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Ogalo E, Linde LD, Ro H, Ortiz O, Kramer JLK, Berger MJ. Evaluating peripheral neuromuscular function with brief movement-evoked pain. J Neurophysiol 2024; 131:789-796. [PMID: 38353653 PMCID: PMC11383610 DOI: 10.1152/jn.00472.2023] [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: 12/20/2023] [Revised: 02/01/2024] [Accepted: 02/11/2024] [Indexed: 04/24/2024] Open
Abstract
Movement-evoked pain is an understudied manifestation of musculoskeletal conditions that contributes to disability, yet little is known about how the neuromuscular system responds to movement-evoked pain. The present study examined whether movement-evoked pain impacts force production, electromyographic (EMG) muscle activity, and the rate of force development (RFD) during submaximal muscle contractions. Fifteen healthy adults (9 males; age = 30.3 ± 10.2 yr, range = 22-59 yr) performed submaximal isometric first finger abduction contractions without pain (baseline) and with movement-evoked pain induced by laser stimulation to the dorsum of the hand. Normalized force (% maximal voluntary contraction) and RFD decreased by 11% (P < 0.001) and 15% (P = 0.003), respectively, with movement-evoked pain, without any change in normalized peak EMG (P = 0.77). Early contractile RFD, force impulse, and corresponding EMG amplitude computed within time segments of 50, 100, 150, and 200 ms relative to the onset of movement were also unaffected by movement-evoked pain (P > 0.05). Our results demonstrate that movement-evoked pain impairs peak characteristics and not early measures of submaximal force production and RFD, without affecting EMG activity (peak and early). Possible explanations for the stability in EMG with reduced force include antagonist coactivation and a reorganization of motoneuronal activation strategy, which is discussed here.NEW & NOTEWORTHY We provide neurophysiological evidence to indicate that peak force and rate of force development are reduced by movement-evoked pain despite a lack of change in EMG and early rapid force development in the first dorsal interosseous muscle. Additional evidence suggests that these findings may coexist with a reorganization in motoneuronal activation strategy.
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Affiliation(s)
- Emmanuel Ogalo
- International Collaboration on Repair Discoveries (ICORD), Vancouver, British Columbia, Canada
- Department of Anesthesiology, Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Lukas D Linde
- International Collaboration on Repair Discoveries (ICORD), Vancouver, British Columbia, Canada
| | - Hannah Ro
- International Collaboration on Repair Discoveries (ICORD), Vancouver, British Columbia, Canada
| | - Oscar Ortiz
- International Collaboration on Repair Discoveries (ICORD), Vancouver, British Columbia, Canada
| | - John L K Kramer
- International Collaboration on Repair Discoveries (ICORD), Vancouver, British Columbia, Canada
- Department of Anesthesiology, Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Michael J Berger
- International Collaboration on Repair Discoveries (ICORD), Vancouver, British Columbia, Canada
- Division of Physical Medicine and Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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Allmendinger F, Scheuren PS, De Schoenmacker I, Brunner F, Rosner J, Curt A, Hubli M. Contact-Heat Evoked Potentials: Insights into Pain Processing in CRPS Type I. J Pain Res 2024; 17:989-1003. [PMID: 38505501 PMCID: PMC10949273 DOI: 10.2147/jpr.s436645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 02/23/2024] [Indexed: 03/21/2024] Open
Abstract
Purpose The pathophysiological mechanisms underlying the development of chronic pain in complex regional pain syndrome (CRPS) are diverse and involve both peripheral and central changes in pain processing, such as sensitization of the nociceptive system. The aim of this study was to objectively distinguish the specific changes occurring at both peripheral and central levels in nociceptive processing in individuals with chronic CRPS type I. Patients and Methods Nineteen individuals with chronic CRPS type I and 16 age- and sex-matched healthy controls (HC) were recruited. All individuals underwent a clinical examination and pain assessment in the most painful limb, the contralateral limb, and a pain-free control area to distinguish between peripheral and central mechanisms. Contact-heat evoked potentials (CHEPs) were recorded after heat stimulation of the three different areas and amplitudes and latencies were analyzed. Additionally, quantitative sensory testing (QST) was performed in all three areas. Results Compared to HC, CHEP amplitudes in CRPS were only increased after stimulation of the painful area (p=0.025), while no increases were observed for the pain-free control area (p=0.14). None of the CHEP latencies were different between the two cohorts (all p>0.23). Furthermore, individuals with CRPS showed higher pain ratings after stimulation of the painful limb compared to their contralateral limb (p=0.013). Lastly, compared to HC, mechanical (p=0.012) and thermal (p=0.046) sensitivity was higher in the painful area of the CRPS cohort. Conclusion This study provides neurophysiological evidence supporting an intact thermo-nociceptive pathway with signs of peripheral sensitization, such as hyperexcitable primary afferent nociceptors, in individuals with CRPS type I. This is further supported by the observation of mechanical and thermal gain of sensation only in the painful limb. Additionally, the increased CHEP amplitudes might be related to fear-induced alterations of nociceptive processing.
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Affiliation(s)
- Florin Allmendinger
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Paulina Simonne Scheuren
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- Department of Neurology, University Hospital Bern, Inselspital, University of Bern, Bern, Switzerland
- International Collaboration on Repair Discoveries, Vancouver, BC, Canada
- Department of Anesthesiology, Pharmacology & Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Iara De Schoenmacker
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Florian Brunner
- Department of Physical Medicine and Rheumatology, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Jan Rosner
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- Department of Neurology, University Hospital Bern, Inselspital, University of Bern, Bern, Switzerland
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Armin Curt
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Michèle Hubli
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
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Guiloff RJ, Campero M, Barraza GR, Treede RD, Matamala JM, Castillo JL. Pain-Related Vertex Evoked Potentials. Comparison of Surface Electrical to Heat Stimulation. J Clin Neurophysiol 2023; 40:616-624. [PMID: 37931163 DOI: 10.1097/wnp.0000000000000929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
INTRODUCTION Demonstration of nociceptive fiber abnormality is important for diagnosing neuropathic pain and small fiber neuropathies. This is usually assessed by brief heat pulses using lasers, contact heat, or special electrodes. We hypothesized that pain-related evoked potentials to conventional surface electrical stimulation (PREPse) can index Aδ afferences despite tactile Aß fibers coactivation. PREPse may be more readily used clinically than contact heat evoked potentials (CHEPS). METHODS Twenty-eight healthy subjects. Vertex (Cz-A1/A2) recordings. Electrical stimulation of middle finger and second toe with conventional ring, and forearm/leg skin with cup, electrodes. Contact heat stimulation to forearm and leg. Compression ischemic nerve blockade. RESULTS PREPse peripheral velocities were within the midrange of Aδ fibers. N1-P1 amplitude increased with pain numerical rating scale graded (0-10) electrical stimulation (n = 25) and decreased with increasing stimulation frequency. Amplitudes were unchanged by different presentation orders of four stimulation intensities. PREPse N1 (∼130 milliseconds) and N2 (∼345 milliseconds) peaks were approximately 40 milliseconds earlier than that with CHEPS. PREPse and CHEPS N1-N2 interpeak latency (∼207 milliseconds) were similar. PREPse became unrecordable with nerve blockade of Aδ fibers. CONCLUSIONS PREPse earlier N1 and N2 peaks, and similar interpeak N1-N2 latencies and central conduction velocities, or synaptic delays, to CHEPS are consistent with direct stimulation of Aδ fibers. The relation of vertex PREPse amplitude and pain, or the differential effects of frequency stimulation, is similar to pain-related evoked potential to laser, special electrodes, or contact heat stimulation. The relationship to Aδ was validated by conduction velocity and nerve block. Clinical utility of PREPse compared with CHEPS needs validation in somatosensory pathways lesions.
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Affiliation(s)
- Roberto J Guiloff
- Faculty of Medicine University of Chile, Santiago, Chile
- Imperial College, London, United Kingdom
- Neuromuscular Unit, Department of Neurology and Neurosurgery, Hospital Clinico Universidad de Chile, Santiago, Chile
| | - Mario Campero
- Faculty of Medicine University of Chile, Santiago, Chile
- Neuromuscular Unit, Department of Neurology and Neurosurgery, Hospital Clinico Universidad de Chile, Santiago, Chile
| | - Gonzalo R Barraza
- Neuromuscular Unit, Department of Neurology and Neurosurgery, Hospital Clinico Universidad de Chile, Santiago, Chile
| | | | - Jose M Matamala
- Faculty of Medicine University of Chile, Santiago, Chile
- Department of Neurological Science, Hospital El Salvador, Santiago, Chile
| | - Jose L Castillo
- Department of Neurological Science, Hospital El Salvador, Santiago, Chile
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McDaniel AL, Dimitrov TN, Bruehl SP, Monroe TB, Failla MD, Cowan RL, Ryan C, Anderson AR. Psychophysics of Pain: A Methodological Introduction. Pain Manag Nurs 2023; 24:442-451. [PMID: 36948969 PMCID: PMC10440278 DOI: 10.1016/j.pmn.2023.02.006] [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: 06/28/2022] [Revised: 12/29/2022] [Accepted: 02/15/2023] [Indexed: 03/24/2023]
Abstract
For over 100 years, psychophysics ..÷ the scientific study between physical stimuli and sensation ... has been successfully employed in numerous scientific and healthcare disciplines, as an objective measure of sensory phenomena. This manuscript provides an overview of fundamental psychophysical concepts, emphasizing pain and research application..÷defining common terms, methods, and procedures.Psychophysics can provide systematic and objective measures of sensory perception that can be used by nursing scientists to explore complex, subjective phenomena..÷such as pain perception. While there needs to be improved standardization of terms and techniques, psychophysical approaches are diverse and may be tailored to address or augment current research paradigms. The interdisciplinary nature of psychophysics..÷like nursing..÷provides a unique lens for understanding how our perceptions are influenced by measurable sensations. While the quest to understand human perception is far from complete, nursing science has an opportunity to contribute to pain research by using the techniques and methods available through psychophysical procedures.
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Affiliation(s)
- Aaron L McDaniel
- From The Ohio State University College of Nursing, Columbus, Ohio.
| | | | - Stephen P Bruehl
- Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Todd B Monroe
- From The Ohio State University College of Nursing, Columbus, Ohio
| | | | - Ronald L Cowan
- Department of Psychiatry, The University of Tennessee Health Science Center, Memphis, Tennessee
| | - Claire Ryan
- Vanderbilt University Medical Center, Nashville, Tennessee
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Hilgart DR, Iversen MM, Peters AY, Zabriskie MS, Hoareau GL, Vapniarsky N, Clark GA, Shah LM, Rieke V. Non-invasive central nervous system assessment of a porcine model of neuropathic pain demonstrates increased latency of somatosensory-evoked potentials. J Neurosci Methods 2023; 396:109934. [PMID: 37524248 PMCID: PMC10530261 DOI: 10.1016/j.jneumeth.2023.109934] [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: 05/18/2023] [Revised: 07/01/2023] [Accepted: 07/28/2023] [Indexed: 08/02/2023]
Abstract
BACKGROUND The study of chronic pain and its treatments requires a robust animal model with objective and quantifiable metrics. Porcine neuropathic pain models have been assessed with peripheral pain recordings and behavioral responses, but thus far central nervous system electrophysiology has not been investigated. This work aimed to record non-invasive, somatosensory-evoked potentials (SEPs) via electroencephalography in order to quantitatively assess chronic neuropathic pain induced in a porcine model. NEW METHOD Peripheral neuritis trauma (PNT) was induced unilaterally in the common peroneal nerve of domestic farm pigs, with the contralateral leg serving as the control for each animal. SEPs were generated by stimulation of the peripheral nerves distal to the PNT and were recorded non-invasively using transcranial electroencephalography (EEG). The P30 wave of the SEP was analyzed for latency changes. RESULTS P30 SEPs were successfully recorded with non-invasive EEG. PNT resulted in significantly longer P30 SEP latencies (p < 0.01 [n = 8]) with a median latency increase of 14.3 [IQR 5.0 - 17.5] ms. Histological results confirmed perineural inflammatory response and nerve damage around the PNT nerves. COMPARISON WITH EXISTING METHOD(S) Control P30 SEPs were similar in latency and amplitude to those previously recorded invasively in healthy pigs. Non-invasive recordings have numerous advantages over invasive measures. CONCLUSIONS P30 SEP latency can serve as a quantifiable neurological measure that reflects central nervous system processing in a porcine model of chronic pain. Advancing the development of a porcine chronic pain model will facilitate the translation of experimental therapies into human clinical trials.
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Affiliation(s)
- David R Hilgart
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA
| | - Marta M Iversen
- Department of Physical Medicine and Rehabilitation, University of Utah, Salt Lake City, UT, USA
| | - Angela Y Peters
- Department of Neurology, University of Utah, Salt Lake City, UT, USA
| | - Matthew S Zabriskie
- Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, USA
| | - Guillaume L Hoareau
- Department of Emergency Medicine, University of Utah, Salt Lake City, UT, USA
| | - Natalia Vapniarsky
- Department of Pathology Microbiology and Immunology, University of California Davis, Davis, CA, USA
| | - Gregory A Clark
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA
| | - Lubdha M Shah
- Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, USA
| | - Viola Rieke
- Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, UT, USA.
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Chan ACY, Kumar S, Tan G, Wong HY, Ong JJY, Chandra B, Huang H, Sharma VK, Lai PS. Expanding the genetic causes of small-fiber neuropathy: SCN genes and beyond. Muscle Nerve 2023; 67:259-271. [PMID: 36448457 DOI: 10.1002/mus.27752] [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: 04/27/2022] [Revised: 10/31/2022] [Accepted: 11/06/2022] [Indexed: 12/05/2022]
Abstract
Small-fiber neuropathy (SFN) is a disorder that exclusively affects the small nerve fibers, sparing the large nerve fibers. Thinly myelinated Aδ-fibers and unmyelinated C-fibers are damaged, leading to development of neuropathic pain, thermal dysfunction, sensory symptoms, and autonomic disturbances. Although many SFNs are secondary and due to immunological causes or metabolic disturbances, the etiology is unknown in up to half of the patients. Over the years, this proportion of "idiopathic SFN" has decreased, as familial and genetic causes have been discovered, thus shifting a proportion of once "idiopathic" cases to the genetic category. After the discovery of SCN9A-gene variants in 2012, SCN10A and SCN11A variants have been found to be pathogenic in SFN. With improved accessibility of SFN diagnostic tools and genetic tests, many non-SCN variants and genetically inherited systemic diseases involving the small nerve fibers have also been described, but only scattered throughout the literature. There are 80 SCN variants described as causing SFN, 8 genes causing hereditary sensory autonomic neuropathies (HSAN) described with pure SFN, and at least 7 genes involved in genetically inherited systemic diseases associated with SFN. This systematic review aims to consolidate and provide an updated overview on the genetic variants of SFN to date---SCN genes and beyond. Awareness of these genetic causes of SFN is imperative for providing treatment directions, prognostication, and management of expectations for patients and their health-care providers.
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Affiliation(s)
- Amanda C Y Chan
- Division of Neurology, Department of Medicine, National University Hospital, Singapore, Singapore
- Yong Loo Ling School of Medicine, National University of Singapore, Singapore, Singapore
| | - Shivaram Kumar
- Yong Loo Ling School of Medicine, National University of Singapore, Singapore, Singapore
| | - Grace Tan
- Yong Loo Ling School of Medicine, National University of Singapore, Singapore, Singapore
| | - Hiu Yi Wong
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
- Hong Kong Center for Neurodegenerative Diseases, Hong Kong Science Park, Hong Kong, China
| | - Jonathan J Y Ong
- Division of Neurology, Department of Medicine, National University Hospital, Singapore, Singapore
- Yong Loo Ling School of Medicine, National University of Singapore, Singapore, Singapore
| | - Bharatendu Chandra
- Division of Neurology, Department of Medicine, National University Hospital, Singapore, Singapore
- Yong Loo Ling School of Medicine, National University of Singapore, Singapore, Singapore
- Division of Medical Genetics, University of Iowa, Iowa City, Iowa, USA
| | - Hua Huang
- Yong Loo Ling School of Medicine, National University of Singapore, Singapore, Singapore
| | - Vijay Kumar Sharma
- Division of Neurology, Department of Medicine, National University Hospital, Singapore, Singapore
- Yong Loo Ling School of Medicine, National University of Singapore, Singapore, Singapore
| | - Poh San Lai
- Yong Loo Ling School of Medicine, National University of Singapore, Singapore, Singapore
- Adjunct Faculty, Genome Institute of Singapore, Singapore, Singapore
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Gamma-band oscillations of pain and nociception: A systematic review and meta-analysis of human and rodent studies. Neurosci Biobehav Rev 2023; 146:105062. [PMID: 36682424 DOI: 10.1016/j.neubiorev.2023.105062] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 01/08/2023] [Accepted: 01/18/2023] [Indexed: 01/22/2023]
Abstract
Pain-induced gamma-band oscillations (GBOs) are one of the most promising biomarkers of the pain experience. Although GBOs reliably encode pain perception across different individuals and species, considerable heterogeneity could be observed in the characteristics and functions of GBOs. However, such heterogeneity of GBOs and its underlying sources have rarely been detailed previously. Here, we conducted a systematic review and meta-analysis to characterize the temporal, frequential, and spatial characteristics of GBOs and summarize the functional significance of distinct GBOs. We found that GBO heterogeneity was mainly related to pain types, with a higher frequency (∼66 Hz) GBOs at the sensorimotor cortex elicited by phasic pain and a lower frequency (∼55 Hz) GBOs at the prefrontal cortex associated with tonic and chronic pains. Positive correlations between GBO magnitudes and pain intensity were observed in healthy participants. Notably, the characteristics and functions of GBOs seemed to be phylogenetically conserved across humans and rodents. Altogether, we provided a comprehensive description of heterogeneous GBOs in pain and nociception, laying the foundation for clinical applications of GBOs.
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High-speed heating of the skin using a contact thermode elicits brain responses comparable to CO 2 laser-evoked potentials. Clin Neurophysiol 2023; 146:1-9. [PMID: 36473333 DOI: 10.1016/j.clinph.2022.11.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 11/05/2022] [Accepted: 11/12/2022] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To compare nociceptive event-related brain potentials elicited by a high-speed contact-thermode vs an infrared CO2 laser stimulator. METHODS Contact heat-evoked potentials (CHEPs) and CO2 laser-evoked potentials (LEPs) were recorded in healthy volunteers using a high-speed contact-thermode (>200 °C/s) and a temperature-controlled CO2 laser. In separate experiments, stimuli were matched in terms of target surface temperature (55 °C) and intensity of perception. A finite-element model of skin heat transfer was used to explain observed differences. RESULTS For 55 °C stimuli, CHEPs were reduced in amplitude and delayed in latency as compared to LEPs. For perceptually matched stimuli (CHEPs: 62 °C; LEPs: 55 °C), amplitudes were similar, but CHEPs latencies remained delayed. These differences could be explained by skin thermal inertia producing differences in the heating profile of contact vs radiant heat at the dermo-epidermal junction. CONCLUSIONS Provided that steep heating ramps are used, and that target temperature is matched at the dermo-epidermal junction, contact and radiant laser heat stimulation elicit responses of similar magnitude. CHEPs are delayed compared to LEPs. SIGNIFICANCE CHEPs could be used as an alternative to LEPs for the diagnosis of neuropathic pain. Dedicated normative values must be used to account for differences in skin thermal transfer.
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Corneal Sub-Basal Nerve Plexus in Non-Diabetic Small Fiber Polyneuropathies and the Diagnostic Role of In Vivo Corneal Confocal Microscopy. J Clin Med 2023; 12:jcm12020664. [PMID: 36675593 PMCID: PMC9862881 DOI: 10.3390/jcm12020664] [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: 11/19/2022] [Revised: 12/24/2022] [Accepted: 01/07/2023] [Indexed: 01/18/2023] Open
Abstract
In vivo corneal confocal microscopy (IVCM) allows the immediate analysis of the corneal nerve quantity and morphology. This method became, an indispensable tool for the tropism examination, as it evaluates the small fiber plexus in the cornea. The IVCM provides us with direct information on the health of the sub-basal nerve plexus and indirectly on the peripheral nerve status. It is an important tool used to investigate peripheral polyneuropathies. Small-fiber neuropathy (SFN) is a group of neurological disorders characterized by neuropathic pain symptoms and autonomic complaints due to the selective involvement of thinly myelinated Aδ-fibers and unmyelinated C-fibers. Accurate diagnosis of SFN is important as it provides a basis for etiological work-up and treatment decisions. The diagnosis of SFN is sometimes challenging as the clinical picture can be difficult to interpret and standard electromyography is normal. In cases of suspected SFN, measurement of intraepidermal nerve fiber density through a skin biopsy and/or analysis of quantitative sensory testing can enable diagnosis. The purpose of the present review is to summarize the current knowledge about corneal nerves in different SFN. Specifically, we explore the correlation between nerve density and morphology and type of SFN, disease duration, and follow-up. We will discuss the relationship between cataracts and refractive surgery and iatrogenic dry eye disease. Furthermore, these new paradigms in SFN present an opportunity for neurologists and clinical specialists in the diagnosis and monitoring the peripheral small fiber polyneuropathies.
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Franz S, Heutehaus L, Tappe-Theodor A, Weidner N, Treede RD, Schuh-Hofer S. Noxious radiant heat evokes bi-component nociceptive withdrawal reflexes in spinal cord injured humans-A clinical tool to study neuroplastic changes of spinal neural circuits. Front Hum Neurosci 2023; 17:1141690. [PMID: 37200949 PMCID: PMC10185789 DOI: 10.3389/fnhum.2023.1141690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 04/04/2023] [Indexed: 05/20/2023] Open
Abstract
Investigating nocifensive withdrawal reflexes as potential surrogate marker for the spinal excitation level may widen the understanding of maladaptive nociceptive processing after spinal cord injury (SCI). The aim of this prospective, explorative cross-sectional observational study was to investigate the response behavior of individuals with SCI to noxious radiant heat (laser) stimuli and to assess its relation to spasticity and neuropathic pain, two clinical consequences of spinal hyperexcitability/spinal disinhibition. Laser stimuli were applied at the sole and dorsum of the foot and below the fibula head. Corresponding reflexes were electromyography (EMG) recorded ipsilateral. Motor responses to laser stimuli were analyzed and related to clinical readouts (severity of injury/spasticity/pain), using established clinical assessment tools. Twenty-seven participants, 15 with SCI (age 18-63; 6.5 years post-injury; AIS-A through D) and 12 non-disabled controls, [non-disabled controls (NDC); age 19-63] were included. The percentage of individuals with SCI responding to stimuli (70-77%; p < 0.001), their response rates (16-21%; p < 0.05) and their reflex magnitude (p < 0.05) were significantly higher compared to NDC. SCI-related reflexes clustered in two time-windows, indicating involvement of both A-delta- and C-fibers. Spasticity was associated with facilitated reflexes in SCI (Kendall-tau-b p ≤ 0.05) and inversely associated with the occurrence/severity of neuropathic pain (Fisher's exact p < 0.05; Eta-coefficient p < 0.05). However, neuropathic pain was not related to reflex behavior. Altogether, we found a bi-component motor hyperresponsiveness of SCI to noxious heat, which correlated with spasticity, but not neuropathic pain. Laser-evoked withdrawal reflexes may become a suitable outcome parameter to explore maladaptive spinal circuitries in SCI and to assess the effect of targeted treatment strategies. Registration: https://drks.de/search/de/trial/DRKS00006779.
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Affiliation(s)
- Steffen Franz
- Spinal Cord Injury Center, Heidelberg University Hospital, Heidelberg, Germany
- Steffen Franz,
| | - Laura Heutehaus
- Spinal Cord Injury Center, Heidelberg University Hospital, Heidelberg, Germany
| | - Anke Tappe-Theodor
- Department of Molecular Pharmacology, Medical Faculty Heidelberg, Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
| | - Norbert Weidner
- Spinal Cord Injury Center, Heidelberg University Hospital, Heidelberg, Germany
| | - Rolf-Detlef Treede
- Department of Neurophysiology, Mannheim Center for Translational Neuroscience, Medical Faculty Mannheim, Ruprecht-Karls-University of Heidelberg, Mannheim, Germany
| | - Sigrid Schuh-Hofer
- Department of Neurophysiology, Mannheim Center for Translational Neuroscience, Medical Faculty Mannheim, Ruprecht-Karls-University of Heidelberg, Mannheim, Germany
- Department of Neurology and Epileptology, University of Tübingen, Tübingen, Germany
- *Correspondence: Sigrid Schuh-Hofer,
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Bonin EAC, Lejeune N, Szymkowicz E, Bonhomme V, Martial C, Gosseries O, Laureys S, Thibaut A. Assessment and management of pain/nociception in patients with disorders of consciousness or locked-in syndrome: A narrative review. Front Syst Neurosci 2023; 17:1112206. [PMID: 37021037 PMCID: PMC10067681 DOI: 10.3389/fnsys.2023.1112206] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 03/06/2023] [Indexed: 04/07/2023] Open
Abstract
The assessment and management of pain and nociception is very challenging in patients unable to communicate functionally such as patients with disorders of consciousness (DoC) or in locked-in syndrome (LIS). In a clinical setting, the detection of signs of pain and nociception by the medical staff is therefore essential for the wellbeing and management of these patients. However, there is still a lot unknown and a lack of clear guidelines regarding the assessment, management and treatment of pain and nociception in these populations. The purpose of this narrative review is to examine the current knowledge regarding this issue by covering different topics such as: the neurophysiology of pain and nociception (in healthy subjects and patients), the source and impact of nociception and pain in DoC and LIS and, finally, the assessment and treatment of pain and nociception in these populations. In this review we will also give possible research directions that could help to improve the management of this specific population of severely brain damaged patients.
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Affiliation(s)
- Estelle A. C. Bonin
- Coma Science Group, GIGA-Consciousness Thematic Unit, GIGA-Research, Liège, Belgium
- Centre du Cerveau, Liège University Hospital, Liège, Belgium
| | - Nicolas Lejeune
- Coma Science Group, GIGA-Consciousness Thematic Unit, GIGA-Research, Liège, Belgium
- Centre Hospitalier Neurologique (CHN) William Lennox, Saint-Luc Hospital Group, Ottignies-Louvain-la-Neuve, Belgium
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Emilie Szymkowicz
- Coma Science Group, GIGA-Consciousness Thematic Unit, GIGA-Research, Liège, Belgium
- Centre du Cerveau, Liège University Hospital, Liège, Belgium
| | - Vincent Bonhomme
- Department of Anesthesia and Intensive Care Medicine, Liège University Hospital, Liège, Belgium
- Anesthesia and Perioperative Neuroscience Laboratory, GIGA-Consciousness Thematic Unit, GIGA-Research, Liège, Belgium
| | - Charlotte Martial
- Coma Science Group, GIGA-Consciousness Thematic Unit, GIGA-Research, Liège, Belgium
- Centre du Cerveau, Liège University Hospital, Liège, Belgium
| | - Olivia Gosseries
- Coma Science Group, GIGA-Consciousness Thematic Unit, GIGA-Research, Liège, Belgium
- Centre du Cerveau, Liège University Hospital, Liège, Belgium
| | - Steven Laureys
- Coma Science Group, GIGA-Consciousness Thematic Unit, GIGA-Research, Liège, Belgium
- Centre du Cerveau, Liège University Hospital, Liège, Belgium
- Joint International Research Unit on Consciousness, CERVO Brain Research Centre, Centre Intégré Universitaire de Santé et Services Sociaux (CIUSS), University Laval, Québec City, QC, Canada
| | - Aurore Thibaut
- Coma Science Group, GIGA-Consciousness Thematic Unit, GIGA-Research, Liège, Belgium
- Centre du Cerveau, Liège University Hospital, Liège, Belgium
- *Correspondence: Aurore Thibaut,
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Barjola P, Peláez I, Ferrera D, González-Gutiérrez JL, Velasco L, Peñacoba-Puente C, López-López A, Fernandes-Magalhaes R, Mercado F. Electrophysiological indices of pain expectation abnormalities in fibromyalgia patients. Front Hum Neurosci 2022; 16:943976. [PMID: 36248693 PMCID: PMC9562711 DOI: 10.3389/fnhum.2022.943976] [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: 05/14/2022] [Accepted: 09/12/2022] [Indexed: 11/13/2022] Open
Abstract
Fibromyalgia is a chronic pain syndrome characterized by dysfunctional processing of nociceptive stimulation. Neuroimaging studies have pointed out that pain-related network functioning seems to be altered in these patients. It is thought that this clinical symptomatology may be maintained or even strengthened because of an enhanced expectancy for painful stimuli or its forthcoming appearance. However, neural electrophysiological correlates associated with such attentional mechanisms have been scarcely explored. In the current study, expectancy processes of upcoming laser stimulation (painful and non-painful) and its further processing were explored by event-related potentials (ERPs). Nineteen fibromyalgia patients and twenty healthy control volunteers took part in the experiment. Behavioral measures (reaction times and subjective pain perception) were also collected. We manipulated the pain/no pain expectancy through an S1–S2 paradigm (cue-target). S1 (image: triangle or square) predicted the S2 appearance (laser stimulation: warmth or pinprick sensation). Laser stimuli were delivered using a CO2 laser device. Temporal and spatial principal component analyses were employed to define and quantify the ERP component reliability. Statistical analyses revealed the existence of an abnormal pattern of pain expectancy in patients with fibromyalgia. Specifically, our results showed attenuated amplitudes at posterior lCNV component in anticipation of painful stimulation that was not found in healthy participants. In contrast, although larger P2 amplitudes to painful compared to innocuous events were shown, patients did not show any amplitude change in this laser-evoked response as a function of pain predictive cues (as occurred in the healthy control group). Additionally, analyses of the subjective perception of pain and reaction time indicated that laser stimuli preceded by pain cues were rated as more painful than those signaling non-pain expectancy and were associated with faster responses. Differences between groups were not found. The present findings suggest the presence of dysfunction in pain expectation mechanisms in fibromyalgia that eventually may make it difficult for patients to correctly interpret signs that prevent pain symptoms. Furthermore, the abnormal pattern in pain expectancy displayed by fibromyalgia patients could result in ineffective pain coping strategies. Understanding the neural correlates of pain processing and its modulatory factors is crucial to identify treatments for chronic pain syndromes.
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Just Breathe: Improving LEP Outcomes through Long Interval Breathing. CLINICAL AND TRANSLATIONAL NEUROSCIENCE 2022. [DOI: 10.3390/ctn6020013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background: Laser-evoked potentials (LEPs) constitute an objective clinical diagnostic method used to investigate the functioning of the nociceptor system, including signaling in thin peripheral nerve fibers: Aδ and C fibers. There is preliminary evidence that phase locking LEPs with the breathing cycle can improve the parameters used to evaluate LEPs. Methods: We tested a simple breathing protocol as a low-cost improvement to LEP testing of the hands. Twenty healthy participants all underwent three variants of LEP protocols: following a video-guided twelve-second breathing instruction, watching a nature video, or using the classic LEP method of focusing on the hand being stimulated. Results: The breath protocol produced significantly shorter latencies as compared with the nature or classic protocol. It was also the least prone to artifacts and was deemed most acceptable by the subjects. There was no difference between the protocols regarding LEP amplitudes. Conclusions: Using a breathing video can be a simple, low-cost improvement for LEP testing in research and clinical diagnostics.
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Wang H, Guo Y, Tu Y, Peng W, Lu X, Bi Y, Iannetti GD, Hu L. Neural processes responsible for the translation of sustained nociceptive inputs into subjective pain experience. Cereb Cortex 2022; 33:634-650. [PMID: 35244170 PMCID: PMC9890464 DOI: 10.1093/cercor/bhac090] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 01/24/2022] [Accepted: 02/11/2022] [Indexed: 02/04/2023] Open
Abstract
Tracking and predicting the temporal structure of nociceptive inputs is crucial to promote survival, as proper and immediate reactions are necessary to avoid actual or potential bodily injury. Neural activities elicited by nociceptive stimuli with different temporal structures have been described, but the neural processes responsible for translating nociception into pain perception are not fully elucidated. To tap into this issue, we recorded electroencephalographic signals from 48 healthy participants receiving thermo-nociceptive stimuli with 3 different durations and 2 different intensities. We observed that pain perception and several brain responses are modulated by stimulus duration and intensity. Crucially, we identified 2 sustained brain responses that were related to the emergence of painful percepts: a low-frequency component (LFC, < 1 Hz) originated from the insula and anterior cingulate cortex, and an alpha-band event-related desynchronization (α-ERD, 8-13 Hz) generated from the sensorimotor cortex. These 2 sustained brain responses were highly coupled, with the α-oscillation amplitude that fluctuated with the LFC phase. Furthermore, the translation of stimulus duration into pain perception was serially mediated by α-ERD and LFC. The present study reveals how brain responses elicited by nociceptive stimulation reflect the complex processes occurring during the translation of nociceptive information into pain perception.
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Affiliation(s)
- Hailu Wang
- CAS Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, China,Department of Psychology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yifei Guo
- Neuroscience and Behaviour Laboratory, Istituto Italiano di Tecnologia, Rome 30 16163, Italy,Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom
| | - Yiheng Tu
- CAS Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, China,Department of Psychology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Weiwei Peng
- Brain Function and Psychological Science Research Center, Shenzhen University, Shenzhen 518061, China
| | - Xuejing Lu
- CAS Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, China,Department of Psychology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yanzhi Bi
- CAS Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, China,Department of Psychology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Gian Domenico Iannetti
- Neuroscience and Behaviour Laboratory, Istituto Italiano di Tecnologia, Rome 30 16163, Italy,Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom
| | - Li Hu
- Corresponding author: CAS Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, China.
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Abstract
Diabetes polyneuropathy is an important complication of diabetes polyneuropathy, and its notable sequelae of foot ulceration, autonomic dysfunction, and neuropathic pain are associated with significant morbidity and mortality. Despite the major impact on quality of life and health economic costs, it remains underdiagnosed until late in its natural history, and there is lack of any intervention that can reverse its clinical progress. Assessment of small fiber neuropathy (SFN) in diabetes offers an opportunity to detect abnormalities at an early stage so that both interventional studies and preventative measures can be enacted to prevent progression to the devastating complications of foot ulceration and cardiac dysautonomic death. Over the last two decades, significant advances have been made in understanding the pathophysiology of diabetes neuropathy and its assessment. In this review, we discuss limitations of the screening methods recommended in current clinical guidelines which are based on large nerve fiber assessments. Thereafter, we discuss in detail the various methods currently available to assess small fiber structure and function and examine their individual strength and limitations. Finally, we discuss the reasons why despite the considerable body of evidence available, legislators and global experts have yet to incorporate the assessment of SFN as routine clinical surveillance in diabetes management. We hope that these insights will stimulate further discussion and be instrumental in the early adoption of these methods so as to reduce the burden of complications arising due to diabetes polyneuropathy.
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Affiliation(s)
- Sanjeev Sharma
- Diabetes Trails unit, Ipswich Hospital
(ESNEFT), Ipswich, UK
| | - Prashanth Vas
- Department of Diabetes, Kings College
Hospital, London, UK
| | - Gerry Rayman
- Diabetes Trails unit, Ipswich Hospital
(ESNEFT), Ipswich, UK
- Gerry Rayman, MD, Diabetes Trials Unit,
Department of Diabetes & Endocrinology, Ipswich Hospital, ESNEFT, Heath
Road, Ipswich, Suffolk IP4 5RH, UK.
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16
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Alfaro-Rodriguez A, Cortes-Altamirano J, Reyes-Long S, Bandala C, Morraz-Varela A, Bonilla-Jaime H. Neuropathic Pain in Parkinson's Disease. Neurol India 2022; 70:1879-1886. [DOI: 10.4103/0028-3886.359257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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17
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Verdugo RJ, Matamala JM, Inui K, Kakigi R, Valls-Solé J, Hansson P, Bernhard Nilsen K, Lombardi R, Lauria G, Petropoulos IN, Malik RA, Treede RD, Baumgärtner U, Jara PA, Campero M. Review of techniques useful for the assessment of sensory small fiber neuropathies: Report from an IFCN expert group. Clin Neurophysiol 2022; 136:13-38. [DOI: 10.1016/j.clinph.2022.01.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 01/04/2022] [Accepted: 01/06/2022] [Indexed: 02/09/2023]
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18
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Morgalla MH, Zhang Y, de Barros Filho MF, Lepski G, Chander BS. Laser-evoked potentials recover gradually when using dorsal root ganglion stimulation, and this influences nociceptive pathways in neuropathic pain patients. Pain Pract 2021; 22:372-380. [PMID: 34787959 DOI: 10.1111/papr.13094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 10/06/2021] [Accepted: 11/08/2021] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Dorsal root ganglion stimulation (DRGS) is able to relieve chronic neuropathic pain. There seems evidence that DRGS might achieve this by gradually influencing pain pathways. We used laser-evoked potentials (LEP) to verify our hypothesis that the recovery of the LEP may reflect DRGS-induced changes within the nociceptive system. METHODS Nine patients (mean age 56.8 years, range 36-77 years, two females) diagnosed with chronic neuropathic pain in the knee or groin were enrolled in the study. We measured each patient's LEP at the painful limb and contralateral control limb on the first, fourth, and seventh day after implantation of the DRGS system. We used the numeric rating scale (NRS) for the simultaneous pain assessment. RESULTS The LEP amplitude of the N2-P2 complex showed a significant increase on day 7 when compared to day 1 (Z = -2.666, p = 0.008) and to day 4 (Z = -2.547, p = 0.011), respectively. There was no significant difference in the N2-P2 complex amplitude between ON and OFF states during DRGS. The patients' NRS significantly decreased after 1 day (p = 0.007), 4 days (p = 0.007), and 7 days (p = 0.007) when compared to the baseline. CONCLUSIONS The results show that with DRGS, the LEP recovered gradually within 7 days in neuropathic pain patients. Therefore, reduction of the NRS in patients with chronic neuropathic pain might be due to DRGS-induced processes within the nociceptive system. These processes might indicate neuroplasticity mediated recovery of the LEP.
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Affiliation(s)
| | - Yi Zhang
- Department of Neurosurgery, Eberhard-Karls University, Tübingen, Germany
| | | | - Guilherme Lepski
- Department of Neurosurgery, Eberhard-Karls University, Tübingen, Germany.,Department of Psychiatry, School of Medicine, University of São Paulo, São Paulo, Brazil
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Fabig SC, Kersebaum D, Lassen J, Sendel M, Jendral S, Muntean A, Baron R, Hüllemann P. A modality-specific somatosensory evoked potential test protocol for clinical evaluation: A feasibility study. Clin Neurophysiol 2021; 132:3104-3115. [PMID: 34740042 DOI: 10.1016/j.clinph.2021.08.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 07/26/2021] [Accepted: 08/29/2021] [Indexed: 10/20/2022]
Abstract
OBJECTIVE We aimed to establish an objective neurophysiological test protocol that can be used to assess the somatosensory nervous system. METHODS In order to assess most fiber subtypes of the somatosensory nervous system, repetitive stimuli of seven different modalities (touch, vibration, pinprick, cold, contact heat, laser, and warmth) were synchronized with the electroencephalogram (EEG) and applied on the cheek and dorsum of the hand and dorsum of the foot in 21 healthy subjects and three polyneuropathy (PNP) patients. Latencies and amplitudes of the modalities were assessed and compared. Patients received quantitative sensory testing (QST) as reference. RESULTS We found reproducible evoked potentials recordings for touch, vibration, pinprick, contact-heat, and laser stimuli. The recording of warm-evoked potentials was challenging in young healthy subjects and not applicable in patients. Latencies were shortest within Aβ-fiber-mediated signals and longest within C-fibers. The test protocol detected function loss within the Aβ-fiber and Aδ-fiber-range in PNP patients. This function loss corresponded with QST findings. CONCLUSION In this pilot study, we developed a neurophysiological test protocol that can specifically assess most of the somatosensory modalities. Despite technical challenges, initial patient data appear promising regarding a possible future clinical application. SIGNIFICANCE Established and custom-made stimulators were combined to assess different fiber subtypes of the somatosensory nervous system using modality-specific evoked potentials.
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Affiliation(s)
- Sophie-Charlotte Fabig
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Arnold-Heller-Straße 3, Haus D, 24105 Kiel, Germany.
| | - Dilara Kersebaum
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Arnold-Heller-Straße 3, Haus D, 24105 Kiel, Germany
| | - Josephine Lassen
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Arnold-Heller-Straße 3, Haus D, 24105 Kiel, Germany
| | - Manon Sendel
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Arnold-Heller-Straße 3, Haus D, 24105 Kiel, Germany
| | - Swantje Jendral
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Arnold-Heller-Straße 3, Haus D, 24105 Kiel, Germany
| | - Alexandra Muntean
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Arnold-Heller-Straße 3, Haus D, 24105 Kiel, Germany
| | - Ralf Baron
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Arnold-Heller-Straße 3, Haus D, 24105 Kiel, Germany
| | - Philipp Hüllemann
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Arnold-Heller-Straße 3, Haus D, 24105 Kiel, Germany
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20
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Scheuren PS, David G, Kramer JLK, Jutzeler CR, Hupp M, Freund P, Curt A, Hubli M, Rosner J. Combined Neurophysiologic and Neuroimaging Approach to Reveal the Structure-Function Paradox in Cervical Myelopathy. Neurology 2021; 97:e1512-e1522. [PMID: 34380751 DOI: 10.1212/wnl.0000000000012643] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 07/16/2021] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND AND OBJECTIVES To explore the so-called structure-function paradox in individuals with focal spinal lesions by means of tract-specific MRI coupled with multimodal evoked potentials and quantitative sensory testing. METHODS Individuals with signs and symptoms attributable to cervical myelopathy (i.e., no evidence of competing neurologic diagnoses) were recruited at the Balgrist University Hospital, Zurich, Switzerland, between February 2018 and March 2019. We evaluated the relationship between the extent of structural damage within spinal nociceptive pathways (i.e., dorsal horn, spinothalamic tract, anterior commissure) assessed with atlas-based MRI and (1) the functional integrity of spinal nociceptive pathways measured with contact heat-, cold-, and pinprick-evoked potentials and (2) clinical somatosensory phenotypes assessed with quantitative sensory testing. RESULTS Sixteen individuals (mean age 61 years) with either degenerative (n = 13) or posttraumatic (n = 3) cervical myelopathy participated in the study. Most individuals presented with mild myelopathy (modified Japanese Orthopaedic Association score >15; n = 13). A total of 71% of individuals presented with structural damage within spinal nociceptive pathways on MRI. However, 50% of these individuals presented with complete functional sparing (i.e., normal contact heat-, cold-, and pinprick-evoked potentials). The extent of structural damage within spinal nociceptive pathways was not associated with functional integrity of thermal (heat: p = 0.57; cold: p = 0.49) and mechano-nociceptive pathways (p = 0.83) or with the clinical somatosensory phenotype (heat: p = 0.16; cold: p = 0.37; mechanical: p = 0.73). The amount of structural damage to the spinothalamic tract did not correlate with spinothalamic conduction velocity (p > 0.05; ρ = -0.11). DISCUSSION Our findings provide neurophysiologic evidence to substantiate that structural damage in the spinal cord does not equate to functional somatosensory deficits. This study recognizes the pronounced structure-function paradox in cervical myelopathies and underlines the inevitable need for a multimodal phenotyping approach to reveal the eloquence of lesions within somatosensory pathways.
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Affiliation(s)
- Paulina Simonne Scheuren
- From the Spinal Cord Injury Center (P.S.S., G.D., M. Hupp, P.F., A.C., M. Hubli, J.R.), Balgrist University Hospital, University of Zurich, Switzerland; International Collaboration on Repair Discoveries (ICORD) (J.L.K.K.), Department of Anesthesiology, Pharmacology, and Therapeutics, Faculty of Medicine (J.L.K.K.), University of British Columbia, Vancouver, Canada; Department of Biosystems Science and Technology (C.R.J.), Swiss Federal Institute of Technology Zurich, Switzerland; Wellcome Centre for Human Neuroimaging (P.F.), UCL Institute of Neurology, UCL, London, UK; Department of Neurophysics (P.F.), Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; and Department of Neurology (J.R.), University Hospital Bern, Inselspital, University of Bern, Switzerland
| | - Gergely David
- From the Spinal Cord Injury Center (P.S.S., G.D., M. Hupp, P.F., A.C., M. Hubli, J.R.), Balgrist University Hospital, University of Zurich, Switzerland; International Collaboration on Repair Discoveries (ICORD) (J.L.K.K.), Department of Anesthesiology, Pharmacology, and Therapeutics, Faculty of Medicine (J.L.K.K.), University of British Columbia, Vancouver, Canada; Department of Biosystems Science and Technology (C.R.J.), Swiss Federal Institute of Technology Zurich, Switzerland; Wellcome Centre for Human Neuroimaging (P.F.), UCL Institute of Neurology, UCL, London, UK; Department of Neurophysics (P.F.), Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; and Department of Neurology (J.R.), University Hospital Bern, Inselspital, University of Bern, Switzerland
| | - John Lawrence Kipling Kramer
- From the Spinal Cord Injury Center (P.S.S., G.D., M. Hupp, P.F., A.C., M. Hubli, J.R.), Balgrist University Hospital, University of Zurich, Switzerland; International Collaboration on Repair Discoveries (ICORD) (J.L.K.K.), Department of Anesthesiology, Pharmacology, and Therapeutics, Faculty of Medicine (J.L.K.K.), University of British Columbia, Vancouver, Canada; Department of Biosystems Science and Technology (C.R.J.), Swiss Federal Institute of Technology Zurich, Switzerland; Wellcome Centre for Human Neuroimaging (P.F.), UCL Institute of Neurology, UCL, London, UK; Department of Neurophysics (P.F.), Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; and Department of Neurology (J.R.), University Hospital Bern, Inselspital, University of Bern, Switzerland
| | - Catherine Ruth Jutzeler
- From the Spinal Cord Injury Center (P.S.S., G.D., M. Hupp, P.F., A.C., M. Hubli, J.R.), Balgrist University Hospital, University of Zurich, Switzerland; International Collaboration on Repair Discoveries (ICORD) (J.L.K.K.), Department of Anesthesiology, Pharmacology, and Therapeutics, Faculty of Medicine (J.L.K.K.), University of British Columbia, Vancouver, Canada; Department of Biosystems Science and Technology (C.R.J.), Swiss Federal Institute of Technology Zurich, Switzerland; Wellcome Centre for Human Neuroimaging (P.F.), UCL Institute of Neurology, UCL, London, UK; Department of Neurophysics (P.F.), Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; and Department of Neurology (J.R.), University Hospital Bern, Inselspital, University of Bern, Switzerland
| | - Markus Hupp
- From the Spinal Cord Injury Center (P.S.S., G.D., M. Hupp, P.F., A.C., M. Hubli, J.R.), Balgrist University Hospital, University of Zurich, Switzerland; International Collaboration on Repair Discoveries (ICORD) (J.L.K.K.), Department of Anesthesiology, Pharmacology, and Therapeutics, Faculty of Medicine (J.L.K.K.), University of British Columbia, Vancouver, Canada; Department of Biosystems Science and Technology (C.R.J.), Swiss Federal Institute of Technology Zurich, Switzerland; Wellcome Centre for Human Neuroimaging (P.F.), UCL Institute of Neurology, UCL, London, UK; Department of Neurophysics (P.F.), Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; and Department of Neurology (J.R.), University Hospital Bern, Inselspital, University of Bern, Switzerland
| | - Patrick Freund
- From the Spinal Cord Injury Center (P.S.S., G.D., M. Hupp, P.F., A.C., M. Hubli, J.R.), Balgrist University Hospital, University of Zurich, Switzerland; International Collaboration on Repair Discoveries (ICORD) (J.L.K.K.), Department of Anesthesiology, Pharmacology, and Therapeutics, Faculty of Medicine (J.L.K.K.), University of British Columbia, Vancouver, Canada; Department of Biosystems Science and Technology (C.R.J.), Swiss Federal Institute of Technology Zurich, Switzerland; Wellcome Centre for Human Neuroimaging (P.F.), UCL Institute of Neurology, UCL, London, UK; Department of Neurophysics (P.F.), Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; and Department of Neurology (J.R.), University Hospital Bern, Inselspital, University of Bern, Switzerland
| | - Armin Curt
- From the Spinal Cord Injury Center (P.S.S., G.D., M. Hupp, P.F., A.C., M. Hubli, J.R.), Balgrist University Hospital, University of Zurich, Switzerland; International Collaboration on Repair Discoveries (ICORD) (J.L.K.K.), Department of Anesthesiology, Pharmacology, and Therapeutics, Faculty of Medicine (J.L.K.K.), University of British Columbia, Vancouver, Canada; Department of Biosystems Science and Technology (C.R.J.), Swiss Federal Institute of Technology Zurich, Switzerland; Wellcome Centre for Human Neuroimaging (P.F.), UCL Institute of Neurology, UCL, London, UK; Department of Neurophysics (P.F.), Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; and Department of Neurology (J.R.), University Hospital Bern, Inselspital, University of Bern, Switzerland
| | - Michèle Hubli
- From the Spinal Cord Injury Center (P.S.S., G.D., M. Hupp, P.F., A.C., M. Hubli, J.R.), Balgrist University Hospital, University of Zurich, Switzerland; International Collaboration on Repair Discoveries (ICORD) (J.L.K.K.), Department of Anesthesiology, Pharmacology, and Therapeutics, Faculty of Medicine (J.L.K.K.), University of British Columbia, Vancouver, Canada; Department of Biosystems Science and Technology (C.R.J.), Swiss Federal Institute of Technology Zurich, Switzerland; Wellcome Centre for Human Neuroimaging (P.F.), UCL Institute of Neurology, UCL, London, UK; Department of Neurophysics (P.F.), Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; and Department of Neurology (J.R.), University Hospital Bern, Inselspital, University of Bern, Switzerland
| | - Jan Rosner
- From the Spinal Cord Injury Center (P.S.S., G.D., M. Hupp, P.F., A.C., M. Hubli, J.R.), Balgrist University Hospital, University of Zurich, Switzerland; International Collaboration on Repair Discoveries (ICORD) (J.L.K.K.), Department of Anesthesiology, Pharmacology, and Therapeutics, Faculty of Medicine (J.L.K.K.), University of British Columbia, Vancouver, Canada; Department of Biosystems Science and Technology (C.R.J.), Swiss Federal Institute of Technology Zurich, Switzerland; Wellcome Centre for Human Neuroimaging (P.F.), UCL Institute of Neurology, UCL, London, UK; Department of Neurophysics (P.F.), Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; and Department of Neurology (J.R.), University Hospital Bern, Inselspital, University of Bern, Switzerland.
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Measuring Latency Variations in Evoked Potential Components Using a Simple Autocorrelation Technique. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2021; 2021:8875445. [PMID: 34603486 PMCID: PMC8481054 DOI: 10.1155/2021/8875445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 08/28/2021] [Indexed: 11/29/2022]
Abstract
Interpretation of averaged evoked potentials is difficult when the time relationship between stimulus and response is not constant. Later components are more prone to latency jitter, making them insufficiently reliable for routine clinical use even though they could contribute to greater understanding of the functioning of polysynaptic components of the afferent nervous system. This study is aimed at providing a simple but effective method of identifying and quantifying latency jitter in averaged evoked potentials. Autocorrelation techniques were applied within defined time windows on simulated jittered signals embedded within the noise component of recorded evoked potentials and on real examples of somatosensory evoked potentials. We demonstrated that the technique accurately identifies the distribution and maximum levels of jitter of the simulated components and clearly identifies the jitter properties of real evoked potential recording components. This method is designed to complement the conventional analytical methods used in neurophysiological practice to provide valuable additional information about the distribution of latency jitter within an averaged evoked potential. It will be useful for the assessment of the reliability of averaged components and will aid the interpretation of longer-latency, polysynaptic components such as those found in nociceptive evoked potentials.
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Ernst M, Ljutow A, Stockinger L, Stoyanov J, Landmann G. Variability in clinical and neurophysiological evaluation of pain development following acute spinal cord injury: a case report. Spinal Cord Ser Cases 2021; 7:72. [PMID: 34365469 DOI: 10.1038/s41394-021-00435-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 07/23/2021] [Accepted: 07/23/2021] [Indexed: 11/09/2022] Open
Abstract
INTRODUCTION Chronic neuropathic pain (NeP) often develops following traumatic spinal cord injury (SCI). This case report explores variability in clinical and neurophysiological aspects of pain evaluation in early post-trauma stages. CASE PRESENTATION A 34-year old female presenting with acute incomplete sensorimotor tetraplegia C4 AIS D was examined by neurological examination and pain assessment at three time points after acute trauma T1 (8 weeks), T2 (11 weeks), and T3 (24 weeks). Quantitative sensory testing (QST) and laser-evoked potentials (LEPs) were measured above (control area), at (area of NeP), and below (foot) the neurological level of injury (NLI). Musculo-skeletal and neuropathic pain were clinically present already during T1 but showed variations in localization and occurrence over time. Neuropathic pain classification varied between time points due to shifting of NLI. Above-level QST revealed minor, less pronounced abnormalities similar to at-level site. At-level QST (site of NeP) showed loss for thermal and mechanical detection thresholds but also gain of function for mechanical pain thresholds with a tendency of amelioration over time. QST below-level did not reveal remarkable changes over time. LEPs above- and below-level were within normal limits. At-level LEPs abolished after T1. DISCUSSION In early stages post injury (up to 6 month) variations in pain presentation for both, musculo-skeletal and neuropathic pain as well as QST and LEP could be demonstrated. These findings suggest ongoing adaption mechanisms in sensory pathways, which require further exploration and may be relevant for prognostic and preventive strategies against the development of chronic neuropathic and nociceptive pain.
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Affiliation(s)
- Mario Ernst
- Centre for Pain Medicine, Swiss Paraplegic Centre, Nottwil, Switzerland
| | - André Ljutow
- Centre for Pain Medicine, Swiss Paraplegic Centre, Nottwil, Switzerland
| | - Lenka Stockinger
- Centre for Pain Medicine, Swiss Paraplegic Centre, Nottwil, Switzerland
| | - Jivko Stoyanov
- Swiss Paraplegic Research, Swiss Paraplegic Centre, Nottwil, Switzerland.,Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
| | - Gunther Landmann
- Centre for Pain Medicine, Swiss Paraplegic Centre, Nottwil, Switzerland.
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Frasson E, Tozzi MC, Bordignon M, Motti L, Ferrari F, Torre G, Graziottin A, Monaco S, Bertolasi L. Laser-Evoked Potentials to Pudendal Stimulation in Healthy Subjects: A Pilot Study. J Clin Neurophysiol 2021; 38:317-322. [PMID: 32217884 DOI: 10.1097/wnp.0000000000000694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
PURPOSE Laser-evoked potentials (LEPs) are useful neurophysiological tools for investigating the A-delta sensory peripheral fibers and the central nociceptive pathway. The current investigation aims to obtain normative values of LEPs via pudendal nerve stimulation in healthy adult volunteers. METHODS Laser-evoked potentials were recorded in 16 men and 22 women, 22 to 75 years of age, using neodymium and yttrium and aluminum and perovskite laser bilateral stimulation to the pudendal nerve-supplied skin and the dorsal surface of the hands and feet. We assessed the perceptive threshold, latency, and amplitude of the N1 component and main vertex N2-P2 complex. The relationship between gender, age, height, and site of stimulation was statistically analyzed. RESULTS Both in men and in women, laser perceptive threshold increased from genitalia to foot and from hand to foot (P ≤ 0.001). N1 and N2-P2 latencies progressively increased from pudendal area to hand to foot (P ≤ 0.008). N1 and N2-P2 complex LEP amplitudes progressively decreased from hand to genitalia to foot (P ≤ 0.04). The latencies of N1 component and N2-P2 complex of LEPs correlated with body height, whereas the amplitude of the N2-P2 complex correlated negatively with age; no correlations were observed between the latencies and amplitudes with gender. CONCLUSIONS This study provides normative data on pudendal LEPs versus hand and foot LEPs. Incorporation of pudendal LEPs into clinical practice could provide a valuable neurophysiological tool for the study of pelvic pain syndromes.
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Affiliation(s)
- Emma Frasson
- Department of Neurology, AULSS 6 Euganea, Cittadella Hospital, Padua, Italy
| | - Maria Chiara Tozzi
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Clinical Neurology, University of Verona, Verona, Italy
| | - Monia Bordignon
- Department of Management Control, AULSS 6 Euganea, Cittadella Hospital, Padua, Italy
| | - Luisa Motti
- Department of Neurophysiology, Azienda Ospedaliera S. Maria Nuova, Reggio Emilia, Italy ; and
| | - Francesca Ferrari
- Department of Neurophysiology, Azienda Ospedaliera S. Maria Nuova, Reggio Emilia, Italy ; and
| | - Gabriella Torre
- Department of Neurophysiology, Azienda Ospedaliera S. Maria Nuova, Reggio Emilia, Italy ; and
| | - Alessandra Graziottin
- Gynaecology and Medical Sexology Centre, Hospitale San Raffaele Resnati, Milan, Italy
| | - Salvatore Monaco
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Clinical Neurology, University of Verona, Verona, Italy
| | - Laura Bertolasi
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Clinical Neurology, University of Verona, Verona, Italy
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24
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Kersebaum D, Fabig SC, Sendel M, Muntean AC, Baron R, Hüllemann P. Revealing the time course of laser-evoked potential habituation by high temporal resolution analysis. Eur J Pain 2021; 25:2112-2128. [PMID: 34155707 DOI: 10.1002/ejp.1823] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 06/10/2021] [Indexed: 11/12/2022]
Abstract
BACKGROUND AND OBJECTIVES Reduced laser-evoked potential (LEP) habituation indicates abnormal central pain processing. But the paradigm (four stimulation blocks a 25 stimuli) is time consuming and potentially omits important information on the exact habituation time course. This study examined whether a high temporal resolution (HTR) analysis (dividing the four stimulation blocks into 12 analysis blocks) can answer the following questions: (a) After how many stimuli does LEP habituation occur? (b) Is there a difference in LEP habituation in younger versus older subjects? (c) Is HTR applicable on radiculopathy patients? METHODS EEG data of 129 subjects were included. Thirty-four young healthy and 28 advanced-aged healthy subjects were tested with LEPs on the hand dorsum. Thirty-seven radiculopathy patients and 30 controls were tested with LEPs on the L3 dermatome. The EEG data of the hand dorsa have been analysed conventionally and with HTR analysis. The applicability of HTR has been tested on radiculopathy patients and respective controls. RESULTS HTR was well feasible in young healthy subjects and revealed a strong habituation effect during the first 25 stimuli (i.e. within the first 5 min). After approximately 48 stimuli, no further significant habituation was detectable. LEP amplitudes were higher in young subjects. HTR was unsuitable for elderly subjects and middle-aged radiculopathy patients. CONCLUSIONS In young healthy subjects, HTR allows a shortening of the test protocol while providing a detailed information on the time course of LEP habituation. A shorter protocol might be useful for the applicability of the LEP paradigm for clinical and experimental settings as well as pharmacological studies. SIGNIFICANCE The usage of high temporal resolution (HTR) analysis in young healthy subjects enables a short test protocol and provides the exact time course of laser-evoked potential habituation. This can be useful for the examination of neurological conditions affecting younger patients and for pharmacological studies. HTR was inapplicable in advanced-aged subjects and patients with radiculopathy.
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Affiliation(s)
- Dilara Kersebaum
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Clinic Schleswig-Holstein, Kiel, Germany
| | - Sophie-Charlotte Fabig
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Clinic Schleswig-Holstein, Kiel, Germany
| | - Manon Sendel
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Clinic Schleswig-Holstein, Kiel, Germany
| | - Alexandra Cristina Muntean
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Clinic Schleswig-Holstein, Kiel, Germany
| | - Ralf Baron
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Clinic Schleswig-Holstein, Kiel, Germany
| | - Philipp Hüllemann
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Clinic Schleswig-Holstein, Kiel, Germany
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25
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Mouraux A, Bloms-Funke P, Boesl I, Caspani O, Chapman SC, Di Stefano G, Finnerup NB, Garcia-Larrea L, Goetz M, Kostenko A, Pelz B, Pogatzki-Zahn E, Schubart K, Stouffs A, Truini A, Tracey I, Troconiz IF, Van Niel J, Vela JM, Vincent K, Vollert J, Wanigasekera V, Wittayer M, Phillips KG, Treede RD. IMI2-PainCare-BioPain-RCT3: a randomized, double-blind, placebo-controlled, crossover, multi-center trial in healthy subjects to investigate the effects of lacosamide, pregabalin, and tapentadol on biomarkers of pain processing observed by electroencephalography (EEG). Trials 2021; 22:404. [PMID: 34140041 PMCID: PMC8212499 DOI: 10.1186/s13063-021-05272-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 04/15/2021] [Indexed: 11/29/2022] Open
Abstract
Background IMI2-PainCare-BioPain-RCT3 is one of four similarly designed clinical studies aiming at profiling a set of functional biomarkers of drug effects on the nociceptive system that could serve to accelerate the future development of analgesics, by providing a quantitative understanding between drug exposure and effects of the drug on nociceptive signal processing in human volunteers. IMI2-PainCare-BioPain-RCT3 will focus on biomarkers derived from non-invasive electroencephalographic (EEG) measures of brain activity. Methods This is a multisite single-dose, double-blind, randomized, placebo-controlled, 4-period, 4-way crossover, pharmacodynamic (PD) and pharmacokinetic (PK) study in healthy subjects. Biomarkers derived from scalp EEG measurements (laser-evoked brain potentials [LEPs], pinprick-evoked brain potentials [PEPs], resting EEG) will be obtained before and three times after administration of three medications known to act on the nociceptive system (lacosamide, pregabalin, tapentadol) and placebo, given as a single oral dose in separate study periods. Medication effects will be assessed concurrently in a non-sensitized normal condition and a clinically relevant hyperalgesic condition (high-frequency electrical stimulation of the skin). Patient-reported outcomes will also be collected. A sequentially rejective multiple testing approach will be used with overall alpha error of the primary analysis split between LEP and PEP under tapentadol. Remaining treatment arm effects on LEP or PEP or effects on EEG are key secondary confirmatory analyses. Complex statistical analyses and PK-PD modeling are exploratory. Discussion LEPs and PEPs are brain responses related to the selective activation of thermonociceptors and mechanonociceptors. Their amplitudes are dependent on the responsiveness of these nociceptors and the state of the pathways relaying nociceptive input at the level of the spinal cord and brain. The magnitude of resting EEG oscillations is sensitive to changes in brain network function, and some modulations of oscillation magnitude can relate to perceived pain intensity, variations in vigilance, and attentional states. These oscillations can also be affected by analgesic drugs acting on the central nervous system. For these reasons, IMI2-PainCare-BioPain-RCT3 hypothesizes that EEG-derived measures can serve as biomarkers of target engagement of analgesic drugs for future Phase 1 clinical trials. Phase 2 and 3 clinical trials could also benefit from these tools for patient stratification. Trial registration This trial was registered 25/06/2019 in EudraCT (2019%2D%2D001204-37).
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Affiliation(s)
- André Mouraux
- Institute of Neuroscience (IoNS), UCLouvain, Brussels, Belgium.
| | - Petra Bloms-Funke
- Translational Science & Intelligence, Grünenthal GmbH, Aachen, Germany
| | - Irmgard Boesl
- Clinical Science Development, Grünenthal GmbH, Aachen, Germany
| | - Ombretta Caspani
- Department of Neurophysiology, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | | | | | - Nanna Brix Finnerup
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Luis Garcia-Larrea
- Lyon Neurosciences Center Research Unit Inserm U 1028, Pierre Wertheimer Hospital, Hospices Civils de Lyon, Lyon 1 University, Lyon, France
| | | | - Anna Kostenko
- Department of Neurophysiology, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | | | - Esther Pogatzki-Zahn
- Department of Anaesthesiology, Intensive Care and Pain Medicine, University Hospital Münster, Münster, Germany
| | | | | | - Andrea Truini
- Department of Human Neuroscience, Sapienza University, Rome, Italy
| | - Irene Tracey
- Wellcome Centre for Integrative Neuroimaging, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Iñaki F Troconiz
- Department of Pharmaceutical Technology and Chemistry, School of Pharmacy and Nutrition, University of Navarra, Pamplona, Spain
| | | | - Jose Miguel Vela
- Drug Discovery & Preclinical Development, ESTEVE Pharmaceuticals, Barcelona, Spain
| | - Katy Vincent
- Nuffield Department of Women's and Reproductive Health (NDWRH), University of Oxford, Oxford, UK
| | - Jan Vollert
- Pain Research, Department of Surgery and Cancer, Imperial College London, London, UK
| | - Vishvarani Wanigasekera
- Wellcome Centre for Integrative Neuroimaging, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Matthias Wittayer
- Department of Neurophysiology, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | | | - Rolf-Detlef Treede
- Department of Neurophysiology, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
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26
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Lenoir D, Willaert W, Coppieters I, Malfliet A, Ickmans K, Nijs J, Vonck K, Meeus M, Cagnie B. Electroencephalography During Nociceptive Stimulation in Chronic Pain Patients: A Systematic Review. PAIN MEDICINE 2021; 21:3413-3427. [PMID: 32488229 DOI: 10.1093/pm/pnaa131] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND With its high temporal resolution, electroencephalography (EEG), a technique that records electrical activity of cortical neuronal cells, is a potentially suitable technique to investigate human somatosensory processing. By using EEG, the processing of (nociceptive) stimuli can be investigated, along with the functionality of the nociceptive pathway. Therefore, it can be applied in chronic pain patients to objectify whether changes have occurred in nociceptive processing. Typically, so-called event-related potential (ERP) recordings are used, where EEG signals are recorded in response to specific stimuli and characterized by latency and amplitude. OBJECTIVE To summarize whether differences in somatosensory processing occur between chronic pain patients and healthy controls, measured with ERPs, and determine whether this response is related to the subjective pain intensity. DESIGN Systematic review. SETTING AND METHODS PubMed, Web of Science, and Embase were consulted, and 18 case-control studies were finally included. SUBJECTS The chronic pain patients suffered from tension-type headache, back pain, migraine, fibromyalgia, carpal tunnel syndrome, prostatitis, or complex regional pain syndrome. RESULTS Chronic neuropathic pain patients showed increased latencies of the N2 and P2 components, along with a decreased amplitude of the N2-P2 complex, which was also obtained in FM patients with small fiber dysfunction. The latter also showed a decreased amplitude of the N2-P3 and N1-P1 complex. For the other chronic pain patients, the latencies and the amplitudes of the ERP components did not seem to differ from healthy controls. One paper indicated that the N2-P3 peak-to-peak amplitude correlates with the subjective experience of the stimulus. CONCLUSIONS Differences in ERPs with healthy controls can mostly be found in chronic pain populations that suffer from neuropathic pain or where fiber dysfunction is present. In chronic pain populations with other etiological mechanisms, limited differences were found or agreed upon across studies.
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Affiliation(s)
- Dorine Lenoir
- Pain in Motion International Research Group.,Department of Physiotherapy, Human Physiology and Anatomy (KIMA), Faculty of Physical Education & Physiotherapy, Pain in Motion International Research Group, Vrije Universiteit Brussel, Brussel, Belgium.,Department of Physical Medicine and Physiotherapy, Universitair Ziekenhuis Brussel, Brussels, Belgium.,Research Foundation - Flanders (FWO), Brussels, Belgium
| | - Ward Willaert
- Pain in Motion International Research Group.,Department of Physiotherapy, Human Physiology and Anatomy (KIMA), Faculty of Physical Education & Physiotherapy, Pain in Motion International Research Group, Vrije Universiteit Brussel, Brussel, Belgium.,Department of Physical Medicine and Physiotherapy, Universitair Ziekenhuis Brussel, Brussels, Belgium.,Research Foundation - Flanders (FWO), Brussels, Belgium.,Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Iris Coppieters
- Pain in Motion International Research Group.,Department of Physiotherapy, Human Physiology and Anatomy (KIMA), Faculty of Physical Education & Physiotherapy, Pain in Motion International Research Group, Vrije Universiteit Brussel, Brussel, Belgium.,Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Anneleen Malfliet
- Pain in Motion International Research Group.,Department of Physiotherapy, Human Physiology and Anatomy (KIMA), Faculty of Physical Education & Physiotherapy, Pain in Motion International Research Group, Vrije Universiteit Brussel, Brussel, Belgium
| | - Kelly Ickmans
- Pain in Motion International Research Group.,Department of Physiotherapy, Human Physiology and Anatomy (KIMA), Faculty of Physical Education & Physiotherapy, Pain in Motion International Research Group, Vrije Universiteit Brussel, Brussel, Belgium.,Department of Physical Medicine and Physiotherapy, Universitair Ziekenhuis Brussel, Brussels, Belgium.,Research Foundation - Flanders (FWO), Brussels, Belgium
| | - Jo Nijs
- Department of Physiotherapy, Human Physiology and Anatomy (KIMA), Faculty of Physical Education & Physiotherapy, Pain in Motion International Research Group, Vrije Universiteit Brussel, Brussel, Belgium
| | - Kristl Vonck
- Department of Neurology, 4Brain, Ghent University Hospital, Ghent, Belgium
| | - Mira Meeus
- Pain in Motion International Research Group.,Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.,Department of Rehabilitation Sciences and Physiotherapy - MOVANT Research Group, Faculty of Medicine and Health Science, University of Antwerp, Antwerp, Belgium
| | - Barbara Cagnie
- Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
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27
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Tucker-Bartley A, Lemme J, Gomez-Morad A, Shah N, Veliu M, Birklein F, Storz C, Rutkove S, Kronn D, Boyce AM, Kraft E, Upadhyay J. Pain Phenotypes in Rare Musculoskeletal and Neuromuscular Diseases. Neurosci Biobehav Rev 2021; 124:267-290. [PMID: 33581222 PMCID: PMC9521731 DOI: 10.1016/j.neubiorev.2021.02.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 01/18/2021] [Accepted: 02/03/2021] [Indexed: 12/11/2022]
Abstract
For patients diagnosed with a rare musculoskeletal or neuromuscular disease, pain may transition from acute to chronic; the latter yielding additional challenges for both patients and care providers. We assessed the present understanding of pain across a set of ten rare, noninfectious, noncancerous disorders; Osteogenesis Imperfecta, Ehlers-Danlos Syndrome, Achondroplasia, Fibrodysplasia Ossificans Progressiva, Fibrous Dysplasia/McCune-Albright Syndrome, Complex Regional Pain Syndrome, Duchenne Muscular Dystrophy, Infantile- and Late-Onset Pompe disease, Charcot-Marie-Tooth Disease, and Amyotrophic Lateral Sclerosis. Through the integration of natural history, cross-sectional, retrospective, clinical trials, & case studies we described pathologic and genetic factors, pain sources, phenotypes, and lastly, existing therapeutic approaches. We highlight that while rare diseases possess distinct core pathologic features, there are a number of shared pain phenotypes and mechanisms that may be prospectively examined and therapeutically targeted in a parallel manner. Finally, we describe clinical and research approaches that may facilitate more accurate diagnosis, monitoring, and treatment of pain as well as elucidation of the evolving nature of pain phenotypes in rare musculoskeletal or neuromuscular illnesses.
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Affiliation(s)
- Anthony Tucker-Bartley
- Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Jordan Lemme
- Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Andrea Gomez-Morad
- Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Nehal Shah
- Department of Radiology, Brigham and Women's Hospital, Boston, MA, 02115, USA
| | - Miranda Veliu
- Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Frank Birklein
- Department of Neurology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Rhineland-Palatinate, 55131, Germany
| | - Claudia Storz
- Department of Orthopedics, Physical Medicine and Rehabilitation, University Hospital LMU Munich, Munich, Bavaria, 80539, Germany
| | - Seward Rutkove
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, 02215, USA
| | - David Kronn
- Department of Pathology and Pediatrics, New York Medical College, Valhalla, NY, 10595, USA; Medical Genetics, Inherited Metabolic & Lysosomal Storage Disorders Center, Boston Children's Health Physicians, Westchester, NY, 10532, USA
| | - Alison M Boyce
- Skeletal Disorders and Mineral Homeostasis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Eduard Kraft
- Department of Orthopedics, Physical Medicine and Rehabilitation, University Hospital LMU Munich, Munich, Bavaria, 80539, Germany; Interdisciplinary Pain Unit, University Hospital LMU Munich, Munich, 80539, Germany
| | - Jaymin Upadhyay
- Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA; Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, MA, 02478, USA.
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28
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Neurophysiologic assessment of small fibre damage in chemotherapy-induced peripheral neuropathy. Clin Neurophysiol 2021; 132:1947-1956. [PMID: 34034962 DOI: 10.1016/j.clinph.2021.02.406] [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] [Received: 08/16/2020] [Revised: 02/16/2021] [Accepted: 02/28/2021] [Indexed: 11/23/2022]
Abstract
OBJECTIVE In patients with chemotherapy-induced peripheral neuropathy (CIPN), demonstration of small fibre (SF) damage is important to understand chronic late effects. METHODS Thirty patients having complaints compatible with possible CIPN following treatment with oxaliplatin or docetaxel were compared with 27 healthy subjects. All subjects were evaluated with quantitative sensory testing (QST) assessing SF function and laser evoked potentials (LEP). In addition, SF-damage was assessed using cutaneous silent periods evoked with electrical (El-CSP) and laser (Ls-CSP) stimuli. RESULTS For LEP, N2P2 amplitudes were significantly smaller in patients than controls in both upper (P = 0.007) and lower extremities (P = 0.002), and the N1 amplitude in upper extremities of patients were significantly smaller than in controls (P = 0.001). SF-QST, LEP, Ls-CSP, and El-CSP were abnormal in 10 (33.3%), 16 (53.3%), 19 (63.3%), and 24 (80%) of CIPN patients, respectively. CONCLUSIONS In patients with possible CIPN, El-CSP and Ls-CSP were more often abnormal than LEP and QST. This is probably because El-CSP and Ls-CSP inform mainly about peripheral nociceptive fibres, while LEP and QST inform about peripheral and central nociceptive pathways together. SIGNIFICANCE LEP and QST are established methods to detect SF-damage. El- and Ls-CSP might help clinicians in diagnosing SF-damage.
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29
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A reappraisal of the presence of small or large fiber neuropathy in patients with erythromelalgia. Neurophysiol Clin 2021; 51:349-355. [PMID: 33888389 DOI: 10.1016/j.neucli.2021.03.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/31/2021] [Accepted: 03/31/2021] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE To assess the contribution of large and small nerve fiber alteration in erythromelalgia (EM). METHODS Thirty-three EM patients were included and underwent clinical evaluation based on EM severity score, DN4, and Utah Early Neuropathy Scale (UENS) score. Neurophysiological evaluation consisted in nerve conduction studies (NCS) for large nerve fibers and specific tests for small nerve fibers: electrochemical skin conductance, cold and warm detection thresholds, and laser evoked potentials. Finally, the evaluation of vascular changes was based on the presence of clinical feature of microvascular disorders and the measurement of the Toe Pressure Index (TPI). RESULTS While 28 patients (85%) had vascular alteration on TPI or clinical features, 23 patients (70%) had small-fiber neuropathy on neurophysiological tests, and only 10 patients (30%) had large fiber neuropathy on NCS. Regarding clinical scores, there was no difference between groups (presence or absence of large- or small-fiber neuropathy or microvascular disorder) except for a higher UENS score in patients with large fiber neuropathy. CONCLUSION Peripheral neuropathy, mostly involving small nerve fibers, is almost as common as microvascular changes in EM, but remains inconstant and not related to a specific neuropathic pattern or higher clinical severity. SIGNIFICANCE The association of neuropathic and vascular factors is not systematic in EM, this syndrome being characterized by different pathophysiological mechanisms leading to a common clinical phenotype.
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30
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Rosner J, Scheuren PS, Stalder SA, Curt A, Hubli M. Pinprick Evoked Potentials-Reliable Acquisition in Healthy Human Volunteers. PAIN MEDICINE 2021; 21:736-746. [PMID: 31216028 DOI: 10.1093/pm/pnz126] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
OBJECTIVE Pinprick evoked potentials (PEPs) represent a novel tool to assess the functional integrity of mechano-nociceptive pathways with a potential toward objectifying sensory deficits and gain seen in neurological disorders. The aim of the present study was to evaluate the feasibility and reliability of PEPs with respect to age, stimulation site, and skin type. METHODS Electroencephalographic responses evoked by two pinprick stimulation intensities (128 mN and 256 mN) applied at three sites (hand dorsum, palmar digit II, and foot dorsum) were recorded in 30 healthy individuals. Test-retest reliability was performed for the vertex negative-positive complex amplitudes, N-latencies, and pain ratings evoked by the 256mN stimulation intensity. RESULTS Feasibility of PEP acquisition was demonstrated across age groups, with higher proportions of evoked potentials (>85%) for the 256mN stimulation intensity. Reliability analyses, that is, Bland-Altman and intraclass correlation coefficients, revealed poor to excellent reliability upon retest depending on the stimulation sites. CONCLUSIONS This study highlights the reliability of PEP acquisition from cervical and lumbar segments across clinically representative age groups. Future methodological improvements might further strengthen PEP reliability in order to complement clinical neurophysiology of sensory nerve fibers by a more specific assessment of mechano-nociceptive pathways. Beyond looking at sensory deficits, PEPs may also become applicable to revealing signs of central sensitization, complementing the clinical assessment of mechanical hyperalgesia.
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Affiliation(s)
- Jan Rosner
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Paulina Simonne Scheuren
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Stephanie Anja Stalder
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Armin Curt
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Michèle Hubli
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
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31
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An intensity matched comparison of laser- and contact heat evoked potentials. Sci Rep 2021; 11:6861. [PMID: 33767259 PMCID: PMC7994633 DOI: 10.1038/s41598-021-85819-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 01/28/2021] [Indexed: 11/08/2022] Open
Abstract
Previous studies comparing laser (LEPs) and contact heat evoked potentials (CHEPs) consistently reported higher amplitudes following laser compared to contact heat stimulation. However, none of the studies matched the perceived pain intensity, questioning if the observed difference in amplitude is due to biophysical differences between the two methods or a mismatch in stimulation intensity. The aims of the current study were twofold: (1) to directly compare the brain potentials induced by intensity matched laser and contact heat stimulation and (2) investigate how capsaicin-induced secondary hyperalgesia modulates LEPs and CHEPs. Twenty-one healthy subjects were recruited and measured at four experimental sessions: (1) CHEPs + sham, (2) LEPs + sham, (3) CHEPs + capsaicin, and (4) LEPs + capsaicin. Baseline (sham) LEPs latency was significantly shorter and amplitude significantly larger compared to CHEPs, even when matched for perceived pain. Neither CHEPs nor LEPs was sensitive enough to detect secondary hyperalgesia. These differences provide evidence that a faster heating rate results in an earlier and more synchronized LEPs than CHEPs. To our knowledge, this was the first study to match perceived intensity of contact heat and laser stimulations, revealing distinct advantages associated with the acquisition of LEPs.
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Zhang J, Embray L, Yanovsky Y, Brankačk J, Draguhn A. A New Apparatus for Recording Evoked Responses to Painful and Non-painful Sensory Stimulation in Freely Moving Mice. Front Neurosci 2021; 15:613801. [PMID: 33642977 PMCID: PMC7907443 DOI: 10.3389/fnins.2021.613801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Accepted: 01/20/2021] [Indexed: 11/25/2022] Open
Abstract
Experiments on pain processing in animals face several methodological challenges including the reproducible application of painful stimuli. Ideally, behavioral and physiological correlates of pain should be assessed in freely behaving mice, avoiding stress, fear or behavioral restriction as confounding factors. Moreover, the time of pain-evoked brain activity should be precisely related to the time of stimulation, such that pain-specific neuronal activity can be unambiguously identified. This can be achieved with laser-evoked heat stimuli which are also well established for human pain research. However, laser-evoked neuronal potentials are rarely investigated in awake unrestrained rodents, partially due to the practical difficulties in precisely and reliably targeting and triggering stimulation. In order to facilitate such studies we have developed a versatile stimulation and recording system for freely moving mice. The custom-made apparatus can provide both laser- and mechanical stimuli with simultaneous recording of evoked potentials and behavioral responses. Evoked potentials can be recorded from superficial and deep brain areas showing graded pain responses which correlate with pain-specific behavioral reactions. Non-painful mechanical stimuli can be applied as a control, yielding clearly different electrophysiological and behavioral responses. The apparatus is suited for simultaneous acquisition of precisely timed electrophysiological and behavioral evoked responses in freely moving mice. Besides its application in pain research it may be also useful in other fields of sensory physiology.
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Affiliation(s)
- Jiaojiao Zhang
- Institute of Physiology and Pathophysiology, Medical Faculty Heidelberg, University of Heidelberg, Heidelberg, Germany
| | - Lee Embray
- Institute of Physiology and Pathophysiology, Medical Faculty Heidelberg, University of Heidelberg, Heidelberg, Germany
| | - Yevgenij Yanovsky
- Institute of Physiology and Pathophysiology, Medical Faculty Heidelberg, University of Heidelberg, Heidelberg, Germany
| | - Jurij Brankačk
- Institute of Physiology and Pathophysiology, Medical Faculty Heidelberg, University of Heidelberg, Heidelberg, Germany
| | - Andreas Draguhn
- Institute of Physiology and Pathophysiology, Medical Faculty Heidelberg, University of Heidelberg, Heidelberg, Germany
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Electrodiagnostic Testing of Small Fiber Neuropathies: A Review of Existing Guidelines. J Clin Neurophysiol 2020; 37:288-293. [PMID: 33151659 DOI: 10.1097/wnp.0000000000000681] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
This article reviews the literature on neurophysiological techniques for the diagnosis of small fiber neuropathy. The review is focused on clinical approach to suspected small fiber neuropathy, letting aside techniques whose clinical applicability is doubtful. We include, however, the special techniques required to examine C and Aδ fibers, which cannot be evaluated directly with conventional neurophysiological methods. The most relevant publications are summarized and recommendations for the clinical assessment of small fiber neuropathy are provided.
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Goudman L, Daenen L, Mouraux A, Nijs J, Cras P, Roussel N, Moens M, Coppieters I, Huysmans E, De Kooning M. Processing of Laser-Evoked Potentials in Patients with Chronic Whiplash-Associated Disorders, Chronic Fatigue Syndrome, and Healthy Controls: A Case-Control Study. PAIN MEDICINE 2020; 21:2553-2563. [PMID: 32289826 DOI: 10.1093/pm/pnaa068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Laser-evoked potentials (LEPs) are among the reliable neurophysiological tools to investigate patients with neuropathic pain, as they can provide an objective account of the functional status of thermo-nociceptive pathways. The goal of this study was to explore the functioning of the nociceptive afferent pathways by examining LEPs in patients with chronic whiplash-associated disorders (cWAD), patients with chronic fatigue syndrome (CFS), and healthy controls (HCs). DESIGN Case-control study. SETTING A single medical center in Belgium. SUBJECTS The LEPs of 21 patients with cWAD, 19 patients with CFS, and 18 HCs were analyzed in this study. METHODS All participants received brief nociceptive CO2 laser stimuli applied to the dorsum of the left hand and left foot while brain activity was recorded with a 32-channel electroencephalogram (EEG). LEP signals and transient power modulations were compared between patient groups and HCs. RESULTS No between-group differences were found for stimulus intensity, which was supraliminal for Aδ fibers. The amplitudes and latencies of LEP wave components N1, N2, and P2 in patients with cWAD and CFS were statistically similar to those of HCs. There were no significant differences between the time-frequency maps of EEG oscillation amplitude between HCs and both patient populations. CONCLUSIONS EEG responses of heat-sensitive Aδ fibers in patients with cWAD and CFS revealed no significant differences from the responses of HCs. These findings thus do not support a state of generalized central nervous system hyperexcitability in those patients.
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Affiliation(s)
- Lisa Goudman
- Department of Neurosurgery, Universitair Ziekenhuis Brussel, Brussels, Belgium.,Pain in Motion International Research Group.,Department of Physiotherapy, Human Physiology and Anatomy, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium
| | - Liesbeth Daenen
- Pain in Motion International Research Group.,Department of Physiotherapy, Human Physiology and Anatomy, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium.,Knowledge, Information and Research Center (KIR), Group Idewe, Louvain, Belgium
| | - Andre Mouraux
- Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Jo Nijs
- Pain in Motion International Research Group.,Department of Physiotherapy, Human Physiology and Anatomy, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium.,Department of Physical Medicine and Physiotherapy, Universitair Ziekenhuis Brussel, Brussels, Belgium
| | - Patrick Cras
- Laboratory of Neurology, Translational Neurosciences, University of Antwerp, Wilrijk, Belgium.,Institute Born-Bunge, University of Antwerp, Wilrijk, Belgium.,Department of Neurology, Antwerp University Hospital, Edegem, Belgium
| | - Nathalie Roussel
- Department of Rehabilitation Sciences and Physiotherapy (MOVANT), Faculty of Medicine and Health Sciences, University of Antwerp, Campus, Drie Eiken, Wilrijk, Belgium
| | - Maarten Moens
- Department of Neurosurgery, Universitair Ziekenhuis Brussel, Brussels, Belgium.,Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Brussels, Belgium.,Department of Radiology, Universitair Ziekenhuis Brussel, Brussels, Belgium
| | - Iris Coppieters
- Pain in Motion International Research Group.,Department of Physiotherapy, Human Physiology and Anatomy, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium.,Department of Physical Medicine and Physiotherapy, Universitair Ziekenhuis Brussel, Brussels, Belgium
| | - Eva Huysmans
- Pain in Motion International Research Group.,Department of Physiotherapy, Human Physiology and Anatomy, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium.,Department of Physical Medicine and Physiotherapy, Universitair Ziekenhuis Brussel, Brussels, Belgium.,Department of Public Health (GEWE), Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Brussels, Belgium
| | - Margot De Kooning
- Pain in Motion International Research Group.,Department of Physiotherapy, Human Physiology and Anatomy, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium.,Department of Physical Medicine and Physiotherapy, Universitair Ziekenhuis Brussel, Brussels, Belgium
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Bassez I, Ricci K, Vecchio E, Delussi M, Gentile E, Marinazzo D, de Tommaso M. The effect of painful laser stimuli on EEG gamma-band activity in migraine patients and healthy controls. Clin Neurophysiol 2020; 131:1755-1766. [DOI: 10.1016/j.clinph.2020.04.157] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 03/09/2020] [Accepted: 04/15/2020] [Indexed: 01/03/2023]
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Vecchio E, Lombardi R, Paolini M, Libro G, Delussi M, Ricci K, Quitadamo SG, Gentile E, Girolamo F, Iannone F, Lauria G, de Tommaso M. Peripheral and central nervous system correlates in fibromyalgia. Eur J Pain 2020; 24:1537-1547. [PMID: 32478943 DOI: 10.1002/ejp.1607] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 05/14/2020] [Accepted: 05/21/2020] [Indexed: 12/11/2022]
Abstract
BACKGROUND Fibromyalgia (FM) is a syndrome characterized by altered pain processing at central and peripheral level, whose pathophysiologic mechanisms remain obscure. We aimed at exploring the structural changes of peripheral nociceptor measured by skin biopsy, the functional changes of central nociceptive pathway assessed by laser-evoked potentials (LEP), and their correlation with clinical features and comorbidities. METHODS In all, 81 patients diagnosed with FM underwent skin biopsies with quantification of intraepidermal nerve fibre density (IENFD) at the thigh and distal leg, and LEP recording by stimulating hand, thigh and foot. Nerve conduction study (NCS), clinical features, comorbidity with migraine and mood disorders, and previous, non-active immune-mediated disorders were recorded. RESULTS Intraepidermal nerve fibre density was reduced in 85% of patients at the thigh and in 12.3% of patients at the distal leg, whereas it was normal in 14.8% of patients. N2P2 habituation index from laser stimulation at the thigh was altered in 97.5% of patients and correlated with reduced IENFD at the thigh. LEP latencies and amplitudes did not differ among groups. No association was found between IENFD, LEP, clinical features and comorbidities. CONCLUSIONS Fibromyalgia patients most commonly showed a mild loss of peripheral nociceptors at the thigh rather than distal small fibre neuropathy. This finding was associated with an altered habituation index and strengthened the hypothesis that central sensitization plays a key role in the pathogenesis of the disease. SIGNIFICANCE Central impairment of pain processing likely underlies FM, which in most patients is associated with mild proximal small fibre pathology.
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Affiliation(s)
- Eleonora Vecchio
- Applied Neurophysiology and Pain Unit, Department of Basic Medical Sciences Neurosciences and Sensory Organs, University of Bari "Aldo Moro", Bari, Italy
| | - Raffaella Lombardi
- 3rd Neurology Unit and Skin Biopsy, Department of Clinical Neurosciences, Peripheral Neuropathy and Neuropathic Pain Laboratory, IRCCS Foundation, 'Carlo Besta' Neurological Institute, Milan, Italy
| | - Matilde Paolini
- 3rd Neurology Unit and Skin Biopsy, Department of Clinical Neurosciences, Peripheral Neuropathy and Neuropathic Pain Laboratory, IRCCS Foundation, 'Carlo Besta' Neurological Institute, Milan, Italy
| | - Giuseppe Libro
- Applied Neurophysiology and Pain Unit, Department of Basic Medical Sciences Neurosciences and Sensory Organs, University of Bari "Aldo Moro", Bari, Italy
| | - Marianna Delussi
- Applied Neurophysiology and Pain Unit, Department of Basic Medical Sciences Neurosciences and Sensory Organs, University of Bari "Aldo Moro", Bari, Italy
| | - Katia Ricci
- Applied Neurophysiology and Pain Unit, Department of Basic Medical Sciences Neurosciences and Sensory Organs, University of Bari "Aldo Moro", Bari, Italy
| | - Silvia G Quitadamo
- Applied Neurophysiology and Pain Unit, Department of Basic Medical Sciences Neurosciences and Sensory Organs, University of Bari "Aldo Moro", Bari, Italy
| | - Eleonora Gentile
- Applied Neurophysiology and Pain Unit, Department of Basic Medical Sciences Neurosciences and Sensory Organs, University of Bari "Aldo Moro", Bari, Italy
| | - Francesco Girolamo
- Unit of Human Anatomy and Histology, Department of Basic Medical Sciences, Neurosciences and Sensory Organs, School of Medicine, University of Bari, Bari, Italy
| | - Florenzo Iannone
- Rheumatology Unit, Department of Emergency and Organ Transplantation, University of Bari, Bari, Italy
| | - Giuseppe Lauria
- 3rd Neurology Unit and Skin Biopsy, Department of Clinical Neurosciences, Peripheral Neuropathy and Neuropathic Pain Laboratory, IRCCS Foundation, 'Carlo Besta' Neurological Institute, Milan, Italy.,Department of Biomedical and Clinical Sciences "Luigi Sacco", University of Milan, Milan, Italy
| | - Marina de Tommaso
- Applied Neurophysiology and Pain Unit, Department of Basic Medical Sciences Neurosciences and Sensory Organs, University of Bari "Aldo Moro", Bari, Italy
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Farschtschi SC, Mainka T, Glatzel M, Hannekum AL, Hauck M, Gelderblom M, Hagel C, Friedrich RE, Schuhmann MU, Schulz A, Morrison H, Kehrer-Sawatzki H, Luhmann J, Gerloff C, Bendszus M, Bäumer P, Mautner VF. C-Fiber Loss as a Possible Cause of Neuropathic Pain in Schwannomatosis. Int J Mol Sci 2020; 21:ijms21103569. [PMID: 32443592 PMCID: PMC7278954 DOI: 10.3390/ijms21103569] [Citation(s) in RCA: 4] [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: 04/17/2020] [Revised: 05/09/2020] [Accepted: 05/15/2020] [Indexed: 01/22/2023] Open
Abstract
Schwannomatosis is the third form of neurofibromatosis and characterized by the occurrence of multiple schwannomas. The most prominent symptom is chronic pain. We aimed to test whether pain in schwannomatosis might be caused by small-fiber neuropathy. Twenty patients with schwannomatosis underwent neurological examination and nerve conduction studies. Levels of pain perception as well as anxiety and depression were assessed by established questionnaires. Quantitative sensory testing (QST) and laser-evoked potentials (LEP) were performed on patients and controls. Whole-body magnetic resonance imaging (wbMRI) and magnetic resonance neurography (MRN) were performed to quantify tumors and fascicular nerve lesions; skin biopsies were performed to determine intra-epidermal nerve fiber density (IENFD). All patients suffered from chronic pain without further neurological deficits. The questionnaires indicated neuropathic symptoms with significant impact on quality of life. Peripheral nerve tumors were detected in all patients by wbMRI. MRN showed additional multiple fascicular nerve lesions in 16/18 patients. LEP showed significant faster latencies compared to normal controls. Finally, IENFD was significantly reduced in 13/14 patients. Our study therefore indicates the presence of small-fiber neuropathy, predominantly of unmyelinated C-fibers. Fascicular nerve lesions are characteristic disease features that are associated with faster LEP latencies and decreased IENFD. Together these methods may facilitate differential diagnosis of schwannomatosis.
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Affiliation(s)
- Said C. Farschtschi
- Department of Neurology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (A.-L.H.); (M.H.); (M.G.); (J.L.); (C.G.); (V.-F.M.)
- Correspondence: ; Tel.: +49(0)407410-53869
| | - Tina Mainka
- Department of Neurology, Charité University Medicine, 10117 Berlin, Germany;
- Berlin Institute of Health, 10178 Berlin, Germany
| | - Markus Glatzel
- Department of Neuropathology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (M.G.); (C.H.)
| | - Anna-Lena Hannekum
- Department of Neurology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (A.-L.H.); (M.H.); (M.G.); (J.L.); (C.G.); (V.-F.M.)
| | - Michael Hauck
- Department of Neurology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (A.-L.H.); (M.H.); (M.G.); (J.L.); (C.G.); (V.-F.M.)
- Department of Neurophysiology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Mathias Gelderblom
- Department of Neurology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (A.-L.H.); (M.H.); (M.G.); (J.L.); (C.G.); (V.-F.M.)
| | - Christian Hagel
- Department of Neuropathology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (M.G.); (C.H.)
| | - Reinhard E. Friedrich
- Department of Maxillofacial Surgery, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany;
| | - Martin U. Schuhmann
- Department of Neurosurgery, University Medical Center Tübingen, 72076 Tübingen, Germany;
| | - Alexander Schulz
- Leibniz Institute on Aging, Fritz Lipmann Institute, 07745 Jena, Germany; (A.S.); (H.M.)
- MVZ Human Genetics, 99084 Erfurt, Germany
| | - Helen Morrison
- Leibniz Institute on Aging, Fritz Lipmann Institute, 07745 Jena, Germany; (A.S.); (H.M.)
| | | | - Jan Luhmann
- Department of Neurology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (A.-L.H.); (M.H.); (M.G.); (J.L.); (C.G.); (V.-F.M.)
| | - Christian Gerloff
- Department of Neurology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (A.-L.H.); (M.H.); (M.G.); (J.L.); (C.G.); (V.-F.M.)
| | - Martin Bendszus
- Department of Neuroradiology, University Medical Center Heidelberg, 69120 Heidelberg, Germany; (M.B.); (P.B.)
| | - Philipp Bäumer
- Department of Neuroradiology, University Medical Center Heidelberg, 69120 Heidelberg, Germany; (M.B.); (P.B.)
- Department of Radiology, German Cancer Research Center, 69120 Heidelberg, Germany
| | - Victor-Felix Mautner
- Department of Neurology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; (A.-L.H.); (M.H.); (M.G.); (J.L.); (C.G.); (V.-F.M.)
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de Tommaso M, Betti V, Bocci T, Bolognini N, Di Russo F, Fattapposta F, Ferri R, Invitto S, Koch G, Miniussi C, Piccione F, Ragazzoni A, Sartucci F, Rossi S, Arcara G, Berchicci M, Bianco V, Delussi M, Gentile E, Giovannelli F, Mannarelli D, Marino M, Mussini E, Pauletti C, Pellicciari MC, Pisoni A, Raggi A, Valeriani M. Pearls and pitfalls in brain functional analysis by event-related potentials: a narrative review by the Italian Psychophysiology and Cognitive Neuroscience Society on methodological limits and clinical reliability-part I. Neurol Sci 2020; 41:2711-2735. [PMID: 32388645 DOI: 10.1007/s10072-020-04420-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Accepted: 04/13/2020] [Indexed: 12/14/2022]
Abstract
Event-related potentials (ERPs) are obtained from the electroencephalogram (EEG) or the magnetoencephalogram (MEG, event-related fields (ERF)), extracting the activity that is time-locked to an event. Despite the potential utility of ERP/ERF in cognitive domain, the clinical standardization of their use is presently undefined for most of procedures. The aim of the present review is to establish limits and reliability of ERP medical application, summarize main methodological issues, and present evidence of clinical application and future improvement. The present section of the review focuses on well-standardized ERP methods, including P300, Contingent Negative Variation (CNV), Mismatch Negativity (MMN), and N400, with a chapter dedicated to laser-evoked potentials (LEPs). One section is dedicated to proactive preparatory brain activity as the Bereitschaftspotential and the prefrontal negativity (BP and pN). The P300 and the MMN potentials have a limited but recognized role in the diagnosis of cognitive impairment and consciousness disorders. LEPs have a well-documented usefulness in the diagnosis of neuropathic pain, with low application in clinical assessment of psychophysiological basis of pain. The other ERP components mentioned here, though largely applied in normal and pathological cases and well standardized, are still confined to the research field. CNV, BP, and pN deserve to be largely tested in movement disorders, just to explain possible functional changes in motor preparation circuits subtending different clinical pictures and responses to treatments.
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Affiliation(s)
- Marina de Tommaso
- Applied Neurophysiology and Pain Unit-AnpLab-University of Bari Aldo Moro, Bari, Italy
| | - Viviana Betti
- Department of Psychology, Sapienza University of Rome, Rome, Italy.,IRCCS Fondazione Santa Lucia (Santa Lucia Foundation), Rome, Italy
| | - Tommaso Bocci
- Department of Health Sciences, University of Milan, Milan, Italy
| | - Nadia Bolognini
- Department of Psychology & NeuroMi, University of Milano Bicocca, Milan, Italy.,Laboratory of Neuropsychology, IRCCS Istituto Auxologico, Milan, Italy
| | - Francesco Di Russo
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Rome, Italy
| | | | | | - Sara Invitto
- INSPIRE - Laboratory of Cognitive and Psychophysiological Olfactory Processes, University of Salento, Lecce, Italy
| | - Giacomo Koch
- IRCCS Fondazione Santa Lucia (Santa Lucia Foundation), Rome, Italy.,Department of Neuroscience, Policlinico Tor Vergata, Rome, Italy
| | - Carlo Miniussi
- Center for Mind/Brain Sciences - CIMeC, University of Trento, Rovereto, Italy.,Cognitive Neuroscience Section, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
| | - Francesco Piccione
- Brain Imaging and Neural Dynamics Research Group, IRCCS San Camillo Hospital, Venice, Italy
| | - Aldo Ragazzoni
- Unit of Neurology and Clinical Neurophysiology, Fondazione PAS, Scandicci, Florence, Italy
| | - Ferdinando Sartucci
- Section of Neurophysiopathology, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy.,CNR Institute of Neuroscience, Pisa, Italy
| | - Simone Rossi
- Department of Medicine, Surgery and Neuroscience Siena Brain Investigation and Neuromodulation Lab (SI-BIN Lab), University of Siena, Siena, Italy
| | - Giorgio Arcara
- Brain Imaging and Neural Dynamics Research Group, IRCCS San Camillo Hospital, Venice, Italy
| | - Marika Berchicci
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Rome, Italy
| | - Valentina Bianco
- IRCCS Fondazione Santa Lucia (Santa Lucia Foundation), Rome, Italy.,Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Rome, Italy
| | - Marianna Delussi
- Applied Neurophysiology and Pain Unit-AnpLab-University of Bari Aldo Moro, Bari, Italy
| | - Eleonora Gentile
- Applied Neurophysiology and Pain Unit-AnpLab-University of Bari Aldo Moro, Bari, Italy
| | - Fabio Giovannelli
- Section of Psychology - Department of Neuroscience, Psychology, Drug Research, Child Health, University of Florence, Florence, Italy
| | - Daniela Mannarelli
- Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy
| | - Marco Marino
- Brain Imaging and Neural Dynamics Research Group, IRCCS San Camillo Hospital, Venice, Italy
| | - Elena Mussini
- Department of Movement, Human and Health Sciences, University of Rome "Foro Italico", Rome, Italy
| | - Caterina Pauletti
- Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy
| | | | - Alberto Pisoni
- Department of Psychology & NeuroMi, University of Milano Bicocca, Milan, Italy
| | - Alberto Raggi
- Unit of Neurology, G.B. Morgagni - L. Pierantoni Hospital, Forlì, Italy
| | - Massimiliano Valeriani
- Neurology Ward Unit, Bambino Gesù Hospital, Rome, Italy. .,Center for Sensory-Motor Interaction, Aalborg University, Aalborg, Denmark.
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Fabry V, Gerdelat A, Acket B, Cintas P, Rousseau V, Uro-Coste E, Evrard SM, Pavy-Le Traon A. Which Method for Diagnosing Small Fiber Neuropathy? Front Neurol 2020; 11:342. [PMID: 32431663 PMCID: PMC7214721 DOI: 10.3389/fneur.2020.00342] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 04/07/2020] [Indexed: 01/12/2023] Open
Abstract
Introduction: Small fiber neuropathies (SFN) induce pain and/or autonomic symptoms. The diagnosis of SFN poses a challenge because the role of skin biopsy as a reference method and of each neurophysiological test remain to be discussed. This study compares six methods evaluating small sensory and autonomic nerve fibers: skin biopsy, Quantitative Sensory Testing (QST), quantitative sweat measurement system (Q-Sweat), Laser Evoked Potentials (LEP), Electrochemical Skin Conductance (ESC) measurement and Autonomic CardioVascular Tests (ACVT). Methods: This is a single center, retrospective study including patients tested for symptoms compatible with SFN between 2013 and 2016 using the afore-mentioned tests. Patients were ultimately classified according to the results and clinical features as "definite SFN," "possible SFN" or "no SFN." The sensitivity (Se) and specificity (Sp) of each test were calculated based on the final diagnosis and the best diagnostic strategy was then evaluated. Results: Two hundred and forty-five patients were enrolled (164 females (66.9%), age: 50.4 ± 15 years). The results are as follows: skin biopsy: Se = 58%, Sp = 91%; QST: Se = 72%, Sp = 39%; Q-Sweat: Se = 53%, Sp = 69%; LEP: Se = 66%, Sp = 89%; ESC: Se = 60%, Sp = 89%; Cardiovascular tests: Se = 15%, Sp = 99%. The combination of skin biopsy, LEP, QST and ESC has a Se of 90% and a Sp of 87%. Conclusion: Our study outlines the benefits of combining skin biopsy, ESC, LEP and QST in the diagnosis of SFN.
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Affiliation(s)
- Vincent Fabry
- Department of Neurology, Toulouse University Hospital, Toulouse, France.,University of Toulouse III Paul Sabatier, Toulouse, France
| | | | - Blandine Acket
- Department of Neurology, Toulouse University Hospital, Toulouse, France
| | - Pascal Cintas
- Department of Neurology, Toulouse University Hospital, Toulouse, France
| | - Vanessa Rousseau
- MeDatAS Unit, Department of Medical and Clinical Pharmacology, Toulouse University Hospital, Toulouse, France
| | - Emmanuelle Uro-Coste
- University of Toulouse III Paul Sabatier, Toulouse, France.,Department of Pathology, Toulouse University Hospital, IUC-Oncopole, Toulouse, France.,INSERM U1037, Cancer Research Center of Toulouse (CRCT), Toulouse, France
| | - Solène M Evrard
- University of Toulouse III Paul Sabatier, Toulouse, France.,Department of Pathology, Toulouse University Hospital, IUC-Oncopole, Toulouse, France.,INSERM U1037, Cancer Research Center of Toulouse (CRCT), Toulouse, France
| | - Anne Pavy-Le Traon
- Department of Neurology, Toulouse University Hospital, Toulouse, France.,University of Toulouse III Paul Sabatier, Toulouse, France.,Institute of Cardiovascular and Metabolic Diseases (I2MCUMR1048), Toulouse, France
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Zhou L, Bi Y, Liang M, Kong Y, Tu Y, Zhang X, Song Y, Du X, Tan S, Hu L. A modality-specific dysfunction of pain processing in schizophrenia. Hum Brain Mapp 2020; 41:1738-1753. [PMID: 31868305 PMCID: PMC7267942 DOI: 10.1002/hbm.24906] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 12/06/2019] [Accepted: 12/11/2019] [Indexed: 12/21/2022] Open
Abstract
Clinical observations showed that schizophrenia (SCZ) patients reported little or no pain under various conditions that are commonly associated with intense painful sensations, leading to a higher risk of morbidity and mortality. However, this phenomenon has received little attention and its underlying neural mechanisms remain unclear. Here, we conducted two experiments combining psychophysics, electroencephalography (EEG), and functional magnetic resonance imaging (fMRI) techniques to investigate neural mechanisms of pain insensitivity in SCZ patients. Specifically, we adopted a stimulus-response paradigm with brief stimuli of different sensory modalities (i.e., nociceptive, non-nociceptive somatosensory, and auditory) to test whether pain insensitivity in SCZ patients is supra-modal or modality-specific, and used EEG and fMRI techniques to clarify its neural mechanisms. We observed that perceived intensities to nociceptive stimuli were significantly smaller in SCZ patients than healthy controls, whereas perceived intensities to non-nociceptive somatosensory and auditory stimuli were not significantly different. The behavioral results were confirmed by stimulus-evoked brain responses sampled by EEG and fMRI techniques, thus verifying the modality-specific nature of the modulation of nociceptive information processing in SCZ patients. Additionally, significant group differences were observed in the spectral power of alpha oscillations in prestimulus EEG and the seed-based functional connectivity in resting-state fMRI (seeds: the thalamus and periaqueductal gray that are key nodes in ascending and descending pain pathways respectively), suggesting a possible contribution of cortical-subcortical dysfunction to the phenomenon. Overall, our study provides insight into the neural mechanisms of pain insensitivity in SCZ and highlights a need for systematic assessments of their pain-related diseases.
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Affiliation(s)
- Lili Zhou
- CAS Key Laboratory of Mental HealthInstitute of Psychology, Chinese Academy of SciencesBeijingChina
- Department of PsychologyUniversity of Chinese Academy of SciencesBeijingChina
| | - Yanzhi Bi
- CAS Key Laboratory of Mental HealthInstitute of Psychology, Chinese Academy of SciencesBeijingChina
- Department of PsychologyUniversity of Chinese Academy of SciencesBeijingChina
| | - Meng Liang
- School of Medical Imaging and Tianjin Key Laboratory of Functional ImagingTianjin Medical UniversityTianjinChina
| | - Yazhuo Kong
- Department of PsychologyUniversity of Chinese Academy of SciencesBeijingChina
- CAS Key Laboratory of Behavioural ScienceInstitute of Psychology, Chinese Academy of SciencesBeijingChina
| | - Yiheng Tu
- Department of PsychiatryMassachusetts General Hospital and Harvard Medical SchoolCharlestownMassachusetts
| | - Xiangyang Zhang
- CAS Key Laboratory of Mental HealthInstitute of Psychology, Chinese Academy of SciencesBeijingChina
- Department of PsychologyUniversity of Chinese Academy of SciencesBeijingChina
| | - Yanying Song
- Psychiatry Research CentreBeijing Huilonguan HospitalBeijingChina
| | - Xia Du
- Psychiatry Research CentreBeijing Huilonguan HospitalBeijingChina
| | - Shuping Tan
- Psychiatry Research CentreBeijing Huilonguan HospitalBeijingChina
| | - Li Hu
- CAS Key Laboratory of Mental HealthInstitute of Psychology, Chinese Academy of SciencesBeijingChina
- Department of PsychologyUniversity of Chinese Academy of SciencesBeijingChina
- Department of Pain ManagementThe State Key Clinical Specialty in Pain Medicine, The Second Affiliated Hospital of Guangzhou Medical UniversityGuangzhouChina
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Heid C, Mouraux A, Treede RD, Schuh-Hofer S, Rupp A, Baumgärtner U. Early gamma-oscillations as correlate of localized nociceptive processing in primary sensorimotor cortex. J Neurophysiol 2020; 123:1711-1726. [PMID: 32208893 DOI: 10.1152/jn.00444.2019] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Recent studies put forward the idea that stimulus-evoked gamma-band oscillations (GBOs; 30-100 Hz) play a specific role in nociception. So far, evidence for the specificity of GBOs for nociception, their possible involvement in nociceptive sensory discriminatory abilities, and knowledge regarding their cortical sources is just starting to grow. To address these questions, we used electroencephalography (EEG) to record brain activity evoked by phasic nociceptive laser stimuli and tactile stimuli applied at different intensities to the right hand and foot of 12 healthy volunteers. The EEG was analyzed in the time domain to extract phase-locked event-related brain potentials (ERPs) and in three regions of interest in the time-frequency domain (delta/theta, 40-Hz gamma, 70-Hz gamma) to extract stimulus-evoked changes in the magnitude of non-phase-locked brain oscillations. Both nociceptive and tactile stimuli, matched with respect to subjective intensity, elicited phase locked ERPs of increasing amplitude with increasing stimulus intensity. In contrast, only nociceptive stimuli elicited a significant enhancement of GBOs (65-85 Hz, 150-230 ms after stimulus onset), whose magnitude encoded stimulus intensity, whereas tactile stimuli led to a GBO decrease. Following nociceptive hand stimulation, the topographical distribution of GBOs was maximal at contralateral electrode C3, whereas maximum activity following foot stimulation was recorded at the midline electrode Cz, compatible with generation of GBOs in the representations of the hand and foot of the primary sensorimotor cortex, respectively. The differential behavior of high-frequency GBOs and low-frequency 40-Hz GBOs is indicating different functional roles and regions in sensory processing.NEW & NOTEWORTHY Gamma-band oscillations show hand-foot somatotopy compatible with generation in primary sensorimotor cortex and are present following nociceptive but not tactile stimulation of the hand and foot in humans.
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Affiliation(s)
- C Heid
- Department of Neurophysiology, Mannheim Center for Translational Neurosciences (MCTN), University of Heidelberg, Mannheim, Germany
| | - A Mouraux
- Institute of Neuroscience (IONS), Université catholique de Louvain, Brussels B-1200, Belgium
| | - R-D Treede
- Department of Neurophysiology, Mannheim Center for Translational Neurosciences (MCTN), University of Heidelberg, Mannheim, Germany
| | - S Schuh-Hofer
- Department of Neurophysiology, Mannheim Center for Translational Neurosciences (MCTN), University of Heidelberg, Mannheim, Germany
| | - A Rupp
- Department of Neurology, Section of Biomagnetism, University of Heidelberg, Heidelberg, Germany
| | - U Baumgärtner
- Department of Neurophysiology, Mannheim Center for Translational Neurosciences (MCTN), University of Heidelberg, Mannheim, Germany.,Department of Human Medicine, Faculty of Life Sciences, Medical School Hamburg (MSH), Hamburg, Germany
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42
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Gentile E, Ricci K, Vecchio E, Libro G, Delussi M, Casas-Barragàn A, de Tommaso M. A Simple Pattern of Movement is not Able to Inhibit Experimental Pain in FM Patients and Controls: an sLORETA Study. Brain Sci 2020; 10:E190. [PMID: 32214053 PMCID: PMC7139913 DOI: 10.3390/brainsci10030190] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 03/09/2020] [Accepted: 03/23/2020] [Indexed: 12/27/2022] Open
Abstract
Motor cortex activation seems to induce an analgesic effect on pain that would be different between patients with fibromyalgia (FM) and control subjects. This study was conducted to analyze the changes of the laser-evoked potentials (LEPs) induced during a finger tapping task in the FM patients and the controls employing a multi-dipolar analysis according to Standardized low resolution brain electromagnetic tomography (sLORETA) method. The LEPs from 38 FM patients and 21 controls were analyzed. The LEPs were recorded while subjects performed a slow and a fast finger tapping task. We confirmed that the difference between N1, N2 and P2 wave amplitudes between conditions and groups was not significant. In control subjects, the fast finger tapping task induced a modification of cortical source activation in the main areas processing laser stimulation from the moving hand independently from the movement speed. In summary, a simple and repetitive movement is not able to induce consistent inhibition of experimental pain evoked by the moving and the not moving hand in each group. It could interfere with LEP sources within the limbic area at least in control subjects, without inhibit cortical responses or explain the different pattern of motor and pain interaction in FM patients.
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Affiliation(s)
- Eleonora Gentile
- Applied Neurophysiology and Pain Unit, SMBNOS Department, Bari Aldo Moro University, Polyclinic General Hospital, 70121 Bari, Italy; (K.R.); (E.V.); (G.L.); (M.D.); (M.d.T.)
| | - Katia Ricci
- Applied Neurophysiology and Pain Unit, SMBNOS Department, Bari Aldo Moro University, Polyclinic General Hospital, 70121 Bari, Italy; (K.R.); (E.V.); (G.L.); (M.D.); (M.d.T.)
| | - Eleonora Vecchio
- Applied Neurophysiology and Pain Unit, SMBNOS Department, Bari Aldo Moro University, Polyclinic General Hospital, 70121 Bari, Italy; (K.R.); (E.V.); (G.L.); (M.D.); (M.d.T.)
| | - Giuseppe Libro
- Applied Neurophysiology and Pain Unit, SMBNOS Department, Bari Aldo Moro University, Polyclinic General Hospital, 70121 Bari, Italy; (K.R.); (E.V.); (G.L.); (M.D.); (M.d.T.)
| | - Marianna Delussi
- Applied Neurophysiology and Pain Unit, SMBNOS Department, Bari Aldo Moro University, Polyclinic General Hospital, 70121 Bari, Italy; (K.R.); (E.V.); (G.L.); (M.D.); (M.d.T.)
| | | | - Marina de Tommaso
- Applied Neurophysiology and Pain Unit, SMBNOS Department, Bari Aldo Moro University, Polyclinic General Hospital, 70121 Bari, Italy; (K.R.); (E.V.); (G.L.); (M.D.); (M.d.T.)
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43
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Di Stefano G, Di Lionardo A, La Cesa S, Di Pietro G, Fasolino A, Galosi E, Leone C, Cruccu G, Marinelli L, Leandri M, Truini A. The new micropatterned interdigitated electrode for selective assessment of the nociceptive system. Eur J Pain 2020; 24:956-966. [DOI: 10.1002/ejp.1545] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 01/20/2020] [Accepted: 02/11/2020] [Indexed: 11/08/2022]
Affiliation(s)
| | | | - Silvia La Cesa
- Department of Human Neuroscience Sapienza University Rome Italy
| | | | | | - Eleonora Galosi
- Department of Human Neuroscience Sapienza University Rome Italy
| | - Caterina Leone
- Department of Human Neuroscience Sapienza University Rome Italy
| | - Giorgio Cruccu
- Department of Human Neuroscience Sapienza University Rome Italy
| | - Lucio Marinelli
- Department of Neuroscience Genetics, Maternal and Child Health (DINOGMI) University of Genova Genova Italy
- Department of Neuroscience Ospedale Policlinico San Martino Genova Italy
| | - Massimo Leandri
- Department of Neuroscience Genetics, Maternal and Child Health (DINOGMI) University of Genova Genova Italy
| | - Andrea Truini
- Department of Human Neuroscience Sapienza University Rome Italy
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Gentile E, Brunetti A, Ricci K, Delussi M, Bevilacqua V, de Tommaso M. Mutual interaction between motor cortex activation and pain in fibromyalgia: EEG-fNIRS study. PLoS One 2020; 15:e0228158. [PMID: 31971993 PMCID: PMC6977766 DOI: 10.1371/journal.pone.0228158] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 01/08/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Experimental and clinical studies suggested an analgesic effect on chronic pain by motor cortex activation. The present study explored the complex mechanisms of interaction between motor and pain during performing the slow and fast finger tapping task alone and in concomitant with nociceptive laser stimulation. METHOD The participants were 38 patients with fibromyalgia (FM) and 21 healthy subjects. We used a simultaneous multimodal method of laser-evoked potentials and functional near-infrared spectroscopy to investigate metabolic and electrical changes during the finger tapping task and concomitant noxious laser stimulation. Functional near-infrared spectroscopy is a portable and optical method to detect cortical metabolic changes. Laser-evoked potentials are a suitable tool to study the nociceptive pathways function. RESULTS We found a reduced tone of cortical motor areas in patients with FM compared to controls, especially during the fast finger tapping task. FM patients presented a slow motor performance in all the experimental conditions, requesting rapid movements. The amplitude of laser evoked potentials was different between patients and controls, in each experimental condition, as patients showed smaller evoked responses compared to controls. Concurrent phasic pain stimulation had a low effect on motor cortex metabolism in both groups nor motor activity changed laser evoked responses in a relevant way. There were no correlations between Functional Near-Infrared Spectroscopy (FNIRS) and clinical features in FM patients. CONCLUSION Our findings indicated that a low tone of motor cortex activation could be an intrinsic feature in FM and generate a scarce modulation on pain condition. A simple and repetitive movement such as that of the finger tapping task seems inefficacious in modulating cortical responses to pain both in patients and controls. The complex mechanisms of interaction between networks involved in pain control and motor function require further studies for the important role they play in structuring rehabilitation strategies.
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Affiliation(s)
- Eleonora Gentile
- Applied Neurophysiology and Pain Unit, SMBNOS Department, Bari Aldo Moro University, Polyclinic General Hospital, Bari, Italy
| | - Antonio Brunetti
- Department of Electrical and Information Engineering, Polytecnic University of Bari, Bari, Italy
| | - Katia Ricci
- Applied Neurophysiology and Pain Unit, SMBNOS Department, Bari Aldo Moro University, Polyclinic General Hospital, Bari, Italy
| | - Marianna Delussi
- Applied Neurophysiology and Pain Unit, SMBNOS Department, Bari Aldo Moro University, Polyclinic General Hospital, Bari, Italy
| | - Vitoantonio Bevilacqua
- Department of Electrical and Information Engineering, Polytecnic University of Bari, Bari, Italy
| | - Marina de Tommaso
- Applied Neurophysiology and Pain Unit, SMBNOS Department, Bari Aldo Moro University, Polyclinic General Hospital, Bari, Italy
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45
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de Tommaso M, Ricci K, Conca G, Vecchio E, Delussi M, Invitto S. Empathy for pain in fibromyalgia patients: An EEG study. Int J Psychophysiol 2019; 146:43-53. [DOI: 10.1016/j.ijpsycho.2019.09.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 08/16/2019] [Accepted: 09/24/2019] [Indexed: 01/01/2023]
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46
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Gozani SN. Remote Analgesic Effects Of Conventional Transcutaneous Electrical Nerve Stimulation: A Scientific And Clinical Review With A Focus On Chronic Pain. J Pain Res 2019; 12:3185-3201. [PMID: 31819603 PMCID: PMC6885653 DOI: 10.2147/jpr.s226600] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 11/02/2019] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Transcutaneous electrical nerve stimulation (TENS) is a safe, noninvasive treatment for chronic pain that can be self-administered. Conventional TENS involves stimulation of peripheral sensory nerves at a strong, non-painful level. Following the original gate-control theory of pain, stimulation is typically near the target pain. As another option, remote stimulation may also be effective and offers potential advantages. OBJECTIVE This narrative review examines mechanisms underlying the remote analgesic effects of conventional TENS and appraises the clinical evidence. METHODS A literature search for English-language articles was performed on PubMed. Keywords included terms related to the location of TENS . Citations from primary references and textbooks were examined for additional articles. RESULTS Over 30 studies reported remote analgesic effects of conventional TENS. The evidence included studies using animal models of pain, experimental pain in humans, and clinical studies in subjects with chronic pain. Three types of remote analgesia were identified: at the contralateral homologous site, at sites distant from stimulation but innervated by overlapping spinal segments, and at unrelated extrasegmental sites. CONCLUSION There is scientific and clinical evidence that conventional TENS has remote analgesic effects. This may occur through modulation of pain processing at the level of the dorsal horn, in brainstem centers mediating descending inhibition, and within the pain matrix. A broadening of perspectives on how conventional TENS produces analgesia may encourage researchers, clinicians, and medical-device manufacturers to develop novel ways of using this safe, cost-effective neuromodulation technique for chronic pain.
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47
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Van Assche DCF, Plaghki L, Masquelier E, Hatem SM. Fibromyalgia syndrome—A laser‐evoked potentials study unsupportive of small nerve fibre involvement. Eur J Pain 2019; 24:448-456. [DOI: 10.1002/ejp.1501] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 10/28/2019] [Accepted: 10/29/2019] [Indexed: 02/02/2023]
Affiliation(s)
| | - Leon Plaghki
- Institute of Neuroscience Université catholique de Louvain Brussels Belgium
| | - Etienne Masquelier
- Institute of Neuroscience Université catholique de Louvain Brussels Belgium
- Multidisciplinary Pain Center CHU UCL Namur, site Godinne Yvoir Belgium
| | - Samar M. Hatem
- Physical Medicine and Rehabilitation Brugmann University Hospital Brussels Belgium
- Institute of Neuroscience Université catholique de Louvain Brussels Belgium
- Faculty of Medicine and Pharmacy Vrije Universiteit Brussel Brussels Belgium
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48
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Liang M, Su Q, Mouraux A, Iannetti GD. Spatial Patterns of Brain Activity Preferentially Reflecting Transient Pain and Stimulus Intensity. Cereb Cortex 2019; 29:2211-2227. [PMID: 30844052 PMCID: PMC6458907 DOI: 10.1093/cercor/bhz026] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 01/29/2019] [Indexed: 01/19/2023] Open
Abstract
How pain emerges in the human brain remains an unresolved question. Neuroimaging studies have suggested that several brain areas subserve pain perception because their activation correlates with perceived pain intensity. However, painful stimuli are often intense and highly salient; therefore, using both intensity- and saliency-matched control stimuli is crucial to isolate pain-selective brain responses. Here, we used these intensity/saliency-matched painful and non-painful stimuli to test whether pain-selective information can be isolated in the functional magnetic resonance imaging responses elicited by painful stimuli. Using two independent datasets, multivariate pattern analysis was able to isolate features distinguishing the responses triggered by (1) intensity/saliency-matched painful versus non-painful stimuli, and (2) high versus low-intensity/saliency stimuli regardless of whether they elicit pain. This indicates that neural activity in the so-called "pain matrix" is functionally heterogeneous, and part of it carries information related to both painfulness and intensity/saliency. The response features distinguishing these aspects are spatially distributed and cannot be ascribed to specific brain structures.
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Affiliation(s)
- M Liang
- School of Medical Imaging and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University, Tianjin, China
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Q Su
- School of Medical Imaging and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University, Tianjin, China
| | - A Mouraux
- Institute of Neuroscience (IoNS), Université catholique de Louvain, Brussels, Belgium
| | - G D Iannetti
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
- Neuroscience and Behaviour Laboratory, Istituto Italiano di Tecnologia, Rome, Italy
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49
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Filbrich L, Blandiaux S, Manfron L, Farnè A, De Keyser R, Legrain V. Unimodal and crossmodal extinction of nociceptive stimuli in healthy volunteers. Behav Brain Res 2019; 362:114-121. [PMID: 30630019 DOI: 10.1016/j.bbr.2019.01.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 12/28/2018] [Accepted: 01/06/2019] [Indexed: 11/25/2022]
Abstract
Nociception, the physiological mechanisms specifically processing information about noxious and potentially painful stimuli, has the double function to warn about potential body damages (interoception) and about the cause of such potential damages (exteroception). The exteroceptive function is thought to rely on multisensory integration between somatic and extra-somatic stimuli, provided that extra-somatic stimuli occur near the stimulated body area. To corroborate this hypothesis, we succeeded to show in healthy volunteers that the perception of nociceptive stimuli applied on one hand can be extinguished, as compared to single presentation, by the simultaneous application of nociceptive stimuli on the opposite hand, as well as by the presentation of visual stimuli near the opposite hand. On the contrary, visual stimuli presented near the same stimulated hand facilitated the perception of nociceptive stimuli. This nociceptive extinction phenomenon indicates that the perception of noxious events does not merely rely on the specific activation of the nociceptive system, but also depends on other sensory experiences about the body and the space around it.
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Affiliation(s)
- Lieve Filbrich
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium; Psychological Sciences Research Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Séverine Blandiaux
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Louise Manfron
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium; Psychological Sciences Research Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Alessandro Farnè
- ImpAct team, Lyon Neuroscience Research Center, INSERM U1028, CNRS UMR5292, Lyon, France
| | - Roxane De Keyser
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Valéry Legrain
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium; Psychological Sciences Research Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium.
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50
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Rosner J, Rinert J, Ernst M, Curt A, Hubli M. Cold evoked potentials: Acquisition from cervical dermatomes. Neurophysiol Clin 2019; 49:49-57. [DOI: 10.1016/j.neucli.2018.11.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 11/26/2018] [Accepted: 11/26/2018] [Indexed: 01/06/2023] Open
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