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Castelo-Branco L, Pacheco-Barrios K, Cardenas-Rojas A, de Melo PS, Gianlorenco AC, Gonzalez-Mego P, Marduy A, Shaik ES, Teixeira P, Caumo W, Fregni F. Cross-sectional and longitudinal analysis of conditioned pain modulation and pain in fibromyalgia: CPM as an effect modifier of pain changes over time. PHYSIOTHERAPY RESEARCH INTERNATIONAL 2024; 29:e2072. [PMID: 39055778 PMCID: PMC11268874 DOI: 10.1002/pri.2072] [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: 06/21/2023] [Accepted: 01/11/2024] [Indexed: 07/27/2024]
Abstract
Background and purpose Fibromyalgia (FM) is associated with altered descending pain modulatory pathways, which can be assessed through Conditioned Pain Modulation (CPM). In this study, we aimed to explore the relationship between CPM and self-reported baseline characteristics in patients with fibromyalgia. We also performed a longitudinal analysis exploring CPM as a potential predictor of clinical improvement over time in individuals with FM. Methods We performed cross-sectional univariable and multivariable analyses of the relationship between CPM and other variables in 41 FM patients. We then performed longitudinal analyses, building linear mixed effects models with pain in the Visual Analogue Scale (VAS) as the dependent variable, and testing for the interaction between time and CPM. We also tested the interaction between CPM and time in models using other outcomes, such as the revised Fibromyalgia Impact Questionnaire (FIQR) and Quality of Life Scale (QOLs). Results We found no association between CPM and other demographic and clinical variables in the univariable analysis. We found a statistically significant association in the multivariable linear regression model between CPM and the QOLs at baseline, after controlling for age, sex, and duration of symptoms. In the longitudinal analyses, we found that CPM is an effect modifier for clinical improvement over time for the pain VAS, QOLs and FIQR: individuals with low-efficient CPM at baseline have a different (improved) pattern of response over time when compared to those with high-efficient CPM. Conclusions Our findings suggest that CPM is not a reliable biomarker of clinical manifestations in chronic pain patients during cross-sectional assessments. However, our results are consistent with previous findings that CPM can be used to predict the evolution of clinical pain over time. We expect that our findings will help in the selection of patients with the best profile to respond to specific interventions and assist clinicians in tailoring pain treatments.
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Affiliation(s)
- Luis Castelo-Branco
- Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Kevin Pacheco-Barrios
- Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
- Universidad San Ignacio de Loyola, Vicerrectorado de Investigación, Unidad de Investigación para la Generación y Síntesis de Evidencias en Salud. Lima, Peru
| | - Alejandra Cardenas-Rojas
- Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Paulo S. de Melo
- Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Anna C. Gianlorenco
- Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
- Laboratory of neuroscience, Department of Physical Therapy, Federal University of Sao Carlos, SP, Brazil
| | - Paola Gonzalez-Mego
- Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Anna Marduy
- Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Emad S. Shaik
- Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Paulo Teixeira
- Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Wolnei Caumo
- Laboratory of Pain & Neuromodulation, Hospital de Clinicas de Porto Alegre da Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Felipe Fregni
- Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
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Kim DJ, Nascimento TD, Lim M, Danciu T, Zubieta JK, Scott PJH, Koeppe R, Kaciroti N, DaSilva AF. Exploring HD-tDCS Effect on μ-opioid Receptor and Pain Sensitivity in Temporomandibular Disorder: A Pilot Randomized Clinical Trial Study. THE JOURNAL OF PAIN 2024; 25:1070-1081. [PMID: 37956741 DOI: 10.1016/j.jpain.2023.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 10/05/2023] [Accepted: 11/01/2023] [Indexed: 11/15/2023]
Abstract
This study explored the association between experimentally-induced pain sensitivity and µ-opioid receptor (μOR) availability in patients with temporomandibular disorder (TMD) and further investigated any changes in the pain and μOR availability following high-definition transcranial direct current stimulation (HD-tDCS) over the primary motor cortex (M1) with pilot randomized clinical trials. Seven patients with TMD completed either active (n = 3) or sham treatment (n = 4) for 10 daily sessions and underwent positron emission tomography (PET) scans with [11C]carfentanil, a selective μOR agonist, a week before and after treatment. PET imaging consisted of an early resting and late phase with the sustained masseteric pain challenge by computer-controlled injection of 5% hypertonic saline. We also included 12 patients with TMD, obtained from our previous study, for baseline PET analysis. We observed that patients with more sensitivity to pain, indicated by lower infusion rate, had less μOR availability in the right amygdala during the late phase. Moreover, active M1 HD-tDCS, compared to sham, increased μOR availability post-treatment in the thalamus during the early resting phase and the amygdala, hippocampus, and parahippocampal gyrus during the late pain challenge phase. Importantly, increased μOR availability post-treatment in limbic structures including the amygdala and hippocampus was associated with decreased pain sensitivity. The findings underscore the role of the μOR system in pain regulation and the therapeutic potential of HD-tDCS for TMD. Nonetheless, large-scale studies are necessary to establish the clinical significance of these results. TRIAL REGISTRATION: ClinicalTrial.gov (NCT03724032) PERSPECTIVE: This study links pain sensitivity and µ-opioid receptors in patients with TMD. HD-tDCS over M1 improved µOR availability, which was associated with reduced pain sensitivity. Implications for TMD pain management are promising, but larger clinical trials are essential for validation.
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Affiliation(s)
- Dajung J Kim
- Headache and Orofacial Pain Effort (H.O.P.E.) Laboratory, Department of Biologic and Materials Sciences & Prosthodontics, University of Michigan School of Dentistry, Ann Arbor, Michigan; Michigan Neuroscience Institute, University of Michigan, Ann Arbor, Michigan
| | - Thiago D Nascimento
- Headache and Orofacial Pain Effort (H.O.P.E.) Laboratory, Department of Biologic and Materials Sciences & Prosthodontics, University of Michigan School of Dentistry, Ann Arbor, Michigan; Michigan Neuroscience Institute, University of Michigan, Ann Arbor, Michigan
| | - Manyoel Lim
- Food Processing Research Group, Food Convergence Research Division, Korea Food Research Institute, Jeollabuk-do, Republic of Korea
| | - Theodora Danciu
- Department of Periodontics & Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, Michigan
| | - Jon-Kar Zubieta
- Department of Psychiatry, Mass General Brigham, Newton-Wellesley Hospital, Newton, Massachusetts
| | - Peter J H Scott
- Department of Radiology, University of Michigan, Ann Arbor, Michigan
| | - Robert Koeppe
- Department of Radiology, University of Michigan, Ann Arbor, Michigan
| | - Niko Kaciroti
- Department of Biostatistics, University of Michigan, Ann Arbor, Michigan
| | - Alexandre F DaSilva
- Headache and Orofacial Pain Effort (H.O.P.E.) Laboratory, Department of Biologic and Materials Sciences & Prosthodontics, University of Michigan School of Dentistry, Ann Arbor, Michigan; Michigan Neuroscience Institute, University of Michigan, Ann Arbor, Michigan
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Caumo W, Lopes Ramos R, Vicuña Serrano P, da Silveira Alves CF, Medeiros L, Ramalho L, Tomeddi R, Bruck S, Boher L, Sanches PRS, Silva DP, Ls Torres I, Fregni F. Efficacy of Home-Based Transcranial Direct Current Stimulation Over the Primary Motor Cortex and Dorsolateral Prefrontal Cortex in the Disability Due to Pain in Fibromyalgia: A Factorial Sham-Randomized Clinical Study. THE JOURNAL OF PAIN 2024; 25:376-392. [PMID: 37689323 DOI: 10.1016/j.jpain.2023.09.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 08/07/2023] [Accepted: 09/01/2023] [Indexed: 09/11/2023]
Abstract
This randomized, double-blind, controlled clinical trial compared the effectiveness of home-based-(HB) active transcranial direct current stimulation (a-tDCS) over the left dorsolateral prefrontal cortex (l-DLPFC) or primary motor cortex (M1) with their respective sham-(s)-tDCS to determine whether a-tDCS would be more effective than s-tDCS in reducing pain and improving disability due to pain. The study included 102 patients with fibromyalgia aged 30 to 65 years old randomly assigned to 1 of 4 tDCS groups using a ratio of 2:1:2:1. The groups included l-DLPFC (a-tDCS, n = 34) and (s-tDCS, n = 17), or tDCS on the M1 (a-tDCS, n = 34) or (s-tDCS, n = 17). Patients self-administered 20 sessions of tDCS, with 2 mA for 20 minutes each day under remote supervision after in-person training. The Mixed Model for Repeated Measurements revealed that a-tDCS on DLPFC significantly reduced pain scores by 36.53% compared to 25.79% in s-tDCS. From baseline to the fourth week of treatment, a-tDCS on M1 reduced pain scores by 45.89% compared to 22.92% over s-tDCS. A generalized linear model showed a significant improvement in the disability scale in the groups that received a-tDCS compared to s-tDCS over M1 20.54% versus 2.49% (χ2 = 11.06, df = 1, P < .001]), while on DLPFC the improvement was 14.29% and 5.77%, with a borderline significance (χ2 = 3.19, df = 1, P = .06]), respectively. A higher reduction in serum brain-derived neurotrophic factor from baseline to treatment end was positively correlated with decreased pain scores regardless of the treatment group. The application of a-tDCS over M1 increased the heat pain threshold and the function of the descending pain inhibitory system. PERSPECTIVE: These findings provide important insights: (1) HB-tDCS has effectively reduced pain scores and improved disability due to fibromyalgia. (2) The study provides evidence that HB-a-tDCS is a viable and effective therapeutic approach. (3) HB-a-tDCS over M1 improved the function of the descending pain inhibitory system and increased the heat pain threshold. Finally, our findings also emphasize that brain-derived neurotrophic factor, as an index of neuroplasticity, may serve as a valuable marker associated with changes in clinical pain measures. TRIAL REGISTRATION: Number NCT03843203.
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Affiliation(s)
- Wolnei Caumo
- Post-Graduate Program in Medical Sciences, School of Medicine, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil; Laboratory of Pain and Neuromodulation at Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Rio Grande do Sul, Brazil; Pain and Palliative Care Service at HCPA, UFRGS, Porto Alegre, Rio Grande do Sul, Brazil; Department of Surgery, School of Medicine, Porto Alegre, Rio Grande do Sul, Brazil
| | - Rael Lopes Ramos
- Post-Graduate Program in Medical Sciences, School of Medicine, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
| | - Paul Vicuña Serrano
- Post-Graduate Program in Medical Sciences, School of Medicine, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
| | - Camila Fernanda da Silveira Alves
- Post-Graduate Program in Medical Sciences, School of Medicine, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil; Laboratory of Pain and Neuromodulation at Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Rio Grande do Sul, Brazil
| | - Liciane Medeiros
- Post-Graduate Program in Medical Sciences, School of Medicine, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil; Pain Pharmacology and Neuromodulation Laboratory, Preclinical Investigations, Experimental Research Center, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Rio Grande do Sul, Brazil; Postgraduate Program in Health and Human Development, La Salle University, Canoas, Rio Grande do Sul, Brazil
| | - Leticia Ramalho
- Post-Graduate Program in Medical Sciences, School of Medicine, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil
| | - Rafalea Tomeddi
- Laboratory of Pain and Neuromodulation at Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Rio Grande do Sul, Brazil
| | - Samara Bruck
- Laboratory of Pain and Neuromodulation at Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Rio Grande do Sul, Brazil
| | - Lucas Boher
- Laboratory of Pain and Neuromodulation at Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Rio Grande do Sul, Brazil; Pain and Palliative Care Service at HCPA, UFRGS, Porto Alegre, Rio Grande do Sul, Brazil; Department of Surgery, School of Medicine, Porto Alegre, Rio Grande do Sul, Brazil
| | - Paulo R S Sanches
- Laboratory of Biomedical Engineer at HCPA, Porto Alegre, Rio Grande do Sul, Brazil
| | - Danton P Silva
- Laboratory of Biomedical Engineer at HCPA, Porto Alegre, Rio Grande do Sul, Brazil
| | - Iraci Ls Torres
- Post-Graduate Program in Medical Sciences, School of Medicine, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande do Sul, Brazil; Pain Pharmacology and Neuromodulation Laboratory, Preclinical Investigations, Experimental Research Center, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Rio Grande do Sul, Brazil
| | - Felipe Fregni
- Laboratory of Neuromodulation and Center for Clinical Research Learning, Physics and Rehabilitation Department, Spaulding Rehabilitation Hospital, Boston, Massachusetts
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Gurdiel-Álvarez F, González-Zamorano Y, Lerma-Lara S, Gómez-Soriano J, Sánchez-González JL, Fernández-Carnero J, Navarro-López V. Transcranial Direct Current Stimulation (tDCS) Effects on Quantitative Sensory Testing (QST) and Nociceptive Processing in Healthy Subjects: A Systematic Review and Meta-Analysis. Brain Sci 2023; 14:9. [PMID: 38275514 PMCID: PMC10813344 DOI: 10.3390/brainsci14010009] [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: 10/24/2023] [Revised: 12/06/2023] [Accepted: 12/07/2023] [Indexed: 01/27/2024] Open
Abstract
BACKGROUND The aim of this study is to determine the effect that different tDCS protocols have on pain processing in healthy people, assessed using quantitative sensory tests (QST) and evoked pain intensity. METHODS We systematically searched in EMBASE, CINAHL, PubMed, PEDro, PsycInfo, and Web of Science. Articles on tDCS on a healthy population and regarding QST, such as pressure pain thresholds (PPT), heat pain thresholds (HPT), cold pain threshold (CPT), or evoked pain intensity were selected. Quality was analyzed using the Cochrane Risk of Bias Tool and PEDro scale. RESULTS Twenty-six RCTs were included in the qualitative analysis and sixteen in the meta-analysis. There were no significant differences in PPTs between tDCS and sham, but differences were observed when applying tDCS over S1 in PPTs compared to sham. Significant differences in CPTs were observed between tDCS and sham over DLPFC and differences in pain intensity were observed between tDCS and sham over M1. Non-significant effects were found for the effects of tDCS on HPTs. CONCLUSION tDCS anodic over S1 stimulation increases PPTs, while a-tDCS over DLPFC affects CPTs. The HPTs with tDCS are worse. Finally, M1 a-tDCS seems to reduce evoked pain intensity in healthy subjects.
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Affiliation(s)
- Francisco Gurdiel-Álvarez
- International Doctorate School, Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine, Universidad Rey Juan Carlos, 28933 Alcorcón, Spain; (F.G.-Á.); (Y.G.-Z.)
- Cognitive Neuroscience, Pain, and Rehabilitation Research Group (NECODOR), Faculty of Health Sciences, Rey Juan Carlos University, 28032 Madrid, Spain
| | - Yeray González-Zamorano
- International Doctorate School, Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine, Universidad Rey Juan Carlos, 28933 Alcorcón, Spain; (F.G.-Á.); (Y.G.-Z.)
- Cognitive Neuroscience, Pain, and Rehabilitation Research Group (NECODOR), Faculty of Health Sciences, Rey Juan Carlos University, 28032 Madrid, Spain
- Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine, Rey Juan Carlos University, 28032 Madrid, Spain;
- Brain Injury and Movement Disorders Neurorehabilitation Group (GINDAT), Institute of Life Sciences, Francisco de Vitoria University, 28223 Pozuelo de Alarcón, Spain
| | - Sergio Lerma-Lara
- Department of Physical Therapy, Centro Superior de Estudios Universitarios La Salle, Universidad Autónoma de Madrid, 28023 Madrid, Spain;
| | - Julio Gómez-Soriano
- Toledo Physiotherapy Research Group (GIFTO), Faculty of Physiotherapy and Nursing, Universidad Castilla La Mancha, 45071 Toledo, Spain;
| | - Juan Luis Sánchez-González
- Faculty of Nursing and Physiotherapy, Department of Nursing and Physiotherapy, Instituto de Investigación Biomédica de Salamanca (IBSAL), University of Salamanca, Campus Miguel de Unamuno s/n, 37007 Salamanca, Spain;
| | - Josué Fernández-Carnero
- Cognitive Neuroscience, Pain, and Rehabilitation Research Group (NECODOR), Faculty of Health Sciences, Rey Juan Carlos University, 28032 Madrid, Spain
- Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine, Rey Juan Carlos University, 28032 Madrid, Spain;
- La Paz Hospital Institute for Health Research, IdiPAZ, 28922 Madrid, Spain
- Musculoskeletal Pain and Motor Control Research Group, Faculty of Sport Sciences, Universidad Europea de Madrid, 28670 Madrid, Spain
| | - Víctor Navarro-López
- Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine, Rey Juan Carlos University, 28032 Madrid, Spain;
- Movement Analysis, Biomechanics, Ergonomics, and Motor Control Laboratory, Faculty of Health Sciences, Rey Juan Carlos University, 28922 Madrid, Spain
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Toufexis C, Macgregor M, Lewis A, Flood A. The effects of high-definition transcranial direct current stimulation on pain modulation and stress-induced hyperalgesia. Br J Pain 2023; 17:244-254. [PMID: 37342399 PMCID: PMC10278446 DOI: 10.1177/20494637221150333] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/20/2023] Open
Abstract
Background The dorsolateral prefrontal cortex (DLPFC) has been implicated in the modulation of pain-related signals. Given this involvement, manipulation of the DLPFC through transcranial direct current stimulation (tDCS) may influence internal pain modulation and decrease pain sensitivity. Acute stress is also thought to affect pain, with increased pain sensitivity observed following the presentation of an acute stressor. Methods A total of 40 healthy adults (50% male), ranging in age from 19 to 28 years (M = 22.13, SD = 1.92), were randomly allocated to one of two stimulation conditions (active and sham). High-definition tDCS (HD-tDCS) was applied for 10 min at 2 mA, with the anode placed over the left DLPFC. Stress was induced after HD-tDCS administration using a modified version of the Trier Social Stress Test. Pain modulation and sensitivity were assessed through the conditioned pain modulation paradigm and pressure pain threshold measurements, respectively. Results Compared to sham stimulation, active stimulation produced a significant increase in pain modulation capacity. No significant change in pain sensitivity and stress-induced hyperalgesia was observed following active tDCS. Conclusion This research shows novel evidence that anodal HD-tDCS over the DLPFC significantly enhances pain modulation. However, HD-tDCS had no effect on pain sensitivity or stress-induced hyperalgesia. The observed effect on pain modulation after a single dose of HD-tDCS over the DLPFC is a novel finding that informs further research into the utility of HD-tDCS in the treatment of chronic pain by presenting the DLPFC as an alternative target site for tDCS-induced analgesia.
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Affiliation(s)
- Constantino Toufexis
- Faculty of Health, Discipline of Psychology, University of Canberra, Canberra, ACT, Australia
| | - Molly Macgregor
- Faculty of Health, Discipline of Psychology, University of Canberra, Canberra, ACT, Australia
| | - Aidan Lewis
- Faculty of Health, Discipline of Psychology, University of Canberra, Canberra, ACT, Australia
| | - Andrew Flood
- Faculty of Health, Discipline of Psychology, University of Canberra, Canberra, ACT, Australia
- University of Canberra Research Institute for Sport and Exercise, University of Canberra, Canberra, ACT, Australia
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Transcranial random noise stimulation over the left dorsolateral prefrontal cortex attenuates pain expectation and perception. Clin Neurophysiol 2023; 147:1-10. [PMID: 36608385 DOI: 10.1016/j.clinph.2022.12.009] [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: 09/28/2022] [Revised: 12/04/2022] [Accepted: 12/14/2022] [Indexed: 12/29/2022]
Abstract
OBJECTIVE The dorsolateral prefrontal cortex (DLPFC) has been increasingly used as a neuromodulatory target in pain management. Transcranial random noise stimulation (tRNS) was shown to effectively elevate cortical excitability. Hence, this study aimed to characterize how tRNS over the left DLPFC affects pain expectation and perception, as well as the efficacy of conditioned-pain modulation (CPM) that reflects the function of the endogenous pain-inhibitory pathway. METHODS Using a randomized, double-blinded, and sham-controlled design, healthy participants were randomly recruited to receive tRNS with a direct current offset or sham stimulation. Their expectations and perceptions of painful electrocutaneous stimuli, as well as CPM efficacy were assessed before, immediately after, and 30 min after tRNS. RESULTS Compared with sham stimulation, perceived-pain ratings to the painful stimuli, and expected-pain ratings before painful stimuli, attenuated immediately after tRNS, whereas this analgesic effect was ineffective 30 min after tRNS. Importantly, the immediate analgesia induced by tRNS could be accounted for by tRNS effect on attenuating expected-pain ratings before certain painful stimuli. However, CPM efficacy was not significantly affected by tRNS. CONCLUSIONS These results demonstrate analgesia immediately after applying tRNS over the left DLPFC. SIGNIFICANCE This study provides evidence for analgesia of DLPFC-tRNS on an experimental pain model.
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Multifocal tDCS Targeting the Motor Network Modulates Event-Related Cortical Responses During Prolonged Pain. THE JOURNAL OF PAIN 2023; 24:226-236. [PMID: 36162791 DOI: 10.1016/j.jpain.2022.09.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 09/08/2022] [Accepted: 09/13/2022] [Indexed: 02/07/2023]
Abstract
Multifocal transcranial direct current stimulation (tDCS) targeting several brain regions is promising for inducing cortical plasticity. It remains unknown whether multifocal tDCS aimed at the resting-state motor network (network-tDCS) can revert N2-P2 cortical responses otherwise attenuated during prolonged experimental pain. Thirty-eight healthy subjects participated in 2 sessions separated by 24 hours (Day1, Day2) of active (n = 19) or sham (n = 19) network-tDCS. Experimental pain induced by topical capsaicin was maintained for 24 hours and assessed using a numerical rating scale. Electrical detection and pain thresholds, and N2-P2 evoked potentials (electroencephalography) to noxious electrical stimulation were recorded before capsaicin-induced pain (Day1-baseline), after capsaicin application (Day1-post-cap), and after 2 sessions of network-tDCS (Day2). Capsaicin induced moderate pain at Day1-post-cap, which further increased at Day2 in both groups (P = .01). Electrical detection/pain thresholds did not change over time. N2-P2 responses were reduced on Day1-post-cap compared to Day1-baseline (P = .019). At Day2 compared with Day1-post-cap, N2-P2 responses were significantly higher in the Active network-tDCS group (P<.05), while the sham group remained inhibited. These results suggest that tDCS targeting regions associated with the motor network may modulate the late evoked brain responses to noxious peripheral stimulation otherwise initially inhibited by capsaicin-induced pain. PERSPECTIVE: This study extends the evidence of N2-P2 reduction due to capsaicin-induced pain from 30 minutes to 24 hrs. Moreover, 2 sessions of tDCS targeting the motor network in the early stage of nociceptive pain may revert the inhibition of N2-P2 associated with capsaicin-induced pain.
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8
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Kold S, Graven-Nielsen T. Modulation of central pain mechanisms using high-definition transcranial direct current stimulation: A double-blind, sham-controlled study. Eur J Pain 2023; 27:303-315. [PMID: 36451616 PMCID: PMC10107535 DOI: 10.1002/ejp.2060] [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: 04/08/2022] [Revised: 11/25/2022] [Accepted: 11/29/2022] [Indexed: 12/03/2022]
Abstract
BACKGROUND The use of high-definition transcranial direct current stimulation (HD-tDCS) has shown analgesic effects in some chronic pain patients, but limited anti-nociceptive effects in healthy asymptomatic subjects. METHODS This double-blinded sham-controlled study assessed the effects of HD-tDCS applied on three consecutive days on central pain mechanisms in healthy participants with (N = 40) and without (N = 40) prolonged experimental pain induced by intramuscular injection of nerve growth factor into the right hand on Day 1. Participants were randomly assigned to Sham-tDCS (N = 20 with pain, N = 20 without) or Active-tDCS (N = 20 with pain, N = 20 without) targeting simultaneously the primary motor cortex and dorsolateral prefrontal cortex for 20 min with 2 mA stimulation intensity. Central pain mechanisms were assessed by cuff algometry on the legs measuring pressure pain sensitivity, temporal summation of pain (TSP) and conditioned pain modulation (CPM), at baseline and after HD-tDCS on Day 2 and Day 3. Based on subject's assessment of received HD-tDCS (sham or active), they were effectively blinded. RESULTS Compared with Sham-tDCS, Active-tDCS did not significantly reduce the average NGF-induced pain intensity. Tonic pain-induced temporal summation at Day 2 and Day 3 was significantly lower in the NGF-pain group under Active-tDCS compared to the pain group with Sham-tDCS (p ≤ 0.05). No significant differences were found in the cuff pressure pain detection/tolerance thresholds or CPM effect across the 3 days of HD-tDCS in any of the four groups. CONCLUSION HD-tDCS reduced the facilitation of TSP caused by tonic pain suggesting that efficacy of HD-tDCS might depend on the presence of sensitized central pain mechanisms.
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Affiliation(s)
- Sebastian Kold
- Center for Neuroplasticity and Pain (CNAP), Aalborg University, Aalborg, Denmark
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Bannister K, Hughes S. One size does not fit all: towards optimising the therapeutic potential of endogenous pain modulatory systems. Pain 2023; 164:e5-e9. [PMID: 35594517 PMCID: PMC9756434 DOI: 10.1097/j.pain.0000000000002697] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 04/20/2022] [Accepted: 04/28/2022] [Indexed: 01/09/2023]
Affiliation(s)
- Kirsty Bannister
- Central Modulation of Pain Lab, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Sam Hughes
- Pain Modulation Lab, Brain Research, and Imaging Centre (BRIC), School of Psychology, University of Plymouth, Plymouth, United Kingdom
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10
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Wen YR, Shi J, Hu ZY, Lin YY, Lin YT, Jiang X, Wang R, Wang XQ, Wang YL. Is transcranial direct current stimulation beneficial for treating pain, depression, and anxiety symptoms in patients with chronic pain? A systematic review and meta-analysis. Front Mol Neurosci 2022; 15:1056966. [PMID: 36533133 PMCID: PMC9752114 DOI: 10.3389/fnmol.2022.1056966] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 11/14/2022] [Indexed: 08/30/2023] Open
Abstract
Background Chronic pain is often accompanied by emotional dysfunction. Transcranial direct current stimulation (tDCS) has been used for reducing pain, depressive and anxiety symptoms in chronic pain patients, but its therapeutic effect remains unknown. Objectives To ascertain the treatment effect of tDCS on pain, depression, and anxiety symptoms of patients suffering from chronic pain, and potential factors that modulate the effectiveness of tDCS. Methods Literature search was performed on PubMed, Embase, Web of Science, and Cochrane Library from inception to July 2022. Randomized controlled trials that reported the effects of tDCS on pain and depression and anxiety symptoms in patients with chronic pain were included. Results Twenty-two studies were included in this review. Overall pooled results indicated that the use of tDCS can effectively alleviate short-term pain intensity [standard mean difference (SMD): -0.43, 95% confidence interval (CI): -0.75 to -0.12, P = 0.007] and depressive symptoms (SMD: -0.31, 95% CI, -0.47 to -0.14, P < 0.001), middle-term depressive symptoms (SMD: -0.35, 95% CI: -0.58 to -0.11, P = 0.004), long-term depressive symptoms (ES: -0.38, 95% CI: -0.64 to -0.13, P = 0.003) and anxiety symptoms (SMD: -0.26, 95% CI: -0.51 to -0.02, P = 0.03) compared with the control group. Conclusion tDCS may be an effective short-term treatment for the improvement of pain intensity and concomitant depression and anxiety symptoms in chronic pain patients. Stimulation site, stimulation frequency, and type of chronic pain were significant influence factors for the therapeutic effect of tDCS. Systematic review registration https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=297693, identifier: CRD42022297693.
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Affiliation(s)
- Yu-Rong Wen
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China
- Rehabilitation Medicine Center, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Jian Shi
- College of Kinesiology, Shenyang Sport University, Shenyang, China
- Rehabilitation Medicine Center, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Zheng-Yu Hu
- College of Kinesiology, Shenyang Sport University, Shenyang, China
- Rehabilitation Medicine Center, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Yang-Yang Lin
- Rehabilitation Medicine Center, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - You-Tian Lin
- Rehabilitation Medicine Center, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
- Postgraduate Research Institute, Guangzhou Sport University, Guangzhou, China
| | - Xue Jiang
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China
| | - Rui Wang
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China
| | - Xue-Qiang Wang
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China
- Department of Rehabilitation Medicine, Shanghai Shangti Orthopaedic Hospital, Shanghai, China
| | - Yu-Ling Wang
- Rehabilitation Medicine Center, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
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11
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Erdoğan ET, Küçük Z, Eskikurt G, Kurt A, Ermutlu N, Karamürsel S. Single Session Anodal Transcranial Direct Current Stimulation on Different Cortical Areas. J PSYCHOPHYSIOL 2022. [DOI: 10.1027/0269-8803/a000311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Abstract. Transcranial direct current stimulation (tDCS) studies in healthy volunteers have shown conflicting results in terms of modulation in pain thresholds. The aim of this study was to investigate how single session anodal tDCS and modulated tDCS (mtDCS) of distinct cortical areas affected pain and perception thresholds in healthy participants. Five different stimulation conditions were applied at different cortical sites to 20 healthy volunteers to investigate the effects of tDCS and mtDCS (20 Hz) on pain and perception thresholds. TDCS over the motor cortex (M1), mtDCS over the motor cortex, tDCS over the dorsolateral prefrontal cortex (DLPFC), mtDCS of the DLPFC, and mtDCS over the occipital cortex were the stimulation conditions. All of the stimulations were anodal. The stimulations were given in a randomized order at 20-minute intervals. For comparison, electrical pain and perception thresholds were obtained from the right middle finger before and during the tDCS. After each measurement, participants were asked to give a score to their pain. In repeated measures analysis of variance (RM-ANOVA) test, the Condition × Time interaction showed no significant influence on changes in pain, perception thresholds, and pain scores ( p = .48, p = .89, and p = .50, respectively). However, regardless of the condition types, there was a significant difference in pain and perceptual thresholds during tDCS ( p = .01, p = .025, respectively). Our findings did not support difference in pain and perception modulation by a single session anodal tDCS over M1 and DLPFC compared to the occipital cortex in healthy volunteers. The increase in all thresholds during tDCS, irrespective of conditions, and peripheral sensations, including an active control group, taken together, suggest a placebo effect of active tDCS. Future studies about pain and perception in healthy subjects should consider the level of experimental pain and a strong placebo effect.
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Affiliation(s)
- Ezgi Tuna Erdoğan
- Department of Physiology, School of Medicine, Koç University, Istanbul, Turkey
| | - Zeynep Küçük
- Department of Psychology, Faculty of Science and Literature, Halic University, Istanbul, Turkey
| | - Gökçer Eskikurt
- Department of Physiology, Faculty of Medicine, Istinye University, Istanbul, Turkey
| | - Adnan Kurt
- Department of Physiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Numan Ermutlu
- Department of Physiology, Faculty of Medicine, Istanbul Health and Technology University, Istanbul, Turkey
| | - Sacit Karamürsel
- Department of Physiology, School of Medicine, Koç University, Istanbul, Turkey
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12
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Endogenous Pain Modulation in Response to a Single Session of Percutaneous Electrolysis in Healthy Population: A Double-Blinded Randomized Clinical Trial. J Clin Med 2022; 11:jcm11102889. [PMID: 35629015 PMCID: PMC9143044 DOI: 10.3390/jcm11102889] [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: 04/08/2022] [Revised: 05/17/2022] [Accepted: 05/19/2022] [Indexed: 11/20/2022] Open
Abstract
The purpose of this double-blinded randomized controlled trial was to investigate whether percutaneous electrolysis (PE) is able to activate endogenous pain modulation and whether its effects are dependent on the dosage of the galvanic current. A total of 54 asymptomatic subjects aged 18–40 years were randomized into three groups, receiving a single ultrasound-guided PE intervention that consisted of a needle insertion on the lateral epicondyle tendon: sham (without electrical current), low-intensity (0.3 mA, 90 s), and high-intensity (three pulses of 3 mA, 3 s). Widespread pressure pain thresholds (PPT), conditioned pain modulation (CPM), and temporal summation (TS) were assessed in the elbow, shoulder, and leg before and immediately after the intervention. Both high and low intensity PE protocols produced an increase in PPT in the shoulder compared to sham (p = 0.031 and p = 0.027). The sham group presented a significant decrease in the CPM (p = 0.006), and this finding was prevented in PE groups (p = 0.043 and p = 0.025). In addition, high-intensity PE decreased TS respect to sham in the elbow (p = 0.047) and both PE groups reduced TS in the leg (p = 0.036 and p = 0.020) without significant differences compared to sham (p = 0.512). Consequently, a single PE intervention modulated pain processing in local and widespread areas, implying an endogenous pain modulation. The pain processing effect was independent of the dosage administrated.
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13
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Mechanisms and manifestations in musculoskeletal pain: from experimental to clinical pain settings. Pain 2022; 163:S29-S45. [PMID: 35984370 DOI: 10.1097/j.pain.0000000000002690] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 05/09/2022] [Indexed: 01/18/2023]
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14
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Impaired conditioned pain modulation was restored after a single exercise session in individuals with and without fibromyalgia. Pain Rep 2022; 7:e996. [PMID: 35399187 PMCID: PMC8984585 DOI: 10.1097/pr9.0000000000000996] [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: 10/14/2021] [Revised: 01/11/2022] [Accepted: 02/03/2022] [Indexed: 11/26/2022] Open
Abstract
Supplemental Digital Content is Available in the Text. Submaximal isometric exercise improved impaired conditioned pain modulation acutely in individuals with and without fibromyalgia, regardless of health status. Introduction: Exercise is an effective nonpharmacological intervention for individuals with fibromyalgia syndrome (FMS); however, considerable variability is observed in their pain response after a single exercise session that could be due to differences in baseline central pain inhibition (ie, conditioned pain modulation [CPM]). Objectives: This study examined the effect of isometric exercise on CPM in people with FMS and control participants. A subaim was to identify whether pain inhibition after exercise was due to differences in baseline CPM. Methods: Twenty-one individuals with FMS (50.5 ± 14.9 years) and 22 age-matched and sex-matched controls (49.2 ± 13.3 years) participated in a familiarization session and 2 randomized experimental sessions: (1) low-intensity isometric exercise and (2) quiet rest control. Conditioned pain modulation was measured before and after each experimental session. In addition, body composition and physical activity levels were collected to determine potential group differences. Results: Both groups had comparable body composition and physical activity levels and reported similar exercise-induced hypoalgesia (increase in pressure pain thresholds) at the exercising muscle (quadriceps muscle) and systemically (deltoid muscle). Both groups had a decrease in CPM after exercise and quiet rest; however, in both FMS and control participants with impaired baseline CPM, there was an increase in CPM at the deltoid muscle after exercise. Conclusion: In persons with low CPM, irrespective of health status, isometric exercise enhanced CPM at a site distal from the exercising muscle. Our results support the use of isometric exercise when initiating an exercise program especially for individuals with impaired CPM.
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15
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Jaberzadeh S, Zoghi M. Transcranial Direct Current Stimulation Enhances Exercise Performance: A Mini Review of the Underlying Mechanisms. FRONTIERS IN NEUROERGONOMICS 2022; 3:841911. [PMID: 38235480 PMCID: PMC10790841 DOI: 10.3389/fnrgo.2022.841911] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 03/18/2022] [Indexed: 01/19/2024]
Abstract
Exercise performance (EP) is affected by a combination of factors including physical, physiological, and psychological factors. This includes factors such as peripheral, central, and mental fatigue, external peripheral factors such as pain and temperature, and psychological factors such as motivation and self-confidence. During the last century, numerous studies from different fields of research were carried out to improve EP by modifying these factors. During the last two decades, the focus of research has been mainly moved toward the brain as a dynamic ever-changing organ and the ways changes in this organ may lead to improvements in physical performance. Development of centrally-acting performance modifiers such as level of motivation or sleep deprivation and the emergence of novel non-invasive brain stimulation (NIBS) techniques such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) are the key motives behind this move. This article includes three sections. Section Introduction provides an overview of the mechanisms behind the reduction of EP. The main focus of the Effects of tDCS on EP section is to provide a brief description of the effects of tDCS on maximal and submaximal types of exercise and finally, the section Mechanisms Behind the Effects of tDCS on EP provides description of the mechanisms behind the effects of tDCS on EP.
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Affiliation(s)
- Shapour Jaberzadeh
- Non-invasive Brain Stimulation and Neuroplasticity Laboratory, Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Science, Monash University, Melbourne, VIC, Australia
| | - Maryam Zoghi
- Discipline of Physiotherapy, School of Health, Federation University Australia, Churchill, VIC, Australia
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16
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Jiang X, Wang Y, Wan R, Feng B, Zhang Z, Lin Y, Wang Y. The effect of high-definition transcranial direct current stimulation on pain processing in a healthy population: A single-blinded crossover controlled study. Neurosci Lett 2022; 767:136304. [PMID: 34695451 DOI: 10.1016/j.neulet.2021.136304] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 10/18/2021] [Accepted: 10/18/2021] [Indexed: 12/28/2022]
Abstract
Transcranial direct current stimulation (tDCS) is increasingly used in pain treatment. tDCS targeting both primary motor cortex (M1) and dorsolateral prefrontal cortex (DLPFC) may modulate the descending pain inhibitory system, however, it remains controversial regarding the optimal stimulation region for pain modulation. Therefore, this study aimed to explore the effects of high-definition anodic stimulation of M1 and DLPFC on conditioned pain modulation (CPM) and pain thresholds and establish a preferred stimulation setting. Twenty-six healthy adults were randomly assigned to M1-tDCS, DLPFC-tDCS, or sham-tDCS groups. During the three sessions, each participant received an active or sham stimulation of 2 mA for 20 min, with at least 3 days' interval between sessions. Quantitative sensory tests were performed to obtain pressure pain threshold (PPT), cold pain threshold (CPT), and CPM before and after the tDCS intervention. Only M1-tDCS significantly increased CPM in healthy individuals compared with sham control (P = 0.004). No statistically significant difference was found in PPT and CPT between tDCS vs. sham control (P > 0.05). Our findings further support the important role of M1 as a target in pain regulation. Further large-scale, multicenter studies in chronic pain populations are needed to validate the alterations of distinct target brain regions related to pain and thus for an optimal target stimulation strategy in pain management.
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Affiliation(s)
- Xue Jiang
- Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China; Department of Rehabilitation Medicine, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Yafei Wang
- Department of Rehabilitation Medicine, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Ruihan Wan
- Department of Rehabilitation Medicine, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China; Department of Sport Rehabilitation, Shenyang Sport University, Shenyang, China
| | - Beibei Feng
- Department of Rehabilitation Medicine, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China; Department of Orthopedics & Traumatology, The University of Hong Kong, HKSAR, China
| | - Ziping Zhang
- Department of Rehabilitation Medicine, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China; Department of Sport Rehabilitation, Shenyang Sport University, Shenyang, China
| | - Yangyang Lin
- Department of Rehabilitation Medicine, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Yuling Wang
- Department of Rehabilitation Medicine, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
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17
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Wan R, Wang Y, Feng B, Jiang X, Xu Y, Zhang Z, Liu Y, Wang Y. Effect of High-definition Transcranial Direct Current Stimulation on Conditioned Pain Modulation in Healthy Adults: A Crossover Randomized Controlled Trial. Neuroscience 2021; 479:60-69. [PMID: 34710538 DOI: 10.1016/j.neuroscience.2021.10.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 10/16/2021] [Accepted: 10/18/2021] [Indexed: 01/07/2023]
Abstract
The disorder of the conditioned pain modulation (CPM) system is one of the main causes of pain perception in individuals. High-definition transcranial direct current stimulation (HD-tDCS) targeting specific brain areas was indicated to have an analgesic effect possibly by activating the endogenous pain inhibition pathway evident in CPM. However, discrepancies were found in previous limited studies of varied homogeneity and quality. Therefore, the present study applied 2 mA HD-tDCS (20 min) in the left primary motor cortex (M1) among 35 healthy adults with a blinded crossover study design, to investigate its effectiveness on optimizing the analgesic effect in healthy individuals through assessing changes of the CPM. The univariate and multivariate general linear models were used to evaluate the intervention effect between-group on the Δ-value (after-intervention minus before-intervention) during CPM (primary outcome), pressure pain threshold (PPT), and cold pressure threshold (CPT) (secondary outcome), respectively. A significant between-group difference in Δ-CPM was found for active stimulation. HD-tDCS significantly improved the analgesic efficiency of Δ-CPM, compared with the sham control, after adjusting the confounding factors including age, gender, psychological status, as well as the sequence effect. The changes of CPM were positively correlated with the total physical activity volume. In conclusion, our findings provide evidence support to the effectiveness of HD-tDCS on endogenous pain modulation among healthy adults. Further studies are required to explore the analgesic effect of tDCS among patients with chronic pain, thereby facilitating optimal chronic pain management.
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Affiliation(s)
- Ruihan Wan
- Department of Rehabilitation Medicine, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China; Department of Sport Rehabilitation, Shenyang Sport University, Shenyang, China
| | - Yafei Wang
- Department of Rehabilitation Medicine, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Beibei Feng
- Department of Rehabilitation Medicine, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China; Department of Orthopedics & Traumatology, The University of Hong Kong, Hong Kong Special Administrative Region
| | - Xue Jiang
- Department of Rehabilitation Medicine, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China; Department of Sport Rehabilitation, Shanghai University of Sport, Shanghai, China
| | - Yangfan Xu
- Department of Rehabilitation Medicine, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Ziping Zhang
- Department of Rehabilitation Medicine, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Ying Liu
- Department of Kinesiology, California State University, Northridge, United States
| | - Yuling Wang
- Department of Rehabilitation Medicine, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
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18
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McPhee ME, Graven-Nielsen T. Medial Prefrontal High-Definition Transcranial Direct Current Stimulation to Improve Pain Modulation in Chronic Low Back Pain: A Pilot Randomized Double-blinded Placebo-Controlled Crossover Trial. THE JOURNAL OF PAIN 2021; 22:952-967. [PMID: 33676009 DOI: 10.1016/j.jpain.2021.02.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 02/09/2021] [Accepted: 02/19/2021] [Indexed: 06/12/2023]
Abstract
Chronic low back pain (CLBP) is highly disabling, but often without identifiable source. Focus has been on impaired anti-nociceptive mechanisms contributing to pain maintenance, though methods of targeting this impairment remain limited. This randomised-controlled cross-over pilot trial used active versus sham medial prefrontal cortex (mPFC) high-definition transcranial direct current stimulation (HD-tDCS) for 3-consecutive days to improve descending pain inhibitory function. Twelve CLBP patients were included with an average visual analogue scale (VAS) pain intensity of 3.0 ± 1.5 and pain duration of 5.3 ± 2.6 years. Pressure pain thresholds (PPTs), conditioned pain modulation (CPM), and temporal summation of pain (TSP) assessed by cuff algometry, as well as pain symptomatology (intensity, unpleasantness, quality, disability) and related psychological features (pain catastrophizing, anxiety, affect), were assessed on Day1 before 3 consecutive days of HD-tDCS sessions (each 20 minutes), at 24-hours (Day 4) and 2-weeks (Day 21) following final HD-tDCS. Blinding was successful. No significant differences in psychophysical (PPT, CPM, TSP), symptomatology or psychological outcomes were observed between active and sham HD-tDCS on Day4 and Day21. CPM-effects at Day 1 negatively correlated with change in CPM-effect at Day4 following active HD-tDCS (P = .002). Lack of efficacy was attributed to several factors, not least that patients did not display impaired CPM at baseline. TRIAL REGISTRATION: : ClinicalTrials.gov (NCT03864822). PERSPECTIVE: Medial prefrontal HD-tDCS did not alter pain, psychological nor psychophysical outcomes, though correlational analysis suggested response may depend on baseline pain inhibitory efficacy, with best potential effects in patients with severe impairments in descending pain inhibitory mechanisms. Future work should focus on appropriate patient selection and optimising stimulation targeting.
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Affiliation(s)
- Megan E McPhee
- Center for Neuroplasticity and Pain (CNAP), Aalborg University, Denmark
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19
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Varela-Rodríguez S, Sánchez-González JL, Sánchez-Sánchez JL, Delicado-Miralles M, Velasco E, Fernández-de-las-Peñas C, Calderón-Díez L. Effects of Percutaneous Electrolysis on Endogenous Pain Modulation: A Randomized Controlled Trial Study Protocol. Brain Sci 2021; 11:brainsci11060801. [PMID: 34204415 PMCID: PMC8235332 DOI: 10.3390/brainsci11060801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 06/12/2021] [Accepted: 06/15/2021] [Indexed: 01/02/2023] Open
Abstract
Percutaneous electrolysis consists of the application of a galvanic electrical current throughout an acupuncture needle. It has been previously hypothesized that needling procedures' neurophysiological effects may be related to endogenous pain modulation (EPM). This protocol study describes the design of a double-blind (participant, assessor) randomized controlled trial with the aim to investigate whether percutaneous electrolysis is able to enhance EPM and whether the effect is different between two applications depending on the dosage of the galvanic electrical current. Seventy-two asymptomatic subjects not reporting the presence of pain symptoms the previous 6 months before the study, aged 18-40 years, are randomized into one of four groups: a control group who does not receive any intervention, a needling group who receives a needling intervention without electrical current, a low-intensity percutaneous electrolysis group (0.3 mA × 90 s), and a high-intensity percutaneous electrolysis group (three bouts of 3 mA × 3 s). Needling intervention consists of ultrasound-guided insertion of the needle on the common extensor tendon of the lateral epicondyle. The primary outcome is conditioned pain modulation (CPM), and secondary outcomes include widespread pressure pain sensitivity (pressure pain thresholds (PPT) over the lateral epicondyle, the cervical spine, and the tibialis anterior muscle) and temporal summation (TS). We expected that percutaneous electrolysis would have a greater influence on CPM than an isolated needling procedure and no intervention. In addition, we also postulated that there might be differences in outcome measures depending on the intensity of the electrical current during the percutaneous electrolysis application. This study makes a new contribution to the field of neurophysiological effects of percutaneous electrolysis and needling interventions.
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Affiliation(s)
- Sergio Varela-Rodríguez
- Department of Nursery and Physiotherapy, Faculty of Nursery and Physiotherapy, University of Salamanca, 37007 Salamanca, Spain; (S.V.-R.); (J.L.S.-G.); (J.L.S.-S.); (L.C.-D.)
| | - Juan Luis Sánchez-González
- Department of Nursery and Physiotherapy, Faculty of Nursery and Physiotherapy, University of Salamanca, 37007 Salamanca, Spain; (S.V.-R.); (J.L.S.-G.); (J.L.S.-S.); (L.C.-D.)
| | - José Luis Sánchez-Sánchez
- Department of Nursery and Physiotherapy, Faculty of Nursery and Physiotherapy, University of Salamanca, 37007 Salamanca, Spain; (S.V.-R.); (J.L.S.-G.); (J.L.S.-S.); (L.C.-D.)
| | | | - Enrique Velasco
- Instituto de Neurociencias de Alicante (CSIC-UMH), 03550 Alicante, Spain; (M.D.-M.); (E.V.)
| | - César Fernández-de-las-Peñas
- Department of Physical Therapy, Occupational Therapy, Physical Medicine and Rehabilitation, Universidad Rey Juan Carlos (URJC), 28922 Madrid, Spain
- Cátedra Institucional en Docencia, Clínica e Investigación en Fisioterapia: Terapia Manual, Punción Seca y Ejercicio Terapéutico, Universidad Rey Juan Carlos, 28922 Madrid, Spain
- Correspondence: or ; Tel.: +34-91-488-88-84
| | - Laura Calderón-Díez
- Department of Nursery and Physiotherapy, Faculty of Nursery and Physiotherapy, University of Salamanca, 37007 Salamanca, Spain; (S.V.-R.); (J.L.S.-G.); (J.L.S.-S.); (L.C.-D.)
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20
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Mehesz E, Karoui H, Strutton PH, Hughes SW. Exposure to an Immersive Virtual Reality Environment can Modulate Perceptual Correlates of Endogenous Analgesia and Central Sensitization in Healthy Volunteers. THE JOURNAL OF PAIN 2021; 22:707-714. [PMID: 33465506 DOI: 10.1016/j.jpain.2020.12.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 12/14/2020] [Accepted: 12/29/2020] [Indexed: 11/26/2022]
Abstract
Virtual reality (VR) has been shown to produce analgesic effects during different experimental and clinical pain states. Despite this, the top-down mechanisms are still poorly understood. In this study, we examined the influence of both a real and sham (ie, the same images in 2D) immersive arctic VR environment on conditioned pain modulation (CPM) and in a human surrogate model of central sensitization in 38 healthy volunteers. CPM and acute heat pain thresholds were assessed before and during VR/sham exposure in the absence of any sensitization. In a follow-on study, we used the cutaneous high frequency stimulation model of central sensitization and measured changes in mechanical pain sensitivity in an area of heterotopic sensitization before and during VR/sham exposure. There was an increase in CPM efficiency during the VR condition compared to baseline (P < .01). In the sham condition, there was a decrease in CPM efficiency compared to baseline (P < .01) and the real VR condition (P < .001). Neither real nor sham VR had any effect on pain ratings reported during the conditioning period or on heat pain threshold. There was also an attenuation of mechanical pain sensitivity during the VR condition indicating a lower sensitivity compared to sham (P < .05). We conclude that exposure to an immersive VR environment has no effect over acute pain thresholds but can modulate dynamic CPM responses and mechanical hypersensitivity in healthy volunteers. PERSPECTIVE: This study has demonstrated that exposure to an immersive virtual reality environment can modulate perceptual correlates of endogenous pain modulation and secondary hyperalgesia in a human surrogate pain model. These results suggest that virtual reality could provide a novel mechanism-driven analgesic strategy in patients with altered central pain processing.
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Affiliation(s)
- Erzsebet Mehesz
- The Nick Davey Laboratory, Department of Surgery and Cancer, Imperial College London, London, UK
| | - Hajer Karoui
- The Nick Davey Laboratory, Department of Surgery and Cancer, Imperial College London, London, UK
| | - Paul H Strutton
- The Nick Davey Laboratory, Department of Surgery and Cancer, Imperial College London, London, UK
| | - Sam W Hughes
- The Pain Neuroplasticity and Modulation Laboratory, Brain Research and Imaging Centre (BRIC), School of Psychology, Faculty of Health, University of Plymouth, Plymouth, UK.
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21
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Effect of anodal high-definition transcranial direct current stimulation on the pain sensitivity in a healthy population: a double-blind, sham-controlled study. Pain 2021; 162:1659-1668. [PMID: 33449508 DOI: 10.1097/j.pain.0000000000002187] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 12/30/2020] [Indexed: 02/07/2023]
Abstract
ABSTRACT High-definition transcranial direct current stimulation (HD-tDCS) of brain areas related to pain processing may provide analgesic effects evident in the sensory detection and pain thresholds. The somatosensory sensitivity was assessed after HD-tDCS targeting the primary motor cortex (M1) and/or the dorsolateral prefrontal cortex (DLPFC). Eighty-one (40 females) subjects were randomly assigned to 1 of 4 anodal HD-tDCS protocols (20 minutes) applied on 3 consecutive days: Sham-tDCS, DLPFC-tDCS, M1-tDCS, and DLPFC&M1-tDCS (simultaneous transcranial direct current stimulation [tDCS] of DLPFC and M1). Subjects and experimenter were blinded to the tDCS protocols. The somatosensory sensitivity were assessed each day, before and after each tDCS by detection and pain thresholds to thermal and mechanical skin stimulation, vibration detection thresholds, and pressure pain thresholds. Subjects were effectively blinded to the protocol, with no significant difference in rates of whether they received real or placebo tDCS between the 4 groups. Compared with the Sham-tDCS, none of the active HD-tDCS protocols caused significant changes in detection or pain thresholds. Independent of tDCS protocols, pain and detection thresholds except vibration detection were increased immediately after the first tDCS protocol compared with baseline (P < 0.05). Overall, the active stimulation protocols were not able to induce significant modulation of the somatosensory thresholds in this healthy population compared with sham-tDCS. Unrelated to the HD-tDCS protocol, a decreased sensitivity was found after the first intervention, indicating a placebo effect or possible habituation to the quantitative sensory testing assessments. These findings add to the increasing literature of null findings in the modulatory effects of HD-tDCS on the healthy somatosensory system.
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Noninvasive motor cortex stimulation effects on quantitative sensory testing in healthy and chronic pain subjects: a systematic review and meta-analysis. Pain 2021; 161:1955-1975. [PMID: 32453135 DOI: 10.1097/j.pain.0000000000001893] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 04/01/2020] [Indexed: 02/06/2023]
Abstract
ABSTRACT One of the potential mechanisms of motor cortex stimulation by noninvasive brain stimulation (NIBS) effects on pain is through the restoration of the defective endogenous inhibitory pain pathways. However, there are still limited data on quantitative sensory testing (QST), including conditioned pain modulation (CPM), supporting this mechanism. This systematic review and meta-analysis aimed to evaluate the effects of noninvasive motor cortex stimulation on pain perception as indexed by changes in QST outcomes. Database searches were conducted until July 2019 to include randomized controlled trials that performed sham-controlled NIBS on the motor cortex in either the healthy and/or pain population and assessed the QST and CPM. Quality of studies was assessed through the Cochrane tool. We calculated the Hedge's effect sizes of QST and CPM outcomes and their 95% confidence intervals (95% CIs) and performed random-effects meta-analyses. Thirty-eight studies were included (1178 participants). We found significant increases of pain threshold in healthy subjects (ES = 0.16, 95% CI = 0.02-0.31, I2 = 22.2%) and pain populations (ES = 0.48, 95% CI = 0.15-0.80, I2 = 68.8%), and homogeneous higher CPM effect (pain ratings reduction) in healthy subjects (ES = -0.39, 95% CI = -0.64 to -0.14, I2 = 17%) and pain populations (ES = -0.35, 95% CI = -0.60 to -0.11, I2 = 0%) in the active NIBS group compared with sham. These results support the idea of top-down modulation of endogenous pain pathways by motor cortex stimulation as one of the main mechanisms of pain reduction assessed by QST, which could be a useful predictive and prognostic biomarker for chronic pain personalized treatment with NIBS.
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García-Barajas G, Serrano-Muñoz D, Gómez-Soriano Pt J, Avendaño-Coy J, Fernández-Carnero J, García AM, Segura-Fragosa A, Taylor J. Efficacy of anodal suboccipital direct current stimulation for endogenous pain modulation and tonic thermal pain control in healthy participants: a randomised controlled clinical trial. PAIN MEDICINE 2021; 22:2908-2917. [PMID: 33822227 DOI: 10.1093/pm/pnab125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE The aim of this study was to assess whether anodal DCS applied to the suboccipital (SO) target area could potentiate antinociception assessed primarily with conditioned pain modulation of tonic thermal test stimuli. DESIGN Randomised double-blinded control trial. SETTING Rehabilitation hospital. SUBJECTS Healthy participants. METHODS Forty healthy participants were randomized to receive either SO-DCS or M1-DCS. The 20-minute 1.5mA anodal or sham DCS intervention were applied to each participant in randomised order during two test sessions. The primary outcome measure included heterotopic cold-pressor conditioned pain modulation (CPM) of tonic heat pain. Secondary measures included pressure pain threshold and tonic thermal pain intensity. RESULTS Heterotopic CPM of tonic heat pain intensity was unaffected by either SO-DCS or active M1, including the secondary measures of pressure pain threshold and tonic thermal pain intensity. Although low-power non-significant interactions were identified for DCS intervention (active versus sham) and time (before and after), a significant within-group inhibition of tonic cold pain was identified following SO-DCS (p = 0.011, mean [SD]: -0.76±0.88 points) and M1-DCS (p < 0.002: -0.84±0.82 points), without a significant change following sham DCS. CONCLUSIONS Although heterotopic CPM was not facilitated with either SO-DCS or M1-DCS, a general significant inhibition of tonic cold pain intensity was demonstrated following both interventions. The general effects of active DCS compared to sham on tonic cold pain-irrespective of the M1 or SO target-need to be confirmed using standard quantitative sensory testing.
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Affiliation(s)
- Guillermo García-Barajas
- Sensorimotor Function Group, Hospital Nacional de Parapléjicos, SESCAM, Toledo, Spain.,Escuela Internacional de Doctorado, Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine, Rey Juan Carlos University, Alcorcón, Spain
| | - Diego Serrano-Muñoz
- Toledo Physiotherapy Research Group (GIFTO), Faculty of Physiotherapy and Nursing, Universidad Castilla La Mancha, Toledo, Spain
| | - Julio Gómez-Soriano Pt
- Toledo Physiotherapy Research Group (GIFTO), Faculty of Physiotherapy and Nursing, Universidad Castilla La Mancha, Toledo, Spain
| | - Juan Avendaño-Coy
- Toledo Physiotherapy Research Group (GIFTO), Faculty of Physiotherapy and Nursing, Universidad Castilla La Mancha, Toledo, Spain
| | - Josue Fernández-Carnero
- Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine, Universidad Rey Juan Carlos, Madrid, Spain.,La Paz Hospital Institute for Health Research, IdiPAZ, Madrid, Spain.,Grupo Multidisciplinar de Investigación y Tratamiento del Dolor, Grupo de Excelencia Investigadora, Universidad Rey Juan Carlos-Banco de Santander, Madrid, Spain
| | - Alvaro Megía García
- Biomechanical and Technical Aids Unit, Hospital Nacional de Parapléjicos, SESCAM, Toledo, Spain
| | | | - Julian Taylor
- Sensorimotor Function Group, Hospital Nacional de Parapléjicos, SESCAM, Toledo, Spain.,Harris Manchester College, University of Oxford, Oxford, United Kingdom
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Medial Prefrontal Transcranial Direct Current Stimulation Aimed to Improve Affective and Attentional Modulation of Pain in Chronic Low Back Pain Patients. J Clin Med 2021; 10:jcm10040889. [PMID: 33671714 PMCID: PMC7926794 DOI: 10.3390/jcm10040889] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 02/09/2021] [Accepted: 02/18/2021] [Indexed: 01/09/2023] Open
Abstract
Chronic low back pain (CLBP) is often without clear underlying pathology. Affective disturbance and dysfunctional pain mechanisms, commonly observed in populations with CLBP, have, therefore, been suggested as potential contributors to CLBP development and maintenance. However, little consensus exists on how these features interact and if they can be targeted using non-invasive brain stimulation. In this pilot trial, 12 participants completed two phases (Active or Sham) of high-definition transcranial direct current stimulation (HD-tDCS) to the medial prefrontal cortex, applied for 20 min on three consecutive days. Clinical pain ratings, questionnaires, and sensitivity to painful cuff pressure were completed at baseline, then 4 trials of conditioned pain modulation (CPM; alone, with distraction using a Flanker task, with positive affect induction, and with negative affect induction using an image slideshow) were performed prior to HD-tDCS on Day 1 and Day 4 (24 h post-HD-tDCS). At baseline, attentional and affective manipulations were effective in inducing the desired state (p < 0.001) but did not significantly change the magnitude of CPM-effect. Active HD-tDCS was unable to significantly alter the magnitude of the shift in valence and arousal due to affective manipulations, nor did it alter the magnitude of CPM under any basal, attentional, or affective manipulation trial significantly on Day 4 compared to sham. The CPM-effect was greater across all manipulations on Day 1 than Day 4 (p < 0.02) but also showed poor reliability across days. Future work is needed to expand upon these findings and better understand how and if HD-tDCS can be used to enhance attentional and affective effects on pain modulation.
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Gregoret L, Zamorano AM, Graven‐Nielsen T. Effects of multifocal transcranial direct current stimulation targeting the motor network during prolonged experimental pain. Eur J Pain 2021; 25:1241-1253. [DOI: 10.1002/ejp.1743] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Luisina Gregoret
- Center for Neuroplasticity and Pain (CNAP) Department of Health Science and Technology Faculty of Medicine Aalborg University Aalborg Denmark
| | - Anna M. Zamorano
- Center for Neuroplasticity and Pain (CNAP) Department of Health Science and Technology Faculty of Medicine Aalborg University Aalborg Denmark
| | - Thomas Graven‐Nielsen
- Center for Neuroplasticity and Pain (CNAP) Department of Health Science and Technology Faculty of Medicine Aalborg University Aalborg Denmark
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Gurdiel-Álvarez F, González-Zamorano Y, Lerma Lara S, Gómez-Soriano J, Taylor J, Romero JP, Gómez Jiménez M, Fernández-Carnero J. Effectiveness of Unihemispheric Concurrent Dual-Site Stimulation over M1 and Dorsolateral Prefrontal Cortex Stimulation on Pain Processing: A Triple Blind Cross-Over Control Trial. Brain Sci 2021; 11:188. [PMID: 33557028 PMCID: PMC7913659 DOI: 10.3390/brainsci11020188] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 01/27/2021] [Accepted: 02/01/2021] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Transcranial direct current stimulation (tDCS) of the motor cortex (M1) produces short-term inhibition of pain. Unihemispheric concurrent dual-site tDCS (UHCDS-tDCS) over the M1 and dorsolateral prefrontal cortex (DLPFC) has greater effects on cortical excitability than when applied alone, although its effect on pain is unknown. The aim of this study was to test if anodal UHCDS-tDCS over the M1 and DLPFC in healthy participants could potentiate conditioned pain modulation (CPM) and diminish pain temporal summation (TS). METHODS Thirty participants were randomized to receive a sequence of UHCDS-tDCS, M1-tDCS and sham-tDCS. A 20 min 0.1 mA/cm2 anodal or sham-tDCS intervention was applied to each participant during three test sessions, according to a triple-blind cross-over trial design. For the assessment of pain processing before and after tDCS intervention, the following tests were performed: tourniquet conditioned pain modulation (CPM), pressure pain temporal summation (TS), pressure pain thresholds (PPTs), pressure pain tolerance, mechanosensitivity and cold hyperalgesia. Motor function before and after tDCS intervention was assessed with a dynamometer to measure maximal isometric grip strength. RESULTS No statistically significant differences were found between groups for CPM, pressure pain TS, PPT, pressure pain tolerance, neural mechanosensitivity, cold hyperalgesia or grip strength (p > 0.05). CONCLUSIONS Neither UHCDS-tDCS nor M1-tDCS facilitated CPM or inhibited TS in healthy subjects following one intervention session.
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Affiliation(s)
- Francisco Gurdiel-Álvarez
- Escuela Internacional de Doctorado, Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine, Universidad Rey Juan Carlos, 28933 Alcorcón, Spain; (F.G.-Á.); (Y.G.-Z.)
| | - Yeray González-Zamorano
- Escuela Internacional de Doctorado, Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine, Universidad Rey Juan Carlos, 28933 Alcorcón, Spain; (F.G.-Á.); (Y.G.-Z.)
| | - Sergio Lerma Lara
- Department of Physical Therapy, Centro Superior de Estudios Universitarios La Salle, Universidad Autónoma de Madrid, 28023 Madrid, Spain; (S.L.L.); (M.G.J.)
- Motion in Brains Research Group, Institute of Neuroscience and Sciences of the Movement (INCIMOV), Centro Superior de Estudios Universitarios La Salle, Universidad Autónoma de Madrid, 28023 Madrid, Spain
| | - Julio Gómez-Soriano
- Toledo Physiotherapy Research Group (GIFTO), Faculty of Physiotherapy and Nursing, Universidad Castilla La Mancha, 45071 Toledo, Spain;
| | - Julian Taylor
- Sensorimotor Function Group, Hospital Nacional de Parapléjicos, SESCAM, 45071 Toledo, Spain;
- Harris Manchester College, University of Oxford, Oxford OX1 3TD, UK
| | - Juan Pablo Romero
- Facultad de Ciencias Experimentales, Universidad Francisco de Vitoria, 28223 Pozuelo de Alarcón, Spain;
- Brain Damage Unit, Beata María Ana Hospital, 28007 Madrid, Spain
| | - María Gómez Jiménez
- Department of Physical Therapy, Centro Superior de Estudios Universitarios La Salle, Universidad Autónoma de Madrid, 28023 Madrid, Spain; (S.L.L.); (M.G.J.)
| | - Josué Fernández-Carnero
- Motion in Brains Research Group, Institute of Neuroscience and Sciences of the Movement (INCIMOV), Centro Superior de Estudios Universitarios La Salle, Universidad Autónoma de Madrid, 28023 Madrid, Spain
- Department of Physical and Occupational Therapy, Rehabilitation and Physical Medicine, Universidad Rey Juan Carlos, 28922 Madrid, Spain
- La Paz Hospital Institute for Health Research, IdiPAZ, 28046 Madrid, Spain
- Grupo Multidisciplinar de Investigación y Tratamiento del Dolor, Grupo de Excelencia Investigadora, Universidad Rey Juan Carlos-Banco de Santander, 28922 Madrid, Spain
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High definition transcranial direct current stimulation (HD-tDCS): A systematic review on the treatment of neuropsychiatric disorders. Asian J Psychiatr 2021; 56:102542. [PMID: 33486461 DOI: 10.1016/j.ajp.2020.102542] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 12/14/2020] [Accepted: 12/28/2020] [Indexed: 12/15/2022]
Abstract
HD-tDCS (High-definition transcranial direct current stimulation) is a novel non-invasive brain stimulation (NIBS) technique based on the principle that when weak intensity electric currents are targeted on specific areas of the scalp, they cause underlying cortical stimulation. HD-tDCS shares its technical methodology with conventional tDCS (montage comprising of one anode and one cathode) except for a few modifications that are believed to have focal and longer-lasting neuromodulation effects. Although HD-tDCS is a recently available NIBS technique, impactful studies, case reports, and few controlled trials have been conducted in this context, facilitating an understanding of its neurobiological effects and the clinical translation of the same in health care set-up. The current article narratively reviews the mechanism of action of HD-tDCS, and it systematically examines the cognitive, clinical, and neurobiological effects of HD-tDCS in healthy volunteers as well as patients with neuropsychiatric conditions. Thus, this review attempts to explore the role of HD-tDCS in present-day practice and the future in the context of various neurological and psychiatric disorders.
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Saldanha JS, Zortea M, Torres ILDS, Fregni F, Caumo W. Age as a Mediator of tDCS Effects on Pain: An Integrative Systematic Review and Meta-Analysis. Front Hum Neurosci 2020; 14:568306. [PMID: 33192397 PMCID: PMC7654216 DOI: 10.3389/fnhum.2020.568306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 09/22/2020] [Indexed: 12/25/2022] Open
Abstract
Introduction: The transcranial direct current stimulation (tDCS) is a neuromodulatory technique with the potential to decrease pain scores and to improve chronic pain treatment. Although age is an essential factor that might impact the tDCS effect, most studies are solely conducted in adults. Therefore, the age limitation presents a critical research gap in this field and can be shown by only a handful of studies that have included other age groups. To examine the evidence upon the tDCS effect on pain scores on children, adolescents, or elderly, and indirectly, to infer the age-dependent impact on tDCS effects, we conducted a systematic review and meta-analysis. Methods: A systematic review searching the following databases: PubMed, EMBASE, and Science Direct using the following search terms adapted according to MeSh or Entree: [(“Adolescent” OR “Children” OR “Elderly”) AND (“tDCS”) AND (“Pain” OR “Pain threshold”) AND (“dorsolateral prefrontal cortex” OR “Motor cortex)] up to April 20th, 2020. We retrieved 228 articles, 13 were included in the systematic review, and five studies with elderly subjects that had their outcomes assessed by pain score or pain threshold were included in the meta-analysis. Results: For the analysis of pain score, 96 individuals received active stimulation, and we found a favorable effect for active tDCS to reduce pain score compared to sham (P = 0.002). The standardized difference was −0.76 (CI 95% = −1.24 to −0.28). For the pain threshold, the analysis showed no significant difference between active and sham tDCS. We reviewed two studies with adolescents: one study using anodal tDCS over the prefrontal cortex reported a reduction in pain scores. However, the second study reported an increase in pain sensitivity for the dorsolateral prefrontal cortex (DLPFC) stimulation. Conclusion: Our findings suggest tDCS may reduce pain levels in the elderly group. Nevertheless, the small number of studies included in this review—and the considerable heterogeneity for clinical conditions and protocols of stimulation present—limits the support of tDCS use for pain treatment in elderly people. Larger studies on the tDCS effect on pain are needed to be conducted in elderly and adolescents, also evaluating different montages and electrical current intensity.
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Affiliation(s)
- Júlia Schirmer Saldanha
- Graduate Program in Medical Sciences, School of Medicine, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.,Laboratory of Pain and Neuromodulation, Clinical Research Center, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Brazil
| | - Maxciel Zortea
- Graduate Program in Medical Sciences, School of Medicine, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.,Laboratory of Pain and Neuromodulation, Clinical Research Center, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Brazil
| | - Iraci Lucena da Silva Torres
- Pharmacology of Pain and Neuromodulation: Pre-Clinical Investigations Research Group, Universidade Federal do Rio Grande Do Sul (UFRGS), Porto Alegre, Brazil
| | - Felipe Fregni
- Laboratory of Neuromodulation and Center for Clinical Research Learning, Physics and Rehabilitation Department, Spaulding Rehabilitation Hospital, Boston, MA, United States
| | - Wolnei Caumo
- Graduate Program in Medical Sciences, School of Medicine, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.,Laboratory of Pain and Neuromodulation, Clinical Research Center, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Brazil.,Pain and Palliative Care Service, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Brazil
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Borovskis J, Cavaleri R, Blackstock F, Summers SJ. Transcranial Direct Current Stimulation Accelerates The Onset of Exercise-Induced Hypoalgesia: A Randomized Controlled Study. THE JOURNAL OF PAIN 2020; 22:263-274. [PMID: 32927091 DOI: 10.1016/j.jpain.2020.08.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 08/09/2020] [Accepted: 08/24/2020] [Indexed: 02/06/2023]
Abstract
Exercise-induced hypoalgesia (EIH) describes acute reductions in pain that occur following exercise. Current evidence suggests that the magnitude of EIH is small-to-moderate at best, warranting exploration of novel avenues to bolster these effects. Transcranial direct current stimulation (tDCS) has been shown to relieve pain and represents a promising intervention that may enhance EIH. This study aimed to determine whether anodal tDCS of the primary motor cortex (M1) can augment EIH in healthy individuals experiencing experimentally-induced musculoskeletal pain. Twenty-four healthy subjects attended 2 experimental sessions ("Day 0" and "Day 2"). On Day 0, subjects were injected with nerve growth factor into their right extensor carpi radialis brevis to induce persistent elbow pain. On Day 2, each subject received active or sham tDCS over M1 followed by an isometric grip exercise. Pain intensity, muscle soreness, sensitivity (pressure pain thresholds), and conditioned pain modulation were assessed prior to the nerve growth factor injection, on Day 2 before tDCS, immediately post-exercise, and 15 minutes post-exercise. Active tDCS expedited the onset of EIH, inducing immediate reductions in pain intensity that were not present until 15 minutes post-exercise in the sham group. However, active tDCS did not reduce muscle soreness or sensitivity when compared to sham tDCS. PERSPECTIVE: These findings suggest that active tDCS accelerates the onset of EIH in healthy individuals experiencing experimentally-induced pain. This may represent a promising means of enhancing adherence to exercise protocols. However, larger randomised controlled trials in persistent pain populations are required to confirm the clinical impact of these findings.
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Affiliation(s)
- Jana Borovskis
- School of Health Sciences, Western Sydney University, NSW 2560, Australia; Brain Stimulation and Rehabilitation (BrainStAR) Lab, Western Sydney University, NSW 2560, Australia
| | - Rocco Cavaleri
- School of Health Sciences, Western Sydney University, NSW 2560, Australia; Brain Stimulation and Rehabilitation (BrainStAR) Lab, Western Sydney University, NSW 2560, Australia
| | | | - Simon J Summers
- School of Health Sciences, Western Sydney University, NSW 2560, Australia; Brain Stimulation and Rehabilitation (BrainStAR) Lab, Western Sydney University, NSW 2560, Australia; Discipline of Sport and Exercise Science, Faculty of Health, University of Canberra, ACT 2617, Australia; Research School of Biology, Australian National University, ACT 2600, Australia.
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Pacheco-Barrios K, Cardenas-Rojas A, Thibaut A, Costa B, Ferreira I, Caumo W, Fregni F. Methods and strategies of tDCS for the treatment of pain: current status and future directions. Expert Rev Med Devices 2020; 17:879-898. [PMID: 32845195 PMCID: PMC7674241 DOI: 10.1080/17434440.2020.1816168] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Accepted: 08/25/2020] [Indexed: 12/21/2022]
Abstract
INTRODUCTION Transcranial direct current stimulation (tDCS) is a noninvasive neuromodulation technique that has been widely studied for the treatment of chronic pain. It is considered a promising and safe alternative pain therapy. Different targets have been tested, each having their own particular mechanisms for modulating pain perception. AREAS COVERED We discuss the current state of the art of tDCS to manage pain and future strategies to optimize tDCS' effects. Current strategies include primary motor cortex tDCS, prefrontal tDCS and tDCS combined with behavioral interventions while future strategies, on the other hand, include high-intensity tDCS, transcutaneous spinal direct current stimulation, cerebellar tDCS, home-based tDCS, and tDCS with extended number of sessions. EXPERT COMMENTARY It has been shown that the stimulation of the prefrontal and primary motor cortex is efficient for pain reduction while a few other new strategies, such as high-intensity tDCS and network-based tDCS, are believed to induce strong neuroplastic effects, although the underlying neural mechanisms still need to be fully uncovered. Hence, conventional tDCS approaches demonstrated promising effects to manage pain and new strategies are under development to enhance tDCS effects and make this approach more easily available by using, for instance, home-based devices.
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Affiliation(s)
- Kevin Pacheco-Barrios
- Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Boston, Massachusetts, USA
- Universidad San Ignacio de Loyola, Vicerrectorado de Investigación, Unidad de Investigación para la Generación y Síntesis de Evidencias en Salud. Lima, Peru
| | - Alejandra Cardenas-Rojas
- Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Aurore Thibaut
- Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Boston, Massachusetts, USA
- Coma Science Group, GIGA Consciousness, University of Liege, Liège, Belgium
| | - Beatriz Costa
- Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Isadora Ferreira
- Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Wolnei Caumo
- Pain and Palliative Care Service at Hospital de Clínicas de Porto Alegre (HCPA), Laboratory of Pain and Neuromodulation at UFRGS, Porto Alegre, Brazil
| | - Felipe Fregni
- Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Boston, Massachusetts, USA
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Pellegrini M, Zoghi M, Jaberzadeh S. The effects of transcranial direct current stimulation on corticospinal and cortico-cortical excitability and response variability: Conventional versus high-definition montages. Neurosci Res 2020; 166:12-25. [PMID: 32610058 DOI: 10.1016/j.neures.2020.06.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 06/08/2020] [Accepted: 06/11/2020] [Indexed: 01/19/2023]
Abstract
Response variability following transcranial direct current stimulation (tDCS) highlights need for exploring different tDCS electrode montages. Corticospinal excitability (CSE), cortico-cortical excitability and intra-individual variability was compared following conventional and high-definition (HD) anodal (a-tDCS) and cathodal (c-tDCS) tDCS. Fifteen healthy males attended four sessions at-least one-week apart: conventional a-tDCS, conventional c-tDCS, HD-a-tDCS, HD-c-tDCS. TDCS was administered (1 mA, 10-minutes) over primary motor cortex (M1), via 6 × 4 cm active and 7 × 5 cm return electrodes (conventional tDCS) and 4 × 1 ring-electrodes 3.5 cm apart over M1 (HD-tDCS). For CSE, twenty-five single-pulse transcranial magnetic stimulation (TMS) peak-to-peak motor evoked potentials (MEP) were recorded at baseline, 0-minutes and 30-minutes post-tDCS. Twenty-five paired-pulse MEPs with 3-millisecond (ms) inter-pulse interval (IPI) and twenty-five at 10 ms assessed short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF). MEP standardised z-values standard deviations represented intra-individual variability. No significant changes in CSE from baseline were reported for all four interventions. No significant differences were reported in CSE between conventional and HD a-tDCS, but significant differences between conventional and HD c-tDCS 0-minutes post-tDCS. Conventional tDCS significantly reduced intra-individual variability compared to HD-tDCS for a-tDCS (0-minutes) and c-tDCS (30-minutes). No changes were reported for SICI/ICF. These novel findings of increased intra-individual variability following HD-tDCS, at the current stimulus parameters, highlight need for further nuanced research and refinement to optimise the HD-tDCS dosage-response relationship.
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Affiliation(s)
- Michael Pellegrini
- Non-Invasive Brain Stimulation and Neuroplasticity Laboratory, Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Science, Monash University, Melbourne, Australia.
| | - Maryam Zoghi
- Department of Rehabilitation, Nutrition and Sport, School of Allied Health, Discipline of Physiotherapy, La Trobe University, Melbourne, Australia
| | - Shapour Jaberzadeh
- Non-Invasive Brain Stimulation and Neuroplasticity Laboratory, Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Science, Monash University, Melbourne, Australia
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Sessions of Prolonged Continuous Theta Burst Stimulation or High-frequency 10 Hz Stimulation to Left Dorsolateral Prefrontal Cortex for 3 Days Decreased Pain Sensitivity by Modulation of the Efficacy of Conditioned Pain Modulation. THE JOURNAL OF PAIN 2019; 20:1459-1469. [DOI: 10.1016/j.jpain.2019.05.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 04/29/2019] [Accepted: 05/22/2019] [Indexed: 12/16/2022]
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Castelo-Branco L, Uygur Kucukseymen E, Duarte D, El-Hagrassy MM, Bonin Pinto C, Gunduz ME, Cardenas-Rojas A, Pacheco-Barrios K, Yang Y, Gonzalez-Mego P, Estudillo-Guerra A, Candido-Santos L, Mesia-Toledo I, Rafferty H, Caumo W, Fregni F. Optimised transcranial direct current stimulation (tDCS) for fibromyalgia-targeting the endogenous pain control system: a randomised, double-blind, factorial clinical trial protocol. BMJ Open 2019; 9:e032710. [PMID: 31672712 PMCID: PMC6830717 DOI: 10.1136/bmjopen-2019-032710] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
INTRODUCTION Fibromyalgia (FM) is a common debilitating condition with limited therapeutic options. Medications have low efficacy and are often associated with adverse effects. Given that FM is associated with a defective endogenous pain control system and central sensitisation, combining interventions such as transcranial direct current stimulation (tDCS) and aerobic exercise (AE) to modulate pain-processing circuits may enhance pain control. METHODS AND ANALYSIS A prospective, randomised (1:1:1:1), placebo-controlled, double-blind, factorial clinical trial will test the hypothesis that optimised tDCS (16 anodal tDCS sessions combined with AE) can restore of the pain endogenous control system. Participants with FM (n=148) will undergo a conditioning exercise period and be randomly allocated to one of four groups: (1) active tDCS and AE, (2) sham tDCS and AE, (3) active tDCS and non-aerobic exercise (nAE) or (4) sham tDCS and nAE. Pain inhibitory activity will be assessed using conditioned pain modulation (CPM) and temporal slow pain summation (TSPS)-primary outcomes. Secondary outcomes will include the following assessments: Transcranial magnetic stimulation and electroencephalography as cortical markers of pain inhibitory control and thalamocortical circuits; secondary clinical outcomes on pain, FM, quality of life, sleep and depression. Finally, the relationship between the two main mechanistic targets in this study-CPM and TSPS-and changes in secondary clinical outcomes will be tested. The change in the primary efficacy endpoint, CPM and TSPS, from baseline to week 4 of stimulation will be tested with a mixed linear model and adjusted for important demographic variables. ETHICS AND DISSEMINATION This study obeys the Declaration of Helsinki and was approved by the Institutional Review Board (IRB) of Partners Healthcare under the protocol number 2017P002524. Informed consent will be obtained from participants. Study findings will be reported in conferences and peer-reviewed journal publications. TRIAL REGISTRATION NUMBER NCT03371225.
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Affiliation(s)
- Luis Castelo-Branco
- Neuromodulation Center/Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Elif Uygur Kucukseymen
- Neuromodulation Center/Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Dante Duarte
- Neuromodulation Center/Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Mirret M El-Hagrassy
- Neuromodulation Center/Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Camila Bonin Pinto
- Neuromodulation Center/Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Muhammed Enes Gunduz
- Neuromodulation Center/Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Alejandra Cardenas-Rojas
- Neuromodulation Center/Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Kevin Pacheco-Barrios
- Neuromodulation Center/Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Yiling Yang
- Neuromodulation Center/Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Paola Gonzalez-Mego
- Neuromodulation Center/Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Anayali Estudillo-Guerra
- Neuromodulation Center/Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Ludmilla Candido-Santos
- Neuromodulation Center/Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Ines Mesia-Toledo
- Neuromodulation Center/Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Haley Rafferty
- Neuromodulation Center/Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Wolnei Caumo
- Laboratory of Pain & Neuromodulation, Hospital de Clinicas de Porto Alegre da Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Felipe Fregni
- Neuromodulation Center/Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, Massachusetts, USA
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Alsouhibani A, Vaegter HB, Hoeger Bement M. Systemic Exercise-Induced Hypoalgesia Following Isometric Exercise Reduces Conditioned Pain Modulation. PAIN MEDICINE 2019; 20:180-190. [PMID: 29618132 DOI: 10.1093/pm/pny057] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Objective Physically active individuals show greater conditioned pain modulation (CPM) compared with less active individuals. Understanding the effects of acute exercise on CPM may allow for a more targeted use of exercise in the management of pain. This study investigated the effects of acute isometric exercise on CPM. In addition, the between-session and within-session reliability of CPM was investigated. Design Experimental, randomized crossover study. Setting Laboratory at Marquette University. Subjects Thirty healthy adults (19.3±1.5 years, 15 males). Methods Subjects underwent CPM testing before and after isometric exercise (knee extension, 30% maximum voluntary contraction for three minutes) and quiet rest in two separate experimental sessions. Pressure pain thresholds (PPTs) at the quadriceps and upper trapezius muscles were assessed before, during, and after ice water immersions. Results PPTs increased during ice water immersion (i.e., CPM), and quadriceps PPT increased after exercise (P < 0.05). CPM decreased similarly following exercise and quiet rest (P > 0.05). CPM within-session reliability was fair to good (intraclass correlation coefficient [ICC] = 0.43-0.70), and the between-session reliability was poor (ICC = 0.20-0.35). Due to the variability in the systemic exercise-induced hypoalgesia (EIH) response, participants were divided into systemic EIH responders (N = 9) and nonresponders (N = 21). EIH responders experienced attenuated CPM following exercise (P = 0.03), whereas the nonresponders showed no significant change (P > 0.05). Conclusions Isometric exercise decreased CPM in individuals who reported systemic EIH, suggesting activation of shared mechanisms between CPM and systemic EIH responses. These results may improve the understanding of increased pain after exercise in patients with chronic pain and potentially attenuated CPM.
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Affiliation(s)
- Ali Alsouhibani
- Clinical and Translational Rehabilitation Health Sciences Program, Department of Physical Therapy, College of Health Sciences, Marquette University, Milwaukee, Wisconsin, USA
| | - Henrik Bjarke Vaegter
- Pain Research Group, Pain Center South, Department of Anesthesiology and Intensive Care Medicine, Odense University Hospital, Odense, Denmark.,Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
| | - Marie Hoeger Bement
- Clinical and Translational Rehabilitation Health Sciences Program, Department of Physical Therapy, College of Health Sciences, Marquette University, Milwaukee, Wisconsin, USA
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Thibaut A, Ohrtman EA, Morales-Quezada L, Simko LC, Ryan CM, Zafonte R, Schneider JC, Fregni F. Distinct behavioral response of primary motor cortex stimulation in itch and pain after burn injury. Neurosci Lett 2019; 690:89-94. [PMID: 30312754 PMCID: PMC8279808 DOI: 10.1016/j.neulet.2018.10.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 09/27/2018] [Accepted: 10/08/2018] [Indexed: 12/18/2022]
Abstract
It is still unclear whether chronic neuropathic pain and itch share similar neural mechanisms. They are two of the most commonly reported challenges following a burn injury and can be some of the most difficult to treat. Transcranial direct current stimulation (tDCS) has previously been studied as a method to modulate pain related neural circuits. Therefore, we aimed to test the effects of tDCS on post-burn neuropathic pain and itch as to understand whether this would induce a simultaneous modulation of these two sensory manifestations. We conducted a pilot randomized controlled clinical trial comprised of two phases of active or sham M1 tDCS (Phase I: 10 sessions followed by a follow-up period of 8 weeks; Phase II: additional 5 sessions followed by a follow-up period of 8 weeks, and a final visit 12 months from baseline). Pain levels were assessed with the Brief Pain Inventory (BPI) and levels of itch severity were assessed with the Visual Analogue Scale (VAS). Measurements were collected at baseline, after the stimulation periods, at 2, 4 and 8-week follow up both for Phase I and II, and at the final visit. Sixteen patients were assigned to the active group and 15 to the sham group. Ten sessions of active tDCS did not reduce the level of pain or itch. We identified that itch levels were reduced at 2-week follow-up after the sham tDCS session, while no placebo effect was found for the active group. No difference between active and sham groups was observed for pain. We did not find any treatment effects during Phase II. Based on these findings, it seems that an important placebo effect occurred during sham tDCS for itch, while active M1 tDCS seems to disrupt sensory compensatory mechanisms. We hypothesize that pain and itch are complementary but distinct mechanisms of adaptation after peripheral sensory injury following a burn injury and need to be treated differently.
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Affiliation(s)
- Aurore Thibaut
- Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, MA, United States; GIGA-Institute and Neurology Department, University of Liège and University hospital of Liège, Liège, Belgium.
| | - Emily A Ohrtman
- Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, MA, United States
| | - Leon Morales-Quezada
- Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, MA, United States
| | - Laura C Simko
- Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, MA, United States
| | - Colleen M Ryan
- Massachusetts General Hospital, Harvard Medical School, Boston, MA, Shriners Hospitals for Children-Boston, Boston, MA, United States
| | - Ross Zafonte
- Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, MA, United States; Massachusetts General Hospital and Brigham and Womens Hospital, Boston, United States
| | - Jeffrey C Schneider
- Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, MA, United States
| | - Felipe Fregni
- Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, MA, United States.
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Hughes S, Grimsey S, Strutton PH. Primary Motor Cortex Transcranial Direct Current Stimulation Modulates Temporal Summation of the Nociceptive Withdrawal Reflex in Healthy Subjects. PAIN MEDICINE 2018; 20:1156-1165. [DOI: 10.1093/pm/pny200] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Sam Hughes
- The Nick Davey Laboratory, Faculty of Medicine, Imperial College London, London, UK
| | - Sybil Grimsey
- The Nick Davey Laboratory, Faculty of Medicine, Imperial College London, London, UK
| | - Paul H Strutton
- The Nick Davey Laboratory, Faculty of Medicine, Imperial College London, London, UK
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Duarte D, Castelo-Branco LEC, Uygur Kucukseymen E, Fregni F. Developing an optimized strategy with transcranial direct current stimulation to enhance the endogenous pain control system in fibromyalgia. Expert Rev Med Devices 2018; 15:863-873. [PMID: 30501532 PMCID: PMC6644718 DOI: 10.1080/17434440.2018.1551129] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 11/19/2018] [Indexed: 12/22/2022]
Abstract
INTRODUCTION Fibromyalgia affects more than 5 million people in the United States and has a detrimental impact on individuals' quality of life. Current pharmacological treatments provide limited benefits to relieve the pain of fibromyalgia, along with a risk of adverse effects; a scenario that explains the increasing interest for multimodal approaches. A tailored strategy to focus on this dysfunctional endogenous pain inhibitory system is transcranial direct current stimulation (tDCS) of the primary motor cortex. By combining tDCS with aerobic exercise, the effects can be optimized. Areas covered: The relevant literature was reviewed and discussed the methodological issues for designing a mechanistic clinical trial to test this combined intervention. Also, we reviewed the neural control of different pathways that integrate the endogenous pain inhibitory system, as well as the effects of tDCS and aerobic exercise both alone and combined. In addition, potential neurophysiological assessments are addressed: conditioned pain modulation, temporal slow pain summation, transcranial magnetic stimulation, and electroencephalography in the context of fibromyalgia. Expert commentary: By understanding the neural mechanisms underlying pain processing and potential optimized interventions in fibromyalgia with higher accuracy, the field has an evident potential of advancement in the direction of new neuromarkers and tailored therapies.
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Affiliation(s)
- Dante Duarte
- a Laboratory of Neuromodulation & Center for Clinical Research Learning, Department of Physical Medicine and Rehabilitation , Spaulding Rehabilitation Hospital, Harvard Medical School , Boston , MA , USA
| | - Luis Eduardo Coutinho Castelo-Branco
- a Laboratory of Neuromodulation & Center for Clinical Research Learning, Department of Physical Medicine and Rehabilitation , Spaulding Rehabilitation Hospital, Harvard Medical School , Boston , MA , USA
| | - Elif Uygur Kucukseymen
- a Laboratory of Neuromodulation & Center for Clinical Research Learning, Department of Physical Medicine and Rehabilitation , Spaulding Rehabilitation Hospital, Harvard Medical School , Boston , MA , USA
| | - Felipe Fregni
- a Laboratory of Neuromodulation & Center for Clinical Research Learning, Department of Physical Medicine and Rehabilitation , Spaulding Rehabilitation Hospital, Harvard Medical School , Boston , MA , USA
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Tavares DRB, Okazaki JEF, Rocha AP, Santana MVDA, Pinto ACPN, Civile VT, Santos FC, Fregni F, Trevisani VFM. Effects of Transcranial Direct Current Stimulation on Knee Osteoarthritis Pain in Elderly Subjects With Defective Endogenous Pain-Inhibitory Systems: Protocol for a Randomized Controlled Trial. JMIR Res Protoc 2018; 7:e11660. [PMID: 30373731 PMCID: PMC6234349 DOI: 10.2196/11660] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 10/02/2018] [Accepted: 10/03/2018] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Knee osteoarthritis (OA) has been the main cause behind chronic pain and disabilities in the elderly population. The traditional treatment for knee OA pain currently concerns a number of combinations of pharmacological and nonpharmacological therapies. However, such combinations have displayed little effects on a significant group of subjects. In addition to this, pharmacological treatments often cause adverse effects, which limits their use on this population. Previous studies showed that chronic knee OA pain may be associated with maladaptive compensatory plasticity in pain-related neural central circuits indexed by a defective descending pain-inhibitory system. Transcranial direct current stimulation (tDCS) can revert some of these maladaptive changes, thus decreasing chronic pain sensation. Numerous studies have demonstrated that the use of anodal tDCS stimulation over the primary motor cortex (M1) has positive effects on chronic neuropathic pain. Yet, data on OA pain in elderly patients, including its effects on the endogenous pain-inhibitory system, remain limited. OBJECTIVE The objective of this study is to evaluate the efficacy of tDCS in reducing pain intensity caused by knee OA in elderly subjects with defective endogenous pain-inhibitory systems. METHODS We designed a randomized, sham-controlled, single-center, double-blinded clinical trial. Patients with knee OA who have maintained a chronic pain level during the previous 6 months and report a pain score of 4 or more on a 0-10 numeric rating scale (NRS) for pain in that period will undergo a conditioned pain modulation (CPM) task. Participants who present a reduced CPM response, defined as a decrease in NRS during the CPM task of less than 10%, and meet all of the inclusion criteria will be randomly assigned to receive 15 sessions of 2 mA active or sham tDCS for 20 minutes. A sample size of 94 subjects was calculated. The Brief Pain Inventory pain items will be used to assess pain intensity as our primary outcome. Secondary outcomes will include pain impact on functioning, mobility performance, quality of life, CPM, pressure pain threshold, touch-test sensory evaluation, and safety. Follow-up visits will be performed 2, 4, and 8 weeks following intervention. The data will be analyzed using the principle of intention-to-treat. RESULTS This study was approved by the institutional review board with the protocol number 1685/2016. The enrollment started in April 2018; at the time of publication of this protocol, 25 subjects have been enrolled. We estimate we will complete the enrollment process within 2 years. CONCLUSIONS This clinical trial will provide relevant data to evaluate if anodal tDCS stimulation over M1 can decrease chronic knee OA pain in elderly subjects with defective CPM. In addition, this trial will advance the investigation of the role of central sensitization in knee OA and evaluate how tDCS stimulation may affect it. TRIAL REGISTRATION ClinicalTrials.gov NCT03117231; https://clinicaltrials.gov/ct2/show/NCT03117231 (Archived by WebCite at http://webcitation.org/73WM1LCdJ). INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID) RR1-10.2196/11660.
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Affiliation(s)
- Daniela Regina Brandao Tavares
- Department of Evidence-Based Medicine, Brazilian Cochrane Centre, Federal University of São Paulo, Sao Paulo, Brazil.,Department of Geriatrics and Gerontology, Federal University of São Paulo, Sao Paulo, Brazil
| | - Jane Erika Frazao Okazaki
- Department of Evidence-Based Medicine, Brazilian Cochrane Centre, Federal University of São Paulo, Sao Paulo, Brazil.,Department of Geriatrics and Gerontology, Federal University of São Paulo, Sao Paulo, Brazil
| | - Aline Pereira Rocha
- Department of Evidence-Based Medicine, Brazilian Cochrane Centre, Federal University of São Paulo, Sao Paulo, Brazil
| | - Marcia Valeria De Andrade Santana
- Department of Evidence-Based Medicine, Brazilian Cochrane Centre, Federal University of São Paulo, Sao Paulo, Brazil.,Department of Geriatrics and Gerontology, Federal University of São Paulo, Sao Paulo, Brazil
| | - Ana Carolina Pereira Nunes Pinto
- Department of Evidence-Based Medicine, Brazilian Cochrane Centre, Federal University of São Paulo, Sao Paulo, Brazil.,Department of Biological and Health Sciences, Federal University of Amapá, Amapá, Brazil
| | - Vinicius Tassoni Civile
- Department of Evidence-Based Medicine, Brazilian Cochrane Centre, Federal University of São Paulo, Sao Paulo, Brazil.,Institute of Health Sciences, Paulista University, Sao Paulo, Brazil
| | - Fania Cristina Santos
- Department of Geriatrics and Gerontology, Federal University of São Paulo, Sao Paulo, Brazil
| | - Felipe Fregni
- Laboratory of Neuromodulation & Center for Clinical Research Learning, Physics and Rehabilitation Department, Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, MA, United States
| | - Virginia Fernandes Moça Trevisani
- Department of Evidence-Based Medicine, Brazilian Cochrane Centre, Federal University of São Paulo, Sao Paulo, Brazil.,Department of Rheumatology, Santo Amaro University, Sao Paulo, Brazil
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Abstract
Transcranial direct current stimulation (tDCS) modulates spontaneous neuronal activity that can generate long-term neuroplastic changes. It has been used in numerous therapeutic trials showing significant clinical effects especially when combined with other behavioral therapies. One area of intensive tDCS research is chronic pain. Since the initial tDCS trials for chronic pain treatment using current parameters of stimulation, more than 60 clinical trials have been published testing its effects in different pain syndromes. However, as the field moves in the direction of clinical application, several aspects need to be taken into consideration regarding tDCS effectiveness and parameters of stimulation. In this article, we reviewed the evidence of tDCS effects for the treatment of chronic pain and critically analyzed the literature pertaining its safety and efficacy, and how to optimize tDCS clinical effects in a therapeutic setting. We discuss optimization of tDCS effects in 3 different domains: (i) parameters of stimulation, (ii) combination therapies, and (iii) subject selection. This article aims to provide insights for the development of future tDCS clinical trials.
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Affiliation(s)
- Camila Bonin Pinto
- Laboratory of Neuromodulation & Center for Clinical Research Learning, Department of Physical Medicine and Rehabilitation, Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA, USA
| | - Beatriz Teixeira Costa
- Laboratory of Neuromodulation & Center for Clinical Research Learning, Department of Physical Medicine and Rehabilitation, Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA, USA
| | - Dante Duarte
- Laboratory of Neuromodulation & Center for Clinical Research Learning, Department of Physical Medicine and Rehabilitation, Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA, USA
| | - Felipe Fregni
- Laboratory of Neuromodulation & Center for Clinical Research Learning, Department of Physical Medicine and Rehabilitation, Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA, USA
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40
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Hoegh M, Petersen K, Graven-Nielsen T. Effects of repeated conditioning pain modulation in healthy volunteers. Eur J Pain 2018; 22:1833-1843. [DOI: 10.1002/ejp.1279] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/24/2018] [Indexed: 01/07/2023]
Affiliation(s)
- M. Hoegh
- Center for Neuroplasticity and Pain (CNAP), SMI; Aalborg University; Denmark
| | - K.K. Petersen
- Center for Neuroplasticity and Pain (CNAP), SMI; Aalborg University; Denmark
| | - T. Graven-Nielsen
- Center for Neuroplasticity and Pain (CNAP), SMI; Aalborg University; Denmark
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Hughes SW, Ali M, Sharma P, Insan N, Strutton PH. Frequency-dependent top-down modulation of temporal summation by anodal transcranial direct-current stimulation of the primary motor cortex in healthy adults. Eur J Pain 2018; 22:1494-1501. [PMID: 29704875 DOI: 10.1002/ejp.1238] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/22/2018] [Indexed: 02/28/2024]
Abstract
BACKGROUND Transcranial direct-current stimulation (tDCS) applied over the primary motor cortex has been shown to be effective in the treatment of a number of chronic pain conditions. However, there is a lack of understanding of the top-down analgesic mechanisms involved. METHOD In this study, we investigated the effects of tDCS on the facilitation of subjective sensory and pain scores using a transcutaneous electrically evoked measure of temporal summation. In this randomized, blinded, cross-over study healthy subjects received a single stimulus given at 0.9× pain threshold (pTh) over the L5 dermatome on the lateral aspect of the right leg, followed by a train of 5 stimuli given at 0.5, 1, 5 and 20 Hz before and after 20 min of sham or anodal tDCS (2 mA) applied over the primary motor cortex. Ratings of sensation and pain intensity were scored on a visual analogue scale (VAS). RESULTS Temporal summation leading to pain only occurred at higher frequencies (5 and 20 Hz). Sham or real tDCS had no effect over temporal summation evoked at 5 Hz; however, there was a significant analgesic effect at 20 Hz. Sham or real tDCS had no effect over acute, single stimuli-evoked responses. CONCLUSION These results indicate that anodal tDCS applied to the primary motor cortex preferentially modulates temporal summation induced by high-frequency electrical stimulation-induced pain. The inhibitory effects of tDCS appear to be dynamic and dependent on the degree of spinal cord excitability and may explain the higher analgesic efficacy in patients with moderate to severe chronic pain symptoms. SIGNIFICANCE The analgesic effects of tDCS are dependent on spinal cord excitability. This work provides insight into top-down modulation during acute pain and temporal summation. This knowledge may explain why tDCS has a higher analgesic efficacy in chronic pain patients.
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Affiliation(s)
- S W Hughes
- Faculty of Medicine, The Nick Davey Laboratory, Imperial College London, London, UK
| | - M Ali
- Faculty of Medicine, The Nick Davey Laboratory, Imperial College London, London, UK
| | - P Sharma
- Faculty of Medicine, The Nick Davey Laboratory, Imperial College London, London, UK
| | - N Insan
- Faculty of Medicine, The Nick Davey Laboratory, Imperial College London, London, UK
| | - P H Strutton
- Faculty of Medicine, The Nick Davey Laboratory, Imperial College London, London, UK
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da Silva FTG, Browne RAV, Pinto CB, Saleh Velez FG, do Egito EST, do Rêgo JTP, da Silva MR, Dantas PMS, Fregni F. Transcranial direct current stimulation in individuals with spinal cord injury: Assessment of autonomic nervous system activity. Restor Neurol Neurosci 2017; 35:159-169. [PMID: 28282844 DOI: 10.3233/rnn-160685] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND We hypothesized in this study that transcranial direct current stimulation (tDCS) of primary motor cortex could exert top-down modulation over subcortical systems associated with autonomic control and thus be useful to revert some of the dysfunctional changes found in the autonomic nervous system (ANS) of subjects with spinal cord injuries (SCI). OBJECTIVE To explore the acute effect of tDCS on ANS indexed by Heart Rate Variability (HRV) in individuals with SCI and analyze whether this effect depends on the gender, degree, level and time of injury. METHODS In this randomized, placebo-controlled, crossover, double-blinded study, 18 adults with SCI (32.9±7.9 years old) were included; the intervention consisted of a single 12-minute session of active tDCS (anodal, 2 mA) and a control session of sham tDCS applied over Cz (bihemispheric motor cortex). HRV was calculated using spectral analysis. Low-frequency (LF), high-frequency (HF), and LF/HF ratio variables were evaluated before, during, and post tDCS. RESULTS A two-way repeated measures ANOVA showed that after active (anodal) stimulation, LF/HF ratio was significantly increased (P = 0.013). There was a trend for an interaction between time and stimulation for both LF and HF (P = 0.052). Paired exploratory t-tests reported effects on the difference of time [post-pre] between stimulation conditions for LF (P = 0.052), HF (P = 0.052) and LF/HF (P = 0.003). CONCLUSION Anodal tDCS of the motor cortex modulated ANS activity in individuals with SCI independent of gender, type and time of lesion. These changes were in the direction of normalization of ANS parameters, thus confirming our initial hypothesis that an enhancement of cortical excitability by tDCS could at least partially restore some of the dysfunctional activity in the ANS system of subjects with SCI.
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Affiliation(s)
- Fabiana Tenório Gomes da Silva
- Laboratory of Neuromodulation, Center of Clinical Research Learning, Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, MA, USA.,Psychology institute, Department of Neurosciences and behavior, University of São Paulo (USP), São Paulo, Brazil.,Department of Physical Education, Health Sciences Center, Federal University of Rio Grande do Norte (UFRN), Natal, Rio Grande do Norte, Brazil
| | - Rodrigo Alberto Vieira Browne
- Department of Physical Education, Health Sciences Center, Federal University of Rio Grande do Norte (UFRN), Natal, Rio Grande do Norte, Brazil
| | - Camila Bonin Pinto
- Laboratory of Neuromodulation, Center of Clinical Research Learning, Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, MA, USA
| | - Faddi Ghassan Saleh Velez
- Laboratory of Neuromodulation, Center of Clinical Research Learning, Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, MA, USA
| | - Eryvaldo Sócrates Tabosa do Egito
- Department of Pharmacy, Health Sciences Center, Federal University of Rio Grande do Norte (UFRN), Natal, Rio Grande do Norte, Brazil
| | - Jeferson Tafarel Pereira do Rêgo
- Department of Physical Education, Health Sciences Center, Federal University of Rio Grande do Norte (UFRN), Natal, Rio Grande do Norte, Brazil
| | - Marília Rodrigues da Silva
- Department of Physical Education, Health Sciences Center, Federal University of Rio Grande do Norte (UFRN), Natal, Rio Grande do Norte, Brazil
| | - Paulo Moreira Silva Dantas
- Department of Physical Education, Health Sciences Center, Federal University of Rio Grande do Norte (UFRN), Natal, Rio Grande do Norte, Brazil
| | - Felipe Fregni
- Laboratory of Neuromodulation, Center of Clinical Research Learning, Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, MA, USA
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Flood A, Waddington G, Keegan RJ, Thompson KG, Cathcart S. The effects of elevated pain inhibition on endurance exercise performance. PeerJ 2017; 5:e3028. [PMID: 28265507 PMCID: PMC5337081 DOI: 10.7717/peerj.3028] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 01/25/2017] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The ergogenic effects of analgesic substances suggest that pain perception is an important regulator of work-rate during fatiguing exercise. Recent research has shown that endogenous inhibitory responses, which act to attenuate nociceptive input and reduce perceived pain, can be increased following transcranial direct current stimulation of the hand motor cortex. Using high-definition transcranial direct current stimulation (HD-tDCS; 2 mA, 20 min), the current study aimed to examine the effects of elevated pain inhibitory capacity on endurance exercise performance. It was hypothesised that HD-tDCS would enhance the efficiency of the endogenous pain inhibitory response and improve endurance exercise performance. METHODS Twelve healthy males between 18 and 40 years of age (M = 24.42 ± 3.85) were recruited for participation. Endogenous pain inhibitory capacity and exercise performance were assessed before and after both active and sham (placebo) stimulation. The conditioned pain modulation protocol was used for the measurement of pain inhibition. Exercise performance assessment consisted of both maximal voluntary contraction (MVC) and submaximal muscular endurance performance trials using isometric contractions of the non-dominant leg extensors. RESULTS Active HD-tDCS (pre-tDCS, -.32 ± 1.33 kg; post-tDCS, -1.23 ± 1.21 kg) significantly increased pain inhibitory responses relative to the effects of sham HD-tDCS (pre-tDCS, -.91 ± .92 kg; post-tDCS, -.26 ± .92 kg; p = .046). Irrespective of condition, peak MVC force and muscular endurance was reduced from pre- to post-stimulation. HD-tDCS did not significantly influence this reduction in maximal force (active: pre-tDCS, 264.89 ± 66.87 Nm; post-tDCS, 236.33 ± 66.51 Nm; sham: pre-tDCS, 249.25 ± 88.56 Nm; post-tDCS, 239.63 ± 67.53 Nm) or muscular endurance (active: pre-tDCS, 104.65 ± 42.36 s; post-tDCS, 93.07 ± 33.73 s; sham: pre-tDCS, 123.42 ± 72.48 s; post-tDCS, 100.27 ± 44.25 s). DISCUSSION Despite increasing pain inhibitory capacity relative to sham stimulation, active HD-tDCS did not significantly elevate maximal force production or muscular endurance. These findings question the role of endogenous pain inhibitory networks in the regulation of exercise performance.
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Affiliation(s)
- Andrew Flood
- Research Institute for Sport & Exercise, University of Canberra, Bruce, Australian Capital Territory, Australia; Centre for Applied Psychology, University of Canberra, Bruce, Australian Capital Territory, Australia
| | - Gordon Waddington
- Research Institute for Sport & Exercise, University of Canberra , Bruce , Australian Capital Territory , Australia
| | - Richard J Keegan
- Research Institute for Sport & Exercise, University of Canberra , Bruce , Australian Capital Territory , Australia
| | - Kevin G Thompson
- Research Institute for Sport & Exercise, University of Canberra , Bruce , Australian Capital Territory , Australia
| | - Stuart Cathcart
- Research Institute for Sport & Exercise, University of Canberra, Bruce, Australian Capital Territory, Australia; Centre for Applied Psychology, University of Canberra, Bruce, Australian Capital Territory, Australia
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Flood A, Waddington G, Thompson K, Cathcart S. Increased conditioned pain modulation in athletes. J Sports Sci 2016; 35:1066-1072. [DOI: 10.1080/02640414.2016.1210196] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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45
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Alam M, Truong DQ, Khadka N, Bikson M. Spatial and polarity precision of concentric high-definition transcranial direct current stimulation (HD-tDCS). Phys Med Biol 2016; 61:4506-21. [DOI: 10.1088/0031-9155/61/12/4506] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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46
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Cancelli A, Cottone C, Tecchio F, Truong DQ, Dmochowski J, Bikson M. A simple method for EEG guided transcranial electrical stimulation without models. J Neural Eng 2016; 13:036022. [PMID: 27172063 DOI: 10.1088/1741-2560/13/3/036022] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
OBJECTIVE There is longstanding interest in using EEG measurements to inform transcranial Electrical Stimulation (tES) but adoption is lacking because users need a simple and adaptable recipe. The conventional approach is to use anatomical head-models for both source localization (the EEG inverse problem) and current flow modeling (the tES forward model), but this approach is computationally demanding, requires an anatomical MRI, and strict assumptions about the target brain regions. We evaluate techniques whereby tES dose is derived from EEG without the need for an anatomical head model, target assumptions, difficult case-by-case conjecture, or many stimulation electrodes. APPROACH We developed a simple two-step approach to EEG-guided tES that based on the topography of the EEG: (1) selects locations to be used for stimulation; (2) determines current applied to each electrode. Each step is performed based solely on the EEG with no need for head models or source localization. Cortical dipoles represent idealized brain targets. EEG-guided tES strategies are verified using a finite element method simulation of the EEG generated by a dipole, oriented either tangential or radial to the scalp surface, and then simulating the tES-generated electric field produced by each model-free technique. These model-free approaches are compared to a 'gold standard' numerically optimized dose of tES that assumes perfect understanding of the dipole location and head anatomy. We vary the number of electrodes from a few to over three hundred, with focality or intensity as optimization criterion. MAIN RESULTS Model-free approaches evaluated include (1) voltage-to-voltage, (2) voltage-to-current; (3) Laplacian; and two Ad-Hoc techniques (4) dipole sink-to-sink; and (5) sink to concentric. Our results demonstrate that simple ad hoc approaches can achieve reasonable targeting for the case of a cortical dipole, remarkably with only 2-8 electrodes and no need for a model of the head. SIGNIFICANCE Our approach is verified directly only for a theoretically localized source, but may be potentially applied to an arbitrary EEG topography. For its simplicity and linearity, our recipe for model-free EEG guided tES lends itself to broad adoption and can be applied to static (tDCS), time-variant (e.g., tACS, tRNS, tPCS), or closed-loop tES.
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Affiliation(s)
- Andrea Cancelli
- Laboratory of Electrophysiology for Translational neuroScience (LET'S)-ISTC-CNR, Italy. Institute of Neurology, Catholic University, Rome, Italy
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