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Di Lazzaro V, Ranieri F, Bączyk M, de Carvalho M, Dileone M, Dubbioso R, Fernandes S, Kozak G, Motolese F, Ziemann U. Novel approaches to motoneuron disease/ALS treatment using non-invasive brain and spinal stimulation: IFCN handbook chapter. Clin Neurophysiol 2024; 158:114-136. [PMID: 38218077 DOI: 10.1016/j.clinph.2023.12.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 11/28/2023] [Accepted: 12/17/2023] [Indexed: 01/15/2024]
Abstract
Non-invasive brain stimulation techniques have been exploited in motor neuron disease (MND) with multifold objectives: to support the diagnosis, to get insights in the pathophysiology of these disorders and, more recently, to slow down disease progression. In this review, we consider how neuromodulation can now be employed to treat MND, with specific attention to amyotrophic lateral sclerosis (ALS), the most common form with upper motoneuron (UMN) involvement, taking into account electrophysiological abnormalities revealed by human and animal studies that can be targeted by neuromodulation techniques. This review article encompasses repetitive transcranial magnetic stimulation methods (including low-frequency, high-frequency, and pattern stimulation paradigms), transcranial direct current stimulation as well as experimental findings with the newer approach of trans-spinal direct current stimulation. We also survey and discuss the trials that have been performed, and future perspectives.
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Affiliation(s)
- Vincenzo Di Lazzaro
- Department of Medicine and Surgery, Unit of Neurology, Neurophysiology, Neurobiology and Psychiatry, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo, 21, 00128 Roma, Italy; Fondazione Policlinico Universitario Campus Bio-Medico, Via Alvaro del Portillo, 200, 00128 Roma, Italy.
| | - Federico Ranieri
- Neurology Unit, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, P.Le L.A. Scuro 10, 37134 Verona, Italy
| | - Marcin Bączyk
- Department of Neurobiology, Poznań University of Physical Education, Królowej Jadwigi Street 27/39, 61-871 Poznań, Poland
| | - Mamede de Carvalho
- Institute of Physiology, Institute of Molecular Medicine-JLA, Egas Moniz Study Centre, Faculty of Medicine, University of Lisbon, Lisbon 1649-028, Portugal; Department of Neurosciences and Mental Health, CHULN, Lisbon, Portugal
| | - Michele Dileone
- Faculty of Health Sciences, UCLM Talavera de la Reina, Toledo, Spain; Neurology Department, Hospital Nuestra Señora del Prado, Talavera de la Reina, Toledo, Spain
| | - Raffaele Dubbioso
- Neurophysiology Unit, Department of Neurosciences, Reproductive Sciences and Odontostomatology, University of Naples "Federico II", Napoli, Italy
| | - Sofia Fernandes
- Instituto de Biofísica e Engenharia Biomédica, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016-Lisboa, Portugal
| | - Gabor Kozak
- Department of Neurology and Stroke, University of Tübingen, Tübingen, Germany; Hertie-Institute of Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Francesco Motolese
- Fondazione Policlinico Universitario Campus Bio-Medico, Via Alvaro del Portillo, 200, 00128 Roma, Italy
| | - Ulf Ziemann
- Department of Neurology and Stroke, University of Tübingen, Tübingen, Germany; Hertie-Institute of Clinical Brain Research, University of Tübingen, Tübingen, Germany.
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Popyvanova A, Pomelova E, Bredikhin D, Koriakina M, Shestakova A, Blagovechtchenski E. Transspinal Direct Current Electrical Stimulation Selectively Affects the Excitability of the Corticospinal System, Depending on the Intensity but Not Motor Skills. Life (Basel) 2023; 13:2353. [PMID: 38137954 PMCID: PMC10744344 DOI: 10.3390/life13122353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 12/10/2023] [Accepted: 12/11/2023] [Indexed: 12/24/2023] Open
Abstract
Transspinal direct current stimulation (tsDCS) is a non-invasive technique used to modulate spinal cord activity. However, the effects and mechanisms of this stimulation are currently not comprehensively known. This study aimed to estimate the effect of different intensities of tsDCS applied at the level of cervical enlargement of the spinal cord (C7-Th1 segments) on the excitability of the corticospinal system (CSS) and the correction of motor skills in healthy subjects. The effect of tsDCS was estimated by the motor-evoked potentials (MEP) elicited by transcranial magnetic stimulation (TMS) in the primary motor cortex (M1). The study involved 54 healthy adults aged 22 ± 4 years. The application of 11 min anodal tsDCS at the level of the cervical spine C7-Th1 with a current intensity of 2.5 mA did not change the MEP amplitude of the upper limb muscles, in contrast to the data that we previously obtained with a current intensity of 1.5 mA. We also found no difference in the effect of 2.5 mA stimulation on motor skill correction in healthy subjects in the nine-hole peg test (9-HPT) and the serial reaction time task (SRT) as with 1.5 mA stimulation. Our data show that an increase in the intensity of stimulation does not lead to an increase in the effects but rather reduces the effects of stimulation. These results provide information about the optimally appropriate stimulation current intensities to induce CSS excitability and the ability of tsDCS to influence motor skills in healthy adults.
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Affiliation(s)
| | | | | | | | | | - Evgeny Blagovechtchenski
- Centre for Cognition and Decision Making, Institute for Cognitive Neuroscience, HSE University, 101000 Moscow, Russia; (A.P.); (E.P.); (D.B.); (M.K.); (A.S.)
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Hassan AB, Salihu AT, Masta MA, Gunn H, Marsden J, Abdullahi A, Ahmad RY, Danazumi MS. Effect of transcutaneous spinal direct current stimulation on spasticity in upper motor neuron conditions: a systematic review and meta-analysis. Spinal Cord 2023; 61:587-599. [PMID: 37640926 DOI: 10.1038/s41393-023-00928-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 08/02/2023] [Accepted: 08/16/2023] [Indexed: 08/31/2023]
Abstract
STUDY DESIGN A systematic review and meta-analysis of clinical trials. OBJECTIVES To determine the effect of non-invasive transcutaneous spinal direct current stimulation (tsDCS) on spasticity, activity limitations and participation restrictions in various upper motor neuron diseases. METHODS Six databases including CINAHL plus, Cochrane CENTRAL, Embase, MEDLINE, SCOPUS and Web of Science were searched for the relevant records from January 2008 to December 2022. Two reviewers independently selected and extracted data on spasticity, activity limitations and participation restrictions. The risk of bias was evaluated using the PEDro scale while the GRADE approach established the certainty of the evidence. RESULTS Eleven studies were identified of which 5 (45.5%) were rated as having a low risk of bias and 8 (72.7%) were meta-analyzed. The meta-analyses did not show any significant differences between cathodal (SMD = -0.67, 95% CI = -1.50 to 0.15, P = 0.11, I2 = 75%, 6 RCTs) or anodal (SMD = 0.11, 95% CI = -0.43 to -0.64, p = 0.69, I2 = 0%, 2 RCTs) and sham tsDCS for spasticity. There was also no significant difference between active and sham tsDCS for activity limitations (SMD = -0.42, 95% CI = -0.04 to 0.21, p = 0.2, I2 = 0%, 2 RCTs) and participation restrictions (MD = -8.10, 95% CI = -18.02 to 1.82, p = 0.11, 1 RCT). CONCLUSIONS The meta-analysis of the available evidence provides an uncertain estimate of the effect of cathodal tsDCS on spasticity, activity limitation and participation restriction. It might be very helpful, or it may make no difference at all. However, considering the level of the evidence and the limitation in the quality of the majority of the included studies, further well-designed research may likely change the estimate of effect. TRIAL REGISTRATION PROSPERO CRD42021245601.
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Affiliation(s)
- Auwal B Hassan
- Department of Medical Rehabilitation (Physiotherapy), Faculty of Allied Health Sciences, College of Medical Sciences, University of Maiduguri, Maiduguri, Borno State, Nigeria
| | - Abubakar T Salihu
- Department of Physiotherapy, Monash University, Melbourne, VIC, Australia
| | - Mamman A Masta
- Department of Medical Rehabilitation (Physiotherapy), Faculty of Allied Health Sciences, College of Medical Sciences, University of Maiduguri, Maiduguri, Borno State, Nigeria
| | - Hilary Gunn
- Peninsula Allied Health Centre, University of Plymouth, Plymouth, UK
| | - Jonathan Marsden
- Peninsula Allied Health Centre, University of Plymouth, Plymouth, UK
| | - Auwal Abdullahi
- Department of Physiotherapy, Bayero University Kano, Kano, Nigeria
| | - Rufa'i Y Ahmad
- Department of Physiotherapy, Bayero University Kano, Kano, Nigeria
| | - Musa S Danazumi
- Discipline of Physiotherapy, School of Allied Health, Human Services and Sport, College of Sciences, Health and Engineering, La Trobe University, Bundoora, VIC, 3085, Australia.
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Fava de Lima F, Silva CR, Kohn AF. Transcutaneous spinal direct current stimulation (tsDCS) does not affect postural sway of young and healthy subjects during quiet upright standing. PLoS One 2022; 17:e0267718. [PMID: 35482798 PMCID: PMC9049532 DOI: 10.1371/journal.pone.0267718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 04/13/2022] [Indexed: 12/02/2022] Open
Abstract
Transcutaneous spinal direct current stimulation (tsDCS) is an effective non-invasive spinal cord electrical stimulation technique to induce neuromodulation of local and distal neural circuits of the central nervous system (CNS). Applied to the spinal cord lumbosacral region, tsDCS changes electrophysiological responses of the motor, proprioceptive and nociceptive pathways, alters the performance of some lower limb motor tasks and can even modulate the behavior of supramedullary neuronal networks. In this study an experimental protocol was conducted to verify if tsDCS (5 mA, 20 minutes) of two different polarizations, applied over the lumbosacral region (tenth thoracic vertebrae (T10)), can induce changes in postural sway oscillations of young healthy individuals during quiet standing. A novel initialization of the electrical stimulation was developed to improve subject blinding to the different stimulus conditions including the sham trials. Measures of postural sway, both global and structural, were computed before, during and following the DC stimulation period. The results indicated that, for the adopted conditions, tsDCS did not induce statistically significant changes in postural sway of young healthy individuals during quiet standing.
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Affiliation(s)
- Felipe Fava de Lima
- Biomedical Engineering Laboratory, Escola Politécnica, University of São Paulo, São Paulo, Brazil
- * E-mail:
| | - Cristiano Rocha Silva
- Biomedical Engineering Laboratory, Escola Politécnica, University of São Paulo, São Paulo, Brazil
| | - Andre Fabio Kohn
- Biomedical Engineering Laboratory, Escola Politécnica, University of São Paulo, São Paulo, Brazil
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Finn HT, Bogdanovski O, Hudson AL, McCaughey EJ, Crawford MR, Taylor JL, Butler JE, Gandevia SC. The effect of acute intermittent hypoxia on human limb motoneurone output. Exp Physiol 2022; 107:615-630. [PMID: 35338753 DOI: 10.1113/ep090099] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Accepted: 03/17/2022] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Does a single session of repeated bouts of acute intermittent hypoxic breathing enhance the motoneuronal output of the limb muscles of healthy able-bodied participants? What is the main finding and its importance? Compared to breathing room air, there were some increases in motoneuronal output following acute intermittent hypoxia, but the increases were variable across participants, in time after the intervention and depended on which neurophysiological measure was checked. ABSTRACT Acute intermittent hypoxia (AIH) induces persistent increases in output from rat phrenic motoneurones. Studies in people with spinal cord injury suggest AIH improves limb performance, perhaps via postsynaptic changes at cortico-motoneuronal synapses. We assessed whether limb motoneurone output in response to reflex and descending synaptic activation is facilitated after one session of AIH in healthy able-bodied volunteers. Fourteen participants completed two experimental days, either AIH or a sham intervention (randomised crossover design). We measured H-reflex recruitment curves and homosynaptic post-activation depression (HPAD) of the H reflex in soleus, and motor evoked potentials (MEPs) evoked by transcranial magnetic stimulation (TMS) and their recruitment curves, in first dorsal interosseous. All measurements were performed at rest and occurred at baseline, 0, 20, 40, and 60 minutes post-intervention. The intervention was 30 minutes of either normoxia (sham, FiO2 ≈ 0.21) or AIH (alternate 1-minute hypoxia [FiO2 ≈ 0.09], 1-minute normoxia). After AIH the H-reflex recruitment curve shifted leftward. Lower stimulation intensities were needed to evoke 5%, 50%, and 99% of the maximal H reflex at 40 and 60 minutes after AIH (P<0.04). The maximal H reflex, recruitment slope and HPAD, were unchanged after AIH. MEPs evoked by constant intensity TMS were larger 40 minutes after AIH (P = 0.027). There was no change in MEP recruitment or the maximal MEP. In conclusion, some measures of the evoked responses from limb motoneurones increased after a single AIH session, but only at discrete time points. It is unclear to what extent these changes alter functional performance. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Harrison T Finn
- Neuroscience Research Australia, Sydney, NSW, 2031, Australia.,University of New South Wales, Sydney, NSW, 2052, Australia
| | - Oliver Bogdanovski
- Neuroscience Research Australia, Sydney, NSW, 2031, Australia.,University of New South Wales, Sydney, NSW, 2052, Australia
| | - Anna L Hudson
- Neuroscience Research Australia, Sydney, NSW, 2031, Australia.,University of New South Wales, Sydney, NSW, 2052, Australia.,College of Medicine and Public Health, Flinders University, Bedford Park, South Australia, 5042, Australia
| | - Euan J McCaughey
- Neuroscience Research Australia, Sydney, NSW, 2031, Australia.,University of New South Wales, Sydney, NSW, 2052, Australia
| | | | - Janet L Taylor
- Neuroscience Research Australia, Sydney, NSW, 2031, Australia.,Edith Cowan University, Perth, WA, 6027, Australia
| | - Jane E Butler
- Neuroscience Research Australia, Sydney, NSW, 2031, Australia.,University of New South Wales, Sydney, NSW, 2052, Australia
| | - Simon C Gandevia
- Neuroscience Research Australia, Sydney, NSW, 2031, Australia.,University of New South Wales, Sydney, NSW, 2052, Australia
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6
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Effects of paired stimulation with specific waveforms on cortical and spinal plasticity in subjects with a chronic spinal cord injury. J Formos Med Assoc 2022; 121:2044-2056. [DOI: 10.1016/j.jfma.2022.02.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 12/13/2021] [Accepted: 02/17/2022] [Indexed: 12/16/2022] Open
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Sham-derived effects and the minimal reliability of theta burst stimulation. Sci Rep 2021; 11:21170. [PMID: 34707206 PMCID: PMC8551312 DOI: 10.1038/s41598-021-98751-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 08/20/2021] [Indexed: 11/16/2022] Open
Abstract
Theta-burst stimulation (TBS) is a patterned form of repetitive transcranial magnetic stimulation (rTMS) that has been used to induce long-term modulation (plasticity) of corticospinal excitability in a drastically shorter duration protocol than conventional rTMS protocols. In this study we tested the reliability of the effects of two well defined TBS protocols, continuous TBS (cTBS) and intermittent TBS (iTBS), especially in relation to sham TBS, within and across the same 24 participants. All TBS protocols were repeated after approximately 1 month to assess the magnitude and reliability of the modulatory effects of each TBS protocol. Baseline and post-TBS changes in motor evoked potentials (MEP—measure of corticospinal excitability) amplitudes were compared across the cTBS, iTBS and sham TBS protocols and between the initial and retest visits. Overall, across participants, at the initial visit, iTBS facilitated MEPs as compared to baseline excitability, with sham eliciting the same effect. cTBS did not show a significant suppression of excitability compared to baseline MEPs at either visit, and even facilitated MEPs above baseline excitability at a single time point during the repeat visit. Otherwise, effects of TBS were generally diminished in the repeat visit, with iTBS and sham TBS replicating facilitation of MEPs above baseline excitability at similar time points. However, no protocol demonstrated consistent intra-individual modulation of corticospinal excitability upon retest. As the first study to test both iTBS and cTBS against sham TBS across repeat visits, our findings challenge the efficacy and reliability of TBS protocols and emphasize the importance of accounting for sham effects of TBS. Furthermore, given that therapeutic effects of TBS are hypothetically derived from consistent and repeated modulation of brain activity, the non-replicability of plasticity and sham effects call into question these basic mechanisms.
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Therkildsen ER, Nielsen JB, Beck MM, Yamaguchi T, Lorentzen J. The effect of cathodal transspinal direct current stimulation on tibialis anterior stretch reflex components in humans. Exp Brain Res 2021; 240:159-171. [PMID: 34686909 DOI: 10.1007/s00221-021-06243-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 10/08/2021] [Indexed: 01/04/2023]
Abstract
Spinal DC stimulation (tsDCS) shows promise as a technique for the facilitation of functional recovery of motor function following central nervous system (CNS) lesion. However, the network mechanisms that are responsible for the effects of tsDCS are still uncertain. Here, in a series of experiments, we tested the hypothesis that tsDCS increases the excitability of the long-latency stretch reflex, leading to increased excitability of corticospinal neurons in the primary motor cortex. Experiments were performed in 33 adult human subjects (mean age 28 ± 7 years/14 females). Subjects were seated in a reclining armchair with the right leg attached to a footplate, which could be quickly plantarflexed (100 deg/s; 6 deg amplitude) to induce stretch reflexes in the tibialis anterior (TA) muscle at short (45 ms) and longer latencies (90-95 ms). This setup also enabled measuring motor evoked potentials (MEPs) and cervicomedullary evoked potentials (cMEPs) from TA evoked by transcranial magnetic stimulation (TMS) and electrical stimulation at the cervical junction, respectively. Cathodal tsDCS at 2.5 and 4 mA was found to increase the long-latency reflex without any significant effect on the short-latency reflex. Furthermore, TA MEPs, but not cMEPs, were increased following tsDCS. We conclude that cathodal tsDCS over lumbar segments may facilitate proprioceptive transcortical reflexes in the TA muscle, and we suggest that the most likely explanation of this facilitation is an effect on ascending fibers in the dorsal columns.
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Affiliation(s)
- Eva Rudjord Therkildsen
- Department of Neuroscience, Panum Institute 33.3, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark.
| | - Jens Bo Nielsen
- Department of Neuroscience, Panum Institute 33.3, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark.,Elsass Foundation, Holmegaardsvej 28, 2920, Charlottenlund, Denmark
| | - Mikkel Malling Beck
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Nørre Allé 51, 2200, Copenhagen, Denmark
| | - Tomofumi Yamaguchi
- Department of Neuroscience, Panum Institute 33.3, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark.,Department of Physical Therapy, Faculty of Health Science, Juntendo University, 2-1-1Bunkyo-ku, HongoTokyo, Japan
| | - Jakob Lorentzen
- Department of Neuroscience, Panum Institute 33.3, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen, Denmark
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Lockyer EJ, Compton CT, Forman DA, Pearcey GE, Button DC, Power KE. Moving forward: methodological considerations for assessing corticospinal excitability during rhythmic motor output in humans. J Neurophysiol 2021; 126:181-194. [PMID: 34133230 DOI: 10.1152/jn.00027.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The use of transcranial magnetic stimulation to assess the excitability of the central nervous system to further understand the neural control of human movement is expansive. The majority of the work performed to-date has assessed corticospinal excitability either at rest or during relatively simple isometric contractions. The results from this work are not easily extrapolated to rhythmic, dynamic motor outputs, given that corticospinal excitability is task-, phase-, intensity-, direction-, and muscle-dependent (Power KE, Lockyer EJ, Forman DA, Button DC. Appl Physiol Nutr Metab 43: 1176-1185, 2018). Assessing corticospinal excitability during rhythmic motor output, however, involves technical challenges that are to be overcome, or at the minimum considered, when attempting to design experiments and interpret the physiological relevance of the results. The purpose of this narrative review is to highlight the research examining corticospinal excitability during a rhythmic motor output and, importantly, to provide recommendations regarding the many factors that must be considered when designing and interpreting findings from studies that involve limb movement. To do so, the majority of work described herein refers to work performed using arm cycling (arm pedaling or arm cranking) as a model of a rhythmic motor output used to examine the neural control of human locomotion.
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Affiliation(s)
- Evan J Lockyer
- Human Neurophysiology Lab, School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada.,Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Chris T Compton
- Human Neurophysiology Lab, School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada.,Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Davis A Forman
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Gregory E Pearcey
- Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, Illinois.,Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois.,Shirley Ryan Ability Lab, Chicago, Illinois
| | - Duane C Button
- Human Neurophysiology Lab, School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada.,Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Kevin E Power
- Human Neurophysiology Lab, School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada.,Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
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Ciccone AB, Fry AC, Emerson DM, Gallagher PM, Herda TJ, Weir JP. Effects of Transspinal Direct Current Stimulation on Cycling Perception of Effort and Time to Exhaustion. J Strength Cond Res 2021; 35:347-352. [PMID: 33306592 DOI: 10.1519/jsc.0000000000003876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
ABSTRACT Ciccone, AB, Fry, AC, Emerson, DM, Gallagher, PM, Herda, TJ, and Weir, JP. Effects of transspinal direct current stimulation on cycling perception of effort and time to exhaustion. J Strength Cond Res 35(2): 347-352, 2021-In the past decade, researchers have investigated the efficacy of transspinal direct current stimulation (tsDCS) on the central nervous system and afferent neuron function in humans. Recently, data have suggested it may be possible for such tsDCS-induced changes in neuromuscular function to enhance performance. This study used noninvasive thoracic spine tsDCS to determine if cycling performance and perception of effort could be modulated by tsDCS. In 3 different stimulation conditions, anodal, cathodal, and sham, subjects cycled at 80% of their maximal aerobic capacity until exhaustion and reported their rating of perceived exertion (RPE) every minute. From this period, we compared the RPE responses over the first 3 minutes and time to exhaustion. There was no significant difference in time to exhaustion between anodal (408 ± 121 seconds), cathodal (413 ± 168 seconds), and sham (440 ± 189 seconds) conditions (p = 0.58). There was no significant difference in RPE from minutes 1-3 (collapsed across time) between anodal (12.9 ± 2.4 arbitrary units (AUs)), cathodal (13.3 ± 2.2 AUs), and sham (12.9 ± 2.1 AUs) conditions (p = 0.51). These data suggest tsDCS condition did not influence cycling performance or perception of effort during high-intensity cycling. Therefore, thoracic spine and lower abdominal montage delivering a current density of 0.071 mA·cm-2 for 20 minutes likely does not substantially improve high-intensity cycling work capacity. Therefore, more research is needed to investigate the efficacy of tsDCS and which stimulation methods may and may not enhance human performance.
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Affiliation(s)
- Anthony B Ciccone
- Department of Exercise Science and Outdoor Recreation, Utah Valley University, Orem, Utah; and
| | - Andrew C Fry
- Osness Human Performance Laboratories, Department of Health, Sport, and Exercise Sciences, University of Kansas, Lawrence, Kansas
| | - Dawn M Emerson
- Osness Human Performance Laboratories, Department of Health, Sport, and Exercise Sciences, University of Kansas, Lawrence, Kansas
| | - Philip M Gallagher
- Osness Human Performance Laboratories, Department of Health, Sport, and Exercise Sciences, University of Kansas, Lawrence, Kansas
| | - Trent J Herda
- Osness Human Performance Laboratories, Department of Health, Sport, and Exercise Sciences, University of Kansas, Lawrence, Kansas
| | - Joseph P Weir
- Osness Human Performance Laboratories, Department of Health, Sport, and Exercise Sciences, University of Kansas, Lawrence, Kansas
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Cortical and Subcortical Neural Interactions Between Trunk and Upper-limb Muscles in Humans. Neuroscience 2020; 451:126-136. [PMID: 33075460 DOI: 10.1016/j.neuroscience.2020.10.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Revised: 10/01/2020] [Accepted: 10/05/2020] [Indexed: 12/28/2022]
Abstract
Activities of daily living require simultaneous and coordinated activation of trunk and upper-limb segments, which involves complex interlimb interaction within the central nervous system. Although many studies have reported associations between activity of trunk and limb muscles during functional tasks, evidence on cortical and subcortical contributions to trunk-limb neural interactions is still not fully clear. Therefore, the aim of this study was to examine interactions between trunk and upper-limb muscles in the: (i) corticospinal circuits by using motor evoked potential (MEP) elicited through transcranial magnetic stimulation; and (ii) subcortical circuits by using cervicomedullary motor evoked potential (CMEP) elicited through cervicomedullary junction magnetic stimulation. Responses were evoked in the erector spinae (trunk) and flexor carpi radialis (upper-limb) muscles in twelve able-bodied individuals: (1) while participants were relaxed; (2) during trunk muscle contractions while arms were at rest; and (3) during upper-limb muscle contractions while the trunk was at rest. Our results showed that trunk muscle CMEP responses were not affected by upper-limb muscle contractions, while MEP responses were modulated. This indicates that at least the subcortical circuits may not attribute to facilitation of the trunk muscles during upper-limb contractions. On the other hand, in the upper-limb muscles, both CMEP and MEP responses were modulated during trunk contractions. These results indicate that cortical and subcortical mechanisms attributed to facilitation of upper-limb muscles during trunk contractions. In conclusion, our study demonstrated evidence that trunk-limb neural interactions may be attributed to cortical and/or subcortical mechanisms depending on the contracted muscle.
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12
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Wu YK, Levine JM, Wecht JR, Maher MT, LiMonta JM, Saeed S, Santiago TM, Bailey E, Kastuar S, Guber KS, Yung L, Weir JP, Carmel JB, Harel NY. Posteroanterior cervical transcutaneous spinal stimulation targets ventral and dorsal nerve roots. Clin Neurophysiol 2019; 131:451-460. [PMID: 31887616 DOI: 10.1016/j.clinph.2019.11.056] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 10/24/2019] [Accepted: 11/17/2019] [Indexed: 12/13/2022]
Abstract
OBJECTIVE We aim to non-invasively facilitate activation of spared neural circuits after cervical spinal cord injury (SCI) and amyotrophic lateral sclerosis (ALS). We developed and tested a novel configuration for cervical transcutaneous spinal stimulation (cTSS). METHODS cTSS was delivered via electrodes placed over the midline at ~T2-T4 levels posteriorly and ~C4-C5 levels anteriorly. Electromyographic responses were measured in arm and hand muscles across a range of stimulus intensities. Double-pulse experiments were performed to assess homosynaptic post-activation depression (PAD). Safety was closely monitored. RESULTS More than 170 cTSS sessions were conducted without major safety or tolerability issues. A cathode-posterior, 2 ms biphasic waveform provided optimal stimulation characteristics. Bilateral upper extremity muscle responses were easily obtained in subjects with SCI and ALS. Resting motor threshold at the abductor pollicis brevis muscle ranged from 5.5 to 51.0 mA. As stimulus intensity increased, response latencies to all muscles decreased. PAD was incomplete at lower stimulus intensities, and decreased at higher stimulus intensities. CONCLUSIONS Posteroanterior cTSS has the capability to target motor neurons both trans-synaptically via large-diameter afferents and non-synaptically via efferent motor axons. SIGNIFICANCE Posteroanterior cTSS is well tolerated and easily activates upper extremity muscles in individuals with SCI and ALS.
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Affiliation(s)
- Yu-Kuang Wu
- James J. Peters VA Medical Center, 130 West Kingsbridge Road, Bronx, NY 10468, USA; Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY 10029, USA
| | - Jonah M Levine
- James J. Peters VA Medical Center, 130 West Kingsbridge Road, Bronx, NY 10468, USA
| | - Jaclyn R Wecht
- James J. Peters VA Medical Center, 130 West Kingsbridge Road, Bronx, NY 10468, USA
| | - Matthew T Maher
- James J. Peters VA Medical Center, 130 West Kingsbridge Road, Bronx, NY 10468, USA
| | - James M LiMonta
- James J. Peters VA Medical Center, 130 West Kingsbridge Road, Bronx, NY 10468, USA
| | - Sana Saeed
- James J. Peters VA Medical Center, 130 West Kingsbridge Road, Bronx, NY 10468, USA
| | - Tiffany M Santiago
- James J. Peters VA Medical Center, 130 West Kingsbridge Road, Bronx, NY 10468, USA
| | - Eric Bailey
- James J. Peters VA Medical Center, 130 West Kingsbridge Road, Bronx, NY 10468, USA
| | - Shivani Kastuar
- Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY 10029, USA
| | - Kenneth S Guber
- James J. Peters VA Medical Center, 130 West Kingsbridge Road, Bronx, NY 10468, USA
| | - Lok Yung
- James J. Peters VA Medical Center, 130 West Kingsbridge Road, Bronx, NY 10468, USA
| | - Joseph P Weir
- University of Kansas, 1301 Sunnyside Avenue, Lawrence, KS 66045, USA
| | - Jason B Carmel
- Columbia University, 650 West 168th Street, New York, NY 10032, USA
| | - Noam Y Harel
- James J. Peters VA Medical Center, 130 West Kingsbridge Road, Bronx, NY 10468, USA; Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY 10029, USA.
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13
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Fernandes SR, Pereira M, Salvador R, Miranda PC, de Carvalho M. Cervical trans-spinal direct current stimulation: a modelling-experimental approach. J Neuroeng Rehabil 2019; 16:123. [PMID: 31653265 PMCID: PMC6815068 DOI: 10.1186/s12984-019-0589-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 09/06/2019] [Indexed: 11/18/2022] Open
Abstract
Background Trans-spinal direct current stimulation (tsDCS) is a non-invasive technique with promising neuromodulatory effects on spinal cord (SC) circuitry. Computational studies are essential to guide effective tsDCS protocols for specific clinical applications. This study aims to combine modelling and experimental studies to determine the electrode montage that maximizes electric field (E-field) delivery during cervical tsDCS. Methods Current and E-field distributions in the cervical SC were predicted for four electrode montages in a human realistic model using computational methods. A double-blind crossover and randomized exploratory study was conducted using the montage that maximized E-field delivery. tsDCS was applied for 15 min in 10 healthy subjects (anodal, cathodal, sham, with polarity assigned to the cervical electrode), with a current intensity of 2.5 mA, resulting in a total current charge density delivery of 90 mC/cm2. Upper limb motor (transcranial magnetic stimulation) and sensory evoked potentials (MEP, SEP), M-waves, H-reflex and F-wave responses were analysed. Central and peripheral conduction times were determined using MEP. Repeated measures ANOVA and Friedman test were used for statistical analysis (significance level α = 0.05). Results All montages presented higher current density and E-field magnitudes in the cervical SC region between the electrodes. However, electrodes at C3 and T3 spinous processes (C3-T3) originated the highest E-field magnitude (0.50 V/m). Using C3-T3 montage we observed significant changes in N9 SEP latency (p = 0.006), but significance did not persist in pairwise comparisons (sham-anodal: p = 0.022; sham-cathodal: p = 0.619; anodal-cathodal: p = 0.018; α = 0.017, Bonferroni corrected). MEP latency and central motor conduction time (CMCT) modified significantly on stimulation (p = 0.007 and p = 0.015, respectively). In addition, pairwise comparisons confirmed significant differences between sham and cathodal conditions after Bonferroni correction for MEP latency (sham-anodal: p = 0.868; sham-cathodal: p = 0.011; anodal-cathodal: p = 0.023) and CMCT (sham-anodal: p = 0.929; sham-cathodal: p = 0.010; anodal-cathodal: p = 0.034). Conclusions Computational models predicted higher E-field delivery in the cervical SC for the C3-T3 montage. Polarity-dependent effects in motor responses were reported using this montage consistent with spinal motor modulation. tsDCS experimental protocol designs should be guided by modelling studies to improve effectiveness.
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Affiliation(s)
- Sofia Rita Fernandes
- Instituto de Fisiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028, Lisbon, Portugal. .,Instituto de Biofísica e Engenharia Biomédica, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016, Lisbon, Portugal.
| | - Mariana Pereira
- Instituto de Fisiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028, Lisbon, Portugal
| | - Ricardo Salvador
- Neuroelectrics, Avinguda Tibidabo, 47 bis, 08035, Barcelona, Spain
| | - Pedro Cavaleiro Miranda
- Instituto de Biofísica e Engenharia Biomédica, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016, Lisbon, Portugal
| | - Mamede de Carvalho
- Instituto de Fisiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028, Lisbon, Portugal.,Departamento de Neurociências e Saúde Mental, Hospital de Santa Maria - Centro Hospitalar Lisboa Norte, Avenida Professor Egas Moniz, 1649-035, Lisbon, Portugal
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14
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Abstract
Respiratory failure is common during acute exacerbation of chronic obstructive pulmonary disease (AE-COPD). Phrenic nerve conduction (PNC), transcranial magnetic stimulation (TMS), and cervical magnetic stimulation (CMS) are of great value in identifying the feature and site of AE-COPD.PNC, TMS, and CMS were performed in 20 AE-COPD patients with respiratory failure, and re-examined after weaning. Latencies and amplitudes of the diaphragmatic compound muscle action potential (dCMAP), motor evoked potential of the diaphragm (dMEP) evoked by TMS and CMS, and central motor conduction time (CMCT) were measured. Blood gas analysis and serum electrolyte levels were also evaluated. The results were compared with those from 20 healthy subjects.AE-COPD patients showed prolonged CMCT and latencies of dCMAP and dMEP, decreased amplitudes of dCMAP and dMEP evoked by CMS, while CMCT and the latency of dMEP evoked by TMS were shortened after weaning. Significant correlation was identified between arterial blood gas analysis, serum electrolyte levels, disease duration, the duration of mechanical ventilation and the electrophysiological findings in AE-COPD patients prior to weaning.The central and peripheral respiratory pathway is involved in AE-COPD. Central respiratory pathway function is improved after weaning in AE-COPD patients with respiratory failure.
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Affiliation(s)
- Yu Wang
- Department of Neurology, Third Central Hospital of Tianjin
- Tianjin Institute of Hepatobiliary Disease
- Tianjin Key Laboratory of Artificial Cell
- Artificial Cell Engineering Technology Research Center of Public Health Ministry, Tianjin, China
| | - Na Liu
- Department of Neurology, Third Central Hospital of Tianjin
- Tianjin Institute of Hepatobiliary Disease
- Tianjin Key Laboratory of Artificial Cell
- Artificial Cell Engineering Technology Research Center of Public Health Ministry, Tianjin, China
| | - Zhecheng Zhang
- Department of Neurology, Third Central Hospital of Tianjin
- Tianjin Institute of Hepatobiliary Disease
- Tianjin Key Laboratory of Artificial Cell
- Artificial Cell Engineering Technology Research Center of Public Health Ministry, Tianjin, China
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15
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Lenoir C, Jankovski A, Mouraux A. Anodal Transcutaneous Spinal Direct Current Stimulation (tsDCS) Selectively Inhibits the Synaptic Efficacy of Nociceptive Transmission at Spinal Cord Level. Neuroscience 2018; 393:150-163. [PMID: 30321585 DOI: 10.1016/j.neuroscience.2018.10.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Revised: 10/03/2018] [Accepted: 10/05/2018] [Indexed: 12/30/2022]
Abstract
Recently studies have aimed at developing transcutaneous spinal direct current stimulation (tsDCS) as a non-invasive technique to modulate spinal function in humans. Independent studies evaluating its after-effects on nociceptive or non-nociceptive somatosensory responses have reported comparable effects suggesting that tsDCS impairs axonal conduction of both the spino-thalamic and the medial lemniscus tracts. The present study aimed to better understand how tsDCS affects, in humans, the spinal transmission of nociceptive and non-nociceptive somatosensory inputs. We compared the after-effects of anodal low-thoracic, anodal cervical and sham tsDCS on the perception and brain responses elicited by laser stimuli selectively activating Aδ-thermonociceptors of the spinothalamic system and vibrotactile stimuli selectively activating low-threshold Aβ-mechanoreceptors of the lemniscal system, delivered to the hands and feet. Low-thoracic tsDCS selectively and significantly affected the LEP-N2 wave elicited by nociceptive stimulation of the lower limbs, without affecting the LEP-N2 wave elicited by nociceptive stimulation of the upper limbs, and without affecting the SEP-N2 wave elicited by vibrotactile stimulation of either limb. This selective and segmental effect indicates that the neuromodulatory after-effects of tsDCS cannot be explained by anodal blockade of axonal conduction and, instead, are most probably due to a segmental effect on the synaptic efficacy of the local processing and/or transmission of nociceptive inputs in the dorsal horn.
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Affiliation(s)
- Cédric Lenoir
- Institute of Neuroscience (IONS) Université catholique de Louvain (UCL), Brussels, Belgium.
| | - Aleksandar Jankovski
- Institute of Neuroscience (IONS) Université catholique de Louvain (UCL), Brussels, Belgium; Department of Neurosurgery, Université catholique de Louvain (UCL), CHU UCL Namur, Avenue Dr G. Therasse, 5530 Yvoir, Belgium.
| | - André Mouraux
- Institute of Neuroscience (IONS) Université catholique de Louvain (UCL), Brussels, Belgium.
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16
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Does trans-spinal direct current stimulation modulate the Hoffmann reflexes of healthy individuals? A systematic review and meta-analysisc. Spinal Cord 2018; 56:1022-1031. [PMID: 29895879 DOI: 10.1038/s41393-018-0149-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 03/23/2018] [Accepted: 03/29/2018] [Indexed: 12/27/2022]
Abstract
STUDY DESIGN Systematic review and meta-analysis. OBJECTIVES To summarize the available evidence regarding the effects of trans-spinal direct current stimulation (tsDCS) on spinal monosynaptic circuit excitability in healthy individuals. SETTING Applied Neuroscience Laboratory, Brazil. METHODS Abstract screening was performed independently by two authors for studies found in the following databases: PubMed, CINAHL, PsycINFO, Web of Science, and LILACS. If the authors were unable to agree, a third reviewer was consulted. Randomized clinical trials that reported monosynaptic reflex measures were included. Methodological quality was assessed using the Cochrane tool for assessing the risk of bias, and information extracted about the spinal neurophysiological and stimulation protocols and their results. RESULTS The initial search identified 538 studies. After applying the inclusion criteria and excluding duplicates, seven crossover studies were included in the risk of bias assessment, and six studies in the meta-analyses. The meta-analysis results did not show any significant differences between anodal (pooled standardized mean difference (SMD) = -0.09, 95% CI = -0.72 to 0.55, p = 0.79, I2 = 67%) or cathodal tsDCS (pooled SMD = 0.28, 95% CI = -0.07 to 0.63, p = 0.11, I2 = 0%) and sham tsDCS for Hoffmann reflex modulation. CONCLUSION tsDCS did not affect the Hoffmann reflex, as shown in six studies. However, these findings come from studies with selection, performance and detection bias, and further research is needed to examine the effect of this intervention.
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17
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Albuquerque PL, Campêlo M, Mendonça T, Fontes LAM, Brito RDM, Monte-Silva K. Effects of repetitive transcranial magnetic stimulation and trans-spinal direct current stimulation associated with treadmill exercise in spinal cord and cortical excitability of healthy subjects: A triple-blind, randomized and sham-controlled study. PLoS One 2018; 13:e0195276. [PMID: 29596524 PMCID: PMC5875883 DOI: 10.1371/journal.pone.0195276] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 03/18/2018] [Indexed: 11/18/2022] Open
Abstract
Repetitive transcranial magnetic stimulation (rTMS) over motor cortex and trans-spinal direct current stimulation (tsDCS) modulate corticospinal circuits in healthy and injured subjects. However, their associated effects with physical exercise is still not defined. This study aimed to investigate the effect of three different settings of rTMS and tsDCS combined with treadmill exercise on spinal cord and cortical excitability of healthy subjects. We performed a triple blind, randomized, sham-controlled crossover study with 12 healthy volunteers who underwent single sessions of rTMS (1Hz, 20Hz and Sham) and tsDCS (anodal, cathodal and Sham) associated with 20 minutes of treadmill walking. Cortical excitability was assessed by motor evoked potential (MEP) and spinal cord excitability by the Hoffmann reflex (Hr), nociceptive flexion reflex (NFR) and homosynaptic depression (HD). All measures were assessed before, immediately, 30 and 60 minutes after the experimental procedures. Our results demonstrated that anodal tsDCS/treadmill exercise reduced MEP's amplitude and NFR's area compared to sham condition, conversely, cathodal tsDCS/treadmill exercise increased NFR's area. High-frequency rTMS increased MEP's amplitude and NFR's area compared to sham condition. Anodal tsDCS/treadmill exercise and 20Hz rTMS/treadmill exercise reduced Hr amplitude up to 30 minutes after stimulation offset and no changes were observed in HD measures. We demonstrated that tsDCS and rTMS combined with treadmill exercise modulated cortical and spinal cord excitability through different mechanisms. tsDCS modulated spinal reflexes in a polarity-dependent way acting at local spinal circuits while rTMS probably promoted changes in the presynaptic inhibition of spinal motoneurons. In addition, the association of two neuromodulatory techniques induced long-lasting changes.
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Affiliation(s)
- Plínio Luna Albuquerque
- Applied Neuroscience Laboratory, Department of Physical Therapy, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
- Department of Physical Therapy, Centro Universitário Tabosa de Almeida, Caruaru, Pernambuco, Brazil
- Postgraduate Program in Neuropsychiatry and Behavioral Sciences, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
| | - Mayara Campêlo
- Applied Neuroscience Laboratory, Department of Physical Therapy, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
- Postgraduate Program in Neuropsychiatry and Behavioral Sciences, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
| | - Thyciane Mendonça
- Applied Neuroscience Laboratory, Department of Physical Therapy, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
| | - Luís Augusto Mendes Fontes
- Applied Neuroscience Laboratory, Department of Physical Therapy, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
| | - Rodrigo de Mattos Brito
- Applied Neuroscience Laboratory, Department of Physical Therapy, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
| | - Katia Monte-Silva
- Applied Neuroscience Laboratory, Department of Physical Therapy, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
- Postgraduate Program in Neuropsychiatry and Behavioral Sciences, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
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18
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Transspinal Direct Current Stimulation Produces Persistent Plasticity in Human Motor Pathways. Sci Rep 2018; 8:717. [PMID: 29335430 PMCID: PMC5768745 DOI: 10.1038/s41598-017-18872-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 12/19/2017] [Indexed: 11/25/2022] Open
Abstract
The spinal cord is an integration center for descending, ascending, and segmental neural signals. Noninvasive transspinal stimulation may thus constitute an effective method for concomitant modulation of local and distal neural circuits. In this study, we established changes in cortical excitability and input/output function of corticospinal and spinal neural circuits before, at 0–15 and at 30–45 minutes after cathodal, anodal, and sham transspinal direct current stimulation (tsDCS) to the thoracic region in healthy individuals. We found that intracortical inhibition was different among stimulation polarities, however remained unchanged over time. Intracortical facilitation increased after cathodal and anodal tsDCS delivered with subjects seated, and decreased after cathodal tsDCS delivered with subjects lying supine. Both cathodal and anodal tsDCS increased corticospinal excitability, yet facilitation was larger and persisted for 30 minutes post stimulation only when cathodal tsDCS was delivered with subjects lying supine. Spinal input/output reflex function was decreased by cathodal and not anodal tsDCS. These changes may be attributed to altered spontaneous neural activity and membrane potentials of corticomotoneuronal cells by tsDCS involving similar mechanisms to those mediating motor learning. Our findings indicate that thoracic tsDCS has the ability to concomitantly alter cortical, corticospinal, and spinal motor output in humans.
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19
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Dongés SC, Bai S, Taylor JL. Concurrent electrical cervicomedullary stimulation and cervical transcutaneous spinal direct current stimulation result in a stimulus interaction. Exp Physiol 2017; 102:1309-1320. [PMID: 28730695 DOI: 10.1113/ep086360] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 07/03/2017] [Indexed: 01/19/2023]
Abstract
NEW FINDINGS What is the central question of this study? We previously showed that the motor pathway is not modified after cervical transcutaneous spinal direct current stimulation (tsDCS) applied using anterior-posterior electrodes. Here, we examine the motor pathway during stimulation. What is the main finding and its importance? We show that electrically elicited muscle responses to cervicomedullary stimulation are modified during tsDCS, whereas magnetically elicited responses are not. Modelling reveals electrical field modifications during concurrent tsDCS and electrical cervicomedullary stimulation. Changes in muscle response probably result from electrical field modifications rather than physiological changes. Care should be taken when applying electrical stimuli simultaneously. Transcutaneous spinal direct current stimulation (tsDCS) can modulate neuronal excitability within the human spinal cord; however, few studies have used tsDCS at a cervical level. This study aimed to characterize cervical tsDCS further by observing its acute effects on motor responses to transcranial magnetic stimulation and cervicomedullary stimulation. In both studies 1 and 2, participants (study 1, n = 8, four female; and study 2, n = 8, three female) received two periods of 10 min, 3 mA cervical tsDCS on the same day through electrodes placed in an anterior-posterior configuration over the neck; one period with the cathode posterior (c-tsDCS) and the other with the anode posterior (a-tsDCS). In study 1, electrically elicited cervicomedullary motor evoked potentials (eCMEPs) and transcranial magnetic stimulation-elicited motor evoked potentials (MEPs) were measured in biceps brachii and flexor carpi radialis before, during and after each tsDCS period. In study 2, eCMEPs and magnetically elicited CMEPs (mCMEPs) were measured before, during and after each tsDCS period. For study 3, computational modelling was used to observe possible interactions of cervical tsDCS and electrical cervicomedullary stimulation. Studies 1 and 2 revealed that eCMEPs were larger during c-tsDCS and smaller during a-tsDCS compared with those elicited when tsDCS was off (P < 0.05), with no changes in MEPs or mCMEPs. Modelling revealed that eCMEP changes might result from modifications of the electrical field direction and magnitude when combined with cervical tsDCS. Bidirectional eCMEP changes are likely to be caused by an interaction between cervical tsDCS and electrical cervicomedullary stimulation; therefore, care should be taken when combining such electrical stimuli in close proximity.
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Affiliation(s)
- Siobhan C Dongés
- Neuroscience Research Australia, Barker Street, Randwick, NSW, 2031, Australia.,University of New South Wales, Sydney, NSW, 2052, Australia
| | - Siwei Bai
- University of New South Wales, Sydney, NSW, 2052, Australia.,Faculty of Electrical and Computer Engineering, Technical University of Munich, Garching, Germany
| | - Janet L Taylor
- Neuroscience Research Australia, Barker Street, Randwick, NSW, 2031, Australia.,University of New South Wales, Sydney, NSW, 2052, Australia.,Edith Cowan University, Joondalup, WA, 6027, Australia
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