiles in patients with advanced knee osteoarthritis

Science.gov (United States)

Frey-Law, Laura A.; Bohr, Nicole L.; Sluka, Kathleen A.; Herr, Keela; Clark, Charles R.; Noiseux, Nicolas O.; Callaghan, John J; Zimmerman, M Bridget; Rakel, Barbara A.

2016-01-01

The development of patient profiles to subgroup individuals on a variety of variables has gained attention as a potential means to better inform clinical decision-making. Patterns of pain sensitivity response specific to quantitative sensory testing (QST) modality have been demonstrated in healthy subjects. It has not been determined if these patterns persist in a knee osteoarthritis population. In a sample of 218 participants, 19 QST measures along with pain, psychological factors, self-reported function, and quality of life were assessed prior to total knee arthroplasty. Component analysis was used to identify commonalities across the 19 QST assessments to produce standardized pain sensitivity factors. Cluster analysis then grouped individuals that exhibited similar patterns of standardized pain sensitivity component scores. The QST resulted in four pain sensitivity components: heat, punctate, temporal summation, and pressure. Cluster analysis resulted in five pain sensitivity profiles: a “low pressure pain” group, an “average pain” group, and three “high pain” sensitivity groups who were sensitive to different modalities (punctate, heat, and temporal summation). Pain and function differed between pain sensitivity profiles, along with sex distribution; however no differences in OA grade, medication use, or psychological traits were found. Residualizing QST data by age and sex resulted in similar components and pain sensitivity profiles. Further, these profiles are surprisingly similar to those reported in healthy populations suggesting that individual differences in pain sensitivity are a robust finding even in an older population with significant disease. PMID:27152688

Sensitization of the Nociceptive System in Complex Regional Pain Syndrome

Science.gov (United States)

Diedrichs, Carolina; Baron, Ralf; Gierthmühlen, Janne

2016-01-01

Background Complex regional pain syndrome type I (CRPS-I) is characterized by sensory, motor and autonomic abnormalities without electrophysiological evidence of a nerve lesion. Objective Aims were to investigate how sensory, autonomic and motor function change in the course of the disease. Methods 19 CRPS-I patients (17 with acute, 2 with chronic CRPS, mean duration of disease 5.7±8.3, range 1–33 months) were examined with questionnaires (LANSS, NPS, MPI, Quick DASH, multiple choice list of descriptors for sensory, motor, autonomic symptoms), motor and autonomic tests as well as quantitative sensory testing according to the German Research Network on Neuropathic Pain at two visits (baseline and 36±10.6, range 16–53 months later). Results CRPS-I patients had an improvement of sudomotor and vasomotor function, but still a great impairment of sensory and motor function upon follow-up. Although pain and mechanical detection improved upon follow-up, thermal and mechanical pain sensitivity increased, including the contralateral side. Increase in mechanical pain sensitivity and loss of mechanical detection were associated with presence of ongoing pain. Conclusions The results demonstrate that patients with CRPS-I show a sensitization of the nociceptive system in the course of the disease, for which ongoing pain seems to be the most important trigger. They further suggest that measured loss of function in CRPS-I is due to pain-induced hypoesthesia rather than a minimal nerve lesion. In conclusion, this article gives evidence for a pronociceptive pain modulation profile developing in the course of CRPS and thus helps to assess underlying mechanisms of CRPS that contribute to the maintenance of patients’ pain and disability. PMID:27149519

Sensitization of the Nociceptive System in Complex Regional Pain Syndrome.

Directory of Open Access Journals (Sweden)

Maren Reimer

Full Text Available Complex regional pain syndrome type I (CRPS-I is characterized by sensory, motor and autonomic abnormalities without electrophysiological evidence of a nerve lesion.Aims were to investigate how sensory, autonomic and motor function change in the course of the disease.19 CRPS-I patients (17 with acute, 2 with chronic CRPS, mean duration of disease 5.7±8.3, range 1-33 months were examined with questionnaires (LANSS, NPS, MPI, Quick DASH, multiple choice list of descriptors for sensory, motor, autonomic symptoms, motor and autonomic tests as well as quantitative sensory testing according to the German Research Network on Neuropathic Pain at two visits (baseline and 36±10.6, range 16-53 months later.CRPS-I patients had an improvement of sudomotor and vasomotor function, but still a great impairment of sensory and motor function upon follow-up. Although pain and mechanical detection improved upon follow-up, thermal and mechanical pain sensitivity increased, including the contralateral side. Increase in mechanical pain sensitivity and loss of mechanical detection were associated with presence of ongoing pain.The results demonstrate that patients with CRPS-I show a sensitization of the nociceptive system in the course of the disease, for which ongoing pain seems to be the most important trigger. They further suggest that measured loss of function in CRPS-I is due to pain-induced hypoesthesia rather than a minimal nerve lesion. In conclusion, this article gives evidence for a pronociceptive pain modulation profile developing in the course of CRPS and thus helps to assess underlying mechanisms of CRPS that contribute to the maintenance of patients' pain and disability.

Thermal and pressure pain sensitivity in patients with unilateral shoulder pain: comparison of involved and uninvolved sides.

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Coronado, Rogelio A; Kindler, Lindsay L; Valencia, Carolina; George, Steven Z

2011-03-01

Cross-sectional. In the examination of patients with unilateral shoulder pain, pain provocation testing to compare the involved and uninvolved sides has been considered useful. However, side-to-side comparisons of experimental pain sensitivity in patients with unilateral shoulder pain are not widely reported in the literature. To compare experimental pain sensitivity between the involved and uninvolved sides in patients with unilateral shoulder pain. In consecutive patients seeking operative treatment for shoulder pain, sensitivity measures of bilateral pressure pain threshold at the shoulder and forearm, and thermal pain threshold, tolerance, and temporal summation at the forearm, were examined. Pressure sensitivity was tested with a Fischer pressure algometer, and thermal sensitivity with a computer-controlled Medoc neurosensory analyzer. The involved and uninvolved sides were compared with an analysis of variance. Influence of sex and location of testing were considered as covariates in the analysis. Fifty-nine consecutively recruited participants completed experimental pain sensitivity testing. Participants reported significantly lower pressure pain thresholds in the involved side compared to the uninvolved side (F1,56 = 4.96, P = .030). In addition, female compared to male participants demonstrated lower pressure pain thresholds in the bilateral shoulder regions (F1,56 = 10.84, P = .002). There was no difference in thermal pain sensitivity between sides. Average clinical pain intensity was negatively correlated with pressure pain threshold at the involved local site (r = -0.284, P = .029), indicating an influence of clinical pain intensity on local pressure pain. The results of this study provide evidence for higher experimental pressure pain sensitivity in the involved side of patients with unilateral shoulder pain and no difference between sides for thermal pain sensitivity. Females demonstrated higher pain sensitivity than males to pressure stimuli at the

Muscular heat and mechanical pain sensitivity after lengthening contractions in humans and animals.

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Queme, Fernando; Taguchi, Toru; Mizumura, Kazue; Graven-Nielsen, Thomas

2013-11-01

Mechanical sensitivity of muscle nociceptors was previously shown to increase 2 days after lengthening contractions (LC), but heat sensitivity was not different despite nerve growth factor (NGF) being upregulated in the muscle during delayed-onset muscle soreness (DOMS). The discrepancy of these results and lack of other reports drove us to assess heat sensitivity during DOMS in humans and to evaluate the effect of NGF on the heat response of muscle C-fibers. Pressure pain thresholds and pain intensity scores to intramuscular injection of isotonic saline at 48°C and capsaicin were recorded in humans after inducing DOMS. The response of single unmyelinated afferents to mechanical and heat stimulations applied to their receptive field was recorded from muscle-nerve preparations in vitro. In humans, pressure pain thresholds were reduced but heat and capsaicin pain responses were not increased during DOMS. In rats, the mechanical but not the heat sensitivity of muscle C-fibers was increased in the LC group. NGF applied to the receptive field facilitated the heat sensitivity relative to the control. The absence of facilitated heat sensitivity after LC, despite the NGF sensitization, may be explained if the NGF concentration produced after LC is not sufficient to sensitize nociceptor response to heat. This article presents new findings on the basic mechanisms underlying hyperalgesia during DOMS, which is a useful model to study myofascial pain syndrome, and the role of NGF on muscular nociception. This might be useful in the search for new pharmacologic targets and therapeutic approaches. Copyright © 2013 American Pain Society. Published by Elsevier Inc. All rights reserved.

The effect of hyperthyroidism on opiate receptor binding and pain sensitivity

International Nuclear Information System (INIS)

Edmondson, E.A.; Bonnet, K.A.; Friedhoff, A.J.

1990-01-01

This study was conducted to determine the effect of thyroid hormone on opiate receptor ligand-binding and pain sensitivity. Specific opiate receptor-binding was performed on brain homogenates of Swiss-Webster mice. There was a significant increase in 3 H-naloxone-binding in thyroxine-fed subjects (hyperthyroid). Scatchard analysis revealed that the number of opiate receptors was increased in hyperthyroid mice (Bmax = 0.238 nM for hyperthyroid samples vs. 0.174 nM for controls). Binding affinity was unaffected (Kd = 1.54 nM for hyperthyroid and 1.58 nM for control samples). When mice were subjected to hotplate stimulation, the hyperthyroid mice were noted to be more sensitive as judged by pain aversion response latencies which were half that of control animals. After morphine administration, the hyperthyroid animals demonstrated a shorter duration of analgesia. These findings demonstrate that thyroxine increases opiate receptor number and native pain sensitivity but decreases the duration of analgesia from morphine

The effect of hyperthyroidism on opiate receptor binding and pain sensitivity

Energy Technology Data Exchange (ETDEWEB)

Edmondson, E.A. (Baylor College of Medicine, Houston, TX (USA)); Bonnet, K.A.; Friedhoff, A.J. (New York Univ. School of Medicine, NY (USA))

1990-01-01

This study was conducted to determine the effect of thyroid hormone on opiate receptor ligand-binding and pain sensitivity. Specific opiate receptor-binding was performed on brain homogenates of Swiss-Webster mice. There was a significant increase in {sup 3}H-naloxone-binding in thyroxine-fed subjects (hyperthyroid). Scatchard analysis revealed that the number of opiate receptors was increased in hyperthyroid mice (Bmax = 0.238 nM for hyperthyroid samples vs. 0.174 nM for controls). Binding affinity was unaffected (Kd = 1.54 nM for hyperthyroid and 1.58 nM for control samples). When mice were subjected to hotplate stimulation, the hyperthyroid mice were noted to be more sensitive as judged by pain aversion response latencies which were half that of control animals. After morphine administration, the hyperthyroid animals demonstrated a shorter duration of analgesia. These findings demonstrate that thyroxine increases opiate receptor number and native pain sensitivity but decreases the duration of analgesia from morphine.

Exercise increases pressure pain tolerance but not pressure and heat pain thresholds in healthy young men.

Science.gov (United States)

Vaegter, H B; Hoeger Bement, M; Madsen, A B; Fridriksson, J; Dasa, M; Graven-Nielsen, T

2017-01-01

Exercise causes an acute decrease in the pain sensitivity known as exercise-induced hypoalgesia (EIH), but the specificity to certain pain modalities remains unknown. This study aimed to compare the effect of isometric exercise on the heat and pressure pain sensitivity. On three different days, 20 healthy young men performed two submaximal isometric knee extensions (30% maximal voluntary contraction in 3 min) and a control condition (quiet rest). Before and immediately after exercise and rest, the sensitivity to heat pain and pressure pain was assessed in randomized and counterbalanced order. Cuff pressure pain threshold (cPPT) and pain tolerance (cPTT) were assessed on the ipsilateral lower leg by computer-controlled cuff algometry. Heat pain threshold (HPT) was recorded on the ipsilateral foot by a computer-controlled thermal stimulator. Cuff pressure pain tolerance was significantly increased after exercise compared with baseline and rest (p  0.77) compared with HPT (intraclass correlation = 0.54). The results indicate that hypoalgesia after submaximal isometric exercise is primarily affecting tolerance of pressure pain compared with the pain threshold. These data contribute to the understanding of how isometric exercise influences pain perception, which is necessary to optimize the clinical utility of exercise in management of chronic pain. The effect of isometric exercise on pain tolerance may be relevant for patients in chronic musculoskeletal pain as a pain-coping strategy. WHAT DOES THIS STUDY ADD?: The results indicate that hypoalgesia after submaximal isometric exercise is primarily affecting tolerance of pressure pain compared with the heat and pressure pain threshold. These data contribute to the understanding of how isometric exercise influences pain perception, which is necessary to optimize the clinical utility of exercise in management of chronic pain. © 2016 European Pain Federation - EFIC®.

Bilateral experimental neck pain reorganize axioscapular muscle coordination and pain sensitivity.

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Christensen, S W; Hirata, R P; Graven-Nielsen, T

2017-04-01

Neck pain is a large clinical problem where reorganized trunk and axioscapular muscle activities have been hypothesised contributing to pain persistence and pain hypersensitivity. This study investigated the effects of bilateral experimental neck pain on trunk and axioscapular muscle function and pain sensitivity. In 25 healthy volunteers, bilateral experimental neck pain was induced in the splenius capitis muscles by hypertonic saline injections. Isotonic saline was used as control. In sitting, subjects performed slow, fast and slow-resisted unilateral arm movements before, during and after injections. Electromyography (EMG) was recorded from eight shoulder and trunk muscles bilaterally. Pressure pain thresholds (PPTs) were assessed bilaterally at the neck, head and arm. Data were normalized to the before-measures. Compared with control and post measurements, experimental neck pain caused (1) decreased EMG activity of the ipsilateral upper trapezius muscles during all but slow-resisted down movements (p neck pain reorganized axioscapular and trunk muscle activity together with local hyperalgesia and widespread hypoalgesia indicating that acute neck pain immediately affects trunk and axioscapular function which may affect both assessment and treatment. Bilateral clinical neck pain alters axioscapular muscle coordination but only effects of unilateral experimental neck pain has been investigated. Bilateral experimental neck pain causes task-dependent reorganized axioscapular and trunk muscle activity in addition to widespread decrease in pressure pain sensitivity. © 2016 European Pain Federation - EFIC®.

Preoperative widespread pain sensitization and chronic pain after hip and knee replacement: a cohort analysis

Science.gov (United States)

Wylde, Vikki; Sayers, Adrian; Lenguerrand, Erik; Gooberman-Hill, Rachael; Pyke, Mark; Beswick, Andrew D.; Dieppe, Paul; Blom, Ashley W.

2015-01-01

Abstract Chronic pain after joint replacement is common, affecting approximately 10% of patients after total hip replacement (THR) and 20% of patients after total knee replacement (TKR). Heightened generalized sensitivity to nociceptive input could be a risk factor for the development of this pain. The primary aim of this study was to investigate whether preoperative widespread pain sensitivity was associated with chronic pain after joint replacement. Data were analyzed from 254 patients receiving THR and 239 patients receiving TKR. Pain was assessed preoperatively and at 12 months after surgery using the Western Ontario and McMaster Universities Osteoarthritis Pain Scale. Preoperative widespread pain sensitivity was assessed through measurement of pressure pain thresholds (PPTs) at the forearm using an algometer. Statistical analysis was conducted using linear regression and linear mixed models, and adjustments were made for confounding variables. In both the THR and TKR cohort, lower PPTs (heightened widespread pain sensitivity) were significantly associated with higher preoperative pain severity. Lower PPTs were also significantly associated with higher pain severity at 12 months after surgery in the THR cohort. However, PPTs were not associated with the change in pain severity from preoperative to 12 months postoperative in either the TKR or THR cohort. These findings suggest that although preoperative widespread pressure pain sensitivity is associated with pain severity before and after joint replacement, it is not a predictor of the amount of pain relief that patients gain from joint replacement surgery, independent of preoperative pain severity. PMID:25599300

Pleasure and pain: the effect of (almost) having an orgasm on genital and nongenital sensitivity.

Science.gov (United States)

Paterson, Laurel Q P; Amsel, Rhonda; Binik, Yitzchak M

2013-06-01

The effect of sexual arousal and orgasm on genital sensitivity has received little research attention, and no study has assessed sensation pleasurableness as well as painfulness. To clarify the relationship between sexual arousal, orgasm, and sensitivity in a healthy female sample. Twenty-six women privately masturbated to orgasm and almost to orgasm at two separate sessions, during which standardized pressure stimulation was applied to the glans clitoris, vulvar vestibule, and volar forearm at three testing times: (i) baseline; (ii) immediately following masturbation; and (iii) following a subsequent 15-minute rest period. Touch thresholds (tactile detection sensitivity), sensation pleasurableness ratings (pleasurable sensitivity), and pain thresholds (pain sensitivity). Pleasurableness ratings were higher on the glans clitoris than the vulvar vestibule, and at most testing times on the vulvar vestibule than the volar forearm; and at baseline and immediately after masturbation than 15 minutes later, mainly on the genital locations only. Pain thresholds were lower on the genital locations than the volar forearm, and immediately and 15 minutes after masturbation than at baseline. After orgasm, genital pleasurableness ratings and vulvar vestibular pain thresholds were lower than after masturbation almost to orgasm. Post-masturbation pleasurableness ratings were positively correlated with pain thresholds but only on the glans clitoris. Hormonal contraception users had lower pleasurableness ratings and pain thresholds on all locations than nonusers. There were no significant effects for touch thresholds. Masturbation appears to maintain pleasurable genital sensitivity but increase pain sensitivity, with lower genital pleasurable sensitivity and higher vulvar vestibular pain sensitivity when orgasm occurs. Findings suggest that enhancing stimulation pleasurableness, psychological sexual arousal and lubrication mitigate normative increases in pain sensitivity during

Entropy of Masseter Muscle Pain Sensitivity: A New Technique for Pain Assessment.

Science.gov (United States)

Castrillon, Eduardo E; Exposto, Fernando G; Sato, Hitoshi; Tanosoto, Tomohiro; Arima, Taro; Baad-Hansen, Lene; Svensson, Peter

2017-01-01

To test whether manipulation of mechanical pain sensitivity (MPS) of the masseter muscle is reflected in quantitative measures of entropy. In a randomized, single-blinded, placebo-controlled design, 20 healthy volunteers had glutamate, lidocaine, and isotonic saline injected into the masseter muscle. Self-assessed pain intensity on a numeric rating scale (NRS) was evaluated up to 10 minutes following the injection, and MPS was evaluated after application (at 5 minutes and 30 minutes) of three different forces (0.5 kg, 1 kg, and 2 kg) to 15 different sites of the masseter muscle. Finally, the entropy and center of gravity (COG) of the pain sensitivity scores were calculated. Analysis of variance was used to test differences in means of tested outcomes and Tukey post hoc tests were used to adjust for multiple comparisons. The main findings were: (1) Compared with both lidocaine and isotonic saline, glutamate injections caused an increase in peak, duration, and area under the NRS pain curve (P entropy values (P entropy values when assessed with 0.5 kg and 1.0 kg but not with 2.0 kg of pressure; and (4) COG coordinates revealed differences between the x coordinates for time (P entropy measures. Entropy allows quantification of the diversity of MPS, which may be important in clinical assessment of pain states such as myofascial temporomandibular disorders.

Generalized mechanical pain sensitivity over nerve tissues in patients with strictly unilateral migraine.

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Fernández-de-las-Peñas, César; Arendt-Nielsen, Lars; Cuadrado, María Luz; Pareja, Juan A

2009-06-01

No study has previously analyzed pressure pain sensitivity of nerve trunks in migraine. This study aimed to examine the differences in mechanical pain sensitivity over specific nerves between patients with unilateral migraine and healthy controls. Blinded investigators assessed pressure pain thresholds (PPT) over the supra-orbital nerves (V1) and peripheral nerve trunks of both upper extremities (median, radial, and ulnar nerves) in 20 patients with strictly unilateral migraine and 20 healthy matched controls. Pain intensity after palpation over both supra-orbital nerves was also assessed. A pressure algometer was used to quantify PPT, whereas a 10-point numerical pain rate scale was used to evaluate pain to palpation over the supra-orbital nerve. The analysis of covariance revealed that pain to palpation over the supra-orbital nerve was significantly higher (P0.6). In patients with unilateral migraine, we found increased mechano-sensitivity of the supra-orbital nerve on the symptomatic side of the head. Outside the head, the same patients showed increased mechano-sensitivity of the main peripheral nerves of both upper limbs, without asymmetries. Such diffuse hypersensitivity of the peripheral nerves lends further evidence to the presence of a state of hyperexcitability of the central nervous system in patients with unilateral migraine.

Increased pain sensitivity in accident-related chronic pain patients with comorbid posttraumatic stress

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Vaegter, Henrik Bjarke; Andersen, Tonny Elmose; Harvold, Mathea

2018-01-01

, anxiety, pain catastrophizing, and fear of movement) in patients with accident-related chronic spinal pain with (N=44) and without (N=64) comorbid PTSD characteristics. METHODS: Cuff algometry was performed on lower legs to assess pressure pain threshold (cPPT), tolerance (cPTT), temporal summation...

Association Between Genetic Polymorphisms and Pain Sensitivity in Patients with Hip Osteoarthritis

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Olesen, Anne E; Nielsen, Lecia M; Feddersen, Søren

2018-01-01

, kappa, and delta opioid receptor genes (OPRM1, OPRK1, and OPRD1) and the catechol-O-methyltransferase gene (COMT) influenced the pain phenotype in patients with osteoarthritis. METHODS: The frequencies of 17 polymorphisms were examined. Pain sensitivity was assessed preoperatively by (1) hip rotation......BACKGROUND: Factors such as age, gender, and genetic polymorphisms may explain individual differences in pain phenotype. Genetic associations with pain sensitivity have previously been investigated in osteoarthritis patients, with a focus on the P2X7, TRPV1, and TACR1 genes. However, other genes...... may play a role as well. Osteoarthritis is a common joint disease, and many patients suffering from this disease are thought to have increased sensitivity to noxious stimuli resulting from sensitization in the nociceptive system. The aim of this study was to investigate if genetic variants of mu...

Mucosal versus muscle pain sensitivity in provoked vestibulodynia

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Witzeman K

2015-08-01

Full Text Available Kathryn Witzeman,1 Ruby HN Nguyen,2 Alisa Eanes,3 Sawsan As-Sanie,4 Denniz Zolnoun51Department of Obstetrics and Gynecology, Denver Health Medical Center, Denver, CO, 2Division of Epidemiology and Community Health, University of Minnesota, Minneapolis, MN, 3Pelvic Pain Research Unit, Division of Advanced Laparoscopy and Pelvic Pain, Department of Obstetrics and Gynecology, University of North Carolina School of Medicine, Chapel Hill, NC, 4Department of Obstetrics and Gynecology, Division of Minimally Invasive Gynecologic Surgery, University of Michigan, Ann Arbor, MI, 5Department of Obstetrics and Gynecology and Center for Neurosensory Disorders, University of North Carolina, Chapel Hill, NC, USABackground: An estimated 8.3%–16% of women experience vulvovaginal discomfort during their lifetime. Frequently these patients report provoked pain on contact or with attempted intercourse, commonly referred to as provoked vestibulodynia (PVD. Despite the burden of this condition, little is known about its potential etiologies including pelvic floor muscular dysfunction and mucosal components. This knowledge would be beneficial in developing targeted therapies including physical therapy.Objective: To explore the relative contribution of mucosal versus muscle pain sensitivity on pain report from intercourse among women with PVD.Design: In this proof of concept study, 54 women with PVD underwent a structured examination assessing mucosal and pelvic muscle sensitivity.Methods: We examined three mucosal sites in the upper and lower vestibule. Patients were asked to rate their pain on cotton swab palpation of the mucosa using a 10-point visual analog scale. Muscle pain was assessed using transvaginal application of pressure on right and left puborectalis, and the perineal muscle complex. The Gracely pain scale (0–100 was used to assess the severity of pain with intercourse, with women rating the lowest, average, and highest pain levels; a 100 rating the

Pain thresholds, supra-threshold pain and lidocaine sensitivity in patients with erythromelalgia, including the I848Tmutation in NaV 1.7.

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Helås, T; Sagafos, D; Kleggetveit, I P; Quiding, H; Jönsson, B; Segerdahl, M; Zhang, Z; Salter, H; Schmelz, M; Jørum, E

2017-09-01

Nociceptive thresholds and supra-threshold pain ratings as well as their reduction upon local injection with lidocaine were compared between healthy subjects and patients with erythromelalgia (EM). Lidocaine (0.25, 0.50, 1.0 or 10 mg/mL) or placebo (saline) was injected intradermally in non-painful areas of the lower arm, in a randomized, double-blind manner, to test the effect on dynamic and static mechanical sensitivity, mechanical pain sensitivity, thermal thresholds and supra-threshold heat pain sensitivity. Heat pain thresholds and pain ratings to supra-threshold heat stimulation did not differ between EM-patients (n = 27) and controls (n = 25), neither did the dose-response curves for lidocaine. Only the subgroup of EM-patients with mutations in sodium channel subunits Na V 1.7, 1.8 or 1.9 (n = 8) had increased lidocaine sensitivity for supra-threshold heat stimuli, contrasting lower sensitivity to strong mechanical stimuli. This pattern was particularly clear in the two patients carrying the Na V 1.7 I848T mutations in whom lidocaine's hyperalgesic effect on mechanical pain sensitivity contrasted more effective heat analgesia. Heat pain thresholds are not sensitized in EM patients, even in those with gain-of-function mutations in Na V 1.7. Differential lidocaine sensitivity was overt only for noxious stimuli in the supra-threshold range suggesting that sensitized supra-threshold encoding is important for the clinical pain phenotype in EM in addition to lower activation threshold. Intracutaneous lidocaine dose-dependently blocked nociceptive sensations, but we did not identify EM patients with particular high lidocaine sensitivity that could have provided valuable therapeutic guidance. Acute pain thresholds and supra-threshold heat pain in controls and patients with erythromelalgia do not differ and have the same lidocaine sensitivity. Acute heat pain thresholds even in EM patients with the Na V 1.7 I848T mutation are normal and only nociceptor

The effects of total knee replacement and non-surgical treatment on pain sensitization and clinical pain

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Skou, S. T.; Roos, E. M.; Simonsen, O.

2016-01-01

(PPTs) at the knee (localized sensitization) and the lower leg (spreading sensitization), (2) peak pain intensity during the previous 24 h, (3) pain intensity after 30 min of walking, (4) pain location and pattern, (5) spreading of pain on a region-divided body chart and (6) the usage of pain medication...

Endogenous Opioid-Masked Latent Pain Sensitization

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Pereira, Manuel P; Donahue, Renee R; Dahl, Jørgen B

2015-01-01

UNLABELLED: Following the resolution of a severe inflammatory injury in rodents, administration of mu-opioid receptor inverse agonists leads to reinstatement of pain hypersensitivity. The mechanisms underlying this form of latent pain sensitization (LS) likely contribute to the development of chr...

Blood pressure and pain sensitivity in children and adolescents.

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Drouin, Sammantha; McGrath, Jennifer J

2013-06-01

Elevated blood pressure is associated with diminished pain sensitivity. While this finding is well established in adults, it is less clear when the relation between blood pressure and pain sensitivity emerges across the life course. Evidence suggests this phenomenon may exist during childhood. Children (N = 309; 56% boys) aged 10-15 years and their parents participated. Blood pressure readings were taken during a resting baseline. Maximum pain intensity was rated using a visual analogue scale (rated 0-10) in response to a finger prick pain induction. Parent-measured resting blood pressure was inversely associated with boys' pain ratings only. Cross-sectionally, lower pain ratings were related to higher SBP, univariately. Longitudinally, pain ratings predicted higher DBP, even after controlling for covariates. Determining when and how the relation between blood pressure and pain sensitivity emerges may elucidate the pathophysiology of hypertension. Copyright © 2013 Society for Psychophysiological Research.

Pain perception is increased in congenital but not late onset blindness

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Slimani, Hocine; Danti, Sabrina; Ptito, Maurice

2014-01-01

There is now ample evidence that blind individuals outperform sighted individuals in various tasks involving the non-visual senses. In line with these results, we recently showed that visual deprivation from birth leads to an increased sensitivity to pain. As many studies have shown that congenit......There is now ample evidence that blind individuals outperform sighted individuals in various tasks involving the non-visual senses. In line with these results, we recently showed that visual deprivation from birth leads to an increased sensitivity to pain. As many studies have shown...... that congenitally and late blind individuals show differences in their degree of compensatory plasticity, we here address the question whether late blind individuals also show hypersensitivity to nociceptive stimulation. We therefore compared pain thresholds and responses to supra-threshold nociceptive stimuli...... in congenitally blind, late blind and normally sighted volunteers. Participants also filled in questionnaires measuring attention and anxiety towards pain in everyday life. Results show that late blind participants have pain thresholds and ratings of supra-threshold heat nociceptive stimuli similar...

Gender expression, sexual orientation and pain sensitivity in women.

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Vigil, Jacob M; Rowell, Lauren N; Lutz, Charlotte

2014-01-01

Despite a growing body of literature investigating sex differences with regard to pain, surprisingly little research has been conducted on the influence of various aspects of self-identity, including gender expression and sexual orientation, on pain sensitivity within each sex, particularly among women. In men, dispositional femininity is linked to greater clinical pain and trait masculinity is associated with higher pain thresholds. To examine whether gender expression and sexual orientation are associated with within-sex differences in ischemic pain sensitivity in healthy young women. A convenience sample of 172 females (mean age 21.4 years; range 18 to 30 years of age; 56.0% white, 89% heterosexual) performed an ischemic pain task in counterbalanced order. Desired levels of dispositional femininity for a preferred romantic partner and self-described levels of personal dispositional femininity were measured. Compared with heterosexual women, lesbian and bisexual women reported lower pain intensity ratings early in the discomfort task. Irrespective of sexual orientation, attraction to more feminine romantic partners and dispositional masculinity were correlated with lower pain intensity, and with higher pain thresholds and tolerance levels. These preliminary findings suggest that within-sex differences in sexual orientation and other aspects of identity, irrespective of biological sex, may be important to consider when examining experimental pain performance and clinical pain experiences. Larger investigations of the psychophysiological relationships among sexual orientation, gender expression and pain sensitivity are warranted. These findings may have implications for differences in clinical pain sensitivity of lesbian and bisexual women compared with heterosexual women.

Assessment of musculoskeletal pain sensitivity and temporal summation by cuff pressure algometry

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Graven-Nielsen, Thomas; Vaegter, Henrik Bjarke; Finocchietti, Sara

2015-01-01

) conditioned pain modulation (CPM) assessed by cuff algometry. The influences of age and gender were evaluated. On two different days, cuff pain threshold (cPPT), cuff pain tolerance (cPTT), and temporal summation of pain (TSP) by visual analogue scale scores to 10 repeated cuff stimulations at cPTT intensity......, as well as pressure pain threshold (PPT) with handheld pressure algometry were assessed in 136 healthy subjects. In one session cuff pain sensitivity was also assessed before and after the cold-pressor induced CPM. Good to excellent intraclass correlations (ICCs: 0.60 - 0.90) were demonstrated for manual.......05). TSP were increased in women compared with men (PCPM demonstrated as increased cPPT, cPTT and reduced TSP (P

Modification of COMT-dependent pain sensitivity by psychological stress and sex.

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Meloto, Carolina B; Bortsov, Andrey V; Bair, Eric; Helgeson, Erika; Ostrom, Cara; Smith, Shad B; Dubner, Ronald; Slade, Gary D; Fillingim, Roger B; Greenspan, Joel D; Ohrbach, Richard; Maixner, William; McLean, Samuel A; Diatchenko, Luda

2016-04-01

Catecholamine-O-methyltransferase (COMT) is a polymorphic gene whose variants affect enzymatic activity and pain sensitivity via adrenergic pathways. Although COMT represents one of the most studied genes in human pain genetics, findings regarding its association with pain phenotypes are not always replicated. Here, we investigated if interactions among functional COMT haplotypes, stress, and sex can modify the effect of COMT genetic variants on pain sensitivity. We tested these interactions in a cross-sectional study, including 2 cohorts, one of 2972 subjects tested for thermal pain sensitivity (Orofacial Pain: Prospective Evaluation and Risk Assessment) and one of 948 subjects with clinical acute pain after motor vehicle collision (post-motor vehicle collision). In both cohorts, the COMT high-pain sensitivity (HPS) haplotype showed robust interaction with stress and number of copies of the HPS haplotype was positively associated with pain sensitivity in nonstressed individuals, but not in stressed individuals. In the post-motor vehicle collision cohort, there was additional modification by sex: the HPS-stress interaction was apparent in males, but not in females. In summary, our findings indicate that stress and sex should be evaluated in association studies aiming to investigate the effect of COMT genetic variants on pain sensitivity.

Kinesiophobia is associated with pain intensity but not pain sensitivity before and after exercise

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Vægter, Henrik Bjarke; Madsen, Anders Bjarke; Handberg, Gitte

2018-01-01

OBJECTIVE: To compare clinical pain intensity, exercise performance, pain sensitivity and the effect of aerobic and isometric exercise on local and remote pressure pain thresholds (PPTs) in patients with chronic musculoskeletal pain with high and low levels of kinesiophobia. DESIGN: An experiment...

Reduction of pain sensitivity after somatosensory therapy in adults with cerebral palsy

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Inmaculada eRiquelme

2013-06-01

Full Text Available Objective. Pain and deficits in somatosensory processing seem to play a relevant role in cerebral palsy (CP. Rehabilitation techniques based on neuroplasticity mechanisms may induce powerful changes in the organization of the primary somatosensory cortex and have been proved to reduce levels of pain and discomfort in neurological pathologies. However, little is known about the efficacy of such interventions for pain sensitivity in CP individuals. Methods. Adults with cerebral palsy participated in the study and were randomly assigned to the intervention (n=17 or the control group (n=20. The intervention group received a somatosensory therapy including 4 types of exercises (touch, proprioception, vibration, and stereognosis. All participants were asked to continue their standardized motor therapy during the study period. Several somatosensory (pain and touch thresholds, stereognosis, propioception, texture recognition and motor parameters (fine motor skills were assessed before, immediately after and three months after the therapy (follow-up. Results. Participants of the intervention group showed a significant reduction on pain sensitivity after treatment and at follow-up after three months, whereas participants in the control group displayed increasing pain sensitivity over time. No improvements were found on touch sensitivity, proprioception, texture recognition or fine motor skills. Conclusions. Data suggest the possibility that somatosensory therapy was effective in eliciting changes in central somatosensory processing. This hypothesis may have implications for future neuromodulatory treatment of pain complaints in children and adults with cerebral palsy.

Pain as social glue: shared pain increases cooperation.

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Bastian, Brock; Jetten, Jolanda; Ferris, Laura J

2014-11-01

Even though painful experiences are employed within social rituals across the world, little is known about the social effects of pain. We examined the possibility that painful experiences can promote cooperation within social groups. In Experiments 1 and 2, we induced pain by asking some participants to insert their hands in ice water and to perform leg squats. In Experiment 3, we induced pain by asking some participants to eat a hot chili pepper. Participants performed these tasks in small groups. We found evidence for a causal link: Sharing painful experiences with other people, compared with a no-pain control treatment, promoted trusting interpersonal relationships by increasing perceived bonding among strangers (Experiment 1) and increased cooperation in an economic game (Experiments 2 and 3). Our findings shed light on the social effects of pain, demonstrating that shared pain may be an important trigger for group formation. © The Author(s) 2014.

Somatosensory sensitivity in patients with persistent idiopathic orofacial pain is associated with pain relief from hypnosis and relaxation.

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Baad-Hansen, Lene; Abrahamsen, Randi; Zachariae, Robert; List, Thomas; Svensson, Peter

2013-06-01

In a recent study hypnosis has been found to relieve persistent idiopathic orofacial pain. Quantitative sensory testing (QST) is widely used to evaluate somatosensory sensitivity, which has been suggested as a possible predictor of management outcome. The objectives of this study were to examine: (1) possible associations between clinical pain relief and baseline somatosensory sensitivity and (2) the effect of hypnosis management on QST parameters. Forty-one patients with persistent idiopathic orofacial pain completed this randomized controlled study in 1 of 2 groups: hypnosis (hypnotic analgesia suggestions) or control (relaxation). QST at 2 intraoral (pain region and contralateral mirror image region) and 3 extraoral (hand and both cheeks) sites was performed at baseline and after the hypnosis/control management, together with pressure pain thresholds and pressure pain tolerance thresholds determined bilaterally at the masseter and temporalis muscles, the temporomandibular joints, and the third finger. Degree of pain relief was negatively correlated with a summary statistic of baseline somatosensory sensitivity (summed z-score), that is, high baseline somatosensory sensitivity was associated with low pain relief (r=-0.372, P=0.020). Hypnosis had no major effect on any QST measure compared with relaxation (P>0.063). High pain sensitivity at baseline may predict poor pain management outcome. In addition, despite clear clinical pain relief, hypnosis did not significantly or specifically influence somatosensory sensitivity. Future studies should further explore QST measures as possible predictors of different management response in orofacial pain conditions.

Combined glutamate and glutamine levels in pain-processing brain regions are associated with individual pain sensitivity.

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Zunhammer, Matthias; Schweizer, Lauren M; Witte, Vanessa; Harris, Richard E; Bingel, Ulrike; Schmidt-Wilcke, Tobias

2016-10-01

The relationship between glutamate and γ-aminobutyric acid (GABA) levels in the living human brain and pain sensitivity is unknown. Combined glutamine/glutamate (Glx), as well as GABA levels can be measured in vivo with single-voxel proton magnetic resonance spectroscopy. In this cross-sectional study, we aimed at determining whether Glx and/or GABA levels in pain-related brain regions are associated with individual differences in pain sensitivity. Experimental heat, cold, and mechanical pain thresholds were obtained from 39 healthy, drug-free individuals (25 men) according to the quantitative sensory testing protocol and summarized into 1 composite measure of pain sensitivity. The Glx levels were measured using point-resolved spectroscopy at 3 T, within a network of pain-associated brain regions comprising the insula, the anterior cingulate cortex, the mid-cingulate cortex, the dorsolateral prefrontal cortex, and the thalamus. GABA levels were measured using GABA-edited spectroscopy (Mescher-Garwood point-resolved spectroscopy) within the insula, the anterior cingulate cortex, and the mid-cingulate cortex. Glx and/or GABA levels correlated positively across all brain regions. Gender, weekly alcohol consumption, and depressive symptoms were significantly associated with Glx and/or GABA levels. A linear regression analysis including all these factors indicated that Glx levels pooled across pain-related brain regions were positively associated with pain sensitivity, whereas no appreciable relationship with GABA was found. In sum, we show that the levels of the excitatory neurotransmitter glutamate and its precursor glutamine across pain-related brain regions are positively correlated with individual pain sensitivity. Future studies will have to determine whether our findings also apply to clinical populations.

GCH1-polymorphism and pain sensitivity among women with provoked vestibulodynia

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Heddini Ulrika

2012-09-01

Full Text Available Abstract Background Provoked vestibulodynia (PVD is a pain disorder localized in the vestibular mucosa. It is the most common cause of dyspareunia among young women and it is associated with general pain hypersensitivity and other chronic pain conditions. Polymorphism in the guanosine triphosphate cyclohydrolase (GCH1 gene has been found to influence general pain sensitivity and the risk of developing a longstanding pain condition. The aim of this study was to investigate GCH1-polymorphism in women with PVD and healthy controls, in correlation to pain sensitivity. Results We found no correlation between the previously defined pain-protective GCH1-SNP combination and the diagnosis of PVD. Nor any correlation with pain sensitivity measured as pressure pain thresholds on the arm, leg and in the vestibule, coital pain scored on a visual analog scale and prevalence of other bodily pain conditions among women with PVD (n = 98 and healthy controls (n = 102. However, among patients with current treatment (n = 36, there was a significant interaction effect of GCH1-gene polymorphism and hormonal contraceptive (HC therapy on coital pain (p = 0.04 as well as on pressure pain thresholds on the arm (p = 0.04. PVD patients carrying the specified SNP combination and using HCs had higher pain sensitivity compared to non-carriers. In non-HC-users, carriers had lower pain sensitivity. Conclusions The results of this study gave no support to the hypothesis that polymorphism in the GCH1-gene contributes to the etiology of PVD. However, among patients currently receiving treatment an interaction effect of the defined SNP combination and use of hormonal contraceptives on pain sensitivity was found. This finding offers a possible explanation to the clinically known fact that some PVD patients improve after cessation of hormonal contraceptives, indicating that PVD patients carrying the defined SNP combination of GCH1 would benefit from this

Assay sensitivity of pain intensity versus pain relief in acute pain clinical trials: ACTTION systematic review and meta-analysis.

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Singla, Neil; Hunsinger, Matthew; Chang, Phoebe D; McDermott, Michael P; Chowdhry, Amit K; Desjardins, Paul J; Turk, Dennis C; Dworkin, Robert H

2015-08-01

The magnitude of the effect size of an analgesic intervention can be influenced by several factors, including research design. A key design component is the choice of the primary endpoint. The purpose of this meta-analysis was to compare the assay sensitivity of 2 efficacy paradigms: pain intensity (calculated using summed pain intensity difference [SPID]) and pain relief (calculated using total pain relief [TOTPAR]). A systematic review of the literature was performed to identify acute pain studies that calculated both SPIDs and TOTPARs within the same study. Studies were included in this review if they were randomized, double-blind, placebo-controlled investigations involving medications for postsurgical acute pain and if enough data were provided to calculate TOTPAR and SPID standardized effect sizes. Based on a meta-analysis of 45 studies, the mean standardized effect size for TOTPAR (1.13) was .11 higher than that for SPID (1.02; P = .01). Mixed-effects meta-regression analyses found no significant associations between the TOTPAR - SPID difference in standardized effect size and trial design characteristics. Results from this review suggest that for acute pain studies, utilizing TOTPAR to assess pain relief may be more sensitive to treatment effects than utilizing SPID to assess pain intensity. The results of this meta-analysis suggest that TOTPAR may be more sensitive to treatment effects than SPIDs are in analgesic trials examining acute pain. We found that standardized effect sizes were higher for TOTPAR compared to SPIDs. Copyright © 2015 American Pain Society. Published by Elsevier Inc. All rights reserved.

Central sensitization in chronic low back pain: A narrative review.

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Sanzarello, Ilaria; Merlini, Luciano; Rosa, Michele Attilio; Perrone, Mariada; Frugiuele, Jacopo; Borghi, Raffaele; Faldini, Cesare

2016-11-21

Low back pain is one of the four most common disorders in all regions, and the greatest contributor to disability worldwide, adding 10.7% of total years lost due to this health state. The etiology of chronic low back pain is, in most of the cases (up to 85%), unknown or nonspecific, while the specific causes (specific spinal pathology and neuropathic/radicular disorders) are uncommon. Central sensitization has been recently recognized as a potential pathophysiological mechanism underlying a group of chronic pain conditions, and may be a contributory factor for a sub-group of patients with chronic low back pain. The purposes of this narrative review are twofold. First, to describe central sensitization and its symptoms and signs in patients with chronic pain disorders in order to allow its recognition in patients with nonspecific low back pain. Second, to provide general treatment principles of chronic low back pain with particular emphasis on pharmacotherapy targeting central sensitization.

Exercise increases pressure pain tolerance but not pressure and heat pain thresholds in healthy young men

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Vaegter, H. B.; Bement, M. Hoeger; Madsen, A. B.

2017-01-01

BACKGROUND: Exercise causes an acute decrease in the pain sensitivity known as exercise-induced hypoalgesia (EIH), but the specificity to certain pain modalities remains unknown. This study aimed to compare the effect of isometric exercise on the heat and pressure pain sensitivity. METHODS...... and counterbalanced order. Cuff pressure pain threshold (cPPT) and pain tolerance (cPTT) were assessed on the ipsilateral lower leg by computer-controlled cuff algometry. Heat pain threshold (HPT) was recorded on the ipsilateral foot by a computer-controlled thermal stimulator. RESULTS: Cuff pressure pain tolerance...... to the understanding of how isometric exercise influences pain perception, which is necessary to optimize the clinical utility of exercise in management of chronic pain. SIGNIFICANCE: The effect of isometric exercise on pain tolerance may be relevant for patients in chronic musculoskeletal pain as a pain...

Spotlight on topographical pressure pain sensitivity maps: a review

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Alburquerque-Sendín F

2018-01-01

Full Text Available Francisco Alburquerque-Sendín,1 Pascal Madeleine,2 César Fernández-de-las-Peñas,3 Paula Rezende Camargo,4 Tania Fátima Salvini4 1Department of Socio-Sanitary Sciences, Radiology and Physical Medicine, Universidad de Córdoba, Córdoba, Spain; 2Physical Activity and Human Performance Group, SMI, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark; 3Department of Physical Therapy, Occupational Therapy, Physical Medicine and Rehabilitation, Universidad Rey Juan Carlos, Madrid, Spain; 4Department of Physical Therapy, Federal University of São Carlos, São Carlos, SP, Brazil Abstract: Mechanical hyperalgesia defined as decreased pressure pain thresholds (PPTs is commonly associated with pain. In this narrative review, we report the current state of the art within topographical pressure sensitivity maps. Such maps are based on multiple PPT assessments. The PPTs are assessed by an a priori defined grid with special focus on both spatial and temporal summation issues. The grid covers the muscle or the body region of interest using absolute or relative values determined from anatomical landmarks or anthropometric values. The collected PPTs are interpolated by Shepard or Franke and Nielson interpolation methods to create topographical pressure sensitivity maps. This new imaging technique has proven to be valuable in various disciplines including exercise physiology, neurology, physical therapy, occupational medicine, oncology, orthopedics, and sport sciences. The reviewed papers have targeted different body regions like the scalp, low back, neck–shoulder, and upper and lower extremities. The maps have delineated spatial heterogeneity in the pressure pain sensitivity underlining the different extents of pressure pain hyperalgesia in both experimentally induced and disease-associated pain conditions. Furthermore, various intervention studies have proven the utility of topographical pressure pain

Treatment of central sensitization in patients with 'unexplained' chronic pain: what options do we have?

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Nijs, Jo; Meeus, Mira; Van Oosterwijck, Jessica; Roussel, Nathalie; De Kooning, Margot; Ickmans, Kelly; Matic, Milica

2011-05-01

Central sensitization accounts for chronic 'unexplained' pain in a wide variety of disorders, including chronic whiplash-associated disorders, temporomandibular disorders, chronic low back pain, osteoarthritis, fibromyalgia, chronic fatigue syndrome and chronic tension-type headache among others. Given the increasing evidence supporting the clinical significance of central sensitization in those with unexplained chronic pain, the awareness is growing that central sensitization should be a treatment target in these patients. This article provides an overview of the treatment options available for desensitizing the CNS in patients with chronic pain due to central sensitization. It focuses on those strategies that specifically target pathophysiological mechanisms known to be involved in central sensitization. In addition, pharmacological options, rehabilitation and neurotechnology options are discussed. Acetaminophen, serotonin-reuptake inhibitor drugs, selective and balanced serototin and norepinephrine-reuptake inhibitor drugs, the serotonin precursor tryptophan, opioids, N-methyl-d-aspartate (NMDA)-receptor antagonists, calcium-channel alpha(2)delta (a2δ) ligands, transcranial magnetic stimulation, transcutaneous electric nerve stimulation (TENS), manual therapy and stress management each target central pain processing mechanisms in animals that - theoretically - desensitize the CNS in humans. To provide a comprehensive treatment for 'unexplained' chronic pain disorders characterized by central sensitization, it is advocated to combine the best evidence available with treatment modalities known to target central sensitization. © 2011 Informa UK, Ltd

Spinal Manipulative Therapy Specific Changes In Pain Sensitivity In Individuals With Low Back Pain (NCT01168999)

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Bialosky, Joel E; George, Steven Z; Horn, Maggie E; Price, Donald D; Staud, Roland; Robinson, Michael E

2013-01-01

Spinal Manipulative Therapy (SMT) is effective for some individuals experiencing low back pain (LBP); however, the mechanisms are not established regarding the role of placebo. SMT is associated with changes in pain sensitivity suggesting related altered central nervous system response or processing of afferent nociceptive input. Placebo is also associated with changes in pain sensitivity and the efficacy of SMT for changes in pain sensitivity beyond placebo has not been adequately considered. We randomly assigned 110 participants with LBP to receive SMT, placebo SMT, placebo SMT with the instructional set, “The manual therapy technique you will receive has been shown to significantly reduce low back pain in some people”, or no intervention. Participants receiving the SMT and placebo SMT received their assigned intervention 6 times over two weeks. Pain sensitivity was assessed prior to and immediately following the assigned intervention during the first session. Clinical outcomes were assessed at baseline and following two weeks of participation in the study. Immediate attenuation of suprathreshold heat response was greatest following SMT (p= 0.05, partial η2= 0.07). Group dependent differences were not observed for changes in pain intensity and disability at two week. Participant satisfaction was greatest following the enhanced placebo SMT. PMID:24361109

Short-term changes in neck pain, widespread pressure pain sensitivity, and cervical range of motion after the application of trigger point dry needling in patients with acute mechanical neck pain: a randomized clinical trial.

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Mejuto-Vázquez, María J; Salom-Moreno, Jaime; Ortega-Santiago, Ricardo; Truyols-Domínguez, Sebastián; Fernández-de-Las-Peñas, César

2014-04-01

Randomized clinical trial. To determine the effects of trigger point dry needling (TrPDN) on neck pain, widespread pressure pain sensitivity, and cervical range of motion in patients with acute mechanical neck pain and active trigger points in the upper trapezius muscle. TrPDN seems to be effective for decreasing pain in individuals with upper-quadrant pain syndromes. Potential effects of TrPDN for decreasing pain and sensitization in individuals with acute mechanical neck pain are needed. Methods Seventeen patients (53% female) were randomly assigned to 1 of 2 groups: a single session of TrPDN or no intervention (waiting list). Pressure pain thresholds over the C5-6 zygapophyseal joint, second metacarpal, and tibialis anterior muscle; neck pain intensity; and cervical spine range-of-motion data were collected at baseline (pretreatment) and 10 minutes and 1 week after the intervention by an assessor blinded to the treatment allocation of the patient. Mixed-model analyses of variance were used to examine the effects of treatment on each outcome variable. Patients treated with 1 session of TrPDN experienced greater decreases in neck pain, greater increases in pressure pain threshold, and higher increases in cervical range of motion than those who did not receive an intervention at both 10 minutes and 1 week after the intervention (Ppain intensity and widespread pressure pain sensitivity, and also increase active cervical range of motion, in patients with acute mechanical neck pain. Changes in pain, pressure pain threshold, and cervical range of motion surpassed their respective minimal detectable change values, supporting clinically relevant treatment effects. Level of Evidence Therapy, level 1b-.

Contextual modulation of pain sensitivity utilising virtual environments.

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Smith, Ashley; Carlow, Klancy; Biddulph, Tara; Murray, Brooke; Paton, Melissa; Harvie, Daniel S

2017-05-01

Investigating psychological mechanisms that modulate pain, such as those that might be accessed by manipulation of context, is of great interest to researchers seeking to better understand and treat pain. The aim of this study was to better understand the interaction between pain sensitivity, and contexts with inherent emotional and social salience - by exploiting modern immersive virtual reality (VR) technology. A within-subjects, randomised, double-blinded, repeated measures (RM) design was used. In total, 25 healthy participants were exposed to neutral, pleasant, threatening, socially positive and socially negative contexts, using an Oculus Rift DK2. Pressure pain thresholds (PPTs) were recorded in each context, as well as prior to and following the procedure. We also investigated whether trait anxiety and pain catastrophisation interacted with the relationship between the different contexts and pain. Pressure pain sensitivity was not modulated by context ( p  = 0.48). Anxiety and pain catastrophisation were not significantly associated with PPTs, nor did they interact with the relationship between context and PPTs. Contrary to our hypothesis, socially and emotionally salient contexts did not influence pain thresholds. In light of other research, we suggest that pain outcomes might only be tenable to manipulation by contextual cues if they specifically manipulate the meaning of the pain-eliciting stimulus, rather than manipulate psychological state generally - as per the current study. Future research might exploit immersive VR technology to better explore the link between noxious stimuli and contexts that directly alter its threat value.

The Role of Chronic Psychosocial Stress in Explaining Racial Differences in Stress Reactivity and Pain Sensitivity.

Science.gov (United States)

Gordon, Jennifer L; Johnson, Jacqueline; Nau, Samantha; Mechlin, Beth; Girdler, Susan S

To examine the role of psychosocial factors in mediating the relationship between African American (AA) race and both increased pain sensitivity and blunted stress reactivity. Participants included 133 AA and non-Hispanic white (nHW) individuals (mean [SD] age, 37 [9]) matched for age, sex, and socioeconomic status. Participants underwent mental stress testing (Trier Social Stress Test) while cardiovascular, hemodynamic, and neuroendocrine reactivity were measured. Participants completed questionnaires assessing potential sources of psychosocial stress and were tested for pain responses to cold pain and the temporal summation of heat pulses. Mediation analyses were used to determine the extent to which exposure to psychosocial stress accounted for the observed racial differences in stress reactivity and pain. Chronic stress exposure and reactivity to mental stress was largely similar among AAs and nHWs; however, AAs exhibited heightened pain to both cold (p = .012) and heat (p = .004). Racial differences in the relationship between stress reactivity and pain were also observed: while greater stress reactivity was associated with decreased pain among nHWs, reactivity was either unrelated to or even positively associated with pain among AAs (e.g., r = -.21 among nHWs and r = .41 among AAs for stroke volume reactivity and cold pressor intensity). Adjusting for minor racial differences in chronic psychosocial stress did not change these findings. Accounting for psychosocial factors eliminated racial differences in stress reactivity but not racial differences in sensitivity to experimental pain tasks. Increased exposure to chronic stress may not explain AAs' increased pain sensitivity in laboratory settings.

Cluster subgroups based on overall pressure pain sensitivity and psychosocial factors in chronic musculoskeletal pain: Differences in clinical outcomes.

Science.gov (United States)

Almeida, Suzana C; George, Steven Z; Leite, Raquel D V; Oliveira, Anamaria S; Chaves, Thais C

2018-05-17

We aimed to empirically derive psychosocial and pain sensitivity subgroups using cluster analysis within a sample of individuals with chronic musculoskeletal pain (CMP) and to investigate derived subgroups for differences in pain and disability outcomes. Eighty female participants with CMP answered psychosocial and disability scales and were assessed for pressure pain sensitivity. A cluster analysis was used to derive subgroups, and analysis of variance (ANOVA) was used to investigate differences between subgroups. Psychosocial factors (kinesiophobia, pain catastrophizing, anxiety, and depression) and overall pressure pain threshold (PPT) were entered into the cluster analysis. Three subgroups were empirically derived: cluster 1 (high pain sensitivity and high psychosocial distress; n = 12) characterized by low overall PPT and high psychosocial scores; cluster 2 (high pain sensitivity and intermediate psychosocial distress; n = 39) characterized by low overall PPT and intermediate psychosocial scores; and cluster 3 (low pain sensitivity and low psychosocial distress; n = 29) characterized by high overall PPT and low psychosocial scores compared to the other subgroups. Cluster 1 showed higher values for mean pain intensity (F (2,77)  = 10.58, p cluster 3, and cluster 1 showed higher values for disability (F (2,77)  = 3.81, p = 0.03) compared with both clusters 2 and 3. Only cluster 1 was distinct from cluster 3 according to both pain and disability outcomes. Pain catastrophizing, depression, and anxiety were the psychosocial variables that best differentiated the subgroups. Overall, these results call attention to the importance of considering pain sensitivity and psychosocial variables to obtain a more comprehensive characterization of CMP patients' subtypes.

Pain sensitivity and healing of hot-iron cattle brands.

Science.gov (United States)

Tucker, C B; Mintline, E M; Banuelos, J; Walker, K A; Hoar, B; Varga, A; Drake, D; Weary, D M

2014-12-01

Hot-iron branding is painful for cattle, but little is known about the duration of or effective methods to control this pain. This work quantified pain sensitivity and healing in branded and unbranded animals. In addition, the effects of a single injection of nonsteroidal anti-inflammatory drug (NSAID) were also considered; this has been suggested as practical method of mitigating pain in the hours after the procedure. Calves (mean±SE, 126±2.2 d and 112±2.8 kg) were hot-iron branded and allocated to 1 of 4 treatments: branded with or without flunixin meglumine (intravenous; 1.1 mg/kg) and unbranded with or without this NSAID (n=12/treatment). Pain sensitivity was assessed by applying a known and increasing force with a von Frey anesthesiometer in the center of the brand (or equivalent area in nonbranded treatments) until animals showed a behavioral response. Healing was measured with a 6-point scale (1=fresh brand and 6=no scabbing and fully repigmented). These measures, along with weight gain and surface temperature, were recorded 1, 2, 7, 14, 21, 28, 35, 42, 56, and 71 d after branding. Lying behavior was recorded with loggers from the day before to d 27 after branding. Brand wounds were more painful than nonbranded tissue (Pbranding (e.g., d 7; 113±36 g of force for Brand vs. 449±23 g force for No brand, mean±SE) but persisted until d 71 (380±37 g force for Brand vs. 453±23 g of force for No brand, mean±SE); only 67% of brands were fully regimented or healed by this time. The first fully healed brand was identified 8 wk after the procedure. Giving a single injection of flunixin had no brand-specific effects on sensitivity, surface temperature, or healing but improved weight gain in the days after branding in all treated groups (flunixin×brand×day, Pbranding but tended to spend more time lying on d 15 and 26 after the procedure. The magnitude of these differences is small, less than the day-to-day variation, and not brand specific. In summary, brand

Pain Sensitization Associated with Non-Response Following Physiotherapy in People with Knee Osteoarthritis.

Science.gov (United States)

O'Leary, Helen; Smart, Keith M; Moloney, Niamh A; Blake, Catherine; Doody, Catherine M

2018-05-22

In knee osteoarthritis (OA) pain sensitization has been linked to a more severe symptomatology, but the prognostic implications of pain sensitivity in people undergoing conservative treatment such as physiotherapy are not established. This study aimed to prospectively investigate the association between features of pain sensitization and clinical outcome (non-response) following guideline-based physiotherapy in people with knee OA. Participants (n=156) with moderate/severe knee OA were recruited from secondary care. All participants completed self-administered questionnaires and underwent quantitative sensory testing (QST) at baseline, thereby establishing subjective and objective measures of pain sensitization. Participants (n=134) were later classified following a physiotherapy intervention, using treatment responder criteria (responder/non-responder). QST data was reduced to a core set of latent variables using principal component analysis. A hierarchical logistic regression model was constructed to investigate if features related to pain sensitization predicted non-response after controlling for other known predictors of poor outcome in knee OA. Higher temporal summation (TS) (OR 2.00, 95% CI 1.23 to 3.27) and lower pressure pain thresholds (PPT) (OR 0.48, 95% CI 0.29 to 0.81) emerged as robust predictors of non-response following physiotherapy, along with a higher comorbidity score. The model demonstrated high sensitivity (87.8%) but modest specificity (52.3%). The independent relationship between pain sensitization and non-response may indicate an underlying explanatory association between neuroplastic changes in nociceptive processing and the maintenance of on-going pain and disability in knee OA pain. These preliminary results suggest interventions targeting pain sensitization may warrant future investigation in this population.

Gender expression, sexual orientation and pain sensitivity in women

OpenAIRE

Vigil, Jacob M; Rowell, Lauren N; Lutz, Charlotte

2014-01-01

BACKGROUND: Despite a growing body of literature investigating sex differences with regard to pain, surprisingly little research has been conducted on the influence of various aspects of self-identity, including gender expression and sexual orientation, on pain sensitivity within each sex, particularly among women. In men, dispositional femininity is linked to greater clinical pain and trait masculinity is associated with higher pain thresholds.OBJECTIVES: To examine whether gender expression...

Decreased pain sensitivity due to trimethylbenzene exposure ...

Science.gov (United States)

Traditionally, human health risk assessments have relied on qualitative approaches for hazard identification, often using the Hill criteria and weight of evidence determinations to integrate data from multiple studies. Recently, the National Research Council has recommended the development of quantitative approaches for evidence integration, including the application of meta-analyses. The following hazard identification case study applies qualitative as well as meta-analytic approaches to trimethylbenzene (TMB) isomers exposure and the potential neurotoxic effects on pain sensitivity. In the meta-analytic approach, a pooled effect size is calculated, after consideration of multiple confounding factors, in order to determine whether the entire database under consideration indicates that TMBs are likely to be a neurotoxic hazard. The pain sensitivity studies included in the present analyses initially seem discordant in their results: effects on pain sensitivity are seen immediately after termination of exposure, appear to resolve 24 hours after exposure, and then reappear 50 days later following foot-shock. Qualitative consideration of toxicological and toxicokinetic characteristics of the TMB isomers suggests that the observed differences between studies are due to testing time and can be explained through a complete consideration of the underlying biology of the effect and the nervous system as a whole. Meta-analyses and –regressions support this conclus

Increased pain sensitivity but normal function of exercise induced analgesia in hip and knee osteoarthritis - treatment effects of neuromuscular exercise and total joint replacement

DEFF Research Database (Denmark)

Kosek, E; Roos, Ewa M.; Ageberg, E

2013-01-01

To assess exercise induced analgesia (EIA) and pain sensitivity in hip and knee osteoarthritis (OA) and to study the effects of neuromuscular exercise and surgery on these parameters.......To assess exercise induced analgesia (EIA) and pain sensitivity in hip and knee osteoarthritis (OA) and to study the effects of neuromuscular exercise and surgery on these parameters....

Gender differences in pain and secondary hyperalgesia after heat/capsaicin sensitization in healthy volunteers

DEFF Research Database (Denmark)

Jensen, Magnus Thorsten; Petersen, Karin Lottrup

2006-01-01

differences in development of secondary hyperalgesia. Cutaneous hyperalgesia was induced with the heat/capsaicin sensitization model. Outcome measures were areas of secondary hyperalgesia to brush and von Frey hair stimulation after heat and capsaicin sensitization, rating of pain during heat....../capsaicin sensitization, and heat pain detection thresholds. There was a trend toward smaller areas of secondary hyperalgesia in women. After adjusting for estimated gender differences in forearm surface area, areas to brush but not von Frey hair stimulation after capsaicin sensitization were larger in women. Peak pain......, but not total pain, during prolonged noxious thermal stimulation was higher in women. There was no gender difference in pain ratings during capsaicin sensitization or in heat pain detection thresholds. The results provided only limited support to the hypothesis that gender differences in clinical pain syndromes...

Pain sensitivity is inversely related to regional grey matter density in the brain.

Science.gov (United States)

Emerson, Nichole M; Zeidan, Fadel; Lobanov, Oleg V; Hadsel, Morten S; Martucci, Katherine T; Quevedo, Alexandre S; Starr, Christopher J; Nahman-Averbuch, Hadas; Weissman-Fogel, Irit; Granovsky, Yelena; Yarnitsky, David; Coghill, Robert C

2014-03-01

Pain is a highly personal experience that varies substantially among individuals. In search of an anatomical correlate of pain sensitivity, we used voxel-based morphometry to investigate the relationship between grey matter density across the whole brain and interindividual differences in pain sensitivity in 116 healthy volunteers (62 women, 54 men). Structural magnetic resonance imaging (MRI) and psychophysical data from 10 previous functional MRI studies were used. Age, sex, unpleasantness ratings, scanner sequence, and sensory testing location were added to the model as covariates. Regression analysis of grey matter density across the whole brain and thermal pain intensity ratings at 49°C revealed a significant inverse relationship between pain sensitivity and grey matter density in bilateral regions of the posterior cingulate cortex, precuneus, intraparietal sulcus, and inferior parietal lobule. Unilateral regions of the left primary somatosensory cortex also exhibited this inverse relationship. No regions showed a positive relationship to pain sensitivity. These structural variations occurred in areas associated with the default mode network, attentional direction and shifting, as well as somatosensory processing. These findings underscore the potential importance of processes related to default mode thought and attention in shaping individual differences in pain sensitivity and indicate that pain sensitivity can potentially be predicted on the basis of brain structure. Copyright © 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

High pain sensitivity is distinct from high susceptibility to non-painful sensory input at threshold level.

Science.gov (United States)

Hummel, Thomas; Springborn, Maria; Croy, Ilona; Kaiser, Jochen; Lötsch, Jörn

2011-04-01

Individuals may differ considerably in their sensitivity towards various painful stimuli supporting the notion of a person as stoical or complaining about pain. Molecular and functional imaging research provides support that this may extend also to other sensory qualities. Whether a person can be characterized as possessing a generally high or low sensory acuity is unknown. This was therefore assessed with thresholds to painful and non-painful stimuli, with a focus on chemical stimuli that besides pain may evoke clearly non-painful sensations such as taste or smell. In 36 healthy men and 78 women (ages 18 to 52 years), pain thresholds to chemo-somatosensory (intranasal gaseous CO(2)) and electrical stimuli (cutaneous stimulation) were significantly correlated (ρ(2)=0.2268, psensory qualities, i.e., for the rose-like odor phenyl ethyl alcohol and gustatory thresholds for sour (citric acid) and salty (NaCl). Similarly, pain clusters showed no differences in thresholds to other stimuli. Moreover, no clustering was obtained for thresholds to both painful and non-painful stimuli together. Thus, individuals could not be characterized as highly sensitive (or insensitive) to all chemical stimuli no matter of evoking pain. This suggests that pain is primarily a singular sensory perception distinct from others such as olfaction or taste. Copyright © 2011 Elsevier B.V. All rights reserved.

Assessment of pain sensitivity in patients with deep bite and sex- and age-matched controls

DEFF Research Database (Denmark)

Sonnesen, Ane Liselotte; Svensson, Peter

2011-01-01

AIMS: To compare pain sensitivity between deep bite patients and a sex- and age-matched control group with normal occlusion. METHODS: Pain sensitivity was assessed by injections of the excitatory amino acid glutamate into the masseter and brachioradialis muscles. Intensity of glutamate-evoked pai...... of gender-related differences in somatosensory sensitivity and for the first time indicate that subjects with deep bite may be more sensitive to glutamate-evoked pain and thermal stimuli.......AIMS: To compare pain sensitivity between deep bite patients and a sex- and age-matched control group with normal occlusion. METHODS: Pain sensitivity was assessed by injections of the excitatory amino acid glutamate into the masseter and brachioradialis muscles. Intensity of glutamate-evoked pain...

Central sensitization as the mechanism underlying pain in joint hypermobility syndrome/Ehlers-Danlos syndrome, hypermobility type.

Science.gov (United States)

Di Stefano, G; Celletti, C; Baron, R; Castori, M; Di Franco, M; La Cesa, S; Leone, C; Pepe, A; Cruccu, G; Truini, A; Camerota, F

2016-09-01

Patients with joint hypermobility syndrome/Ehlers-Danlos syndrome, hypermobility type (JHS/EDS-HT) commonly suffer from pain. How this hereditary connective tissue disorder causes pain remains unclear although previous studies suggested it shares similar mechanisms with neuropathic pain and fibromyalgia. In this prospective study seeking information on the mechanisms underlying pain in patients with JHS/EDS-HT, we enrolled 27 consecutive patients with this connective tissue disorder. Patients underwent a detailed clinical examination, including the neuropathic pain questionnaire DN4 and the fibromyalgia rapid screening tool. As quantitative sensory testing methods, we included thermal-pain perceptive thresholds and the wind-up ratio and recorded a standard nerve conduction study to assess non-nociceptive fibres and laser-evoked potentials, assessing nociceptive fibres. Clinical examination and diagnostic tests disclosed no somatosensory nervous system damage. Conversely, most patients suffered from widespread pain, the fibromyalgia rapid screening tool elicited positive findings, and quantitative sensory testing showed lowered cold and heat pain thresholds and an increased wind-up ratio. While the lack of somatosensory nervous system damage is incompatible with neuropathic pain as the mechanism underlying pain in JHS/EDS-HT, the lowered cold and heat pain thresholds and increased wind-up ratio imply that pain in JHS/EDS-HT might arise through central sensitization. Hence, this connective tissue disorder and fibromyalgia share similar pain mechanisms. WHAT DOES THIS STUDY ADD?: In patients with JHS/EDS-HT, the persistent nociceptive input due to joint abnormalities probably triggers central sensitization in the dorsal horn neurons and causes widespread pain. © 2016 European Pain Federation - EFIC®

Pain modulatory phenotypes differentiate subgroups with different clinical and experimental pain sensitivity

DEFF Research Database (Denmark)

Vaegter, Henrik B.; Graven-Nielsen, Thomas

2016-01-01

between subgroups. Cuff algometry was performed on lower legs in 400 chronic pain patients to assess pressure pain threshold (cPPT), pressure pain tolerance (cPTT), temporal summation of pain (TSP: increase in pain scores to ten repeated stimulations), and conditioned pain modulation (CPM: increase in c......PPT during cuff pain conditioning on the contralateral leg). Heat detection (HDT) and heat pain thresholds (HPT) at clinical painful and non-painful body areas were assessed. Based on TSP and CPM four distinct groups were formed: Group 1 (n=85) had impaired CPM and facilitated TSP. Group 2 (n=148) had...... impaired CPM and normal TSP. Group 3 (n=45) had normal CPM and facilitated TSP. Group 4 (n=122) had normal CPM and normal TSP. Group 1 showed more pain regions compared with the other three groups (PCPM and facilitated TSP plays an important role in widespread pain. Group 1...

The Associations between Pain Sensitivity and Knee Muscle Strength in Healthy Volunteers

DEFF Research Database (Denmark)

Henriksen, Marius; Klokker, Louise; Bartholdy, Cecilie

2013-01-01

lateralis, deltoid, and infrapatellar fat pad. Quadriceps and hamstring muscle strength was assessed isometrically at 60-degree knee flexion using a dynamometer. Associations between pain sensitivity and muscle strength were investigated using multiple regressions including age, gender, and body mass index...... as covariates. Results. Knee extension strength was associated with computer-controlled PPT on the vastus lateralis muscle. Computer-controlled PPTs were significantly correlated between sites (r > 0.72) and with cuff PPT (r > 0.4). Saline induced pain intensity and duration were correlated between sites (r > 0......Objectives. To investigate associations between muscle strength and pain sensitivity among healthy volunteers and associations between different pain sensitivity measures. Methods. Twenty-eight healthy volunteers (21 females) participated. Pressure pain thresholds (PPTs) were obtained from 1...

Effects of intravenous propranolol on heat pain sensitivity in healthy men.

Science.gov (United States)

Schweinhardt, P; Abulhasan, Y B; Koeva, V; Balderi, T; Kim, D J; Alhujairi, M; Carli, F

2013-05-01

Clinical studies have shown opioid-sparing effects of β-adrenergic antagonists perioperatively and β-blockers are being investigated for chronic musculoskeletal pain. However, the direct analgesic effects of β-blockers have rarely been examined in healthy humans. In a randomized, counter-balanced, double-blind, within-subject crossover design, we tested the effect of the lipophilic β-blocker propranolol (0.035 mg/kg body weight i.v.) on heat pain sensitivity in 39 healthy males, compared with placebo. To test for peripheral versus central effects, the peripherally acting β-blocker sotalol was also examined. Experimental stimuli were brief superficial noxious heat stimuli applied to the volar forearm. Non-painful cold stimuli were included to test for specificity. Sedation, mood and anxiety were assessed to investigate potential mechanisms underlying any analgesic effect. β-blocker effects on blood pressure were incorporated into the analysis because of a known inverse relationship between pain sensitivity and systolic blood pressure. Propranolol significantly decreased perceived intensity of heat pain stimuli but only in participants with small propranolol-induced blood pressure decreases. Even in this group, the effect was small (4%). Propranolol did not influence perceived intensity of non-noxious stimuli and had no effect on sedation, anxiety or mood. Sotalol did not influence heat pain sensitivity. Propranolol decreased pain sensitivity but its analgesic effects were small and counteracted by blood pressure decreases. The analgesic effects were not mediated by peripheral β-receptor blockade, sedation, mood or anxiety. The small effect indicates that the utility of β-blockers for clinical pain must be related to factors that do not play a significant role for experimental pain. © 2012 European Federation of International Association for the Study of Pain Chapters.

Increasing nursing treatment for pediatric procedural pain.

Science.gov (United States)

Bice, April A; Gunther, Mary; Wyatt, Tami

2014-03-01

Procedural pain management is an underused practice in children. Despite the availability of efficacious treatments, many nurses do not provide adequate analgesia for painful interventions. Complementary therapies and nonpharmacologic interventions are additionally essential to managing pain. Owing to the increasing awareness of inadequate nursing utilization of pharmacologic measures for procedural pain, this paper focuses only on analgesic treatments. The aim of this review was to examine how varying degrees of quality improvement affect nursing utilization of treatments for routine pediatric procedural pain. A comprehensive search of databases including Cinahl, Medline/Pubmed, Web of Science, Google Scholar, Psycinfo, and Cochrane Library was performed. Sixty-two peer-reviewed research articles were examined. Ten articles focusing on quality improvement in pediatric pain management published in English from 2001 to 2011 were included. Three themes emerged: 1) increasing nursing knowledge; 2) nursing empowerment; and 3) protocol implementation. Research critique was completed with the use of guidelines and recommendations from Creswell (2009) and Garrard (2011). The literature reveals that nurses still think that pediatric pain management is essential. Quality improvement increases nursing utilization of procedural pain treatments. Although increasing nursing knowledge improves pediatric pain management, it appears that nursing empowerment and protocol implementation increase nursing compliance more than just education alone. Nurses providing pain management can enhance their individual practice with quality improvement measures that may increase nursing adherence to institutional and nationally recommended pediatric procedural pain management guidelines. Copyright © 2014 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

Intra-Articular Analgesia and Steroid Reduce Pain Sensitivity in Knee OA Patients

DEFF Research Database (Denmark)

Jørgensen, Tanja Schjødt; Graven-Nielsen, Thomas; Ellegaard, Karen

2014-01-01

Objectives. To assess the effects of intra-articular therapy on pain sensitivity in the knee and surrounding tissues in knee OA patients. Methods. Twenty-five knee OA patients with symptomatic knee OA were included in this interventional cohort study. Pressure pain thresholds (PPT) were recorded...... muscles (control site). Results. Significantly increased PPTs were found following intra-articular injection, at both the knee (P effects were sustained for two weeks, and at some points the effect was even greater at two weeks (P 

Inhibition of c-Kit signaling is associated with reduced heat and cold pain sensitivity in humans.

Science.gov (United States)

Ceko, Marta; Milenkovic, Nevena; le Coutre, Philipp; Westermann, Jörg; Lewin, Gary R

2014-07-01

The tyrosine kinase receptor c-Kit is critically involved in the modulation of nociceptive sensitivity in mice. Ablation of the c-Kit gene results in hyposensitivity to thermal pain, whereas activation of c-Kit produces hypersensitivity to noxious heat, without altering sensitivity to innocuous mechanical stimuli. In this study, we investigated the role of c-Kit signaling in human pain perception. We hypothesized that subjects treated with Imatinib or Nilotinib, potent inhibitors of tyrosine kinases including c-Kit but also Abl1, PDFGFRα, and PDFGFRβ, that are used to treat chronic myeloid leukemia (CML), would experience changes in thermal pain sensitivity. We examined 31 asymptomatic CML patients (14 male and 17 female) receiving Imatinib/Nilotinib treatment and compared them to 39 age- and sex-matched healthy controls (12 male and 27 female). We used cutaneous heat and cold stimulation to test normal and noxious thermal sensitivity, and a grating orientation task to assess tactile acuity. Thermal pain thresholds were significantly increased in the Imatinib/Nilotinib-treated group, whereas innocuous thermal and tactile thresholds were unchanged compared to those in the control group. In conclusion, our findings suggest that the biological effects of c-Kit inhibition are comparable in mice and humans in that c-Kit activity is required to regulate thermal pain sensitivity but does not affect innocuous thermal and mechanical sensation. The effect on experimental heat pain observed in our study is comparable to those of several common analgesics; thus modulation of the c-Kit pathway can be used to specifically modulate noxious heat and cold sensitivity in humans. Copyright © 2014 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Thermal and mechanical pain sensitization in patients with osteoarthritis of the knee.

Science.gov (United States)

Bevilaqua-Grossi, Debora; Zanin, Marilia; Benedetti, Camila; Florencio, Lidiane; Oliveira, Anamaria

2018-02-26

The aim was to assess sensitization using quantitative sensory testing in mechanical and thermal modes in individuals with and without osteoarthritis (OA) of the knee. Pain thresholds were correlated with functionality, symptoms of depression and intensity of pain. Thirty control volunteers and 30 patients with OA of the knee were assessed. Punctate pain thresholds using Von Frey filaments and thermal pain thresholds using a Thermal Sensory Analyzer were evaluated in the periarticular region of the knee and forearm. Using a digital pressure algometer, pressure pain thresholds were assessed in the periarticular region of the knee and on the root exit zone on the lumbar and sacral spine. Punctate, pressure, and thermal pain thresholds differed significantly between participants with and without OA (p pain sensitization. Pressure pain thresholds also showed moderate and negative correlations with data on functionality, symptoms of depression and intensity of pain (-0.36  -0.56), contributing up to 30% of their variability. Allodynia and hyperalgesia were demonstrated in the OA group, suggesting central sensitization in patients with mild to moderate severity of joint damage. Correlation between mechanical hypersensitivity and psychosocial factors seems to be small, despite of its significance.

Increased wind-up to heat pain in women with a childhood history of functional abdominal pain.

Science.gov (United States)

Dengler-Crish, Christine M; Bruehl, Stephen; Walker, Lynn S

2011-04-01

Idiopathic or functional abdominal pain (FAP) is common in school-age children and typically reflects a functional gastrointestinal disorder (FGID). FGIDs in adults have been distinguished by enhanced responses of the central nervous system to pain stimuli, known as central sensitization. This study investigated whether adolescents and young adults with a history of pediatric FAP (n=144), compared with well control subjects (n=78), showed enhanced central sensitization demonstrated by greater temporal summation (wind-up) to brief, repetitive heat pulses. We also assessed the role of gender and trait anxiety in wind-up to heat pain. Women with a history of FAP showed greater wind-up to heat pain than men with a history of FAP (Ppain was ongoing at follow-up and those whose pain had resolved. Although anxiety was significantly higher in the FAP group compared with control subjects (Ppain associated with enhanced central nervous system responses to pain stimuli. Young women with a childhood history of functional abdominal pain may have a long-term vulnerability to pain that is associated with enhanced responses of the central nervous system to pain stimuli. Copyright © 2010 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Pain sensitivity and pericranial tenderness in children with tension-type headache: a controlled study

DEFF Research Database (Denmark)

Soee, ABL; Skov, L; Kreiner, S

2013-01-01

To compare tenderness and pain sensitivity in children (aged 7-17 years) with tension-type headache (TTH) and healthy controls using total tenderness score (TTS), pressure pain threshold (PPT), and pain perceived at suprapressure pain threshold (supraPPT).......To compare tenderness and pain sensitivity in children (aged 7-17 years) with tension-type headache (TTH) and healthy controls using total tenderness score (TTS), pressure pain threshold (PPT), and pain perceived at suprapressure pain threshold (supraPPT)....

Pain sensitivity and pericranial tenderness in children with tension-type headache: a controlled study

Directory of Open Access Journals (Sweden)

Soee ABL

2013-06-01

Full Text Available Ann-Britt L Soee,1 Liselotte Skov,1 Svend Kreiner,4 Birte Tornoe,1,2 Lise L Thomsen3 1Department of Paediatrics, Children's Headache Clinic, Copenhagen University Hospital Herlev, Copenhagen, Denmark; 2Department of Physiotherapy, Medical Department O, Copenhagen University Hospital Herlev, Copenhagen, Denmark; 3Department of Neuropediatrics, Juliane Marie Centre, Copenhagen University Hospital Rigshospitalet, Copenhagen Denmark; 4Department of Biostatistics, University of Copenhagen, Copenhagen, Denmark Purpose: To compare tenderness and pain sensitivity in children (aged 7–17 years with tension-type headache (TTH and healthy controls using total tenderness score (TTS, pressure pain threshold (PPT, and pain perceived at suprapressure pain threshold (supraPPT. Patients and methods: Twenty-three children with frequent episodic TTH, 36 with chronic TTH, and 57 healthy controls were included. TTS was measured bilaterally at seven pericranial myofascial structures. PPT and supraPPT were assessed in the finger, m. temporalis, and m. trapezius by a Somedic® algometer. SupraPPT was defined as the pain perceived at a stimulus calculated as the individual site-specific PPT + 50%. Statistics: The effect of group, sex, age, headache frequency, intensity, and years on TTS, PPT, and supraPPT was analyzed by general linear models. Confirmatory factor analysis was analyzed for mutual relations between measurements. Results and conclusion: Tenderness increased uniformly in both frequent episodic TTH (median 14; interquartile range [IQR] 10–18; P < 0.001 and chronic TTH (median 13; IQR 9–20; P < 0.001 compared to controls (median 5, IQR 3–11. However, the children with frequent episodic TTH and chronic TTH did not show significantly increased sensitivity when measured by PPT or supraPPT. Factor analysis confirmed that the site-specific measurements depended on general latent variables. Consequently, the PPT and supraPPT tests can be assumed to measure

High frequency electrical stimulation concurrently induces central sensitization and ipsilateral inhibitory pain modulation.

Science.gov (United States)

Vo, L; Drummond, P D

2013-03-01

In healthy humans, analgesia to blunt pressure develops in the ipsilateral forehead during various forms of limb pain. The aim of the current study was to determine whether this analgesic response is induced by ultraviolet B radiation (UVB), which evokes signs of peripheral sensitization, or by high-frequency electrical stimulation (HFS), which triggers signs of central sensitization. Before and after HFS and UVB conditioning, sensitivity to heat and to blunt and sharp stimuli was assessed at and adjacent to the treated site in the forearm. In addition, sensitivity to blunt pressure was measured bilaterally in the forehead. The effect of ipsilateral versus contralateral temple cooling on electrically evoked pain in the forearm was then examined, to determine whether HFS or UVB conditioning altered inhibitory pain modulation. UVB conditioning triggered signs of peripheral sensitization, whereas HFS conditioning triggered signs of central sensitization. Importantly, ipsilateral forehead analgesia developed after HFS but not UVB conditioning. In addition, decreases in electrically evoked pain at the HFS-treated site were greater during ipsilateral than contralateral temple cooling, whereas decreases at the UVB-treated site were similar during both procedures. HFS conditioning induced signs of central sensitization in the forearm and analgesia both in the ipsilateral forehead and the HFS-treated site. This ipsilateral analgesia was not due to peripheral sensitization or other non-specific effects, as it failed to develop after UVB conditioning. Thus, the supra-spinal mechanisms that evoke central sensitization might also trigger a hemilateral inhibitory pain modulation process. This inhibitory process could sharpen the boundaries of central sensitization or limit its spread. © 2012 European Federation of International Association for the Study of Pain Chapters.

Lack of influence of GTP cyclohydrolase gene (GCH1 variations on pain sensitivity in humans

Directory of Open Access Journals (Sweden)

Dionne Raymond A

2007-03-01

Full Text Available Abstract Objectives To assess the effect of variations in GTP cyclohydrolase gene (GCH1 on pain sensitivity in humans. Methods Thermal and cold pain sensitivity were evaluated in a cohort of 735 healthy volunteers. Among this cohort, the clinical pain responses of 221 subjects after the surgical removal of impacted third molars were evaluated. Genotyping was done for 38 single nucleotide polymorphisms (SNPs whose heterozygosity > 0.2 in GCH1. Influence of the genetic variations including SNPs and haplotypes on pain sensitivity were analyzed. Results Minor allele frequencies and linkage disequilibrium show significant differences in European Americans, African Americans, Hispanic Americans and Asian Americans. Association analyses in European Americans do not replicate the previously reported important influence of GCH1 variations on pain sensitivity. Conclusion Considering population stratification, previously reported associations between GCH1 genetic variations and pain sensitivity appear weak or negligible in this well characterized model of pain.

Patients with chronic tension-type headache demonstrate increased mechano-sensitivity of the supra-orbital nerve.

Science.gov (United States)

Fernández-de-Las-Peñas, César; Coppieters, Michel W; Cuadrado, María Luz; Pareja, Juan A

2008-04-01

This study aimed to establish whether increased sensitivity to mechanical stimuli is present in neural tissues in chronic tension-type headache (CTTH). Muscle hyperalgesia is a common finding in CTTH. No previous studies have investigated the sensitivity of peripheral nerves in patients with CTTH. A blinded controlled study. Pressure pain thresholds (PPT) and pain intensity following palpation of the supra-orbital nerve (V1) were compared between 20 patients with CTTH and 20 healthy matched subjects. A pressure algometer and numerical pain rate scale were used to quantify PPT and pain to palpation. A headache diary was kept for 4 weeks to substantiate the diagnosis and record the pain history. The analysis of variance demonstrated significantly lower PPT for patients (0.86+/-0.13 kg/cm2) than controls (1.50+/-0.19 kg/cm2) (Por=0.72; P<.001). These findings reveal that mechanical hypersensitivity is not limited to muscles but also occurs in cranial nerves, and that the level of sensitization, either due to peripheral or central processes, is related to the severity of the primary headache.

Generalized and symptom-specific sensitization of chronic itch and pain.

NARCIS (Netherlands)

Laarhoven, A.I.M. van; Kraaimaat, F.W.; Wilder-Smith, O.H.G.; Kerkhof, P.C.M. van de; Cats, H.; Riel, P.L.C.M. van; Evers, A.W.M.

2007-01-01

BACKGROUND: Physicians are frequently confronted with patients reporting severe itch and pain. Particularly in patients suffering from persistent itch and pain, central and peripheral sensitization processes are assumed to be involved in the long-term maintenance and aggravation of the symptoms. The

Relationship of Corneal Pain Sensitivity With Dry Eye Symptoms in Dry Eye With Short Tear Break-Up Time.

Science.gov (United States)

Kaido, Minako; Kawashima, Motoko; Ishida, Reiko; Tsubota, Kazuo

2016-03-01

The purpose of this prospective comparative study was to investigate corneal sensitivity in subjects with unstable tear film, with and without dry eye (DE) symptoms. Forty-one eyes of 41 volunteers (mean age: 45.1 ± 9.4 years; age range, 23-57 years), with normal tear function and ocular surface except for tear stability, were studied. The eyes were divided into two groups depending on the presence or absence of DE symptoms: 21 eyes with DE symptoms (symptomatic group); and 20 eyes without DE symptoms (asymptomatic group). Three types of corneal sensitivity values were measured using a Cochet-Bonnet esthesiometer: the sensitivity for perception of touch (S-touch), the sensitivity for blinking (S-blink), and the sensitivity for pain (S-pain). Mean S-blink and S-pain were significantly higher in the symptomatic group than in the asymptomatic group (P 0.05). Corneal sensitivity for blinking and pain evoked by increased stimuli was higher in the symptomatic group (subjects with short break-up time DE) compared with subjects who have no DE symptoms despite decreased tear stability. The presence of both tear instability and hyperesthesia, rather than tear instability alone, may contribute to DE pathogenesis.

A cross-sectional study of pain sensitivity, disease-activity assessment, mental health, and fibromyalgia status in rheumatoid arthritis.

Science.gov (United States)

Joharatnam, Nalinie; McWilliams, Daniel F; Wilson, Deborah; Wheeler, Maggie; Pande, Ira; Walsh, David A

2015-01-20

Pain remains the most important problem for people with rheumatoid arthritis (RA). Active inflammatory disease contributes to pain, but pain due to non-inflammatory mechanisms can confound the assessment of disease activity. We hypothesize that augmented pain processing, fibromyalgic features, poorer mental health, and patient-reported 28-joint disease activity score (DAS28) components are associated in RA. In total, 50 people with stable, long-standing RA recruited from a rheumatology outpatient clinic were assessed for pain-pressure thresholds (PPTs) at three separate sites (knee, tibia, and sternum), DAS28, fibromyalgia, and mental health status. Multivariable analysis was performed to assess the association between PPT and DAS28 components, DAS28-P (the proportion of DAS28 derived from the patient-reported components of visual analogue score and tender joint count), or fibromyalgia status. More-sensitive PPTs at sites over or distant from joints were each associated with greater reported pain, higher patient-reported DAS28 components, and poorer mental health. A high proportion of participants (48%) satisfied classification criteria for fibromyalgia, and fibromyalgia classification or characteristics were each associated with more sensitive PPTs, higher patient-reported DAS28 components, and poorer mental health. Widespread sensitivity to pressure-induced pain, a high prevalence of fibromyalgic features, higher patient-reported DAS28 components, and poorer mental health are all linked in established RA. The increased sensitivity at nonjoint sites (sternum and anterior tibia), as well as over joints, indicates that central mechanisms may contribute to pain sensitivity in RA. The contribution of patient-reported components to high DAS28 should inform decisions on disease-modifying or pain-management approaches in the treatment of RA when inflammation may be well controlled.

Sensory and sympathetic correlates of heat pain sensitization and habituation in men and women.

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Breimhorst, M; Hondrich, M; Rebhorn, C; May, A; Birklein, F

2012-10-01

Habituation and sensitization are important behavioural responses to repeated exposure to painful stimuli, but little is known about the factors determining sensory, affective and sympathetic habituation to repeated pain stimulation in men and women. Thirty volunteers (15 women) underwent a standardized heat pain paradigm spread over 8 consecutive days. At the beginning of the experiment, personality dimensions, coping strategies and pain catastrophizing thoughts were determined. Receiving a series of 10 blocks of six painful heat stimuli a day, participants rated pain intensity and unpleasantness. Skin conductance was recorded throughout the sessions. The results show similar habituation of both the sensory and affective dimensions of pain in men and women, although skin conductance did not undergo a significant decrease across the eight days. When focusing on single daily sessions, women showed pain sensitization but sympathetic habituation, while men showed pain sensitization but stable sympathetic activation. Our findings therefore indicate that the process of long-term habituation to painful heat stimuli is a common feature in both genders, whereas men and women might differently recruit their sympathetic nervous system for short-term pain processing. This study could potentially help to better evaluate gender-specific mechanisms in pain perception. © 2012 European Federation of International Association for the Study of Pain Chapters.

Entropy as a new measure of mechanical pain sensitivity in the masseter muscle

DEFF Research Database (Denmark)

Castrillon, Eduardo; Sato, Hitoshi; Tanosoto, Tomohiro

ENTROPY AS A NEW MEASURE OF MECHANICAL PAIN SENSITIVITY IN THE MASSETER MUSCLE Author Block: E. E. Castrillon1, H. Sato2,3, T. Tanosoto4, T. Arima4, L. Baad-Hansen1, P. Svensson1, 1Clinical Oral Physiology, Århus Univ., Aarhus, Denmark, 2Dept. of Dentistry & Oral Physiology, Sch. of Med., Keio Un...... injections (Pmechanical pain sensitivity that captures new aspects of spatial characteristics and could therefore complement more classical assessments of TMD pain patients.......ENTROPY AS A NEW MEASURE OF MECHANICAL PAIN SENSITIVITY IN THE MASSETER MUSCLE Author Block: E. E. Castrillon1, H. Sato2,3, T. Tanosoto4, T. Arima4, L. Baad-Hansen1, P. Svensson1, 1Clinical Oral Physiology, Århus Univ., Aarhus, Denmark, 2Dept. of Dentistry & Oral Physiology, Sch. of Med., Keio Univ......., Tokyo, Japan, 3Japan Society for the Promotion of Sci., Tokyo, Japan, 4Dept. of Oral Rehabilitation, Graduate Sch. of Dental Med., Hokkaido Univ., Sapporo, Japan : Aim of Investigation: Manual palpation is a psychophysical technique to evaluate mechanical pain sensitivity in craniofacial muscles...

Healthy volunteers can be phenotyped using cutaneous sensitization pain models.

Directory of Open Access Journals (Sweden)

Mads U Werner

Full Text Available BACKGROUND: Human experimental pain models leading to development of secondary hyperalgesia are used to estimate efficacy of analgesics and antihyperalgesics. The ability to develop an area of secondary hyperalgesia varies substantially between subjects, but little is known about the agreement following repeated measurements. The aim of this study was to determine if the areas of secondary hyperalgesia were consistently robust to be useful for phenotyping subjects, based on their pattern of sensitization by the heat pain models. METHODS: We performed post-hoc analyses of 10 completed healthy volunteer studies (n = 342 [409 repeated measurements]. Three different models were used to induce secondary hyperalgesia to monofilament stimulation: the heat/capsaicin sensitization (H/C, the brief thermal sensitization (BTS, and the burn injury (BI models. Three studies included both the H/C and BTS models. RESULTS: Within-subject compared to between-subject variability was low, and there was substantial strength of agreement between repeated induction-sessions in most studies. The intraclass correlation coefficient (ICC improved little with repeated testing beyond two sessions. There was good agreement in categorizing subjects into 'small area' (1(st quartile [75%] responders: 56-76% of subjects consistently fell into same 'small-area' or 'large-area' category on two consecutive study days. There was moderate to substantial agreement between the areas of secondary hyperalgesia induced on the same day using the H/C (forearm and BTS (thigh models. CONCLUSION: Secondary hyperalgesia induced by experimental heat pain models seem a consistent measure of sensitization in pharmacodynamic and physiological research. The analysis indicates that healthy volunteers can be phenotyped based on their pattern of sensitization by the heat [and heat plus capsaicin] pain models.

Asymmetric dimethylarginine may mediate increased heat pain threshold in experimental chronic kidney disease.

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Kielstein, Jan T; Suntharalingam, Mayuren; Perthel, Ronny; Rong, Song; Martens-Lobenhoffer, Jens; Jäger, Kristin; Bode-Böger, Stefanie M; Nave, Heike

2012-03-01

Thermal sensitivity in uraemia is decreased. Non-selective synthetic nitric oxide synthase (NOS) inhibitors significantly attenuate thermal hyperalgesia in preclinical models. The aim of our study was to evaluate the effect of experimental uraemia, which is associated with an increase of the endogenous NOS inhibitor asymmetric dimethylarginine (ADMA), on thermal sensitivity in rats. Furthermore, we intended to study the effect of chronic ADMA infusion alone on thermal sensitivity. Male Sprague-Dawley rats (n = 54), 10 weeks old, weight 370-430 g, were randomly assigned to three groups receiving either (i) isotonic saline or (ii) ADMA via osmotic mini pumps or (iii) underwent 5/6 nephrectomy (Nx). After 14 days, 50% of all animals from all groups underwent thermal sensitivity testing and terminal blood draw. After 28 days, the remaining animals underwent the same procedures. Thermal sensitivity examination was performed by the hot-plate test, measuring time from heat exposition to first paw licking or jumping of the animal. While the median [interquartile range] latency time between heat exposition to first paw licking or jumping of the animal in the NaCl infusion group remained unchanged between Day 14 (8.4 [6.75-11.50] s) and Day 28 (7.35 [6.10-7.90] s) both, ADMA infusion and 5/6 nephrectomy tended to increase the thermal pain threshold at Day 14 (9.25 [6.55-12.18] s) and (9.50 [5.8 ± 11.0] s), respectively, compared to NaCl on Day 14 (8.4 [6.75-11.50] s). This difference became statistical significant at Day 28 where the median latency time in the ADMA group (13.10 [11.85-15.95] s) and in the 5/6 Nx group (13.50 [10.85-17.55] s) were significantly higher than in the NaCl group (7.35 [6.10-7.90] s). Induction of progressive renal failure in rats by 5/6 nephrectomy, which is accompanied by a marked increase of the serum levels of the endogenous NOS inhibitor ADMA, leads to a significantly increased heat pain threshold at 28 days. The sole infusion of ADMA into

Effects of low strength pedaling exercise on stress sensitivity and pain threshold

OpenAIRE

坂野, 裕洋

2017-01-01

　This study conducted a comparative assessment of the effects of low intensity lower limb pedaling exercise on the stress sensitivity and pain threshold in healthy subjects and those with chronic stiff neck or lower back pain. The results showed a reduction in pain threshold depending on the applied mechanical stress in both healthy and chronic pain groups. The individuals with chronic pain felt pain more intensely compared to the healthy individuals, and showed a significant reduction in pai...

Chronic whiplash and central sensitization; an evaluation of the role of a myofascial trigger points in pain modulation

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Freeman Michael D

2009-04-01

Full Text Available Abstract Objective it has been established that chronic neck pain following whiplash is associated with the phenomenon of central sensitization, in which injured and uninjured parts of the body exhibit lowered pain thresholds due to an alteration in central pain processing. it has furthermore been hypothesized that peripheral sources of nociception in the muscles may perpetuate central sensitization in chronic whiplash. the hypothesis explored in the present study was whether myofascial trigger points serve as a modulator of central sensitization in subjects with chronic neck pain. Design controlled case series. Setting outpatient chronic pain clinic. Subjects seventeen patients with chronic and intractable neck pain and 10 healthy controls without complaints of neck pain. Intervention symptomatic subjects received anesthetic infiltration of myofascial trigger points in the upper trapezius muscles and controls received the anesthetic in the thigh. Outcome measures: pre and post injection cervical range of motion, pressure pain thresholds (ppt over the infraspinatus, wrist extensor, and tibialis anterior muscles. sensitivity to light (photophobia and subjects' perception of pain using a visual analog scale (vas were also evaluated before and after injections. only the ppt was evaluated in the asymptomatic controls. Results immediate (within 1 minute alterations in cervical range of motion and pressure pain thresholds were observed following an average of 3.8 injections with 1–2 cc of 1% lidocaine into carefully identified trigger points. cervical range of motion increased by an average of 49% (p = 0.000 in flexion and 44% (p = 0.001 in extension, 47% (p = 0.000 and 28% (p Conclusion the present data suggest that myofascial trigger points serve to perpetuate lowered pain thresholds in uninjured tissues. additionally, it appears that lowered pain thresholds associated with central sensitization can be immediately reversed, even when associated

Pain sensitivity mediates the relationship between stress and headache intensity in chronic tension-type headache.

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Cathcart, Stuart; Bhullar, Navjot; Immink, Maarten; Della Vedova, Chris; Hayball, John

2012-01-01

A central model for chronic tension-type headache (CTH) posits that stress contributes to headache, in part, by aggravating existing hyperalgesia in CTH sufferers. The prediction from this model that pain sensitivity mediates the relationship between stress and headache activity has not yet been examined. To determine whether pain sensitivity mediates the relationship between stress and prospective headache activity in CTH sufferers. Self-reported stress, pain sensitivity and prospective headache activity were measured in 53 CTH sufferers recruited from the general population. Pain sensitivity was modelled as a mediator between stress and headache activity, and tested using a nonparametric bootstrap analysis. Pain sensitivity significantly mediated the relationship between stress and headache intensity. The results of the present study support the central model for CTH, which posits that stress contributes to headache, in part, by aggravating existing hyperalgesia in CTH sufferers. Implications for the mechanisms and treatment of CTH are discussed.

Hypoxia-inducible factor 1 regulates heat and cold pain sensitivity and persistence.

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Kanngiesser, Maike; Mair, Norbert; Lim, Hee-Young; Zschiebsch, Katja; Blees, Johanna; Häussler, Annett; Brüne, Bernhard; Ferreiròs, Nerea; Kress, Michaela; Tegeder, Irmgard

2014-06-01

The present study assessed the functions of the transcription factor hypoxia-inducible factor (HIF) in sensory neurons in models of acute, inflammatory, ischemic, and neuropathic pain. The alpha subunit, HIF1α, was specifically deleted in neurons of the dorsal root ganglia by mating HIF1α(fl/fl) mice with SNScre mice. SNS-HIF1α(-/-) mice were more sensitive to noxious heat and cold pain stimulation than were HIF1α(fl/fl) control mice. They also showed heightened first-phase nociceptive responses in the formalin and capsaicin tests with increased numbers of cFos-positive neurons in the dorsal horn, and intensified hyperalgesia in early phases after paw inflammation and hind limb ischemia/reperfusion. The behavioral cold and heat pain hypersensitivity was explained by increased calcium fluxes after transient receptor potential channel activation in primary sensory neurons of SNS-HIF1α(-/-) mice and lowered electrical activation thresholds of sensory fibers. SNS-HIF1α(-/-) mice however, developed less neuropathic pain after sciatic nerve injury, which was associated with an abrogation of HIF1-mediated gene up-regulation. The results suggest that HIF1α is protective in terms of acute heat and cold pain but in case of ongoing activation in injured neurons, it may promote the development of neuropathic pain. The duality of HIF1 in pain regulation may have an impact on the side effects of drugs targeting HIF1, which are being developed, for example, as anticancer agents. Specifically, in patients with cancer neuropathy, however, temporary HIF1 inhibition might provide a welcome combination of growth and pain reduction.

Relationship between self-reported pain sensitivity and pain after total knee arthroplasty: a prospective study of 71 patients 8 weeks after a standardized fast-track

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Valeberg BT

2016-09-01

Full Text Available Berit T Valeberg,1 Lise H Høvik,2 Kari H Gjeilo3–6 1Faculty of Nursing, Oslo and Akershus University College of Applied Sciences, Oslo, 2Clinic of Anaesthesia and Intensive Care Medicine, St. Olavs Hospital, Trondheim University Hospital, 3Department of Cardiothoracic Surgery, 4Department of Cardiology, 5National Competence Centre for Complex Symptom Disorders, St. Olavs Hospital, Trondheim University Hospital, 6Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway Background and purpose: This was a prospective cohort study assessing data from 71 adult patients undergoing total knee arthroplasty (TKA following a standardized fast-track program between January and July 2013. The objective was to examine the relationship between self-rated pain sensitivity, as measured by the Pain Sensitivity Questionnaire (PSQ, and postoperative pain after TKA. Methods: The baseline questionnaires, PSQ and Brief Pain Inventory, were given to the patients for self-administration at the presurgical evaluation (1–2 weeks prior to surgery. The follow-up questionnaire, Brief Pain Inventory, was administered at the first follow-up, 8 weeks after surgery. Results: A statistically significant association was found between average preoperative pain and average pain 8 weeks after surgery (P=0.001. The PSQ-minor was statistically significantly associated with average pain only for patients younger than 70 years (P=0.03. Interpretation: This is the first study to examine the relationship between pain sensitivity measured by PSQ and postoperative pain in patients after TKA. We found that a lower score on the PSQ-minor was statistically significantly associated with patients’ pain 8 weeks after TKA surgery, but only for younger patients. Further research is needed to explore whether the PSQ could be a useful screening tool for patients’ pain sensitivity in clinical settings. Keywords

Effect of Means of Problem-Oriented Physical Rehabilitation on Pain and Tactile Sensitivity and Pain Syndrome Intensity in Women with Post-Mastectomy Syndrome

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Т. Є. Одинець

2015-03-01

Full Text Available The objective of the paper is to determine the effectiveness of problem-oriented physical rehabilitation of women with post-mastectomy syndrome in terms of normalization of their sensitivity and lessening of the pain syndrome. Materials and methods. The paper provides a review of the related literary sources and empirical data analyzed and summarized, offers definitions of pain by the Visual Analogue Scale, McGill Pain Questionnaire and the Verbal Rating Scale, evaluates tactile and pain sensitivity, and uses the methods of mathematical statistics. The participants in the study were 50 women with diagnosed with the post-mastectomy syndrome and at the stage of residential treatment. Results: The developed problem-oriented physical rehabilitation experimentally proved effective by showing improvements in tactile and pain sensitivity, and pain lessening by the sensory, affective and rating scales in women with post-mastectomy syndrome at the stage of residential treatment.

Morning Versus Evening Bright Light Treatment at Home to Improve Function and Pain Sensitivity for Women with Fibromyalgia: A Pilot Study.

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Burgess, Helen J; Park, Margaret; Ong, Jason C; Shakoor, Najia; Williams, David A; Burns, John

2017-01-01

To test the feasibility, acceptability, and effects of a home-based morning versus evening bright light treatment on function and pain sensitivity in women with fibromyalgia. A single blind randomized study with two treatment arms: 6 days of a 1 hour morning light treatment or 6 days of a 1 hour evening light treatment. Function, pain sensitivity, and circadian timing were assessed before and after treatment. Participants slept at home, except for two nights in Sleep Center. Ten women meeting the American College of Rheumatology's diagnostic criteria for fibromyalgia, including normal blood test results. Self-reported function was assessed with the Fibromyalgia Impact Questionnaire (FIQ). Pain sensitivity was assessed using a heat stimulus that gave measures of threshold and tolerance. Circadian timing was assessed with the dim light melatonin onset. Both morning and evening light treatments led to improvements in function and pain sensitivity. However, only the morning light treatment led to a clinically meaningful improvement in function (>14% reduction from baseline FIQ) and morning light significantly increased pain threshold more than evening light ( P  treatment appears to be a feasible and acceptable adjunctive treatment to women with fibromyalgia. Those who undergo morning light treatment may show improvements in function and pain sensitivity. Advances in circadian timing may be one mechanism by which morning light improves pain sensitivity. Findings can inform the design of a randomized controlled trial. © 2016 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Genetic variants associated with thermal pain sensitivity in a paediatric population

NARCIS (Netherlands)

Matic, M.; Bosch, G.E. van den; Wildt, S.N. de; Tibboel, D.; Schaik, R.H. van

2016-01-01

Pain sensitivity is an inherited factor that varies strongly between individuals. We investigated whether genetic polymorphisms in the candidate genes COMT, OPRM1, OPRD1, TAOK3, TRPA1, TRPV1, and SCN9A are contributing to experimental pain variability between children. Our study included 136

Prior stress exposure increases pain behaviors in a rat model of full thickness thermal injury.

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Nyland, Jennifer E; McLean, Samuel A; Averitt, Dayna L

2015-12-01

Thermal burns among individuals working in highly stressful environments, such as firefighters and military Service Members, are common. Evidence suggests that pre-injury stress may exaggerate pain following thermal injury; however current animal models of burn have not evaluated the potential influence of pre-burn stress. This sham-controlled study evaluated the influence of prior stress exposure on post-burn thermal and mechanical sensitivity in male Sprague-Dawley rats. Rats were exposed to 20 min of inescapable swim stress or sham stress once per day for three days. Exposure to inescapable swim stress (1) increased the intensity and duration of thermal hyperalgesia after subsequent burn and (2) accelerated the onset of thermal hyperalgesia and mechanical allodynia after subsequent burn. This stress-induced exacerbation of pain sensitivity was reversed by pretreatment and concurrent treatment with the serotonin-norepinephrine reuptake inhibitor (SNRI) duloxetine. These data suggest a better understanding of mechanisms by which prior stress augments pain after thermal burn may lead to improved pain treatments for burn survivors. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

Masticatory and cervical muscle tenderness and pain sensitivity in a remote area in subjects with a temporomandibular disorder and neck disability.

Science.gov (United States)

Silveira, Anelise; Armijo-Olivo, Susan; Gadotti, Inae C; Magee, David

2014-01-01

To compare the masticatory and cervical muscle tenderness and pain sensitivity in the hand (remote region) between patients with temporomandibular disorders (TMD) and healthy controls. Twenty female subjects were diagnosed with chronic TMD, and 20 were considered healthy. Subjects completed the Neck Disability Index and Limitations of Daily Functions in a TMD questionnaire. Tenderness of the masticatory and cervical muscles and pain sensitivity in the hand were measured using an algometer. Three-way mixed analysis of variance (ANOVA) evaluated differences in muscle tenderness between groups. One-way ANOVA compared pain sensitivity in the hand between groups. Effect sizes were assessed using Cohen guidelines. Significantly increased masticatory and cervical muscle tenderness and pain sensitivity in the hand were found in subjects with TMD when compared with healthy subjects. Moderate to high effect sizes showed the clinical relevance of the findings. The results of this study have highlighted the importance of assessing TMD patients not only in the craniofacial region but also in the neck and other parts of the body. Future studies should focus on testing the effectiveness of treatments addressing the neck and the pain sensitivity in the hand in patients with TMD.

Relationship Between Dry Eye Symptoms and Pain Sensitivity

NARCIS (Netherlands)

Vehof, Jelle; Kozareva, Diana; Hysi, Pirro G.; Harris, Juliette; Nessa, Ayrun; Williams, Frances K.; Bennett, David L. H.; McMahon, Steve B.; Fahy, Samantha J.; Direk, Kenan; Spector, Tim D.; Hammond, Christopher J.

2013-01-01

IMPORTANCE Dry eye disease (DED) is common, but little is known about factors contributing to symptoms of dry eye, given the poor correlation between these symptoms and objective signs at the ocular surface. OBJECTIVE To explore whether pain sensitivity plays a role in patients' experience of DED

Clinical Interpretation of Quantitative Sensory Testing as a Measure of Pain Sensitivity in Patients with Sickle Cell Disease

OpenAIRE

Brandow, Amanda M.; Panepinto, Julie A.

2016-01-01

Patients with sickle cell disease (SCD) display significantly lower mean/median thermal and mechanical pain thresholds compared to controls. This suggests impaired pain sensitivity where stimuli produce exaggerated pain. Despite these mean/median differences, clinicians need to understand if patients meet criteria for impaired pain sensitivity. We defined thresholds for impaired cold, heat, and mechanical pain sensitivity in SCD patients. Using quantitative sensory testing (QST) we assessed c...

Pain Processing after Social Exclusion and Its Relation to Rejection Sensitivity in Borderline Personality Disorder.

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Melanie Bungert

Full Text Available There is a general agreement that physical pain serves as an alarm signal for the prevention of and reaction to physical harm. It has recently been hypothesized that "social pain," as induced by social rejection or abandonment, may rely on comparable, phylogenetically old brain structures. As plausible as this theory may sound, scientific evidence for this idea is sparse. This study therefore attempts to link both types of pain directly. We studied patients with borderline personality disorder (BPD because BPD is characterized by opposing alterations in physical and social pain; hyposensitivity to physical pain is associated with hypersensitivity to social pain, as indicated by an enhanced rejection sensitivity.Twenty unmedicated female BPD patients and 20 healthy participants (HC, matched for age and education played a virtual ball-tossing game (cyberball, with the conditions for exclusion, inclusion, and a control condition with predefined game rules. Each cyberball block was followed by a temperature stimulus (with a subjective pain intensity of 60% in half the cases. The cerebral responses were measured by functional magnetic resonance imaging. The Adult Rejection Sensitivity Questionnaire was used to assess rejection sensitivity.Higher temperature heat stimuli had to be applied to BPD patients relative to HCs to reach a comparable subjective experience of painfulness in both groups, which suggested a general hyposensitivity to pain in BPD patients. Social exclusion led to a subjectively reported hypersensitivity to physical pain in both groups that was accompanied by an enhanced activation in the anterior insula and the thalamus. In BPD, physical pain processing after exclusion was additionally linked to enhanced posterior insula activation. After inclusion, BPD patients showed reduced amygdala activation during pain in comparison with HC. In BPD patients, higher rejection sensitivity was associated with lower activation differences during

Uncertainty about the intensity of impending pain increases ensuing pain responses in congenital blindness

DEFF Research Database (Denmark)

Holten-Rossing, S.; Slimani, H.; Ptito, M.

2018-01-01

about the intensity of a pending painful stimulus affects pain differently in congenitally blind and sighted control subjects. We measured pain and anxiety in a group of 11 congenitally blind and 11 age- and sex-matched normal sighted control participants. Painful stimuli were delivered under two...... psychological conditions, whereby participants were either certain or uncertain about the intensity of a pending noxious stimuli. Although both blind and sighted participants had increased anxiety ratings in the uncertain condition, pain ratings increased only in the congenitally blind participants. Our data...

Mechano-sensitive nociceptors are required to detect heat pain thresholds and cowhage itch in human skin.

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Weinkauf, B; Dusch, M; van der Ham, J; Benrath, J; Ringkamp, M; Schmelz, M; Rukwied, R

2016-02-01

Mechano-sensitive and mechano-insensitive C-nociceptors in human skin differ in receptive field sizes and electrical excitation thresholds, but their distinct functional roles are yet unclear. After blocking the lateral femoral cutaneous nerve (NCFL) in eight healthy male subjects (3-mL Naropin(®) 1%), we mapped the skin innervation territory being anaesthetic to mechanical pin prick but sensitive to painful transcutaneous electrical stimuli. Such 'differentially anaesthetic zones' indicated that the functional innervation with mechano-sensitive nociceptors was absent but the innervation with mechano-insensitive nociceptors remained intact. In these areas, we explored heat pain thresholds, low pH-induced pain, cowhage- and histamine-induced itch, and axon reflex flare. In differentially anaesthetic skin, heat pain thresholds were above the cut-off of 50°C (non-anaesthetized skin 47 ± 0.4°C). Pain ratings to 30 μL pH 4 injections were reduced compared to non-anaesthetized skin (48 ± 9 vs. 79 ± 6 VAS; p pain. The mechano-sensitive nociceptors are crucial for cowhage-induced itch and for the assessment of heat pain thresholds. © 2015 European Pain Federation - EFIC®

Is heat pain detection threshold associated with the area of secondary hyperalgesia following brief thermal sensitization?

DEFF Research Database (Denmark)

Hansen, Morten Sejer; Wetterslev, Jørn; Pipper, Christian Bressen

2016-01-01

role in the development of secondary hyperalgesia; however, a possible association of secondary hyperalgesia following brief thermal sensitization and other heat pain models remains unknown. Our aim with this study is to investigate how close the heat pain detection threshold is associated...... with the size of the area of secondary hyperalgesia induced by the clinical heat pain model: Brief thermal sensitization. METHODS AND DESIGN: We aim to include 120 healthy participants. The participants will be tested on two separate study days with the following procedures: i) Brief thermal sensitization, ii......) heat pain detection threshold and iii) pain during thermal stimulation. Additionally, the participants will be tested with the Pain Catastrophizing Scale and Hospital Anxiety and Depression Scale questionnaires. We conducted statistical simulations based on data from our previous study, to estimate...

Sleep disturbances and severe stress as glial activators: key targets for treating central sensitization in chronic pain patients?

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Nijs, Jo; Loggia, Marco L; Polli, Andrea; Moens, Maarten; Huysmans, Eva; Goudman, Lisa; Meeus, Mira; Vanderweeën, Luc; Ickmans, Kelly; Clauw, Daniel

2017-08-01

The mechanism of sensitization of the central nervous system partly explains the chronic pain experience in many patients, but the etiological mechanisms of this central nervous system dysfunction are poorly understood. Recently, an increasing number of studies suggest that aberrant glial activation takes part in the establishment and/or maintenance of central sensitization. Areas covered: This review focused on preclinical work and mostly on the neurobiochemistry studied in animals, with limited human studies available. Glial overactivation results in a low-grade neuroinflammatory state, characterized by high levels of BDNF, IL-1β, TNF-α, which in turn increases the excitability of the central nervous system neurons through mechanisms like long-term potentiation and increased synaptic efficiency. Aberrant glial activity in chronic pain might have been triggered by severe stress exposure, and/or sleeping disturbances, each of which are established initiating factors for chronic pain development. Expert opinion: Potential treatment avenues include several pharmacological options for diminishing glial activity, as well as conservative interventions like sleep management, stress management and exercise therapy. Pharmacological options include propentofylline, minocycline, β -adrenergic receptor antagonists, and cannabidiol. Before translating these findings from basic science to clinical settings, more human studies exploring the outlined mechanisms in chronic pain patients are needed.

Validity, Sensitivity, and Responsiveness of the 11-Face Faces Pain Scale to Postoperative Pain in Adult Orthopedic Surgery Patients.

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Van Giang, Nguyen; Chiu, Hsiao-Yean; Thai, Duong Hong; Kuo, Shu-Yu; Tsai, Pei-Shan

2015-10-01

Pain is common in patients after orthopedic surgery. The 11-face Faces Pain Scale has not been validated for use in adult patients with postoperative pain. To assess the validity of the 11-face Faces Pain Scale and its ability to detect responses to pain medications, and to determine whether the sensitivity of the 11-face Faces Pain Scale for detecting changes in pain intensity over time is associated with gender differences in adult postorthopedic surgery patients. The 11-face Faces Pain Scale was translated into Vietnamese using forward and back translation. Postoperative pain was assessed using an 11-point numerical rating scale and the 11-face Faces Pain Scale on the day of surgery, and before (Time 1) and every 30 minutes after (Times 2-5) the patients had taken pain medications on the first postoperative day. The 11-face Faces Pain Scale highly correlated with the numerical rating scale (r = 0.78, p Scale is appropriate for measuring acute postoperative pain in adults. Copyright © 2015 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

Pain Sensitivity Mediates The Relationship between Stress and Headache Intensity in Chronic Tension-Type Headache

OpenAIRE

Stuart Cathcart; Navjot Bhullar; Maarten Immink; Chris Della Vedova; John Hayball

2012-01-01

BACKGROUND: A central model for chronic tension-type headache (CTH) posits that stress contributes to headache, in part, by aggravating existing hyperalgesia in CTH sufferers. The prediction from this model that pain sensitivity mediates the relationship between stress and headache activity has not yet been examined.OBJECTIVE: To determine whether pain sensitivity mediates the relationship between stress and prospective headache activity in CTH sufferers.METHOD: Self-reported stress, pain sen...

Physical pain increases interpersonal trust in females.

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Wang, C; Gao, J; Ma, Y; Zhu, C; Dong, X-W

2018-01-01

People behave and interact with others differently when experiencing physical pain. Pain has dramatic effects on one's emotional responses, cognitive functions and social interaction. However, little has been known about whether and how physical pain influences interpersonal trust in social interaction. In the present study, we examined the influence of physical pain on trusting behaviour. A total of 112 healthy participants were recruited and assigned to physical pain condition (induced by Capsaicin) and control condition (with hand cream), respectively. Thirty minutes after pain induction, three decision-making tasks were conducted to measure behaviours in social interaction, including trust and trustworthiness (trust game), non-social risk-taking (risk game) and altruism (dictator game). Results showed that physical pain increased interpersonal trust among females, but not among males. Pain did not influence non-social risk-taking, altruism or trustworthiness, as evaluated by monetary transfers in those tasks. Moreover, the effect of physical pain on interpersonal trust was fully mediated by expectation of monetary profit. These findings demonstrate an effect of pain on interpersonal trust and suggest a reciprocity mechanism that the effect may be driven by self-interest rather than altruistic motivation. The pain effect on trust was evident only in females, implying distinct pain coping strategies used by both genders. The present work highlights the social component of pain and extends our understanding of mutual interactions between pain and social cognition. © 2017 European Pain Federation - EFIC®.

Evoked Pressure Pain Sensitivity Is Associated with Differential Analgesic Response to Verum and Sham Acupuncture in Fibromyalgia.

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Zucker, Noah A; Tsodikov, Alex; Mist, Scott D; Cina, Stephen; Napadow, Vitaly; Harris, Richard E

2017-08-01

Fibromyalgia is a chronic pain condition with few effective treatments. Many fibromyalgia patients seek acupuncture for analgesia; however, its efficacy is limited and not fully understood. This may be due to heterogeneous pathologies among participants in acupuncture clinical trials. We hypothesized that pressure pain tenderness would differentially classify treatment response to verum and sham acupuncture in fibromyalgia patients. Baseline pressure pain sensitivity at the thumbnail at baseline was used in linear mixed models as a modifier of differential treatment response to sham versus verum acupuncture. Similarly, needle-induced sensation was also analyzed to determine its differential effect of treatment on clinical pain. A cohort of 114 fibromyalgia patients received baseline pressure pain testing and were randomized to either verum (N = 59) or sham (N = 55) acupuncture. Participants received treatments from once a week to three times a week, increasing in three-week blocks for a total of 18 treatments. Clinical pain was measured on a 101-point visual analog scale, and needle sensation was measured by questionnaire throughout the trial. Participants who had higher pain pressure thresholds had greater reduction in clinical pain following verum acupuncture while participants who had lower pain pressure thresholds showed better analgesic response to sham acupuncture. Moreover, patients with lower pressure pain thresholds had exacerbated clinical pain following verum acupuncture. Similar relationships were observed for sensitivity to acupuncture needling. These findings suggest that acupuncture efficacy in fibromyalgia may be underestimated and a more personalized treatment for fibromyalgia may also be possible. © 2017 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Increased sensitivity to supra-threshold painful stimuli in patients with multiple functional somatic symptoms (MFS)

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Kuzminskyte, Ruta; Kupers, Ronny Clement Florent; Videbech, Poul

2010-01-01

threshold and pain tolerance levels in patients with MFS. Twenty-two patients with MFS and 27 age- and sex-matched healthy control subjects volunteered for this study. The subjects received innocuous and noxious thermal stimuli to the volar forearm by means of a Peltier contact heat probe. We assessed pain...... threshold and pain tolerance with an ascending staircase method. Anxiety levels and hemodynamic (blood pressure, pulse rate) and endocrine (cortisol and prolactin release) responses were measured before and after pain testing. We found no group differences for any of the physiological or self...

Laparoscopic Cholecystectomy for Gallbladder Calculosis in Fibromyalgia Patients: Impact on Musculoskeletal Pain, Somatic Hyperalgesia and Central Sensitization

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Costantini, Raffaele; Affaitati, Giannapia; Massimini, Francesca; Tana, Claudio; Innocenti, Paolo; Giamberardino, Maria Adele

2016-01-01

Fibromyalgia, a chronic syndrome of diffuse musculoskeletal pain and somatic hyperalgesia from central sensitization, is very often comorbid with visceral pain conditions. In fibromyalgia patients with gallbladder calculosis, this study assessed the short and long-term impact of laparoscopic cholecystectomy on fibromyalgia pain symptoms. Fibromyalgia pain (VAS scale) and pain thresholds in tender points and control areas (skin, subcutis and muscle) were evaluated 1week before (basis) and 1week, 1,3,6 and 12months after laparoscopic cholecystectomy in fibromyalgia patients with symptomatic calculosis (n = 31) vs calculosis patients without fibromyalgia (n. 26) and at comparable time points in fibromyalgia patients not undergoing cholecystectomy, with symptomatic (n = 27) and asymptomatic (n = 28) calculosis, and no calculosis (n = 30). At basis, fibromyalgia+symptomatic calculosis patients presented a significant linear correlation between the number of previously experienced biliary colics and fibromyalgia pain (direct) and muscle thresholds (inverse)(pfibromyalgia pain significantly increased and all thresholds significantly decreased at 1week and 1month (1-way ANOVA, pFibromyalgia pain and thresholds returned to preoperative values at 3months, then pain significantly decreased and thresholds significantly increased at 6 and 12months (pfibromyalgia patients undergoing cholecystectomy thresholds did not change; in all other fibromyalgia groups not undergoing cholecystectomy fibromyalgia pain and thresholds remained stable, except in fibromyalgia+symptomatic calculosis at 12months when pain significantly increased and muscle thresholds significantly decreased (pfibromyalgia symptoms and that laparoscopic cholecystectomy produces only a transitory worsening of these symptoms, largely compensated by the long-term improvement/desensitization due to gallbladder removal. This study provides new insights into the role of visceral pain comorbidities and the effects of

Sensitization of the nociceptive system in patients with low back pain and sickness absence: Disc degeneration disease or pain syndrome

DEFF Research Database (Denmark)

Jensen, Ole Kudsk; Nielsen, Claus Vinther; Stengaard-Pedersen, Kristian

SENSITIZATION OF THE NOCICEPTIVE SYSTEM IN PATIENTS WITH LOW BACK PAIN AND SICKNESS ABSENCE O.K. Jensen1, C.V. Nielsen2, K. Stengaard-Pedersen3 1The Spine Center, Department of Internal Medicine, Region Hospital Silkeborg, 2Department of Clinical Social Medicine, University of Aarhus, and 3...... characterized by sensitization of the nociceptive system. Purpose: To assess sensitization of the nociceptive system in low back pain (LBP) patients by means of TP examination and measure of Pressure Pain Threshold (PPT) on the thumb nails. To search for associations between the number of TPs and structural...... = 1.35, p = 0.017) and mental distress (anxiety) in men (OR = 1.39, p = 0.003). After adjustment for age and sex, a positive association between LBP score and DDS was found only in patients with less than six TPs (OR = 1.21 (1.0-1.47), p = 0.043). Low PPT on the thumb nails was associated with DDS...

Facilitated pronociceptive pain mechanisms in radiating back pain compared with localized back pain

DEFF Research Database (Denmark)

Vaegter, Henrik Bjarke; Palsson, Thorvaldur Skuli; Graven-Nielsen, Thomas

2017-01-01

Facilitated pain mechanisms and impaired pain inhibition are often found in chronic pain patients. This study compared clinical pain profiles, pain sensitivity, as well as pro-nociceptive and anti-nociceptive mechanisms in patients with localized low back pain (n=18), localized neck pain (n=17......), low back and radiating leg pain (n=18), or neck and radiating arm pain (n=17). It was hypothesized that patients with radiating pain had facilitated pain mechanisms and impaired pain inhibition compared with localized pain patients. Cuff algometry was performed on the non-painful lower leg to assess...... threshold (HPT) at the non-painful hand were also assessed. Clinical pain intensity, psychological distress, and disability were assessed with questionnaires. TSP was increased in patients with radiating back pain compared with localized back pain (Ppain or localized low...

The Effect of Topical Local Anesthetics on Thermal Pain Sensitivity in Patients with Irritable Bowel Syndrome

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Anthony Rodrigues

2012-01-01

Full Text Available Generalized hypersensitivity that extends into somatic areas is common in patients with irritable bowel syndrome (IBS. The sensitized state, particularly assessed by experimental methods, is known to persist even during remissions of clinical pain. It was hypothesized that disease-related nociceptive activity in the gut maintains a systemic-sensitized state. The present study evaluated responses to prolonged thermal stimuli maintained at constant temperature or constant pain intensity during stimulation. The effect of topically applied rectal lidocaine on heat sensitivity was also evaluated. The question is whether silencing potential intestinal neural activity (which may not always lead to a conscious pain experience with lidocaine attenuates sensitization of somatic areas. Tests were also performed where lidocaine was applied orally to control for systemic or placebo effects of the drug. The IBS subjects exhibited a greater sensitivity to somatic heat stimuli compared to controls; however, lidocaine had no discernible effect on sensitization in this sample of IBS patients, where most of the individuals did not have clinical pain on the day of testing.

Healthy volunteers can be phenotyped using cutaneous sensitization pain models

DEFF Research Database (Denmark)

Werner, Mads U; Petersen, Karin; Rowbotham, Michael C

2013-01-01

Human experimental pain models leading to development of secondary hyperalgesia are used to estimate efficacy of analgesics and antihyperalgesics. The ability to develop an area of secondary hyperalgesia varies substantially between subjects, but little is known about the agreement following repe...... repeated measurements. The aim of this study was to determine if the areas of secondary hyperalgesia were consistently robust to be useful for phenotyping subjects, based on their pattern of sensitization by the heat pain models.......Human experimental pain models leading to development of secondary hyperalgesia are used to estimate efficacy of analgesics and antihyperalgesics. The ability to develop an area of secondary hyperalgesia varies substantially between subjects, but little is known about the agreement following...

Pain sensitivity of children with Down syndrome and their siblings: quantitative sensory testing versus parental reports.

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Valkenburg, Abraham J; Tibboel, Dick; van Dijk, Monique

2015-11-01

The aim of this study was to compare thermal detection and pain thresholds in children with Down syndrome with those of their siblings. Sensory detection and pain thresholds were assessed in children with Down syndrome and their siblings using quantitative testing methods. Parental questionnaires addressing developmental age, pain coping, pain behaviour, and chronic pain were also utilized. Forty-two children with Down syndrome (mean age 12y 10mo) and 24 siblings (mean age 15y) participated in this observational study. The different sensory tests proved feasible in 13 to 29 (33-88%) of the children with Down syndrome. These children were less sensitive to cold and warmth than their siblings, but only when measured with a reaction time-dependent method, and not with a reaction time-independent method. Children with Down syndrome were more sensitive to heat pain, and only 6 (14%) of them were able to adequately self-report pain, compared with 22 (92%) of siblings (pChildren with Down syndrome will remain dependent on pain assessment by proxy, since self-reporting is not adequate. Parents believe that their children with Down syndrome are less sensitive to pain than their siblings, but this was not confirmed by quantitative sensory testing. © 2015 Mac Keith Press.

The rubber hand illusion increases heat pain threshold.

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Hegedüs, G; Darnai, G; Szolcsányi, T; Feldmann, Á; Janszky, J; Kállai, J

2014-09-01

Accumulating evidence shows that manipulations of cortical body representation, for example, by simply viewing one's own body, can relieve pain in healthy subjects. Despite the widespread use of the rubber hand illusion (RHI) as an effective experimental tool for the manipulation of bodily awareness, previous studies examining the analgesic effect of the RHI have produced conflicting results. We used noxious heat stimuli to induce finger pain in 29 healthy subjects, and we recorded the participants' pain thresholds and subjective pain ratings during the RHI and during the control conditions. Two control conditions were included in our experiment - a standard one with reduced illusion strength (asynchronous stroking control) and an additional one in which the participants viewed their own hand. Raw data showed that both the RHI and the vision of the own hand resulted in slightly higher pain thresholds than the asynchronous stroking control (illusion: 47.79 °C; own-hand: 47.99 °C; asynchronous: 47.52 °C). After logarithmic transformation to achieve normality, paired t-tests revealed that both increases in pain threshold were significant (illusion/asynchronous: p = 0.036; own-hand/asynchronous: p = 0.007). In contrast, there was no significant difference in pain threshold between the illusion and the own-hand conditions (p = 0.656). Pain rating scores were not log-normal, and Wilcoxon singed-rank tests found no significant differences in pain ratings between the study conditions. The RHI increases heat pain threshold and the analgesic effect of the RHI is comparable with that of seeing one's own hand. The latter finding may have clinical implications. © 2014 European Pain Federation - EFIC®

Effect of TENS on pain in relation to central sensitization in patients with osteoarthritis of the knee: study protocol of a randomized controlled trial

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Beckwée David

2012-02-01

Full Text Available Abstract Background Central sensitization has recently been documented in patients with knee osteoarthritis (OAk. So far, the presence of central sensitization has not been considered as a confounding factor in studies assessing the pain inhibitory effect of tens on osteoarthritis of the knee. The purpose of this study is to explore the pain inhibitory effect of burst tens in OAk patients and to explore the prognostic value of central sensitization on the pain inhibitory effect of tens in OAk patients. Methods Patients with knee pain due to OAk will be recruited through advertisements in local media. Temporal summation, before and after a heterotopic noxious conditioning stimulation, will be measured. In addition, pain on a numeric rating score, WOMAC subscores for pain and function and global perceived effect will be assessed. Patients will be randomly allocated to one of two treatment groups (tens, sham tens. Follow-up measurements will be scheduled after a period of 6 and 12 weeks. Discussion Tens influences pain through the electrical stimulation of low-threshold A-beta cutaneous fibers. The responsiveness of central pain-signaling neurons of centrally sensitized OAk patients may be augmented to the input of these electrical stimuli. This would encompass an adverse therapy effect of tens. To increase treatment effectiveness it might be interesting to identify a subgroup of symptomatic OAk patients, i.e., non-sensitized patients, who are likely to benefit from burst tens. Trial Registration ClinicalTrials.gov: NCT01390285

Negative body image associated with changes in the visual body appearance increases pain perception.

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Michihiro Osumi

Full Text Available Changing the visual body appearance by use of as virtual reality system, funny mirror, or binocular glasses has been reported to be helpful in rehabilitation of pain. However, there are interindividual differences in the analgesic effect of changing the visual body image. We hypothesized that a negative body image associated with changing the visual body appearance causes interindividual differences in the analgesic effect although the relationship between the visual body appearance and analgesic effect has not been clarified. We investigated whether a negative body image associated with changes in the visual body appearance increased pain. Twenty-five healthy individuals participated in this study. To evoke a negative body image, we applied the method of rubber hand illusion. We created an "injured rubber hand" to evoke unpleasantness associated with pain, a "hairy rubber hand" to evoke unpleasantness associated with embarrassment, and a "twisted rubber hand" to evoke unpleasantness associated with deviation from the concept of normality. We also created a "normal rubber hand" as a control. The pain threshold was measured while the participant observed the rubber hand using a device that measured pain caused by thermal stimuli. Body ownership experiences were elicited by observation of the injured rubber hand and hairy rubber hand as well as the normal rubber hand. Participants felt more unpleasantness by observing the injured rubber hand and hairy rubber hand than the normal rubber hand and twisted rubber hand (p<0.001. The pain threshold was lower under the injured rubber hand condition than with the other conditions (p<0.001. We conclude that a negative body appearance associated with pain can increase pain sensitivity.

Increased Evoked Potentials and Behavioral Indices in Response to Pain Among Individuals with Intellectual Disability.

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Benromano, Tali; Pick, Chaim G; Granovsky, Yelena; Defrin, Ruth

2017-09-01

Previous studies on the sensitivity and reactivity to pain of individuals with intellectual disability (ID) are inconsistent. The inconsistency may result from the reliance on self-reports and facial expressions of pain that are subject to internal and external biases. The aim was therefore to evaluate the reactivity to pain of individuals with ID by recording pain-evoked potentials (EPs), here for the first time, and testing their association with behavioral pain indices. Forty-one healthy adults, 16 with mild-moderate ID and 25 controls. Subjects received series of phasic heat stimuli and rated their pain on self-report scales. Changes in facial expressions and in pain EPs were recorded and analyzed offline. Pain self-reports, facial expressions, and the N2P2 amplitudes of the EPs exhibited stimulus-response relationship with stimulation intensity in both groups. The facial expressions and N2P2 amplitudes of individuals with ID were increased and N2P2 latency prolonged compared with controls. N2P2 amplitudes correlated with self-reports only in controls. Individuals with ID are hypersensitive/reactive to pain, a finding bearing clinical implications. Although pain EPs may reflect a somewhat different aspect of pain than the behavioral indices do, there is evidence to support their use to record pain in noncommunicative individuals, pending further validation. © 2017 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Noise Sensitivities in Dogs: An Exploration of Signs in Dogs with and without Musculoskeletal Pain Using Qualitative Content Analysis

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Ana Luisa Lopes Fagundes

2018-02-01

Full Text Available Noise sensitivity is a common behaviour problem in dogs. In humans, there is a well-established relationship between painful conditions and the development of fear-related avoidance responses. Whilst it is likely that a relationship exists between noise sensitivity and pain in dogs, this does not appear to have been investigated. The aim of this study was to explore the signs of noise sensitivity in dogs with and without musculoskeletal pain by comparing case histories using qualitative content analysis. Data were extracted from the clinical records of 20 cases of dogs presenting with noise sensitivity seen by clinical animal behaviourists at the University of Lincoln, composed of 2 groups—10 “clinical cases” with pain and 10 “control cases” without pain. Loud noises as a trigger of noise sensitivity were a common theme in both groups but ubiquitous among “clinical cases.” In “clinical cases” (i.e., those where pain was identified, the age of onset of the noise sensitivity was on average nearly 4 years later than “control cases.” In addition, strong themes emerged relating to widespread generalisation to associated environments and avoidance of other dogs in the “clinical cases,” which did not appear in the “control cases.” “Clinical cases” responded well to treatment once the involvement of pain had been identified. Veterinarians and behaviourists should carefully assess dogs with noise sensitivities for pain-related problems especially if presenting with these characteristics.

Noise Sensitivities in Dogs: An Exploration of Signs in Dogs with and without Musculoskeletal Pain Using Qualitative Content Analysis.

Science.gov (United States)

Lopes Fagundes, Ana Luisa; Hewison, Lynn; McPeake, Kevin J; Zulch, Helen; Mills, Daniel Simon

2018-01-01

Noise sensitivity is a common behaviour problem in dogs. In humans, there is a well-established relationship between painful conditions and the development of fear-related avoidance responses. Whilst it is likely that a relationship exists between noise sensitivity and pain in dogs, this does not appear to have been investigated. The aim of this study was to explore the signs of noise sensitivity in dogs with and without musculoskeletal pain by comparing case histories using qualitative content analysis. Data were extracted from the clinical records of 20 cases of dogs presenting with noise sensitivity seen by clinical animal behaviourists at the University of Lincoln, composed of 2 groups-10 "clinical cases" with pain and 10 "control cases" without pain. Loud noises as a trigger of noise sensitivity were a common theme in both groups but ubiquitous among "clinical cases." In "clinical cases" (i.e., those where pain was identified), the age of onset of the noise sensitivity was on average nearly 4 years later than "control cases." In addition, strong themes emerged relating to widespread generalisation to associated environments and avoidance of other dogs in the "clinical cases," which did not appear in the "control cases." "Clinical cases" responded well to treatment once the involvement of pain had been identified. Veterinarians and behaviourists should carefully assess dogs with noise sensitivities for pain-related problems especially if presenting with these characteristics.

Pain and chewing sensitivity during fixed orthodontic treatment in extraction and non-extraction patients.

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Sayar, Gulsilay

2017-01-01

The aim of this study was to evaluate the differences in pain perception and chewing sensitivity between extraction and non-extraction patients. Thirty orthodontic patients (11 males, 19 females) were included in this study who were classified as extraction (n=15; 6 males, 9 females) and non-extraction patients (n=15; 7 males, 8 females). The mean age of patients were 15.10±1.83 years in non-extraction group and 15.44±0.75 years in extraction group. The patients were asked to complete the Visual Analogue Scale (VAS) questionnaire and they were asked to mark the presence or absence of sensitivity during 7 days after the first arch wire placement. Pain intensity comparison between groups was performed using the Mann-Whitney U test. The Friedman test was used to analyze within-group differences over time. There were no significant differences in pain scores between the groups. Pain levels significantly decreased between day 1 and day 3 in both the groups. No differences were found in the chewing sensitivity between the non-extraction and extraction groups. No difference in the pain perception was observed between the extraction and non-extraction patients during the 7 days after arch wire placement.

PAIN AND CHEWING SENSITIVITY DURING FIXED ORTHODONTIC TREATMENT IN EXTRACTION AND NON-EXTRACTION PATIENTS

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Gülşilay SAYAR

2017-04-01

Full Text Available Purpose: The aim of this study was to evaluate the differences in pain perception and chewing sensitivity between extraction and non-extraction patients. Subjects and Methods: Thirty orthodontic patients (11 males, 19 females were included in this study who were classified as extraction (n=15; 6 males, 9 females and non-extraction patients (n=15; 7 males, 8 females. The mean age of patients were 15.10±1.83 years in non-extraction group and 15.44±0.75 years in extraction group. The patients were asked to complete the Visual Analogue Scale (VAS questionnaire and they were asked to mark the presence or absence of sensitivity during 7 days after the first arch wire placement. Pain intensity comparison between groups was performed using the Mann-Whitney U test. The Friedman test was used to analyze within-group differences over time. Results: There were no significant differences in pain scores between the groups. Pain levels significantly decreased between day 1 and day 3 in both the groups. No differences were found in the chewing sensitivity between the non-extraction and extraction groups. Conclusion: No difference in the pain perception was observed between the extraction and non-extraction patients during the 7 days after arch wire placement.

Heat pain detection threshold is associated with the area of secondary hyperalgesia following brief thermal sensitization

DEFF Research Database (Denmark)

Hansen, Morten Sejer; Wetterslev, Jørn; Pipper, Christian Bressen

2017-01-01

INTRODUCTION: The area of secondary hyperalgesia following brief thermal sensitization (BTS) of the skin and heat pain detection thresholds (HPDT) may both have predictive abilities in regards to pain sensitivity and clinical pain states. The association between HPDT and secondary hyperalgesia......, however, remains unsettled, and the dissimilarities in physiologic properties suggest that they may represent 2 distinctively different pain entities. The aim of this study was to investigate the association between HPDT and BTS-induced secondary hyperalgesia. METHODS: A sample of 121 healthy male...... participants was included and tested on 2 separate study days with BTS (45°C, 3 minutes), HPDT, and pain during thermal stimulation (45°C, 1 minute). Areas of secondary hyperalgesia were quantified after monofilament pinprick stimulation. The pain catastrophizing scale (PCS) and hospital anxiety and depression...

Co-occurrence of Pain Symptoms and Somatosensory Sensitivity in Burning Mouth Syndrome: A Systematic Review

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Moisset, Xavier; Calbacho, Valentina; Torres, Pilar; Gremeau-Richard, Christelle; Dallel, Radhouane

2016-01-01

Background Burning mouth syndrome (BMS) is a chronic and spontaneous oral pain with burning quality in the tongue or other oral mucosa without any identifiable oral lesion or laboratory finding. Pathogenesis and etiology of BMS are still unknown. However, BMS has been associated with other chronic pain syndromes including other idiopathic orofacial pain, the dynias group and the family of central sensitivity syndromes. This would imply that BMS shares common mechanisms with other cephalic and/or extracephalic chronic pains. The primary aim of this systematic review was to determine whether BMS is actually associated with other pain syndromes, and to analyze cephalic and extracephalic somatosensory sensitivity in these patients. Methods This report followed the PRISMA Statement. An electronic search was performed until January 2015 in PubMed, Cochrane library, Wiley and ScienceDirect. Searched terms included “burning mouth syndrome OR stomatodynia OR glossodynia OR burning tongue OR oral burning”. Studies were selected according to predefined inclusion criteria (report of an association between BMS and other pain(s) symptoms or of cutaneous cephalic and/or extracephalic quantitative sensory testing in BMS patients), and a descriptive analysis conducted. Results The search retrieved 1512 reports. Out of these, twelve articles met criteria for co-occurring pain symptoms and nine studies for quantitative sensory testing (QST) in BMS patients. The analysis reveals that in BMS patients co-occurring pain symptoms are rare, assessed by only 0.8% (12 of 1512) of the retrieved studies. BMS was associated with headaches, TMD, atypical facial pain, trigeminal neuralgia, post-herpetic facial pain, back pain, fibromyalgia, joint pain, abdominal pain, rectal pain or vulvodynia. However, the prevalence of pain symptoms in BMS patients is not different from that in the age-matched general population. QST studies reveal no or inconsistent evidence of abnormal cutaneous cephalic

Co-occurrence of Pain Symptoms and Somatosensory Sensitivity in Burning Mouth Syndrome: A Systematic Review.

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Xavier Moisset

Full Text Available Burning mouth syndrome (BMS is a chronic and spontaneous oral pain with burning quality in the tongue or other oral mucosa without any identifiable oral lesion or laboratory finding. Pathogenesis and etiology of BMS are still unknown. However, BMS has been associated with other chronic pain syndromes including other idiopathic orofacial pain, the dynias group and the family of central sensitivity syndromes. This would imply that BMS shares common mechanisms with other cephalic and/or extracephalic chronic pains. The primary aim of this systematic review was to determine whether BMS is actually associated with other pain syndromes, and to analyze cephalic and extracephalic somatosensory sensitivity in these patients.This report followed the PRISMA Statement. An electronic search was performed until January 2015 in PubMed, Cochrane library, Wiley and ScienceDirect. Searched terms included "burning mouth syndrome OR stomatodynia OR glossodynia OR burning tongue OR oral burning". Studies were selected according to predefined inclusion criteria (report of an association between BMS and other pain(s symptoms or of cutaneous cephalic and/or extracephalic quantitative sensory testing in BMS patients, and a descriptive analysis conducted.The search retrieved 1512 reports. Out of these, twelve articles met criteria for co-occurring pain symptoms and nine studies for quantitative sensory testing (QST in BMS patients. The analysis reveals that in BMS patients co-occurring pain symptoms are rare, assessed by only 0.8% (12 of 1512 of the retrieved studies. BMS was associated with headaches, TMD, atypical facial pain, trigeminal neuralgia, post-herpetic facial pain, back pain, fibromyalgia, joint pain, abdominal pain, rectal pain or vulvodynia. However, the prevalence of pain symptoms in BMS patients is not different from that in the age-matched general population. QST studies reveal no or inconsistent evidence of abnormal cutaneous cephalic and extracephalic

Optokinetic stimulation increases limb pain and forehead hyperalgesia in complex regional pain syndrome

DEFF Research Database (Denmark)

Knudsen, Lone F.; Drummond, Peter D.

2015-01-01

BACKGROUND: Ambiguous visual stimuli increase limb pain in patients with complex regional pain syndrome (CRPS), possibly due to afferent sensory feedback conflicts. Conflicting sensory stimuli can also generate unpleasant sensations in healthy people such as during motion sickness. We wanted to i...

Co-morbid pain and opioid addiction: long term effect of opioid maintenance on acute pain.

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Wachholtz, Amy; Gonzalez, Gerardo

2014-12-01

Medication assisted treatment for opioid dependence alters the pain experience. This study will evaluate changes pain sensitivity and tolerance with opioid treatments; and duration of this effect after treatment cessation. 120 Individuals with chronic pain were recruited in 4 groups (N = 30): 1-methadone for opioid addiction; 2-buprenorphine for opioid addiction; 3-history of opioid maintenance treatment for opioid addiction but with prolonged abstinence (M = 121 weeks; SD = 23.3); and 4-opioid naïve controls. Participants completed a psychological assessment and a cold water task including, time to first pain (sensitivity) and time to stopping the pain task (tolerance). Data analysis used survival analyses. A Kaplan-Meier-Cox survival analysis showed group differences for both pain sensitivity (log rank = 15.50; p opioid maintenance resulted in differing pain sensitivity compared to opioid naïve (p's opioid maintenance compared to active methadone patients (p opioid naïve control group participants (p's opioid abstinence increased (R = .37; p opioid maintenance, there appears to be long-term differences in pain sensitivity that do not resolve with discontinuation of opioid maintenance. Although pain sensitivity does not change, pain tolerance does improve after opioid maintenance cessation. Implications for treating co-morbid opioid addiction and pain (acute and chronic) are discussed. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Experimental knee pain evoke spreading hyperalgesia and facilitated temporal summation of pain

DEFF Research Database (Denmark)

Jørgensen, Tanja Schjødt; Henriksen, Marius; Danneskiold-Samsøe, Bente

2013-01-01

OBJECTIVES: This study evaluated the deep-tissue pressure pain sensitivity and temporal summation of pain within and around healthy knees exposed to experimental pain. DESIGN: The study was designed as a randomized crossover trial, with each subject tested on 1 day. SETTING: All tests were carried...... occasions: baseline, immediately after the injection, and when pain had vanished. Assessments sites were located in the peripatellar region, vastus lateralis, and tibialis anterior muscles. RESULTS: The experimental knee pain model demonstrated 1) hyperalgesia to pressure stimulation on the infrapatellar...... fat pad during experimental pain, and 2) facilitated temporal summation of pressure pain at the infrapatellar fat pad and knee-related muscles. CONCLUSION: The increased sensitivity and temporal summation found in this study were exclusive to deep -tissue with no contralateral decreased pain...

Nicotine withdrawal and stress-induced changes in pain sensitivity: a cross-sectional investigation between abstinent smokers and nonsmokers.

Science.gov (United States)

Nakajima, Motohiro; Al'Absi, Mustafa

2014-10-01

Chronic smoking has been linked with alterations in endogenous pain regulation. These alterations may be pronounced when individuals quit smoking because nicotine withdrawal produces a variety of psychological and physiological symptoms. Smokers interested in quitting (n = 98) and nonsmokers (n = 37) completed a laboratory session including cold pressor test (CPT) and heat thermal pain. Smokers set a quit date and completed the session after 48 h of abstinence. Participants completed the pain assessments once after rest and once after stress. Cardiovascular and nicotine withdrawal measures were collected. Smokers showed blunted cardiovascular responses to stress relative to nonsmokers. Only nonsmokers had greater pain tolerance to CPT after stress than after rest. Lower systolic blood pressure was related to lower pain tolerance. These findings suggest that smoking withdrawal is associated with blunted stress response and increased pain sensitivity. Copyright © 2014 Society for Psychophysiological Research.

Bilateral widespread mechanical pain hypersensitivity as sign of central sensitization in patients with cluster headache.

Science.gov (United States)

Fernández-de-Las-Peñas, César; Ortega-Santiago, Ricardo; Cuadrado, María L; López-de-Silanes, Carlos; Pareja, Juan A

2011-03-01

To investigate bilateral widespread pressure pain hyperalgesia in deep tissues over symptomatic (trigemino-cervical) and nonsymptomatic (distant pain-free) regions in patients with cluster headache (CH). Central sensitization is claimed to play a relevant role in CH. No study has previously searched for widespread pressure hyperalgesia in deep tissues over both symptomatic (trigemino-cervical) and nonsymptomatic (distant pain-free) regions in patients with CH. Sixteen men (mean age: 43 ± 11 years) with CH in a remission phase and 16 matched controls were recruited. Pressure pain thresholds (PPTs) were bilaterally measured over the supra-orbital (V1), infra-orbital (V2), mental (V3), median (C5), radial (C6), and ulnar (C7) nerves, C5-C6 zygapophyseal joint, mastoid process, and tibialis anterior muscle by an assessor blinded to the subjects' condition. The results showed that PPT levels were significantly decreased bilaterally in patients with CH as compared with healthy controls (all sites, P < .001). A greater degree of sensitization over the mastoid process (P < .001) and a lower degree of sensitization over the tibialis anterior muscle (P < .01) was found. Our findings revealed bilateral widespread pressure pain hypersensitivity in patients with CH confirming the presence of central sensitization mechanisms in this headache condition. © 2010 American Headache Society.

Association of Exercise Therapy and Reduction of Pain Sensitivity in Patients With Knee Osteoarthritis

DEFF Research Database (Denmark)

Henriksen, Marius; Klokker, Louise; Graven-Nielsen, Thomas

2014-01-01

OBJECTIVE: Exercise has beneficial effects on pain in knee osteoarthritis (OA), yet the underlying mechanisms are unclear. The purpose of this study was to investigate the effects of exercise on pressure-pain sensitivity in patients with knee OA. METHODS: In a randomized controlled trial...... visual analog scale pain scores during constant pressure for 6 minutes at 125% of the PPT as a measure of temporal summation (TS) of pressure-pain. Secondary outcomes included self-reported pain using the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire. Analyses were based on the "per...

No evidence for generalized increased postoperative responsiveness to pain: a combined behavioral and serial functional magnetic resonance imaging study

DEFF Research Database (Denmark)

Kupers, Ron; Schneider, Fabien C G; Christensen, Rune

2009-01-01

area and to the lower forearm, a site remote from the surgical area. A group of eight age- and sex-matched control subjects underwent the same two-test procedure except that they were not submitted to an orthopedic surgical intervention. RESULTS: Subjective pain and brain responses to innocuous...... and noxious stimulation were not increased postoperatively. Actually, responses in primary and secondary somatosensory cortex for stimulation of the operated leg were significantly smaller after surgery. Brain responses in the control group did not differ significantly across the two sessions. CONCLUSION......BACKGROUND: Although it is generally accepted that increased pain responsiveness and central sensitization develop after major tissue injury, this claim has not been tested using brain imaging methods in a clinical pain setting. We tested this hypothesis using a postoperative pain model...

Linkage between pain sensitivity and empathic response in adolescents with autism spectrum conditions and conduct disorder symptoms.

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Chen, Chenyi; Hung, An-Yi; Fan, Yang-Teng; Tan, Shuai; Hong, Hua; Cheng, Yawei

2017-02-01

Lack of empathy is one of the behavioral hallmarks in individuals with autism spectrum conditions (ASC) as well as youth with conduct disorder symptoms (CDS). Previous research has reliably documented considerable overlap between the perception of others' pain and first-hand experience of pain. However, the linkage between empathy for pain and sensitivity to physical pain needs to be empirically determined, particularly in individuals with empathy deficits. This study measured the pressure pain threshold, which indexes sensitization of peripheral nociceptors, and assessed subjective ratings of unpleasantness and pain intensity in response to empathy-eliciting stimuli depicting physical bodily injuries in three age- and sex-matched participant groups: ASC, CDS, and typically developing controls (TDC). The results indicated that the pain threshold was lowest in the ASC group and highest in the CDS group. The ASC group displayed lower ratings of unpleasantness and pain intensity than did the TDC and CDS groups. Within the ASC and CDS, pain intensity ratings were significantly correlated with unpleasantness ratings to others' pain. Moreover, the ASC significantly differed from the TDC in the correlation between pain threshold values and unpleasantness ratings. These findings may cast some light on the linkage between atypical low-level sensory functioning, for instance altered pain sensitivity, and high-level empathic processing. Autism Res 2017, 10: 267-275. © 2016 International Society for Autism Research, Wiley Periodicals, Inc. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.

Association between UGT2B7 gene polymorphisms and fentanyl sensitivity in patients undergoing painful orthognathic surgery

Science.gov (United States)

Muraoka, Wataru; Nishizawa, Daisuke; Fukuda, Kenichi; Kasai, Shinya; Hasegawa, Junko; Wajima, Koichi; Nakagawa, Taneaki

2016-01-01

Background Fentanyl is often used instead of morphine for the treatment of pain because it has fewer side effects. The metabolism of morphine by glucuronidation is known to be influenced by polymorphisms of the UGT2B7 gene. Some metabolic products of fentanyl are reportedly metabolized by glucuronate conjugation. The genes that are involved in the metabolic pathway of fentanyl may also influence fentanyl sensitivity. We analyzed associations between fentanyl sensitivity and polymorphisms of the UGT2B7 gene to clarify the hereditary determinants of individual differences in fentanyl sensitivity. Results This study examined whether single-nucleotide polymorphisms (SNPs) of the UGT2B7 gene affect cold pain sensitivity and the analgesic effects of fentanyl, evaluated by a standardized pain test and fentanyl requirements in healthy Japanese subjects who underwent uniform surgical procedures. The rs7439366 SNP of UGT2B7 is reportedly associated with the metabolism and analgesic effects of morphine. We found that this SNP is also associated with the analgesic effects of fentanyl in the cold pressor-induced pain test. It suggested that the C allele of the rs7439366 SNP may enhance analgesic efficacy. Two SNPs of UGT2B7, rs4587017 and rs1002849, were also found to be novel SNPs that may influence the analgesic effects of fentanyl in the cold pressor-induced pain test. Conclusions Fentanyl sensitivity for cold pressor-induced pain was associated with the rs7439366, rs4587017, and rs1002849 SNPs of the UGT2B7 gene. Our findings may provide valuable information for achieving satisfactory pain control and open to new avenues for personalized pain treatment. PMID:28256933

Music reduces pain and increases functional mobility in fibromyalgia

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Garza-Villarreal, Eduardo A.; Wilson, Andrew D.; Vase, Lene; Brattico, Elvira; Barrios, Fernando A.; Jensen, Troels S.; Romero-Romo, Juan I.; Vuust, Peter

2014-01-01

The pain in Fibromyalgia (FM) is difficult to treat and functional mobility seems to be an important comorbidity in these patients that could evolve into a disability. In this study we wanted to investigate the analgesic effects of music in FM pain. Twenty-two FM patients were passively exposed to (1) self-chosen, relaxing, pleasant music, and to (2) a control auditory condition (pink noise). They rated pain and performed the “timed-up & go task (TUG)” to measure functional mobility after each auditory condition. Listening to relaxing, pleasant, self-chosen music reduced pain and increased functional mobility significantly in our FM patients. The music-induced analgesia was significantly correlated with the TUG scores; thereby suggesting that the reduction in pain unpleasantness increased functional mobility. Notably, this mobility improvement was obtained with music played prior to the motor task (not during), therefore the effect cannot be explained merely by motor entrainment to a fast rhythm. Cognitive and emotional mechanisms seem to be central to music-induced analgesia. Our findings encourage the use of music as a treatment adjuvant to reduce chronic pain in FM and increase functional mobility thereby reducing the risk of disability. PMID:24575066

Contribution of microglia and astrocytes to the central sensitization, inflammatory and neuropathic pain in the juvenile rat

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Ikeda Hiroshi

2012-06-01

Full Text Available Abstract Background The development of pain after peripheral nerve and tissue injury involves not only neuronal pathways but also immune cells and glia. Central sensitization is thought to be a mechanism for such persistent pain, and ATP involves in the process. We examined the contribution of glia to neuronal excitation in the juvenile rat spinal dorsal horn which is subjected to neuropathic and inflammatory pain. Results In rats subjected to neuropathic pain, immunoreactivity for the microglial marker OX42 was markedly increased. In contrast, in rats subjected to inflammatory pain, immunoreactivity for the astrocyte marker glial fibrillary acidic protein was increased slightly. Optically-recorded neuronal excitation induced by single-pulse stimulation to the dorsal root was augmented in rats subjected to neuropathic and inflammatory pain compared to control rats. The bath application of a glial inhibitor minocycline and a p38 mitogen-activated protein kinase inhibitor SB203580 inhibited the neuronal excitation in rats subjected to neuropathic pain. A specific P2X1,2,3,4 antagonist TNP-ATP largely inhibited the neuronal excitation only in rats subjected to neuropathic pain rats. In contrast, an astroglial toxin L-alpha-aminoadipate, a gap junction blocker carbenoxolone and c-Jun N-terminal kinase inhibitor SP600125 inhibited the neuronal excitation only in rats subjected to inflammatory pain. A greater number of cells in spinal cord slices from rats subjected to neuropathic pain showed Ca2+ signaling in response to puff application of ATP. This Ca2+ signaling was inhibited by minocycline and TNP-ATP. Conclusions These results directly support the notion that microglia is more involved in neuropathic pain and astrocyte in inflammatory pain.

Intra-Articular Corticosteroids in Addition to Exercise for Reducing Pain Sensitivity in Knee Osteoarthritis

DEFF Research Database (Denmark)

Soriano-Maldonado, Alberto; Klokker, Louise; Bartholdy, Cecilie

2016-01-01

OBJECTIVE: To assess the effects of one intra-articular corticosteroid injection two weeks prior to an exercise-based intervention program for reducing pain sensitivity in patients with knee osteoarthritis (OA). DESIGN: Randomized, masked, parallel, placebo-controlled trial involving 100 particip......OBJECTIVE: To assess the effects of one intra-articular corticosteroid injection two weeks prior to an exercise-based intervention program for reducing pain sensitivity in patients with knee osteoarthritis (OA). DESIGN: Randomized, masked, parallel, placebo-controlled trial involving 100...... the injections all participants undertook a 12-week supervised exercise program. Main outcomes were changes from baseline in pressure-pain sensitivity (pressure-pain threshold [PPT] and temporal summation [TS]) assessed using cuff pressure algometry on the calf. These were exploratory outcomes from a randomized....... The mean group difference in changes from baseline at week 14 was 0.6 kPa (95% CI: -1.7 to 2.8; P = 0.626) for PPT and 384 mm×sec (95% CI: -2980 to 3750; P = 0.821) for TS. CONCLUSIONS: These results suggest that adding intra-articular corticosteroid injection 2 weeks prior to an exercise program does...

Pressure pain sensitivity maps, self-reported musculoskeletal disorders and sickness absence among cleaners

DEFF Research Database (Denmark)

Binderup, Asbjørn Thalund; Holtermann, Andreas; Søgaard, Karen

2011-01-01

back regions (27 points). LTSA was defined as ten or more consecutive workdays with sick leave. RESULTS: The PPT maps revealed the spatial heterogeneity in mechanical sensitivity among cleaners. The level of pain in the neck and dominant shoulder and upper back within the last 7 days correlated......BACKGROUND: Pressure pain threshold mapping is a valuable method for the identification of distinct zones of mechanical pain sensitivity. Such approach was applied for the first time in relation to self-reported musculoskeletal disorders and long-term sickness absence (LTSA) within the last 12...... months among cleaners. METHODS: About 29 cleaners filled out a self-administered questionnaire regarding health, work-related measures and musculoskeletal disorders. Subsequently, PPTs were measured at (1) tibialis anterior (control location, 1 point), (2) the neck-shoulder (48 points) and (3) the low...

The Discriminative validity of "nociceptive," "peripheral neuropathic," and "central sensitization" as mechanisms-based classifications of musculoskeletal pain.

LENUS (Irish Health Repository)

Smart, Keith M

2012-02-01

OBJECTIVES: Empirical evidence of discriminative validity is required to justify the use of mechanisms-based classifications of musculoskeletal pain in clinical practice. The purpose of this study was to evaluate the discriminative validity of mechanisms-based classifications of pain by identifying discriminatory clusters of clinical criteria predictive of "nociceptive," "peripheral neuropathic," and "central sensitization" pain in patients with low back (+\\/- leg) pain disorders. METHODS: This study was a cross-sectional, between-patients design using the extreme-groups method. Four hundred sixty-four patients with low back (+\\/- leg) pain were assessed using a standardized assessment protocol. After each assessment, patients\\' pain was assigned a mechanisms-based classification. Clinicians then completed a clinical criteria checklist indicating the presence\\/absence of various clinical criteria. RESULTS: Multivariate analyses using binary logistic regression with Bayesian model averaging identified a discriminative cluster of 7, 3, and 4 symptoms and signs predictive of a dominance of "nociceptive," "peripheral neuropathic," and "central sensitization" pain, respectively. Each cluster was found to have high levels of classification accuracy (sensitivity, specificity, positive\\/negative predictive values, positive\\/negative likelihood ratios). DISCUSSION: By identifying a discriminatory cluster of symptoms and signs predictive of "nociceptive," "peripheral neuropathic," and "central" pain, this study provides some preliminary discriminative validity evidence for mechanisms-based classifications of musculoskeletal pain. Classification system validation requires the accumulation of validity evidence before their use in clinical practice can be recommended. Further studies are required to evaluate the construct and criterion validity of mechanisms-based classifications of musculoskeletal pain.

Prevention and reversal of latent sensitization of dorsal horn neurons by glial blockers in a model of low back pain in male rats.

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Zhang, Juanjuan; Mense, Siegfried; Treede, Rolf-Detlef; Hoheisel, Ulrich

2017-10-01

In an animal model of nonspecific low back pain, recordings from dorsal horn neurons were made to investigate the influence of glial cells in the central sensitization process. To induce a latent sensitization of the neurons, nerve growth factor (NGF) was injected into the multifidus muscle; the manifest sensitization to a second NGF injection 5 days later was used as a read-out. The sensitization manifested in increased resting activity and in an increased proportion of neurons responding to stimulation of deep somatic tissues. To block microglial activation, minocycline was continuously administered intrathecally starting 1 day before or 2 days after the first NGF injection. The glia inhibitor fluorocitrate that also blocks astrocyte activation was administrated 2 days after the first injection. Minocycline applied before the first NGF injection reduced the manifest sensitization after the second NGF injection to control values. The proportion of neurons responsive to stimulation of deep tissues was reduced from 50% to 17.7% ( P pain model appears to depend on microglia activation, whereas its maintenance is regulated by activated astrocytes. NEW & NOTEWORTHY Activated microglia and astrocytes mediate the latent sensitization induced by nerve growth factor in dorsal horn neurons that receive input from deep tissues of the low back. These processes may contribute to nonspecific low back pain. Copyright © 2017 the American Physiological Society.

Central Sensitization and Neuropathic Features of Ongoing Pain in a Rat Model of Advanced Osteoarthritis.

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Havelin, Joshua; Imbert, Ian; Cormier, Jennifer; Allen, Joshua; Porreca, Frank; King, Tamara

2016-03-01

Osteoarthritis (OA) pain is most commonly characterized by movement-triggered joint pain. However, in advanced disease, OA pain becomes persistent, ongoing and resistant to treatment with nonsteroidal anti-inflammatory drugs (NSAIDs). The mechanisms underlying ongoing pain in advanced OA are poorly understood. We recently showed that intra-articular (i.a.) injection of monosodium iodoacetate (MIA) into the rat knee joint produces concentration-dependent outcomes. Thus, a low dose of i.a. MIA produces NSAID-sensitive weight asymmetry without evidence of ongoing pain and a high i.a. MIA dose produces weight asymmetry and NSAID-resistant ongoing pain. In the present study, palpation of the ipsilateral hind limb of rats treated 14 days previously with high, but not low, doses of i.a. MIA produced expression of the early oncogene, FOS, in the spinal dorsal horn. Inactivation of descending pain facilitatory pathways using a microinjection of lidocaine within the rostral ventromedial medulla induced conditioned place preference selectively in rats treated with the high dose of MIA. Conditioned place preference to intra-articular lidocaine was blocked by pretreatment with duloxetine (30 mg/kg, intraperitoneally at -30 minutes). These observations are consistent with the likelihood of a neuropathic component of OA that elicits ongoing, NSAID-resistant pain and central sensitization that is mediated, in part, by descending modulatory mechanisms. This model provides a basis for exploration of underlying mechanisms promoting neuropathic components of OA pain and for the identification of mechanisms that might guide drug discovery for treatment of advanced OA pain without the need for joint replacement. Difficulty in managing advanced OA pain often results in joint replacement therapy in these patients. Improved understanding of mechanisms driving NSAID-resistant ongoing OA pain might facilitate development of alternatives to joint replacement therapy. Our findings suggest

Music reduces pain and increases functional mobility in fibromyalgia

DEFF Research Database (Denmark)

Garza-Villarreal, Eduardo A.; Wilson, Andrew D; Vase, Lene

2014-01-01

task (not during), therefore the effect cannot be explained merely by motor entrainment to a fast rhythm. Cognitive and emotional mechanisms seem to be central to music-induced analgesia. Our findings encourage the use of music as a treatment adjuvant to reduce chronic pain in FM and increase......The pain in Fibromyalgia (FM) is difficult to treat and functional mobility seems to be an important comorbidity in these patients that could evolve into a disability. In this study we wanted to investigate the analgesic effects of music in FM pain. Twenty-two FM patients were passively exposed...... to (1) self-chosen, relaxing, pleasant music, and to (2) a control auditory condition (pink noise). They rated pain and performed the “timed-up & go task (TUG)” to measure functional mobility after each auditory condition. Listening to relaxing, pleasant, self-chosen music reduced pain and increased...

High frequency migraine is associated with lower acute pain sensitivity and abnormal insula activity related to migraine pain intensity, attack frequency, and pain catastrophizing

Directory of Open Access Journals (Sweden)

Vani A Mathur

2016-09-01

Full Text Available Migraine is a pain disorder associated with abnormal brain structure and function, yet the effect of migraine on acute pain processing remains unclear. It also remains unclear whether altered pain-related brain responses and related structural changes are associated with clinical migraine characteristics. Using fMRI and three levels of thermal stimuli (non-painful, mildly painful, and moderately painful, we compared whole-brain activity between 14 migraine patients and 14 matched controls. Although, there were no significant differences in pain thresholds and pre-scan pain ratings to mildly painful thermal stimuli, patients had aberrant suprathreshold nociceptive processing. Compared to controls, patients had reduced activity in pain modulatory regions including left dorsolateral prefrontal, posterior parietal, and middle temporal cortices and, at a lower-threshold, greater activation in the right mid-insula to moderate pain versus mild pain. We also found that pain-related activity in the insula was associated with clinical variables in patients, including associations between: bilateral anterior insula and pain catastrophizing (PCS; bilateral anterior insula and contralateral posterior insula and migraine pain intensity; and bilateral posterior insula and migraine frequency at a lower-threshold. PCS and migraine pain intensity were also negatively associated with activity in midline regions including posterior cingulate and medial prefrontal cortices. Diffusion tensor imaging revealed a negative correlation between fractional anisotropy (a measure of white matter integrity; FA and migraine duration in the right mid-insula and a positive correlation between left mid-insula FA and PCS. In sum, while patients showed lower sensitivity to acute noxious stimuli, the neuroimaging findings suggest enhanced nociceptive processing and significantly disrupted modulatory networks, particularly involving the insula cortex, associated with indices of

Sensitivity and Specificity of the Comfort Scale to Assess Pain in Ventilated Critically Ill Adult Patients in Intensive Care Unit

OpenAIRE

Wahyuningsih, Indah Sri; Prasetyo, Awal; Utami, Reni Sulung

2017-01-01

Background: Pain is a common phenomenon experienced by ventilated and critically ill adult patients. It is urgent to measure the pain among these patients since they are unable to report their pain verbally. Comfort Scale is one of the instruments used to measure pain in adult patients. The scale is used to measure pain among children patients with fairly high sensitivity and specificity.Purpose: This study aimed to examine the sensitivity and specificity of the Comfort Scale to measure pain ...

Role of capsaicin- and heat-sensitive afferents in stimulation of acupoint-induced pain and analgesia in humans.

Science.gov (United States)

Lei, Jing; Ye, Gang; Wu, Jiang-Tao; Pertovaara, Antti; You, Hao-Jun

2017-09-01

We investigated role of capsaicin-sensitive afferents within and without the areas of Zusanli (ST36)/Shangjuxu (ST37) acupoints along the stomach (ST) meridian in the perception and modulation of pain assessed by visual analog scale of pain and its distribution rated by subjects, pressure pain threshold (PPT), and heat pain threshold (HPT) in humans. Compared with the treatment of non-acupoint area, capsaicin (100µg/50µl) administered into either ST36 or ST37 acupoint caused the strongest pain intensity and the most extensive pain distribution, followed by rapid onset, bilateral, long-lasting secondary mechanical hyperalgesia and slower onset secondary heat hypoalgesia (1day after the capsaicin treatment). Between treatments of different acupoints, capsaicin administrated into the ST36 acupoint exhibited the stronger pain intensity and more widespread pain distribution compared with the treatment of ST37 acupoint. A period of 30- to 45-min, but not 15-min, 43°C heating-needle stimulation applied to the ST36 acupoint significantly enhanced the HPT, and had no effect on PPT. Upon trapezius muscle pain elicited by the i.m. injection of 5.8% saline, pre-emptive treatment of the contralateral ST36 acupoint with 43°C heating-needle stimulation alleviated the ongoing muscle pain, reduced painful area, and reversed the decrease in HPT. It is suggested that (1) pain elicited from the acupoint and non-acupoint areas differs significantly, which are supposed to be dependent on the different distributions and contributions of capsaicin-sensitive afferents. (2) Non-painful heat stimulation is a valid approach in prevention of ongoing muscle pain with associated post-effects of peripheral and central sensitization. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

Pain-related anxiety influences pain perception differently in men and women: a quantitative sensory test across thermal pain modalities.

Science.gov (United States)

Thibodeau, Michel A; Welch, Patrick G; Katz, Joel; Asmundson, Gordon J G

2013-03-01

The sexes differ with respect to perception of experimental pain. Anxiety influences pain perception more in men than in women; however, there lacks research exploring which anxiety constructs influence pain perception differentially between men and women. Furthermore, research examining whether depression is associated with pain perception differently between the sexes remains scant. The present investigation was designed to examine how trait anxiety, pain-related anxiety constructs (ie, fear of pain, pain-related anxiety, anxiety sensitivity), and depression are associated with pain perception between the sexes. A total of 95 nonclinical participants (55% women) completed measures assessing the constructs of interest and participated in quantitative sensory testing using heat and cold stimuli administered by a Medoc Pathway Pain and Sensory Evaluation System. The findings suggest that pain-related anxiety constructs, but not trait anxiety, are associated with pain perception. Furthermore, these constructs are associated with pain intensity ratings in men and pain tolerance levels in women. This contrasts with previous research suggesting that anxiety influences pain perception mostly or uniquely in men. Depression was not systematically associated with pain perception in either sex. Systematic relationships were not identified that allow conclusions regarding how fear of pain, pain-related anxiety, and anxiety sensitivity may contribute to pain perception differentially in men and women; however, anxiety sensitivity was associated with increased pain tolerance, a novel finding needing further examination. The results provide directions for future research and clinical endeavors and support that fear and anxiety are important features associated with hyperalgesia in both men and women. Copyright © 2012 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Handling Ibuprofen increases pain tolerance and decreases perceived pain intensity in a cold pressor test.

Directory of Open Access Journals (Sweden)

Abraham M Rutchick

Full Text Available Pain contributes to health care costs, missed work and school, and lower quality of life. Extant research on psychological interventions for pain has focused primarily on developing skills that individuals can apply to manage their pain. Rather than examining internal factors that influence pain tolerance (e.g., pain management skills, the current work examines factors external to an individual that can increase pain tolerance. Specifically, the current study examined the nonconscious influence of exposure to meaningful objects on the perception of pain. Participants (N = 54 completed a cold pressor test, examined either ibuprofen or a control object, then completed another cold pressor test. In the second test, participants who previously examined ibuprofen reported experiencing less intense pain and tolerated immersion longer (relative to baseline than those who examined the control object. Theoretical and applied implications of these findings are discussed.

Relationship Between ABCB1 Polymorphisms and Cold Pain Sensitivity Among Healthy Opioid-naive Malay Males.

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Zahari, Zalina; Lee, Chee Siong; Ibrahim, Muslih Abdulkarim; Musa, Nurfadhlina; Mohd Yasin, Mohd Azhar; Lee, Yeong Yeh; Tan, Soo Choon; Mohamad, Nasir; Ismail, Rusli

2017-09-01

Endogenous and exogenous opioids are substrates of the permeability glycoprotein (P-gp) efflux transporter, which is encoded by the ABCB1 (MDR1) gene. Genetic polymorphisms of ABCB1 may contribute to interindividual differences in pain modulation and analgesic responses. We investigated the relationship between ABCB1 polymorphisms and cold pain sensitivity among healthy males. Cold pain responses, including pain threshold and pain tolerance, were measured using the cold-pressor test (CPT). DNA was extracted from whole blood and genotyped for ABCB1 polymorphisms, including c.1236C>T (rs1128503), c.2677G>T/A (rs2032582), and c.3435C>T (rs1045642), using the allelic discrimination real-time polymerase chain reaction. A total of 152 participants were recruited in this observational study. Frequencies of mutated allele for c.1236C>T, c.2677G>T/A, and c.3435C>T polymorphisms were 56.6%, 49.7%, and 43.4%, respectively. Our results revealed an association of the CGC/CGC diplotype (c.1236C>T, c.2677G>T/A, and c.3435C>T) with cold pain sensitivity. Participants with the CGC/CGC diplotype had 90% and 72% higher cold pain thresholds (87.62 seconds vs. 46.19 seconds, P = 0.010) and cold pain tolerances (97.24 seconds vs. 56.54 seconds, P = 0.021), respectively, when compared with those without the diplotype. The CGC/CGC diplotype of ABCB1 polymorphisms was associated with variability in cold pain threshold and pain tolerance in healthy males. © 2016 World Institute of Pain.

Modulation of vagal tone enhances gastroduodenal motility and reduces somatic pain sensitivity

DEFF Research Database (Denmark)

Frøkjaer, J B; Bergmann, S; Brock, C

2016-01-01

algometry, conditioned pain modulation using a cold pressor test and a liquid meal ultrasonographic gastroduodenal motility test were performed. KEY RESULTS: Cardiac vagal tone increased during active treatment with t-VNS and DSB compared to sham (p = 0.009). In comparison to sham, thresholds to bone pain...... increased (p = 0.001), frequency of antral contractions increased (p = 0.004) and gastroduodenal motility index increased (p = 0.016) with active treatment. However, no effect on muscle pain thresholds and conditioned pain modulation was seen. CONCLUSIONS & INFERENCES: This experimental study suggests...

Dissatisfaction with own body makes patients with eating disorders more sensitive to pain

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Yamamotova, Anna; Bulant, Josef; Bocek, Vaclav; Papezova, Hana

2017-01-01

Body image represents a multidimensional concept including body image evaluation and perception of body appearance. Disturbances of body image perception are considered to be one of the central aspects of anorexia nervosa and bulimia nervosa. There is growing evidence that body image distortion can be associated with changes in pain perception. The aim of our study was to examine the associations between body image perception, body dissatisfaction, and nociception in women with eating disorders and age-matched healthy control women. We measured body dissatisfaction and pain sensitivity in 61 patients with Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition diagnoses of eating disorders (31 anorexia nervosa and 30 bulimia nervosa) and in 30 healthy women. Thermal pain threshold latencies were evaluated using an analgesia meter and body image perception and body dissatisfaction were assessed using Anamorphic Micro software (digital pictures of their own body distorted into larger-body and thinner-body images). Patients with eating disorders overestimated their body size in comparison with healthy controls, but the two groups did not differ in body dissatisfaction. In anorexia and bulimia patient groups, body dissatisfaction (calculated in pixels as desired size/true image size) correlated with pain threshold latencies (r=0.55, p=0.001), while between body image perception (determined as estimation size/true image size) and pain threshold, no correlation was found. Thus, we demonstrated that in patients with eating disorders, pain perception is significantly associated with emotional contrary to sensory (visual) processing of one’s own body image. The more the patients desired to be thin, the more pain-sensitive they were. Our findings based on some shared mechanisms of body dissatisfaction and pain perception support the significance of negative emotions specific for eating disorders and contribute to better understanding of the psychosomatic

APP/SOD1 overexpressing mice present reduced neuropathic pain sensitivity.

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Kotulska, Katarzyna; Larysz-Brysz, Magdalena; LePecheur, Marie; Marcol, Wiesław; Olakowska, Edyta; Lewin-Kowalik, Joanna; London, Jacqueline

2011-07-15

There are controversies regarding pain expression in mentally disabled people, including Down syndrome patients. The aim of this study was to examine neuropathic pain-related behavior and peripheral nerve regeneration in mouse model of Down syndrome. Sciatic nerves of double transgenic mice, overexpressing both amyloid precursor protein (APP) and Cu/Zn superoxide dismutase (SOD1) genes, and FVB/N wild type mice were transected and immediately resutured. Evaluation of autotomy and functional recovery was carried out during 4-week follow-up. We found markedly less severe autotomy in transgenic animals, although the onset of autotomy was significantly delayed in control mice. Interestingly, neuroma formation at the injury site was significantly more prominent in transgenic animals. Sciatic function index outcome was better in transgenic mice than in wild-type group. Histological evaluation revealed no statistically significant differences in the number of GAP-43-positive growth cones and macrophages in the distal stump of the transected nerve between groups. However, in transgenic animals, the regenerating axons were arranged more chaotically. The number of Schwann cells in the distal stump of the transected nerves was significantly lower in transgenic mice. The number of surviving motoneurons was markedly decreased in transgenic group. We measured also the atrophy of denervated muscles and found it decreased in APP/SOD1 overexpressing mice. Taken together, in this model of Down syndrome, we observed increased neuroma formation and decreased autotomy after peripheral nerve injury. Our findings suggest that APP/SOD1 overexpressing mice are less sensitive for neuropathic pain associated with neuroma. Copyright © 2011 Elsevier Inc. All rights reserved.

Bilateral widespread mechanical pain sensitivity in carpal tunnel syndrome: evidence of central processing in unilateral neuropathy.

Science.gov (United States)

Fernández-de-las-Peñas, César; de la Llave-Rincón, Ana Isabel; Fernández-Carnero, Josué; Cuadrado, María Luz; Arendt-Nielsen, Lars; Pareja, Juan A

2009-06-01

The aim of this study was to investigate whether bilateral widespread pressure hypersensitivity exists in patients with unilateral carpal tunnel syndrome. A total of 20 females with carpal tunnel syndrome (aged 22-60 years), and 20 healthy matched females (aged 21-60 years old) were recruited. Pressure pain thresholds were assessed bilaterally over median, ulnar, and radial nerve trunks, the C5-C6 zygapophyseal joint, the carpal tunnel and the tibialis anterior muscle in a blinded design. The results showed that pressure pain threshold levels were significantly decreased bilaterally over the median, ulnar, and radial nerve trunks, the carpal tunnel, the C5-C6 zygapophyseal joint, and the tibialis anterior muscle in patients with unilateral carpal tunnel syndrome as compared to healthy controls (all, P < 0.001). Pressure pain threshold was negatively correlated to both hand pain intensity and duration of symptoms (all, P < 0.001). Our findings revealed bilateral widespread pressure hypersensitivity in subjects with carpal tunnel syndrome, which suggest that widespread central sensitization is involved in patients with unilateral carpal tunnel syndrome. The generalized decrease in pressure pain thresholds associated with pain intensity and duration of symptoms supports a role of the peripheral drive to initiate and maintain central sensitization. Nevertheless, both central and peripheral sensitization mechanisms are probably involved at the same time in carpal tunnel syndrome.

Clinical descriptors for the recognition of central sensitization pain in patients with knee osteoarthritis

DEFF Research Database (Denmark)

Lluch, Enrique; Nijs, Jo; Courtney, Carol A

2018-01-01

BACKGROUND: Despite growing awareness of the contribution of central pain mechanisms to knee osteoarthritis pain in a subgroup of patients, routine evaluation of central sensitization is yet to be incorporated into clinical practice. AIM: The objective of this perspective is to design a set...... of clinical descriptors for the recognition of central sensitization in patients with knee osteoarthritis that can be implemented in clinical practice. METHODS: A narrative review of original research papers was conducted by nine clinicians and researchers from seven different countries to reach agreement...... hyperalgesia, hypoesthesia and reduced vibration sense. CONCLUSIONS: This article describes a set of clinically relevant descriptors that might indicate the presence of central sensitization in patients with knee osteoarthritis in clinical practice. Although based on research data, the descriptors proposed...

Women with dysmenorrhoea are hypersensitive to experimentally induced forearm ischaemia during painful menstruation and during the pain-free follicular phase.

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Iacovides, S; Avidon, I; Baker, F C

2015-07-01

Monthly primary dysmenorrhoeic pain is associated with increased sensitivity to painful stimuli, particularly in deep tissue. We investigated whether women with dysmenorrhoea, compared with controls, have increased sensitivity to experimentally induced deep-tissue muscle ischaemia in a body area distant from that of referred menstrual pain. The sub-maximal effort tourniquet test was used to induce forearm ischaemia in 11 women with severe dysmenorrhoea and in nine control women both during menstruation and in the follicular phase of the menstrual cycle. Von Frey hair assessments confirmed the presence of experimental ischaemia. Women rated the intensity of menstrual and ischaemic pain on a 100-mm visual analogue scale. Women with dysmenorrhoea [mean (SD): 68 (20) mm] reported significantly greater menstrual pain compared with controls [mean (SD): 2 (6) mm; p = 0.0001] during the menstruation phase. They also rated their forearm ischaemic pain as significantly greater than the controls during the menstruation [dysmenorrhoeics vs. controls mean (SD): 58 (19) mm vs. 31 (21) mm, p menstruation phase and pain-free follicular phase. These findings suggest the presence of long-lasting changes in muscle pain sensitivity in women with dysmenorrhoea. Our findings that dysmenorrhoeic women are hyperalgesic to a clinically relevant, deep-muscle ischaemic pain in areas outside of referred menstrual pain confirm other studies showing long-lasting changes in pain sensitivity outside of the painful period during menstruation. © 2014 European Pain Federation - EFIC®

Autism Spectrum Disorder and Amplified Pain.

LENUS (Irish Health Repository)

Clarke, Ciaran

2015-05-01

Among the core features of ASD, altered sensitivities in all modalities have been accorded increasing importance. Heightened sensitivity to pain and unusual expressions of and reaction to pain have not hitherto been widely recognised as a presenting feature of ASD in general paediatrics. Failure to recognise ASD as a common cause of pain can lead to late diagnosis, inappropriate treatment, distress, and further disability. Two cases are presented which illustrate the late presentation of Autism Spectrum Disorder (Asperger\\'s Syndrome subtype) with chronic unusual pain. Conclusion. Pain in autism can be atypical in its experience and expression and for this reason may go unrecognised by physicians treating chronic pain disorders.

Acute Responses of Strength and Running Mechanics to Increasing and Decreasing Pain in Patients With Patellofemoral Pain

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Bazett-Jones, David M.; Huddleston, Wendy; Cobb, Stephen; O'Connor, Kristian; Earl-Boehm, Jennifer E.

2017-01-01

Context:  Patellofemoral pain (PFP) is typically exacerbated by repetitive activities that load the patellofemoral joint, such as running. Understanding the mediating effects of changes in pain in individuals with PFP might inform injury progression, rehabilitation, or both. Objective:  To investigate the effects of changing pain on muscular strength and running biomechanics in those with PFP. Design:  Crossover study. Setting:  University research laboratory. Patients or Other Participants:  Seventeen participants (10 men, 7 women) with PFP. Intervention(s):  Each participant completed knee pain-reducing and pain-inducing protocols in random order. The pain-reducing protocol consisted of 15 minutes of transcutaneous electric nerve stimulation (TENS) around the patella. The pain-inducing protocol was sets of 20 repeated single-legged squats (RSLS). Participants completed RSLS sets until either their pain was within at least 1 cm of their pain during an exhaustive run or they reached 10 sets. Main Outcome Measure(s):  Pain, isometric hip and trunk strength, and running mechanics were assessed before and after the protocols. Dependent variables were pain, normalized strength (abduction, extension, external rotation, lateral trunk flexion), and peak lower extremity kinematics and kinetics in all planes. Pain scores were analyzed using a Friedman test. Strength and mechanical variables were analyzed using repeated-measures analyses of variance. The α level was set at P < .05. Results:  Pain was decreased after the TENS (pretest: 3.10 ± 1.95, posttest: 1.89 ± 2.33) and increased after the RSLS (baseline: 3.10 ± 1.95, posttest: 4.38 ± 2.40) protocols (each P < .05). The RSLS protocol resulted in a decrease in hip-extension strength (baseline: 0.355 ± 0.08 kg/kg, posttest: 0.309 ± 0.09 kg/kg; P < .001). Peak plantar-flexion angle was decreased after RSLS (baseline: −13.97° ± 6.41°, posttest: −12.84° ± 6.45°; P = .003). Peak hip

Cohort Removal Induces Changes in Body Temperature, Pain Sensitivity, and Anxiety-Like Behavior

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Takao, Keizo; Shoji, Hirotaka; Hattori, Satoko; Miyakawa, Tsuyoshi

2016-01-01

Mouse behavior is analyzed to elucidate the effects of various experimental manipulations, including gene mutation and drug administration. When the effect of a factor of interest is assessed, other factors, such as age, sex, temperature, apparatus, and housing, are controlled in experiments by matching, counterbalancing, and/or randomizing. One such factor that has not attracted much attention is the effect of sequential removal of animals from a common cage (cohort removal). Here we evaluated the effects of cohort removal on rectal temperature, pain sensitivity, and anxiety-like behavior by analyzing the combined data of a large number of C57BL/6J mice that we collected using a comprehensive behavioral test battery. Rectal temperature increased in a stepwise manner according to the position of sequential removal from the cage, consistent with previous reports. In the hot plate test, the mice that were removed first from the cage had a significantly longer latency to show the first paw response than the mice removed later. In the elevated plus maze, the mice removed first spent significantly less time on the open arms compared to the mice removed later. The results of the present study demonstrated that cohort removal induces changes in body temperature, pain sensitivity, and anxiety-like behavior in mice. Cohort removal also increased the plasma corticosterone concentration in mice. Thus, the ordinal position in the sequence of removal from the cage should be carefully counterbalanced between groups when the effect of experimental manipulations, including gene manipulation and drug administration, are examined using behavioral tests. PMID:27375443

Cohort removal induces changes in body temperature, pain sensitivity, and anxiety-like behavior

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Keizo eTakao

2016-06-01

Full Text Available Mouse behavior is analyzed to elucidate the effects of various experimental manipulations, including gene mutation and drug administration. When the effect of a factor of interest is assessed, other factors, such as age, sex, temperature, apparatus, and housing, are controlled in experiments by matching, counterbalancing, and/or randomizing. One such factor that has not attracted much attention is the effect of sequential removal of animals from a common cage (cohort removal. Here we evaluated the effects of cohort removal on rectal temperature, pain sensitivity, and anxiety-like behavior by analyzing the combined data of a large number of C57BL/6J mice that we collected using a comprehensive behavioral test battery. Rectal temperature increased in a stepwise manner according to the position of sequential removal from the cage, consistent with previous reports. In the hot plate test, the mice that were removed first from the cage had a significantly longer latency to show the first paw response than the mice removed later. In the elevated plus maze, the mice removed first spent significantly less time on the open arms compared to the mice removed later. The results of the present study demonstrated that cohort removal induces changes in body temperature, pain sensitivity, and anxiety-like behavior in mice. Cohort removal also increased the plasma corticosterone concentration in mice. Thus, the ordinal position in the sequence of removal from the cage should be carefully counterbalanced between groups when the effect of experimental manipulations, including gene manipulation and drug administration, are examined using behavioral tests.

Freezing of enkephalinergic functions by multiple noxious foci: a source of pain sensitization?

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François Cesselin

Full Text Available BACKGROUND: The functional significance of proenkephalin systems in processing pain remains an open question and indeed is puzzling. For example, a noxious mechanical stimulus does not alter the release of Met-enkephalin-like material (MELM from segments of the spinal cord related to the stimulated area of the body, but does increase its release from other segments. METHODOLOGY/PRINCIPAL FINDINGS: Here we show that, in the rat, a noxious mechanical stimulus applied to either the right or the left hind paw elicits a marked increase of MELM release during perifusion of either the whole spinal cord or the cervico-trigeminal area. However, these stimulatory effects were not additive and indeed, disappeared completely when the right and left paws were stimulated simultaneously. CONCLUSION/SIGNIFICANCE: We have concluded that in addition to the concept of a diffuse control of the transmission of nociceptive signals through the dorsal horn, there is a diffuse control of the modulation of this transmission. The "freezing" of Met-enkephalinergic functions represents a potential source of central sensitization in the spinal cord, notably in clinical situations involving multiple painful foci, e.g. cancer with metastases, poly-traumatism or rheumatoid arthritis.

Association between Pressure Pain Sensitivity, Performance stability and Overall Performance in Olympic Sailors

DEFF Research Database (Denmark)

Faber, Jens Oscar; Ballegaard, Søren

2016-01-01

Background: During sports competitions, the performance of athletes may be negatively affected by persistent stress and autonomic nervous system (ANS) dysfunction, both of which can be assessed by pressure pain sensitivity (PPS) at the chest bone. Objectives: To test the association between PPS......: r > 0.70; p stress and ANS dysfunction as assessed by PPS on one side and performance stability and overall performance on the other side. Keywords Autonomic nervous system dysfunction; Pressure pain sensitivity; Sports...... guide for persistent stress and ANS dysfunction. Performance stability, overall performance and PPS measure were assessed at three intervals. Results: At baseline, the median PPS was 83, the performance stability was inferior to the mean top 10 competitors, and the overall performance was rank eight...

Alexithymic trait, painful heat stimulation and everyday pain experience

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Olga ePollatos

2015-10-01

Full Text Available Background: Alexithymia was found to be associated with a variety of somatic complaints including somatoform pain symptoms. This study addressed the question of whether the different facets of alexithymia are related to responses in heat pain stimulation and its interrelations with levels of everyday pain as assessed by self report. Methods: In the study, sensitivity to heat pain was assessed in fifty healthy female participants. Alexithymia facets were assessed by the Toronto Alexithymia Scale. Pain threshold and tolerance were determined using a testing the limits procedure. Participants furthermore rated subjective intensities and unpleasantness of tonic heat stimuli (45.5 C to 47.5 C on visual analogue scales and on a questionnaire. Possible confounding with temperature sensitivity and mood was controlled. Everyday pain was assessed by self-report addressing everyday pain frequency, intensity and impairment experienced over the last two months. Results: Main results were that the facets of alexithymia were differentially associated with pain perception. The affective scale difficulties in describing feelings was associated with hyposensitivity to pain as indicated by higher pain tolerance scores. Furthermore, everyday pain frequency was related to increased alexithymia values on the affective scale difficulties in identifying feelings, whereas higher values on the cognitive alexithymia scale externally oriented thinking were related to lower pain impairment and intensity. Conclusions: We conclude that the different facets of alexithymia are related to alternations in pain processing. Further research on clinical samples is necessary to elucidate whether different aspects of alexithymia act as vulnerability factor for the development of pain symptoms.

Autism Spectrum Disorder and Amplified Pain

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Ciaran Clarke

2015-01-01

Full Text Available Among the core features of ASD, altered sensitivities in all modalities have been accorded increasing importance. Heightened sensitivity to pain and unusual expressions of and reaction to pain have not hitherto been widely recognised as a presenting feature of ASD in general paediatrics. Failure to recognise ASD as a common cause of pain can lead to late diagnosis, inappropriate treatment, distress, and further disability. Two cases are presented which illustrate the late presentation of Autism Spectrum Disorder (Asperger’s Syndrome subtype with chronic unusual pain. Conclusion. Pain in autism can be atypical in its experience and expression and for this reason may go unrecognised by physicians treating chronic pain disorders.

Increased medial foot loading during drop jump in subjects with patellofemoral pain

DEFF Research Database (Denmark)

Rathleff, Michael S; Richter, Camilla; Brushøj, Christoffer

2014-01-01

PURPOSE: To compare medial-to-lateral plantar forces during drop jump and single leg squat in individuals with and without patellofemoral pain. METHODS: This cross-sectional study compared 23 young adults with patellofemoral pain to 20 age- and sex-matched controls without knee pain. The plantar...... pressure distribution was collected during drop jump and single leg squat using pressure-sensitive Pedar insoles, inserted into a standard flat shoe. The primary outcome was the medial-to-lateral force, quantified as the peak force under the medial forefoot as the percentage of force under the total...... forefoot during drop jump. Secondary outcomes included peak medial-to-lateral force during single leg squat and mean forces during drop jump and single leg squat. RESULTS: The primary outcome showed that individuals with patellofemoral pain had a 22 % higher medial-to-lateral peak force during drop jump...

Effects of naltrexone on pain sensitivity and mood in fibromyalgia: no evidence for endogenous opioid pathophysiology.

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Jarred W Younger

Full Text Available The pathophysiological mechanisms underlying fibromyalgia are still unknown, although some evidence points to endogenous opioid dysfunction. We examined how endogenous opioid antagonism affects pain and mood for women with and without fibromyalgia. Ten women with fibromyalgia and ten age- and gender-matched, healthy controls each attended two laboratory sessions. Each participant received naltrexone (50mg at one session, and placebo at the other session, in a randomized and double-blind fashion. Participants were tested for changes in sensitivity to heat, cold, and mechanical pain. Additionally, we collected measures of mood and opioid withdrawal symptoms during the laboratory sessions and at home the night following each session. At baseline, the fibromyalgia group exhibited more somatic complaints, greater sensory sensitivity, more opioid withdrawal somatic symptoms, and lower mechanical and cold pain-tolerance than did the healthy control group. Neither group experienced changes in pain sensitivity due to naltrexone administration. Naltrexone did not differentially affect self-reported withdrawal symptoms, or mood, in the fibromyalgia and control groups. Consistent with prior research, there was no evidence found for abnormal endogenous opioid activity in women with fibromyalgia.

Phosphatidylinositol 3-kinase is a key mediator of central sensitization in painful inflammatory conditions

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Pezet, Sophie; Marchand, Fabien; D'Mello, Richard; Grist, John; Clark, Anna K.; Malcangio, Marzia; Dickenson, Anthony H.; Williams, Robert J.; McMahon, Stephen B.

2010-01-01

Here we show that phosphatidylinositol 3-kinase (PI3K) is a key player in the establishment of central sensitization, the spinal cord phenomenon associated with persistent afferent inputs and contributing to chronic pain states. We demonstrated electrophysiologically that PI3K is required for the full expression of spinal neuronal wind-up. In an inflammatory pain model, intrathecal administration of LY294002, a potent PI3K inhibitor, dose-dependently inhibited pain related behavior. This effect was correlated with a reduction of the phosphorylation of extracellular signal-regulated kinase (ERK) and CaMKinase II. In addition, we observed a significant decrease in the phosphorylation of the NMDA receptor subunit NR2B, decreased translocation to the plasma membrane of the GluR1 AMPA receptor subunit in the spinal cord and a reduction of evoked neuronal activity as measured using c-Fos immunohistochemistry. Our study suggests that PI3K is a major factor in the expression of central sensitization after noxious inflammatory stimuli. PMID:18417706

Effects of fluoxetine on changes of pain sensitivity in chronic stress model rats.

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Lian, Yan-Na; Chang, Jin-Long; Lu, Qi; Wang, Yi; Zhang, Ying; Zhang, Feng-Min

2017-06-09

Exposure to stress could facilitate or inhibit pain responses (stress-induced hyperalgesia or hypoalgesia, respectively). Fluoxetine is a selective serotonin (5-HT) reuptake inhibitor antidepressant. There have been contradictory reports on whether fluoxetine produces antinociceptive effects. The purpose of this study was to elucidate changes in pain sensitivity after chronic stress exposure, and the effects of fluoxetine on these changes. We measured thermal, mechanical, and formalin-induced acute and inflammatory pain by using the tail-flick, von Frey, and formalin tests respectively. The results showed that rats exposed to chronic stress exhibited thermal and formalin-induced acute and inflammatory hypoalgesia and transient mechanical hyperalgesia. Furthermore, fluoxetine promoted hypoalgesia in thermal and inflammatory pain and induced mechanical hyperalgesia. Our results indicate that the 5-HT system could be involved in hypoalgesia of thermal and inflammatory pain and induce transient mechanical hyperalgesia after stress exposure. Copyright © 2017 Elsevier B.V. All rights reserved.

Nav1.7 expression is increased in painful human dental pulp

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Levinson S Rock

2008-04-01

Full Text Available Abstract Background Animal studies and a few human studies have shown a change in sodium channel (NaCh expression after inflammatory lesions, and this change is implicated in the generation of pain states. We are using the extracted human tooth as a model system to study peripheral pain mechanisms and here examine the expression of the Nav1.7 NaCh isoform in normal and painful samples. Pulpal sections were labeled with antibodies against: 1 Nav1.7, N52 and PGP9.5, and 2 Nav1.7, caspr (a paranodal protein used to identify nodes of Ranvier, and myelin basic protein (MBP, and a z-series of optically-sectioned images were obtained with the confocal microscope. Nav1.7-immunofluorescence was quantified in N52/PGP9.5-identified nerve fibers with NIH ImageJ software, while Nav1.7 expression in myelinated fibers at caspr-identified nodal sites was evaluated and further characterized as either typical or atypical as based on caspr-relationships. Results Results show a significant increase in nerve area with Nav1.7 expression within coronal and radicular fiber bundles and increased expression at typical and atypical caspr-identified nodal sites in painful samples. Painful samples also showed an augmentation of Nav1.7 within localized areas that lacked MBP, including those associated with atypical caspr-identified sites, thus identifying NaCh remodeling within demyelinating axons as the basis for a possible pulpal pain mechanism. Conclusion This study identifies the increased axonal expression and augmentation of Nav1.7 at intact and remodeling/demyelinating nodes within the painful human dental pulp where these changes may contribute to constant, increased evoked and spontaneous pain responses that characterize the pain associated with toothache.

Increased auditory startle reflex in children with functional abdominal pain.

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Bakker, Mirte J; Boer, Frits; Benninga, Marc A; Koelman, Johannes H T M; Tijssen, Marina A J

2010-02-01

To test the hypothesis that children with abdominal pain-related functional gastrointestinal disorders have a general hypersensitivity for sensory stimuli. Auditory startle reflexes were assessed in 20 children classified according to Rome III classifications of abdominal pain-related functional gastrointestinal disorders (13 irritable bowel syndrome [IBS], 7 functional abdominal pain syndrome; mean age, 12.4 years; 15 girls) and 23 control subjects (14 girls; mean age, 12.3 years) using a case-control design. The activity of 6 left-sided muscles and the sympathetic skin response were obtained by an electromyogram. We presented sudden loud noises to the subjects through headphones. Both the combined response of 6 muscles and the blink response proved to be significantly increased in patients with abdominal pain compared with control subjects. A significant increase of the sympathetic skin response was not found. Comorbid anxiety disorders (8 patients with abdominal pain) or Rome III subclassification did not significantly affect these results. This study demonstrates an objective hyperresponsivity to nongastrointestinal stimuli. Children with abdominal pain-related functional gastrointestinal disorders may have a generalized hypersensitivity of the central nervous system. Copyright 2010 Mosby, Inc. All rights reserved.

Adaptability to pain is associated with potency of local pain inhibition, but not conditioned pain modulation: a healthy human study.

Science.gov (United States)

Zheng, Zhen; Wang, Kelun; Yao, Dongyuan; Xue, Charlie C L; Arendt-Nielsen, Lars

2014-05-01

This study investigated the relationship between pain sensitivity, adaptability, and potency of endogenous pain inhibition, including conditioned pain modulation (CPM) and local pain inhibition. Forty-one healthy volunteers (20 male, 21 female) received conditioning stimulation (CS) over 2 sessions in a random order: tonic heat pain (46 °C) on the right leg for 7 minutes and cold pressor pain (1 °C to 4 °C) on the left hand for 5 minutes. Participants rated the intensity of pain continuously using a 0 to 10 electronic visual analogue scale. The primary outcome measures were pressure pain thresholds (PPT) measured at the heterotopic and homotopic location to the CS sites before, during, and 20 minutes after CS. Two groups of participants, pain adaptive and pain nonadaptive, were identified based on their response to pain in the cold pressor test. Pain-adaptive participants showed a pain reduction between peak pain and pain at end of the test by at least 2 of 10 (n=16); whereas the pain-nonadaptive participants reported unchanged peak pain during 5-minute CS (n=25). Heterotopic PPTs during the CS did not differ between the 2 groups. However, increased homotopic PPTs measured 20 minutes after CS correlated with the amount of pain reduction during CS. These results suggest that individual sensitivity and adaptability to pain does not correlate with the potency of CPM. Adaptability to pain is associated with longer-lasting local pain inhibition. Copyright © 2014 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

JNK-induced MCP-1 production in spinal cord astrocytes contributes to central sensitization and neuropathic pain.

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Gao, Yong-Jing; Zhang, Ling; Samad, Omar Abdel; Suter, Marc R; Yasuhiko, Kawasaki; Xu, Zhen-Zhong; Park, Jong-Yeon; Lind, Anne-Li; Ma, Qiufu; Ji, Ru-Rong

2009-04-01

Our previous study showed that activation of c-jun-N-terminal kinase (JNK) in spinal astrocytes plays an important role in neuropathic pain sensitization. We further investigated how JNK regulates neuropathic pain. In cultured astrocytes, tumor necrosis factor alpha (TNF-alpha) transiently activated JNK via TNF receptor-1. Cytokine array indicated that the chemokine CCL2/MCP-1 (monocyte chemoattractant protein-1) was strongly induced by the TNF-alpha/JNK pathway. MCP-1 upregulation by TNF-alpha was dose dependently inhibited by the JNK inhibitors SP600125 (anthra[1,9-cd]pyrazol-6(2H)-one) and D-JNKI-1. Spinal injection of TNF-alpha produced JNK-dependent pain hypersensitivity and MCP-1 upregulation in the spinal cord. Furthermore, spinal nerve ligation (SNL) induced persistent neuropathic pain and MCP-1 upregulation in the spinal cord, and both were suppressed by D-JNKI-1. Remarkably, MCP-1 was primarily induced in spinal cord astrocytes after SNL. Spinal administration of MCP-1 neutralizing antibody attenuated neuropathic pain. Conversely, spinal application of MCP-1 induced heat hyperalgesia and phosphorylation of extracellular signal-regulated kinase in superficial spinal cord dorsal horn neurons, indicative of central sensitization (hyperactivity of dorsal horn neurons). Patch-clamp recordings in lamina II neurons of isolated spinal cord slices showed that MCP-1 not only enhanced spontaneous EPSCs but also potentiated NMDA- and AMPA-induced currents. Finally, the MCP-1 receptor CCR2 was expressed in neurons and some non-neuronal cells in the spinal cord. Together, we have revealed a previously unknown mechanism of MCP-1 induction and action. MCP-1 induction in astrocytes after JNK activation contributes to central sensitization and neuropathic pain facilitation by enhancing excitatory synaptic transmission. Inhibition of the JNK/MCP-1 pathway may provide a new therapy for neuropathic pain management.

Self-perceived weather sensitivity and joint pain in older people with osteoarthritis in six European countries: results from the European Project on OSteoArthritis (EPOSA).

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Timmermans, Erik J; van der Pas, Suzan; Schaap, Laura A; Sánchez-Martínez, Mercedes; Zambon, Sabina; Peter, Richard; Pedersen, Nancy L; Dennison, Elaine M; Denkinger, Michael; Castell, Maria Victoria; Siviero, Paola; Herbolsheimer, Florian; Edwards, Mark H; Otero, Angel; Deeg, Dorly J H

2014-03-05

People with osteoarthritis (OA) frequently report that their joint pain is influenced by weather conditions. This study aimed to examine whether there are differences in perceived joint pain between older people with OA who reported to be weather-sensitive versus those who did not in six European countries with different climates and to identify characteristics of older persons with OA that are most predictive of perceived weather sensitivity. Baseline data from the European Project on OSteoArthritis (EPOSA) were used. ACR classification criteria were used to determine OA. Participants with OA were asked about their perception of weather as influencing their pain. Using a two-week follow-up pain calendar, average self-reported joint pain was assessed (range: 0 (no pain)-10 (greatest pain intensity)). Linear regression analyses, logistic regression analyses and an independent t-test were used. Analyses were adjusted for several confounders. The majority of participants with OA (67.2%) perceived the weather as affecting their pain. Weather-sensitive participants reported more pain than non-weather-sensitive participants (M = 4.1, SD = 2.4 versus M = 3.1, SD = 2.4; p weather sensitivity and joint pain remained present (B = 0.37, p = 0.03). Logistic regression analyses revealed that women and more anxious people were more likely to report weather sensitivity. Older people with OA from Southern Europe were more likely to indicate themselves as weather-sensitive persons than those from Northern Europe. Weather (in)stability may have a greater impact on joint structures and pain perception in people from Southern Europe. The results emphasize the importance of considering weather sensitivity in daily life of older people with OA and may help to identify weather-sensitive older people with OA.

Repeated noxious stimulation of the skin enhances cutaneous pain perception of migraine patients in-between attacks: clinical evidence for continuous sub-threshold increase in membrane excitability of central trigeminovascular neurons.

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Weissman-Fogel, Irit; Sprecher, Elliot; Granovsky, Yelena; Yarnitsky, David

2003-08-01

Recent clinical studies showed that acute migraine attacks are accompanied by increased periorbital and bodily skin sensitivity to touch, heat and cold. Parallel pre-clinical studies showed that the underlying mechanism is sensitization of primary nociceptors and central trigeminovascular neurons. The present study investigates the sensory state of neuronal pathways that mediate skin pain sensation in migraine patients in between attacks. The assessments of sensory perception included (a) mechanical and thermal pain thresholds of the periorbital area, electrical pain threshold of forearm skin, (b) pain scores to phasic supra-threshold stimuli in the same modalities and areas as above, and (c) temporal summation of pain induced by applying noxious tonic heat pain and brief trains of noxious mechanical and electrical pulses to the above skin areas. Thirty-four pain-free migraine patients and 28 age- and gender-matched controls were studied. Patients did not differ from controls in their pain thresholds for heat (44+/-2.6 vs. 44.6+/-1.9 degrees C), and electrical (4.8+/-1.6 vs. 4.3+/-1.6 mA) stimulation, and in their pain scores for supra-threshold phasic stimuli for all modalities. They did, however, differ in their pain threshold for mechanical stimulation, just by one von Frey filament (P=0.01) and in their pain scores of the temporal summation tests. Increased summation of pain was found in migraineurs for repeated mechanical stimuli (delta visual analog scale (VAS) +2.32+/-0.73 in patients vs. +0.16+/-0.83 in controls, P=0.05) and repeated electrical stimuli (delta VAS +3.83+/-1.91 vs -3.79+/-2.31, P=0.01). Increased summation corresponded with more severe clinical parameters of migraine and tended to depend on interval since last migraine attack. The absence of clinically or overt laboratory expressed allodynia suggests that pain pathways are not sensitized in the pain-free migraine patients. Nevertheless, the increased temporal summation, and the slight

Influence of TRPV1 on diabetes-induced alterations in thermal pain sensitivity

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Pauza Mary E

2008-03-01

Full Text Available Abstract A common complication associated with diabetes is painful or painless diabetic peripheral neuropathy (DPN. The mechanisms and determinants responsible for these peripheral neuropathies are poorly understood. Using both streptozotocin (STZ-induced and transgene-mediated murine models of type 1 diabetes (T1D, we demonstrate that Transient Receptor Potential Vanilloid 1 (TRPV1 expression varies with the neuropathic phenotype. We have found that both STZ- and transgene-mediated T1D are associated with two distinct phases of thermal pain sensitivity that parallel changes in TRPV1 as determined by paw withdrawal latency (PWL. An early phase of hyperalgesia and a late phase of hypoalgesia are evident. TRPV1-mediated whole cell currents are larger and smaller in dorsal root ganglion (DRG neurons collected from hyperalgesic and hypoalgesic mice. Resiniferatoxin (RTX binding, a measure of TRPV1 expression is increased and decreased in DRG and paw skin of hyperalgesic and hypoalgesic mice, respectively. Immunohistochemical labeling of spinal cord lamina I and II, dorsal root ganglion (DRG, and paw skin from hyperalgesic and hypoalgesic mice reveal increased and decreased TRPV1 expression, respectively. A role for TRPV1 in thermal DPN is further suggested by the failure of STZ treatment to influence thermal nociception in TRPV1 deficient mice. These findings demonstrate that altered TRPV1 expression and function contribute to diabetes-induced changes in thermal perception.

Increased energy expenditure and glucose oxidation during acute nontraumatic skin pain in humans.

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Holland-Fischer, Peter; Greisen, Jacob; Grøfte, Thorbjørn; Jensen, Troels S; Hansen, Peter O; Vilstrup, Hendrik

2009-04-01

Tissue injury is accompanied by pain and results in increased energy expenditure, which may promote catabolism. The extent to which pain contributes to this sequence of events is not known. In a cross-over design, 10 healthy volunteers were examined on three occasions; first, during self-controlled nontraumatic electrical painful stimulus to the abdominal skin, maintaining an intensity of 8 on the visual analogue scale (0-10). Next, the electrical stimulus was reproduced during local analgesia and, finally, there was a control session without stimulus. Indirect calorimetry and blood and urine sampling was done in order to calculate energy expenditure and substrate utilization. During pain stimulus, energy expenditure increased acutely and reversibly by 62% (95% confidence interval, 43-83), which was abolished by local analgesia. Energy expenditure paralleled both heart rate and blood catecholamine levels. The energy expenditure increase was fuelled by all energy sources, with the largest increase in glucose utilization. The pain-related increase in energy expenditure was possibly mediated by adrenergic activity and was probably to a large extent due to increased muscle tone. These effects may be enhanced by cortical events related to the pain. The increase in glucose consumption favours catabolism. Our findings emphasize the clinical importance of pain management.

The Sensitivity to Change and Responsiveness of the Adult Responses to Children’s Symptoms in Children and Adolescents With Chronic Pain

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Alberts, Nicole; Langer, Shelby L.; Levy, Rona L.; Walker, Lynn S.; Palermo, Tonya M.

2016-01-01

Abstract Objective  To examine the sensitivity to change and responsiveness of the Adult Responses to Children’s Symptoms (ARCS) among parents of youth with chronic pain.  Methods  Participants included 330 youth (89 children aged 7–11 years, 241 children aged 12–17 years) and their parents who participated in randomized controlled trials of family-based cognitive-behavioral therapy for chronic pain. Child pain and disability, parental emotional functioning, and parental responses to child pain were assessed at baseline and posttreatment.  Results  The Protect and Monitor scales of the ARCS were sensitive to change following intervention for both developmental groups, with clinically meaningful reductions in these behaviors, thereby demonstrating responsiveness. Among the adolescent sample, greater change on some ARCS scales was associated with better parental emotional functioning and lower child pain at posttreatment.  Conclusions  Findings support the sensitivity to change and responsiveness of the Protect and Monitor scales among parents of youth with chronic pain. PMID:26493601

Association between Gene Polymorphisms and Pain Sensitivity Assessed in a Multi-Modal Multi-Tissue Human Experimental Model - An Explorative Study

DEFF Research Database (Denmark)

Nielsen, Lecia Møller; Olesen, Anne Estrup; Sato, Hiroe

2016-01-01

The genetic influence on sensitivity to noxious stimuli (pain sensitivity) remains controversial and needs further investigation. In the present study, the possible influence of polymorphisms in three opioid receptor (OPRM, OPRD and OPRK) genes and the catechol-O-methyltransferase (COMT) gene...... on pain sensitivity in healthy participants was investigated. Catechol-O-methyltransferase has an indirect effect on the mu opioid receptor by changing its activity through an altered endogenous ligand effect. Blood samples for genetic analysis were withdrawn in a multi-modal and multi-tissue experimental......, electrical and thermal visceral stimulations. A cold pressor test was also conducted. DNA was available from 38 of 40 participants. Compared to non-carriers of the COMT rs4680A allele, carriers reported higher bone pressure pain tolerance threshold (i.e. less pain) by up to 23.8% (p

Suprathreshold Heat Pain Response Predicts Activity-Related Pain, but Not Rest-Related Pain, in an Exercise-Induced Injury Model

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Coronado, Rogelio A.; Simon, Corey B.; Valencia, Carolina; Parr, Jeffrey J.; Borsa, Paul A.; George, Steven Z.

2014-01-01

Exercise-induced injury models are advantageous for studying pain since the onset of pain is controlled and both pre-injury and post-injury factors can be utilized as explanatory variables or predictors. In these studies, rest-related pain is often considered the primary dependent variable or outcome, as opposed to a measure of activity-related pain. Additionally, few studies include pain sensitivity measures as predictors. In this study, we examined the influence of pre-injury and post-injury factors, including pain sensitivity, for induced rest and activity-related pain following exercise induced muscle injury. The overall goal of this investigation was to determine if there were convergent or divergent predictors of rest and activity-related pain. One hundred forty-three participants provided demographic, psychological, and pain sensitivity information and underwent a standard fatigue trial of resistance exercise to induce injury of the dominant shoulder. Pain at rest and during active and resisted shoulder motion were measured at 48- and 96-hours post-injury. Separate hierarchical models were generated for assessing the influence of pre-injury and post-injury factors on 48- and 96-hour rest-related and activity-related pain. Overall, we did not find a universal predictor of pain across all models. However, pre-injury and post-injury suprathreshold heat pain response (SHPR), a pain sensitivity measure, was a consistent predictor of activity-related pain, even after controlling for known psychological factors. These results suggest there is differential prediction of pain. A measure of pain sensitivity such as SHPR appears more influential for activity-related pain, but not rest-related pain, and may reflect different underlying processes involved during pain appraisal. PMID:25265560

Monosodium iodoacetate-induced joint pain is associated with increased phosphorylation of mitogen activated protein kinases in the rat spinal cord

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Jarvis Michael F

2011-05-01

Full Text Available Abstract Background Intra-articular injection of monosodium iodoacetate (MIA in the knee joint of rats disrupts chondrocyte metabolism resulting in cartilage degeneration and subsequent nociceptive behavior that has been described as a model of osteoarthritis (OA pain. Central sensitization through activation of mitogen activated protein kinases (MAPKs is recognized as a pathogenic mechanism in chronic pain. In the present studies, induction of central sensitization as indicated by spinal dorsal horn MAPK activation, specifically ERK and p38 phosphorylation, was assessed in the MIA-OA model. Results Behaviorally, MIA-injected rats displayed reduced hind limb grip force 1, 2, and 3 weeks post-MIA treatment. In the same animals, activation of phospho ERK1/2 was gradually increased, reaching a significant level at post injection week 3. Conversely, phosphorylation of p38 MAPK was enhanced maximally at post injection week 1 and decreased, but remained elevated, thereafter. Double labeling from 3-wk MIA rats demonstrated spinal pERK1/2 expression in neurons, but not glia. In contrast, p-p38 was expressed by microglia and a subpopulation of neurons, but not astrocytes. Additionally, there was increased ipsilateral expression of microglia, but not astrocytes, in 3-wk MIA-OA rats. Consistent with increased MAPK immunoreactivity in the contralateral dorsal horn, mechanical allodynia to the contralateral hind-limb was observed 3-wk following MIA. Finally, intrathecal injection of the MEK1 inhibitor PD98059 blocked both reduced hind-limb grip force and pERK1/2 induction in MIA-OA rats. Conclusion Results of these studies support the role of MAPK activation in the progression and maintenance of central sensitization in the MIA-OA experimental pain model.

The association between pressure pain sensitivity, and answers to questionnaires estimating psychological stress level in the workplace. A feasibility study

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Ballegaard, Søren; Petersen, Pernille; Gyntelberg, Finn

2012-01-01

To examine the association between pressure pain sensitivity (PPS) at the sternum as a measure of persistent stress assessed by questionnaires in a working population.......To examine the association between pressure pain sensitivity (PPS) at the sternum as a measure of persistent stress assessed by questionnaires in a working population....

Omeprazole increases the efficacy of a soluble epoxide hydrolase inhibitor in a PGE2 induced pain model

International Nuclear Information System (INIS)

Goswami, Sumanta Kumar; Inceoglu, Bora; Yang, Jun; Wan, Debin; Kodani, Sean D.; Trindade da Silva, Carlos Antonio; Morisseau, Christophe; Hammock, Bruce D.

2015-01-01

Epoxyeicosatrienoic acids (EETs) are potent endogenous analgesic metabolites produced from arachidonic acid by cytochrome P450s (P450s). Metabolism of EETs by soluble epoxide hydrolase (sEH) reduces their activity, while their stabilization by sEH inhibition decreases both inflammatory and neuropathic pain. Here, we tested the complementary hypothesis that increasing the level of EETs through induction of P450s by omeprazole (OME), can influence pain related signaling by itself, and potentiate the anti-hyperalgesic effect of sEH inhibitor. Rats were treated with OME (100 mg/kg/day, p.o., 7 days), sEH inhibitor TPPU (3 mg/kg/day, p.o.) and OME (100 mg/kg/day, p.o., 7 days) + TPPU (3 mg/kg/day, p.o., last 3 days of OME dose) dissolved in vehicle PEG400, and their effect on hyperalgesia (increased sensitivity to pain) induced by PGE 2 was monitored. While OME treatment by itself exhibited variable effects on PGE 2 induced hyperalgesia, it strongly potentiated the effect of TPPU in the same assay. The significant decrease in pain with OME + TPPU treatment correlated with the increased levels of EETs in plasma and increased activities of P450 1A1 and P450 1A2 in liver microsomes. The results show that reducing catabolism of EETs with a sEH inhibitor yielded a stronger analgesic effect than increasing generation of EETs by OME, and combination of both yielded the strongest pain reducing effect under the condition of this study. - Highlights: • The soluble epoxide hydrolase (sEH) inhibitor TPPU is anti-hyperalgesic. • Omeprazole potentiates the anti-hyperalgesic actions of TPPU. • This potentiation is associated with increased P450 activity. • The potentiation is associated with an increase in fatty acid epoxide/diol ratio. • Joint use of sEH inhibitors and P450 inducers could result in drug–drug interactions.

Pressure pain sensitivity as a marker for stress and pressure pain sensitivity-guided stress management in women with primary breast cancer.

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Axelsson, Christen K; Ballegaard, Søren; Karpatschof, Benny; Schousen, Peer

2014-08-01

To validate (1) Pressure Pain Sensitivity (PPS) as a marker for stress and (2) a PPS-guided intervention in women with primary Breast Cancer (BC). (1) A total of 58 women with BC were examined before and after 6 months of intervention. A control group of 165 women office employees was divided in a High Stress Group (HSG, n = 37) and a Low Stress Group (LSG, n = 128) to evaluate the association between PPS, questionnaire-related Quality of Life (QOL) and self-evaluated stress. (2) A PPS-guided stress management program (n = 40) was compared to a Psychosocial Group Intervention (PGI, n = 91) and no treatment (n = 86) with respect to a European Organization for Research and Treatment of Cancer (EORTC) questionnaire measured QOL. (1) Resting PPS and changes in PPS during the intervention period correlated significantly to EORTC and Short Form 36 (SF 36) main scores: (all p stress scores (all p stress. (2) The PPS-guided intervention group improved EORTC main score, pain and nausea, when compared to the control groups (all p stress. PPS-guided intervention improved QOL in women with breast cancer.

Pressure pain sensitivity as a marker for stress and pressure pain sensitivity-guided stress management in women with primary breast cancer

DEFF Research Database (Denmark)

Axelsson, Christen K; Ballegaard, Søren; Karpatschof, Benny

2014-01-01

employees was divided in a High Stress Group (HSG, n = 37) and a Low Stress Group (LSG, n = 128) to evaluate the association between PPS, questionnaire-related Quality of Life (QOL) and self-evaluated stress. (2) A PPS-guided stress management program (n = 40) was compared to a Psychosocial Group......OBJECTIVES: To validate (1) Pressure Pain Sensitivity (PPS) as a marker for stress and (2) a PPS-guided intervention in women with primary Breast Cancer (BC). METHODS: (1) A total of 58 women with BC were examined before and after 6 months of intervention. A control group of 165 women office...... scores: (all p stress scores (all p

Night-shift work increases cold pain perception.

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Pieh, Christoph; Jank, Robert; Waiß, Christoph; Pfeifer, Christian; Probst, Thomas; Lahmann, Claas; Oberndorfer, Stefan

2018-05-01

Although night-shift work (NSW) is associated with a higher risk for several physical and mental disorders, the impact of NSW on pain perception is still unclear. This study investigates the impact of NSW on cold pain perception considering the impact of mood and sleepiness. Quantitative sensory testing (QST) was performed in healthy night-shift workers. Cold pain threshold as well as tonic cold pain was assessed after one habitual night (T1), after a 12-hour NSW (T2) and after one recovery night (T3). Sleep quality was measured with the Pittsburgh Sleep Quality Index (PSQI) before T1, sleepiness with the Stanford Sleepiness Scale (SSS) and mood with a German short-version of the Profile of Mood States (ASTS) at T1, T2 and T3. Depending on the distribution of the data, ANOVAs or Friedman tests as well as t- or Wilcoxon tests were performed. Nineteen healthy shift-workers (13 females; 29.7 ± 7.5 years old; 8.1 ± 6.6 years in shift work, PSQI: 4.7 ± 2.2) were included. Tonic cold pain showed a significant difference between T1 (48.2 ± 27.5 mm), T2 (61.7 ± 26.6 mm; effect size: Cohen's d=.49; percent change 28%), and T3 (52.1 ± 28.7 mm) on a 0-100 mm Visual Analog Scale (p = 0.007). Cold pain threshold changed from 11.0 ± 7.9 °C (T1) to 14.5 ± 8.8 °C (T2) (p = 0.04), however, an ANOVA comparing T1, T2, and T3 was not significant (p = 0.095). Sleepiness (SSS) and mood (ASTS) changed significantly between T1, T2 and T3 (p-values night. Increases in cold pain perception due to NSW appear to be more strongly related to changes in mood as compared to changes in sleepiness. Copyright © 2018 Elsevier B.V. All rights reserved.

Reduction of pain-related fear and increased function and participation in work-related upper extremity pain (WRUEP): effects of exposure in vivo.

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de Jong, Jeroen R; Vlaeyen, Johan W S; van Eijsden, Marjon; Loo, Christoph; Onghena, Patrick

2012-10-01

There is increasing evidence that pain-related fear influences the development and maintenance of pain disability, presumably mediated through the fear-related avoidance of valued activities. Individually tailored graded exposure in vivo (GEXP) has been demonstrated to reduce pain-related fear and increase functional abilities in patients with chronic low back pain, neck pain, and complex regional pain syndrome. The current study aimed to test whether these effects generalize towards patients with work-related upper extremity pain. A sequential replicated and randomized single-case experimental phase design with multiple measurements was used. Within each participant, GEXP was compared to a no-treatment baseline period and a no-treatment 6-month follow-up period. Eight patients who reported a high level of pain-related fear were included in the study. Daily changes in pain catastrophizing, pain-related fear, and pain intensity were assessed using a diary, and subjected to randomization tests. Before the start of the baseline period, just after GEXP, and at 6-month follow-up, clinically relevant changes of pain catastrophizing, pain-related fear, perceived harmfulness of physical activity, pain disability, and participation/autonomy were verified. When GEXP was introduced, levels of pain catastrophizing and pain-related fear decreased significantly. Clinically relevant improvements were observed for pain disability, perceived participation, and autonomy. These favourable changes were maintained until 6-month follow-up. The findings of the current study underscore the external validity of a cognitive-behavioural GEXP treatment for patients with chronic pain reporting increased pain-related fear. Copyright © 2012 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Intravenous flurbiprofen axetil can increase analgesic effect in refractory cancer pain

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Hao Jiqing

2009-03-01

Full Text Available Abstract Background The aim of this study was to investigate the analgesic effects of intravenous flurbiprofen axetil for the refractory pain in cancer patients. Methods 2109 patients were screened from the department of medical oncology, the first affiliated hospital of Anhui medical university in China between October of 2007 and October of 2008. Thirty-seven cases of cancer patients who had bad effect from anaesthetic drugs were received administration of intravenous flurbiprofen axetil with dose of 50 mg/5 ml/day. The pain score was evaluated for pre- and post- treatment by Pain Faces Scale criteria, and the side effects were also observed. Results Intravenous flurbiprofen axetil increased the analgesic effects. The total effective rate was 92%. The side effects, such as abdominal pain, alimentary tract bleeding which were found in using NSAIDs or constipation, nausea, vomit, sleepiness which were found in using opioid drugs did not be found. Conclusion Intravenous flurbiprofen axetil could provide better analgesia effects and few side effects to patients with refractory cancer pain. It could also increase analgesia effects when combining with anesthetic drugs in treatment of moderate or severe pain, especially breakthrough pain, and suit to patients who can not take oral drugs for the reason of constipation and psychosomatic symptoms.

Intravenous flurbiprofen axetil can increase analgesic effect in refractory cancer pain

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Wu, Hongyang; Chen, Zhendong; Sun, Guoping; Gu, Kangsheng; Pan, Yueyin; Hao, Jiqing; Du, Yingying; Ning, Jie

2009-01-01

Background The aim of this study was to investigate the analgesic effects of intravenous flurbiprofen axetil for the refractory pain in cancer patients. Methods 2109 patients were screened from the department of medical oncology, the first affiliated hospital of Anhui medical university in China between October of 2007 and October of 2008. Thirty-seven cases of cancer patients who had bad effect from anaesthetic drugs were received administration of intravenous flurbiprofen axetil with dose of 50 mg/5 ml/day. The pain score was evaluated for pre- and post- treatment by Pain Faces Scale criteria, and the side effects were also observed. Results Intravenous flurbiprofen axetil increased the analgesic effects. The total effective rate was 92%. The side effects, such as abdominal pain, alimentary tract bleeding which were found in using NSAIDs or constipation, nausea, vomit, sleepiness which were found in using opioid drugs did not be found. Conclusion Intravenous flurbiprofen axetil could provide better analgesia effects and few side effects to patients with refractory cancer pain. It could also increase analgesia effects when combining with anesthetic drugs in treatment of moderate or severe pain, especially breakthrough pain, and suit to patients who can not take oral drugs for the reason of constipation and psychosomatic symptoms. PMID:19267934

Effect of a cooling gel on pain sensitivity and healing of hot-iron cattle brands.

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Tucker, C B; Mintline, E M; Banuelos, J; Walker, K A; Hoar, B; Drake, D; Weary, D M

2014-12-01

Hot-iron branding is painful for cattle, but little is known about how long this pain lasts or effective alleviation methods. Previous work with pigs indicated that cooling burns with a gel (active ingredient: tea tree oil) improved healing compared to untreated wounds. Steers (210±21 kg) were hot-iron branded and allocated to 1 of 3 treatments: control (n=24), 1 gel application immediately after branding (1X; n=12), or 2 gel applications, 1 immediately after branding and one 1 d later (2X; n=12). Pain sensitivity was assessed by applying a known and increasing force with a von Frey anesthesiometer in 5 locations (in the center, at the top of, and 5 and 10 cm above the brand and on the equivalent location on the nonbranded side of the body) until animals showed a behavioral response. Healing was measured with a 6-point scale (1=fresh brand and 6=no scabbing and fully repigmented). Both measures, along with weight gain and surface temperature of the wound, were recorded before and 1, 2, 3, 7, 14, 21, 28, 35, 56, and 70 d after branding. The gel cooled the brand, with the most obvious differences on the day it was applied (3.7 to 4.2°C cooler than control; day×gel interaction, P=0.004). All wounds were at least partially repigmented by 70 d, but only 46% of brands were fully healed at this time. The healing process was slowed when a gel was applied twice (e.g., at 21 d, healing score of 2.5±0.1 and 2.7±0.1 vs. 2.0±0.2 for control and 1X vs. 2X, respectively; P=0.001). Brands tended to remain painful throughout the 70 d (in the center of the brand; before vs. d 1-35, P≤0.001; d 56, P=0.058; and d 70, P=0.092). Overall, gel had little effect on pain sensitivity. Weight gain was reduced on d 1 after branding compared to all other time points (Pbranding. In addition, by 70 d after the procedure, hot-iron brands still tended to be more painful than nonbranded tissue and 54% were not fully healed. These results raise additional animal welfare concerns about hot

Use of Temporary Implantable Biomaterials to Reduce Leg Pain and Back Pain in Patients with Sciatica and Lumbar Disc Herniation

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Gere S. diZerega

2010-05-01

Full Text Available The principle etiology of leg pain (sciatica from lumbar disc herniation is mechanical compression of the nerve root. Sciatica is reduced by decompression of the herniated disc, i.e., removing mechanical compression of the nerve root. Decompression surgery typically reduces sciatica more than lumbar back pain (LBP. Decompression surgery reduces mechanical compression of the nerve root. However, decompression surgery does not directly reduce sensitization of the sensory nerves in the epidural space and disc. In addition, sensory nerves in the annulus fibrosus and epidural space are not protected from topical interaction with pain mediators induced by decompression surgery. The secondary etiology of sciatica from lumbar disc herniation is sensitization of the nerve root. Sensitization of the nerve root results from a mechanical compression, b exposure to cellular pain mediators, and/or c exposure to biochemical pain mediators. Although decompression surgery reduces nerve root compression, sensory nerve sensitization often persists. These observations are consistent with continued exposure of tissue in the epidural space, including the nerve root, to increased cellular and biochemical pain mediators following surgery. A potential contributor to lumbar back pain (LBP is stimulation of sensory nerves in the annulus fibrosus by a cellular pain mediators and/or b biochemical pain mediators that accompany annular tears or disruption. Sensory fibers located in the outer one-third of the annulus fibrosus increase in number and depth as a result of disc herniation. The nucleus pulposus is comprised of material that can produce an autoimmune stimulation of the sensory nerves located in the annulus and epidural space leading to LBP. The sensory nerves of the annulus fibrosus and epidural space may be sensitized by topical exposure to cellular and biochemical pain mediators induced by lumbar surgery. Annulotomy or annular rupture allows the nucleus pulposus

Cervico-ocular Reflex Is Increased in People With Nonspecific Neck Pain.

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de Vries, Jurryt; Ischebeck, Britta K; Voogt, Lennard P; Janssen, Malou; Frens, Maarten A; Kleinrensink, Gert-Jan; van der Geest, Jos N

2016-08-01

Neck pain is a widespread complaint. People experiencing neck pain often present an altered timing in contraction of cervical muscles. This altered afferent information elicits the cervico-ocular reflex (COR), which stabilizes the eye in response to trunk-to-head movements. The vestibulo-ocular reflex (VOR) elicited by the vestibulum is thought to be unaffected by afferent information from the cervical spine. The aim of the study was to measure the COR and VOR in people with nonspecific neck pain. This study utilized a cross-sectional design in accordance with the STROBE statement. An infrared eye-tracking device was used to record the COR and the VOR while the participant was sitting on a rotating chair in darkness. Eye velocity was calculated by taking the derivative of the horizontal eye position. Parametric statistics were performed. The mean COR gain in the control group (n=30) was 0.26 (SD=0.15) compared with 0.38 (SD=0.16) in the nonspecific neck pain group (n=37). Analyses of covariance were performed to analyze differences in COR and VOR gains, with age and sex as covariates. Analyses of covariance showed a significantly increased COR in participants with neck pain. The VOR between the control group, with a mean VOR of 0.67 (SD=0.17), and the nonspecific neck pain group, with a mean VOR of 0.66 (SD=0.22), was not significantly different. Measuring eye movements while the participant is sitting on a rotating chair in complete darkness is technically complicated. This study suggests that people with nonspecific neck pain have an increased COR. The COR is an objective, nonvoluntary eye reflex and an unaltered VOR. This study shows that an increased COR is not restricted to patients with traumatic neck pain. © 2016 American Physical Therapy Association.

Abnormalities of somatosensory perception in patients with painful osteoarthritis normalize following successful treatment.

Science.gov (United States)

Kosek, E; Ordeberg, G

2000-01-01

To investigate the effect of chronic nociceptive pain on somatosensory perception, quantitative sensibility testing was performed in the most painful area and the homologous contralateral side in 14 patients with painful osteoarthritis of the hip. Twelve patients were reassessed in a painfree state 6-14 months following surgery. Von Frey filaments were used to test low-threshold mechanoreceptive function. Pressure pain sensitivity was assessed with a pressure algometer and thermal sensitivity with a Thermotest. Sex- and age-matched controls were examined in the corresponding areas at similar time intervals. There was no statistically significant difference between groups in the sensitivity to light touch and innocuous cold in either session. Compared to controls, patients had increased sensitivity to pressure pain in the most painful area (p pain (ppain (p = 0.054) before surgery. In the painful area, patients' sensitivity to pressure pain decreased (p pain. Copyright 2000 European Federation of Chapters of the International Association for the Study of Pain.

Immediate changes in widespread pressure pain sensitivity, neck pain, and cervical range of motion after cervical or thoracic thrust manipulation in patients with bilateral chronic mechanical neck pain: a randomized clinical trial.

Science.gov (United States)

Martínez-Segura, Raquel; De-la-Llave-Rincón, Ana I; Ortega-Santiago, Ricardo; Cleland, Joshua A; Fernández-de-Las-Peñas, César

2012-09-01

Randomized clinical trial. To compare the effects of cervical versus thoracic thrust manipulation in patients with bilateral chronic mechanical neck pain on pressure pain sensitivity, neck pain, and cervical range of motion (CROM). Evidence suggests that spinal interventions can stimulate descending inhibitory pain pathways. To our knowledge, no study has investigated the neurophysiological effects of thoracic thrust manipulation in individuals with bilateral chronic mechanical neck pain, including widespread changes on pressure sensitivity. Ninety patients (51% female) were randomly assigned to 1 of 3 groups: cervical thrust manipulation on the right, cervical thrust manipulation on the left, or thoracic thrust manipulation. Pressure pain thresholds (PPTs) over the C5-6 zygapophyseal joint, lateral epicondyle, and tibialis anterior muscle, neck pain (11-point numeric pain rating scale), and cervical spine range of motion (CROM) were collected at baseline and 10 minutes after the intervention by an assessor blinded to the treatment allocation of the patients. Mixed-model analyses of covariance were used to examine the effects of the treatment on each outcome variable, with group as the between-subjects variable, time and side as the within-subject variables, and gender as the covariate. The primary analysis was the group-by-time interaction. No significant interactions were found with the mixed-model analyses of covariance for PPT level (C5-6, P>.210; lateral epicondyle, P>.186; tibialis anterior muscle, P>.268), neck pain intensity (P = .923), or CROM (flexion, P = .700; extension, P = .387; lateral flexion, P>.672; rotation, P>.192) as dependent variables. All groups exhibited similar changes in PPT, neck pain, and CROM (all, P.10). The results of the current randomized clinical trial suggest that cervical and thoracic thrust manipulation induce similar changes in PPT, neck pain intensity, and CROM in individuals with bilateral chronic mechanical neck pain

Hypofunctional TrkA Accounts for the Absence of Pain Sensitization in the African Naked Mole-Rat.

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Omerbašić, Damir; Smith, Ewan St J; Moroni, Mirko; Homfeld, Johanna; Eigenbrod, Ole; Bennett, Nigel C; Reznick, Jane; Faulkes, Chris G; Selbach, Matthias; Lewin, Gary R

2016-10-11

The naked mole-rat is a subterranean rodent lacking several pain behaviors found in humans, rats, and mice. For example, nerve growth factor (NGF), an important mediator of pain sensitization, fails to produce thermal hyperalgesia in naked mole-rats. The sensitization of capsaicin-sensitive TRPV1 ion channels is necessary for NGF-induced hyperalgesia, but naked mole-rats have fully functional TRPV1 channels. We show that exposing isolated naked mole-rat nociceptors to NGF does not sensitize TRPV1. However, the naked mole-rat NGF receptor TrkA displays a reduced ability to engage signal transduction pathways that sensitize TRPV1. Between one- and three-amino-acid substitutions in the kinase domain of the naked mole-rat TrkA are sufficient to render the receptor hypofunctional, and this is associated with the absence of heat hyperalgesia. Our data suggest that evolution has selected for a TrkA variant that abolishes a robust nociceptive behavior in this species but is still compatible with species fitness. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Hypofunctional TrkA Accounts for the Absence of Pain Sensitization in the African Naked Mole-Rat

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Damir Omerbašić

2016-10-01

Full Text Available The naked mole-rat is a subterranean rodent lacking several pain behaviors found in humans, rats, and mice. For example, nerve growth factor (NGF, an important mediator of pain sensitization, fails to produce thermal hyperalgesia in naked mole-rats. The sensitization of capsaicin-sensitive TRPV1 ion channels is necessary for NGF-induced hyperalgesia, but naked mole-rats have fully functional TRPV1 channels. We show that exposing isolated naked mole-rat nociceptors to NGF does not sensitize TRPV1. However, the naked mole-rat NGF receptor TrkA displays a reduced ability to engage signal transduction pathways that sensitize TRPV1. Between one- and three-amino-acid substitutions in the kinase domain of the naked mole-rat TrkA are sufficient to render the receptor hypofunctional, and this is associated with the absence of heat hyperalgesia. Our data suggest that evolution has selected for a TrkA variant that abolishes a robust nociceptive behavior in this species but is still compatible with species fitness.

HYPNOBIRTHING INCREASE PAIN TOLERANCE AND ANXIETY IN ACTIVE PHASE LABOR

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Nursalam Nursalam

2017-07-01

Full Text Available Introduction: The main problem of inpartu mother was a labour pain and anxiety. The etiology of labour pain has been determained by dilatation and cervic’s tickness. The objective of this study was to examine the effect of hypnobirthing relaxation on the pain tolerance and anxiety responses in labor. Method: A pre experimental static group comparison purposive sampling design was used in this study. Population were all pregnant women in age of pregnancies between 38 until 39 weeks at RSUD Wangaya Denpasar. There were 12 respondents who met to the inclusion criteria divided into 6 respondents were given hypnobirthing relaxation intervention and 6 respondents as the control group. The independent variable was hypnobirthing relaxation and dependent variables were tolerance of pain and anxiety responses. Data were collected by using observation and questionnaire, then data were analyzed by using Mann Whitney U Test with significance level p=0.05. Result: The result showed that hypnobirthing relaxation had an effect on the pain tolerance and anxiety responses (p=0.015. Discussion: It can be concluded that the hypnobirthing relaxation has an effect to increase the pain tolerance and to decrease anxiety responses in active phase of labour. It is recommended to the hospital that have an ante natal care to hypnobirthing relaxation technique. Further studies should measure the effect of hynobirthing relaxation on increasing of β-endorfin in active phase labour.

A clinical perspective on a pain neuroscience education approach to manual therapy.

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Louw, Adriaan; Nijs, Jo; Puentedura, Emilio J

2017-07-01

In recent years, there has been an increased interest in pain neuroscience education (PNE) in physical therapy. There is growing evidence for the efficacy of PNE to decrease pain, disability, fear-avoidance, pain catastrophization, limited movement, and health care utilization in people struggling with pain. PNE teaches people in pain more about the biology and physiology of their pain experience including processes such as central sensitization, peripheral sensitization, allodynia, inhibition, facilitation, neuroplasticity and more. PNE's neurobiological model often finds itself at odds with traditional biomedical models used in physical therapy. Traditional biomedical models, focusing on anatomy, pathoanatomy, and biomechanics have been shown to have limited efficacy in helping people understand their pain, especially chronic pain, and may in fact even increase a person's pain experience by increasing fear-avoidance and pain catastrophization. An area of physical therapy where the biomedical model is used a lot is manual therapy. This contrast between PNE and manual therapy has seemingly polarized followers from each approach to see PNE as a 'hands-off' approach even having clinicians categorize patients as either in need of receiving PNE (with no hands-on), or hands-on with no PNE. In this paper, we explore the notion of PNE and manual therapy co-existing. PNE research has shown to have immediate effects of various clinical signs and symptoms associated with central sensitization. Using a model of sensitization (innocuous, noxious, and allodynia), we argue that PNE can be used in a manual therapy model, especially treating someone where the nervous system has become increasingly hypervigilant. Level of Evidence : VII.

Omeprazole increases the efficacy of a soluble epoxide hydrolase inhibitor in a PGE{sub 2} induced pain model

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Goswami, Sumanta Kumar; Inceoglu, Bora; Yang, Jun; Wan, Debin; Kodani, Sean D. [Department of Entomology and Nematology, UC Davis Comprehensive Cancer Center, University of California, Davis, CA (United States); Trindade da Silva, Carlos Antonio [Department of Entomology and Nematology, UC Davis Comprehensive Cancer Center, University of California, Davis, CA (United States); Department of Genetics and Biochemistry, Federal University of Uberlandia, MG (Brazil); Morisseau, Christophe [Department of Entomology and Nematology, UC Davis Comprehensive Cancer Center, University of California, Davis, CA (United States); Hammock, Bruce D., E-mail: bdhammock@ucdavis.edu [Department of Entomology and Nematology, UC Davis Comprehensive Cancer Center, University of California, Davis, CA (United States)

2015-12-15

Epoxyeicosatrienoic acids (EETs) are potent endogenous analgesic metabolites produced from arachidonic acid by cytochrome P450s (P450s). Metabolism of EETs by soluble epoxide hydrolase (sEH) reduces their activity, while their stabilization by sEH inhibition decreases both inflammatory and neuropathic pain. Here, we tested the complementary hypothesis that increasing the level of EETs through induction of P450s by omeprazole (OME), can influence pain related signaling by itself, and potentiate the anti-hyperalgesic effect of sEH inhibitor. Rats were treated with OME (100 mg/kg/day, p.o., 7 days), sEH inhibitor TPPU (3 mg/kg/day, p.o.) and OME (100 mg/kg/day, p.o., 7 days) + TPPU (3 mg/kg/day, p.o., last 3 days of OME dose) dissolved in vehicle PEG400, and their effect on hyperalgesia (increased sensitivity to pain) induced by PGE{sub 2} was monitored. While OME treatment by itself exhibited variable effects on PGE{sub 2} induced hyperalgesia, it strongly potentiated the effect of TPPU in the same assay. The significant decrease in pain with OME + TPPU treatment correlated with the increased levels of EETs in plasma and increased activities of P450 1A1 and P450 1A2 in liver microsomes. The results show that reducing catabolism of EETs with a sEH inhibitor yielded a stronger analgesic effect than increasing generation of EETs by OME, and combination of both yielded the strongest pain reducing effect under the condition of this study. - Highlights: • The soluble epoxide hydrolase (sEH) inhibitor TPPU is anti-hyperalgesic. • Omeprazole potentiates the anti-hyperalgesic actions of TPPU. • This potentiation is associated with increased P450 activity. • The potentiation is associated with an increase in fatty acid epoxide/diol ratio. • Joint use of sEH inhibitors and P450 inducers could result in drug–drug interactions.

Short-term pre- and post-operative stress prolongs incision-induced pain hypersensitivity without changing basal pain perception

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Cao, Jing; Wang, Po-Kai; Tiwari, Vinod; Liang, Lingli; Lutz, Brianna Marie; Shieh, Kun-Ruey; Zang, Wei-Dong; Kaufman, Andrew G.; Bekker, Alex; Gao, Xiao-Qun; Tao, Yuan-Xiang

2015-01-01

Background Chronic stress has been reported to increase basal pain sensitivity and/or exacerbate existing persistent pain. However, most surgical patients have normal physiological and psychological health status such as normal pain perception before surgery although they do experience short-term stress during pre- and post-operative periods. Whether or not this short-term stress affects persistent postsurgical pain is unclear. Results In this study, we showed that pre- or post-surgical expos...

Neuro Emotional Technique for the treatment of trigger point sensitivity in chronic neck pain sufferers: A controlled clinical trial

OpenAIRE

Bablis, Peter; Pollard, Henry; Bonello, Rod

2008-01-01

Abstract Background Trigger points have been shown to be active in many myofascial pain syndromes. Treatment of trigger point pain and dysfunction may be explained through the mechanisms of central and peripheral paradigms. This study aimed to investigate whether the mind/body treatment of Neuro Emotional Technique (NET) could significantly relieve pain sensitivity of trigger points presenting in a cohort of chronic neck pain sufferers. Methods Sixty participants presenting to a private chiro...

Factors influencing the attitudes of cattle veterinarians, farmers, and claw trimmers towards the pain associated with the treatment of sole ulcers and the sensitivity to pain of dairy cows.

Science.gov (United States)

Becker, Johanna; Reist, Martin; Steiner, Adrian

2014-04-01

This study assessed the attitudes of personnel involved in therapeutic claw trimming of dairy cattle in Switzerland towards pain associated with sole ulcers and their treatment. Data from 77 farmers, 32 claw trimmers, and 137 cattle veterinarians were used. A large range of factors were associated with whether the respondents thought that anaesthesia during the treatment of sole ulcers was beneficial; these included year of graduation, work experience, attitude to costs of analgesia, perception of competition between veterinarians and claw trimmers, estimation of pain level associated with treatment, estimated sensitivity of dairy cows to pain, knowledge of the obligation to provide analgesia, and whether the respondent thought lesion size and occurrence of defensive behaviour by the cow were important. Respondents' estimation of the pain level associated with sole ulcer treatment was linked to frequency of therapeutic claw trimming, age, farmers' income, estimated knowledge of the benefits of analgesia, and estimated sensitivity of dairy cows to pain. The latter factor was associated with profession, frequency of therapeutic claw trimming, capability of pain recognition, opinion on the benefits of analgesia, knowledge of the obligation to provide analgesia, and self-estimation of the ability to recognise pain. Improving the knowledge of personnel involved in therapeutic claw trimming with regard to pain in dairy cows and how to alleviate it is crucial if management of pain associated with treatment of sole ulcer and the welfare of lame cows are to be optimised. Copyright © 2014 Elsevier Ltd. All rights reserved.

Sensory Disturbances, but Not Motor Disturbances, Induced by Sensorimotor Conflicts Are Increased in the Presence of Acute Pain

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Clémentine Brun

2017-07-01

Full Text Available Incongruence between our motor intention and the sensory feedback of the action (sensorimotor conflict induces abnormalities in sensory perception in various chronic pain populations, and to a lesser extent in pain-free individuals. The aim of this study was to simultaneously investigate sensory and motor disturbances evoked by sensorimotor conflicts, as well as to assess how they are influenced by the presence of acute pain. It was hypothesized that both sensory and motor disturbances would be increased in presence of pain, which would suggest that pain makes body representations less robust. Thirty healthy participants realized cyclic asymmetric movements of flexion-extension with both upper limbs in a robotized system combined to a 2D virtual environment. The virtual environment provided a visual feedback (VF about movements that was either congruent or incongruent, while the robotized system precisely measured motor performance (characterized by bilateral amplitude asymmetry and medio-lateral drift. Changes in sensory perception were assessed with a questionnaire after each trial. The effect of pain (induced with capsaicin was compared to three control conditions (no somatosensory stimulation, tactile distraction and proprioceptive masking. Results showed that while both sensory and motor disturbances were induced by sensorimotor conflicts, only sensory disturbances were enhanced during pain condition comparatively to the three control conditions. This increase did not statistically differ across VF conditions (congruent or incongruent. Interestingly however, the types of sensations evoked by the conflict in the presence of pain (changes in intensity of pain or discomfort, changes in temperature or impression of a missing limb were different than those evoked by the conflict alone (loss of control, peculiarity and the perception of having an extra limb. Finally, results showed no relationship between the amount of motor and sensory

McMaster-Toronto Arthritis Patient Preference Disability Questionnaire sensitivity to change in low back pain: influence of shifts in priorities.

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Katherine Sanchez

Full Text Available OBJECTIVE: To assess the sensitivity to change of the McMaster Toronto Arthritis Patient Preference Disability Questionnaire (MACTAR in chronic low back pain (CLBP and shifts in patients' priorities of disabling activities over time. METHODS: A prospective longitudinal survey of 100 patients (38 males with CLBP in a tertiary care teaching hospital. Evaluation at baseline and 6 months by the MACTAR, Quebec Back Pain Disability Questionnaire (QUEBEC, Hospital Anxiety and Depression scale (HAD, Fear-Avoidance Beliefs Questionnaire (FABQ, Coping Strategies Questionnaire (CSQ, and pain and handicap visual analogue scales (VASs. Patients' perceived improvement or worsening of condition was assessed at 6 months. Effect size (ES and Standardized response mean (SRM and effect size (ES were used to evaluate sensitivity to change of the MACTAR. RESULTS: The MACTAR SRM and ES values (SRM = 0.25; ES = 0.37 were among the highest for the instruments evaluated. For patients considering their condition as improved, the SRM was 0.66 and the ES 1. The 3 disability domains, classified by the International Classification of Functioning, Disability and Health (ICF, most often cited as priorities at baseline remained the most cited at follow-up: mobility (40.9% of patients; community, social and civic life (22.7%; and domestic life (22.4%. At 6 months, 48 patients shifted their priorities, for a decrease in MACTAR SRM and ES values for patients considering their condition improved and an increase in these values for those considering their condition deteriorated. CONCLUSIONS: Although the MACTAR has similar sensitivity to change as other outcome measures widely used in CLBP, shifts in patient priorities over time are common and influence scores and sensitivity to change.

Wen-Luo-Tong Prevents Glial Activation and Nociceptive Sensitization in a Rat Model of Oxaliplatin-Induced Neuropathic Pain.

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Deng, Bo; Jia, Liqun; Pan, Lin; Song, Aiping; Wang, Yuanyuan; Tan, Huangying; Xiang, Qing; Yu, Lili; Ke, Dandan

2016-01-01

One of the main dose-limiting complications of the chemotherapeutic agent oxaliplatin (OXL) is painful neuropathy. Glial activation and nociceptive sensitization may be responsible for the mechanism of neuropathic pain. The Traditional Chinese Medicine (TCM) Wen-luo-tong (WLT) has been widely used in China to treat chemotherapy induced neuropathic pain. However, there is no study on the effects of WLT on spinal glial activation induced by OXL. In this study, a rat model of OXL-induced chronic neuropathic pain was established and WLT was administrated. Pain behavioral tests and morphometric examination of dorsal root ganglia (DRG) were conducted. Glial fibrillary acidic protein (GFAP) immunostaining was performed, glial activation was evaluated, and the excitatory neurotransmitter substance P (SP) and glial-derived proinflammatory cytokine tumor necrosis factor-α (TNF-α) were analyzed. WLT treatment alleviated OXL-induced mechanical allodynia and mechanical hyperalgesia. Changes in the somatic, nuclear, and nucleolar areas of neurons in DRG were prevented. In the spinal dorsal horn, hypertrophy and activation of GFAP-positive astrocytes were averted, and the level of GFAP mRNA decreased significantly. Additionally, TNF-α mRNA and protein levels decreased. Collectively, these results indicate that WLT reversed both glial activation in the spinal dorsal horn and nociceptive sensitization during OXL-induced chronic neuropathic pain in rats.

Neonatal pain

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Walker, Suellen M

2014-01-01

Effective management of procedural and postoperative pain in neonates is required to minimize acute physiological and behavioral distress and may also improve acute and long-term outcomes. Painful stimuli activate nociceptive pathways, from the periphery to the cortex, in neonates and behavioral responses form the basis for validated pain assessment tools. However, there is an increasing awareness of the need to not only reduce acute behavioral responses to pain in neonates, but also to protect the developing nervous system from persistent sensitization of pain pathways and potential damaging effects of altered neural activity on central nervous system development. Analgesic requirements are influenced by age-related changes in both pharmacokinetic and pharmacodynamic response, and increasing data are available to guide safe and effective dosing with opioids and paracetamol. Regional analgesic techniques provide effective perioperative analgesia, but higher complication rates in neonates emphasize the importance of monitoring and choice of the most appropriate drug and dose. There have been significant improvements in the understanding and management of neonatal pain, but additional research evidence will further reduce the need to extrapolate data from older age groups. Translation into improved clinical care will continue to depend on an integrated approach to implementation that encompasses assessment and titration against individual response, education and training, and audit and feedback. PMID:24330444

Frequent mild head injury promotes trigeminal sensitivity concomitant with microglial proliferation, astrocytosis, and increased neuropeptide levels in the trigeminal pain system.

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Tyburski, Ashley L; Cheng, Lan; Assari, Soroush; Darvish, Kurosh; Elliott, Melanie B

2017-12-01

Frequent mild head injuries or concussion along with the presence of headache may contribute to the persistence of concussion symptoms. In this study, the acute effects of recovery between mild head injuries and the frequency of injuries on a headache behavior, trigeminal allodynia, was assessed using von Frey testing up to one week after injury, while histopathological changes in the trigeminal pain pathway were evaluated using western blot, ELISA and immunohistochemistry.  RESULTS: A decreased recovery time combined with an increased mild closed head injury (CHI) frequency results in reduced trigeminal allodynia thresholds compared to controls. The repetitive CHI group with the highest injury frequency showed the greatest reduction in trigeminal thresholds along with greatest increased levels of calcitonin gene-related peptide (CGRP) in the trigeminal nucleus caudalis. Repetitive CHI resulted in astrogliosis in the central trigeminal system, increased GFAP protein levels in the sensory barrel cortex, and an increased number of microglia cells in the trigeminal nucleus caudalis. Headache behavior in rats is dependent on the injury frequency and recovery interval between mild head injuries. A worsening of headache behavior after repetitive mild head injuries was concomitant with increases in CGRP levels, the presence of astrocytosis, and microglia proliferation in the central trigeminal pathway. Signaling between neurons and proliferating microglia in the trigeminal pain system may contribute to the initiation of acute headache after concussion or other traumatic brain injuries.

Anxiety sensitivity as a predictor of anxiety and pain related to third molar removal

NARCIS (Netherlands)

van Wijk, Arjen J.; de Jongh, Ad; Lindeboom, Jerome A.

2010-01-01

Anxiety sensitivity (AS) refers to the fear of anxiety-related symptoms resulting from beliefs that such sensations have negative somatic, social, or psychological consequences. The aim of the present study was to investigate whether AS can predict both anticipated and experienced pain and state and

Anxiety sensitivity as a predictor of anxiety and pain related to third molar removal

NARCIS (Netherlands)

van Wijk, A.J.; de Jongh, A.; Lindeboom, J.A.

2010-01-01

PURPOSE: Anxiety sensitivity (AS) refers to the fear of anxiety-related symptoms resulting from beliefs that such sensations have negative somatic, social, or psychological consequences. The aim of the present study was to investigate whether AS can predict both anticipated and experienced pain and

Habituation and sensitization in primary headaches

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2013-01-01

The phenomena of habituation and sensitization are considered most useful for studying the neuronal substrates of information processing in the CNS. Both were studied in primary headaches, that are functional disorders of the brain characterized by an abnormal responsivity to any kind of incoming innocuous or painful stimuli and it’s cycling pattern over time (interictal, pre-ictal, ictal). The present review summarizes available data on stimulus responsivity in primary headaches obtained with clinical neurophysiology. In migraine, the majority of electrophysiological studies between attacks have shown that, for a number of different sensory modalities, the brain is characterised by a lack of habituation of evoked responses to repeated stimuli. This abnormal processing of the incoming information reaches its maximum a few days before the beginning of an attack, and normalizes during the attack, at a time when sensitization may also manifest itself. An abnormal rhythmic activity between thalamus and cortex, namely thalamocortical dysrhythmia, may be the pathophysiological mechanism subtending abnormal information processing in migraine. In tension-type headache (TTH), only few signs of deficient habituation were observed only in subgroups of patients. By contrast, using grand-average responses indirect evidence for sensitization has been found in chronic TTH with increased nociceptive specific reflexes and evoked potentials. Generalized increased sensitivity to pain (lower thresholds and increased pain rating) and a dysfunction in supraspinal descending pain control systems may contribute to the development and/or maintenance of central sensitization in chronic TTH. Cluster headache patients are chrarcterized during the bout and on the headache side by a pronounced lack of habituation of the brainstem blink reflex and a general sensitization of pain processing. A better insight into the nature of these ictal/interictal electrophysiological dysfunctions in primary

Mechanical pain sensitivity of deep tissues in children - possible development of myofascial trigger points in children

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Han Ting-I

2012-02-01

Full Text Available Abstract Background It is still unclear when latent myofascial trigger points (MTrPs develop during early life. This study is designed to investigate the mechanical pain sensitivity of deep tissues in children in order to see the possible timing of the development of latent MTrPs and attachment trigger points (A-TrPs in school children. Methods Five hundreds and five healthy school children (age 4- 11 years were investigated. A pressure algometer was used to measure the pressure pain threshold (PPT at three different sites in the brachioradialis muscle: the lateral epicondyle at elbow (site A, assumed to be the A-TrP site, the mid-point of the muscle belly (site B, assumed to be the MTrP site, and the muscle-tendon junction as a control site (site C. Results The results showed that, for all children in this study, the mean PPT values was significantly lower (p p Conclusions It is concluded that a child had increased sensitivity at the tendon attachment site and the muscle belly (endplate zone after age of 4 years. Therefore, it is likely that a child may develop an A-Trp and a latent MTrP at the brachioradialis muscle after the age of 4 years. The changes in sensitivity, or the development for these trigger points, may not be related to the activity level of children aged 7-11 years. Further investigation is still required to indentify the exact timing of the initial occurrence of a-Trps and latent MTrPs.

Neuro Emotional Technique for the treatment of trigger point sensitivity in chronic neck pain sufferers: a controlled clinical trial.

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Bablis, Peter; Pollard, Henry; Bonello, Rod

2008-05-21

Trigger points have been shown to be active in many myofascial pain syndromes. Treatment of trigger point pain and dysfunction may be explained through the mechanisms of central and peripheral paradigms. This study aimed to investigate whether the mind/body treatment of Neuro Emotional Technique (NET) could significantly relieve pain sensitivity of trigger points presenting in a cohort of chronic neck pain sufferers. Sixty participants presenting to a private chiropractic clinic with chronic cervical pain as their primary complaint were sequentially allocated into treatment and control groups. Participants in the treatment group received a short course of Neuro Emotional Technique that consists of muscle testing, general semantics and Traditional Chinese Medicine. The control group received a sham NET protocol. Outcome measurements included pain assessment utilizing a visual analog scale and a pressure gauge algometer. Pain sensitivity was measured at four trigger point locations: suboccipital region (S); levator scapulae region (LS); sternocleidomastoid region (SCM) and temporomandibular region (TMJ). For each outcome measurement and each trigger point, we calculated the change in measurement between pre- and post- treatment. We then examined the relationships between these measurement changes and six independent variables (i.e. treatment group and the above five additional participant variables) using forward stepwise General Linear Model. The visual analog scale (0 to 10) had an improvement of 7.6 at S, 7.2 at LS, 7.5 at SCM and 7.1 at the TMJ in the treatment group compared with no improvement of at S, and an improvement of 0.04 at LS, 0.1 at SCM and 0.1 at the TMJ point in the control group, (P algometer recordings of four trigger point locations in a cohort of chronic neck pain sufferers were significantly improved when compared to a control group which received a sham protocol of NET. Chronic neck pain sufferers may benefit from NET treatment in the relief

Potential neurobiological benefits of exercise in chronic pain and posttraumatic stress disorder: Pilot study.

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Scioli-Salter, Erica; Forman, Daniel E; Otis, John D; Tun, Carlos; Allsup, Kelly; Marx, Christine E; Hauger, Richard L; Shipherd, Jillian C; Higgins, Diana; Tyzik, Anna; Rasmusson, Ann M

2016-01-01

This pilot study assessed the effects of cardiopulmonary exercise testing and cardiorespiratory fitness on plasma neuropeptide Y (NPY), allopregnanolone and pregnanolone (ALLO), cortisol, and dehydroepiandrosterone (DHEA), and their association with pain sensitivity. Medication-free trauma-exposed participants were either healthy (n = 7) or experiencing comorbid chronic pain/posttraumatic stress disorder (PTSD) (n = 5). Peak oxygen consumption (VO2) during exercise testing was used to characterize cardiorespiratory fitness. Peak VO2 correlated with baseline and peak NPY levels (r = 0.66, p exercise-induced changes in ALLO (r = 0.89, p exercise correlated with pain threshold 30 min after exercise (r = 0.65, p exercise-induced increases in ALLO correlated with pain tolerance 30 min after exercise (r = 0.64, p exercise-induced changes in cortisol and DHEA levels were inversely correlated with pain tolerance after exercise (r = -0.69, p exercise, which in turn relate to pain sensitivity. Future work will examine whether progressive exercise training increases cardiorespiratory fitness in association with increases in NPY and ALLO and reductions in pain sensitivity in chronic pain patients with PTSD.

Increased skeletal muscle capillarization enhances insulin sensitivity

DEFF Research Database (Denmark)

Åkerström, Thorbjörn; Laub, Lasse; Vedel, Kenneth

2014-01-01

Increased skeletal muscle capillarization is associated with improved glucose tolerance and insulin sensitivity. However, a possible causal relationship has not previously been identified. We therefore investigated whether increased skeletal muscle capillarization increases insulin sensitivity....... Skeletal muscle specific angiogenesis was induced by adding the α1-adrenergic receptor antagonist Prazosin to the drinking water of Sprague Dawley rats (n=33) while 34 rats served as controls. Insulin sensitivity was measured ≥40 h after termination of the 3-week Prazosin treatment, which ensured...... that Prazosin was cleared from the blood stream. Whole-body insulin sensitivity was measured in conscious, unrestrained rats by hyperinsulinemic euglycemic clamp. Tissue specific insulin sensitivity was assessed by administration of 2-deoxy-[(3)H]-Glucose during the plateau phase of the clamp. Whole...

Is heat pain detection threshold associated with the area of secondary hyperalgesia following brief thermal sensitization? A study of healthy volunteers - design and detailed plan of analysis.

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Hansen, Morten Sejer; Wetterslev, Jørn; Pipper, Christian Bressen; Asghar, Mohammad Sohail; Dahl, Jørgen Berg

2016-05-31

Several factors are believed to influence the development and experience of pain. Human clinical pain models are central tools, in the investigation of basic physiologic pain responses, and can be applied in patients as well as in healthy volunteers. Each clinical pain model investigates different aspects of the human pain response. Brief thermal sensitization induces a mild burn injury, resulting in development of primary hyperalgesia at the site of stimulation, and secondary hyperalgesia surrounding the site of stimulation. Central sensitization is believed to play an important role in the development of secondary hyperalgesia; however, a possible association of secondary hyperalgesia following brief thermal sensitization and other heat pain models remains unknown. Our aim with this study is to investigate how close the heat pain detection threshold is associated with the size of the area of secondary hyperalgesia induced by the clinical heat pain model: Brief thermal sensitization. We aim to include 120 healthy participants. The participants will be tested on two separate study days with the following procedures: i) Brief thermal sensitization, ii) heat pain detection threshold and iii) pain during thermal stimulation. Additionally, the participants will be tested with the Pain Catastrophizing Scale and Hospital Anxiety and Depression Scale questionnaires. We conducted statistical simulations based on data from our previous study, to estimate an empirical power of 99.9 % with α of 0.05. We define that an R(2) heat stimulation, and thus may be a biomarker of an individual's pain sensitivity. The number of studies investigating secondary hyperalgesia is growing; however basic knowledge of the physiologic aspects of secondary hyperalgesia in humans is still incomplete. We therefore find it interesting to investigate if HPDT, a known quantitative sensory test, is associated with areas of secondary hyperalgesia following brief thermal sensitization Clinicaltrials

Role of microglia in neuropathic pain, postoperative pain, and morphine tolerance

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Wen, Yeong-Ray; Tan, Ping-Heng; Cheng, Jen-Kun; Liu, Yen-Chin; Ji, Ru-Rong

2011-01-01

Management of chronic pain such as nerve injury-induced neuropathic pain associated with diabetic neuropathy, viral infection, and cancer is a real clinical challenge. Major surgeries such as breast and thoracic surgery, leg amputation, and coronary artery bypass surgery also lead to chronic pain in 10–50% of individuals after acute postoperative pain, in part due to surgery-induced nerve injury. Current treatments mainly focus on blocking neurotransmission in the pain pathway and have only resulted in limited success. Ironically, chronic opioid exposure may lead to paradoxical pain. Development of effective therapeutic strategies requires a better understanding of cellular mechanisms underlying the pathogenesis of neuropathic pain. An important progress in pain research points to important role of microglial cells in the development of chronic pain. Spinal cord microglia are strongly activated after nerve injury, surgical incision, and chronic opioid exposure. Increasing evidence suggests that under all these conditions the activated microglia not only exhibit increased expression of microglial markers CD11b and Iba1 but also display elevated phosphorylation of p38 MAP kinase. Inhibition of spinal cord p38 has been shown to attenuate neuropathic pain and postoperative pain, as well as morphine-induced antinociceptive tolerance. Activation of p38 in spinal microglia results in increased synthesis and release of the neurotrophin BDNF and the proinflammatory cytokines IL-1β, IL-6, and TNF-α. These microglia-released mediators can powerfully modulate spinal cord synaptic transmission, leading to increased excitability of dorsal horn neurons, i.e. central sensitization, in part via suppressing inhibitory synaptic transmission. We review the studies that support the pronociceptive role of microglia in conditions of neuropathic pain, post-surgical pain, and opioid tolerance. Some of these studies have been accomplished by four Taiwanese anesthesiologists who are also

Do Australian Football players have sensitive groins? Players with current groin pain exhibit mechanical hyperalgesia of the adductor tendon.

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Drew, Michael K; Lovell, Gregory; Palsson, Thorvaldur S; Chiarelli, Pauline E; Osmotherly, Peter G

2016-10-01

This is the first study to evaluate the mechanical sensitivity, clinical classifications and prevalence of groin pain in Australian football players. Case-control. Professional (n=66) and semi-professional (n=9) Australian football players with and without current or previous groin injuries were recruited. Diagnoses were mapped to the Doha Agreement taxonomy. Point and career prevalence of groin pain was calculated. Pressure pain thresholds (PPTs) were assessed at regional and distant sites using handheld pressure algometry across four sites bilaterally (adductor longus tendon, pubic bone, rectus femoris, tibialis anterior muscle). To assess the relationship between current groin pain and fixed effects of hyperalgesia of each site and a history of groin pain, a mixed-effect logistic regression model was utilised. Receiver Operator Characteristic (ROC) curve were determined for the model. Point prevalence of groin pain in the preseason was 21.9% with a career prevalence of 44.8%. Adductor-related groin pain was the most prevalent classification in the pre-season period. Hyperalgesia was observed in the adductor longus tendon site in athletes with current groin pain (OR=16.27, 95% CI 1.86 to 142.02). The ROC area under the curve of the regression model was fair (AUC=0.76, 95% CI 0.54 to 0.83). Prevalence data indicates that groin pain is a larger issue than published incidence rates imply. Adductor-related groin pain is the most common diagnosis in pre-season in this population. This study has shown that hyperalgesia exists in Australian football players experiencing groin pain indicating the value of assessing mechanical pain sensitivity as a component of the clinical assessment. Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Pain sensitivity and neural processing during dissociative states in patients with borderline personality disorder with and without comorbid posttraumatic stress disorder: a pilot study.

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Ludäscher, Petra; Valerius, Gabriele; Stiglmayr, Christian; Mauchnik, Jana; Lanius, Ruth A; Bohus, Martin; Schmahl, Christian

2010-05-01

Stress-induced dissociative states involving analgesia are a common feature of borderline personality disorder (BPD) and posttraumatic stress disorder (PTSD). Our aim was to investigate the psychologic, somatosensory (pain sensitivity) and neural correlates of dissociative states in patients with these disorders. We included 15 women with BPD who were not taking medication; 10 of these women had comorbid PTSD. While undergoing functional magnetic resonance imaging at 1.5 Tesla, participants were exposed to a script describing a personalized dissociation-inducing situation and a personalized script describing a neutral situation. We assessed dissociative psychopathology and pain sensitivity. Dissociative psychopathology scores were significantly higher and pain sensitivity was lower after the dissociation-inducing script was read compared with the neutral script. The blood oxygen level-dependent (BOLD) signal was significantly increased in the left inferior frontal gyrus (Brodmann area [BA] 9) during the presentation of the dissociation-inducing script. Regression analyses revealed positive correlations between BOLD signal and dissociative psychopathology in the left superior frontal gyrus (BA 6) and negative correlations in the right middle (BA 21) and inferior temporal gyrus (BA 20). In the subgroup of participants with comorbid PTSD, we also found increased activity in the left cingulate gyrus (BA 32) during script-driven imagery-induced dissociation, a positive correlation between dissociation scores and activity in the right and left insula (BA 13) and a negative correlation in the right parahippocampal gyrus (BA 35). The main limitation of this pilot study is the absence of a control group. Therefore, the results may also reflect the neural correlates of non-BPD/PTSD specific dissociative states or the neural correlates of emotionally stressful or "loaded" memories. Another limitation is the uncorrected statistical level of the functional magnetic resonance

Increased neural responses to empathy for pain might explain how acute stress increases prosociality.

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Tomova, L; Majdandžic, J; Hummer, A; Windischberger, C; Heinrichs, M; Lamm, C

2017-03-01

Recent behavioral investigations suggest that acute stress can increase prosocial behavior. Here, we investigated whether increased empathy represents a potential mechanism for this finding. Using functional magnetic resonance imaging, we assessed the effects of acute stress on neural responses related to automatic and regulatory components of empathy for pain as well as subsequent prosocial behavior. Stress increased activation in brain areas associated with the automatic sharing of others' pain, such as the anterior insula, the anterior midcingulate cortex, and the primary somatosensory cortex. In addition, we found increased prosocial behavior under stress. Furthermore, activation in the anterior midcingulate cortex mediated the effects of stress on prosocial behavior. However, stressed participants also displayed stronger and inappropriate other-related responses in situations which required them to take the perspective of another person, and to regulate their automatic affective responses. Thus, while acute stress may increase prosocial behavior by intensifying the sharing of others' emotions, this comes at the cost of reduced cognitive appraisal abilities. Depending on the contextual constraints, stress may therefore affect empathy in ways that are either beneficial or detrimental. © The Author (2016). Published by Oxford University Press.

Pain relief by touch: a quantitative approach.

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Mancini, Flavia; Nash, Thomas; Iannetti, Gian Domenico; Haggard, Patrick

2014-03-01

Pain relief by touch has been studied for decades in pain neuroscience. Human perceptual studies revealed analgesic effects of segmental tactile stimulation, as compared to extrasegmental touch. However, the spatial organisation of touch-pain interactions within a single human dermatome has not been investigated yet. In 2 experiments we tested whether, how, and where within a dermatome touch modulates the perception of laser-evoked pain. We measured pain perception using intensity ratings, qualitative descriptors, and signal detection measures of sensitivity and response bias. Touch concurrent with laser pulses produced a significant analgesia, and reduced the sensitivity in detecting the energy of laser stimulation, implying a functional loss of information within the ascending Aδ pathway. Touch also produced a bias to judge laser stimuli as less painful. This bias decreased linearly when the distance between the laser and tactile stimuli increased. Thus, our study provides evidence for a spatial organisation of intrasegmental touch-pain interactions. Copyright © 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Increased neural responses to empathy for pain might explain how acute stress increases prosociality

OpenAIRE

Tomova, L.; Majdand?i?, J.; Hummer, A.; Windischberger, C.; Heinrichs, M.; Lamm, C.

2016-01-01

Abstract Recent behavioral investigations suggest that acute stress can increase prosocial behavior. Here, we investigated whether increased empathy represents a potential mechanism for this finding. Using functional magnetic resonance imaging, we assessed the effects of acute stress on neural responses related to automatic and regulatory components of empathy for pain as well as subsequent prosocial behavior. Stress increased activation in brain areas associated with the automatic sharing of...

Predicting postoperative pain by preoperative pressure pain assessment.

Science.gov (United States)

Hsu, Yung-Wei; Somma, Jacques; Hung, Yu-Chun; Tsai, Pei-Shan; Yang, Chen-Hsien; Chen, Chien-Chuan

2005-09-01

The goal of this study was to evaluate whether preoperative pressure pain sensitivity testing is predictive of postoperative surgical pain. Female subjects undergoing lower abdominal gynecologic surgery were studied. A pressure algometer was used preoperatively to determine the pressure pain threshold and tolerance. A visual analog scale (VAS) was used to assess postoperative pain. A State-Trait Anxiety Inventory was used to assess patients' anxiety. Subjects received intravenous patient-controlled analgesia for postoperative pain control. The preoperative pain threshold and tolerance were compared with the postoperative VAS pain score and morphine consumption. Forty women were enrolled. Their preoperative pressure pain threshold and tolerance were 141 +/- 65 kPa and 223 +/- 62 kPa, respectively. The VAS pain score in the postanesthesia care unit and at 24 h postoperatively were 81 +/- 24 and 31 +/- 10, respectively. Highly anxious patients had higher VAS pain scores in the postanesthesia care unit (P pain tolerance was significantly correlated with the VAS at 24 h postoperatively (P pain tolerance after fentanyl administration (mean, 272 +/- 68 kPa) correlated significantly with morphine consumption in the first 24 h postoperatively (P pain tolerance is significantly correlated with the level of postoperative pain. Pain tolerance assessment after fentanyl was administered and fentanyl sensitivity predicted the dose of analgesics used in the first 24 h after surgery. The algometer is thus a simple, useful tool for predicting postoperative pain and analgesic consumption.

Stress-Induced Chronic Visceral Pain of Gastrointestinal Origin

Directory of Open Access Journals (Sweden)

Beverley Greenwood-Van Meerveld

2017-11-01

Full Text Available Visceral pain is generally poorly localized and characterized by hypersensitivity to a stimulus such as organ distension. In concert with chronic visceral pain, there is a high comorbidity with stress-related psychiatric disorders including anxiety and depression. The mechanisms linking visceral pain with these overlapping comorbidities remain to be elucidated. Evidence suggests that long term stress facilitates pain perception and sensitizes pain pathways, leading to a feed-forward cycle promoting chronic visceral pain disorders such as irritable bowel syndrome (IBS. Early life stress (ELS is a risk-factor for the development of IBS, however the mechanisms responsible for the persistent effects of ELS on visceral perception in adulthood remain incompletely understood. In rodent models, stress in adult animals induced by restraint and water avoidance has been employed to investigate the mechanisms of stress-induce pain. ELS models such as maternal separation, limited nesting, or odor-shock conditioning, which attempt to model early childhood experiences such as neglect, poverty, or an abusive caregiver, can produce chronic, sexually dimorphic increases in visceral sensitivity in adulthood. Chronic visceral pain is a classic example of gene × environment interaction which results from maladaptive changes in neuronal circuitry leading to neuroplasticity and aberrant neuronal activity-induced signaling. One potential mechanism underlying the persistent effects of stress on visceral sensitivity could be epigenetic modulation of gene expression. While there are relatively few studies examining epigenetically mediated mechanisms involved in visceral nociception, stress-induced visceral pain has been linked to alterations in DNA methylation and histone acetylation patterns within the brain, leading to increased expression of pro-nociceptive neurotransmitters. This review will discuss the potential neuronal pathways and mechanisms responsible for

Stress-Induced Chronic Visceral Pain of Gastrointestinal Origin

Science.gov (United States)

Greenwood-Van Meerveld, Beverley; Johnson, Anthony C.

2017-01-01

Visceral pain is generally poorly localized and characterized by hypersensitivity to a stimulus such as organ distension. In concert with chronic visceral pain, there is a high comorbidity with stress-related psychiatric disorders including anxiety and depression. The mechanisms linking visceral pain with these overlapping comorbidities remain to be elucidated. Evidence suggests that long term stress facilitates pain perception and sensitizes pain pathways, leading to a feed-forward cycle promoting chronic visceral pain disorders such as irritable bowel syndrome (IBS). Early life stress (ELS) is a risk-factor for the development of IBS, however the mechanisms responsible for the persistent effects of ELS on visceral perception in adulthood remain incompletely understood. In rodent models, stress in adult animals induced by restraint and water avoidance has been employed to investigate the mechanisms of stress-induce pain. ELS models such as maternal separation, limited nesting, or odor-shock conditioning, which attempt to model early childhood experiences such as neglect, poverty, or an abusive caregiver, can produce chronic, sexually dimorphic increases in visceral sensitivity in adulthood. Chronic visceral pain is a classic example of gene × environment interaction which results from maladaptive changes in neuronal circuitry leading to neuroplasticity and aberrant neuronal activity-induced signaling. One potential mechanism underlying the persistent effects of stress on visceral sensitivity could be epigenetic modulation of gene expression. While there are relatively few studies examining epigenetically mediated mechanisms involved in visceral nociception, stress-induced visceral pain has been linked to alterations in DNA methylation and histone acetylation patterns within the brain, leading to increased expression of pro-nociceptive neurotransmitters. This review will discuss the potential neuronal pathways and mechanisms responsible for stress

Neuro Emotional Technique for the treatment of trigger point sensitivity in chronic neck pain sufferers: A controlled clinical trial

Directory of Open Access Journals (Sweden)

Pollard Henry

2008-05-01

Full Text Available Abstract Background Trigger points have been shown to be active in many myofascial pain syndromes. Treatment of trigger point pain and dysfunction may be explained through the mechanisms of central and peripheral paradigms. This study aimed to investigate whether the mind/body treatment of Neuro Emotional Technique (NET could significantly relieve pain sensitivity of trigger points presenting in a cohort of chronic neck pain sufferers. Methods Sixty participants presenting to a private chiropractic clinic with chronic cervical pain as their primary complaint were sequentially allocated into treatment and control groups. Participants in the treatment group received a short course of Neuro Emotional Technique that consists of muscle testing, general semantics and Traditional Chinese Medicine. The control group received a sham NET protocol. Outcome measurements included pain assessment utilizing a visual analog scale and a pressure gauge algometer. Pain sensitivity was measured at four trigger point locations: suboccipital region (S; levator scapulae region (LS; sternocleidomastoid region (SCM and temporomandibular region (TMJ. For each outcome measurement and each trigger point, we calculated the change in measurement between pre- and post- treatment. We then examined the relationships between these measurement changes and six independent variables (i.e. treatment group and the above five additional participant variables using forward stepwise General Linear Model. Results The visual analog scale (0 to 10 had an improvement of 7.6 at S, 7.2 at LS, 7.5 at SCM and 7.1 at the TMJ in the treatment group compared with no improvement of at S, and an improvement of 0.04 at LS, 0.1 at SCM and 0.1 at the TMJ point in the control group, (P Conclusion After a short course of NET treatment, measurements of visual analog scale and pressure algometer recordings of four trigger point locations in a cohort of chronic neck pain sufferers were significantly

The Modulation of Pain by Circadian and Sleep-Dependent Processes: A Review of the Experimental Evidence

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Hagenauer, Megan; Crodelle, Jennifer; Piltz, Sofia Helena

2017-01-01

conditions, pain sensitivity varies across the 24 h day, with highest sensitivity occurring during the evening in humans. Pain sensitivity is also modulated by sleep behavior, with pain sensitivity increasing in response to the build-up of homeostatic sleep pressure following sleep deprivation or sleep...... of physiologically meaningful stimulation levels. Following this normalization, we find that the estimated impact of the daily rhythm and of sleep deprivation on experimental pain measurements is surprisingly consistent across different pain modalities. We also review evidence documenting the impact of circadian...... rhythms and sleep deprivation on the neural circuitry in the spinal cord underlying pain sensation. The characterization of sleep-dependent and circadian influences on pain sensitivity in this review paper is used to develop and constrain the mathematical models introduced in the two companion articles....

Hypersensitivity to pain in congenital blindness

DEFF Research Database (Denmark)

Slimani, Hocine; Danti, Sabrina; Ricciardi, Emiliano

2013-01-01

Vision is important for avoiding encounters with objects in the environment that may imperil physical integrity. We tested whether, in the absence of vision, a lower pain threshold would arise from an adaptive shift to other sensory channels. We therefore measured heat and cold pain thresholds an...... that blind subjects are more attentive to signals of external threats. These findings indicate that the absence of vision from birth induces a hypersensitivity to painful stimuli, lending new support to a model of sensory integration of vision and pain processing......., congenitally blind subjects have lower heat pain thresholds, rate suprathreshold heat pain stimuli as more painful, and have increased sensitivity for cold pain stimuli. Thresholds for nonpainful thermal stimulation did not differ between groups. The results of the pain questionnaires further indicated...

The Effect of Daily Self-Measurement of Pressure Pain Sensitivity Followed by Acupressure on Depression and Quality of Life versus Treatment as Usual in Ischemic Heart Disease

DEFF Research Database (Denmark)

Bergmann, Natasha; Ballegaard, Søren; Bech, Per

2014-01-01

-measurement of PPS twice daily followed by acupressure as mandatory action, aiming at a reduction in PPS. Primary endpoint: change in depressive symptoms as measured by Major depression inventory (MDI). Other endpoints: changes in PPS, Well-being (WHO-5) and mental and physical QOL (SF-36). RESULTS: At 3 months PPS......BACKGROUND: Depressive symptoms and reduced quality of life (QOL) are parts of the chronic stress syndrome and predictive of adverse outcome in patients with ischemic heart disease (IHD). Chronic stress is associated with increased sensitivity for pain, which can be measured by algometry...... as Pressure Pain Sensitivity (PPS) on the sternum. AIM: To evaluate if stress focus by self-measurement of PPS, followed by stress reducing actions including acupressure, can decrease depressive symptoms and increase psychological well-being in people with stable IHD. DESIGN: Observer blinded randomized...

Knee arthritis pain is reduced and range of motion is increased following moderate pressure massage therapy.

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Field, Tiffany; Diego, Miguel; Gonzalez, Gladys; Funk, C G

2015-11-01

The literature on massage therapy effects on knee pain suggests that pain was reduced based on self-report, but little is known about range of motion (ROM) effects. Medical School staff and faculty who had knee arthritis pain were randomly assigned to a moderate pressure massage therapy or a waitlist control group (24 per group). Self-reports included the WOMAC (pain, stiffness and function) and the Pittsburgh Sleep Quality Index. ROM and ROM-related pain were assessed before and after the last sessions. The massage group showed an immediate post-massage increase in ROM and a decrease in ROM-associated pain. On the last versus the first day of the study, the massage group showed greater increases in ROM and decreases in ROM-related pain as well as less self-reported pain and sleep disturbances than the waitlist control group. These data highlight the effectiveness of moderate pressure massage therapy for increasing ROM and lessening ROM-related pain and long-term pain and sleep disturbances. Copyright © 2015 Elsevier Ltd. All rights reserved.

Short-term sleep disturbance-induced stress does not affect basal pain perception, but does delay postsurgical pain recovery

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Wang, Po-Kai; Cao, Jing; Wang, Hongzhen; Liang, Lingli; Zhang, Jun; Lutz, Brianna Marie; Shieh, Kun-Ruey; Bekker, Alex; Tao, Yuan-Xiang

2015-01-01

Chronic sleep disturbance-induced stress is known to increase basal pain sensitivity. However, most surgical patients frequently report short-term sleep disturbance/deprivation during pre- and post-operation periods and have normal pain perception pre-surgery. Whether this short-term sleep disturbance affects postsurgical pain is elusive. We here reported that pre- or post-exposure to rapid eye movement sleep disturbance (REMSD) 6 h daily for 3 consecutive days did not alter basal responses t...

A hip abduction exercise prior to prolonged standing increased movement while reducing cocontraction and low back pain perception in those initially reporting low back pain.

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Viggiani, Daniel; Callaghan, Jack P

2016-12-01

Persons who develop low back pain from prolonged standing exhibit increased muscle cocontraction, decreased movement and increased spine extension. However, it is unclear how these factors relate to pain development. The purpose of this study was to use hip abductor fatigue to manipulate muscle activity patterns and determine its effects on standing behaviours and pain development. Forty participants stood for two hours twice, once following a hip abductor fatigue exercise (fatigue), and once without exercise beforehand (control). Trunk and gluteal muscle activity were measured to determine cocontraction. Lumbo-pelvic angles and force plates were used to assess posture and movement strategies. Visual analog scales differentiated pain (PDs) and non-pain developers (NPDs). PDs reported less low back pain during the fatigue session, with females having earlier reductions of similar scale than males. The fatigue session reduced gluteal and trunk cocontraction and increased centre of pressure movement; male and female PDs had opposing spine posture compensations. Muscle fatigue prior to standing reduced cocontraction, increased movement during standing and reduced the low back pain developed by PDs; the timing of pain reductions depended on spine postures adopted during standing. Copyright © 2016 Elsevier Ltd. All rights reserved.

Differential effects of two virtual reality interventions: distraction versus pain control.

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Loreto-Quijada, Desirée; Gutiérrez-Maldonado, José; Nieto, Rubén; Gutiérrez-Martínez, Olga; Ferrer-García, Marta; Saldaña, Carmina; Fusté-Escolano, Adela; Liutsko, Liudmila

2014-06-01

There is evidence that virtual reality (VR) pain distraction is effective at improving pain-related outcomes. However, more research is needed to investigate VR environments with other pain-related goals. The main aim of this study was to compare the differential effects of two VR environments on a set of pain-related and cognitive variables during a cold pressor experiment. One of these environments aimed to distract attention away from pain (VRD), whereas the other was designed to enhance pain control (VRC). Participants were 77 psychology students, who were randomly assigned to one of the following three conditions during the cold pressor experiment: (a) VRD, (b) VRC, or (c) Non-VR (control condition). Data were collected regarding both pain-related variables (intensity, tolerance, threshold, time perception, and pain sensitivity range) and cognitive variables (self-efficacy and catastrophizing). Results showed that in comparison with the control condition, the VRC intervention significantly increased pain tolerance, the pain sensitivity range, and the degree of time underestimation. It also increased self-efficacy in tolerating pain and led to a reduction in reported helplessness. The VRD intervention significantly increased the pain threshold and pain tolerance in comparison with the control condition, but it did not affect any of the cognitive variables. Overall, the intervention designed to enhance control seems to have a greater effect on the cognitive variables assessed. Although these results need to be replicated in further studies, the findings suggest that the VRC intervention has considerable potential in terms of increasing self-efficacy and modifying the negative thoughts that commonly accompany pain problems.

Opposite patterns of change in perception of imagined and physically induced pain over the course of repeated thermal stimulations.

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Gács, B; Szolcsányi, T; Csathó, Á

2017-08-01

Individuals frequently show habituation to repeated noxious heat. However, given the defensive function of human pain processing, it is reasonable to assume that individuals anticipate that they would become increasingly sensitive to repeated thermal pain stimuli. No previous studies have, however, been addressed to this assumption. Therefore, in the current study, we investigated how healthy human individuals imagine the intensity of repeated thermal pain stimulations, and compared this with the intensity ratings given after physically induced thermal pain trials. Healthy participants (N = 20) gave pain intensity ratings in two conditions: imagined and real thermal pain. In the real pain condition, thermal pain stimuli of two intensities (minimal and moderate pain) were delivered in four consecutive trials. The duration of the peak temperature was 20 s, and stimulation was always delivered to the same location. In each trial, participants rated the pain intensity twice, 5 and 15 s after the onset of the peak temperature. In the imagined pain condition, participants were subjected to a reference pain stimulus and then asked to imagine and rate the same sequence of stimulations as in the induced pain condition. Ratings of imagined pain and physically induced pain followed opposite courses over repeated stimulations: Ratings of imagined pain indicated sensitization, whereas ratings for physically induced pain indicated habituation. The findings were similar for minimal and moderate pain intensities. The findings suggest that, rather than habituating to pain, healthy individuals imagine that they would become increasingly sensitive to repeated thermal pain stimuli. This study identified opposite patterns of change in perception of imagined pain (sensitization) and physically induced pain (habituation). The findings show that individuals anticipate that they would become increasingly sensitive to repeated pain stimuli, which might also have clinical implications. �

Pressure pain sensitivity topographical maps reveal bilateral hyperalgesia of the hands in patients with unilateral carpal tunnel syndrome.

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Fernández-de-Las-Peñas, César; Madeleine, Pascal; Martínez-Perez, Almudena; Arendt-Nielsen, Lars; Jiménez-García, Rodrigo; Pareja, Juan A

2010-08-01

To assess topographical pressure pain sensitivity maps of the hand in patients with unilateral carpal tunnel syndrome (CTS) as compared with healthy subjects. A total of 20 women with CTS (ages 32-52 years) and 20 healthy matched women (ages 32-51 years) were recruited. Pressure pain thresholds (PPTs) were measured bilaterally over 30 locations of the palm of each hand by an assessor blinded to the subjects' conditions. Patients showed lower PPTs in both hands in all of the measurement points as compared with controls (P < 0.001 for all). PPTs were lower in those points over the proximal phalanx of the fingers and the thenar eminency as compared with those points located over the distal phalanx of the fingers (P < 0.001). CTS patients showed lower PPT levels in dermatomes C6, C7, and C8 when compared with healthy controls (P < 0.001 for all), but without differences between dermatomes (P = 0.4). PPT was negatively correlated with both hand pain intensity and duration of symptoms (P < 0.001 for all). Our findings revealed bilateral generalized pressure pain hyperalgesia in unilateral CTS because lower PPT levels were found in all of the points. The pressure pain hyperalgesia was not uniformly distributed since PPTs were lower in points over the proximal phalanx of the fingers and the thenar eminency as compared with those points located over the distal phalanx of the fingers. The decrease in PPT levels was associated with the intensity and the duration of the pain symptoms, supporting a role of both peripheral and central sensitization mechanisms in this pain condition.

Improved foot sensitivity and pain reduction in patients with peripheral neuropathy after treatment with monochromatic infrared photo energy--MIRE.

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Harkless, Lawrence B; DeLellis, Salvatore; Carnegie, Dale H; Burke, Thomas J

2006-01-01

The medical records of 2239 patients (mean age=73 years) with established peripheral neuropathy (PN) were examined to determine whether treatment with MIRE was, in fact, associated with increased foot sensitivity to the Semmes Weinstein monofilament (SWM) 5.07 and a reduction in neuropathic pain. The PN in 1395 of these patients (62%) was due to diabetes. Prior to treatment with MIRE, of the 10 tested sites (5 on each foot), 7.1+/-2.9 were insensitive to the SWM 5.07, and 2078 patients (93%) exhibited loss of protective sensation defined by Medicare as a loss of sensation at two or more sites on either foot. After treatment, the number of insensate sites on both feet decreased to 2.4+/-2.6, an improvement of 66%. Of the 2078 (93%) patients initially presenting with loss of protective sensation, 1106 (53%) no longer had loss of protective sensation after treatment (P<.0001); 1563 patients (70%) also exhibited neuropathic pain in addition to sensory impairment. Prior to treatment with MIRE, pain measured on the 11-point visual analogue scale (VAS) was 7.2+/-2.2 points, despite the use of a variety of pain-relieving therapeutic agents. After treatment with MIRE, pain was reduced by 4.8+/-2.4 points, a 67% reduction. Therefore, MIRE appears to be associated with significant clinical improvement in foot sensation and, simultaneously, a reduction in neuropathic pain in a large cohort of primarily Medicare aged, community-dwelling patients, initially diagnosed with PN. The quality of life associated with these two outcomes cannot be underappreciated.

Effects of a Worksite Supervised Adapted Physical Activity Program on Trunk Muscle Endurance, Flexibility, and Pain Sensitivity Among Vineyard Workers.

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Balaguier, Romain; Madeleine, Pascal; Rose-Dulcina, Kévin; Vuillerme, Nicolas

2017-01-01

In viticulture, the prevalence of low back pain is particularly high among vineyard workers exposed to sustained and awkward postures. One promising setting for low back pain prevention resides in the implementation of workplace physical activity. This nonrandomized pilot study aims at evaluating the effects of a worksite supervised adapted physical activity program among 17 vineyard workers volunteered to enter either an intervention group (n = 10) or a control group (n = 7).The intervention group followed a physical activity program for 8 weeks involving (1) 15 minutes of warm-up every working day and (2) two weekly 1-hour adapted physical activity sessions targeting trunk muscle endurance and flexibility. The control group was advised to continue normal physical activity. Evaluations were carried out at weeks 0, 4, 8, and 12. Physical capacity was assessed using flexibility tests for the trunk, along with trunk muscle flexor and extensor endurance tests. Finally, pain sensitivity was evaluated by assessing pressure pain thresholds over 14 anatomical locations in the low back region. For the intervention group, the endurance of the trunk extensor and flexor significantly increased from baseline to week 8 as well as the pressure pain thresholds. No change was observed for the control group over the same period. These encouraging results in combination with the high adherence rate set interesting foundations for the promotion of worksite supervised adapted physical activity and, most likely, offer a new promising approach to prevent low back pain among vineyard workers.

Prediction of pain sensitivity in healthy volunteers

DEFF Research Database (Denmark)

Ravn, Pernille; Frederiksen, R; Skovsen, AP

2012-01-01

The primary objective of the present study was to evaluate predictive parameters of the acute pain score during induction of an inflammatory heat injury.......The primary objective of the present study was to evaluate predictive parameters of the acute pain score during induction of an inflammatory heat injury....

Effects of vicarious pain on self-pain perception: investigating the role of awareness

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Terrighena, Esslin L; Lu, Ge; Yuen, Wai Ping; Lee, Tatia MC; Keuper, Kati

2017-01-01

The observation of pain in others may enhance or reduce self-pain, yet the boundary conditions and factors that determine the direction of such effects are poorly understood. The current study set out to show that visual stimulus awareness plays a crucial role in determining whether vicarious pain primarily activates behavioral defense systems that enhance pain sensitivity and stimulate withdrawal or appetitive systems that attenuate pain sensitivity and stimulate approach. We employed a mixed factorial design with the between-subject factors exposure time (subliminal vs optimal) and vicarious pain (pain vs no pain images), and the within-subject factor session (baseline vs trial) to investigate how visual awareness of vicarious pain images affects subsequent self-pain in the cold-pressor test. Self-pain tolerance, intensity and unpleasantness were evaluated in a sample of 77 healthy participants. Results revealed significant interactions of exposure time and vicarious pain in all three dependent measures. In the presence of visual awareness (optimal condition), vicarious pain compared to no-pain elicited overall enhanced self-pain sensitivity, indexed by reduced pain tolerance and enhanced ratings of pain intensity and unpleasantness. Conversely, in the absence of visual awareness (subliminal condition), vicarious pain evoked decreased self-pain intensity and unpleasantness while pain tolerance remained unaffected. These findings suggest that the activation of defense mechanisms by vicarious pain depends on relatively elaborate cognitive processes, while – strikingly – the appetitive system is activated in highly automatic manner independent from stimulus awareness. Such mechanisms may have evolved to facilitate empathic, protective approach responses toward suffering individuals, ensuring survival of the protective social group. PMID:28831270

Postamputation pain: studies on mechanisms.

Science.gov (United States)

Nikolajsen, Lone

2012-10-01

Amputation is followed by both painful and non-painful phantom phenomena in a large number of amputees. Non-painful phantom sensations rarely pose any clinical problem, but 60-80% of all amputees also experience painful sensations (i.e. phantom pain) located to the missing limb. The severity of phantom pain usually decreases with time, but severe pain persists in 5-10% of patients. Pain in the residual limb (i.e. stump pain) is another consequence of amputation. Both stump and phantom pain can be very difficult to treat. Treatment guidelines used for other neuropathic pain conditions are probably the best approximation, especially for the treatment of stump pain. The aim of the present doctoral thesis was to explore some of the mechanisms underlying pain after amputation. Ten studies were carried out (I-X). My PhD thesis from 1998 dealt with pain before the amputation and showed that preamputation pain increases the risk of phantom pain after amputation (I). A perioperative epidural blockade, however, did not reduce the incidence of pain or abnormal sensory phenomena after amputation (II, III). The importance of sensitization before amputation for the subsequent development of pain is supported by study IV, in which pressure pain thresholds obtained at the limb before amputation were inversely related to stump and phantom pain after 1 week. Afferent input from the periphery is likely to contribute to postamputation pain as sodium channels were upregulated in human neuromas (VI), although neuroma removal did not always alleviate phantom pain (V). Sensitization of neurons in the spinal cord also seems to be involved in pain after amputation as phantom pain was reduced by ketamine, an NMDA-receptor antagonist. Another NMDA-receptor antagonist, memantine, and gabapentin, a drug working by binding to the δ2α-subunit of voltage-gated calcium channels, had no effect on phantom pain (VII-IX). Supraspinal factors are also important for pain after amputation as

Operant conditioning of facial displays of pain.

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Kunz, Miriam; Rainville, Pierre; Lautenbacher, Stefan

2011-06-01

The operant model of chronic pain posits that nonverbal pain behavior, such as facial expressions, is sensitive to reinforcement, but experimental evidence supporting this assumption is sparse. The aim of the present study was to investigate in a healthy population a) whether facial pain behavior can indeed be operantly conditioned using a discriminative reinforcement schedule to increase and decrease facial pain behavior and b) to what extent these changes affect pain experience indexed by self-ratings. In the experimental group (n = 29), the participants were reinforced every time that they showed pain-indicative facial behavior (up-conditioning) or a neutral expression (down-conditioning) in response to painful heat stimulation. Once facial pain behavior was successfully up- or down-conditioned, respectively (which occurred in 72% of participants), facial pain displays and self-report ratings were assessed. In addition, a control group (n = 11) was used that was yoked to the reinforcement plans of the experimental group. During the conditioning phases, reinforcement led to significant changes in facial pain behavior in the majority of the experimental group (p .136). Fine-grained analyses of facial muscle movements revealed a similar picture. Furthermore, the decline in facial pain displays (as observed during down-conditioning) strongly predicted changes in pain ratings (R(2) = 0.329). These results suggest that a) facial pain displays are sensitive to reinforcement and b) that changes in facial pain displays can affect self-report ratings.

The periodontal pain paradox: Difficulty on pain assesment in dental patients (The periodontal pain paradox hypothesis

Directory of Open Access Journals (Sweden)

Haryono Utomo

2006-12-01

Full Text Available In daily dental practice, the majority of patients’ main complaints are related to pain. Most patients assume that all pains inside the oral cavity originated from the tooth. One particular case is thermal sensitivity; sometimes patients were being able to point the site of pain, although there is neither visible caries nor secondary caries in dental radiograph. In this case, gingival recession and dentin hypersensitivity are first to be treated to eliminate the pain. If these treatments failed, pain may misdiagnose as pulpal inflammation and lead to unnecessary root canal treatment. Study in pain during periodontal instrumentation of plaque-related periodontitis revealed that the majority of patients feel pain and discomfort during probing and scaling. It seems obvious because an inflammation, either acute or chronic is related to a lowered pain threshold. However, in contrast, in this case report, patient suffered from chronic gingivitis and thermal sensitivity experienced a relative pain-free sensation during probing and scaling. Lowered pain threshold which accompanied by a blunted pain perception upon periodontal instrumentation is proposed to be termed as the periodontal pain paradox. The objective of this study is to reveal the possibility of certain factors in periodontal inflammation which may involved in the periodontal pain paradox hypothesis. Patient with thermal hypersensitivity who was conducted probing and scaling, after the relative pain-free instrumentation, thermal hypersensitivity rapidly disappeared. Based on the successful periodontal treatment, it is concluded that chronic gingivitis may modulate periodontal pain perception which termed as periodontal pain paradox

Cognitive-emotional sensitization contributes to wind-up-like pain in phantom limb pain patients

DEFF Research Database (Denmark)

Vase, Lene; Nikolajsen, Lone; Christensen, Bente

2011-01-01

). Catastrophizing accounted for 35% of the variance in phantom limb pain (p=0.001) independently of anxiety and depression. Catastrophizing was also positively associated with wind-up-like pain in non-medicated patients (p=0.015), but not to pain thresholds. These findings suggest that cognitive-emotional...

Uncovering the influence of social skills and psychosociological factors on pain sensitivity using structural equation modeling.

Science.gov (United States)

Tanaka, Yoichi; Nishi, Yuki; Nishi, Yuki; Osumi, Michihiro; Morioka, Shu

2017-01-01

Pain is a subjective emotional experience that is influenced by psychosociological factors such as social skills, which are defined as problem-solving abilities in social interactions. This study aimed to reveal the relationships among pain, social skills, and other psychosociological factors by using structural equation modeling. A total of 101 healthy volunteers (41 men and 60 women; mean age: 36.6±12.7 years) participated in this study. To evoke participants' sense of inner pain, we showed them images of painful scenes on a PC screen and asked them to evaluate the pain intensity by using the visual analog scale (VAS). We examined the correlation between social skills and VAS, constructed a hypothetical model based on results from previous studies and the current correlational analysis results, and verified the model's fit using structural equation modeling. We found significant positive correlations between VAS and total social skills values, as well as between VAS and the "start of relationships" subscales. Structural equation modeling revealed that the values for "start of relationships" had a direct effect on VAS values (path coefficient =0.32, p social support. The results indicated that extroverted people are more sensitive to inner pain and tend to get more social support and maintain a better psychological condition.

Morphine- and buprenorphine-induced analgesia and antihyperalgesia in a human inflammatory pain model

DEFF Research Database (Denmark)

Ravn, Pernille; Secher, EL; Skram, U

2013-01-01

Opioid therapy is associated with the development of tolerance and paradoxically increased sensitivity to pain. It has been suggested that buprenorphine is associated with a higher antihyperalgesia/analgesia ratio than μ-opioid receptor agonists. The primary outcome of this study was therefore...... to investigate relative differences in antihyperalgesia and analgesia effects between morphine and buprenorphine in an inflammatory pain model in volunteers. The secondary outcome was to examine the relationship between pain sensitivity and opioid-induced effects on analgesia, antihyperalgesia, and descending...... pain modulation....

No change in rectal sensitivity after gut-directed hypnotherapy in children with functional abdominal pain or irritable bowel syndrome.

Science.gov (United States)

Vlieger, A M; van den Berg, M M; Menko-Frankenhuis, C; Bongers, M E J; Tromp, E; Benninga, M A

2010-01-01

Gut-directed hypnotherapy (HT) has recently been shown to be highly effective in treating children with functional abdominal pain (FAP) and irritable bowel syndrome (IBS). This study was conducted to determine the extent to which this treatment success is because of an improvement in rectal sensitivity. A total of 46 patients (aged 8-18 years) with FAP (n=28) or IBS (n=18) were randomized to either 12 weeks of standard medical therapy (SMT) or HT. To assess rectal sensitivity, a pressure-controlled intermittent distension protocol (barostat) was performed before and after the therapy. Rectal sensitivity scores changed in SMT patients from 15.1+/-7.3 mm Hg at baseline to 18.6+/-8.5 mm Hg after 12 weeks of treatment (P=0.09) and in HT patients from 17.0+/-9.2 mm Hg to 22.5+/-10.1 mm Hg (P=0.09). The number of patients with rectal hypersensitivity decreased from 6 of 18 to 0 of 18 in the HT group (P=0.04) vs. 6 of 20 to 4 of 20 in the SMT group (P=0.67). No relationship was established between treatment success and rectal pain thresholds. Rectal sensitivity scores at baseline were not correlated with intensity, frequency, or duration of abdominal pain. Clinical success achieved with HT cannot be explained by improvement in rectal sensitivity. Furthermore, no association could be found between rectal barostat findings and clinical symptoms in children with FAP or IBS. Further studies are necessary to shed more light on both the role of rectal sensitivity in pediatric FAP and IBS and the mechanisms by which hypnotherapy results in improvement of clinical symptoms.

Central sensitization phenomena after third molar surgery: A quantitative sensory testing study

DEFF Research Database (Denmark)

Jensen, T.S.; Norholt, S.E.; Svensson, P.

2008-01-01

Background: Surgical removal of third molars may carry a risk of developing persistent orofacial pain, and central sensitization appears to play an important role in the transition from acute to chronic pain. Aim: The aim of this study was to investigate sensitization (primarily central sensitiza......Background: Surgical removal of third molars may carry a risk of developing persistent orofacial pain, and central sensitization appears to play an important role in the transition from acute to chronic pain. Aim: The aim of this study was to investigate sensitization (primarily central...... sensitization) after orofacial trauma using quantitative sensory testing (QST). Methods: A total of 32 healthy men (16 patients and 16 age-matched control subjects) underwent a battery of quantitative tests adapted to the trigeminal area at baseline and 2, 7, and 30 days following surgical removal of a lower...... impacted third molar. Results: Central sensitization for at least one week was indicated by significantly increased pain intensity evoked by intraoral repetitive pinprick and electrical stimulation (p

Increased power spectral density in resting-state pain-related brain networks in fibromyalgia.

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Kim, Ji-Young; Kim, Seong-Ho; Seo, Jeehye; Kim, Sang-Hyon; Han, Seung Woo; Nam, Eon Jeong; Kim, Seong-Kyu; Lee, Hui Joong; Lee, Seung-Jae; Kim, Yang-Tae; Chang, Yongmin

2013-09-01

Fibromyalgia (FM), characterized by chronic widespread pain, is known to be associated with heightened responses to painful stimuli and atypical resting-state functional connectivity among pain-related regions of the brain. Previous studies of FM using resting-state functional magnetic resonance imaging (rs-fMRI) have focused on intrinsic functional connectivity, which maps the spatial distribution of temporal correlations among spontaneous low-frequency fluctuation in functional MRI (fMRI) resting-state data. In the current study, using rs-fMRI data in the frequency domain, we investigated the possible alteration of power spectral density (PSD) of low-frequency fluctuation in brain regions associated with central pain processing in patients with FM. rsfMRI data were obtained from 19 patients with FM and 20 age-matched healthy female control subjects. For each subject, the PSDs for each brain region identified from functional connectivity maps were computed for the frequency band of 0.01 to 0.25 Hz. For each group, the average PSD was determined for each brain region and a 2-sample t test was performed to determine the difference in power between the 2 groups. According to the results, patients with FM exhibited significantly increased frequency power in the primary somatosensory cortex (S1), supplementary motor area (SMA), dorsolateral prefrontal cortex, and amygdala. In patients with FM, the increase in PSD did not show an association with depression or anxiety. Therefore, our findings of atypical increased frequency power during the resting state in pain-related brain regions may implicate the enhanced resting-state baseline neural activity in several brain regions associated with pain processing in FM. Copyright © 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Sex dimorphism in a mediatory role of the posterior midcingulate cortex in the association between anxiety and pain sensitivity.

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Kisler, Lee-Bareket; Granovsky, Yelena; Sinai, Alon; Sprecher, Elliot; Shamay-Tsoory, Simone; Weissman-Fogel, Irit

2016-11-01

Behavioral studies found greater pain sensitivity in females that vanishes fully or partially when controlling for the emotional state. Furthermore, pain-related brain activation hints at the role of limbic structures in sex differences in pain processing. We aimed to investigate the role of pain-related limbic structures in mediating the relation between subjects' affective state (i.e., anxiety) and pain. Contact heat-evoked potentials (CHEPs) were recorded in 26 healthy subjects (13 males) simultaneously with innocuous (42 °C) baseline and target noxious (52 °C) series of stimuli administered to the left non-dominant volar forearm. The N2 and P2 components were analyzed, and their generators' activity was estimated using standardized low-resolution brain electromagnetic tomography. Thereafter, structural equation modeling (SEM) was applied separately for females and males, examining the mediatory role of the CHEPs' limbic structures generators [posterior midcingulate cortex (pMCC), insula, amygdala, and hippocampus] in the anxiety-pain sensitivity association. Females exhibited greater P2 amplitudes that were highly associated with larger pMCC activity (r = 0.910, p < 0.001). This correlation was also evident in males, though with less strength (r = 0.578, p = 0.039). Moreover, the P2 amplitudes were associated both in females (r = 0.645, p = 0.017) and males (r = 0.608, p = 0.028) with the activity of the amygdala\\hippocampus\\insula. SEM revealed that the relationship between state anxiety and pain ratings was only in females fully mediated via the effect of the pMCC on the P2 amplitude. These findings suggest that sexual dimorphism in anxiety-related brain activity may explain the differences found in CHEPs and the sex-related association between anxiety and pain.

Acute Hypoglycemia Induces Painful Neuropathy and the Treatment of Coenzyme Q10

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Yan Ping Zhang

2016-01-01

Full Text Available Diabetic neuropathic pain is reduced with tight glycemic control. However, strict control increases the risk of hypoglycemic episodes, which are themselves linked to painful neuropathy. This study explored the effects of hypoglycemia-related painful neuropathy. Pretreatment with coenzyme Q10 (CoQ10 was performed to explore the preventive effect of CoQ10 on hypoglycemia-related acute neuropathic pain. Two strains of mice were used and 1 unit/kg of insulin was given to induce hypoglycemia. Mechanical sensitivity of hindpaw withdrawal thresholds was measured using von Frey filaments. Blood glucose levels were clamped at normal levels by joint insulin and glucose injection to test whether insulin itself induced hypersensitivity. Results suggest that the increased mechanical sensitivity after insulin injection is related to decreased blood glucose levels. When blood glucose levels remained at a normal level by the linked administration of insulin and glucose, mice demonstrated no significant change in mechanical sensitivity. Pretreatment with CoQ10 prevented neuropathic pain and the expression of the stress factor c-Fos. These results support the concept that pain in the diabetic scenario can be the result of hypoglycemia and not insulin itself. Additionally, pretreatment with CoQ10 may be a potent preventive method for the development of neuropathic pain.

Neck arthritis pain is reduced and range of motion is increased by massage therapy.

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Field, Tiffany; Diego, Miguel; Gonzalez, Gladys; Funk, C G

2014-11-01

The literature on the effects of massage therapy on neck arthritis pain is mixed depending on the dose level, and it is also based on self-report. In the present study an attempt was made to enhance the effects of weekly massage therapy by having the participants massage themselves daily. And in addition to self-reports on pain, range of motion (ROM) and the associated ROM pain were assessed before and after the first massage session and pre-post the last session one month later. Staff and faculty members at a medical school who were eligible for the study if they had neck arthritis pain were randomly assigned to a massage or a waitlist control group (N = 24 per group). The massage group received moderate pressure massages weekly by a massage therapist plus daily self-massages. The waitlist control group received the same schedule massages one month after being control subjects. The massage group showed significant short-term reductions after the first and last day massages in self-reported pain and in ROM-associated pain as well as an increase in ROM. Comparisons between the massage group (N = 23) and the control group (N = 14) on the last versus the first day data suggested significantly different changes including increased ROM and reduced ROM-associated pain for the massage group and reduced ROM and increased ROM-associated pain for the control group. These changes occurred specifically for flexion and right and left lateral flexion motions. These data highlight the importance of designing massage therapy protocols that target the most affected neck muscle groups and then assessing range of motion and related pain before and after the massage therapy. Comparisons with other studies also suggest that moderate pressure may contribute to the massage effects, and the use of daily self-massages between sessions may sustain the effects and serve as a cost-effective therapy for individuals with neck arthritis pain. Copyright © 2014. Published by Elsevier Ltd.

Metformin increases pressure pain threshold in lean women with polycystic ovary syndrome.

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Kiałka, Marta; Milewicz, Tomasz; Sztefko, Krystyna; Rogatko, Iwona; Majewska, Renata

2016-01-01

Despite the strong preclinical rationale, there are only very few data considering the utility of metformin as a potential pain therapeutic in humans. The aim of this study was to determine the association between metformin therapy and pressure pain threshold (PPT) in lean women with polycystic ovary syndrome (PCOS). We hypothesized that metformin therapy in lean PCOS women increases PPT. Twenty-seven lean PCOS women with free androgen index phenotype >5 and 18 lean healthy controls were enrolled in the study. Fifteen of the PCOS women were randomly assigned to be treated with metformin 1,500 mg daily for 6 months. PPT and plasma β-endorphin levels were measured in all women at the beginning of the study and after 6 months of observation. We observed an increase in PPT values measured on deltoid and trapezius muscle in the PCOS with metformin group after 6 months of metformin administration (4.81±0.88 kg/cm(2), PPCOS without treatment group and in controls. We did not observe any significant changes in serum β-endorphin levels in any studied groups during the 6-month observation. We conclude that metformin therapy increases PPT in lean PCOS women, without affecting plasma β-endorphin concentration. Our results may suggest the potential role of metformin in pain therapy. We propose that larger, randomized studies on metformin impact on pain perception should be performed.

Strength and Pain Threshold Handheld Dynamometry Test Reliability in Patellofemoral Pain.

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van der Heijden, R A; Vollebregt, T; Bierma-Zeinstra, S M A; van Middelkoop, M

2015-12-01

Patellofemoral pain syndrome (PFPS), characterized by peri- and retropatellar pain, is a common disorder in young, active people. The etiology is unclear; however, quadriceps strength seems to be a contributing factor, and sensitization might play a role. The study purpose is determining the inter-rater reliability of handheld dynamometry to test both quadriceps strength and pressure pain threshold (PPT), a measure for sensitization, in patients with PFPS. This cross-sectional case-control study comprises 3 quadriceps strength and one PPT measurements performed by 2 independent investigators in 22 PFPS patients and 16 matched controls. Inter-rater reliability was analyzed using intraclass correlation coefficients (ICC) and Bland-Altman plots. Inter-rater reliability of quadriceps strength testing was fair to good in PFPS patients (ICC=0.72) and controls (ICC=0.63). Bland-Altman plots showed an increased difference between assessors when average quadriceps strength values exceeded 250 N. Inter-rater reliability of PPT was excellent in patients (ICC=0.79) and fair to good in controls (ICC=0.52). Handheld dynamometry seems to be a reliable method to test both quadriceps strength and PPT in PFPS patients. Inter-rater reliability was higher in PFPS patients compared to control subjects. With regard to quadriceps testing, a higher variance between assessors occurs when quadriceps strength increases. © Georg Thieme Verlag KG Stuttgart · New York.

The sources of pain in osteoarthritis: a pathophysiological review

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F. Salaffi

2014-06-01

Full Text Available The pain of osteoarthritis (OA has multifaceted etiologies within and outside the joint. It is believed to be driven by both nociceptive and neuropathic mechanisms, as well as abnormal excitability in the pain pathways of the peripheral and central nervous system. Inflammation in the joint triggers a cascade of events that leads to peripheral sensitization, increased sensitivity of nociceptive primary afferent neurons, and hyperexcitability of the nociceptive neurons in the central nervous system. Pain receptors have been found in the synovium, ligaments, capsule, subchondral bone and surrounding tissues, with the exception of articular cartilage. The bone-related causes of pain in OA include subchondral microfractures, bone stretching with elevation of the periosteum due to osteophyte growth, bone remodeling and repair, bone marrow lesions, and bone angina caused by decreased blood flow and increased intra-osseous pressure. Central factors alter pain processing by setting the gain in such a way that, when a peripheral input is present, it is processed against a background of central factors that can enhance or diminish the experience of pain. As a complex phenomenon with a strong subjective component, pain can also be influenced by the nature of the underlying disease, personal predisposition (biological and psychological, and environmental and psychosocial factors. This review examines the current literature regarding the sources and mechanisms of pain in OA.

DNA Methylation Modulates Nociceptive Sensitization after Incision.

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Yuan Sun

Full Text Available DNA methylation is a key epigenetic mechanism controlling DNA accessibility and gene expression. Blockade of DNA methylation can significantly affect pain behaviors implicated in neuropathic and inflammatory pain. However, the role of DNA methylation with regard to postoperative pain has not yet been explored. In this study we sought to investigate the role of DNA methylation in modulating incisional pain and identify possible targets under DNA methylation and contributing to incisional pain. DNA methyltranferase (DNMT inhibitor 5-Aza-2'-deoxycytidine significantly reduced incision-induced mechanical allodynia and thermal sensitivity. Aza-2'-deoxycytidine also reduced hindpaw swelling after incision, suggesting an anti-inflammatory effect. Global DNA methylation and DNMT3b expression were increased in skin after incision, but none of DNMT1, DNMT3a or DNMT3b was altered in spinal cord or DRG. The expression of proopiomelanocortin Pomc encoding β-endorphin and Oprm1 encoding the mu-opioid receptor were upregulated peripherally after incision; moreover, Oprm1 expression was further increased under DNMT inhibitor treatment. Finally, local peripheral injection of the opioid receptor antagonist naloxone significantly exacerbated incision-induced mechanical hypersensitivity. These results suggest that DNA methylation is functionally relevant to incisional nociceptive sensitization, and that mu-opioid receptor signaling might be one methylation regulated pathway controlling sensitization after incision.

Metformin increases pressure pain threshold in lean women with polycystic ovary syndrome

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Kiałka M

2016-08-01

Full Text Available Marta Kiałka,1 Tomasz Milewicz,1 Krystyna Sztefko,2 Iwona Rogatko,2 Renata Majewska3 1Department of Gynecological Endocrinology, Jagiellonian University, Medical College, Kraków, Poland; 2Department of Clinical Biochemistry, Jagiellonian University, Medical College, Kraków, Poland; 3Department of Epidemiology, Chair of Epidemiology and Preventive Medicine, Jagiellonian University Medical College, Kraków, Poland Background: Despite the strong preclinical rationale, there are only very few data considering the utility of metformin as a potential pain therapeutic in humans. The aim of this study was to determine the association between metformin therapy and pressure pain threshold (PPT in lean women with polycystic ovary syndrome (PCOS. We hypothesized that metformin therapy in lean PCOS women increases PPT. Materials and methods: Twenty-seven lean PCOS women with free androgen index phenotype >5 and 18 lean healthy controls were enrolled in the study. Fifteen of the PCOS women were randomly assigned to be treated with metformin 1,500 mg daily for 6 months. PPT and plasma β-endorphin levels were measured in all women at the beginning of the study and after 6 months of observation. Results: We observed an increase in PPT values measured on deltoid and trapezius muscle in the PCOS with metformin group after 6 months of metformin administration (4.81±0.88 kg/cm², P<0.001 on deltoid muscle, and 5.71±1.16 kg/cm² on trapezius muscle. We did not observe any significant changes in PPT values in the PCOS without treatment group and in controls. We did not observe any significant changes in serum β-endorphin levels in any studied groups during the 6-month observation. Conclusion: We conclude that metformin therapy increases PPT in lean PCOS women, without affecting plasma β-endorphin concentration. Our results may suggest the potential role of metformin in pain therapy. We propose that larger, randomized studies on metformin impact on pain

Multiple Nonspecific Sites of Joint Pain Outside the Knees Develop in Persons With Knee Pain.

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Felson, David T; Niu, Jingbo; Quinn, Emily K; Neogi, Tuhina; Lewis, Cara L; Lewis, Cora E; Frey Law, Laura; McCulloch, Chuck; Nevitt, Michael; LaValley, Michael

2017-02-01

Many persons with knee pain have joint pain outside the knee, but despite the impact and high frequency of this pain, its distribution and causes have not been studied. We undertook this study to test the hypothesis of those studying gait abnormalities who have suggested that knee pain causes pain in adjacent joints but that pain adaptation strategies are highly individualized. We studied persons ages 50-79 years with or at high risk of knee osteoarthritis who were recruited from 2 community-based cohorts, the Multicenter Osteoarthritis Study and the Osteoarthritis Initiative, and we followed them up for 5-7 years. We excluded those with knee pain at baseline and compared those who had developed knee pain at the first follow-up examination (the index visit) with those who had not. We examined pain on most days at joint regions outside the knee in examinations after the index visit. Logistic regression analyses examined the risk of joint-specific pain adjusted for age, sex, body mass index, and symptoms of depression, and we performed sensitivity analyses excluding those with widespread pain. In the combined cohorts, 693 persons had knee pain at the index visit and 2,793 did not. A total of 79.6% of those with bilateral knee pain and 63.8% of those with unilateral knee pain had pain during follow-up in a joint region outside the knee, compared with 49.9% of those without knee pain. There was an increased risk of pain at most extremity joint sites, without a predilection for specific sites. Results were unchanged when those with widespread pain were excluded. Persons with chronic knee pain are at increased risk of pain in multiple joints in no specific pattern. © 2016, American College of Rheumatology.

Patients With Knee Osteoarthritis Who Score Highly on the PainDETECT Questionnaire Present With Multimodality Hyperalgesia, Increased Pain, and Impaired Physical Function.

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Moss, Penny; Benson, Heather A E; Will, Rob; Wright, Anthony

2018-01-01

PainDETECT is a self-report questionnaire that can be used to identify features of neuropathic pain. A proportion of patients with knee osteoarthritis (OA) score highly on the PainDETECT questionnaire. This study aimed to determine whether those with a higher "positive neuropathic" score on the PainDETECT questionnaire also had greater pain, hypersensitivity, and reduced function compared with individuals with knee OA with lower PainDETECT scores. In total, 130 participants with knee OA completed the PainDETECT, Western Ontario and McMaster Universities Arthritis Index (WOMAC), and Pain Quality Assessment Scale questionnaires. Quantitative sensory testing was carried out at 3 sites (both knees and elbow) using standard methods. Cold and heat pain thresholds were tested using a Peltier thermode and pressure pain thresholds using a digital algometer. Physical function was assessed using 3 timed locomotor function tests. In total, 22.3% of participants scored in the "positive neuropathic" category with a further 35.4% in the unclear category. Participants in the "positive neuropathic" category reported higher levels of pain and more impaired function based on the WOMAC questionnaire (Ppain thresholds at the OA knee. They were also slower to complete 2 of the locomotion tasks. This study identified a specific subgroup of people with knee OA who exhibited PainDETECT scores in the "positive neuropathic" category. These individuals experienced increased levels of pain, widespread, multimodality hyperalgesia, and greater functional impairment than the remaining cohort. Identification of OA patients with this pain phenotype may permit more targeted and effective pain management.

Differentiation of pain ratings in combat-related posttraumatic stress disorder.

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Kraus, Anja; Geuze, Elbert; Schmahl, Christian; Greffrath, Wolfgang; Treede, Rolf-Detlef; Bohus, Martin; Vermetten, Eric

2009-06-01

Although posttraumatic stress disorder (PTSD) is associated with chronic pain, preliminary evidence suggests reduced experimental pain sensitivity in this disorder. The questions addressed in the present study were whether pain perception would also be reduced in PTSD patients who are not suffering from chronic pain symptoms, and whether a reduction in pain sensitivity would also be present in combat veterans who did not develop PTSD. For this, we determined thermal detection and pain thresholds in 10 male combat-related PTSD patients, 10 combat control subjects (no PTSD) and 10 healthy controls without combat experience. All subjects were pain free. First, we measured thermal sensory thresholds with ramped heat and cold stimuli using the method of limits. Ramped thermal sensory stimulation revealed no deficits for the detection of (non-noxious) f2.1thermal stimuli between groups. In contrast, heat and cold pain thresholds in both combat groups (PTSD and combat controls) were significantly increased compared to healthy controls. However, these stimuli could not distinguish between the two groups due to ceiling effects. When using longer-lasting heat stimulation at different temperatures (30s duration; method of fixed stimuli), we found significantly lower frequency of pain reports in PTSD patients compared with both combat and healthy controls, as well as significantly lower pain ratings. Our results suggest an association of PTSD with reduced pain sensitivity, which could be related to PTSD-related (neuro-)psychological alterations or to a pre-existing risk factor for the disorder.

Feeling the pain of others is associated with self-other confusion and prior pain experience.

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Derbyshire, Stuart W G; Osborn, Jody; Brown, Steven

2013-01-01

Some chronic pain patients and healthy individuals experience pain when observing injury or others in pain. To further understand shared pain, we investigated perspective taking, bodily ownership and tooth pain sensitivity. First, participants who reported shared pain (responders) and those who did not (non-responders) viewed an avatar on a screen. Intermittently, 0-3 circles appeared. Sometimes the participant's and avatar's perspective were consistent, both directly viewed the same circles, and sometimes inconsistent, both directly viewed different circles. Responders were faster than non-responders to identify the number of circles when adopting a consistent perspective. Second, participants sat with their left hand hidden while viewing a rubber hand. All participants reported an illusory sensation of feeling stroking in the rubber hand and a sense of ownership of the rubber hand during synchronous stroking of the rubber and hidden hand. The responders also reported feeling the stroking and a sense of ownership of the rubber hand during asynchronous stroking. For experiment three, participants with either low, moderate, or high tooth sensitivity observed a series of images depicting someone eating an ice-popsicle. Low sensitivity participants never reported pain. In contrast, moderate and high sensitivity participants reported pain in response to an image depicting someone eating an ice popsicle (4 and 19% of the time, respectively) and depicting someone eating an ice-popsicle and expressing pain (23 and 40%, respectively). In summary, responders have reduced ability to distinguish their own and others' visual perspective and enhanced ability to integrate a foreign arm into their bodily representation. The tendency to share pain is also enhanced when an observed pain is commonly experienced by the observer. Shared pain may therefore involve reactivation of pain memories or pain schema that are readily integrated into a self perspective and bodily representation.

Feeling the pain of others is associated with self-other confusion and prior pain experience

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Stuart W G Derbyshire

2013-08-01

Full Text Available Some chronic pain patients and healthy individuals experience pain when observing injury or others in pain. To further understand shared pain, we investigated perspective taking, bodily ownership and tooth pain sensitivity. First, participants who reported shared pain (responders and those who did not (non-responders viewed an avatar on a screen. Intermittently, 0-3 circles appeared. Sometimes the participant's and avatar's perspective were consistent, both directly viewed the same circles, and sometimes inconsistent, both directly viewed different circles. Responders were faster than non-responders to identify the number of circles when adopting a consistent perspective. Second, participants sat with their left hand hidden while viewing a rubber hand. All participants reported an illusory sensation of feeling stroking in the rubber hand and a sense of ownership of the rubber hand during synchronous stroking of the rubber and hidden hand. The responders also reported feeling the stroking and a sense of ownership of the rubber hand during asynchronous stroking. For experiment three, participants with either low, moderate or high tooth sensitivity observed a series of images depicting someone eating an ice-popsicle. Low sensitivity participants never reported pain. In contrast, moderate and high sensitivity participants reported pain in response to an image depicting someone eating an ice popsicle (4% and 19% of the time, respectively and depicting someone eating an ice-popsicle and expressing pain (23% and 40%, respectively. In summary, responders have reduced ability to distinguish their own and others' visual perspective and enhanced ability to integrate a foreign arm into their bodily representation. The tendency to share pain is also enhanced when an observed pain is commonly experienced by the observer. Shared pain may therefore involve reactivation of pain memories or pain schema that are readily integrated into a self perspective and

Comparative Responsiveness of the PROMIS Pain Interference Short Forms, Brief Pain Inventory, PEG, and SF-36 Bodily Pain Subscale.

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Kean, Jacob; Monahan, Patrick O; Kroenke, Kurt; Wu, Jingwei; Yu, Zhangsheng; Stump, Tim E; Krebs, Erin E

2016-04-01

To compare the sensitivity to change and the responsiveness to intervention of the PROMIS Pain Interference short forms, Brief Pain Inventory (BPI), 3-item PEG scale, and SF-36 Bodily Pain subscale in a sample of patients with persistent musculoskeletal pain of moderate severity. Standardized response means, standardized effect sizes, and receiver operating curve analyses were used to assess change between baseline and 3-month assessments in 250 participants who participated in a randomized clinical effectiveness trial of collaborative telecare management for moderate to severe and persistent musculoskeletal pain. The BPI, PEG, and SF-36 Bodily Pain measures were more sensitive to patient-reported global change than the PROMIS Pain Interference short forms, especially for the clinically improved group, for which the change detected by the PROMIS short forms was not statistically significant. The BPI was more responsive to the clinical intervention than the SF-36 Bodily Pain and PROMIS Pain Interference measures. Post hoc analyses exploring these findings did not suggest that differences in content or rating scale structure (number of response options or anchoring language) adequately explained the observed differences in the detection of change. In this clinical trial, the BPI and PEG measures were better able to detect change than the SF-36 Bodily Pain and PROMIS Pain Interference measures.

Assessment of pressure-pain thresholds and central sensitization of pain in lateral epicondylalgia

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Jespersen, Anders; Amris, Kirstine; Graven-Nielsen, Thomas

2013-01-01

pressure stimulation at intensity relative to the individual pain threshold, the pain intensity was continuously recorded using an electronic visual analogue scale (VAS), and from this the degree of temporal summation was estimated. For LE, a Doppler ultrasound examination of the elbow was made to identify...

Adverse social experiences in adolescent rats result in enduring effects on social competence, pain sensitivity and endocannabinoid signaling

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Peggy Schneider

2016-10-01

Full Text Available Social affiliation is essential for many species and gains significant importance during adolescence. Disturbances in social affiliation, in particular social rejection experiences during adolescence, affect an individual’s well-being and are involved in the emergence of psychiatric disorders. The underlying mechanisms are still unknown, partly because of a lack of valid animal models. By using a novel animal model for social peer-rejection, which compromises adolescent rats in their ability to appropriately engage in playful activities, here we report on persistent impairments in social behavior and dysregulations in the endocannabinoid system. From postnatal day (pd 21 to pd 50 adolescent female Wistar rats were either reared with same-strain partners (control or within a group of Fischer 344 rats (inadequate social rearing, ISR, previously shown to serve as inadequate play partners for the Wistar strain. Adult ISR animals showed pronounced deficits in social interaction, social memory, processing of socially transmitted information, and decreased pain sensitivity. Molecular analysis revealed increased CB1 receptor protein levels and CP55,940 stimulated 35SGTPγS binding activity specifically in the amygdala and thalamus in previously peer-rejected rats. Along with these changes, increased levels of the endocannabinoid anandamide and a corresponding decrease of its degrading enzyme fatty acid amide hydrolase were seen in the amygdala. Our data indicate lasting consequences in social behavior and pain sensitivity following peer-rejection in adolescent female rats. These behavioral impairments are accompanied by persistent alterations in CB1 receptor signaling. Finally, we provide a novel translational approach to characterize neurobiological processes underlying social peer-rejection in adolescence.

Pain and the ethics of pain management.

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Edwards, R B

1984-01-01

In this article I clarify the concepts of 'pain', 'suffering', 'pains of body', 'pains of soul'. I explore the relevance of an ethic to the clinical setting which gives patients a strong prima facie right to freedom from unnecessary and unwanted pain and which places upon medical professionals two concomitant moral obligations to patients. First, there is the duty not to inflict pain and suffering beyond what is necessary for effective diagnosis, treatment and research. Next, there is the duty to do all that can be done to relieve all the pain and suffering which can be alleviated. I develop in some detail that individuality of pain sensitivity must be taken into account in fulfilling these obligations. I explore the issue of the relevance of informed consent and the right to refuse treatment to the matter of pain relief. And I raise the question of what conditions, if any, should override the right to refuse treatment where pain relief is of paramount concern.

Effects of music engagement on responses to painful stimulation.

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Bradshaw, David H; Chapman, C Richard; Jacobson, Robert C; Donaldson, Gary W

2012-06-01

We propose a theoretical framework for the behavioral modulation of pain based on constructivism, positing that task engagement, such as listening for errors in a musical passage, can establish a construction of reality that effectively replaces pain as a competing construction. Graded engagement produces graded reductions in pain as indicated by reduced psychophysiological arousal and subjective pain report. Fifty-three healthy volunteers having normal hearing participated in 4 music listening conditions consisting of passive listening (no task) or performing an error detection task varying in signal complexity and task difficulty. During all conditions, participants received normally painful fingertip shocks varying in intensity while stimulus-evoked potentials (SEP), pupil dilation responses (PDR), and retrospective pain reports were obtained. SEP and PDR increased with increasing stimulus intensity. Task performance decreased with increasing task difficulty. Mixed model analyses, adjusted for habituation/sensitization and repeated measures within person, revealed significant quadratic trends for SEP and pain report (Pchangemusic listening task. Engaging activities may prevent pain by creating competing constructions of reality that draw on the same processing resources as pain. Better understanding of these processes will advance the development of more effective pain modulation through improved manipulation of engagement strategies.

The most physically active Danish adolescents are at increased risk for developing spinal pain

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Aartun, Ellen; Boyle, Eleanor; Hartvigsen, Jan

2016-01-01

BACKGROUND: The overall aim of this study was to determine to what extent objectively measured physical activity in a school-based sample aged 11-13 years predicted incident cases of spinal pain (neck pain, mid back pain or low back pain) over the following 2 years. METHODS: Data were collected...... was defined as a report of pain in at least one spinal area at follow-up. Physical activity was measured objectively using the Actigraph GT3X Triaxial Activity Monitor for 1 week. RESULTS: Objectively measured sedentary activity, moderate-to-vigorous physical activity and vigorous physical activity were...... generally not predictive of the 2-year incidence of spinal pain. However, 10% of participants with the highest proportion of the day spent in vigorous physical activity were at increased risk of reporting spinal pain at follow-up with a relative risk (RR) of 1.44 (95% CI 1.09 to 1.91). For the overall...

Association between increase in vertical ground reaction force loading rate and pain level in women with patellofemoral pain after a patellofemoral joint loading protocol.

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Briani, Ronaldo Valdir; Pazzinatto, Marcella Ferraz; Waiteman, Marina Cabral; de Oliveira Silva, Danilo; de Azevedo, Fábio Mícolis

2018-04-11

The etiology of patellofemoral pain (PFP) is thought to be the result of increased patellofemoral joint (PFJ) load and aberrant lower extremity mechanics, including altered vertical ground reaction forces (VGRF). However, few studies have investigated the association between an increase in pain and VGRF loading rates in the context of PFP. Thus, this study aimed to investigate the immediate effects of PFJ loading on pain and VGRF loading rate, and to see if there is a link between modification of both pain and VGRF loading rate during stair negotiation. Thirty-four women with PFP underwent VGRF analysis during stair negotiation under two conditions: with (condition 2) and without (condition 1) being previously submitted to a PFJ loading protocol in order to or not to exacerbate their knee pain, respectively. The VGRF loading rates were significantly higher in condition 2 (Mean ± standard deviation (SD)=4.0±0.6N/s) compared to condition 1 (Mean±SD=3.6±0.5N/s) during stair ascent and during stair descent (Mean±SD: condition 1=6.3±1.1N/s; condition 2=7.0±1.4N/s). In addition, VGRF loading rates were higher during stair descent compared to stair ascent in both conditions. There were significant correlations between the increase in pain and VGRF loading rate during both tasks. There seemed to be an important relation between the increase in pain and VGRF loading rates in women with PFP. Based on these findings, interventions aimed at reducing VGRF loading rates are important in the context of PFP. Copyright © 2018 Elsevier B.V. All rights reserved.

Fear of movement, passive coping, manual handling, and severe or radiating pain increase the likelihood of sick leave due to low back pain.

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Dawson, Anna P; Schluter, Philip J; Hodges, Paul W; Stewart, Simon; Turner, Catherine

2011-07-01

Sick leave due to low back pain (LBP-SL) is costly and compromises workforce productivity. The fear-avoidance model asserts that maladaptive pain-related cognitions lead to avoidance and disuse, which can perpetuate ongoing pain. Staying home from work is an avoidant behavior, and hence pain-related psychological features may help explain LBP-SL. We examined the relative contribution of pain catastrophizing, fear of movement, and pain coping (active and passive) in LBP-SL in addition to pain characteristics and other psychosocial, occupational, general health, and demographic factors. Two-way interactions between age and gender and candidate exposures were also considered. Our sample comprised 2164 working nurses and midwives with low back pain in the preceding year. Binary logistic regression was performed on cross-sectional data by manual backward stepwise elimination of nonsignificant terms to generate a parsimonious multivariable model. From an extensive array of exposures assessed, fear of movement (women, odds ratio [OR]=1.05, 95% confidence interval [CI] 1.02-1.08; men, OR=1.17, 95% CI 1.05-1.29), passive coping (OR=1.07, 95% CI 1.04-1.11), pain severity (OR=1.61, 95% CI 1.50-1.72), pain radiation (women, OR=1.45, 95% CI 1.10-1.92; men, OR=4.13, 95% CI 2.15-7.95), and manual handling frequency (OR=1.03, 95% CI 1.01-1.05) increased the likelihood of LBP-SL in the preceding 12 months. Administrators and managers were less likely to report LBP-SL (OR=0.44, 95% CI 0.27-0.71), and age had a protective effect in individuals in a married or de facto relationship (OR=0.97, 95% CI 0.95-0.98). In summary, fear of movement, passive coping, frequent manual handling, and severe or radiating pain increase the likelihood of LBP-SL. Gender-specific responses to pain radiation and fear of movement are evident. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

Deep pain sensitivity is correlated with oral-health-related quality of life but not with prosthetic factors in complete denture wearers

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Yuri Martins COSTA

2015-12-01

Full Text Available ABSTRACT Low pressure Pain Threshold (PPT is considered a risk factor for Temporomandibular Disorders (TMD and is influenced by psychological variables. Objectives To correlate deep pain sensitivity of masticatory muscles with prosthetic factors and Oral-Health-Related Quality of Life (OHRQoL in completely edentulous subjects. Material and Methods A total of 29 complete denture wearers were recruited. The variables were: a Pressure Pain Threshold (PPT of the masseter and temporalis; b retention, stability, and tooth wear of dentures; c Vertical Dimension of Occlusion (VDO; d Oral Health Impact Profile (OHIP adapted to orofacial pain. The Kolmogorov-Smirnov test, the Pearson Product-Moment correlation coefficient, the Spearman Rank correlation coefficient, the Point-Biserial correlation coefficient, and the Bonferroni correction (α=1% were applied to the data. Results The mean age (standard deviation of the participants was of 70.1 years (9.5 and 82% of them were females. There were no significant correlations with prosthetic factors, but significant negative correlations were found between the OHIP and the PPT of the anterior temporalis (r=-0.50, 95% CI-0.73 to 0.17, p=0.005. Discussion The deep pain sensitivity of masticatory muscles in complete dentures wearers is associated with OHRQoL, but not with prosthetic factors.

Deep pain sensitivity is correlated with oral-health-related quality of life but not with prosthetic factors in complete denture wearers

Science.gov (United States)

COSTA, Yuri Martins; PORPORATTI, André Luís; HILGENBERG-SYDNEY, Priscila Brenner; BONJARDIM, Leonardo Rigoldi; CONTI, Paulo César Rodrigues

2015-01-01

ABSTRACT Low pressure Pain Threshold (PPT) is considered a risk factor for Temporomandibular Disorders (TMD) and is influenced by psychological variables. Objectives To correlate deep pain sensitivity of masticatory muscles with prosthetic factors and Oral-Health-Related Quality of Life (OHRQoL) in completely edentulous subjects. Material and Methods A total of 29 complete denture wearers were recruited. The variables were: a) Pressure Pain Threshold (PPT) of the masseter and temporalis; b) retention, stability, and tooth wear of dentures; c) Vertical Dimension of Occlusion (VDO); d) Oral Health Impact Profile (OHIP) adapted to orofacial pain. The Kolmogorov-Smirnov test, the Pearson Product-Moment correlation coefficient, the Spearman Rank correlation coefficient, the Point-Biserial correlation coefficient, and the Bonferroni correction (α=1%) were applied to the data. Results The mean age (standard deviation) of the participants was of 70.1 years (9.5) and 82% of them were females. There were no significant correlations with prosthetic factors, but significant negative correlations were found between the OHIP and the PPT of the anterior temporalis (r=-0.50, 95% CI-0.73 to 0.17, p=0.005). Discussion The deep pain sensitivity of masticatory muscles in complete dentures wearers is associated with OHRQoL, but not with prosthetic factors. PMID:26814457

Effects of vicarious pain on self-pain perception: investigating the role of awareness

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Terrighena EL

2017-07-01

Full Text Available Esslin L Terrighena,1,2 Ge Lu,1 Wai Ping Yuen,1 Tatia M C Lee,1–4 Kati Keuper1,2,5 1Department of Psychology, Laboratory of Neuropsychology, The University of Hong Kong, Hong Kong; 2Laboratory of Social Cognitive Affective Neuroscience, The University of Hong Kong, Hong Kong; 3The State Key Laboratory of Brain and Cognitive Sciences, Hong Kong; 4Institute of Clinical Neuropsychology, The University of Hong Kong, Hong Kong; 5Institute for Biomagnetism and Biosignalanalysis, University of Münster, Münster, Germany Abstract: The observation of pain in others may enhance or reduce self-pain, yet the boundary conditions and factors that determine the direction of such effects are poorly understood. The current study set out to show that visual stimulus awareness plays a crucial role in ­determining whether vicarious pain primarily activates behavioral defense systems that enhance pain sensitivity and stimulate withdrawal or appetitive systems that attenuate pain sensitivity and stimulate approach. We employed a mixed factorial design with the between-subject factors exposure time (subliminal vs optimal and vicarious pain (pain vs no pain images, and the within-subject factor session (baseline vs trial to investigate how visual awareness of vicarious pain images affects subsequent self-pain in the cold-pressor test. Self-pain tolerance, intensity and unpleasantness were evaluated in a sample of 77 healthy participants. Results revealed ­significant interactions of exposure time and vicarious pain in all three dependent measures. In the presence of visual awareness (optimal condition, vicarious pain compared to no-pain elicited overall enhanced self-pain sensitivity, indexed by reduced pain tolerance and enhanced ratings of pain intensity and unpleasantness. Conversely, in the absence of visual awareness (subliminal condition, vicarious pain evoked decreased self-pain intensity and unpleasantness while pain tolerance remained unaffected. These

[Role of the Periaqueductal Gray Matter of the Midbrain in Regulation of Somatic Pain Sensitivity During Stress: Participation of Corticotropin-Releasing Factor and Glucocorticoid Hormones].

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Yarushkina, N I; Filaretova, L P

2015-01-01

Periaqueductal gray matter of the midbrain (PAGM) plays a crucial role in the regulation of pain sensitivity under stress, involving in the stress-induced analgesia. A key hormonal system of adaptation under stress is the hypothalamic-pituitary-adrenocortical (HPA) axis. HPA axis's hormones, corticotropin-releasing factor (CRF) and glucocorticoids, are involved in stress-induced analgesia. Exogenous hormones of the HPA axis, similarly to the hormones produced under stress, may cause an analgesic effect. CRF-induced analgesia may be provided by glucocorticoid hormones. CRF and glucocorticoids-induced effects on somatic pain sensitivity may be mediated by PAGM. The aim of the review was to analyze the data of literature on the role of PAGM in the regulation of somatic pain sensitivity under stress and in providing of CRF and glucocorticoid-induced analgesia.

Relationship between mechanical sensitivity and postamputation pain: A prospective study

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Nikolajsen, Lone; IlKjær, Susanne; Jensen, Troels Staehelin

2000-01-01

of the limb and early (after 1 week) and late (after 6 months) phantom pain. Thirty-five patients scheduled for amputation of the lower limb were examined before, 1 week and 6 months after amputation. On all three examination days pressure-pain thresholds were measured and compared with the simultaneous...... recording of ongoing pain intensity assessed on a visual analogue scale (VAS). There was a weak but significant inverse relationship between preamputation thresholds and early stump and phantom pain. There was no relationship between preamputation thresholds and late stump and phantom pain. One week after...... amputation there was a significant and inverse relationship between mechanical thresholds and phantom pain but no relationship was found after 6 months. The findings suggest that although tenderness of the limb before and after amputation is related to early stump and phantom pain, the relationship is weak...

Language and the pain experience.

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Wilson, Dianne; Williams, Marie; Butler, David

2009-03-01

descriptors highlighted discrepancies between the studies. As well as the diversity of pain descriptors used in studies, they were inconsistently categorized into domains of pain. A lack of consistent bias towards certain pain descriptors was observed, and may be explained simply by the fact that the words provided are not those which subjects themselves would use. These findings suggest that the multidimensional and individual nature of the persistent pain experience may not be adequately explained by pain questionnaires such as the MPQ. Personalized pain descriptors may communicate the pain experience more appropriately, but may also contribute to an increased sensitivity of cortical pain processing areas by capturing increased attention for that individual. The language used as part of communication between therapists and people with persistent pain may provide an, as yet, unexplored adjunct strategy in management. Copyright (c) 2008 John Wiley & Sons, Ltd.

Chronic Widespread Back Pain is Distinct From Chronic Local Back Pain: Evidence From Quantitative Sensory Testing, Pain Drawings, and Psychometrics.

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Gerhardt, Andreas; Eich, Wolfgang; Janke, Susanne; Leisner, Sabine; Treede, Rolf-Detlef; Tesarz, Jonas

2016-07-01

Whether chronic localized pain (CLP) and chronic widespread pain (CWP) have different mechanisms or to what extent they overlap in their pathophysiology is controversial. The study compared quantitative sensory testing profiles of nonspecific chronic back pain patients with CLP (n=48) and CWP (n=29) with and fibromyalgia syndrome (FMS) patients (n=90) and pain-free controls (n = 40). The quantitative sensory testing protocol of the "German-Research-Network-on-Neuropathic-Pain" was used to measure evoked pain on the painful area in the lower back and the pain-free hand (thermal and mechanical detection and pain thresholds, vibration threshold, pain sensitivity to sharp and blunt mechanical stimuli). Ongoing pain and psychometrics were captured with pain drawings and questionnaires. CLP patients did not differ from pain-free controls, except for lower pressure pain threshold (PPT) on the back. CWP and FMS patients showed lower heat pain threshold and higher wind-up ratio on the back and lower heat pain threshold and cold pain threshold on the hand. FMS showed lower PPT on back and hand, and higher comorbidity of anxiety and depression and more functional impairment than all other groups. Even after long duration CLP presents with a local hypersensitivity for PPT, suggesting a somatotopically specific sensitization of nociceptive processing. However, CWP patients show widespread ongoing pain and hyperalgesia for different stimuli that is generalized in space, suggesting the involvement of descending control systems, as also suggested for FMS patients. Because mechanisms in nonspecific chronic back pain with CLP and CWP differ, these patients should be distinguished in future research and allocated to different treatments.

Increased multiple sclerosis relapses related to lower prevalence of pain

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José Vinícius Martins da Silva

2015-07-01

Full Text Available Objective The study aims to investigate the presence of pain amongst multiple sclerosis (MS patients. Method One hundred MS patients responded to questionnaires evaluating neuropathic and nociceptive pain, depression and anxiety. Statistical analysis was performed using the Mann–Whitney U, Chi-Square and two-tailed Fisher’s exact tests and multivariate logistic regression. Results Women had a statistically higher prevalence of pain (p = 0.037, and chances of having pain after the age of 50 reduced. Women with pain had a statistically significant lower number of relapses (p = 0.003, restricting analysis to those patients with more than one relapse. After the second relapse, each relapse reduced the chance of having pain by 46%. Presence of pain was independent of Expanded Disability Status Scale (EDSS anxiety, and depression. Conclusion Our findings suggest a strong inverse association between relapses and pain indicating a possible protective role of focal inflammation in the control of pain.

Local and Systemic Changes in Pain Sensitivity After 4 Weeks of Calf Muscle Stretching in a Nonpainful Population

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Bartholdy, Cecilie; Zangger, Graziella; Hansen, Lisbeth

2016-01-01

BACKGROUND: Stretching is often used in clinical practice for a variety of purposes, including pain therapy. The possible mechanism behind the effect of stretching remains to be clarified. AIM: To investigate whether 4 weeks of unilateral stretching of the calf muscles would affect local...... and central pain sensitivity. METHOD: This study was a randomized assessor-blinded clinical study. Healthy participants (age 18 to 40) were included and randomized. Participants in the intervention group were instructed to perform 2 stretching exercises targeting the calf muscles; 3 times 30 seconds, 7 days...... a week for 4 weeks on the dominant leg. Participants in the control group were instructed not to do any stretching for 4 weeks. Pressure pain threshold (PPT) and temporal summation (TS) of pressure pain were measured on the stretched calf, the contra-lateral calf, and contra-lateral lower arm using...

Diagnostic value of exercise-induced changes in circulating high sensitive troponin T in stable chest pain patients

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Mouridsen, Mette Rauhe; Nielsen, Olav Wendelboe; Pedersen, Ole Dyg

2013-01-01

We investigated the diagnostic value of exercise-induced increase in cardiac Troponin T (cTnT) in stable chest pain subjects.......We investigated the diagnostic value of exercise-induced increase in cardiac Troponin T (cTnT) in stable chest pain subjects....

Neuropathic pain and cytokines: current perspectives

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Clark AK

2013-11-01

Full Text Available Anna K Clark, Elizabeth A Old, Marzia Malcangio Wolfson Centre for Age Related Diseases, King's College London, London, UK Abstract: Neuropathic pain represents a major problem in clinical medicine because it causes debilitating suffering and is largely resistant to currently available analgesics. A characteristic of neuropathic pain is abnormal response to somatic sensory stimulation. Thus, patients suffering peripheral neuropathies may experience pain caused by stimuli which are normally nonpainful, such as simple touching of the skin or by changes in temperature, as well as exaggerated responses to noxious stimuli. Convincing evidence suggests that this hypersensitivity is the result of pain remaining centralized. In particular, at the first pain synapse in the dorsal horn of the spinal cord, the gain of neurons is increased and neurons begin to be activated by innocuous inputs. In recent years, it has become appreciated that a remote damage in the peripheral nervous system results in neuronal plasticity and changes in microglial and astrocyte activity, as well as infiltration of macrophages and T cells, which all contribute to central sensitization. Specifically, the release of pronociceptive factors such as cytokines and chemokines from neurons and non-neuronal cells can sensitize neurons of the first pain synapse. In this article we review the current evidence for the role of cytokines in mediating spinal neuron–non-neuronal cell communication in neuropathic pain mechanisms following peripheral nerve injury. Specific and selective control of cytokine-mediated neuronal–glia interactions results in attenuation of the hypersensitivity to both noxious and innocuous stimuli observed in neuropathic pain models, and may represent an avenue for future therapeutic intervention. Keywords: anti-inflammatory cytokines, proinflammatory cytokines, microglia, astrocytes, first pain synapse

Electrodermal responses to words in chronic low back pain patients: a comparison between pain descriptors, other emotional words, and neutral words.

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Bonnet, Adeline; Naveteur, Janick

2006-10-01

This study examines the electrodermal reactivity of chronic sufferers to emotional words. The hypothesis that patients are over-sensitive to pain descriptors is tested. Electrodermal activity was recorded in 12 chronic low back pain patients and 12 healthy controls during passive viewing of words on a video monitor. These words were pain descriptors, other emotional words, and neutral words, in a pseudo-randomized order. A jingle was associated with the word occurrence. In chronic low back pain patients, skin conductance responses (SCRs) induced by pain descriptors or other emotional words were larger than SCRs induced by neutral words but they did not differ from each other. Patients presented SCRs, which were both larger and faster than those of controls, including following neutral words. There was no significant effect of word type in controls. Skin conductance level and the number of nonspecific fluctuations were larger in patients as compared with controls. The present electrodermal study suggests that chronic pain is linked to an increased reactivity to a wide range of stimuli. Emotional load amplifies the effect. This leads to recommend broad therapeutic management in chronic sufferers. Contrary to expectation derived from classical conditioning, patients did not prove over-sensitive to pain descriptors. This negative finding is discussed at methodologic, physiologic, and psychologic levels.

Sex differences in pain: a brief review of clinical and experimental findings.

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Bartley, E J; Fillingim, R B

2013-07-01

Recent years have witnessed substantially increased research regarding sex differences in pain. The expansive body of literature in this area clearly suggests that men and women differ in their responses to pain, with increased pain sensitivity and risk for clinical pain commonly being observed among women. Also, differences in responsivity to pharmacological and non-pharmacological pain interventions have been observed; however, these effects are not always consistent and appear dependent on treatment type and characteristics of both the pain and the provider. Although the specific aetiological basis underlying these sex differences is unknown, it seems inevitable that multiple biological and psychosocial processes are contributing factors. For instance, emerging evidence suggests that genotype and endogenous opioid functioning play a causal role in these disparities, and considerable literature implicates sex hormones as factors influencing pain sensitivity. However, the specific modulatory effect of sex hormones on pain among men and women requires further exploration. Psychosocial processes such as pain coping and early-life exposure to stress may also explain sex differences in pain, in addition to stereotypical gender roles that may contribute to differences in pain expression. Therefore, this review will provide a brief overview of the extant literature examining sex-related differences in clinical and experimental pain, and highlights several biopsychosocial mechanisms implicated in these male-female differences. The future directions of this field of research are discussed with an emphasis aimed towards further elucidation of mechanisms which may inform future efforts to develop sex-specific treatments.

Children's selective attention to pain and avoidance behaviour: the role of child and parental catastrophizing about pain.

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Vervoort, Tine; Trost, Zina; Van Ryckeghem, Dimitri M L

2013-10-01

The present study investigated selective attention to pain in children, its implications for child avoidance behaviour, and the moderating role of dimensions comprising child and parental catastrophizing about pain (ie, rumination, magnification, and helplessness). Participants were 59 children (31 boys) aged 10-16 years and one of their parents (41 mothers). Children performed a dot-probe task in which child facial pain displays of varying pain expressiveness were presented. Child avoidance behaviour was indexed by child pain tolerance during a cold-pressor task. Children and parents completed measures of child and parent pain catastrophizing, respectively. Findings indicated that both the nature of child selective attention to pain and the impact of selective attention upon child avoidance behaviour were differentially sensitive to specific dimensions of child and parental catastrophizing. Specifically, findings showed greater tendency to shift attention away from pain faces (i.e.,, attentional avoidance) among children reporting greater pain magnification. A similar pattern was observed in terms of parental characteristics, such that children increasingly shifted attention away from pain with increasing levels of parental rumination and helplessness. Furthermore, child attentional avoidance was associated with greater avoidance behaviour (i.e., lower pain tolerance) among children reporting high levels of pain magnification and those whose parents reported greater rumination about pain. The current findings corroborate catastrophizing as a multidimensional construct that may differentially impact outcomes and attest to the importance of assessing both child and parental characteristics in relation to child pain-related attention and avoidance behaviour. Further research directions are discussed. Copyright © 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Steroid injection for shoulder pain causes prolonged increased glucose level in type 1 diabetics

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Povlsen, Bo; Povlsen, Sebastian D

2014-01-01

Shoulder pain is very common in diabetic patients and often treated with steroid injections, with subsequent increases in blood glucose levels or the need for additional insulin being questioned. We report a case of significant and prolonged elevation of blood glucose levels and resultant insulin requirement in a type 1 diabetic man after a single 40 mg injection of triamcinolone for shoulder pain. Within 48 h, the shoulder pain as assessed by a visual analogue scale (0–10) was reduced to zer...

Effects of a Pain Catastrophizing Induction on Sensory Testing in Women with Chronic Low Back Pain: A Pilot Study

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Chloe J. Taub

2017-01-01

Full Text Available Pain catastrophizing, a pattern of negative cognitive-emotional responses to actual or anticipated pain, maintains chronic pain and undermines response to treatments. Currently, precisely how pain catastrophizing influences pain processing is not well understood. In experimental settings, pain catastrophizing has been associated with amplified pain processing. This study sought to clarify pain processing mechanisms via experimental induction of pain catastrophizing. Forty women with chronic low back pain were assigned in blocks to an experimental condition, either a psychologist-led 10-minute pain catastrophizing induction or a control (10-minute rest period. All participants underwent a baseline round of several quantitative sensory testing (QST tasks, followed by the pain catastrophizing induction or the rest period, and then a second round of the same QST tasks. The catastrophizing induction appeared to increase state pain catastrophizing levels. Changes in QST pain were detected for two of the QST tasks administered, weighted pin pain and mechanical allodynia. Although there is a need to replicate our preliminary results with a larger sample, study findings suggest a potential relationship between induced pain catastrophizing and central sensitization of pain. Clarification of the mechanisms through which catastrophizing affects pain modulatory systems may yield useful clinical insights into the treatment of chronic pain.

Effects of a Pain Catastrophizing Induction on Sensory Testing in Women with Chronic Low Back Pain: A Pilot Study.

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Taub, Chloe J; Sturgeon, John A; Johnson, Kevin A; Mackey, Sean C; Darnall, Beth D

2017-01-01

Pain catastrophizing, a pattern of negative cognitive-emotional responses to actual or anticipated pain, maintains chronic pain and undermines response to treatments. Currently, precisely how pain catastrophizing influences pain processing is not well understood. In experimental settings, pain catastrophizing has been associated with amplified pain processing. This study sought to clarify pain processing mechanisms via experimental induction of pain catastrophizing. Forty women with chronic low back pain were assigned in blocks to an experimental condition, either a psychologist-led 10-minute pain catastrophizing induction or a control (10-minute rest period). All participants underwent a baseline round of several quantitative sensory testing (QST) tasks, followed by the pain catastrophizing induction or the rest period, and then a second round of the same QST tasks. The catastrophizing induction appeared to increase state pain catastrophizing levels. Changes in QST pain were detected for two of the QST tasks administered, weighted pin pain and mechanical allodynia. Although there is a need to replicate our preliminary results with a larger sample, study findings suggest a potential relationship between induced pain catastrophizing and central sensitization of pain. Clarification of the mechanisms through which catastrophizing affects pain modulatory systems may yield useful clinical insights into the treatment of chronic pain.

Effects of a Pain Catastrophizing Induction on Sensory Testing in Women with Chronic Low Back Pain: A Pilot Study

Science.gov (United States)

Sturgeon, John A.; Johnson, Kevin A.

2017-01-01

Pain catastrophizing, a pattern of negative cognitive-emotional responses to actual or anticipated pain, maintains chronic pain and undermines response to treatments. Currently, precisely how pain catastrophizing influences pain processing is not well understood. In experimental settings, pain catastrophizing has been associated with amplified pain processing. This study sought to clarify pain processing mechanisms via experimental induction of pain catastrophizing. Forty women with chronic low back pain were assigned in blocks to an experimental condition, either a psychologist-led 10-minute pain catastrophizing induction or a control (10-minute rest period). All participants underwent a baseline round of several quantitative sensory testing (QST) tasks, followed by the pain catastrophizing induction or the rest period, and then a second round of the same QST tasks. The catastrophizing induction appeared to increase state pain catastrophizing levels. Changes in QST pain were detected for two of the QST tasks administered, weighted pin pain and mechanical allodynia. Although there is a need to replicate our preliminary results with a larger sample, study findings suggest a potential relationship between induced pain catastrophizing and central sensitization of pain. Clarification of the mechanisms through which catastrophizing affects pain modulatory systems may yield useful clinical insights into the treatment of chronic pain. PMID:28348505

Physical activity, pain responses to heat stimuli, and conditioned pain modulation in postmenopausal women.

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Adrian, Amanda L; O'Connor, Patrick J; Ward-Ritacco, Christie L; Evans, Ellen M

2015-08-01

Postmenopausal women (PMW) are at high risk for disabling pain and physical inactivity. This study sought to enhance the understanding of relationships between physical activity (PA) and pain among PMW using heat pain sensitivity test and conditioned pain modulation test. We hypothesized that, compared with active women, (i) inactive women would report higher pain intensity and pain unpleasantness ratings; (ii) inactive women in disabling pain would report higher pain intensity and pain unpleasantness at high, but not low, stimulus intensities; and (iii) inactive women would have less modulation. Sixty-eight PMW rated the pain intensity and pain unpleasantness of hot stimuli presented to the thenar eminence of the hand. A subset of 31 women rated the pain intensity of a test stimulus (noxious heat) and a conditioning stimulus (cold water) as part of the conditioned pain modulation task. PA was assessed objectively with accelerometry. Mixed-model analysis of variance (2 × 4 × 2; PA × Temperature × Pain Status) showed that inactive women in disabling pain rated pain unpleasantness higher than active women in disabling pain (F3,192 = 3.526, ∂η = 0.052, P = 0.016). Significantly lower pain unpleasantness ratings were found at the highest stimulus intensity (49°C) only for active women in disabling pain compared with inactive women in disabling pain (t11 = 2.523, P = 0.028). The other hypotheses were not supported. PA is associated with a reduced sensitivity to the unpleasantness of painful high-intensity heat stimuli among women in disabling pain.

Partners' Empathy Increases Pain Ratings: Effects of Perceived Empathy and Attachment Style on Pain Report and Display

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Hurter, Sarah; Paloyelis, Yannis; de C. Williams, Amanda C.; Fotopoulou, Aikaterini

2014-01-01

Pain can be influenced by its social context. We aimed to examine under controlled experimental conditions how empathy from a partner and personal attachment style affect pain report, tolerance, and facial expressions of pain. Fifty-four participants, divided into secure, anxious, and avoidant attachment style groups, underwent a cold pressor task with their partners present. We manipulated how much empathy the participants perceived that their partners had for them. We observed a significant main effect of perceived empathy on pain report, with greater pain reported in the high perceived empathy condition. No such effects were found for pain tolerance or facial display. We also found a significant interaction of empathy with attachment style group, with the avoidant group reporting and displaying less pain than the secure and the anxious groups in the high perceived empathy condition. No such findings were observed in the low empathy condition. These results suggest that empathy from one's partner may influence pain report beyond behavioral reactions. In addition, the amount of pain report and expression that people show in high empathy conditions depends on their attachment style. Perspective Believing that one's partner feels high empathy for one's pain may lead individuals to rate the intensity of pain as higher. Individual differences in attachment style moderate this empathy effect. PMID:24953886

Glia and pain: is chronic pain a gliopathy?

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Ji, Ru-Rong; Berta, Temugin; Nedergaard, Maiken

2013-12-01

Activation of glial cells and neuro-glial interactions are emerging as key mechanisms underlying chronic pain. Accumulating evidence has implicated 3 types of glial cells in the development and maintenance of chronic pain: microglia and astrocytes of the central nervous system (CNS), and satellite glial cells of the dorsal root and trigeminal ganglia. Painful syndromes are associated with different glial activation states: (1) glial reaction (ie, upregulation of glial markers such as IBA1 and glial fibrillary acidic protein (GFAP) and/or morphological changes, including hypertrophy, proliferation, and modifications of glial networks); (2) phosphorylation of mitogen-activated protein kinase signaling pathways; (3) upregulation of adenosine triphosphate and chemokine receptors and hemichannels and downregulation of glutamate transporters; and (4) synthesis and release of glial mediators (eg, cytokines, chemokines, growth factors, and proteases) to the extracellular space. Although widely detected in chronic pain resulting from nerve trauma, inflammation, cancer, and chemotherapy in rodents, and more recently, human immunodeficiency virus-associated neuropathy in human beings, glial reaction (activation state 1) is not thought to mediate pain sensitivity directly. Instead, activation states 2 to 4 have been demonstrated to enhance pain sensitivity via a number of synergistic neuro-glial interactions. Glial mediators have been shown to powerfully modulate excitatory and inhibitory synaptic transmission at presynaptic, postsynaptic, and extrasynaptic sites. Glial activation also occurs in acute pain conditions, and acute opioid treatment activates peripheral glia to mask opioid analgesia. Thus, chronic pain could be a result of "gliopathy," that is, dysregulation of glial functions in the central and peripheral nervous system. In this review, we provide an update on recent advances and discuss remaining questions. Copyright © 2013 International Association for the

Association of Leptin with Body Pain in Women.

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Younger, Jarred; Kapphahn, Kristopher; Brennan, Kathleen; Sullivan, Shannon D; Stefanick, Marcia L

2016-07-01

Leptin, an appetite-regulatory hormone, is also known to act as a proinflammatory adipokine. One of the effects of increased systemic leptin concentrations may be greater sensitivity to pain. We report the results of two studies examining the association between leptin and pain: a small pilot longitudinal study, followed by a large cross-sectional study. In Study 1, three women with physician-diagnosed fibromyalgia provided blood draws daily for 25 consecutive days, as well as daily self-reported musculoskeletal pain. Daily fluctuations in serum leptin were positively associated with pain across all three participants (F (1,63) = 12.8, p BMI) was also included as a predictor of pain. Both leptin and BMI were found to be independently associated with self-reported pain (p = 0.001 and p BMI each being associated with greater pain. Leptin appears to be a predictor of body pain both within- and between-individuals and may be a driver of generalized pain states such as fibromyalgia.

Sensitive Troponin I Assay in Patients with Chest Pain - Association with Significant Coronary Lesions with or Without Renal Failure.

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Soeiro, Alexandre de Matos; Gualandro, Danielle Menosi; Bossa, Aline Siqueira; Zullino, Cindel Nogueira; Biselli, Bruno; Soeiro, Maria Carolina Feres de Almeida; Leal, Tatiana de Carvalho Andreucci Torres; Serrano, Carlos Vicente; Oliveira Junior, Mucio Tavares de

2018-01-01

Despite having higher sensitivity as compared to conventional troponins, sensitive troponins have lower specificity, mainly in patients with renal failure. Study aimed at assessing the sensitive troponin I levels in patients with chest pain, and relating them to the existence of significant coronary lesions. Retrospective, single-center, observational. This study included 991 patients divided into two groups: with (N = 681) and without (N = 310) significant coronary lesion. For posterior analysis, the patients were divided into two other groups: with (N = 184) and without (N = 807) chronic renal failure. The commercial ADVIA Centaur® TnI-Ultra assay (Siemens Healthcare Diagnostics) was used. The ROC curve analysis was performed to identify the sensitivity and specificity of the best cutoff point of troponin as a discriminator of the probability of significant coronary lesion. The associations were considered significant when p renal failure, the areas under the ROC curve were 0.703 (95% CI: 0.66 - 0.74) and 0.608 (95% CI: 0.52 - 0.70), respectively. The best cutoff points to discriminate the presence of significant coronary lesion were: in the general population, 0.605 ng/dL (sensitivity, 63.4%; specificity, 67%); in patients without renal failure, 0.605 ng/dL (sensitivity, 62.7%; specificity, 71%); and in patients with chronic renal failure, 0.515 ng/dL (sensitivity, 80.6%; specificity, 42%). In patients with chest pain, sensitive troponin I showed a good correlation with significant coronary lesions when its level was greater than 0.605 ng/dL. In patients with chronic renal failure, a significant decrease in specificity was observed in the correlation of troponin levels and severe coronary lesions.

Laterality of pain: modulation by placebo and participants' paranormal belief.

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Klemenz, Caroline; Regard, Marianne; Brugger, Peter; Emch, Oliver

2009-09-01

To investigate the effects of placebo and paranormal belief on the laterality of pain perception. The right hemisphere is dominantly involved in both the mediation of pain sensation and the belief in paranormal phenomena. We set out to assess a possible influence of long-term belief systems on placebo analgesia in response to unilateral nociceptive stimuli. Forty healthy participants (20 high and 20 low believers as indexed by the Magical Ideation Scale) underwent a placebo analgesia study measuring stimulus detection, pain threshold, and pain tolerance by electrostimulation on the right and left hand. Placebo treatment consisted of the application of a sham cream on the hands. Placebo had a positive influence on pain perception in the 3 variables. Enhanced pain sensitivity for the left side was only found for the disbelievers. Placebo treatment resulted in a double dissociation: in believers, it increased tolerance exclusively on the left side, in disbelievers on the right side. Our results confirm laterality effects in pain perception. However, only disbelievers conformed to the expected higher left-sided sensitivity. Placebo effects were dissociated between believers and disbelievers suggesting that short-term reactions to a placebo are modulated by a person's long-term belief system.

Do multiple body modifications alter pain threshold?

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Yamamotová, A; Hrabák, P; Hříbek, P; Rokyta, R

2017-12-30

In recent years, epidemiological data has shown an increasing number of young people who deliberately self-injure. There have also been parallel increases in the number of people with tattoos and those who voluntarily undergo painful procedures associated with piercing, scarification, and tattooing. People with self-injury behaviors often say that they do not feel the pain. However, there is no information regarding pain perception in those that visit tattoo parlors and piercing studios compared to those who don't. The aim of this study was to compare nociceptive sensitivity in four groups of subjects (n=105, mean age 26 years, 48 women and 57 men) with different motivations to experience pain (i.e., with and without multiple body modifications) in two different situations; (1) in controlled, emotionally neutral conditions, and (2) at a "Hell Party" (HP), an event organized by a piercing and tattoo parlor, with a main event featuring a public demonstration of painful techniques (burn scars, hanging on hooks, etc.). Pain thresholds of the fingers of the hand were measured using a thermal stimulator and mechanical algometer. In HP participants, information about alcohol intake, self-harming behavior, and psychiatric history were used in the analysis as intervening variables. Individuals with body modifications as well as without body modifications had higher thermal pain thresholds at Hell Party, compared to thresholds measured at control neutral conditions. No such differences were found relative to mechanical pain thresholds. Increased pain threshold in all HP participants, irrespectively of body modification, cannot be simply explained by a decrease in the sensory component of pain; instead, we found that the environment significantly influenced the cognitive and affective component of pain.

Feeling the pain of others is associated with self-other confusion and prior pain experience

OpenAIRE

Derbyshire, Stuart W. G.; Osborn, Jody; Brown, Steven

2013-01-01

Some chronic pain patients and healthy individuals experience pain when observing injury or others in pain. To further understand shared pain, we investigated perspective taking, bodily ownership and tooth pain sensitivity. First, participants who reported shared pain (responders) and those who did not (non-responders) viewed an avatar on a screen. Intermittently, 0-3 circles appeared. Sometimes the participant's and avatar's perspective were consistent, both directly viewed the same ...

A mouse model for chronic pain-induced increase in ethanol consumption.

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Butler, Ryan K; Knapp, Darin J; Ulici, Veronica; Longobardi, Lara; Loeser, Richard F; Breese, George R

2017-03-01

Chronic pain conditions are often comorbid with alcohol abuse. "Self-medication" with alcohol introduces a host of problems associated with the abuse of alcohol which over time has the potential of exacerbating the painful condition. Despite the prevalence of chronic pain being associated with alcohol abuse, rodent models which mimic the comorbid conditions are lacking. In this study, we model osteoarthritis (OA) in C57BL/6J mice by surgically destabilizing the medial meniscus (DMM). Sham-operated mice served as controls. Thirteen weeks after surgery, DMM but not sham-operated mice exhibited pronounced incapacitance of the surgically manipulated hind limb compared with the nonsurgically manipulated hind limb. At this time, the mice were exposed to the 2-bottle ethanol choice, beginning with 2.5% with a gradual increasing to 20%. Compared with sham controls, DMM mice consumed more EtOH and preferred EtOH over water at the 20% EtOH concentration. Histological analysis verified that the DMM mice exhibited significant damage to the articular cartilage and osteophyte growth compared with sham controls and these measures of the severity of OA correlated with the amount of ethanol intake. Thus, the combination of the DMM model of OA with the enhanced two-bottle ethanol choice is a potential preclinical approach in mice by which the basis of the comorbid association of alcohol abuse and chronic pain conditions can be explored.

Prediction of persistent post-surgery pain by preoperative cold pain sensitivity: biomarker development with machine-learning-derived analysis.

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Lötsch, J; Ultsch, A; Kalso, E

2017-10-01

To prevent persistent post-surgery pain, early identification of patients at high risk is a clinical need. Supervised machine-learning techniques were used to test how accurately the patients' performance in a preoperatively performed tonic cold pain test could predict persistent post-surgery pain. We analysed 763 patients from a cohort of 900 women who were treated for breast cancer, of whom 61 patients had developed signs of persistent pain during three yr of follow-up. Preoperatively, all patients underwent a cold pain test (immersion of the hand into a water bath at 2-4 °C). The patients rated the pain intensity using a numerical ratings scale (NRS) from 0 to 10. Supervised machine-learning techniques were used to construct a classifier that could predict patients at risk of persistent pain. Whether or not a patient rated the pain intensity at NRS=10 within less than 45 s during the cold water immersion test provided a negative predictive value of 94.4% to assign a patient to the "persistent pain" group. If NRS=10 was never reached during the cold test, the predictive value for not developing persistent pain was almost 97%. However, a low negative predictive value of 10% implied a high false positive rate. Results provide a robust exclusion of persistent pain in women with an accuracy of 94.4%. Moreover, results provide further support for the hypothesis that the endogenous pain inhibitory system may play an important role in the process of pain becoming persistent. © The Author 2017. Published by Oxford University Press on behalf of the British Journal of Anaesthesia.

Evaluation of Pain Assessment Techniques and Analgesia Efficacy in a Female Guinea Pig (Cavia porcellus) Model of Surgical Pain

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Oliver, Vanessa L; Athavale, Stephanie; Simon, Katherine E; Kendall, Lon V; Nemzek, Jean A; Lofgren, Jennifer L

2017-01-01

Guinea pigs (Cavia porcellus) are a frequently used species in research, often involving potentially painful procedures. Therefore, evidence-based recommendations regarding analgesia are critically needed to optimize their wellbeing. Our laboratory examined the efficacy of carprofen and extended-release (ER) buprenorphine, alone and as a multimodal combination, for relieving postsurgical pain in guinea pigs. Animals were assessed by using evoked (mechanical hypersensitivity), nonevoked (video ethogram, cageside ethogram, time-to-consumption test), and clinical (weight loss) measurements for 96 h during baseline, anesthesia–analgesia, and hysterectomy conditions. In addition, ER buprenorphine was evaluated pharmacologically. Guinea pigs treated with a single analgesic showed increased mechanical sensitivity for at least 96 h and indices of pain according to the video ethogram for as long as 8 h, compared with levels recorded during anesthesia–analgesia. In contrast, animals given both analgesics demonstrated increased mechanical sensitivity and behavioral evidence of pain for only 2 h after surgery compared with anesthesia–analgesia. The cageside ethogram and time-to-consumption tests failed to identify differences between conditions or treatment groups, highlighting the difficulty of identifying pain in guinea pigs without remote observation. Guinea pigs treated with multimodal analgesia or ER buprenorphine lost at least 10% of their baseline weights, whereas weight loss in carprofen animals was significantly lower (3%). Plasma levels for ER buprenorphine exceeded 0.9 ng/mL from 8 to 96 h after injection. Of the 3 analgesia regimens evaluated, multimodal analgesia provided the most effective pain control in guinea pigs. However the weight loss in the ER buprenorphine–treated animals may need to be considered during analgesia selection. PMID:28724492

Anorectal and Pelvic Pain.

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Bharucha, Adil E; Lee, Tae Hee

2016-10-01

Although pelvic pain is a symptom of several structural anorectal and pelvic disorders (eg, anal fissure, endometriosis, and pelvic inflammatory disease), this comprehensive review will focus on the 3 most common nonstructural, or functional, disorders associated with pelvic pain: functional anorectal pain (ie, levator ani syndrome, unspecified anorectal pain, and proctalgia fugax), interstitial cystitis/bladder pain syndrome, and chronic prostatitis/chronic pelvic pain syndrome. The first 2 conditions occur in both sexes, while the latter occurs only in men. They are defined by symptoms, supplemented with levator tenderness (levator ani syndrome) and bladder mucosal inflammation (interstitial cystitis). Although distinct, these conditions share several similarities, including associations with dysfunctional voiding or defecation, comorbid conditions (eg, fibromyalgia, depression), impaired quality of life, and increased health care utilization. Several factors, including pelvic floor muscle tension, peripheral inflammation, peripheral and central sensitization, and psychosocial factors, have been implicated in the pathogenesis. The management is tailored to symptoms, is partly supported by clinical trials, and includes multidisciplinary approaches such as lifestyle modifications and pharmacological, behavioral, and physical therapy. Opioids should be avoided, and surgical treatment has a limited role, primarily in refractory interstitial cystitis. Copyright © 2016 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.

Increasing sensitivity of MOS dosemeters in cascade connection

International Nuclear Information System (INIS)

Vychytil, F.; Cechak, T.; Gerndt, J.; Petr, I.

1978-01-01

The possibilities of increasing the sensitivity of MOS transistors in their cascade connection were studied theoretically and experimentally. The measurements confirmed the presumption that the instability of cascade-connected MOS transistors increased with the square of the number of transistors in the system. This allows systems to be formed with different sensitivity to ionizing radiation by encasing 10 to 10 4 transistors connected in cascade, which is technologically feasible. The procedure is also acceptable from the point of view of cost. (Z.M.)

Pain and other symptoms of CRPS can be increased by ambiguous visual stimuli--an exploratory study.

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Hall, Jane; Harrison, Simon; Cohen, Helen; McCabe, Candida S; Harris, N; Blake, David R

2011-01-01

Visual disturbance, visuo-spatial difficulties, and exacerbations of pain associated with these, have been reported by some patients with Complex Regional Pain Syndrome (CRPS). We investigated the hypothesis that some visual stimuli (i.e. those which produce ambiguous perceptions) can induce pain and other somatic sensations in people with CRPS. Thirty patients with CRPS, 33 with rheumatology conditions and 45 healthy controls viewed two images: a bistable spatial image and a control image. For each image participants recorded the frequency of percept change in 1 min and reported any changes in somatosensation. 73% of patients with CRPS reported increases in pain and/or sensory disturbances including changes in perception of the affected limb, temperature and weight changes and feelings of disorientation after viewing the bistable image. Additionally, 13% of the CRPS group responded with striking worsening of their symptoms which necessitated task cessation. Subjects in the control groups did not report pain increases or somatic sensations. It is possible to worsen the pain suffered in CRPS, and to produce other somatic sensations, by means of a visual stimulus alone. This is a newly described finding. As a clinical and research tool, the experimental method provides a means to generate and exacerbate somaesthetic disturbances, including pain, without moving the affected limb and causing nociceptive interference. This may be particularly useful for brain imaging studies. Copyright © 2010 European Federation of International Association for the Study of Pain Chapters. Published by Elsevier Ltd. All rights reserved.

Sleep fragmentation exacerbates mechanical hypersensitivity and alters subsequent sleep-wake behavior in a mouse model of musculoskeletal sensitization.

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Sutton, Blair C; Opp, Mark R

2014-03-01

Sleep deprivation, or sleep disruption, enhances pain in human subjects. Chronic musculoskeletal pain is prevalent in our society, and constitutes a tremendous public health burden. Although preclinical models of neuropathic and inflammatory pain demonstrate effects on sleep, few studies focus on musculoskeletal pain. We reported elsewhere in this issue of SLEEP that musculoskeletal sensitization alters sleep of mice. In this study we hypothesize that sleep fragmentation during the development of musculoskeletal sensitization will exacerbate subsequent pain responses and alter sleep-wake behavior of mice. This is a preclinical study using C57BL/6J mice to determine the effect on behavioral outcomes of sleep fragmentation combined with musculoskeletal sensitization. Musculoskeletal sensitization, a model of chronic muscle pain, was induced using two unilateral injections of acidified saline (pH 4.0) into the gastrocnemius muscle, spaced 5 days apart. Musculoskeletal sensitization manifests as mechanical hypersensitivity determined by von Frey filament testing at the hindpaws. Sleep fragmentation took place during the consecutive 12-h light periods of the 5 days between intramuscular injections. Electroencephalogram (EEG) and body temperature were recorded from some mice at baseline and for 3 weeks after musculoskeletal sensitization. Mechanical hypersensitivity was determined at preinjection baseline and on days 1, 3, 7, 14, and 21 after sensitization. Two additional experiments were conducted to determine the independent effects of sleep fragmentation or musculoskeletal sensitization on mechanical hypersensitivity. Five days of sleep fragmentation alone did not induce mechanical hypersensitivity, whereas sleep fragmentation combined with musculoskeletal sensitization resulted in prolonged and exacerbated mechanical hypersensitivity. Sleep fragmentation combined with musculoskeletal sensitization had an effect on subsequent sleep of mice as demonstrated by increased

Increasing Optimism Protects Against Pain-Induced Impairment in Task-Shifting Performance.

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Boselie, Jantine J L M; Vancleef, Linda M G; Peters, Madelon L

2017-04-01

Persistent pain can lead to difficulties in executive task performance. Three core executive functions that are often postulated are inhibition, updating, and shifting. Optimism, the tendency to expect that good things happen in the future, has been shown to protect against pain-induced performance deterioration in executive function updating. This study tested whether this protective effect of a temporary optimistic state by means of a writing and visualization exercise extended to executive function shifting. A 2 (optimism: optimism vs no optimism) × 2 (pain: pain vs no pain) mixed factorial design was conducted. Participants (N = 61) completed a shifting task once with and once without concurrent painful heat stimulation after an optimism or neutral manipulation. Results showed that shifting performance was impaired when experimental heat pain was applied during task execution, and that optimism counteracted pain-induced deterioration in task-shifting performance. Experimentally-induced heat pain impairs shifting task performance and manipulated optimism or induced optimism counteracted this pain-induced performance deterioration. Identifying psychological factors that may diminish the negative effect of persistent pain on the ability to function in daily life is imperative. Copyright © 2016 American Pain Society. Published by Elsevier Inc. All rights reserved.

Increasing Neuroplasticity to Bolster Chronic Pain Treatment: A Role for Intermittent Fasting and Glucose Administration?

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Sibille, Kimberly T; Bartsch, Felix; Reddy, Divya; Fillingim, Roger B; Keil, Andreas

2016-03-01

Neuroplastic changes in brain structure and function are not only a consequence of chronic pain but are involved in the maintenance of pain symptoms. Thus, promotion of adaptive, treatment-responsive neuroplasticity represents a promising clinical target. Emerging evidence about the human brain's response to an array of behavioral and environmental interventions may assist in identifying targets to facilitate increased neurobiological receptivity, promoting healthy neuroplastic changes. Specifically, strategies to maximize neuroplastic responsiveness to chronic pain treatment could enhance treatment gains by optimization of learning and positive central nervous system adaptation. Periods of heightened plasticity have been traditionally identified with the early years of development. More recent research, however, has identified a wide spectrum of methods that can be used to "reopen" and enhance plasticity and learning in adults. In addition to transcranial direct current stimulation and transcranial magnetic stimulation, behavioral and pharmacological interventions have been investigated. Intermittent fasting and glucose administration are two propitious strategies, that are noninvasive, inexpensive to administer, implementable in numerous settings, and might be applicable across differing chronic pain treatments. Key findings and neurophysiological mechanisms are summarized, and evidence for the potential clinical contributions of these two strategies toward ameliorating chronic pain is presented. Neuroplastic changes are a defining feature of chronic pain and a complicating factor in treatment. Noninvasive strategies to optimize the brain's response to treatment interventions might improve learning and memory, increase the positive adaptability of the central nervous system, and enhance treatment outcomes. Copyright © 2016 American Pain Society. Published by Elsevier Inc. All rights reserved.

Accuracy of a Diagnostic Algorithm to Diagnose Breakthrough Cancer Pain as Compared With Clinical Assessment.

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Webber, Katherine; Davies, Andrew N; Cowie, Martin R

2015-10-01

Breakthrough cancer pain (BTCP) is a heterogeneous condition, and there are no internationally agreed standardized criteria to diagnose it. There are published algorithms to assist with diagnosis, but these differ in content. There are no comparative data to support use. To compare the diagnostic ability of a simple algorithm against a comprehensive clinical assessment to diagnose BTCP and to assess if verbal rating descriptors can adequately discriminate controlled background pain. Patients with cancer pain completed a three-step algorithm with a researcher to determine if they had controlled background pain and BTCP. This was followed by a detailed pain consultation with a clinical specialist who was blinded to the algorithm results and determined an independent pain diagnosis. The sensitivity, specificity, and positive and negative predictive values were calculated for the condition of BTCP. Further analysis determined which verbal pain severity descriptors corresponded with the condition of controlled background pain. The algorithm had a sensitivity of 0.54 and a specificity of 0.76 in the identification of BTCP. The positive predictive value was 0.7, and the negative predictive value was 0.62. The sensitivity of a background pain severity rating of mild or less to accurately categorize controlled background pain was 0.69 compared with 0.97 for severity of moderate or less; however, this was balanced by a higher specificity rating for mild or less, 0.78 compared with 0.2. The diagnostic breakthrough pain algorithm had a good positive predictive value but limited sensitivity using a cutoff score of "mild" to define controlled background pain. When the cutoff level was changed to moderate, the sensitivity increased, but specificity reduced. A comprehensive clinical assessment remains the preferred method to diagnose BTCP. Copyright © 2015 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.

Cold hypersensitivity increases with age in mice with sickle cell disease

Science.gov (United States)

Zappia, Katherine J.; Garrison, Sheldon R.; Hillery, Cheryl A.; Stucky, Cheryl L.

2014-01-01

Sickle cell disease (SCD) is associated with acute vaso-occlusive crises that trigger painful episodes and frequently involves ongoing, chronic pain. Additionally, both humans and mice with SCD experience heighted cold sensitivity. However, studies have not addressed the mechanism(s) underlying the cold sensitization, nor its progression with age. Here we measured thermotaxis behavior in young and aged mice with severe SCD. Sickle mice had a marked increase in cold sensitivity measured by a cold preference test. Further, cold hypersensitivity worsened with advanced age. We assessed whether enhanced peripheral input contributes to the chronic cold pain behavior by recording from C fibers, many of which are cold-sensitive, in skin-nerve preparations. We observed that C fibers from sickle mice displayed a shift to warmer (more sensitive) cold-detection thresholds. To address mechanisms underlying the cold sensitization in primary afferent neurons, we quantified mRNA expression levels for ion channels thought to be involved in cold detection. These included the Transient Receptor Potential Melastatin 8 (Trpm8) and TRP Ankyrin 1 (Trpa1) channels, as well as the two-pore domain potassium channels, TREK-1 (Kcnk2), TREK-2 (Kcnk4), and TRAAK (Kcnk10). Surprisingly, transcript expression levels of all of these channels were comparable between sickle and control mice. We further examined transcript expression of 83 additional pain-related genes and found increased mRNA levels for endothelin 1 and tachykinin receptor 1. These factors may contribute to hypersensitivity in sickle mice at both the afferent and behavioral levels. Sensory neurons from sickle cell disease mice are sensitized to cold, mirroring behavioral observations, and have increased expression of endothelin 1 and tachykinin receptor 1. PMID:24953902

The contribution of spinal glial cells to chronic pain behaviour in the monosodium iodoacetate model of osteoarthritic pain

Directory of Open Access Journals (Sweden)

Sagar Devi

2011-11-01

Full Text Available Abstract Background Clinical studies of osteoarthritis (OA suggest central sensitization may contribute to the chronic pain experienced. This preclinical study used the monosodium iodoacetate (MIA model of OA joint pain to investigate the potential contribution of spinal sensitization, in particular spinal glial cell activation, to pain behaviour in this model. Experimental OA was induced in the rat by the intra-articular injection of MIA and pain behaviour (change in weight bearing and distal allodynia was assessed. Spinal cord microglia (Iba1 staining and astrocyte (GFAP immunofluorescence activation were measured at 7, 14 and 28 days post MIA-treatment. The effects of two known inhibitors of glial activation, nimesulide and minocycline, on pain behaviour and activation of microglia and astrocytes were assessed. Results Seven days following intra-articular injection of MIA, microglia in the ipsilateral spinal cord were activated (p Conclusions Here we provide evidence for a contribution of spinal glial cells to pain behaviour, in particular distal allodynia, in this model of osteoarthritic pain. Our data suggest there is a potential role of glial cells in the central sensitization associated with OA, which may provide a novel analgesic target for the treatment of OA pain.

Increased circulating rather than spinal cytokines accompany chronic pain behaviors in experimental bone cancer and arthritis

Directory of Open Access Journals (Sweden)

Line Pourtau

2014-12-01

Full Text Available Aim: Peripheral cytokines contribute to arthritis and bone cancer pain through sensory nerve actions. However, increased spinal cytokine and glial filament expression, coined neuroinflammation, has also been proposed to play a part in chronic pain. Therefore, spinal cord, dorsal root ganglia and circulating cytokines were compared in murine arthritis and bone cancer models in relationship to behavioral signs of pain. Methods: Exploratory behaviors were studied after intra-articular complete Freund's adjuvant or bone intramedullary sarcoma cell injection. Nervous tissue and blood cytokine expression were determined by real-time polymerase chain reaction (PCR and multiplex immunoassays, respectively. Results: PCR analysis did not reveal any hallmark of spinal neuroinflammation in spontaneously-behaving mice with cartilage or bone lesions. However, imposed paw stimulation during joint inflammation increased spinal interleukin-1β (IL-1β expression. Spontaneous paw guarding during rearing was displayed by animals with joint inflammation and bone destruction and was accompanied by increased circulating IL-6 and monocyte chemoattractant protein-1, respectively. In addition, dorsal root ganglia were found to constitutively express receptors for this chemotactic cytokine. Conclusion: Our findings indicate that spinal neuroinflammation is not a necessary condition for chronic pain and suggest that circulating cytokine action in dorsal root ganglia may contribute to experimental joint inflammation and bone cancer pain.

The Methanolic Extract from Murraya koenigii L. Inhibits Glutamate-Induced Pain and Involves ATP-Sensitive K+ Channel as Antinociceptive Mechanism

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Nushrat Sharmin Ani

2016-01-01

Full Text Available Murraya koenigii L. is a perennial shrub, belonging to the family Rutaceae. Traditionally, the leaves of this plant are extensively used in treatment of a wide range of diseases and disorders including pain and inflammation. Although researchers have revealed the antinociceptive effects of this plant’s leaves during past few years, the mechanisms underlying these effects are still unknown. Therefore, the present study evaluated some antinociceptive mechanisms of the methanolic extract of M. koenigii (MEMK leaves along with its antinociceptive potential using several animal models. The antinociceptive effects of MEMK were evaluated using formalin-induced licking and acetic acid-induced writhing tests at the doses of 50, 100, and 200 mg/kg. In addition, we also justified the possible participations of glutamatergic system and ATP-sensitive potassium channels in the observed activities. Our results demonstrated that MEMK significantly (p<0.01 inhibited the pain thresholds induced by formalin and acetic acid in a dose-dependent manner. MEMK also significantly (p<0.01 suppressed glutamate-induced pain. Moreover, pretreatment with glibenclamide (an ATP-sensitive potassium channel blocker at 10 mg/kg significantly (p<0.05 reversed the MEMK-mediated antinociception. These revealed that MEMK might have the potential to interact with glutamatergic system and the ATP-sensitive potassium channels to exhibit its antinociceptive activities. Therefore, our results strongly support the antinociceptive effects of M. koenigii leaves and provide scientific basis of their analgesic uses in the traditional medicine.