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Nastaj J, Skalski J, Budzisz A, Szikszay TM, Swoboda S, Kowalska W, Nowak D, Zbroja E, Kruszyna N, Jakubińska M, Grygny D, Polczyk R, Małecki A, Luedtke K, Adamczyk WM. Spatial summation of pain is associated with pain expectations: Results from a home-based paradigm. PLoS One 2024; 19:e0297067. [PMID: 38300918 PMCID: PMC10833545 DOI: 10.1371/journal.pone.0297067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Accepted: 12/23/2023] [Indexed: 02/03/2024] Open
Abstract
The purpose of this study was to reproduce the previously observed spatial summation of pain effect (SSp) using non-laboratory procedures and commercial equipment. An additional aim was to explore the association between expectations and SSp. The Cold Pressor Task (CPT) was used to induce SSp. Healthy participants (N = 68) immersed their non-dominant hands (divided into 5 segments) into cold water (CPT). Two conditions were used 1) gradual hand immersion (ascending condition) and 2) gradual hand withdrawal (descending condition). Pain intensity was measured on a Visual Analogue Scale (VAS). Psychological factors, such as the participants' expectations of pain intensity were also measured on a VAS. Results showed significant SSp (χ2(4) = 116.90, p < 0.001), reproduced with non-laboratory equipment in a home-based set-up. Furthermore, two novel findings were observed: i) there was a significant correlation between expectations and perceived pain, indicating a link between pain expectations and SSp, ii) spatial summation increased with the increase in duration exposure to the noxious stimulus (Wald χ2(8) = 80.80, p < 0.001). This study suggests that SSp is associated with pain expectations and can be formed by a mixture of excitatory and inhibitory mechanisms potentially driven by temporal characteristics of neural excitation. Moreover, this study proposes a new feasible way to induce SSp using a home-based set-up.
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Affiliation(s)
- Jakub Nastaj
- Laboratory of Pain Research, Institute of Physiotherapy and Health Science, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
| | - Jacek Skalski
- Laboratory of Pain Research, Institute of Physiotherapy and Health Science, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
| | - Aleksandra Budzisz
- Laboratory of Pain Research, Institute of Physiotherapy and Health Science, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
| | - Tibor M. Szikszay
- Institute of Health Sciences, Department of Physiotherapy, Pain & Exercise Research Lübeck, Universität zu Lübeck, Lübeck, Germany
| | - Sylwia Swoboda
- Laboratory of Pain Research, Institute of Physiotherapy and Health Science, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
| | - Weronika Kowalska
- Laboratory of Pain Research, Institute of Physiotherapy and Health Science, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
| | - Daria Nowak
- Laboratory of Pain Research, Institute of Physiotherapy and Health Science, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
| | - Edyta Zbroja
- Laboratory of Pain Research, Institute of Physiotherapy and Health Science, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
| | - Natalia Kruszyna
- Laboratory of Pain Research, Institute of Physiotherapy and Health Science, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
| | - Marta Jakubińska
- Laboratory of Pain Research, Institute of Physiotherapy and Health Science, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
| | - Dominika Grygny
- Laboratory of Pain Research, Institute of Physiotherapy and Health Science, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
| | - Romuald Polczyk
- Institute of Psychology, Jagiellonian University, Kraków, Poland
| | - Andrzej Małecki
- Laboratory of Pain Research, Institute of Physiotherapy and Health Science, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
| | - Kerstin Luedtke
- Institute of Health Sciences, Department of Physiotherapy, Pain & Exercise Research Lübeck, Universität zu Lübeck, Lübeck, Germany
| | - Wacław M. Adamczyk
- Laboratory of Pain Research, Institute of Physiotherapy and Health Science, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
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Pain is Not a "thing": How That Error Affects Language and Logic in Pain Medicine. THE JOURNAL OF PAIN 2022; 23:1283-1293. [PMID: 35427806 DOI: 10.1016/j.jpain.2022.03.235] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 03/08/2022] [Accepted: 03/17/2022] [Indexed: 02/06/2023]
Abstract
Effectiveness in academic and clinical communication depends upon agreement on what words and concepts denote and on the consequent ability to argue logically and accurately. In the pain medicine literature there are many examples of imprecision and confusion in this respect, including misnomers and fallacies in reasoning. This article firstly critically examines some of these misnomers. Identified themes include pain being conceptualised as a "thing," conflation between nociception and pain, and confusion between stimulus and response and between the perspectives of the experiencer and the observer of "pain." Secondly, fallacies in reasoning are identified that contribute to imprecision and confusion. These include reification of pain, attributing to the brain functions that belong to whole organisms, and the illusory truth effect. Thirdly, these themes are identified also in constructs that are shown to be based more on speculation than on fact. Taken together, these observations reveal a need to review and, where necessary, modify terminology and concepts used in Pain Medicine. PERSPECTIVE: This article examines a number of words and constructs commonly found in the pain literature from the perspective of accuracy in terms of their consistency of usage, concordance with fact, degree of speculation and logical argument. A common major theme is the error of considering pain as a "thing" that has agentive properties. A need to clarify much of the language used in Pain Medicine is identified.
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Behrens R, Pliske G, Umbreit M, Piatek S, Walcher F, Elkmann N. A Statistical Model to Determine Biomechanical Limits for Physically Safe Interactions With Collaborative Robots. Front Robot AI 2022; 8:667818. [PMID: 35187090 PMCID: PMC8850785 DOI: 10.3389/frobt.2021.667818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 11/23/2021] [Indexed: 11/13/2022] Open
Abstract
Collaborative robots (cobots) provide a wide range of opportunities to improve the ergonomics and efficiency of manual work stations. ISO/TS 15066 defines power and force limiting (PFL) as one of four safeguarding modes for these robots. PFL specifies biomechanical limits for hazardous impacts and pinching contacts that a cobot must not exceed to protect humans from serious injuries. Most of the limits in ISO/TS 15066 are preliminary, since they are based on unverified data from a literature survey. This article presents a human-subject study that provides new and experimentally verified limits for biomechanically safe interactions between humans and cobots. The new limits are specifically tailored to impact and pinching transferred through blunt and semi-sharp surfaces as they can occur in the event of human error or technical failures. Altogether 112 subjects participated in the study and were subjected to tests with emulated impact and pinching loads at 28 different body locations. During the experiments, the contact force was gradually increased until the load evoked a slightly painful feeling on the subject’s body location under test. The results confirm that the pain thresholds of males and females are different in specific body regions. Therefore, when defining biomechanical limits, the gender difference must be taken into account. A regression model was utilized to incorporate the gender effect as a covariate into a conventional statistical distribution model that can be used to calculate individual limits, precisely fitted to a specific percentile of a mixed group of male and female workers which interacting with cobots.
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Affiliation(s)
- R. Behrens
- Robotic Systems, Fraunhofer IFF, Magdeburg, Germany
- *Correspondence: R. Behrens ,
| | - G. Pliske
- Department of Trauma Surgery, Otto von Guericke University, Magdeburg, Germany
| | | | - S. Piatek
- Department of Trauma Surgery, Otto von Guericke University, Magdeburg, Germany
| | - F. Walcher
- Department of Trauma Surgery, Otto von Guericke University, Magdeburg, Germany
| | - N. Elkmann
- Robotic Systems, Fraunhofer IFF, Magdeburg, Germany
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Henrich MC, Frahm KS, Andersen OK. Spinal spatial integration of nociception and its functional role assessed via the nociceptive withdrawal reflex and psychophysical measures in healthy humans. Physiol Rep 2021; 8:e14648. [PMID: 33217191 PMCID: PMC7679129 DOI: 10.14814/phy2.14648] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 10/20/2020] [Accepted: 10/23/2020] [Indexed: 12/11/2022] Open
Abstract
Animal studies have previously shown that deep dorsal horn neurons play a role in the processing of spatial characteristics of nociceptive information in mammals. Human studies have supported the role of the spinal neurons; however, the mechanisms involved, and its significance, remain to be clarified. The aim of this study was to investigate spatial aspects of the spinal integration of concurrent nociceptive electrical stimuli in healthy humans using the Nociceptive Withdrawal Reflex (NWR) as an objective indication of spinal nociceptive processing. Fifteen healthy volunteers participated in the study. Electrical stimuli were delivered, using five electrodes located across the sole of the foot in a mediolateral disposition, as a single or double simultaneous stimuli with varying Inter-Electrode Distances (IEDs). The stimulation intensity was set at 1.5× NWR threshold (TA muscle). The size of the NWR was quantified in the 60-180 ms poststimulus window as a primary outcome measure. Psychophysical measures were secondary outcomes. Single stimulation elicited significantly smaller NWRs and perceived intensity than double stimulation (p < .01), suggesting the presence of spatial summation occurring within the spinal processing. During double stimulation, increasing the inter-electrode distance produced significantly smaller NWR sizes (p < .05) but larger pain intensity ratings (p < .05). By the NWR, spatial summation was shown to affect the nociceptive processing within the spinal cord. The inhibited motor response obtained when simultaneously stimulating the medial and lateral side of the sole of the foot suggests the presence of an inhibitory mechanism with a functional, behaviorally oriented function.
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Affiliation(s)
- Mauricio Carlos Henrich
- Integrative Neuroscience, Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Aalborg University, Aalborg Ø, Denmark
| | - Ken Steffen Frahm
- Integrative Neuroscience, Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Aalborg University, Aalborg Ø, Denmark
| | - Ole Kaeseler Andersen
- Integrative Neuroscience, Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Aalborg University, Aalborg Ø, Denmark
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Henrich MC, Frahm KS, Andersen OK. Tempo-spatial integration of nociceptive stimuli assessed via the nociceptive withdrawal reflex in healthy humans. J Neurophysiol 2021; 126:373-382. [PMID: 34191609 DOI: 10.1152/jn.00155.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Spatial information of nociceptive stimuli applied in the skin of healthy humans is integrated in the spinal cord to determine the appropriate withdrawal reflex response. Double-simultaneous stimulus applied in different skin sites are integrated, eliciting a larger reflex response. The temporal characteristics of the stimuli also modulate the reflex, e.g., by temporal summation. The primary aim of this study was to investigate how the combined tempo-spatial aspects of two stimuli are integrated in the nociceptive system. This was investigated by delivering single- and double-simultaneous stimulation and sequential stimulation with different interstimulus intervals (ISIs ranging 30-500 ms) to the sole of the foot of 15 healthy subjects. The primary outcome measure was the size of the nociceptive withdrawal reflex (NWR) recorded from the tibialis anterior (TA) and biceps femoris (BF) muscles. Pain intensity was measured using a numerical rating scale (NRS) scale. Results showed spatial summation in both TA and BF when delivering simultaneous stimulation. Simultaneous stimulation provoked larger reflexes than sequential stimulation in TA, but not in BF. Larger ISIs elicited significantly larger reflexes in TA, whereas the opposite pattern occurred in BF. This differential modulation between proximal and distal muscles suggests the presence of spinal circuits eliciting a functional reflex response based on the specific tempo-spatial characteristics of a noxious stimulus. No modulation was observed in pain intensity ratings across ISIs. Absence of modulation in the pain intensity ratings argues for an integrative mechanism located within the spinal cord governed by a need for efficient withdrawal from a potentially harmful stimulus.NEW & NOTEWORTHY Tempo-spatial integration of electrical noxious stimuli was studied using the nociceptive withdrawal reflex and a perceived intensity. Tibialis anterior and biceps femoris muscles were differentially modulated by the temporal characteristics of the stimuli and stimulated sites. These findings suggest that spinal neurons are playing an important role in the tempo-spatial integration of nociceptive information, leading to a reflex response that is distributed across multiple spinal cord segments and governed by an efficient defensive withdrawal strategy.
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Affiliation(s)
- Mauricio Carlos Henrich
- Integrative Neuroscience, Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Ken Steffen Frahm
- Integrative Neuroscience, Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Ole Kæseler Andersen
- Integrative Neuroscience, Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
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Nonlinear increase of pain in distance-based and area-based spatial summation. Pain 2021; 162:1771-1780. [PMID: 33449502 DOI: 10.1097/j.pain.0000000000002186] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 12/30/2020] [Indexed: 11/25/2022]
Abstract
ABSTRACT When nociceptive stimulation affects a larger body area, pain increases. This effect is called spatial summation of pain (SSp). The aim of this study was to describe SSp as a function of the size or distance of a stimulated area(s) and to test how this function is shaped by the intensity and SSp test paradigm. Thirty-one healthy volunteers participated in a within-subject experiment. Participants were exposed to area-based and distanced-based SSp. For area-based SSp, electrocutaneous noxious stimuli were applied by up to 5 electrodes (5 areas) forming a line-like pattern; for distance-based SSp, the same position and lengths of stimuli were used but only 2 electrodes were stimulated. Each paradigm was repeated using pain of low, moderate, and high intensity. It was found that the pattern of pain intensity followed a logarithmic (power) rather than a linear function. The dynamics of the pain increase were significantly different across pain intensities, with more summation occurring when pain was perceived as low. Results indicated that area-based SSp is more painful than distance-based SSp when low and moderate but not when high pain intensity is induced. Presented findings have important implications for all studies in which the spatial dimension of pain is measured. When the area or separation between nociceptive stimulation increases, pain does not increase linearly and the pattern of the pain increase is a result of the interaction between intensity and the number of nociceptive sites. A power function should be considered when predicting the size of a nociceptive source.
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Adamczyk WM, Szikszay TM, Kung T, Carvalho GF, Luedtke K. Not as "blurred" as expected? Acuity and spatial summation in the pain system. Pain 2021; 162:794-802. [PMID: 32925592 PMCID: PMC7920491 DOI: 10.1097/j.pain.0000000000002069] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 08/27/2020] [Accepted: 08/28/2020] [Indexed: 11/27/2022]
Abstract
ABSTRACT Spatial acuity measured by 2-point discrimination (2PD) threshold and spatial summation of pain (SSp) are useful paradigms to probe the pain system in humans. Whether the results of these paradigms are influenced by different stimulus modalities and intensities is unclear. The aim of this study was to test 2PD controlling the stimulus modality and the intensity and to investigate the effect of modality on SSp. Thirty-seven healthy volunteers were tested for 2PDs with 2 stimulus modalities (electrocutaneous and mechanical) and intensity (noxious and innocuous). For each condition, participants received stimuli to either 1 or 2 points on their lower back with different distances (2-14 cm, steps of 2 cm). It was found that 2PDs were significantly smaller for noxious stimuli for both modalities. By contrast, between-modality comparison reproduced previous reports of impaired acuity for noxious stimulation. Higher pain intensities were reported when a larger area was stimulated (SSp), independent of the modality. Furthermore, reported pain intensities were higher when the distance between 2 stimulated areas was increased from 2 to 6 cm (P < 0.001), 8 cm (P < 0.01), and 14 cm (P < 0.01). 2PDs determined by mechanical and electrocutaneous stimuli were significantly correlated within both stimulus intensities, ie, innocuous (r = 0.34, P < 0.05) and noxious (r = 0.35, P < 0.05). The current results show 3 novel findings: (1) the precision of the pain system might be higher than in the innocuous (tactile) system when mechanical and electrocutaneous modalities are used, (2) the pattern of distance-based and area-based SSp seems to be comparable irrespective of the modality applied (mechanical and electrocutaneous), and (3) both modalities are moderately correlated.
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Affiliation(s)
- Wacław M. Adamczyk
- Department of Health Sciences, Academic Physiotherapy, Pain and Exercise Research Luebeck (P.E.R.L.), University of Luebeck, Luebeck, Germany
- Center of Brain, Behavior and Metabolism (CBBM), University of Luebeck, Luebeck, Germany
- Laboratory of Pain Research, Institute of Physiotherapy and Health Sciences, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
| | - Tibor M. Szikszay
- Department of Health Sciences, Academic Physiotherapy, Pain and Exercise Research Luebeck (P.E.R.L.), University of Luebeck, Luebeck, Germany
- Center of Brain, Behavior and Metabolism (CBBM), University of Luebeck, Luebeck, Germany
| | - Tiffany Kung
- BSc Study Program, University of Alberta, Edmonton, AB, Canada
| | | | - Kerstin Luedtke
- Department of Health Sciences, Academic Physiotherapy, Pain and Exercise Research Luebeck (P.E.R.L.), University of Luebeck, Luebeck, Germany
- Center of Brain, Behavior and Metabolism (CBBM), University of Luebeck, Luebeck, Germany
- Laboratory of Pain Research, Institute of Physiotherapy and Health Sciences, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
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Hand-held dynamometer to measure pressure pain thresholds: A double-blinded reliability and validity study. Musculoskelet Sci Pract 2021; 51:102268. [PMID: 33023868 DOI: 10.1016/j.msksp.2020.102268] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 09/04/2020] [Accepted: 09/28/2020] [Indexed: 01/31/2023]
Abstract
BACKGROUND Pain is the most common complaint reported in the musculoskeletal setting. Quantitative sensory testing (QST) assists with pain mechanism identification, although QST is typically performed in research settings. It is possible that clinical utilization of QST may improve if clinically accessible tools can be reliably and validly used. OBJECTIVE To determine if a hand-held dynamometer (HHD) can be a valid and reliable assessment of pressure pain threshold (PPT). DESIGN Double-blinded validation study. METHODS Eighteen healthy subjects (25.6 ± 3.4 years old) participated in this study. Two testers independently assessed PPT using a HHD and a digital algometer. Assessments followed previously described pressure algometry protocols. Testers and subjects were each blinded to data during assessments. RESULTS Intra- and inter-rater reliability were excellent for the foot and face for both devices (ICC's > 0.9). Bland-Altman plots and intraclass correlation coefficients revealed good-excellent agreement with minimal proportional bias when normalizing device force at pain threshold to the circumference of the device applicator (ICC 95%CI: 0.56-0.95). Only poor-good agreement (ICC 95% CI: 0.30-0.76) and significant proportional bias was observed when normalizing to area (pressure). CONCLUSIONS Based on the results of this study, when force is normalized by circumference of the applicator, a HHD was found to be a valid and reliable tool for measuring PPT. Clinicians may use HHD to detect relevant pain mechanisms at fault in their evaluation and treatment of pain. Additional research in various pathologic populations is warranted.
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Levy D, Gruener H, Riabinin M, Feingold Y, Schreiber S, Pick CG, Defrin R. Different clinical phenotypes of persistent post-traumatic headache exhibit distinct sensory profiles. Cephalalgia 2020; 40:675-688. [PMID: 31847569 PMCID: PMC10589814 DOI: 10.1177/0333102419896368] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2023]
Abstract
INTRODUCTION Persistent post-traumatic headache remains a poorly understood clinical entity. Although there are currently no accepted therapies for persistent post-traumatic headache, its clinical symptoms, which primarily resemble those of migraine or tension-type headache, often serve to guide treatment. However, evidence-based justification for this treatment approach remains lacking given the paucity of knowledge regarding the characteristics of these two major persistent post-traumatic headache phenotypes and their etiology. METHODS We compared clinical features and quantitative sensory testing profiles between two distinct cohorts of persistent post-traumatic headache subjects that exhibited symptoms resembling either migraine (n = 15) or tension-type headache (n = 13), as well as to headache-free subjects that had suffered traumatic brain injury (n = 19), and to healthy controls (n = 10). We aimed to determine whether the two persistent post-traumatic headache subgroups could be discriminated based on additional clinical features, distinct quantitative sensory testing profiles, or the interaction of pain severity with the level of post-traumatic stress disorder. RESULTS Persistent post-traumatic headache subjects with migraine-like symptoms reported that bright light and focused attention aggravated their pain, while stress and nervousness were reported to aggravate the headache in subjects with tension-type headache-like symptoms. Quietness was better in alleviating migraine-like persistent post-traumatic headache, while anti-inflammatory medications provided better relief in tension-type headache-like persistent post-traumatic headache. The two persistent post-traumatic headache subgroups exhibited distinct quantitative sensory testing profiles with subjects exhibiting tension-type headache-like persistent post-traumatic headache displaying a more pronounced cephalic and extracephalic thermal hypoalgesia that was accompanied by cephalic mechanical hyperalgesia. While both persistent post-traumatic headache subgroups had high levels of post-traumatic stress disorder, there was a positive correlation with pain severity in subjects with tension-type headache-like symptoms, but a negative correlation in subjects with migraine-like symptoms. CONCLUSIONS Distinct persistent post-traumatic headache symptoms and quantitative sensory testing profiles may be linked to different etiologies, potentially involving various levels of neuropathic and inflammatory pain, and if confirmed in a larger cohort, could be used to further characterize and differentiate between persistent post-traumatic headache subgroups in studies aimed to improve treatment.
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Affiliation(s)
- Dan Levy
- Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Centre, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Hila Gruener
- Department of Physical Therapy, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Miri Riabinin
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yelena Feingold
- Department of Neurology, Sheba Medical Center, Tel Hashomer, Ramat Gan, Israel
| | - Shaul Schreiber
- Department of Psychiatry, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Chaim G Pick
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ruth Defrin
- Department of Physical Therapy, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
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Melia M, Geissler B, König J, Ottersbach HJ, Umbreit M, Letzel S, Muttray A. Pressure pain thresholds: Subject factors and the meaning of peak pressures. Eur J Pain 2018; 23:167-182. [DOI: 10.1002/ejp.1298] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 07/23/2018] [Accepted: 07/29/2018] [Indexed: 12/21/2022]
Affiliation(s)
- Michael Melia
- Institute of Occupational, Social and Environmental Medicine University Medical Center Johannes Gutenberg University Mainz Germany
| | - Britta Geissler
- Institute of Occupational, Social and Environmental Medicine University Medical Center Johannes Gutenberg University Mainz Germany
| | - Jochem König
- Institute of Medical Biostatistics, Epidemiology and Informatics Division Biostatistics and Bioinformatics University Medical Center Johannes Gutenberg University Mainz Germany
| | - Hans Jürgen Ottersbach
- Institute for Occupational Safety of the German Social Accident Insurance Sankt Augustin Germany
| | - Matthias Umbreit
- BGHM (Expert Committee Woodworking and Metalworking of the German Insurance Association) Mainz Germany
| | - Stefan Letzel
- Institute of Occupational, Social and Environmental Medicine University Medical Center Johannes Gutenberg University Mainz Germany
| | - Axel Muttray
- Institute of Occupational, Social and Environmental Medicine University Medical Center Johannes Gutenberg University Mainz Germany
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Kermavnar T, Power V, de Eyto A, O'Sullivan L. Cuff Pressure Algometry in Patients with Chronic Pain as Guidance for Circumferential Tissue Compression for Wearable Soft Exoskeletons: A Systematic Review. Soft Robot 2018; 5:497-511. [PMID: 29957130 DOI: 10.1089/soro.2017.0088] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
In this article, we report on a systematic review of the literature on pressure-pain thresholds induced and assessed by computerized cuff pressure algometry (CPA). The motivation for this review is to provide design guidance on pressure levels for wearable soft exoskeletons and similar wearable robotics devices. In our review, we focus on CPA studies of patients who are candidates for wearable soft exoskeletons, as pain-related physiological mechanisms reportedly differ significantly between healthy subjects and patients with chronic pain. The results indicate that circumferential limb compression in patients most likely becomes painful at ∼10-18 kPa and can become unbearable even below 25 kPa. The corresponding ranges for healthy control subjects are 20-42 kPa (painful limits) and 34-84 kPa (unbearable levels). In addition, the increase of pain with time tends to be significantly higher, and the adaptation to pain significantly lower, than in healthy subjects. The results of this review provide guidance to designers of wearable robotics for populations with chronic pain regarding rates and magnitudes of tissue compression that may be unacceptable to users.
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Affiliation(s)
- Tjaša Kermavnar
- School of Design and Health Research Institute, University of Limerick , Limerick, Ireland
| | - Valerie Power
- School of Design and Health Research Institute, University of Limerick , Limerick, Ireland
| | - Adam de Eyto
- School of Design and Health Research Institute, University of Limerick , Limerick, Ireland
| | - Leonard O'Sullivan
- School of Design and Health Research Institute, University of Limerick , Limerick, Ireland
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Brill S, Sprecher E, Smith FJD, Geva N, Gruener H, Nahman-Averbuch H, Defrin R. Chronic pain in pachyonychia congenita: evidence for neuropathic origin. Br J Dermatol 2018; 179:154-162. [PMID: 29210461 DOI: 10.1111/bjd.16217] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/28/2017] [Indexed: 12/25/2022]
Abstract
BACKGROUND Pachyonychia congenita (PC) is a rare autosomal dominant skin disease, with chronic pain being the most prominent complaint. Histological studies showing alterations in sensory innervation, along with reports on alterations in mechanical sensitivity, suggest that PC may be a form of neuropathy. OBJECTIVES Here, for the first time, we aim to evaluate systematically the sensory function of patients with PC vs. controls, in order to investigate the pathophysiology of PC. METHODS Patients (n = 62) and controls (n = 45) completed the McGill and Douleur Neuropathique-4 (DN4) questionnaires. Sensory testing included detection and pain thresholds, pathological sensations, conditioned pain modulation (CPM) and temporal summation of pain. RESULTS A moderate-to-severe chronic pain in the feet, throbbing and stabbing in quality, was highly prevalent among patients with PC (86%) and was especially debilitating during weight bearing. In addition, the majority of patients had a DN4 score ≥ 4 (62%), static allodynia (55%) and tingling (53%) in the feet. Compared with controls, patients with PC exhibited thermal and mechanical hypoaesthesia and mechanical hyperalgesia in the feet. CPM was reduced among the patients, and was associated with more enhanced mechanical hyperalgesia in the feet. The specific gene and nature of the causative mutation did not affect any of these features. CONCLUSIONS Although thermal and mechanical hypoaesthesia may result from thicker skin, its presentation in painful regions, along with mechanical hyperalgesia and allodynia, point towards the possibility of neuropathic changes occurring in PC. The clinical features and DN4 scores support this possibility and therefore neuropathic pain medications may be beneficial for patients with PC.
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Affiliation(s)
- S Brill
- Center for Pain Medicine, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel
| | - E Sprecher
- Department of Dermatology, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel.,Department of Dermatology, Tel-Aviv University, Tel-Aviv, 69978, Israel
| | - F J D Smith
- Pachyonychia Congenita Project, School of Life Sciences, University of Dundee, Dundee, U.K
| | - N Geva
- Department of Physical Therapy, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, 69978, Israel.,Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, 69978, Israel
| | - H Gruener
- Department of Physical Therapy, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, 69978, Israel.,Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, 69978, Israel
| | - H Nahman-Averbuch
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, U.S.A
| | - R Defrin
- Department of Physical Therapy, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, 69978, Israel.,Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, 69978, Israel
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Kermavnar T, Power V, de Eyto A, O'Sullivan LW. Computerized Cuff Pressure Algometry as Guidance for Circumferential Tissue Compression for Wearable Soft Robotic Applications: A Systematic Review. Soft Robot 2017; 5:1-16. [PMID: 29412078 DOI: 10.1089/soro.2017.0046] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In this article, we review the literature on quantitative sensory testing of deep somatic pain by means of computerized cuff pressure algometry (CPA) in search of pressure-related safety guidelines for wearable soft exoskeleton and robotics design. Most pressure-related safety thresholds to date are based on interface pressures and skin perfusion, although clinical research suggests the deep somatic tissues to be the most sensitive to excessive loading. With CPA, pain is induced in deeper layers of soft tissue at the limbs. The results indicate that circumferential compression leads to discomfort at ∼16-34 kPa, becomes painful at ∼20-27 kPa, and can become unbearable even below 40 kPa.
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Affiliation(s)
- Tjaša Kermavnar
- School of Design and Health Research Institute, University of Limerick , Limerick, Ireland
| | - Valerie Power
- School of Design and Health Research Institute, University of Limerick , Limerick, Ireland
| | - Adam de Eyto
- School of Design and Health Research Institute, University of Limerick , Limerick, Ireland
| | - Leonard W O'Sullivan
- School of Design and Health Research Institute, University of Limerick , Limerick, Ireland
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Chantelau EA. Conventional deep pressure algometry is not suitable for clinical assessment of nociception in painless diabetic neuropathy. Diabet Foot Ankle 2016; 7:31922. [PMID: 27702429 PMCID: PMC5045473 DOI: 10.3402/dfa.v7.31922] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 08/24/2016] [Accepted: 09/03/2016] [Indexed: 12/29/2022]
Abstract
Background In diabetic persons with painless neuropathic foot ulceration, foot skin was found to be insensate to noxious pinprick stimulation (stimulation area less than 0.05 mm2), while compression of deep subcutaneous foot tissues by Algometer II® (stimulation area 1 cm2) could evoke a deep dull aching. To elucidate this discrepancy, the Algometer II stimulation technique was critically reviewed by varying probe sizes and anatomical sites in the same study population 3 years later. Methods Ten control subjects without neuropathy and 11 persons with painless diabetic neuropathy (PLDN, seven of whom with diabetic foot syndrome, i.e., past painless foot ulcer, or inactive Charcot arthropathy) were re-examined using Algometer II. Deep pressure pain perception threshold (DPPPT) was measured in random sequence with stimulation areas of 0.5 cm2, 1 cm2, and 2 cm2 (separated by 5 min intervals), at the plantar forefoot, the instep, and the hindfoot of both legs. Results In the control and PLDN groups, median DPPPTs differed significantly between stimulation areas (highest with 0.5 cm2, intermediate with 1 cm2, lowest with 2 cm2; p<0.001), and varied moderately by anatomical site. Between-group differences were relatively small. Results of the 1 cm2 assessments repeated 3 years apart were similar. Conclusions Algometer II readings represent spatial summation of low-threshold pressure-receptor rather than of high-threshold nociceptor stimulation and are, thus, unhelpful for assessing PLDN. Reproducibility of the measurements is good.
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15
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Lindskou TA, Christensen SW, Graven-Nielsen T. Cuff Algometry for Estimation of Hyperalgesia and Pain Summation. PAIN MEDICINE 2016; 18:468-476. [DOI: 10.1093/pm/pnw168] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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16
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Slimani H, Plaghki L, Ptito M, Kupers R. Pain hypersensitivity in congenital blindness is associated with faster central processing of C-fibre input. Eur J Pain 2016; 20:1519-29. [DOI: 10.1002/ejp.876] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/28/2016] [Indexed: 11/11/2022]
Affiliation(s)
- H. Slimani
- Chaire de recherche Harland Sanders en Sciences de la vision; École d'Optométrie; Université de Montréal; Canada
- BRAINlab; Department of Neuroscience and Pharmacology; Faculty of Health and Medical Sciences; Panum Institute; University of Copenhagen; Denmark
| | - L. Plaghki
- Unité COSY; Institute of Neuroscience; Université Catholique de Louvain; Brussels Belgium
| | - M. Ptito
- Chaire de recherche Harland Sanders en Sciences de la vision; École d'Optométrie; Université de Montréal; Canada
- BRAINlab; Department of Neuroscience and Pharmacology; Faculty of Health and Medical Sciences; Panum Institute; University of Copenhagen; Denmark
- Laboratory of Neuropsychiatry; Psychiatric Centre Copenhagen; University of Copenhagen; Denmark
| | - R. Kupers
- Chaire de recherche Harland Sanders en Sciences de la vision; École d'Optométrie; Université de Montréal; Canada
- BRAINlab; Department of Neuroscience and Pharmacology; Faculty of Health and Medical Sciences; Panum Institute; University of Copenhagen; Denmark
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17
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Defrin R, Riabinin M, Feingold Y, Schreiber S, Pick CG. Deficient pain modulatory systems in patients with mild traumatic brain and chronic post-traumatic headache: implications for its mechanism. J Neurotrauma 2015; 32:28-37. [PMID: 25068510 DOI: 10.1089/neu.2014.3359] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Although the prevalence rate of chronic post-traumatic headache (CPTHA) after mild traumatic brain injury (TBI) reaches up to 95%, its mechanism is unknown, and little is known about the characteristics of the pain system in this condition. Our aim was to investigate the capabilities of two pain modulatory systems among individuals with CPTHA and study their association with CPTHA, here for the first time. Forty-six subjects participated; 16 with TBI and CPTHA, 12 with TBI without CPTHA, and 18 healthy controls. Testing included the measurement of heat-pain (HPT) and pressure-pain (PPT) thresholds in the forehead and forearm, pain adaptation to tonic noxious heat, and conditioned pain modulation (CPM).The participants completed a post-traumatic stress disorder (PTSD) questionnaire. The two TBI groups did not differ in the TBI and background characteristics. However, TBI patients with CPTHA had significantly higher HPT and lower PPT in the cranium and higher PTSD symptomatology than TBI patients without CPTHA and healthy controls. Adaptation to pain and CPM were diminished in the CPTHA group compared with the two control groups. The intensity of CPTHA correlated negatively with cranial PPT, magnitude of pain adaptation, and CPM. CPTHA intensity correlated positively with PTSD symptomatology. CPTHA appears to be characterized by cranial hyperalgesia and dysfunctional pain modulation capabilities, which are associated with CPTHA magnitude. It is concluded that damage to pain modulatory systems along with chronic cranial sensitization underlies the development of CPTHA. PTSD may reinforce CPTHA and vice versa. Clinical implications are discussed.
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Affiliation(s)
- Ruth Defrin
- 1 Department of Physical Therapy, Sackler Faculty of Medicine, Tel-Aviv University , Tel-Aviv, Israel
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18
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Measuring mechanical pain: the refinement and standardization of pressure pain threshold measurements. Behav Res Methods 2015; 47:216-27. [PMID: 24570335 DOI: 10.3758/s13428-014-0453-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Pain thresholds are widely used in behavioral research, but unlike other pain modalities, a standardized assessment of pressure pain remains a challenge. In this research, we describe the application of an automatic pressure algometer with a linear increase in force. Ergonomically designed fixation devices were developed to increase the accuracy and to shorten the time of each measurement. Ten healthy volunteers were included in a pilot study to test the algometry method. Pressure pain thresholds (PPTs) were investigated over 2 experimental days in three nonconsecutive runs at 29 measurement sites. During the experiment, subjects reported their subjective sleepiness, level of state-anxiety, psychological status and the perceived pain intensity of each measurement. Pain intensity ratings indicate that instructions were followed. State-anxiety and subjective sleepiness levels were low throughout the experiment. The method has proven to be suitable for standardized PPT measurements across the body in an ergonomic, safe, and user-friendly fashion.
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Defrin R, Schreiber S, Ginzburg K. Paradoxical Pain Perception in Posttraumatic Stress Disorder: The Unique Role of Anxiety and Dissociation. THE JOURNAL OF PAIN 2015; 16:961-70. [PMID: 26168878 DOI: 10.1016/j.jpain.2015.06.010] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 06/07/2015] [Accepted: 06/18/2015] [Indexed: 11/16/2022]
Abstract
UNLABELLED Posttraumatic stress disorder (PTSD) and chronic pain often co-occur and exacerbate each other. Elucidating the mechanism of this co-occurrence therefore has clinical importance. Previously, patients with PTSD with chronic pain were found to demonstrate a unique paradoxical pain profile: hyperresponsiveness together with hyposensitivity to pain. Our aim was to examine whether 2 seemingly paradoxical facets of PTSD (anxiety and dissociation) underlie this paradoxical profile. Patients with PTSD (n = 32) and healthy control individuals (n = 43) underwent psychophysical testing and completed questionnaires. Patients with PTSD had higher pain thresholds and higher pain ratings to suprathreshold stimuli than control individuals. Pain thresholds were positively associated with dissociation levels and negatively associated with anxiety sensitivity levels. Experimental pain ratings were positively associated with anxiety sensitivity and negatively related to dissociation levels. Chronic pain intensity was associated with anxiety, anxiety sensitivity, and pain catastrophizing. It appears that reduced conscious attention toward incoming stimuli, resulting from dissociation, causes delayed response in pain threshold measurement, whereas biases toward threatening stimuli and decreased inhibition, possibly caused by increased anxiety, are responsible for the intensification of experimental and chronic pain. The paradoxical facets of PTSD and their particular influences over pain perception seem to reinforce the coexistence of PTSD and chronic pain, and should be considered when treating traumatized individuals. PERSPECTIVE This article provides new information regarding the underlying mechanism of the coexistence of PTSD and chronic pain. This knowledge could help to provide better management of PTSD and chronic pain among individuals in the aftermath of trauma.
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Affiliation(s)
- Ruth Defrin
- Department of Physical Therapy, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel; Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, Israel.
| | - Shaul Schreiber
- Department of Psychiatry, Sourasky Medical Center, Tel-Aviv University, Tel-Aviv, Israel; Department of Psychiatry, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Karni Ginzburg
- Bob Shapell School of Social Work, Tel-Aviv University, Tel-Aviv, Israel
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20
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Chantelau EA. Nociception at the diabetic foot, an uncharted territory. World J Diabetes 2015; 6:391-402. [PMID: 25897350 PMCID: PMC4398896 DOI: 10.4239/wjd.v6.i3.391] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 09/18/2014] [Accepted: 01/20/2015] [Indexed: 02/05/2023] Open
Abstract
The diabetic foot is characterised by painless foot ulceration and/or arthropathy; it is a typical complication of painless diabetic neuropathy. Neuropathy depletes the foot skin of intraepidermal nerve fibre endings of the afferent A-delta and C-fibres, which are mostly nociceptors and excitable by noxious stimuli only. However, some of them are cold or warm receptors whose functions in diabetic neuropathy have frequently been reported. Hence, it is well established by quantitative sensory testing that thermal detection thresholds at the foot skin increase during the course of painless diabetic neuropathy. Pain perception (nociception), by contrast, has rarely been studied. Recent pilot studies of pinprick pain at plantar digital skinfolds showed that the perception threshold was always above the upper limit of measurement of 512 mN (equivalent to 51.2 g) at the diabetic foot. However, deep pressure pain perception threshold at musculus abductor hallucis was beyond 1400 kPa (equivalent to 14 kg; limit of measurement) only in every fifth case. These discrepancies of pain perception between forefoot and hindfoot, and between skin and muscle, demand further study. Measuring nociception at the feet in diabetes opens promising clinical perspectives. A critical nociception threshold may be quantified (probably corresponding to a critical number of intraepidermal nerve fibre endings), beyond which the individual risk of a diabetic foot rises appreciably. Staging of diabetic neuropathy according to nociception thresholds at the feet is highly desirable as guidance to an individualised injury prevention strategy.
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21
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Defrin R, Arad M, Ben-Sasson M, Ginzburg K. Attitudes and emotions towards pain and sensitivity to painful stimuli among people routinely engaging in masochistic behaviour. Eur J Pain 2015; 19:1321-30. [DOI: 10.1002/ejp.662] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/28/2014] [Indexed: 11/07/2022]
Affiliation(s)
- R. Defrin
- Department of Physical Therapy; School of Allied Health Professions; Sackler Faculty of Medicine; Tel-Aviv University; Israel
- Sagol School of Neurosciences; Tel-Aviv University; Israel
| | - M. Arad
- Department of Physical Therapy; School of Allied Health Professions; Sackler Faculty of Medicine; Tel-Aviv University; Israel
| | - M.P. Ben-Sasson
- Department of Physical Therapy; School of Allied Health Professions; Sackler Faculty of Medicine; Tel-Aviv University; Israel
| | - K. Ginzburg
- Bob Shapell School of Social work; Tel-Aviv University; Israel
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22
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Spatial Summation of Pain in Humans Investigated Using Transcutaneous Electrical Stimulation. THE JOURNAL OF PAIN 2015; 16:11-8. [DOI: 10.1016/j.jpain.2014.10.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 09/24/2014] [Accepted: 10/08/2014] [Indexed: 01/02/2023]
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Duan G, Xiang G, Zhang X, Guo S, Zhang Y. An improvement of mechanical pain sensitivity measurement method: the smaller sized probes may detect heterogeneous sensory threshold in healthy male subjects. PAIN MEDICINE 2013; 15:272-80. [PMID: 24118900 DOI: 10.1111/pme.12245] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECTIVE On the basis of our experience in the application of the mechanical algometer and a number of pilot experiments, we speculated that 0.1- and 0.01-cm(2) probes might improve the measurement of mechanical pain sensitivity relative to the conventional 1-cm(2) probe. Here, we examined the accuracy, feasibility, and applicability of these probes in detecting the mechanical pain sensitivity. DESIGN Mechanical pain threshold and tolerance tests were performed on subjects using the three probes of 1, 0.1, and 0.01 cm(2) in random order. We compared the application of these probes. SETTING The study was set at the Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. SUBJECTS Fifty healthy male Han Chinese subjects were recruited. OUTCOME MEASURES We compared the qualities of stimulus-evoked pain, test stability, the measuring time, the subjects' acceptance level of the procedure, the validity of pain measurement, and the arduousness of the task for the investigator among the three different size probes. RESULTS Compared with the conventional 1-cm(2) probe, the 0.01- and 0.1-cm(2) probes resulted in the subjects responding to stimulus-evoked pain more quickly, accurately, and consistently, and also made the measurement more comfortable for investigators. Up to 80% of the subjects reported the pain quality as a pricking sensation when the 0.01-cm(2) probe was used. CONCLUSION The use of the 0.1-cm(2) probe might be more suitable as an optimized method for the detection of pressure pain sensitivity in clinical studies. In addition, the 0.01-cm(2) probe could potentially serve as an alternative to the weighted needle pinprick, providing continuous quantizing detection for pricking pain sensitivity.
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Affiliation(s)
- Guangyou Duan
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Rodrigo AS, Goonetilleke RS, Xiong S. Load distribution to minimise pressure-related pain on foot: a model. ERGONOMICS 2013; 56:1180-1193. [PMID: 23697812 DOI: 10.1080/00140139.2013.797111] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
UNLABELLED The optimal force distribution to minimise pain or discomfort at the foot-shoe interface is still not known. Most shoe-related products attempt to distribute the load uniformly without much consideration to the bony and soft tissue regions. An experiment was conducted to first determine the pressure pain threshold (PPT) and tissue deformation on the plantar surface of the foot. Circular probes of areas 0.5, 1.0 and 2.0 cm(2) at indentation speeds of 0.5, 1 and 2 mm/s showed that PPT depends on the location stimulated, area of stimulation and the indentation speed. The results also showed that tissue stiffness is quite low for small deformations ( < 4 mm), but significantly higher at large deformations (>4 mm). The stiffness at the larger deformation region was positively correlated with PPT (r = 0.63, p < 0.001). The data were further used to develop a model with PPT, deformation and stimulated area. PRACTITIONER SUMMARY Pressure at which there is an onset of pain is higher when a larger area of soft tissue is stimulated. Bony areas may be better suited to bear load on smaller areas to minimise pressure-related pain. Thus, manipulating supporting surface stiffness and surface contours can help minimise pain.
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Affiliation(s)
- Asanka S Rodrigo
- Department of Electrical Engineering, University of Moratuwa, Katubedda, Sri Lanka
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25
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Xiong S, Goonetilleke RS, Rodrigo WDAS, Zhao J. A model for the perception of surface pressure on human foot. APPLIED ERGONOMICS 2013; 44:1-10. [PMID: 22835623 DOI: 10.1016/j.apergo.2012.04.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Revised: 02/27/2012] [Accepted: 04/04/2012] [Indexed: 06/01/2023]
Abstract
The psychophysical relationship between the magnitude of pressure on thirteen test locations of twenty healthy subjects' feet with four probe areas at three indentation speeds and the corresponding perceived sensations were analyzed. The dependency of pressure pain thresholds (PPT) on area, A, and speed, v, can be mathematically modeled in the form, PPT(i) = [a(i) + bLn(v)]A(β)i = 1,2…13 where β and b are constants and are dependent on location and gender, and a(i) is a constant highly correlated with foot tissue stiffness. The relationship between the sensory intensity to pressure magnitude appears to follow a modified Stevens' power law with power exponents less than 1.0 and consistent across the 13 test locations with a mean of 0.82 and a range from 0.67 to 0.98. This particular model helps to understand the sensation of pressure threshold and its impact in the design of consumer products.
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Affiliation(s)
- Shuping Xiong
- School of Design and Human Engineering, Ulsan National Institute of Science and Technology, Ulsan Metropolitan City 689-798, South Korea
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26
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Finocchietti S, Nielsen M, Mørch CD, Arendt-Nielsen L, Graven-Nielsen T. Pressure-induced muscle pain and tissue biomechanics: A computational and experimental study. Eur J Pain 2012; 15:36-44. [DOI: 10.1016/j.ejpain.2010.05.010] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2010] [Revised: 04/28/2010] [Accepted: 05/20/2010] [Indexed: 11/16/2022]
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27
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Interactions between spatial summation, 2-point discrimination and habituation of heat pain. Eur J Pain 2012; 12:900-9. [DOI: 10.1016/j.ejpain.2007.12.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2007] [Revised: 12/13/2007] [Accepted: 12/28/2007] [Indexed: 11/20/2022]
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28
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Xiong S, Goonetilleke RS, Jiang Z. Pressure thresholds of the human foot: measurement reliability and effects of stimulus characteristics. ERGONOMICS 2011; 54:282-293. [PMID: 21390958 DOI: 10.1080/00140139.2011.552736] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Information related to reliable values of discomfort thresholds can help to improve the designs of various products. This study aimed to investigate the measurement reliabilities associated with pressure thresholds, while determining the effects of stimulus characteristics (stimulus area, indentation speed) of the human foot. An indentation apparatus was used with four sizes of indentation probes and three indentation speeds. In total, 13 locations on the right foot of 10 male and 10 female participants were tested to determine the pressure discomfort thresholds (PDT) and pressure pain thresholds (PPT). Results show that the tests had very good measurement reliability with intra-class correlations (ICC) greater than 0.8 for the PPT measurements and acceptable reliability (most ICC > 0.75, with a few between 0.5 and 0.75) for the PDT measurements, demonstrating that participants are capable of judging their pain and discomfort thresholds. Pressure sensitivity differs across locations of the foot, with the medial plantar arch of the foot being the most sensitive, followed by the dorsal surface of the foot. The heel area was the least sensitive. PPT and PDT are dependent on the stimulus characteristics of the area and the speed of indentation. A smaller area has a higher PPT and PDT, indicating significant effects of spatial summation. The increase of PDT and PPT at higher speeds may be partially explained by the increase in stiffness because foot tissue exhibits viscoelastic properties. The findings can have a significant impact on the design of footwear and other accessories for improved foot health and comfort. Statement of Relevance: This study investigated the threshold measurement reliability while determining the pressure sensitivity on the surface of the foot with varying stimulus characteristics. The findings may be very useful in the design of footwear and other accessories for improved comfort and reduced injuries.
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Affiliation(s)
- Shuping Xiong
- Department of Industrial Engineering and Management, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, Peoples Republic of China
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29
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Fernández-de-las-Peñas C, Madeleine P, Martínez-Perez A, Arendt-Nielsen L, Jiménez-García R, Pareja JA. Pressure pain sensitivity topographical maps reveal bilateral hyperalgesia of the hands in patients with unilateral carpal tunnel syndrome. Arthritis Care Res (Hoboken) 2010; 62:1055-64. [DOI: 10.1002/acr.20189] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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30
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Zhu YJ, Lu TJ. A multi-scale view of skin thermal pain: from nociception to pain sensation. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2010; 368:521-559. [PMID: 20047938 DOI: 10.1098/rsta.2009.0234] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
All biological bodies live in a thermal environment, including the human body, where skin is the interface with a protecting function. When the temperature is out of the normal physiological range, skin fails to protect, and the pain sensation is evoked. Furthermore, in medicine, with advances in laser, microwave and similar technologies, various thermal therapeutic methods have been widely used to cure disease/injury involving skin tissue. However, the corresponding problem of pain relief has limited further application and development of these thermal treatments. Skin thermal pain is induced through both direct (i.e. an increase/decrease in temperature) and indirect (e.g. thermomechanical and thermochemical) ways, and is governed by complicated thermomechanical-chemical-neurophysiological responses. However, a complete understanding of the underlying mechanisms is still far from clear. In this article, starting from an engineering perspective, we aim to recast the biological behaviour of skin in engineering system parlance. Then, by coupling the concepts of engineering with established methods in neuroscience, we attempt to establish multi-scale modelling of skin thermal pain through ion channel to pain sensation. The model takes into account skin morphological plausibility, the thermomechanical response of skin tissue and the biophysical and neurological mechanisms of pain sensation.
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Affiliation(s)
- Y J Zhu
- Stomatological Hospital, College of Medicine, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
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Srbely JZ, Dickey JP, Bent LR, Lee D, Lowerison M. Capsaicin-induced central sensitization evokes segmental increases in trigger point sensitivity in humans. THE JOURNAL OF PAIN 2009; 11:636-43. [PMID: 20015704 DOI: 10.1016/j.jpain.2009.10.005] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Revised: 09/22/2009] [Accepted: 10/02/2009] [Indexed: 12/19/2022]
Abstract
UNLABELLED This study investigated whether inducing central sensitization evokes segmental increases in trigger point pressure sensitivity. We evoked central sensitization at the C(5) segment and validated its presence via mechanical cutaneous sensitivity (brush allodynia) testing. Trigger point pressure sensitivity was quantified using the pain pressure threshold (PPT) value. A 50 cm(2) area of the C(5) dermatome at the right lateral elbow was pretreated with 45 degrees heat for 10 minutes. Test subjects (n = 20) then received topical capsaicin cream (0.075%; Medicis, Toronto, Canada) to the C(5) dermatome, whereas control subjects (n = 20) received a topical placebo cream (Biotherm Massage, Montreal, Canada). PPT readings were recorded from the infraspinatus (C(5,6)) and gluteus medius (L(4,5)S(1)) trigger points at zero (pre-intervention), 10, 20, and 30 minutes after intervention; all PPT readings were normalized to pre-intervention (baseline) values. The difference between the PPT readings at the 2 trigger point sites represents the direct influence of segmental mechanisms on the trigger point sensitivity at the infraspinatus site (PPT(seg)). Test subjects demonstrated statistically significant increases in Total Allodynia scores and significant decreases in PPT(seg) at 10, 20, and 30 minutes after application, when compared with control subjects. These results demonstrate that increases in central sensitization evoke increases in trigger point pressure sensitivity in segmentally related muscles. PERSPECTIVE Myofascial pain is the most common form of musculoskeletal pain. Myofascial trigger points play an important role in the clinical manifestation of myofascial pain syndrome. Elucidating the role of central sensitization in the pathophysiology of trigger points is fundamental to developing optimal strategies in the management of myofascial pain syndrome.
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Affiliation(s)
- John Z Srbely
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.
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Quevedo AS, Coghill RC. Filling-in, spatial summation, and radiation of pain: evidence for a neural population code in the nociceptive system. J Neurophysiol 2009; 102:3544-53. [PMID: 19759320 DOI: 10.1152/jn.91350.2008] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The receptive field organization of nociceptive neurons suggests that noxious information may be encoded by population-based mechanisms. Electrophysiological evidence of population coding mechanisms has remained limited. However, psychophysical studies examining interactions between multiple noxious stimuli can provide indirect evidence that neuron population recruitment can contribute to both spatial and intensity-related percepts of pain. In the present study, pairs of thermal stimuli (35 degrees C/49 degrees C or 49 degrees C/49 degrees C) were delivered at different distances on the leg (0, 5, 10, 20, 40 cm) and abdomen (within and across dermatomes) and subjects evaluated pain intensity and perceived spatial attributes of stimuli. Reports of perceived pain spreading to involve areas that were not stimulated (radiation of pain) were most frequent at 5- and 10-cm distances (chi(2) = 34.107, P < 0.0001). Perceived connectivity between two noxious stimuli (filling-in) was influenced by the distance between stimuli (chi(2) = 16.756, P < 0.01), with the greatest connectivity reported at 5- and 10-cm separation distances. Spatial summation of pain occurred over probe separation distances as large as 40 cm and six dermatomes (P < 0.05), but was maximal at 5- and 10-cm separation distances. Taken together, all three of these phenomena suggest that interactions between recruited populations of neurons may support both spatial and intensity-related dimensions of the pain experience.
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Affiliation(s)
- Alexandre S Quevedo
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1010, USA
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The influence of age and physical activity on the pressure sensitivity of soft tissues of the musculoskeletal system. J Bodyw Mov Ther 2009; 14:382-90. [PMID: 20850046 DOI: 10.1016/j.jbmt.2009.07.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Revised: 07/02/2009] [Accepted: 07/06/2009] [Indexed: 10/20/2022]
Abstract
SUMMARY BACKGROUND The pressure sensitivity of soft tissues is defined as the slightest pressure causing pain. Sex, movement system illnesses, pain ailments may influence the pressure sensitivity. However, there have been few studies on factors determining the level of pressure sensitivity of skeletal muscles. OBJECTIVE The authors have determined to study the influence of age and physical activity on the pressure sensitivity of skeletal muscles. METHODS The examination of pressure sensitivity of trigger points and muscle insertions was carried out using algometry. RESULTS 76 volunteers (38 students and 38 individuals aged 50-75) participated in the study. The differences in pressure sensitivity between students and people aged 50-75 were not statistically significant. Pressure sensitivity of students differed depending on their level of physical activity. CONCLUSIONS The level of physical activity influenced the pressure sensitivity of skeletal muscles. Age did not significantly influence pressure sensitivity.
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García-Fernández E, Godoy-Izquierdo D, Pérez-García M, Jiménez-Alonso J, López-Chicheri I, Godoy JF. Differences in Pressure-Pain Threshold Between Healthy Women and Patients with Fibromyalgia Syndrome, Systemic Lupus Erythematosus, and Rheumatoid Arthritis. ACTA ACUST UNITED AC 2009. [DOI: 10.1080/10582450902820556] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Nie H, Graven-Nielsen T, Arendt-Nielsen L. Spatial and temporal summation of pain evoked by mechanical pressure stimulation. Eur J Pain 2008; 13:592-9. [PMID: 18926745 DOI: 10.1016/j.ejpain.2008.07.013] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2007] [Revised: 05/14/2008] [Accepted: 07/27/2008] [Indexed: 12/22/2022]
Abstract
Chronic pain patients often suffer from widespread and long lasting pain. The integrative effect of combined spatial and temporal summation on pain intensity has not been quantitatively tested. The present study was designed to investigate: (1) if the size of the stimulation area would facilitate the temporal summation of pain to repetitive pressure stimulation, and (2) if temporal summation is effective when stimulating separated sites, repetitively. Twenty healthy male subjects participated in this study. The test sites were located on the bilateral upper trapezius and tibialis anterior muscles. The ten stimuli (each with a duration of 1s) were applied to a single site at three inter-stimulus intervals (ISI: 1, 5, 30s) using five different probe sizes (0.5, 1, 2, 4 and 8cm(2)). The stimulation intensity was equal to the pressure pain threshold (PPT) determined for each probe size. Similar repetitive stimulations at two inter-stimulus intervals (5s and 30s) using two sizes of probes (0.5cm(2) and 2cm(2)) were applied to ten separate sites. The PPT at the trapezius muscle decreased significantly with the increase in stimulus area from 0.5cm(2) to 8cm(2) (P<0.001) due to spatial summation. Temporal summation of pain was evoked by repetitive pressure stimuli on the same site for all ISI and was more pronounced at 5s and 30s ISI with larger probe areas (2, 4, and 8cm(2)) compared to smaller probe areas. There was no temporal summation of pain to stimuli with ISI 5 and 30s when stimulating the separated sites. The current study indicated that spatial summation facilitated the temporal summation of pain for stimuli given at 5s and 30s ISI. The combination of temporal and spatial integration of nociceptive input facilitates the pain intensity, suggesting that temporal summation is clinically relevant in conditions with widespread pain.
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Affiliation(s)
- HongLing Nie
- Laboratory for Experimental Pain Research, Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
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36
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Summation model of pelvic pain in interstitial cystitis. ACTA ACUST UNITED AC 2008; 5:494-500. [DOI: 10.1038/ncpuro1203] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2008] [Accepted: 07/08/2008] [Indexed: 11/08/2022]
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Srbely JZ, Dickey JP, Lowerison M, Edwards MA, Nolet PS, Wong LL. Stimulation of myofascial trigger points with ultrasound induces segmental antinociceptive effects: a randomized controlled study. Pain 2008; 139:260-266. [PMID: 18508198 DOI: 10.1016/j.pain.2008.04.009] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2006] [Revised: 03/28/2008] [Accepted: 04/15/2008] [Indexed: 10/22/2022]
Abstract
Musculoskeletal pain affects a significant proportion of the general population. The myofascial trigger point is recognized as a key factor in the pathophysiology of musculoskeletal pain. Ultrasound is commonly employed in the treatment and management of soft tissue pain and, in this study, we set out to investigate the segmental antinociceptive effect of ultrasound. Subjects (n=50) with identifiable myofascial trigger points in the supraspinatus, infraspinatus and gluteus medius muscles were selected from an outpatient rehabilitation clinic and randomly assigned to test or control groups. Test subjects received a therapeutic dose of ultrasound to the right supraspinatus trigger point while control groups received a sham (null) exposure. Baseline pain pressure threshold (PPT) readings were recorded at the ipsilateral infraspinatus and gluteus medius trigger-point sites prior to ultrasound exposure. The infraspinatus point was chosen due to its segmental neurologic link with the supraspinatus point; the gluteus medius acted as a segmental control point. Following the ultrasound intervention, PPT readings were recorded at 1, 3, 5, 10 and 15 min intervals at both infraspinatus and gluteus medius trigger points; the difference between infraspinatus and gluteus medius PPT values, PPT seg, represents the segmental influence on the PPT. The ultrasound test group demonstrated statistically significant increases in PPT seg (decreased infraspinatus sensitivity) at 1, 3 and 5 min, when compared with PPT seg in the sham ultrasound group. These results establish that low-dose ultrasound evokes short-term segmental antinociceptive effects on trigger points which may have applications in the management of musculoskeletal pain.
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Affiliation(s)
- John Z Srbely
- Human Health and Nutritional Sciences, University of Guelph, Guelph, Ont., Canada N1G 2W1 Centre for the Genetic Improvement of Livestock, University of Guelph, Guelph, Ont., Canada N1G 2W1 Academic Services, University of Guelph, Guelph, Ont., Canada N1G 2W1 Church Lane Rehabilitation Clinic, Guelph, Ont., Canada N1H 2W6 Biomedical Sciences, University of Guelph, Guelph, Ont., Canada N1G 2W1
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Yarnitsky D. What do pressure pipes tell us about spatial summation in pain processing. Pain 2007; 130:4-5. [PMID: 17499439 DOI: 10.1016/j.pain.2007.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2007] [Accepted: 04/02/2007] [Indexed: 11/28/2022]
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Jones DH, Kilgour RD, Comtois AS. Test-retest reliability of pressure pain threshold measurements of the upper limb and torso in young healthy women. THE JOURNAL OF PAIN 2007; 8:650-6. [PMID: 17553750 DOI: 10.1016/j.jpain.2007.04.003] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2006] [Revised: 03/14/2007] [Accepted: 04/10/2007] [Indexed: 02/07/2023]
Abstract
UNLABELLED The goal of this study was to determine the intra- and interday reliability of pressure pain thresholds (PPT) in the upper extremity and torso of asymptomatic women. Nineteen healthy women (20-39 years) with no underlying musculoskeletal problems had 3 PPT trials performed on 8 different locations in the upper extremity and torso over 4 consecutive days. The test-retest reliability of PPT values was robust and highly consistent over the 4 days. The PPT intraclass correlations (ICC) were highly consistent and repeatable over the 4 days of testing (day 1: ICC = 0.94; day 2: ICC = 0.96; day 3: ICC = 0.97 and day 4: ICC = 0.96). When compared with baseline measurements obtained on day 1, the PPT values were significantly lower (P < .05) on days 2, 3, and 4 at all 8 locations. Although the PPT test-retest reliability is robust and consistent throughout the 4 days, there appears to be a similar overall decline in the magnitude of the absolute PPT response at each of the 8 locations. A specific explanation for this greater overall sensitivity in PPTs at all 8 locations is lacking; however, a centrally mediated alteration in pressure/pain sensation could contribute to the overall trend observed in this study. PERSPECTIVE PPT measurements of the upper limb and torso will be significantly lower with repeated measures over a short period time. A standardized evaluation grid should be included in baseline so as to accurately evaluate the progression in shoulder rehabilitation in women with shoulder dysfunction.
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Affiliation(s)
- David H Jones
- Department of Exercise Science, Concordia University, Montreal, QC, Canada
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40
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Staud R, Koo E, Robinson ME, Price DD. Spatial summation of mechanically evoked muscle pain and painful aftersensations in normal subjects and fibromyalgia patients. Pain 2007; 130:177-87. [PMID: 17459587 PMCID: PMC2041939 DOI: 10.1016/j.pain.2007.03.015] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2006] [Revised: 02/22/2007] [Accepted: 03/12/2007] [Indexed: 10/23/2022]
Abstract
Impulse frequency and number of recruited central neurons are relevant for pain encoding and temporal as well as spatial summation of pain (SSP). Whereas SSP of heat-induced pain is well characterized, mechanical SSP (MSSP) has been less studied. MSSP may be relevant for chronic pain conditions like fibromyalgia (FM) and play an important role in the pathogenesis of this chronic pain syndrome. Our study was designed to determine MSSP in 12 normal controls (NC) and 11 FM subjects. MSSP testing consisted of 5 s suprathreshold pressure-pain stimulations of forearm muscles by up to three identical probes (separated by 4 or 8 cm). The stimulated areas ranged between 0.79 and 2.37 cm2. The subjects rated the pain intensity of mechanical stimuli as well as pain aftersensations. Although MSSP increased monotonically in NC and FM subjects, pressure pain and pressure pain aftersensations were greater in FM subjects and highly associated with clinical pain intensity (r2=.44-.64), suggesting that spatial and temporal summation factors may contribute to overall clinical pain. However, despite higher experimental pain ratings, the magnitude of MSSP was not statistically different between NC and FM subjects. Furthermore, muscle stimuli elicited more MSSP when separated by 8 cm than 4 cm and this finding was not different between NC and FM subjects. Thus, mechanisms of MSSP were similar for both FM and NC subjects. The important role of MSSP for pain encoding suggests that decreasing pain in some muscle areas by local anesthetics or other means may improve overall clinical pain of FM patients.
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Affiliation(s)
- Roland Staud
- Department of Medicine, University of Florida, College of Medicine, Gainesville, FL 32610-0221, USA.
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41
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Quevedo AS, Coghill RC. An Illusion of Proximal Radiation of Pain Due to Distally Directed Inhibition. THE JOURNAL OF PAIN 2007; 8:280-6. [PMID: 17145203 DOI: 10.1016/j.jpain.2006.09.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2006] [Revised: 08/23/2006] [Accepted: 09/02/2006] [Indexed: 11/30/2022]
Abstract
UNLABELLED The perceived site of pain can frequently radiate from the site of tissue injury. However, the mechanisms supporting spatial aspects of cutaneous pain radiation remain poorly understood. Such mismatches between the actual location and the perceived location of stimuli are also found across other somatosensory modalities. During simultaneous innocuous stimulation at multiple sites, proximal stimuli are perceived as more intense than distal stimuli. To determine if pain radiates in a predominantly proximal direction, 20 subjects rated pain intensity from simultaneously applied pairs of noxious (49 degrees C) thermal stimuli. Proximal and distal stimuli were each rated separately. As the distance between probes was decreased, pain from the proximal site increased relative to that arising from the distal site. Comparisons between paired stimuli and single control (49 degrees C) stimuli revealed that pain arising from the distal stimulus site was inhibited. This distally directed inhibition produced an illusion that pain radiates in a proximal direction. The proximal radiation/distal inhibition of pain observed in the present investigation may represent a perceptual "copy" of neural information used to modulate withdrawal responses. Thus, supraspinally mediated responses to pain can be coordinated with spinally mediated withdrawal reflexes. PERSPECTIVE Radiation of pain is a perplexing clinical problem. The present findings indicate that the perceived location of pain may be shaped by inhibitory as well as facilitatory processes.
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Affiliation(s)
- Alexandre S Quevedo
- Department of Neurobiology and Anatomy, Center for the Study of Pharmacologic Plasticity in the Presence of Pain, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1010, USA
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Defrin R, Givon R, Raz N, Urca G. Spatial summation and spatial discrimination of pain sensation. Pain 2006; 126:123-31. [PMID: 16860477 DOI: 10.1016/j.pain.2006.06.026] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2006] [Revised: 04/09/2006] [Accepted: 06/19/2006] [Indexed: 11/30/2022]
Abstract
The aims of this study were to explore: (a) the interrelation between spatial summation (SS) and spatial discrimination (SD) of pain, (b) whether the two phenomena are subserved by different sensory channels. SS and SD of pain were measured with contact heat stimuli delivered at slow (0.50 degrees C/s) and fast (40 degrees C/s) rise times. Pressure nerve block of the radial nerve was employed to assess whether differential activation of C and A delta fibers is obtained by these different rates of rise. Two discrete stimuli (each 3x3 cm) were applied to the forearm with separation distances between them varying from 0 to 30 cm. A single stimulus or two applied simultaneously were employed. For each distance heat-pain threshold (HPT) and suprathreshold pain ratings were obtained and subjects were asked to report the number of pain spots perceived (SD). SS of HPT occurred at separations smaller than 10 cm whereas significant SD occurred only from a separation of 10 cm and up. SS of suprathreshold sensations was completely accounted for by threshold changes. Stimulation rate did not affect SS or SD. Following nerve block, thresholds obtained with the fast rise stimulation increased significantly (HPT rose from 46.2 to 50.5 degrees C) but those obtained with slow rise stimuli were not affected by the block, indicating that C and A delta fibers were activated selectively. The results suggest that: (a) SS and SD are mutually exclusive functions of the nociceptive systems, (b) C and A delta nociceptors are probably similarly involved in these functions.
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Affiliation(s)
- Ruth Defrin
- Department of Physical Therapy, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
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43
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Lautenbacher S, Kunz M, Strate P, Nielsen J, Arendt-Nielsen L. Age effects on pain thresholds, temporal summation and spatial summation of heat and pressure pain. Pain 2005; 115:410-418. [PMID: 15876494 DOI: 10.1016/j.pain.2005.03.025] [Citation(s) in RCA: 272] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2004] [Revised: 03/10/2005] [Accepted: 03/21/2005] [Indexed: 12/20/2022]
Abstract
Experimental data on age-related changes in pain perception have so far been contradictory. It has appeared that the type of pain induction method is critical in this context, with sensitivity to heat pain being decreased whereas sensitivity to pressure pain may be even enhanced in the elderly. Furthermore, it has been shown that temporal summation of heat pain is more pronounced in the elderly but it has remained unclear whether age differences in temporal summation are also evident when using other pain induction methods. No studies on age-related changes in spatial summation of pain have so far been conducted. The aim of the present study was to provide a comprehensive survey on age-related changes in pain perception, i.e. in somatosensory thresholds (warmth, cold, vibration), pain thresholds (heat, pressure) and spatial and temporal summation of heat and pressure pain. We investigated 20 young (mean age 27.1 years) and 20 elderly (mean age 71.6 years) subjects. Our results confirmed and extended previous findings by showing that somatosensory thresholds for non-noxious stimuli increase with age whereas pressure pain thresholds decrease and heat pain thresholds show no age-related changes. Apart from an enhanced temporal summation of heat pain, pain summation was not found to be critically affected by age. The results of the present study provide evidence for stimulus-specific changes in pain perception in the elderly, with deep tissue (muscle) nociception being affected differently by age than superficial tissue (skin) nociception. Summation mechanisms contribute only moderately to age changes in pain perception.
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Affiliation(s)
- Stefan Lautenbacher
- Physiological Psychology, Otto-Friedrich University Bamberg, Markuspl. 3, D-96045 Bamberg, Germany Department of Psychiatry and Psychotherapy, Philipps University Marburg, Germany Center for Sensory-Motor Interaction, Aalborg University, Denmark
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44
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Rolke R, Andrews Campbell K, Magerl W, Treede RD. Deep pain thresholds in the distal limbs of healthy human subjects. Eur J Pain 2005; 9:39-48. [PMID: 15629873 DOI: 10.1016/j.ejpain.2004.04.001] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2003] [Revised: 04/10/2004] [Indexed: 02/07/2023]
Abstract
Pressure pain thresholds (PPTs) in distal limbs have been under-investigated despite their potential clinical importance. Therefore, we compared PPTs over nail bed, bony prominences, and muscle in distal parts of upper and lower limbs. We investigated 12 healthy subjects using three handheld devices: a spring-loaded, analogue pressure threshold meter (PTM) with two operating ranges, and an electronic Algometer. PPTs were determined with three series of ascending stimulus intensities with a ramp of about 50 kPa/s. PPTs were normally distributed in logarithmic space. PPTs over different tissues varied significantly (ANOVA, p<0.001): mean thresholds and 95% confidence intervals were 615 kPa (266-1424 kPa) over the nail bed, 581 kPa (271-1245 kPa) over bony prominences, and 520 kPa (246-1100 kPa) over muscles. PPTs on the foot were higher than on the hand (ANOVA, p<0.01), except over muscles. PPTs were significantly lower with the Algometer than with PTMs (ANOVA, p<0.01); again these differences were least when testing over muscle. There was no significant right-left difference (ANOVA, p=0.33). In spite of considerable variability across subjects, reproducibility within subjects was high (correlation coefficients>0.90). For within-subject comparisons, threshold elevations beyond 33-43% would be abnormal (95% confidence intervals), whereas only deviations from the group mean by at least a factor of two would be abnormal with respect to absolute normative values. PPTs over distal muscles were comparable to published values on proximal limb and trunk muscles. These findings suggest that pressure pain testing over distal muscles may be a sensitive test for deep pain sensitivity and that the simple and less expensive devices are sufficient for testing this tissue type. Intra-individual site-to-site comparisons will be more sensitive than absolute normative values.
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Affiliation(s)
- R Rolke
- Institute of Physiology and Pathophysiology, Johannes Gutenberg University, Saarstr. 21, D-55099 Mainz, Germany
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45
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Staud R, Vierck CJ, Robinson ME, Price DD. Spatial summation of heat pain within and across dermatomes in fibromyalgia patients and pain-free subjects. Pain 2004; 111:342-350. [PMID: 15363878 DOI: 10.1016/j.pain.2004.07.015] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2004] [Revised: 06/22/2004] [Accepted: 07/14/2004] [Indexed: 11/15/2022]
Abstract
The mechanisms of spatial summation of pain (SSP) include pain coding dependent on impulse frequency and the number of recruited central neurons. However, SSP may also be influenced by pain inhibitory mechanisms, such as diffuse noxious inhibitory controls. Abnormal interactions between pain inhibitory mechanisms and SSP may be relevant for chronic pain conditions such as fibromyalgia (FM) and may help explain why widespread pain is characteristic for this chronic pain syndrome. The present study was designed to determine the difference of thermal SSP in the upper extremities between FM and normal control (NC) subjects, particularly within and across dermatomes of the hand. Fourteen NC and 19 FM subjects were enrolled in this study. SSP testing sessions involved immersion of each individual fingertip as well as stepwise immersion of the fingers, hands, and forearms in a hot water bath (46 degrees Celsius) for 5s and 20s. In addition, immersion of several fingertips across dermatome C(7)-C(8) was compared to progressive immersion of the index finger (dermatome C(7)). These experiments demonstrated significant spatial summation of heat-induced pain in both FM and NC subjects. SSP was most extensive within the fingers, and became negligible as the stimulus area increased above the hand. Furthermore, SSP was more pronounced within one dermatome such as that of the index finger than across several dermatomes of the hand. These results were similar for both FM and NC subjects. Thus, mechanisms of SSP, including possible inhibitory factors that limit this relevant pain mechanism, appear to be similar for both FM and NC subjects.
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Affiliation(s)
- Roland Staud
- Department of Medicine, McKnight Brain Institute, University of Florida, College of Medicine, 1600 SW Archer Road, P.O. Box 100221, Gainesville, FL 32610-0221, USA Department of Neuroscience, McKnight Brain Institute, University of Florida, College of Medicine, 1600 SW Archer Road, P.O. Box 100221, Gainesville, FL 32610-0221, USA Department of Clinical and Health Psychology, McKnight Brain Institute, University of Florida, College of Medicine, 1600 SW Archer Road, P.O. Box 100221, Gainesville, FL 32610-0221, USA Department of Oral Surgery, McKnight Brain Institute, University of Florida, College of Medicine, 1600 SW Archer Road, P.O. Box 100221, Gainesville, FL 32610-0221, USA
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