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In A, Strohman A, Payne B, Legon W. Low-intensity focused ultrasound to the posterior insula reduces temporal summation of pain. Brain Stimul 2024; 17:911-924. [PMID: 39089647 DOI: 10.1016/j.brs.2024.07.020] [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: 01/13/2024] [Revised: 07/24/2024] [Accepted: 07/29/2024] [Indexed: 08/04/2024] Open
Abstract
BACKGROUND The insula and dorsal anterior cingulate cortex (dACC) are core brain regions involved in pain processing and central sensitization, a shared mechanism across various chronic pain conditions. Methods to modulate these regions may serve to reduce central sensitization, though it is unclear which target may be most efficacious for different measures of central sensitization. OBJECTIVE/HYPOTHESIS Investigate the effect of low-intensity focused ultrasound (LIFU) to the anterior insula (AI), posterior insula (PI), or dACC on conditioned pain modulation (CPM) and temporal summation of pain (TSP). METHODS N = 16 volunteers underwent TSP and CPM pain tasks pre/post a 10 min LIFU intervention to either the AI, PI, dACC or Sham stimulation. Pain ratings were collected pre/post LIFU. RESULTS Only LIFU to the PI significantly attenuated pain ratings during the TSP protocol. No effects were found for the CPM task for any of the LIFU targets. LIFU pressure modulated group means but did not affect overall group differences. CONCLUSIONS LIFU to the PI reduced temporal summation of pain. This may, in part, be due to dosing (pressure) of LIFU. Inhibition of the PI with LIFU may be a future potential therapy in chronic pain populations demonstrating central sensitization. The minimal effective dose of LIFU for efficacious neuromodulation will help to translate LIFU for therapeutic options.
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Affiliation(s)
- Alexander In
- Virginia Tech Carilion School of Medicine, Roanoke, VA, 24016, USA
| | - Andrew Strohman
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, 24016, USA; Virginia Tech Carilion School of Medicine, Roanoke, VA, 24016, USA; Graduate Program in Translational Biology, Medicine, and Health, Virginia Polytechnic Institute and State University, Roanoke, VA, 24016, USA
| | - Brighton Payne
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, 24016, USA
| | - Wynn Legon
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, 24016, USA; Virginia Tech Carilion School of Medicine, Roanoke, VA, 24016, USA; Center for Human Neuroscience Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, 24016, USA; Center for Health Behaviors Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, 24016, USA; School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24016, USA; Graduate Program in Translational Biology, Medicine, and Health, Virginia Polytechnic Institute and State University, Roanoke, VA, 24016, USA; Department of Neurosurgery, Carilion Clinic, Roanoke, VA, 24016, USA.
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Carrillo-de-la-Peña MT, Fernandes C, Castro C, Medeiros R. Validity of central pain processing biomarkers for predicting the occurrence of oncological chronic pain: a study protocol. BMC Cancer 2024; 24:705. [PMID: 38849731 PMCID: PMC11161916 DOI: 10.1186/s12885-024-12455-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Accepted: 05/30/2024] [Indexed: 06/09/2024] Open
Abstract
BACKGROUND Despite recent improvements in cancer detection and survival rates, managing cancer-related pain remains a significant challenge. Compared to neuropathic and inflammatory pain conditions, cancer pain mechanisms are poorly understood, despite pain being one of the most feared symptoms by cancer patients and significantly impairing their quality of life, daily activities, and social interactions. The objective of this work was to select a panel of biomarkers of central pain processing and modulation and assess their ability to predict chronic pain in patients with cancer using predictive artificial intelligence (AI) algorithms. METHODS We will perform a prospective longitudinal cohort, multicentric study involving 450 patients with a recent cancer diagnosis. These patients will undergo an in-person assessment at three different time points: pretreatment, 6 months, and 12 months after the first visit. All patients will be assessed through demographic and clinical questionnaires and self-report measures, quantitative sensory testing (QST), and electroencephalography (EEG) evaluations. We will select the variables that best predict the future occurrence of pain using a comprehensive approach that includes clinical, psychosocial, and neurophysiological variables. DISCUSSION This study aimed to provide evidence regarding the links between poor pain modulation mechanisms at precancer treatment in patients who will later develop chronic pain and to clarify the role of treatment modality (modulated by age, sex and type of cancer) on pain. As a final output, we expect to develop a predictive tool based on AI that can contribute to the anticipation of the future occurrence of pain and help in therapeutic decision making.
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Affiliation(s)
- M T Carrillo-de-la-Peña
- Brain and Pain (BaP) Lab, Departamento de Psicoloxía Clínica y Psicobioloxía, Facultade de Psicoloxia, Universidade de Santiago de Compostela, Campus Vida, Santiago de Compostela, A Coruña, 15782, Spain
| | - C Fernandes
- Faculty of Human and Social Sciences, University Fernando Pessoa, Praça 9 de Abril, 349, Porto, 4249-004, Portugal
- Faculty of Psychology and Education Sciences, Laboratory of Neuropsychophysiology, University of Porto, Rua Alfredo Allen, Porto, 4200-135, Portugal
- Molecular Oncology and Viral Pathology Group, Research Center of IPO (CI-IPOP) & RISE@CI-IPOP (Health Research Network), Portuguese Oncology Institute of Porto (IPO Porto)/Porto Comprehensive Cancer Center (Porto. CCC), R. Dr. António Bernardino de Almeida 865, Porto, 4200-072, Portugal
| | - C Castro
- Molecular Oncology and Viral Pathology Group, Research Center of IPO (CI-IPOP) & RISE@CI-IPOP (Health Research Network), Portuguese Oncology Institute of Porto (IPO Porto)/Porto Comprehensive Cancer Center (Porto. CCC), R. Dr. António Bernardino de Almeida 865, Porto, 4200-072, Portugal.
- School of Health, Polytechnic Institute of Porto, Rua Dr. António Bernardino de Almeida, 400, Porto, 4200-072, Portugal.
- Unit of Anatomy, Department of Biomedicine, Faculty of Medicine, University of Porto, Alameda Prof. Hernâni Monteiro, Porto, 4200-319, Portugal.
| | - R Medeiros
- Molecular Oncology and Viral Pathology Group, Research Center of IPO (CI-IPOP) & RISE@CI-IPOP (Health Research Network), Portuguese Oncology Institute of Porto (IPO Porto)/Porto Comprehensive Cancer Center (Porto. CCC), R. Dr. António Bernardino de Almeida 865, Porto, 4200-072, Portugal
- Faculty of Medicine, University of Porto, Alameda Prof. Hernâni Monteiro, Porto, 4200-319, Portugal
- Abel Salazar Institute of Biomedical Sciences (ICBAS), University of Porto, R. Jorge de Viterbo Ferreira 228, Porto, 4050-313, Portugal
- Virology Service, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Rua Dr. António Bernardino de Almeida, 865, 4200-072, Portugal
- Biomedical Research Center (CEBIMED), Faculty of Health Sciences of Fernando Pessoa University, Praça 9 de Abril, 349, Porto, 4249-004, Portugal
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Kersebaum D, Sendel M, Lassen J, Fabig SC, Forstenpointner J, Reimer M, Canaan-Kühl S, Gaedeke J, Rehm S, Gierthmühlen J, Baron R, Hüllemann P. Cold-evoked potentials in Fabry disease and polyneuropathy. FRONTIERS IN PAIN RESEARCH 2024; 5:1352711. [PMID: 38812855 PMCID: PMC11133603 DOI: 10.3389/fpain.2024.1352711] [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: 12/08/2023] [Accepted: 04/02/2024] [Indexed: 05/31/2024] Open
Abstract
Background Fabry disease (FD) causes cold-evoked pain and impaired cold perception through small fiber damage, which also occurs in polyneuropathies (PNP) of other origins. The integrity of thinly myelinated fibers and the spinothalamic tract is assessable by cold-evoked potentials (CEPs). In this study, we aimed to assess the clinical value of CEP by investigating its associations with pain, autonomic measures, sensory loss, and neuropathic signs. Methods CEPs were examined at the hand and foot dorsum of patients with FD (n = 16) and PNP (n = 21) and healthy controls (n = 23). Sensory phenotyping was performed using quantitative sensory testing (QST). The painDETECT questionnaire (PDQ), FabryScan, and measures for the autonomic nervous system were applied. Group comparisons and correlation analyses were performed. Results CEPs of 87.5% of the FD and 85.7% of the PNP patients were eligible for statistical analysis. In all patients combined, CEP data correlated significantly with cold detection loss, PDQ items, pain, and autonomic measures. Abnormal CEP latency in FD patients was associated with an abnormal heart frequency variability item (r = -0.684; adjusted p = 0.04). In PNP patients, CEP latency correlated significantly with PDQ items, and CEP amplitude correlated with autonomic measures (r = 0.688, adjusted p = 0.008; r = 0.619, adjusted p = 0.024). Furthermore, mechanical pain thresholds differed significantly between FD (gain range) and PNP patients (loss range) (p = 0.01). Conclusions Abnormal CEPs were associated with current pain, neuropathic signs and symptoms, and an abnormal function of the autonomic nervous system. The latter has not been mirrored by QST parameters. Therefore, CEPs appear to deliver a wider spectrum of information on the sensory nervous system than QST alone.
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Affiliation(s)
- Dilara Kersebaum
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Kiel, Germany
- Schön Clinic Rendsburg, Department of Psychiatry, Psychotherapy and Psychosomatics, Rendsburg, Germany
| | - Manon Sendel
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Josephine Lassen
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Sophie-Charlotte Fabig
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Julia Forstenpointner
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Maren Reimer
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Sima Canaan-Kühl
- Division of Nephrology, Department of Medicine, Charité, Berlin, Germany
| | - Jens Gaedeke
- Division of Nephrology, Department of Medicine, Charité, Berlin, Germany
| | - Stefanie Rehm
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Janne Gierthmühlen
- Interdisciplinary Pain and Palliative Care Division, Department of Anesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Campus Kiel, Germany
| | - Ralf Baron
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Philipp Hüllemann
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Kiel, Germany
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Perchet C, Hagiwara K, Salameh C, Garcia-Larrea L. Cold-evoked potentials in clinical practice: A head-to-head contrast with laser-evoked responses. Eur J Pain 2023; 27:1006-1022. [PMID: 37278358 DOI: 10.1002/ejp.2142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 05/17/2023] [Accepted: 05/21/2023] [Indexed: 06/07/2023]
Abstract
BACKGROUND Innocuous cooling of the skin activates cold-specific Aδ fibres, and hence, the recording of cold-evoked potentials (CEPs) may improve the objective assessment of human thermo-nociceptive function. While the feasibility of CEP recordings in healthy humans has been reported, their reliability and diagnostic use in clinical conditions have not been documented. METHODS Here, we report the results of CEP recordings in 60 consecutive patients with suspected neuropathic pain, compared with laser-evoked potentials (LEPs) which are the gold standard for thermo-algesic instrumental assessment. RESULTS CEP recording was a well-tolerated procedure, with only ~15 min of surplus in exam duration. The reproducibility and signal-to-noise ratio of CEPs were lower than those of LEPs, in particular for distal lower limbs (LLs). While laser responses were interpretable in all patients, CEPs interpretation was inconclusive in 5/60 because of artefacts or lack of response on the unaffected side. Both techniques yielded concordant results in 73% of the patients. In 12 patients, CEPs yielded abnormal values while LEPs remained within normal limits; 3 of these patients had clinical symptoms limited to cold sensations, including cold-heat transformation. CONCLUSIONS CEPs appear as a useful technique for exploring pain/temperature systems. Advantages are low cost of equipment and innocuity. Disadvantages are low signal-to-noise ratio for LL stimulation, and sensitivity to fatigue/habituation. Joint recording of CEPs and LEPs can increase the sensitivity of neurophysiological techniques to thin fibre- spinothalamic lesions, in particular, when abnormalities of cold perception predominate. SIGNIFICANCE Recording of cold-evoked potentials is a well-tolerated, inexpensive and easy-to-use procedure that can be helpful in the diagnosis of abnormalities in the thin fibre- spinothalamic pathways. Supplementing LEPs with CEPs allows consolidating the diagnosis and, for some patients suffering from symptoms limited only to cold, CEPs but not LEPs may allow the diagnosis of thin fibre pathology. Optimal CEP recording conditions are important to overcome the low signal-to-noise ratio and habituation phenomena, which are less favourable than with LEPs.
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Affiliation(s)
- Caroline Perchet
- Université Claude Bernard Lyon 1, CNRS, INSERM, Centre de Recherche en Neurosciences de Lyon CRNL U1028, UMR5292, NEUROPAIN, Bron, France
| | - Koichi Hagiwara
- Université Claude Bernard Lyon 1, CNRS, INSERM, Centre de Recherche en Neurosciences de Lyon CRNL U1028, UMR5292, NEUROPAIN, Bron, France
- Fukuoka International University of Health and Welfare, Fukuoka, Japan
| | - Charbel Salameh
- Université Claude Bernard Lyon 1, CNRS, INSERM, Centre de Recherche en Neurosciences de Lyon CRNL U1028, UMR5292, NEUROPAIN, Bron, France
| | - Luis Garcia-Larrea
- Université Claude Bernard Lyon 1, CNRS, INSERM, Centre de Recherche en Neurosciences de Lyon CRNL U1028, UMR5292, NEUROPAIN, Bron, France
- Centre D'évaluation et de Traitement de la Douleur, Hôpital Neurologique, Lyon, France
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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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Mulders D, Seymour B, Mouraux A, Mancini F. Confidence of probabilistic predictions modulates the cortical response to pain. Proc Natl Acad Sci U S A 2023; 120:e2212252120. [PMID: 36669115 PMCID: PMC9942789 DOI: 10.1073/pnas.2212252120] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 11/21/2022] [Indexed: 01/21/2023] Open
Abstract
Pain typically evolves over time, and the brain needs to learn this temporal evolution to predict how pain is likely to change in the future and orient behavior. This process is termed temporal statistical learning (TSL). Recently, it has been shown that TSL for pain sequences can be achieved using optimal Bayesian inference, which is encoded in somatosensory processing regions. Here, we investigate whether the confidence of these probabilistic predictions modulates the EEG response to noxious stimuli, using a TSL task. Confidence measures the uncertainty about the probabilistic prediction, irrespective of its actual outcome. Bayesian models dictate that the confidence about probabilistic predictions should be integrated with incoming inputs and weight learning, such that it modulates the early components of the EEG responses to noxious stimuli, and this should be captured by a negative correlation: when confidence is higher, the early neural responses are smaller as the brain relies more on expectations/predictions and less on sensory inputs (and vice versa). We show that participants were able to predict the sequence transition probabilities using Bayesian inference, with some forgetting. Then, we find that the confidence of these probabilistic predictions was negatively associated with the amplitude of the N2 and P2 components of the vertex potential: the more confident were participants about their predictions, the smaller the vertex potential. These results confirm key predictions of a Bayesian learning model and clarify the functional significance of the early EEG responses to nociceptive stimuli, as being implicated in confidence-weighted statistical learning.
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Affiliation(s)
- Dounia Mulders
- Computational and Biological Learning Unit, Department of Engineering, University of Cambridge, CambridgeCB2 1PZ, UK
- Institute of Neuroscience, UCLouvain, 1200 Woluwe-Saint-Lambert, Belgium
- Institute for Information and Communication Technologies, Electronics and Applied Mathematics, UCLouvain, 1348 Louvain-la-NeuveBelgium
- Department of Brain and Cognitive Sciences and McGovern Institute, Massachusetts Institute of Technology, MA02139
| | - Ben Seymour
- Wellcome Centre for Integrative Neuroimaging, John Radcliffe Hospital, Headington, OxfordOX3 9DU, UK
- Center for Information and Neural Networks (CiNet), Osaka565-0871, Japan
| | - André Mouraux
- Institute of Neuroscience, UCLouvain, 1200 Woluwe-Saint-Lambert, Belgium
| | - Flavia Mancini
- Computational and Biological Learning Unit, Department of Engineering, University of Cambridge, CambridgeCB2 1PZ, UK
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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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Courtin AS, Mouraux A. Combining Topical Agonists With the Recording of Event-Related Brain Potentials to Probe the Functional Involvement of TRPM8, TRPA1 and TRPV1 in Heat and Cold Transduction in the Human Skin. THE JOURNAL OF PAIN 2022; 23:754-771. [PMID: 34863944 DOI: 10.1016/j.jpain.2021.11.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 11/04/2021] [Accepted: 11/18/2021] [Indexed: 06/13/2023]
Abstract
TRP channels play a central role in the transduction of thermal and nociceptive stimuli by free nerve endings. Most of the research on these channels has been conducted in vitro or in vivo in nonhuman animals and translation of these results to humans must account for potential experimental biases and interspecific differences. This study aimed at evaluating the involvement of TRPM8, TRPA1 and TRPV1 channels in the transduction of heat and cold stimuli by the human thermonociceptive system. For this purpose, we evaluated the effects of topical agonists of these 3 channels (menthol, cinnamaldehyde and capsaicin) on the event-related brain potentials (ERPs) elicited by phasic thermal stimuli (target temperatures: 10°C, 42°C, and 60°C) selected to activate cold Aδ thermoreceptors, warm sensitive C thermoreceptors and heat sensitive Aδ polymodal nociceptors. Sixty-four participants were recruited, 16 allocated to each agonist solution group (20% menthol, 10% cinnamaldehyde, .025% capsaicin and 1% capsaicin). Participants were treated sequentially with the active solution on one forearm and vehicle only on the other forearm for 20 minutes. Menthol decreased the amplitude and increased the latency of cold and heat ERPs. Cinnamic aldehyde decreased the amplitude and increased the latency of heat but not cold ERPs. Capsaicin decreased the amplitude and increased the latency of heat ERPs and decreased the amplitude of the N2P2 complex of the cold ERPs without affecting the earlier N1 wave or the latencies of the peaks. These findings are compatible with previous evidence indicating that TRPM8 is involved in innocuous cold transduction and that TRPV1 and TRPA1 are involved in noxious heat transduction in humans. PERSPECTIVE: By chemically modulating TRPM8, TRPA1 and TRPV1 reactivity (key molecules in the transduction of temperature) and assessing how this affected EEG responses to the activation of cold thermoreceptors and heat nociceptors, we aimed at confirming the role of these channels in a functional healthy human model.
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Affiliation(s)
- Arthur S Courtin
- Institute of NeuroScience, Université catholique de Louvain, Brussels, Belgium.
| | - André Mouraux
- Institute of NeuroScience, Université catholique de Louvain, Brussels, Belgium
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Cold evoked potentials elicited by rapid cooling of the skin in young and elderly healthy individuals. Sci Rep 2022; 12:4137. [PMID: 35264694 PMCID: PMC8907280 DOI: 10.1038/s41598-022-07967-x] [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: 10/19/2021] [Accepted: 02/21/2022] [Indexed: 11/08/2022] Open
Abstract
Cold-evoked potentials (CEPs) constitute a novel electrophysiological tool to assess cold-specific alterations in somatosensory function. As an important step towards the clinical implementation of CEPs as a diagnostic tool, we evaluated the feasibility and reliability of CEPs in response to rapid cooling of the skin (-300 °C/s) and different stimulation sites in young and elderly healthy individuals. Time-locked electroencephalographic responses were recorded from at vertex in fifteen young (20-40 years) and sixteen elderly (50-70 years), individuals in response to 15 rapid cold stimuli (-300 °C/s) applied to the skin of the hand dorsum, palm, and foot dorsum. High CEP proportions were shown for young individuals at all sites (hand dorsum/palm: 100% and foot: 79%) and elderly individuals after stimulation of the hand dorsum (81%) and palm (63%), but not the foot (44%). Depending on the age group and stimulation site, test-retest reliability was "poor" to "substantial" for N2P2 amplitudes and N2 latencies. Rapid cooling of the skin enables the recording of reliable CEPs in young individuals. In elderly individuals, CEP recordings were only robust after stimulation of the hand, but particularly challenging after stimulation of the foot. Further improvements in stimulation paradigms are warranted to introduce CEPs for clinical diagnostics.
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Lithfous S, Trocmet L, Pebayle T, Després O, Dufour A. Investigating cold Aδ fibers in the 0-40 °C temperature range: A quantitative sensory testing and evoked potentials study. Clin Neurophysiol 2021; 134:81-87. [PMID: 34991016 DOI: 10.1016/j.clinph.2021.11.076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 11/08/2021] [Accepted: 11/14/2021] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To evaluate the activity of cold Aδ-type fibers to thermal stimuli above human skin temperature (i.e., >32 °C). METHODS Twenty young adults aged 20-24 years participated in this study. The cold-detection threshold was measured from a basal temperature of 40 °C using an adaptive staircase method with high-speed cooling ramps (170 °C/s). A total of 150 stimulations at 36 °C, 32 °C, 28 °C, 24 °C, 20 °C, 16 °C, 12 °C, 8 °C, 4 °C and 0 °C (15 each) were performed. After each stimulation, subjects estimated the intensity of cold sensation using a visual analog scale, and evoked potentials were recorded. RESULTS The average cold-detection threshold was 35 °C (SD = 1.8). Regardless of the stimulation temperature, subjects reported a cooling sensation. Interestingly, reported increments in sensation were prominent for stimulation temperatures between 32 °C and 20 °C, but below this latter temperature sensations varied only very slightly. Evoked potential recordings revealed that decreasing temperature stimuli from a baseline of 40 °C induced a previously unreported N2P2 component with a mean N2 peak latency of 275 ms (SD = 13.1). The peak-to-peak amplitude of the N2P2 complex increased as the intensity of the cooling stimulation increased, exhibiting a profile comparable to subject-perceived intensity, namely, a major increase up to 20 °C, followed by a plateau to 0 °C. CONCLUSIONS The cool sensations reported by subjects were likely conveyed by Aδ fibers rather than by slow-conducting C fibers. Moreover, our rapid stimulation technique starting from a high temperature (40 °C) was capable of a) generating cold sensations at stimulation temperatures between 36 °C and 32 °C, and b) revealing the optimal activation range of Aδ fibers (20 °C-28 °C). Any decrease in temperature below this range did not result in a significant increase in sensation and thus probably did not evoke a significant increase in Aδ fiber activity. SIGNIFICANCE The regular assessment of cold sensation in peripheral neuropathies (i.e., with temperatures below 32 °C), could be completed by investigating cold-detection thresholds at temperatures ranging from 40 °C to 32 °C. Indeed, the absolute threshold of cold perception appears to start at 35 °C. Changes in the activation threshold of cold fibers were more easily detectable at this level.
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Affiliation(s)
- Ségolène Lithfous
- Laboratoire de Neurosciences Cognitives et Adaptatives, Université de Strasbourg, CNRS, UMR 7364 LNCA, 12 rue Goethe, 67000 Strasbourg, France
| | - Louise Trocmet
- Laboratoire de Neurosciences Cognitives et Adaptatives, Université de Strasbourg, CNRS, UMR 7364 LNCA, 12 rue Goethe, 67000 Strasbourg, France
| | - Thierry Pebayle
- Centre d'Investigations Neurocognitives et Neurophysiologiques, Université de Strasbourg, CNRS, UMS 3489 CI2N, 21 rue Becquerel, 67087 Strasbourg, France
| | - Olivier Després
- Laboratoire de Neurosciences Cognitives et Adaptatives, Université de Strasbourg, CNRS, UMR 7364 LNCA, 12 rue Goethe, 67000 Strasbourg, France
| | - André Dufour
- Laboratoire de Neurosciences Cognitives et Adaptatives, Université de Strasbourg, CNRS, UMR 7364 LNCA, 12 rue Goethe, 67000 Strasbourg, France; Centre d'Investigations Neurocognitives et Neurophysiologiques, Université de Strasbourg, CNRS, UMS 3489 CI2N, 21 rue Becquerel, 67087 Strasbourg, France.
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11
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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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Wu CM, Lee MH, Wang WY, Cai ZY. Acute Effects of Intermittent Foot Cooling on 1 RM Leg Press Strength in Resistance-Trained Men: A Pilot Study. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18189594. [PMID: 34574518 PMCID: PMC8465553 DOI: 10.3390/ijerph18189594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/06/2021] [Accepted: 09/10/2021] [Indexed: 11/16/2022]
Abstract
Inter-set peripheral cooling can improve high-intensity resistance exercise performance. However, whether foot cooling (FC) would increase 1 repetition maximum (RM) lower-limb strength is unclear. This study investigated the effect of intermittent FC on 1 RM leg press strength. Ten recreational male lifters performed three attempts of 1 RM leg press with FC or non-cooling (NC) in a repeated-measures crossover design separated by 5 days. FC was applied by foot immersion in 10 °C water for 2.5 min before each attempt. During the 1 RM test, various physiological measures were recorded. The results showed that FC elicited higher 1 RM leg press strength (Δ [95% CI]; Cohen's d effect size [ES]; 13.6 [7.6-19.5] kg; ES = 1.631) and electromyography values in vastus lateralis (57.7 [8.1-107.4] μV; ES = 0.831) and gastrocnemius (15.1 [-3.1-33.2] μV; ES = 0.593) than in NC. Higher arousal levels (felt arousal scale) were found in FC (0.6 [0.1-1.2]; ES = 0.457) than in NC. In conclusion, the preliminary findings, although limited, suggest intermittent FC has a potential ergogenic role for recreational athletes to enhance maximal lower-limb strength and may partly benefit strength-based competition events.
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Affiliation(s)
- Chih-Min Wu
- Department of Leisure and Sports Management, Cheng Shiu University, Kaohsiung 83300, Taiwan;
| | - Mei-Hsien Lee
- Department of Mathematics, University of Taipei, Taipei 100234, Taiwan;
| | - Wen-Yi Wang
- Graduate Institute of Sports Pedagogy, University of Taipei, Taipei 111036, Taiwan;
| | - Zong-Yan Cai
- Center for Physical and Health Education, SiWan College, National Sun Yat-Sen University, Kaohsiung 804201, Taiwan
- Correspondence: ; Tel.: +886-7-5252-000 (ext. 5872)
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Transcutaneous auricular VNS applied to experimental pain: A paired behavioral and EEG study using thermonociceptive CO2 laser. PLoS One 2021; 16:e0254480. [PMID: 34252124 PMCID: PMC8274876 DOI: 10.1371/journal.pone.0254480] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 06/24/2021] [Indexed: 11/19/2022] Open
Abstract
Background Transcutaneous auricular Vagal Nerve Stimulation (taVNS) is a non-invasive neurostimulation technique with potential analgesic effects. Several studies based on subjective behavioral responses suggest that taVNS modulates nociception differently with either pro-nociceptive or anti-nociceptive effects. Objective This study aimed to characterize how taVNS alters pain perception, by investigating its effects on event-related potentials (ERPs) elicited by different types of spinothalamic and lemniscal somatosensory stimuli, combined with quantitative sensory testing (detection threshold and intensity ratings). Methods We performed 3 experiments designed to study the time-dependent effects of taVNS and compare with standard cervical VNS (cVNS). In Experiment 1, we assessed the effects of taVNS after 3 hours of stimulation. In Experiment 2, we focused on the immediate effects of the duty cycle (OFF vs. ON phases). Experiments 1 and 2 included 22 and 15 healthy participants respectively. Both experiments consisted of a 2-day cross-over protocol, in which subjects received taVNS and sham stimulation sequentially. In addition, subjects received a set of nociceptive (thermonociceptive CO2 laser, mechanical pinprick) and non-nociceptive (vibrotactile, cool) stimuli, for which we recorded detection thresholds, intensity of perception and ERPs. Finally, in Experiment 3, we tested 13 epileptic patients with an implanted cVNS by comparing OFF vs. ON cycles, using a similar experimental procedure. Results Neither taVNS nor cVNS appeared to modulate the cerebral and behavioral aspects of somatosensory perception. Conclusion The potential effect of taVNS on nociception requires a cautious interpretation, as we found no objective change in behavioral and cerebral responses to spinothalamic and lemniscal somatosensory stimulations.
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14
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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: 14] [Impact Index Per Article: 4.7] [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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15
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Lithfous S, Després O, Pebayle T, Casadio C, Dufour A. Accurate Determination of the Cold Detection Threshold with High-Speed Cooling of the Skin. PAIN MEDICINE 2020; 21:3428-3436. [PMID: 33011804 DOI: 10.1093/pm/pnaa246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE This study used high-speed cooling of the skin and exact control of stimulus duration to measure the cold detection threshold in healthy participants. The objective was to compare the method of limits, in which the temperature is slowly and gradually increased/decreased until the subject perceives the stimulation, and the method of levels, in which the subject must detect brief thermal stimulations close to the threshold of perception. METHODS Twenty healthy volunteers (nine women, 11 men) aged 20-30 years participated in the study. The method of limits and method of levels were performed in all subjects in a counterbalanced order. Four cold detection thresholds were measured with the method of levels, with a temperature ramp of 300°C/sec and stimulus durations of 50 ms, 100 ms, 300 ms, and 500 ms. Three thresholds were measured with the method of limits, with temperature ramps of 1°C/sec, 2°C/sec, and 4°C/sec. RESULTS On average, the cold detection thresholds were -0.47°C below skin temperature with the method of levels and -1.67°C the method of limits. Interindividual variability was significantly lower with the method of levels than with the method of limits. CONCLUSIONS These results suggest that the method of levels is more accurate than the method of limits for measuring cold detection threshold. The improvement of cold detection threshold measurement may provide new perspectives to more precisely assess the function of A-delta fibers and the spino-thalamic pathway.
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Affiliation(s)
- Segolene Lithfous
- Laboratoire de Neurosciences Cognitives et Adaptatives, UMR 7364 CNRS-UNISTRA, Strasbourg, France
| | - Olivier Després
- Laboratoire de Neurosciences Cognitives et Adaptatives, UMR 7364 CNRS-UNISTRA, Strasbourg, France
| | - Thierry Pebayle
- Centre d'Investigations Neurocognitives et Neurophysiologiques, UMS 3489 CNRS-UNISTRA, Strasbourg Cedex, France
| | - Claudia Casadio
- Centre d'Investigations Neurocognitives et Neurophysiologiques, UMS 3489 CNRS-UNISTRA, Strasbourg Cedex, France
| | - Andre Dufour
- Laboratoire de Neurosciences Cognitives et Adaptatives, UMR 7364 CNRS-UNISTRA, Strasbourg, France.,Centre d'Investigations Neurocognitives et Neurophysiologiques, UMS 3489 CNRS-UNISTRA, Strasbourg Cedex, France
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Raabe W, Walk D. Slowly conducting potentials in human sensory nerves. J Neurosci Methods 2020; 351:109045. [PMID: 33358850 DOI: 10.1016/j.jneumeth.2020.109045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 12/13/2020] [Accepted: 12/15/2020] [Indexed: 01/18/2023]
Abstract
BACKGROUND In clinical practice, small myelinated sensory fibers, Aδ-fibers, conveying mainly pain and temperature sensations, cannot be examined with available nerve conduction study techniques. Currently, these fibers can only be examined with experimental or very specialized and not commonly available nerve conduction techniques, or only indirectly with cerebral evoked potentials. NEW METHOD This study uses equipment and methods available in clinical neurophysiology laboratories to record from human sensory nerves ≥1000 averaged responses to focal, non-painful stimuli applied by a special electrode to epidermal nerves. The averaged responses to odd numbered stimuli are compared to the averaged responses to even numbered stimuli. An algorithm identifies potentials common in both averages. The 99th and 99.9th percentiles for this algorithm are obtained from control records without stimulation and applied to records with stimulation to identify potentials resulting from stimulation of intraepidermal nerves. RESULTS The algorithm identifies numerous negative and positive potentials as being different from controls at the 99th and 99.9th percentile levels. The conduction velocities of the potentials range from of 1.3-29.9 m/s and are compatible with conduction velocities of Aδ-fibers. COMPARISON WITH EXISTING METHOD(S) No existing methods. CONCLUSIONS The stimulation, recording and data analysis methods used in this study can be applied in the clinical EMG laboratory to identify Aδ-fibers in human sensory nerves.
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Affiliation(s)
- W Raabe
- Department of Neurology, University of Minnesota, Minneapolis, MN, United States.
| | - D Walk
- Department of Neurology, University of Minnesota, Minneapolis, MN, United States
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17
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Liberati G, Mulders D, Algoet M, van den Broeke EN, Santos SF, Ribeiro Vaz JG, Raftopoulos C, Mouraux A. Insular responses to transient painful and non-painful thermal and mechanical spinothalamic stimuli recorded using intracerebral EEG. Sci Rep 2020; 10:22319. [PMID: 33339884 PMCID: PMC7749115 DOI: 10.1038/s41598-020-79371-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 12/03/2020] [Indexed: 11/09/2022] Open
Abstract
Brief thermo-nociceptive stimuli elicit low-frequency phase-locked local field potentials (LFPs) and high-frequency gamma-band oscillations (GBOs) in the human insula. Although neither of these responses constitute a direct correlate of pain perception, previous findings suggest that insular GBOs may be strongly related to the activation of the spinothalamic system and/or to the processing of thermal information. To disentangle these different features of the stimulation, we compared the insular responses to brief painful thermonociceptive stimuli, non-painful cool stimuli, mechano-nociceptive stimuli, and innocuous vibrotactile stimuli, recorded using intracerebral electroencephalograpic activity in 7 epileptic patients (9 depth electrodes, 58 insular contacts). All four types of stimuli elicited consistent low-frequency phase-locked LFPs throughout the insula, possibly reflecting supramodal activity. The latencies of thermo-nociceptive and cool low-frequency phase-locked LFPs were shorter in the posterior insula compared to the anterior insula, suggesting a similar processing of thermal input initiating in the posterior insula, regardless of whether the input produces pain and regardless of thermal modality. In contrast, only thermo-nociceptive stimuli elicited an enhancement of insular GBOs, suggesting that these activities are not simply related to the activation of the spinothalamic system or to the conveyance of thermal information.
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Affiliation(s)
- Giulia Liberati
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium.
| | - Dounia Mulders
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Maxime Algoet
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | | | | | | | | | - André Mouraux
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
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Jutzeler CR, Linde LD, Rosner J, Hubli M, Curt A, Kramer JLK. Single-trial averaging improves the physiological interpretation of contact heat evoked potentials. Neuroimage 2020; 225:117473. [PMID: 33099013 DOI: 10.1016/j.neuroimage.2020.117473] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 09/12/2020] [Accepted: 10/14/2020] [Indexed: 10/23/2022] Open
Abstract
Laser and contact heat evoked potentials (LEPs and CHEPs, respectively) provide an objective measure of pathways and processes involved in nociception. The majority of studies analyzing LEP or CHEP outcomes have done so based on conventional, across-trial averaging. With this approach, evoked potential components are potentially confounded by latency jitter and ignore relevant information contained within single trials. The current study addressed the advantage of analyzing nociceptive evoked potentials based on responses to noxious stimulations within each individual trial. Single-trial and conventional averaging were applied to data previously collected in 90 healthy subjects from 3 stimulation locations on the upper limb. The primary analysis focused on relationships between single and across-trial averaged CHEP outcomes (i.e., N2P2 amplitude and N2 and P2 latencies) and subject characteristics (i.e., age, sex, height, and rating of perceived intensity), which were examined by way of linear mixed model analysis. Single-trial averaging lead to larger N2P2 amplitudes and longer N2 and P2 latencies. Age and ratings of perceived intensity were the only subject level characteristics associated with CHEPs outcomes that significantly interacted with the method of analysis (conventional vs single-trial averaging). The strength of relationships for age and ratings of perceived intensity, measured by linear fit, were increased for single-trial compared to conventional across-trial averaged CHEP outcomes. By accounting for latency jitter, single-trial averaging improved the associations between CHEPs and physiological outcomes and should be incorporated as a standard analytical technique in future studies.
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Affiliation(s)
- Catherine R Jutzeler
- Swiss Federal Institute of Technology (ETH Zurich), Department of Biosystems Science and Engineering, Mattenstrasse 26, 4058 Basel, Switzerland; SIB Swiss Institute of Bioinformatics, Switzerland; Spinal Cord Injury Center, University Hospital Balgrist, University of Zurich, Zurich, Switzerland.
| | - Lukas D Linde
- ICORD, University of British Columbia, 818W 10th Ave, Vancouver, British Columbia, Canada; Department of Anesthesiology, Pharmacology & Therapeutics, Faculty of Medicine, University of British Columbia, 818W 10th Ave, Vancouver, British Columbia, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 818W 10th Ave, Vancouver, British Columbia, Canada
| | - Jan Rosner
- Spinal Cord Injury Center, University Hospital Balgrist, University of Zurich, Zurich, Switzerland; Department of Neurology, University Hospital Bern, Inselspital, University of Bern, Bern, Switzerland
| | - Michèle Hubli
- Spinal Cord Injury Center, University Hospital Balgrist, University of Zurich, Zurich, Switzerland
| | - Armin Curt
- Spinal Cord Injury Center, University Hospital Balgrist, University of Zurich, Zurich, Switzerland
| | - John L K Kramer
- ICORD, University of British Columbia, 818W 10th Ave, Vancouver, British Columbia, Canada; Department of Anesthesiology, Pharmacology & Therapeutics, Faculty of Medicine, University of British Columbia, 818W 10th Ave, Vancouver, British Columbia, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 818W 10th Ave, Vancouver, British Columbia, Canada.
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Leone C, Di Lionardo A, Diotallevi G, Mollica C, Di Pietro G, Di Stefano G, La Cesa S, Cruccu G, Truini A. Conduction velocity of the cold spinal pathway in healthy humans. Eur J Pain 2020; 24:1923-1931. [PMID: 32735696 DOI: 10.1002/ejp.1640] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 07/19/2020] [Accepted: 07/25/2020] [Indexed: 11/05/2022]
Abstract
OBJECTIVES We aimed to investigate the conduction velocity of the cold spinal pathway in healthy humans. METHODS Using a cold stimulator consisting of micro-Peltier elements that was able to produce steep cooling ramps up to -300°C/s, we recorded cold-evoked potentials after stimulation of the dorsal midline at C5, T2, T6 and T10 vertebral levels and calculated the conduction velocity of the cold spinal pathway. In all participants, we used laser stimulation to deliver painful heat (Aδ-fibres-mediated) and warm (C-fibres-mediated) stimuli to the same sites in order to compare the conduction velocity of the cold spinal pathway with that of the nociceptive and warm spinal pathways. RESULTS Cold stimulation evoked large-amplitude vertex potentials from all stimulation sites. The mean conduction velocity of the cold spinal pathway was 12.0 m/s, which did not differ from that of the nociceptive spinal pathway (10.5 m/s). The mean conduction velocity of the warm spinal pathway was 2.0 m/s. DISCUSSION This study provides previously unreported findings regarding cold spinal pathway conduction velocity in humans that may be useful in the assessment of spinal cord lesions as well as in intraoperative monitoring during spinal surgery. SIGNIFICANCE This neurophysiological study provides previously unreported findings on cold spinal pathway conduction velocity in healthy humans. Cold-evoked potentials may represent an alternative to laser-evoked potential recording, useful to assess spinothalamic tract in patients with spinal cord lesions and monitor patients during spinal surgery.
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Affiliation(s)
- Caterina Leone
- Department of Human Neuroscience, Sapienza University, Rome, Italy
| | | | | | - Cristina Mollica
- Department of Methods and Models for Economics, Territory and Finance, Sapienza University, Rome, Italy
| | | | | | - Silvia La Cesa
- Department of Human Neuroscience, Sapienza University, Rome, Italy
| | - Giorgio Cruccu
- Department of Human Neuroscience, Sapienza University, Rome, Italy
| | - Andrea Truini
- Department of Human Neuroscience, Sapienza University, Rome, Italy
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Devigili G, Cazzato D, Lauria G. Clinical diagnosis and management of small fiber neuropathy: an update on best practice. Expert Rev Neurother 2020; 20:967-980. [PMID: 32654574 DOI: 10.1080/14737175.2020.1794825] [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: 02/06/2023]
Abstract
INTRODUCTION Small fiber neuropathy (SFN) is a heterogeneous group of disorders affecting thin myelinated Aδ and unmyelinated C fibers. Common symptoms include neuropathic pain and autonomic disturbances, and the typical clinical presentation is that of a length-dependent polyneuropathy, although other distributions could be present. AREA COVERED This review focuses on several aspects of SFN including etiology, clinical presentation, diagnostic criteria and tests, management, and future perspectives. Diagnostic challenges are discussed, encompassing the role of accurate and standardized assessment of symptoms and signs and providing clues for the clinical practice. The authors discuss the evidence in support of skin biopsy and quantitative sensory testing as diagnostic tests and present an overview of other diagnostic techniques to assess sensory and autonomic fibers dysfunction. The authors also suggest a systematic approach to the etiology including a set of laboratory tests and genetic examinations of sodium channelopathies and other rare conditions that might drive the therapeutic approach based on underlying cause or symptoms treatment. EXPERT OPINION SFN provides a useful model for neuropathic pain whose known mechanisms and cause could pave the way toward personalized treatments.
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Affiliation(s)
- Grazia Devigili
- Movement Disorders Unit, Fondazione IRCCS Istituto Neurologico "Carlo Besta" , Milan, Italy
| | - Daniele Cazzato
- Neurophysiology Unit, Fondazione IRCCS Istituto Neurologico "Carlo Besta" , Milan, Italy
| | - Giuseppe Lauria
- Neuroalgology Unit, Fondazione IRCCS Istituto Neurologico "Carlo Besta" , Milan, Italy.,Department of Biomedical and Clinical Sciences "Luigi Sacco", University of Milan , Milan, Italy
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van Neerven SGA, Mouraux A. Capsaicin-Induced Skin Desensitization Differentially Affects A-Delta and C-Fiber-Mediated Heat Sensitivity. Front Pharmacol 2020; 11:615. [PMID: 32508630 PMCID: PMC7248294 DOI: 10.3389/fphar.2020.00615] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Accepted: 04/20/2020] [Indexed: 12/19/2022] Open
Abstract
Localized neuropathic pain can be relieved following the topical application of high-concentration capsaicin. This clinical effect is thought to be related to the temporary desensitization of capsaicin- and heat-sensitive epidermal nociceptors. The objective of the present study was to examine whether the changes in thermal sensitivity induced by high-concentration topical capsaicin can be explained entirely by desensitization of capsaicin-sensitive afferents. For this purpose, we characterized, in 20 healthy human volunteers, the time course and spatial extent of the changes in sensitivity to thermal stimuli preferentially activating heat-sensitive A-fiber nociceptors, heat-sensitive C-fiber afferents, and cool-sensitive A-fiber afferents. The volar forearm was treated with a high-concentration capsaicin patch for 1 h. Transient heat, warm and cold stimuli designed to activate Aδ- and C-fiber thermonociceptors, C-fiber warm receptors, and Aδ-fiber cold receptors were applied to the skin before and after treatment at days 1, 3, and 7. Reaction times, intensity ratings, and quality descriptors were collected. The stimuli were applied both within the capsaicin-treated skin and around the capsaicin-treated skin to map the changes in thermal sensitivity. We found that topical capsaicin selectively impairs heat sensitivity without any concomitant changes in cold sensitivity. Most interestingly, we observed a differential effect on the sensitivity to thermal inputs conveyed by Aδ- and C-fibers. Reduced sensitivity to Aδ-fiber-mediated heat was restricted to the capsaicin-treated skin, whereas reduced sensitivity to C-fiber-mediated heat extended well beyond the treated skin. Moreover, the time course of the reduced sensitivity to C-fiber-mediated input was more prolonged than the reduced sensitivity to Aδ-fiber-mediated input.
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Affiliation(s)
| | - André Mouraux
- Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
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Mulders D, de Bodt C, Lejeune N, Courtin A, Liberati G, Verleysen M, Mouraux A. Dynamics of the perception and EEG signals triggered by tonic warm and cool stimulation. PLoS One 2020; 15:e0231698. [PMID: 32324752 PMCID: PMC7179871 DOI: 10.1371/journal.pone.0231698] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 03/31/2020] [Indexed: 12/27/2022] Open
Abstract
Thermosensation is crucial for humans to probe the environment and detect threats arising from noxious heat or cold. Over the last years, EEG frequency-tagging using long-lasting periodic radiant heat stimulation has been proposed as a means to study the cortical processes underlying tonic heat perception. This approach is based on the notion that periodic modulation of a sustained stimulus can elicit synchronized periodic activity in the neuronal populations responding to the stimulus, known as a steady-state response (SSR). In this paper, we extend this approach using a contact thermode to generate both heat- and cold-evoked SSRs. Furthermore, we characterize the temporal dynamics of the elicited responses, relate these dynamics to perception, and assess the effects of displacing the stimulated skin surface to gain insight on the heat- and cold-sensitive afferents conveying these responses. Two experiments were conducted in healthy volunteers. In both experiments, noxious heat and innocuous cool stimuli were applied during 75 seconds to the forearm using a Peltier-based contact thermode, with intensities varying sinusoidally at 0.2 Hz. Displacement of the thermal stimulation on the skin surface was achieved by independently controlling the Peltier elements of the thermal probe. Continuous intensity ratings to sustained heat and cold stimulation were obtained in the first experiment with 14 subjects, and the EEG was recorded in the second experiment on 15 subjects. Both contact heat and cool stimulation elicited periodic EEG responses and percepts. Compared to heat stimulation, the responses to cool stimulation had a lower magnitude and shorter latency. All responses tended to habituate along time, and this response attenuation was most pronounced for cool compared to warm stimulation, and for stimulation delivered using a fixed surface compared to a variable surface.
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Affiliation(s)
- Dounia Mulders
- ICTEAM institute, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
- IONS institute, Université Catholique de Louvain, Brussels, Belgium
- * E-mail:
| | - Cyril de Bodt
- ICTEAM institute, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Nicolas Lejeune
- IONS institute, Université Catholique de Louvain, Brussels, Belgium
| | - Arthur Courtin
- IONS institute, Université Catholique de Louvain, Brussels, Belgium
| | - Giulia Liberati
- IONS institute, Université Catholique de Louvain, Brussels, Belgium
| | - Michel Verleysen
- ICTEAM institute, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - André Mouraux
- IONS institute, Université Catholique de Louvain, Brussels, Belgium
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Rosenberger DC, Blechschmidt V, Timmerman H, Wolff A, Treede RD. Challenges of neuropathic pain: focus on diabetic neuropathy. J Neural Transm (Vienna) 2020; 127:589-624. [PMID: 32036431 PMCID: PMC7148276 DOI: 10.1007/s00702-020-02145-7] [Citation(s) in RCA: 112] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 01/19/2020] [Indexed: 02/07/2023]
Abstract
Neuropathic pain is a frequent condition caused by a lesion or disease of the central or peripheral somatosensory nervous system. A frequent cause of peripheral neuropathic pain is diabetic neuropathy. Its complex pathophysiology is not yet fully elucidated, which contributes to underassessment and undertreatment. A mechanism-based treatment of painful diabetic neuropathy is challenging but phenotype-based stratification might be a way to develop individualized therapeutic concepts. Our goal is to review current knowledge of the pathophysiology of peripheral neuropathic pain, particularly painful diabetic neuropathy. We discuss state-of-the-art clinical assessment, validity of diagnostic and screening tools, and recommendations for the management of diabetic neuropathic pain including approaches towards personalized pain management. We also propose a research agenda for translational research including patient stratification for clinical trials and improved preclinical models in relation to current knowledge of underlying mechanisms.
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Affiliation(s)
- Daniela C Rosenberger
- Department of Neurophysiology, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Vivian Blechschmidt
- Department of Neurophysiology, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Hans Timmerman
- Department of Anesthesiology, Pain Center, University Medical Center of Groningen (UMCG), University of Groningen, Groningen, The Netherlands
| | - André Wolff
- Department of Anesthesiology, Pain Center, University Medical Center of Groningen (UMCG), University of Groningen, Groningen, The Netherlands
| | - Rolf-Detlef Treede
- Department of Neurophysiology, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany.
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Hüllemann P, Nerdal A, Sendel M, Dodurgali D, Forstenpointner J, Binder A, Baron R. Cold‐evoked potentials versus contact heat‐evoked potentials—Methodological considerations and clinical application. Eur J Pain 2019; 23:1209-1220. [DOI: 10.1002/ejp.1389] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 02/22/2019] [Accepted: 03/03/2019] [Indexed: 01/11/2023]
Affiliation(s)
- Philipp Hüllemann
- Division of Neurological Pain Research and Therapy, Department of Neurology University clinic Schleswig‐Holstein Kiel Germany
| | - Annika Nerdal
- 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
| | - Dilara Dodurgali
- Division of Neurological Pain Research and Therapy, Department of Neurology University clinic Schleswig‐Holstein Kiel Germany
| | - Julia Forstenpointner
- Division of Neurological Pain Research and Therapy, Department of Neurology University clinic Schleswig‐Holstein Kiel Germany
| | - Andreas Binder
- 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
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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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Abstract
Clinical neurophysiologic investigation of pain pathways in humans is based on specific techniques and approaches, since conventional methods of nerve conduction studies and somatosensory evoked potentials do not explore these pathways. The proposed techniques use various types of painful stimuli (thermal, laser, mechanical, or electrical) and various types of assessments (measurement of sensory thresholds, study of nerve fiber excitability, or recording of electromyographic reflexes or cortical potentials). The two main tests used in clinical practice are quantitative sensory testing and pain-related evoked potentials (PREPs). In particular, PREPs offer the possibility of an objective assessment of nociceptive pathways. Three types of PREPs can be distinguished depending on the type of stimulation used to evoke pain: laser-evoked potentials, contact heat evoked potentials, and intraepidermal electrical stimulation evoked potentials (IEEPs). These three techniques investigate both small-diameter peripheral nociceptive afferents (mainly Aδ nerve fibers) and spinothalamic tracts without theoretically being able to differentiate the level of lesion in the case of abnormal results. In routine clinical practice, PREP recording is a reliable method of investigation for objectifying the existence of a peripheral or central lesion or loss of function concerning the nociceptive pathways, but not the existence of pain. Other methods, such as nerve fiber excitability studies using microneurography, more directly reflect the activities of nociceptive axons in response to provoked pain, but without detecting or quantifying the presence of spontaneous pain. These methods are more often used in research or experimental study design. Thus, it should be kept in mind that most of the results of neurophysiologic investigation performed in clinical practice assess small fiber or spinothalamic tract lesions rather than the neuronal mechanisms directly at the origin of pain and they do not provide objective quantification of pain.
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Affiliation(s)
- Jean-Pascal Lefaucheur
- Excitabilité Nerveuse et Thérapeutique, Faculté de Médecine de Créteil, Université Paris-Est-Créteil, Hôpital Henri Mondor, Créteil, France; Service de Physiologie-Explorations Fonctionnelles, Hôpital Henri Mondor, Créteil, France.
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