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Kofler M, Hallett M, Iannetti GD, Versace V, Ellrich J, Téllez MJ, Valls-Solé J. The blink reflex and its modulation - Part 1: Physiological mechanisms. Clin Neurophysiol 2024; 160:130-152. [PMID: 38102022 PMCID: PMC10978309 DOI: 10.1016/j.clinph.2023.11.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Revised: 11/11/2023] [Accepted: 11/22/2023] [Indexed: 12/17/2023]
Abstract
The blink reflex (BR) is a protective eye-closure reflex mediated by brainstem circuits. The BR is usually evoked by electrical supraorbital nerve stimulation but can be elicited by a variety of sensory modalities. It has a long history in clinical neurophysiology practice. Less is known, however, about the many ways to modulate the BR. Various neurophysiological techniques can be applied to examine different aspects of afferent and efferent BR modulation. In this line, classical conditioning, prepulse and paired-pulse stimulation, and BR elicitation by self-stimulation may serve to investigate various aspects of brainstem connectivity. The BR may be used as a tool to quantify top-down modulation based on implicit assessment of the value of blinking in a given situation, e.g., depending on changes in stimulus location and probability of occurrence. Understanding the role of non-nociceptive and nociceptive fibers in eliciting a BR is important to get insight into the underlying neural circuitry. Finally, the use of BRs and other brainstem reflexes under general anesthesia may help to advance our knowledge of the brainstem in areas not amenable in awake intact humans. This review summarizes talks held by the Brainstem Special Interest Group of the International Federation of Clinical Neurophysiology at the International Congress of Clinical Neurophysiology 2022 in Geneva, Switzerland, and provides a state-of-the-art overview of the physiology of BR modulation. Understanding the principles of BR modulation is fundamental for a valid and thoughtful clinical application (reviewed in part 2) (Gunduz et al., submitted).
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Affiliation(s)
- Markus Kofler
- Department of Neurology, Hochzirl Hospital, Zirl, Austria.
| | - Mark Hallett
- National Institute of Neurological Disorders and Stroke, NIH, USA.
| | - Gian Domenico Iannetti
- University College London, United Kingdom; Italian Institute of Technology (IIT), Rome, Italy.
| | - Viviana Versace
- Department of Neurorehabilitation, Hospital of Vipiteno (SABES-ASDAA), Teaching Hospital of the Paracelsus Medical Private University (PMU), Vipiteno-Sterzing, Italy.
| | - Jens Ellrich
- Friedrich-Alexander-University Erlangen-Nuremberg, Germany.
| | | | - Josep Valls-Solé
- IDIBAPS (Institut d'Investigació August Pi i Sunyer), University of Barcelona, Spain.
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Conditioned Pain Modulation: Comparison of the Effects on Nociceptive and Non-nociceptive Blink Reflex. Neuroscience 2021; 468:168-175. [PMID: 34147564 DOI: 10.1016/j.neuroscience.2021.06.019] [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: 04/19/2021] [Revised: 05/24/2021] [Accepted: 06/11/2021] [Indexed: 11/21/2022]
Abstract
Although conditioned pain modulation (CPM) is considered to represent descending pain inhibitory mechanisms triggered by noxious stimuli applied to a remote area, there have been no previous studies comparing CPM between pain and tactile systems. In this study, we compared CPM between the two systems objectively using blink reflexes. Intra-epidermal electrical stimulation (IES) and transcutaneous electrical stimulation (TS) were applied to the right skin area over the supraorbital foramen to evoke a nociceptive or a non-nociceptive blink reflex, respectively, in 15 healthy males. In the test session, IES or TS were applied six times and subjects reported the intensity of each stimulus on a numerical rating scale (NRS). Blink reflexes were measured using electromyography (R2). The first and second sessions were control sessions, while in the third session, the left hand was immersed in cold water at 10 °C as a conditioning stimulus. The magnitude of the R2 blink and NRS scores were compared among the sessions by 2-way ANOVA. Both the NRS score and nociceptive R2 were significantly decreased in the third session for IES, with a significant correlation between the two variables; whereas, TS-induced non-nociceptive R2 did not change among the sessions. Although the conditioning stimulus decreased the NRS score for TS, the CPM effect was significantly smaller than that for IES (p = 0.002). The present findings suggest the presence of a pain-specific CPM effect to a heterotopic noxious stimulus.
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Versace V, Campostrini S, Sebastianelli L, Saltuari L, Valls-Solé J, Kofler M. Threat vs control: Potentiation of the trigeminal blink reflex by threat proximity is overruled by self-stimulation. Psychophysiology 2020; 57:e13626. [PMID: 32573801 DOI: 10.1111/psyp.13626] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 04/21/2020] [Accepted: 05/19/2020] [Indexed: 11/27/2022]
Abstract
The magnitude of the defensive blink reflex is modulated by continuous assessment of its protective value. Here, we studied whether the trigeminal blink reflex (TBR) is modulated by a potentially offensive object close to the face, and, if so, whether self-stimulation or observation of the act of stimulus triggering counteracts such modulation. In all, 26 healthy volunteers participated in various experimental conditions. At baseline, an experimenter triggered supraorbital nerve stimuli remotely, unseen by the participants; in experimental conditions, the experimenter held a stimulation probe close to the participant's face but triggered the stimuli either remotely, "surprising" participants (S1 ), or directly on the probe, observed by participants (S2 ). In other conditions, participants triggered stimuli themselves on the probe held next to their body (S3 ) or held in front of their face (S4 ). The latter condition was repeated similarly, but pressing the button only randomly generated electrical stimuli (S5, "Russian roulette"). The size of the R2 component of the TBR (TBR-R2) was the main outcome measure. Compared to baseline, TBR-R2 area was significantly larger in S1 when the "threatening" probe was close to the face and the participant had no control over stimulation. Conversely, TBR-R2 was suppressed when participants either saw the action of triggering, thus being aware (S2 ), or had full initiative over stimulation (S3 , S4 ). Random self-generated stimuli (S5 ) inhibited TBR-R2, but to a lesser extent than S3 and S4. Perceived threat close to the face facilitates TBR-R2, but knowledge about impending stimulation or self-agency overrules this effect.
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Affiliation(s)
- Viviana Versace
- Department of Neurorehabilitation, Hospital of Vipiteno/Sterzing, Vipiteno/Sterzing, Italy.,Research Unit for Neurorehabilitation of South Tyrol, Bolzano/Bozen, Italy
| | - Stefania Campostrini
- Department of Neurorehabilitation, Hospital of Vipiteno/Sterzing, Vipiteno/Sterzing, Italy.,Research Unit for Neurorehabilitation of South Tyrol, Bolzano/Bozen, Italy
| | - Luca Sebastianelli
- Department of Neurorehabilitation, Hospital of Vipiteno/Sterzing, Vipiteno/Sterzing, Italy.,Research Unit for Neurorehabilitation of South Tyrol, Bolzano/Bozen, Italy
| | - Leopold Saltuari
- Research Unit for Neurorehabilitation of South Tyrol, Bolzano/Bozen, Italy.,Department of Neurology, Hochzirl Hospital, Zirl, Austria
| | - Josep Valls-Solé
- IDIBAPS (Institut d'Investigació August Pi i Sunyer), Facultat de Medicina, University of Barcelona, Barcelona, Spain
| | - Markus Kofler
- Department of Neurology, Hochzirl Hospital, Zirl, Austria
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Williams AE, Miller MM, Bartley EJ, McCabe KM, Kerr KL, Rhudy JL. Impairment of Inhibition of Trigeminal Nociception via Conditioned Pain Modulation in Persons with Migraine Headaches. PAIN MEDICINE (MALDEN, MASS.) 2019; 20:1600-1610. [PMID: 30690591 PMCID: PMC7963204 DOI: 10.1093/pm/pny305] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To assess conditioned pain modulation efficiency in persons with and without migraine headaches. DESIGN Cross-sectional assessment of experimental pain. SETTING University campus and surrounding community in a large Midwestern US city. SUBJECTS Twenty-three adults with and 32 without a history of migraine headaches participated in the study. Participants were mostly female (N = 40) with an average age of 23 years. METHODS Four electrocutaneous stimulations of the supraorbital branch of the left trigeminal nerve were delivered at 150% of an individually determined pain threshold. Conditioned pain modulation was assessed by applying a noxious counterstimulus (forearm ischemia) and delivering four more electrocutaneous stimulations. After each stimulation, pain and the nociceptive blink reflex were assessed. Depression and pain catastrophizing were assessed to control for the potential influence of these variables on pain modulation. RESULTS Participants with and without migraine headaches had similar baseline pain responsivity, without significant differences in pain report or nociceptive blink reflexes. Pain report was inhibited by conditioned pain modulation in both the migraine and control groups. However, unlike nonmigraine controls, participants with migraines did not exhibit an inhibition of nociceptive blink reflexes during the ischemia task. This pattern persisted after controlling for level of pain catastrophizing and depression. CONCLUSIONS Migraine sufferers exhibited impaired conditioned pain modulation of the nociceptive blink reflex, suggesting a deficiency in inhibition of trigeminal nociception, which may contribute to the development of migraine headaches.
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Affiliation(s)
- Amy E Williams
- Department of Psychiatry, Riley Child and Adolescent Psychiatry Clinic, Indiana University School of Medicine, Indiana University Health Physicians, Indianapolis, Indiana
| | - Megan M Miller
- Department of Psychology, Indiana University–Purdue University Indianapolis, Indianapolis, Indiana
| | - Emily J Bartley
- Department of Community Dentistry and Behavioral Science, Pain Research & Intervention Center of Excellence (PRICE), University of Florida, Gainesville, Florida
| | - Klanci M McCabe
- Section of Psychology, Division of Developmental and Behavioral Sciences, Children’s Mercy Kansas City, University of Missouri Kansas City School of Medicine, Kansas City, Missouri
| | - Kara L Kerr
- Department of Human Development and Family Science, Oklahoma State University, Tulsa, Oklahoma
- Laureate Institute for Brain Research, Tulsa, Oklahoma
| | - Jamie L Rhudy
- Department of Psychology, The University of Tulsa, Tulsa, Oklahoma, USA
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Abstract
Clinical neurophysiologic investigation of pain pathways in humans is based on specific techniques and approaches, since conventional methods of nerve conduction studies and somatosensory evoked potentials do not explore these pathways. The proposed techniques use various types of painful stimuli (thermal, laser, mechanical, or electrical) and various types of assessments (measurement of sensory thresholds, study of nerve fiber excitability, or recording of electromyographic reflexes or cortical potentials). The two main tests used in clinical practice are quantitative sensory testing and pain-related evoked potentials (PREPs). In particular, PREPs offer the possibility of an objective assessment of nociceptive pathways. Three types of PREPs can be distinguished depending on the type of stimulation used to evoke pain: laser-evoked potentials, contact heat evoked potentials, and intraepidermal electrical stimulation evoked potentials (IEEPs). These three techniques investigate both small-diameter peripheral nociceptive afferents (mainly Aδ nerve fibers) and spinothalamic tracts without theoretically being able to differentiate the level of lesion in the case of abnormal results. In routine clinical practice, PREP recording is a reliable method of investigation for objectifying the existence of a peripheral or central lesion or loss of function concerning the nociceptive pathways, but not the existence of pain. Other methods, such as nerve fiber excitability studies using microneurography, more directly reflect the activities of nociceptive axons in response to provoked pain, but without detecting or quantifying the presence of spontaneous pain. These methods are more often used in research or experimental study design. Thus, it should be kept in mind that most of the results of neurophysiologic investigation performed in clinical practice assess small fiber or spinothalamic tract lesions rather than the neuronal mechanisms directly at the origin of pain and they do not provide objective quantification of pain.
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Affiliation(s)
- Jean-Pascal Lefaucheur
- Excitabilité Nerveuse et Thérapeutique, Faculté de Médecine de Créteil, Université Paris-Est-Créteil, Hôpital Henri Mondor, Créteil, France; Service de Physiologie-Explorations Fonctionnelles, Hôpital Henri Mondor, Créteil, France.
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Painful stimulation of a sensitized site in the forearm inhibits ipsilateral trigeminal nociceptive blink reflexes. Exp Brain Res 2018; 236:2097-2105. [PMID: 29754196 DOI: 10.1007/s00221-018-5255-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 04/06/2018] [Indexed: 10/16/2022]
Abstract
Exposure to moderate levels of ultraviolet B radiation (UVB) is painless but nevertheless induces an inflammatory response that sensitizes primary afferent nociceptors. Subsequently, heating the UVB-treated site can sensitize spinal nociceptors. We used a repeated-measures design to determine whether heating the UVB-treated site also triggers ipsilateral inhibitory controls. Specifically, a 2-cm diameter site on the forearm of 20 participants was exposed to UVB at twice the minimum erythema dose. 48 h later mechanical and thermal sensitivity had increased at the UVB-treated site, indicating primary hyperalgesia. In addition, sensitivity to blunt pressure had increased in the ipsilateral forehead, implying activation of an ipsilateral supra-spinal pro-nociceptive mechanism. Despite this, the area under the curve of the ipsilateral nociceptive blink reflex decreased when the UVB-treated site was heated to induce moderate pain. Together, these findings suggest that the UVB treatment sensitized primary nociceptive afferents and generated an ipsilateral supra-spinal pro-nociceptive mechanism. In addition, sensitization to heat induced by the UVB treatment strengthened an ipsilateral anti-nociceptive process elicited by heat-pain. Infrequent but enduring discharge of sensitized primary nociceptive afferents, driven by inflammation after UVB exposure, might initiate a lateralized supra-spinal pro-nociceptive influence that heightens awareness of impending harm on the sensitized side of the body. In addition, a lateralized anti-nociceptive response triggered by an intense barrage of nociceptive signals may help to differentiate stronger from weaker sources of pain.
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Reliability of the nociceptive blink reflex evoked by electrical stimulation of the trigeminal nerve in humans. Clin Oral Investig 2017; 21:2453-2463. [PMID: 28074292 DOI: 10.1007/s00784-016-2042-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 12/21/2016] [Indexed: 02/03/2023]
Abstract
OBJECTIVE The nociceptive blink reflex (nBR) can be useful to investigate trigeminal nociceptive function. The aim of this study was to estimate the reliability of the nBR evoked by electrical stimulation of the three branches of the trigeminal nerve under the following conditions: over time (test-retest and intrarater reliability) and by two examiners (interrater reliability). MATERIALS AND METHODS Twenty-one healthy participants were evaluated in two sessions (24 h apart). The nBR was elicited by a so-called "nociceptive-specific" electrode placed over the entry zone of the right supraorbital (V1R), infraorbital (V2R), mental (V3R), and left infraorbital (V2L) nerve. The outcomes were individual electrical sensory (I 0) and pain thresholds (I P); root mean square (RMS), area-under-the-curve (AUC), and onset latencies of R2 responses (determined twice after a recalibration session); and stimulus-evoked pain on a 0-10 numerical rating scale. Intraclass correlation coefficients (ICCs) and Kappa statistics were computed (α = 5%). RESULTS ICCs were fair to excellent in 82% of the psychophysical measures (fair 21%, good 31%, excellent 30%) and in 86% of V1R, V2R, and V2L nBR parameters, whereas 52% of V3R showed poor reliability. ICCs for intrarater reliability were fair to good in 70% of measurements (fair 20%, good 50%) and in 75% of interrater measurements after the recalibration (fair 55%, good 20%). All kappa values showed at least fair agreement and the majority of the nBR measures (93%) presented moderate to excellent reliability. CONCLUSION The nBR and its associated psychophysical measures can be considered a sufficiently reliable test. CLINICAL SIGNIFICANCE The nBR can be recommended as an electrophysiological technique to assess trigeminal nociceptive function.
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Abstract
The neural mechanisms of the powerful analgesia induced by touching a painful body part are controversial. A long tradition of neurophysiologic studies in anaesthetized spinal animals indicate that touch can gate nociceptive input at spinal level. In contrast, recent studies in awake humans have suggested that supraspinal mechanisms can be sufficient to drive touch-induced analgesia. To investigate this issue, we evaluated the modulation exerted by touch on established electrophysiologic markers of nociceptive function at both subcortical and cortical levels in humans. Aδ and C skin nociceptors were selectively activated by high-power laser pulses. As markers of subcortical and cortical function, we recorded the laser blink reflex, which is generated by brainstem circuits before the arrival of nociceptive signals at the cortex, and laser-evoked potentials, which reflect neural activity of a wide array of cortical areas. If subcortical nociceptive responses are inhibited by concomitant touch, supraspinal mechanisms alone are unlikely to be sufficient to drive touch-induced analgesia. Touch induced a clear analgesic effect, suppressed the laser blink reflex, and inhibited both Aδ-fibre and C-fibre laser-evoked potentials. Thus, we conclude that touch-induced analgesia is likely to be mediated by a subcortical gating of the ascending nociceptive input, which in turn results in a modulation of cortical responses. Hence, supraspinal mechanisms alone are not sufficient to mediate touch-induced analgesia.
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Coppola G, Di Clemente L, Fumal A, Magis D, De Pasqua V, Pierelli F, Schoenen J. Inhibition of the Nociceptive R2 Blink Reflex after Supraorbital or Index Finger Stimulation is Normal in Migraine Without Aura Between Attacks. Cephalalgia 2016; 27:803-8. [PMID: 17598762 DOI: 10.1111/j.1468-2982.2007.01323.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In order to explore possible interictal brainstem dysfunctions in migraine, we have studied the R2 component of the nociceptive specific blink reflex (nBR) after conditioning by supraorbital or index finger stimuli in 14 untreated migraine without aura patients (MO) between attacks and in 15 healthy volunteers. We determined the R2 recovery curve at increasing inter-stimulus intervals between 50 and 600 ms. The nBR was conditioned by a paired supraorbital stimulus and, in another session, by an ipsilateral electrical shock delivered to the index finger. The R2 nBR recovery curves were normal in MO patients for both the supraorbital and peripheral conditioning. These results do not favour persistent interictal sensitization in the spinal trigeminal sensory system. They also suggest that the control exerted by descending brainstem pathways on medullary R2 interneurones is normal in migraine between attacks.
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Affiliation(s)
- G Coppola
- G.B. Bietti Eye Foundation-IRCCS, Department of Neurophysiology of Vision and Neurophthalmology, Rome, Italy
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Marin JCA, Gantenbein AR, Paemeleire K, Kaube H, Goadsby PJ. Nociception-specific blink reflex: pharmacology in healthy volunteers. J Headache Pain 2015; 16:87. [PMID: 26449227 PMCID: PMC4598330 DOI: 10.1186/s10194-015-0568-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 09/02/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The physiology and pharmacology of activation or perception of activation of pain-coding trigeminovascular afferents in humans is fundamental to understanding the biology of headache and developing new treatments. METHODS The blink reflex was elicited using a concentric electrode and recorded in four separate sessions, at baseline and two minutes after administration of ramped doses of diazepam (final dose 0.07 mg/kg), fentanyl (final dose 1.11 μg/kg), ketamine (final dose 0.084 mg/kg) and 0.9 % saline solution. The AUC (area under the curve, μV*ms) and the latency (ms) of the ipsi- and contralateral R2 component of the blink reflex were calculated by PC-based offline analysis. Immediately after each block of blink reflex recordings certain psychometric parameters were assessed. RESULTS There was an effect due to DRUG on the ipsilateral (F 3,60 = 7.3, P < 0.001) AUC as well as on the contralateral (F 3,60 = 6.02, P < 0.001) AUC across the study. A significant decrement in comparison to placebo was observed only for diazepam, affecting the ipsilateral AUC. The scores of alertness, calmness, contentedness, reaction time and precision were not affected by the DRUG across the sessions. CONCLUSION Previous studies suggest central, rather than peripheral changes in nociceptive trigeminal transmission in migraine. This study demonstrates a robust effect of benzodiazepine receptor modulation of the nociception specific blink reflex (nBR) without any μ-opiate or glutamate NMDA receptor component. The nociception specific blink reflex offers a reproducible, quantifiable method of assessment of trigeminal nociceptive system in humans that can be used to dissect pharmacology relevant to primary headache disorders.
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Affiliation(s)
- J C A Marin
- NIHR-Wellcome Trust King's Clinical Research Facility, King's College Hospital, London, UK
| | - A R Gantenbein
- NIHR-Wellcome Trust King's Clinical Research Facility, King's College Hospital, London, UK
- Current address: Neurorehabilitation Center, RehaClinic, Bad Zurzach, Switzerland
- Current address: University of Zurich, Zürich, Switzerland
| | - K Paemeleire
- NIHR-Wellcome Trust King's Clinical Research Facility, King's College Hospital, London, UK
- Current address: Department of Neurology, Ghent University Hospital, Ghent, Belgium
| | - H Kaube
- NIHR-Wellcome Trust King's Clinical Research Facility, King's College Hospital, London, UK
- Neurology and Headache Center, Munich, Germany
| | - P J Goadsby
- NIHR-Wellcome Trust King's Clinical Research Facility, King's College Hospital, London, UK.
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College, London, UK.
- Wellcome Foundation Building, King's College Hospital, London, SE5 9PJ, UK.
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Racine M, Tousignant-Laflamme Y, Kloda LA, Dion D, Dupuis G, Choinière M. A systematic literature review of 10 years of research on sex/gender and experimental pain perception - part 1: are there really differences between women and men? Pain 2012; 153:602-618. [PMID: 22192712 DOI: 10.1016/j.pain.2011.11.025] [Citation(s) in RCA: 441] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 11/15/2011] [Accepted: 11/22/2011] [Indexed: 01/08/2023]
Abstract
The purpose of this systematic review was to summarize and critically appraise the results of 10 years of human laboratory research on pain and sex/gender. An electronic search strategy was designed by a medical librarian and conducted in multiple databases. A total of 172 articles published between 1998 and 2008 were retrieved, analyzed, and synthesized. The first set of results (122 articles), which is presented in this paper, examined sex difference in the perception of laboratory-induced thermal, pressure, ischemic, muscle, electrical, chemical, and visceral pain in healthy subjects. This review suggests that females (F) and males (M) have comparable thresholds for cold and ischemic pain, while pressure pain thresholds are lower in F than M. There is strong evidence that F tolerate less thermal (heat, cold) and pressure pain than M but it is not the case for tolerance to ischemic pain, which is comparable in both sexes. The majority of the studies that measured pain intensity and unpleasantness showed no sex difference in many pain modalities. In summary, 10 years of laboratory research have not been successful in producing a clear and consistent pattern of sex differences in human pain sensitivity, even with the use of deep, tonic, long-lasting stimuli, which are known to better mimic clinical pain. Whether laboratory studies in healthy subjects are the best paradigm to investigate sex differences in pain perception is open to question and should be discussed with a view to enhancing the clinical relevance of these experiments and developing new research avenues.
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Affiliation(s)
- Mélanie Racine
- Department of Psychology, Université du Québec à Montréal, Montreal, Quebec, Canada Centre de recherche, Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, Quebec, Canada École de réadaptation, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Quebec, Canada Life Sciences Library, McGill University, Montreal, Quebec, Canada Department of Family Medicine and Emergency, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada Research Centre, Montreal Heart Institute, Montreal, Quebec, Canada Department of Anaesthesiology, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada
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Lefaucheur JP, Ahdab R, Ayache SS, Lefaucheur-Ménard I, Rouie D, Tebbal D, Neves DO, Ciampi de Andrade D. Pain-related evoked potentials: a comparative study between electrical stimulation using a concentric planar electrode and laser stimulation using a CO2 laser. Neurophysiol Clin 2012; 42:199-206. [PMID: 22632868 DOI: 10.1016/j.neucli.2011.12.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2011] [Revised: 11/28/2011] [Accepted: 12/18/2011] [Indexed: 11/26/2022] Open
Abstract
OBJECTIVE To compare the pain-related evoked potentials (PREPs) obtained by superficial electrical stimulation using a concentric planar electrode to those obtained by CO2 laser stimulation. METHODS In 12 healthy subjects, PREPs, sympathetic skin reflexes (SSRs), motor reaction times (mRTs), and the conduction velocity (CV) of the recruited nerve fibres were assessed in response to electrical and laser stimulation. RESULTS In response to superficial electrical stimulation, PREP latencies and mRTs were shorter, while PREP amplitude tended to be increased. By contrast, SSR amplitudes and latencies and estimated CVs of the stimulated nerve fibres did not differ between electrical and laser stimulation. Fifteen minutes after PREP recordings, the residual pain intensity and the degree of unpleasantness were higher for laser stimulation than for electrical stimulation. In addition, CO2 laser stimuli induced dyschromic spots on the skin. For these reasons, all subjects declared that they would prefer superficial electrical stimulation rather than CO2 laser stimulation if they had to perform PREPs again. CONCLUSIONS The estimated CVs of the recruited nerve fibres and the localized pinprick sensation felt by the subjects suggest that small-diameter fibres in the A-delta range, conveying "first-pain" information, were stimulated in response to superficial electrical stimulation as for laser stimulation. Superficial electrical stimulation using a concentric planar electrode could be a valuable alternative to laser stimulation for assessing PREPs in the practice of clinical neurophysiology.
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Affiliation(s)
- J P Lefaucheur
- EA 4391, excitabilité nerveuse et thérapeutique, université Paris-Est Créteil, 94010 Créteil cedex, France.
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Otsuru N, Inui K, Yamashiro K, Miyazaki T, Takeshima Y, Kakigi R. Assessing Aδ Fiber Function With Lidocaine Using Intraepidermal Electrical Stimulation. THE JOURNAL OF PAIN 2010; 11:621-7. [DOI: 10.1016/j.jpain.2009.10.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Revised: 07/09/2009] [Accepted: 10/02/2009] [Indexed: 10/20/2022]
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Téllez MJ, Axelrod F, Kaufmann H. The R3 component of the electrically elicited blink reflex is present in patients with congenital insensitivity to pain. Pain 2008; 141:178-80. [PMID: 19084335 DOI: 10.1016/j.pain.2008.10.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Revised: 10/22/2008] [Accepted: 10/30/2008] [Indexed: 10/21/2022]
Abstract
To clarify whether the R3 component of the electrically elicited blink reflex is a nociceptive response we studied two patients with congenital insensitivity to pain due to the impaired development of Adelta and C nerve fibers (hereditary sensory and autonomic neuropathy types III and IV). We postulated that if the R3 component is a nociceptive reflex, it should be absent in these patients. The R3 responses were elicited in both sides in both the patients at all intensities, strongly suggesting that the R3 component of the blink reflex is not a nociceptive response.
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Affiliation(s)
- Maria J Téllez
- Dysautonomia Research Laboratory, Department of Neurology, NYU School of Medicine, 530 First Avenue, 9Q, New York, NY 10016, USA.
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Cruccu G, Iannetti GD, Truini A. Chapter 28 Brainstem reflexes and their relevance to pain. HANDBOOK OF CLINICAL NEUROLOGY 2006; 81:411-IX. [PMID: 18808850 DOI: 10.1016/s0072-9752(06)80032-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Cruccu G, Biasiotta A, Galeotti F, Iannetti GD, Innocenti P, Romaniello A, Truini A. Chapter 14 Diagnosis of trigeminal neuralgia: a new appraisal based on clinical and neurophysiological findings. ACTA ACUST UNITED AC 2006; 58:171-86. [PMID: 16623330 DOI: 10.1016/s1567-424x(09)70067-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Affiliation(s)
- G Cruccu
- Department of Neurological Sciences, "La Sapienza" University, 00185 Rome, Italy.
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Peddireddy A, Wang K, Svensson P, Arendt-Nielsen L. Effect of experimental posterior temporalis muscle pain on human brainstem reflexes. Clin Neurophysiol 2005; 116:1611-20. [PMID: 15953560 DOI: 10.1016/j.clinph.2005.02.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2004] [Revised: 02/21/2005] [Accepted: 02/23/2005] [Indexed: 01/19/2023]
Abstract
OBJECTIVE To study the modulation of jaw-stretch and blink reflexes by experimental posterior temporalis muscle pain. METHODS Thirty healthy volunteers (15 males, 25.5+/-0.6 years and 15 females, 27.4 +/- 1.2 years) were included. Short-latency stretch reflex responses were evoked in the masseter and temporalis muscles by fast stretches (1 mm displacement, 10 ms ramp time) and the blink reflexes were evoked by painful electrical pulses (0.5 ms duration), delivered by a concentric electrode placed on the left lower forehead close to the supraorbital foramen before, during and 15 min after a period with experimentally induced muscle pain. RESULTS The normalized peak-to-peak amplitude of the stretch reflex in the painful temporalis was significantly higher during pain in both males and females compared with pre- and post-pain conditions (P < 0.004). The R2 root mean square (RMS) of the blink reflex decreased significantly during muscle pain as compared to the pre-pain (P < 0.03) in both males and females. CONCLUSIONS The present results indicated that experimental posterior temporalis muscle pain facilitates the jaw-stretch reflex, whereas the nociceptive specific blink reflex is inhibited. SIGNIFICANCE Present study suggested that these reflexes are suitable models for probing pontine and medullary pain processing.
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Affiliation(s)
- Anitha Peddireddy
- Orofacial Pain Laboratory, Center for Sensory-Motor Interaction, Aalborg University, Fredrik Bajars Vej 7D-3, 9220 Aalborg, Denmark
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Abstract
The majority of the studies on laser evoked potentials (LEPs) have been focused on hand and foot stimulations and only lately on the trigeminal system. Because of a high receptor density in the facial skin and the very short conduction distance, LEP recordings after trigeminal stimulation are easier and quicker than those after stimulation of the limb extremities. Laser pulses with a stimulus intensity close to perception threshold can evoke well-defined LEPs. Few trials are sufficient to yield stable and reproducible averages. Even ultralate LEPs related to the C-fibre input are comparatively easily obtained from the trigeminal territory. The brain generators of the main LEP waves are probably very close for the trigeminal and limb stimulations. Trigeminal LEPs have been found absent or delayed in patients with trigeminal neuralgia, trigeminal neuropathies, posterior fossa tumors, and brainstem infarctions or demyelinating plaques. Conversely, trigeminal LEPs appear to be enhanced in patients with migraine. High-intensity pulses directed to any trigeminal division also elicit reflex responses: a blink-like reflex in the orbicularis oculi and a single silent period in the contracting masseter muscle. The availability of a neurophysiological method of assessing function of the trigeminal nociceptive pathways reaching both the cerebral cortex and the brainstem reflex circuits, has provided new opportunities for investigating the pathophysiology of orofacial pain syndromes.
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Affiliation(s)
- A Romaniello
- Department of Neurological Sciences, University La Sapienza, Viale Università 30, 00185 Rome, Italy
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Romaniello A, Cruccu G, Frisardi G, Arendt-Nielsen L, Svensson P. Assessment of nociceptive trigeminal pathways by laser-evoked potentials and laser silent periods in patients with painful temporomandibular disorders. Pain 2003; 103:31-9. [PMID: 12749956 DOI: 10.1016/s0304-3959(02)00347-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We assessed the trigeminal nociceptive pathways in patients with painful temporomandibular disorders (TMD) and control subjects using a CO(2)-laser stimulator which provides a predominant activation of the nociceptive system. Fifteen patients with unilateral pain were examined in accordance with the Research Diagnostic Criteria for TMD and 30 gender- and age-matched individuals were included as a control group. Laser-evoked potentials (LEPs) and laser silent periods (LSPs) after stimulation of the perioral region (V2/V3) on the painful and non-painful sides were recorded in all subjects. LEPs were evoked by low-intensity pulses (1.5 x perception threshold (PTh)) and recorded from scalp electrodes at the vertex. LSPs were evoked by high-intensity pulses (4 x PTh) and recorded bilaterally from masseter muscles with surface electromyogram (EMG) electrodes. Subjects also assessed the stimulus intensity on a 0-10 rating scale. LEPs had normal latency but smaller amplitude in TMD patients compared to the control group (P<0.001). Side-to-side comparison within patients showed that LEP amplitude was even more reduced after stimulation on the painful than the non-painful side (P<0.001). TMD patients showed a significant side-asymmetry of the pre-stimulus EMG activity, with a smaller value in the muscle on the painful side (P<0.001). LSPs were completely absent bilaterally in 12 TMD patients and unilaterally in two patients; only one patient had normal and bilateral LSPs. TMD patients perceived the laser stimulus less intense on the painful than the non-painful side (P<0.05). We found suppression of cortical responses and brainstem reflexes elicited by a predominantly nociceptive input in TMD patients. These findings are consistent with recent experimental pain studies and suggest that chronic craniofacial pain in TMD patients may be associated with a dysfunction of the trigeminal nociceptive system.
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Affiliation(s)
- A Romaniello
- Center for Sensory-Motor Interaction, Orofacial Pain Laboratory, Aalborg University, Aalborg, Denmark
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Iannetti GD, Truini A, Romaniello A, Galeotti F, Rizzo C, Manfredi M, Cruccu G. Evidence of a specific spinal pathway for the sense of warmth in humans. J Neurophysiol 2003; 89:562-70. [PMID: 12522202 DOI: 10.1152/jn.00393.2002] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
While research on human sensory processing shows that warm input is conveyed from the periphery by specific, unmyelinated primary sensory neurons, its pathways in the central nervous system (CNS) remain unclear. To gain physiological information on the spinal pathways that convey warmth or nociceptive sensations, in 15 healthy subjects, we studied the cerebral evoked responses and reaction times in response to laser stimuli selectively exciting Adelta nociceptors or C warmth receptors at different levels along the spine. To minimize the conduction distance along the primary sensory neuron, we directed CO(2)-laser pulses to the skin overlying the vertebral spinous processes. Using brain source analysis of the evoked responses with high-resolution electroencephalography and a realistic model of the head based on individual magnetic resonance imaging scans, we also studied the cortical areas involved in the cerebral processing of warm and nociceptive inputs. The activation of C warmth receptors evoked cerebral potentials with a main positive component peaking at 470-540 ms, i.e., a latency clearly longer than that of the corresponding wave yielded by Adelta nociceptive input (290-320 ms). Spinal neurons activated by the warm input had a slower conduction velocity (2.5 m/s) than the nociceptive spinal neurons (11.9 m/s). Brain source analysis of the cerebral responses evoked by the Adelta input yielded a very strong fit for one single generator in the mid portion of the cingulate gyrus; the warmth-related responses were best explained by three generators, one within the cingulate and two in the right and left opercular-insular cortices. Our results support the existence of slow-conducting second-order neurons specific for the sense of warmth.
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Affiliation(s)
- G D Iannetti
- Dipartimento Scienze Neurologiche, Università La Sapienza, 00185 Rome, Italy
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Cervera A, Veciana M, Valls-Solé J. Sympathetic sudomotor skin responses induced by laser stimuli in normal human subjects. Neurosci Lett 2002; 334:115-8. [PMID: 12435485 DOI: 10.1016/s0304-3940(02)01117-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Laser stimuli (LS) were used to induce sudomotor skin responses (SSRs) in ten healthy human subjects. LS were applied to the dorsum of the hand by means of a CO(2) laser stimulator at an intensity of 120% pain perception threshold. SSRs induced by LS were of longer latency than those induced by electrical stimuli. However, response amplitude and duration were similar with either stimuli. The possibility to activate the sudomotor system by means of stimulation of pain afferents might be of clinical applicability for the functional assessment of pain pathways.
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Affiliation(s)
- Alvaro Cervera
- Unitat d'EMG, Servei de Neurologia, Hospital Cli;nic, Facultad de Medicina, Universitat de Barcelona, Institut d'Investigació Biomédica August Pi i Sunyer, Villarroel, 170, Barcelona, 08036, Spain
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