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Karmakar S, Kesh A, Muniyandi M. Thermal illusions for thermal displays: a review. Front Hum Neurosci 2023; 17:1278894. [PMID: 38116235 PMCID: PMC10728301 DOI: 10.3389/fnhum.2023.1278894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 11/16/2023] [Indexed: 12/21/2023] Open
Abstract
Thermal illusions, a subset of haptic illusions, have historically faced technical challenges and limited exploration. They have been underutilized in prior studies related to thermal displays. This review paper primarily aims to comprehensively categorize thermal illusions, offering insights for diverse applications in thermal display design. Recent advancements in the field have spurred a fresh perspective on thermal and pain perception, specifically through the lens of thermal illusions.
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Affiliation(s)
- Subhankar Karmakar
- Department of Applied Mechanics and Biomedical Engineering, Indian Institute of Technology Madras, Chennai, India
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Adam F, Jouët P, Sabaté JM, Perrot S, Franchisseur C, Attal N, Bouhassira D. Thermal grill illusion of pain in patients with chronic pain: a clinical marker of central sensitization? Pain 2023; 164:638-644. [PMID: 35972466 DOI: 10.1097/j.pain.0000000000002749] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 07/14/2022] [Indexed: 11/25/2022]
Abstract
ABSTRACT The thermal grill illusion of pain (TGIP) is a paradoxical burning pain sensation elicited by the simultaneous application of innocuous cutaneous warm and cold stimuli with a thermode ("thermal grill") consisting of interlaced heated and cooled bars. Its neurophysiological mechanisms are unclear, but TGIP may have some mechanisms in common with pathological pain, including central sensitization in particular, through the involvement of N-methyl- d -aspartate receptors. However, few studies have investigated TGIP in patients with chronic pain and its clinical relevance is uncertain. We hypothesized that the TGIP would be increased in comparison with controls in patients with fibromyalgia or irritable bowel syndrome, which are regarded as typical "nociplastic" primary pain syndromes related to changes in central pain processing. We compared the sensations elicited by a large range of combinations of temperature differentials between the warm and cold bars of a thermal grill applied to the hand between patients with fibromyalgia (n = 30) or irritable bowel syndrome (n= 30) and controls (n = 30). The percentage of TGIP responses and the intensity and unpleasantness of TGIP were significantly greater in patients than controls. Furthermore, positive correlations were found between TGIP intensity and clinical pain intensity and between TGIP intensity and the cold pain threshold measured on the hand. These results are consistent with our working hypothesis of shared mechanisms between TGIP and clinical pain mechanisms in patients with nociplastic chronic pain syndromes and suggest that TGIP might represent a clinical marker of central sensitization in these patients.
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Affiliation(s)
- Frédéric Adam
- Inserm U987, APHP, UVSQ, Paris-Saclay University, Ambroise Pare Hospital, Boulogne-Billancourt, France
- Department of Anesthesiology, Saint Joseph Hospital, Paris, France
| | - Pauline Jouët
- Inserm U987, APHP, UVSQ, Paris-Saclay University, Ambroise Pare Hospital, Boulogne-Billancourt, France
- Gastroenterology and Digestive Oncology Department, Avicenne Hospital, AP-HP, Bobigny, France
| | - Jean-Marc Sabaté
- Inserm U987, APHP, UVSQ, Paris-Saclay University, Ambroise Pare Hospital, Boulogne-Billancourt, France
- Gastroenterology and Digestive Oncology Department, Avicenne Hospital, AP-HP, Bobigny, France
| | - Serge Perrot
- Inserm U987, APHP, UVSQ, Paris-Saclay University, Ambroise Pare Hospital, Boulogne-Billancourt, France
- Pain Clinic, Cochin Hospital, University of Paris, Paris, France
| | - Claire Franchisseur
- Inserm U987, APHP, UVSQ, Paris-Saclay University, Ambroise Pare Hospital, Boulogne-Billancourt, France
| | - Nadine Attal
- Inserm U987, APHP, UVSQ, Paris-Saclay University, Ambroise Pare Hospital, Boulogne-Billancourt, France
| | - Didier Bouhassira
- Inserm U987, APHP, UVSQ, Paris-Saclay University, Ambroise Pare Hospital, Boulogne-Billancourt, France
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Uragami S, Osumi M. Cortical oscillatory changes during thermal grill illusion. Neuroreport 2023; 34:205-208. [PMID: 36719830 PMCID: PMC10516167 DOI: 10.1097/wnr.0000000000001874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 12/20/2022] [Indexed: 02/01/2023]
Abstract
OBJECTIVE The thermal grill illusion (TGI) can cause a burning pain sensation when the skin is subjected to simultaneously harmless hot and cold stimuli, and the pain is reported to be similar to central neuropathic pain. Although electroencephalography (EEG) is commonly used in pain research, no reports have revealed EEG activity during TGI. METHODS One healthy subject was enrolled, and EEG activity was recorded during the experience of the TGI and a warm sensation. Independent component analysis (ICA) was applied to preprocessed EEG data, which was divided into several clusters. RESULTS Theta and alpha bands in the insular cortex and parietal operculum clusters were significantly more desynchronized under the TGI condition than under the warm condition ( P < 0.05). Additionally, theta, alpha and beta bands in the frontal (middle and inferior frontal gyrus) cluster showed significantly more desynchronization under the TGI condition than under the warm condition ( P < 0.05). CONCLUSION EEG oscillations in these brain areas could be useful markers of central neuropathic pain.
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Affiliation(s)
- Shinji Uragami
- Neurorehabilitation Research Center, Kio University, Nara
- Japan Community Health care Organization Hoshigaoka Medical Center, Osaka, Japan
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Oono Y, Kubo H, Takagi S, Wang K, Arendt-Nielsen L, Kohase H. Conditioned pain modulation is not associated with thermal pain illusion. Scand J Pain 2023; 23:175-183. [PMID: 35607757 DOI: 10.1515/sjpain-2022-0037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 04/25/2022] [Indexed: 01/17/2023]
Abstract
OBJECTIVES Paradoxical sensations, known as thermal pain illusions, can be evoked by painful cold-heat pulse stimulation. They may provide diagnostic value; however, the possible interaction between conditioned pain modulation and thermal pain illusions has not been explored. The present study examined: (1) whether conditioned pain modulation could be induced by alternating tonic painful cold-heat pulse stimulation; and (2) whether the presence of thermal pain illusions during the conditioning stimulus influences the degree of conditioned pain modulation. METHODS This study was approved by the Ethics Committee of Meikai University (A1507). Conditioned pain modulation was provoked using alternating painful cold-heat pulses delivered at 20-s intervals applied to the forearm. Thermal pain illusions were qualitatively evaluated, and conditioned pain modulation was assessed quantitatively using the pressure pain threshold as a test stimulus. Differences in the conditioned pain modulation effect between the participants who experienced thermal pain illusions and those who did not were analysed using Student's t-test. RESULTS A significant positive conditioned pain modulation effect (51.0 ± 4.7%, overall effect) was detected. There was no significant difference in conditioned pain modulation between the participants who experienced thermal pain illusions and those who did not (44.3 ± 6.0% and 55.5 ± 6.8%, respectively; p = 0.255). CONCLUSIONS Conditioned pain modulation induced by alternating painful conditioning cold-heat pulse stimulation was identical during the conditioning stimulation in volunteers with and without thermal pain illusions. Conditioning cold-heat pulse stimulation is useful to evaluate conditioned pain modulation. Moreover, conditioned pain modulation is not influenced by the presence of thermal pain illusions, indicating partially different underlying supraspinal, neuronal networks.
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Affiliation(s)
- Yuka Oono
- Department of Diagnostic and Therapeutic Sciences, Division of Dental Anesthesiology, Meikai University School of Dentistry, Sakado, Japan
| | - Hidenori Kubo
- Department of Diagnostic and Therapeutic Sciences, Division of Dental Anesthesiology, Meikai University School of Dentistry, Sakado, Japan
| | - Saori Takagi
- Department of Diagnostic and Therapeutic Sciences, Division of Dental Anesthesiology, Meikai University School of Dentistry, Sakado, Japan
| | - Kelun Wang
- Center for Sensory-Motor Interaction (SMI), Department of Health Science & Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark
| | - Lars Arendt-Nielsen
- Department of Health Science and Technology, Center for Neuroplasticity and Pain, SMI, School of Medicine, Aalborg University, Aalborg, Denmark
- Department of Medical Gastroenterology, Mech-Sense, Aalborg University Hospital, Aalborg, Denmark
| | - Hikaru Kohase
- Department of Diagnostic and Therapeutic Sciences, Division of Dental Anesthesiology, Meikai University School of Dentistry, Sakado, Japan
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Osumi M, Sumitani M, Nobusako S, Sato G, Morioka S. Pain quality of thermal grill illusion is similar to that of central neuropathic pain rather than peripheral neuropathic pain. Scand J Pain 2022; 22:40-47. [PMID: 34019750 DOI: 10.1515/sjpain-2021-0020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 04/07/2021] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Application of spatially interlaced innocuous warm and cool stimuli to the skin elicits illusory pain, known as the thermal grill illusion (TGI). This study aimed to discriminate the underlying mechanisms of central and peripheral neuropathic pain focusing on pain quality, which is considered to indicate the underlying mechanism(s) of pain. We compared pain qualities in central and peripheral neuropathic pain with reference to pain qualities of TGI-induced pain. METHODS Experiment 1:137 healthy participants placed their hand on eight custom-built copper bars for 60 s and their pain quality was assessed by the McGill Pain Questionnaire. Experiment 2: Pain quality was evaluated in patients suffering from central and peripheral neuropathic pain (42 patients with spinal cord injury, 31 patients with stroke, 83 patients with trigeminal neuralgia and 131 patients with postherpetic neuralgia). RESULTS Experiment 1: Two components of TGI-induced pain were found using principal component analysis: component 1 included aching, throbbing, heavy and burning pain, component 2 included itching, electrical-shock, numbness, and cold-freezing. Experiment 2: Multiple correspondence analysis (MCA) and cross tabulation analysis revealed specific pain qualities including aching, hot-burning, heavy, cold-freezing, numbness, and electrical-shock pain were associated with central neuropathic pain rather than peripheral neuropathic pain. CONCLUSIONS We found similar qualities between TGI-induced pain in healthy participants and central neuropathic pain rather than peripheral neuropathic pain. The mechanism of TGI is more similar to the mechanism of central neuropathic pain than that of neuropathic pain.
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Affiliation(s)
- Michihiro Osumi
- Graduate School of Health Science, Kio University, Nara, Japan
- Neurorehabilitation Research Center, Kio University, Nara, Japan
| | - Masahiko Sumitani
- Department of Pain and Palliative Medicine, The University of Tokyo Hospital, Tokyo, Japan
| | - Satoshi Nobusako
- Graduate School of Health Science, Kio University, Nara, Japan
- Neurorehabilitation Research Center, Kio University, Nara, Japan
| | - Gosuke Sato
- Neurorehabilitation Research Center, Kio University, Nara, Japan
| | - Shu Morioka
- Graduate School of Health Science, Kio University, Nara, Japan
- Neurorehabilitation Research Center, Kio University, Nara, Japan
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Oono Y, Kubo H, Takagi S, Wang K, Arendt-Nielsen L, Kohase H. Painful cold-heat segmental pulse stimulation provokes the thermal pain illusion. Somatosens Mot Res 2021; 39:1-9. [PMID: 34674603 DOI: 10.1080/08990220.2021.1986382] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
PURPOSE/AIM The thermal grill illusion is a paradoxical pain sensation induced by simultaneous exposure to spatially separated, non-painful, cold, and warm stimuli. This study aimed to determine whether paradoxical sensations are also evoked by simultaneous exposure to painful cold-heat stimuli and whether the mechanism involves modulation by segmental and extra-segmental spatial integration. MATERIALS AND METHODS Sensory perceptions were triggered by simultaneous application of painful cold-heat pulse stimuli using a developed bedside tool equipped with quantitative thermal stimulator devices. Four conditions were investigated: (1) one device placed on the forearm (condition 1, control); (2) two devices placed on the forearm (condition 2, ipsilateral segmental integration); (3) two devices placed on the forearm and ipsilateral thigh (condition 3, extra-segmental integration); and (4) two devices placed bilaterally on the forearms (condition 4, contralateral segmental integration). The evoked perceptions of paradoxical heat sensation and the loss of cold or heat sensation were evaluated. RESULTS The aforementioned phenomena were experienced by 11(35.4%), 3(9.7%), 3(9.7%), and 0(0.0%) subjects for conditions 1-4, respectively. Fisher's exact test revealed significant differences (p=.001) among the four conditions. However, Bonferroni post hoc analysis revealed significant differences only between conditions 1 and 4 (p=.005). CONCLUSIONS Simultaneous painful cold-heat pulse stimulation can induce paradoxical sensations similar to those shown for non-painful thermal (cold and heat) stimuli. They were predominantly evoked by ipsilateral integration. Paradoxical sensations have diagnostic value, and quantifying them using a simple bedside tool may be useful in the clinical setting.
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Affiliation(s)
- Yuka Oono
- Department of Diagnostic and Therapeutic Sciences, Division of Dental Anesthesiology, Meikai University School of Dentistry, Sakado, Japan
| | - Hidenori Kubo
- Department of Diagnostic and Therapeutic Sciences, Division of Dental Anesthesiology, Meikai University School of Dentistry, Sakado, Japan
| | - Saori Takagi
- Department of Diagnostic and Therapeutic Sciences, Division of Dental Anesthesiology, Meikai University School of Dentistry, Sakado, Japan
| | - Kelun Wang
- Department of Health Science and Technology, School of Medicine, Center for Neuroplasticity and Pain, SMI, Aalborg University, Aalborg, Denmark
| | - Lars Arendt-Nielsen
- Department of Health Science and Technology, School of Medicine, Center for Neuroplasticity and Pain, SMI, Aalborg University, Aalborg, Denmark
| | - Hikaru Kohase
- Department of Diagnostic and Therapeutic Sciences, Division of Dental Anesthesiology, Meikai University School of Dentistry, Sakado, Japan
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Shin DA, Chang MC. A Review on Various Topics on the Thermal Grill Illusion. J Clin Med 2021; 10:jcm10163597. [PMID: 34441893 PMCID: PMC8396808 DOI: 10.3390/jcm10163597] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/11/2021] [Accepted: 08/13/2021] [Indexed: 11/16/2022] Open
Abstract
The thermal grill illusion (TGI) is a paradoxical perception of burning heat and pain resulting from the simultaneous application of interlaced warm and cold stimuli to the skin. The TGI is considered a type of chronic centralized pain and has been used to apply nociceptive stimuli without inflicting harm to human participants in the study of pain mechanisms. In addition, the TGI is an interesting phenomenon for researchers, and various topics related to the TGI have been investigated in several studies, which we will review here. According to previous studies, the TGI is generated by supraspinal interactions. To evoke the TGI, cold and warm cutaneous stimuli should be applied within the same dermatome or across dermatomes corresponding to adjacent spinal segments, and a significant difference between cold and warm temperatures is necessary. In addition, due the presence of chronic pain, genetic factors, and sexual differences, the intensity of the TGI can differ. In addition, cold noxious stimulation, topical capsaicin, analgesics, self-touch, and the presence of psychological diseases can decrease the intensity of the TGI. Because the TGI corresponds to chronic centralized pain, we believe that the findings of previous studies can be applied to future studies to identify chronic pain mechanisms and clinical practice for pain management.
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Affiliation(s)
- Dong Ah Shin
- Department of Neurosurgery, College of Medicine, Yonsei University, Seodaemun-gu, Seoul 03722, Korea;
| | - Min Cheol Chang
- Department of Physical Medicine and Rehabilitation, College of Medicine, Yeungnam University, Namku, Taegu 42415, Korea
- Correspondence: ; Tel.: +82-53-620-4682
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Rivel M, Achiron A, Dolev M, Stern Y, Zeilig G, Defrin R. Central neuropathic pain in multiple sclerosis is associated with impaired innocuous thermal pathways and neuronal hyperexcitability. PAIN MEDICINE 2021; 22:2311-2323. [PMID: 33734398 DOI: 10.1093/pm/pnab103] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE About a third of patients with multiple sclerosis (MS) suffer from chronic and excruciating central neuropathic pain (CNP). The mechanism underlying CNP in MS is not clear, since previous studies are scarce and their results are inconsistent. Our aim was to determine whether CNP in MS is associated with impairment of the spinothalamic-thalamocortical pathways (STTCs) and/or increased excitability of the pain system. DESIGN Cross sectional study. SETTING General hospital. SUBJECTS 47 MS patients with CNP, 42 MS patients without CNP, and 32 healthy controls. METHODS Sensory testing included the measurement of temperature, pain, and touch thresholds and the thermal grill illusion (TGI) for evaluating STTCs function, and hyperpathia and allodynia as indicators of hyperexcitability. CNP was characterized using interviews and questionnaires. RESULTS The CNP group had higher cold and warm thresholds (p < 0.01), as well as higher TGI perception thresholds (p < 0.05), especially in painful body regions compared to controls, whereas touch and pain thresholds values were normal. The CNP group also had a significantly greater prevalence of hyperpathia and allodynia. Regression analysis revealed that whereas presence of CNP was associated with a higher cold threshold, CNP intensity, and the number of painful body regions were associated with allodynia and hyperpathia, respectively. CONCLUSIONS CNP in MS is characterized by a specific impairment of STTC function; the innocuous thermal pathways, and by pain hyperexcitability. Whereas CNP presence is associated with STTC impairment, its severity and extent are associated with pain hyperexcitability. Interventions that reduce excitability level may therefore mitigate CNP severity.
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Affiliation(s)
- Michal Rivel
- Department of Physical Therapy, School of Health Professions, Sackler Faculty of Medicine Tel Aviv University.,Sagol School of Neuroscience, Tel-Aviv University
| | - Anat Achiron
- Multiple Sclerosis Center, Sheba Medical Center, Tel Hashomer.,Sackler Faculty of Medicine, Tel-Aviv University
| | - Mark Dolev
- Multiple Sclerosis Center, Sheba Medical Center, Tel Hashomer
| | - Yael Stern
- Multiple Sclerosis Center, Sheba Medical Center, Tel Hashomer
| | - Gaby Zeilig
- Sackler Faculty of Medicine, Tel-Aviv University.,Department of Neurological Rehabilitation, Sheba Medical Center, Tel Hashomer
| | - Ruth Defrin
- Department of Physical Therapy, School of Health Professions, Sackler Faculty of Medicine Tel Aviv University.,Sagol School of Neuroscience, Tel-Aviv University
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Forstenpointner J, Berry D, Baron R, Borsook D. The cornucopia of central disinhibition pain - An evaluation of past and novel concepts. Neurobiol Dis 2020; 145:105041. [PMID: 32800994 DOI: 10.1016/j.nbd.2020.105041] [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] [Received: 06/20/2020] [Revised: 07/18/2020] [Accepted: 08/08/2020] [Indexed: 12/12/2022] Open
Abstract
Central disinhibition (CD), as applied to pain, decreases thresholds of endogenous systems. This provokes onset of spontaneous or evoked pain in an individual beyond the ability of the nervous system to inhibit pain resulting from a disease or tissue damage. The original CD concept as proposed by Craig entails a shift from the lateral pain pathway (i.e. discriminative pain processing) towards the medial pain pathway (i.e. emotional pain processing), within an otherwise neurophysiological intact environment. In this review, the original CD concept as proposed by Craig is extended by the primary "nociceptive pathway damage - CD" concept and the secondary "central pathway set point - CD". Thereby, the original concept may be transferred into anatomical and psychological non-functional conditions. We provide examples for either primary or secondary CD concepts within different clinical etiologies as well as present surrogate models, which directly mimic the underlying pathophysiology (A-fiber block) or modulate the CD pathway excitability (thermal grill). The thermal grill has especially shown promising advancements, which may be useful to examine CD pathway activation in the future. Therefore, within this topical review, a systematic review on the thermal grill illusion is intended to stimulate future research. Finally, the authors review different mechanism-based treatment approaches to combat CD pain.
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Affiliation(s)
- Julia Forstenpointner
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Campus Kiel, Arnold-Heller-Str. 3, 24105 Kiel, Germany; Center for Pain and the Brain, Boston Children's Hospital, Department of Anesthesia, Critical Care and Pain Medicine, Harvard Medical School, Boston, MA, USA.
| | - Delany Berry
- Center for Pain and the Brain, Boston Children's Hospital, Department of Anesthesia, Critical Care and Pain Medicine, Harvard Medical School, Boston, MA, USA
| | - Ralf Baron
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Campus Kiel, Arnold-Heller-Str. 3, 24105 Kiel, Germany
| | - David Borsook
- Center for Pain and the Brain, Boston Children's Hospital, Department of Anesthesia, Critical Care and Pain Medicine, Harvard Medical School, Boston, MA, USA
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Posada-Quintero HF, Kong Y, Nguyen K, Tran C, Beardslee L, Chen L, Guo T, Cong X, Feng B, Chon KH. Using electrodermal activity to validate multilevel pain stimulation in healthy volunteers evoked by thermal grills. Am J Physiol Regul Integr Comp Physiol 2020; 319:R366-R375. [PMID: 32726157 DOI: 10.1152/ajpregu.00102.2020] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have tested the feasibility of thermal grills, a harmless method to induce pain. The thermal grills consist of interlaced tubes that are set at cool or warm temperatures, creating a painful "illusion" (no tissue injury is caused) in the brain when the cool and warm stimuli are presented collectively. Advancement in objective pain assessment research is limited because the gold standard, the self-reporting pain scale, is highly subjective and only works for alert and cooperative patients. However, the main difficulty for pain studies is the potential harm caused to participants. We have recruited 23 subjects in whom we induced electric pulses and thermal grill (TG) stimulation. The TG effectively induced three different levels of pain, as evidenced by the visual analog scale (VAS) provided by the subjects after each stimulus. Furthermore, objective physiological measurements based on electrodermal activity showed a significant increase in levels as stimulation level increased. We found that VAS was highly correlated with the TG stimulation level. The TG stimulation safely elicited pain levels up to 9 out of 10. The TG stimulation allows for extending studies of pain to ranges of pain in which other stimuli are harmful.
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Affiliation(s)
| | | | | | - Cara Tran
- University of Connecticut, Storrs, Connecticut
| | - Luke Beardslee
- Emory University School of Medicine Department of Surgery, Atlanta, Georgia
| | - Longtu Chen
- University of Connecticut, Storrs, Connecticut
| | | | | | - Bin Feng
- University of Connecticut, Storrs, Connecticut
| | - Ki H Chon
- University of Connecticut, Storrs, Connecticut
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Fardo F, Beck B, Allen M, Finnerup NB. Beyond labeled lines: A population coding account of the thermal grill illusion. Neurosci Biobehav Rev 2020; 108:472-479. [DOI: 10.1016/j.neubiorev.2019.11.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 11/21/2019] [Accepted: 11/25/2019] [Indexed: 10/25/2022]
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Cataldo A, Ferrè ER, Haggard P. Thermonociceptive interaction: interchannel pain modulation occurs before intrachannel convergence of warmth. J Neurophysiol 2019; 121:1798-1808. [PMID: 30864857 DOI: 10.1152/jn.00341.2018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nonnoxious warmth reduces both perceived pain intensity and the amplitude of EEG markers of pain. However, the spatial properties of thermonociceptive interaction, and the level of sensory processing at which it occurs, remain unclear. We investigated whether interchannel warmth-pain interactions occur before or after intrachannel spatial summation of warmth. Warm stimuli were applied to the fingers of the right hand. Their number and location were manipulated in different conditions. A concomitant noxious test pulse was delivered to the middle finger using a CO2 laser. We replicated the classical suppressive effect of warmth on both perceived pain intensity and EEG markers. Importantly, inhibition of pain was not affected by the location and the number of thermal stimuli, even though they increased the perceived intensity of warmth. Our results therefore suggest that the inhibitory effect of warmth on pain is not somatotopically organized. The results also rule out the possibility that warmth affects nociceptive processing after intrachannel warmth summation. NEW & NOTEWORTHY We used spatial summation of warmth as a model to investigate thermonociceptive interactions. Painful CO2 laser pulses were delivered during different thermal conditions. We found that warmth inhibited pain regardless of its location. Crucially, spatial summation of multiple warm stimuli did not further inhibit pain. These findings suggest that warmth-pain interaction occurs independently of or after spatial summation of warmth.
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Affiliation(s)
- Antonio Cataldo
- Institute of Cognitive Neuroscience, University College London , London , United Kingdom.,Centre for Studies and Research in Cognitive Neuroscience, Alma Mater Studiorum - University of Bologna , Cesena , Italy.,Institute of Philosophy, University of London , London , United Kingdom
| | - Elisa Raffaella Ferrè
- Department of Psychology, Royal Holloway University of London , Surrey , United Kingdom
| | - Patrick Haggard
- Institute of Cognitive Neuroscience, University College London , London , United Kingdom.,Institute of Philosophy, University of London , London , United Kingdom
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