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Tharu NS, Wong AYL, Zheng YP. Transcutaneous Electrical Spinal Cord Stimulation Increased Target-Specific Muscle Strength and Locomotion in Chronic Spinal Cord Injury. Brain Sci 2024; 14:640. [PMID: 39061380 PMCID: PMC11274661 DOI: 10.3390/brainsci14070640] [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: 06/10/2024] [Revised: 06/20/2024] [Accepted: 06/24/2024] [Indexed: 07/28/2024] Open
Abstract
BACKGROUND The recovery of locomotion is greatly prioritized, and neuromodulation has been emerging as a promising approach in recent times. STUDY DESIGN Single-subject research design. SETTINGS A laboratory at The Hong Kong Polytechnic University. OBJECTIVES To investigate the effects of augmenting activity-based therapy (ABT) to transcutaneous electrical spinal cord stimulation (TSCS) on enhancing specific lower limb muscle strength and improving locomotor ability in an individual with chronic incomplete spinal cord injury (iSCI). METHODS An individual with iSCI underwent two phases of treatment, ABT alone followed by combined ABT+TSCS, each for a period of 10 weeks. The TSCS stimulated T10-T11 and T12-L1 segments with a frequency of 30 Hz at an intensity between 105 mA and 130 mA. Manual muscle testing, 6 min walk test (6MWT), and surface electromyography (EMG) responses of specific lower limb muscles were measured. Additionally, spasticity and sensorimotor examinations were conducted every two weeks, while pain tolerance was recorded after each treatment session. RESULTS After the ABT+TSCS treatment, there was an increase in overall muscle strength grading (from 1.8 ± 0.3 to 2.2 ± 0.6 out of 5.0). The 6MWT showed a greater increase in walking distance (3.5 m to 10 m) after combined treatment than ABT alone. In addition, the EMG response of the anterior rectus femoris, biceps femoris, medial gastrocnemius, and tibialis anterior after ABT+TSCS increased more than after ABT alone. The spasticity grade was reduced (from 0.8 ± 0.7 to 0.5 ± 0.6) whereas the average lower limb motor score increased from 17 to 23 points. No adverse effects were reported. CONCLUSIONS ABT+TSCS increased the target-specific lower limb muscle strength and walking ability more than ABT alone in an individual with chronic iSCI.
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Affiliation(s)
- Niraj Singh Tharu
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong SAR, China;
| | - Arnold Yu Lok Wong
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong SAR, China;
- Research Institute for Smart Ageing, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - Yong-Ping Zheng
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong SAR, China;
- Research Institute for Smart Ageing, The Hong Kong Polytechnic University, Hong Kong SAR, China
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Gordineer EA, Stokic DS, Krenn MJ. Distinguishing reflex from non-reflex responses elicited by transcutaneous spinal stimulation targeting the lumbosacral cord in healthy individuals. Exp Brain Res 2024:10.1007/s00221-024-06790-2. [PMID: 38416179 DOI: 10.1007/s00221-024-06790-2] [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: 12/02/2023] [Accepted: 01/21/2024] [Indexed: 02/29/2024]
Abstract
Transcutaneous spinal stimulation (TSS) studies rely on the depolarization of afferent fibers to provide input to the spinal cord; however, this has not been routinely ascertained. Thus, we aimed to characterize the types of responses evoked by TSS and establish paired-pulse ratio cutoffs that distinguish posterior root reflexes, evoked by stimulation of afferent nerve fibers, from motor responses, evoked by stimulation of efferent nerve fibers. Twelve neurologically intact participants (six women) underwent unipolar TSS (cathode over T11-12 spinal processes, anode paraumbilically) while resting supine. In six participants, unipolar TSS was repeated 2-3 months later and also compared to a bipolar TSS configuration (cathode 2.5 cm below T11-12, anode 5 cm above cathode). EMG signals were recorded from 16 leg muscles. A paired-pulse paradigm was applied at interstimulus intervals (ISIs) of 25, 50, 100, 200, and 400 ms. Responses were categorized by three assessors into reflexes, motor responses, or their combination (mixed responses) based on the visual presence/absence of paired-pulse suppression across ISIs. The paired-pulse ratio that best discriminated between response types was derived for each ISI. These cutoffs were validated by repeating unipolar TSS 2-3 months later and with bipolar TSS. Unipolar TSS evoked only reflexes (90%) and mixed responses (10%), which were mainly recorded in the quadriceps muscles (25-42%). Paired-pulse ratios of 0.51 (25-ms ISI) and 0.47 (50-ms ISI) best distinguished reflexes from mixed responses (100% sensitivity, > 99.2% specificity). These cutoffs performed well in the repeated unipolar TSS session (100% sensitivity, > 89% specificity). Bipolar TSS exclusively elicited reflexes which were all correctly classified. These results can be utilized in future studies to ensure that the input to the spinal cord originates from the depolarization of large afferents. This knowledge can be applied to improve the design of future neurophysiological studies and increase the fidelity of neuromodulation interventions.
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Affiliation(s)
- Elizabeth A Gordineer
- School of Graduate Studies in the Health Sciences, Program in Neuroscience, University of Mississippi Medical Center, Jackson, MS, USA
- Center for Neuroscience and Neurological Recovery, Methodist Rehabilitation Center, Jackson, MS, USA
| | - Dobrivoje S Stokic
- Center for Neuroscience and Neurological Recovery, Methodist Rehabilitation Center, Jackson, MS, USA
| | - Matthias J Krenn
- Center for Neuroscience and Neurological Recovery, Methodist Rehabilitation Center, Jackson, MS, USA.
- Department of Neurosurgery, University of Mississippi Medical Center, 2500 N State St, Jackson, MS, 39216, USA.
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Bryson N, Lombardi L, Hawthorn R, Fei J, Keesey R, Peiffer J, Seáñez I. Enhanced selectivity of transcutaneous spinal cord stimulation by multielectrode configuration. J Neural Eng 2023; 20:10.1088/1741-2552/ace552. [PMID: 37419109 PMCID: PMC10481387 DOI: 10.1088/1741-2552/ace552] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 07/07/2023] [Indexed: 07/09/2023]
Abstract
Objective.Transcutaneous spinal cord stimulation (tSCS) has been gaining momentum as a non-invasive rehabilitation approach to restore movement to paralyzed muscles after spinal cord injury (SCI). However, its low selectivity limits the types of movements that can be enabled and, thus, its potential applications in rehabilitation.Approach.In this cross-over study design, we investigated whether muscle recruitment selectivity of individual muscles could be enhanced by multielectrode configurations of tSCS in 16 neurologically intact individuals. We hypothesized that due to the segmental innervation of lower limb muscles, we could identify muscle-specific optimal stimulation locations that would enable improved recruitment selectivity over conventional tSCS. We elicited leg muscle responses by delivering biphasic pulses of electrical stimulation to the lumbosacral enlargement using conventional and multielectrode tSCS.Results.Analysis of recruitment curve responses confirmed that multielectrode configurations could improve the rostrocaudal and lateral selectivity of tSCS. To investigate whether motor responses elicited by spatially selective tSCS were mediated by posterior root-muscle reflexes, each stimulation event was a paired pulse with a conditioning-test interval of 33.3 ms. Muscle responses to the second stimulation pulse were significantly suppressed, a characteristic of post-activation depression suggesting that spatially selective tSCS recruits proprioceptive fibers that reflexively activate muscle-specific motor neurons in the spinal cord. Moreover, the combination of leg muscle recruitment probability and segmental innervation maps revealed a stereotypical spinal activation map in congruence with each electrode's position.Significance. Improvements in muscle recruitment selectivity could be essential for the effective translation into stimulation protocols that selectively enhance single-joint movements in neurorehabilitation.
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Affiliation(s)
- Noah Bryson
- Biomedical Engineering, Washington University in St. Louis
- Division of Neurotechnology, Washington University School of Medicine in St. Louis
| | - Lorenzo Lombardi
- Biomedical Engineering, Washington University in St. Louis
- Division of Neurotechnology, Washington University School of Medicine in St. Louis
| | - Rachel Hawthorn
- Biomedical Engineering, Washington University in St. Louis
- Division of Neurotechnology, Washington University School of Medicine in St. Louis
| | - Jie Fei
- Biomedical Engineering, Washington University in St. Louis
- Division of Neurotechnology, Washington University School of Medicine in St. Louis
| | - Rodolfo Keesey
- Biomedical Engineering, Washington University in St. Louis
- Division of Neurotechnology, Washington University School of Medicine in St. Louis
| | - J.D. Peiffer
- Biomedical Engineering, Washington University in St. Louis
- Division of Neurotechnology, Washington University School of Medicine in St. Louis
- Biomedical Engineering, Northwestern University
| | - Ismael Seáñez
- Biomedical Engineering, Washington University in St. Louis
- Division of Neurotechnology, Washington University School of Medicine in St. Louis
- Neurosurgery, Washington University School of Medicine in St. Louis
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Finn HT, Bye EA, Elphick TG, Boswell-Ruys CL, Gandevia SC, Butler JE, Héroux ME. Transcutaneous spinal stimulation in people with and without spinal cord injury: Effect of electrode placement and trains of stimulation on threshold intensity. Physiol Rep 2023; 11:e15692. [PMID: 37269156 PMCID: PMC10238786 DOI: 10.14814/phy2.15692] [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: 04/21/2023] [Accepted: 05/03/2023] [Indexed: 06/04/2023] Open
Abstract
Transcutaneous spinal cord stimulation (TSS) is purported to improve motor function in people after spinal cord injury (SCI). However, several methodology aspects are yet to be explored. We investigated whether stimulation configuration affected the intensity needed to elicit spinally evoked motor responses (sEMR) in four lower limb muscles bilaterally. Also, since stimulation intensity for therapeutic TSS (i.e., trains of stimulation, typically delivered at 15-50 Hz) is sometimes based on the single-pulse threshold intensity, we compared these two stimulation types. In non-SCI participants (n = 9) and participants with a SCI (n = 9), three different electrode configurations (cathode-anode); L1-midline (below the umbilicus), T11-midline and L1-ASIS (anterior superior iliac spine; non-SCI only) were compared for the sEMR threshold intensity using single pulses or trains of stimulation which were recorded in the vastus medialis, medial hamstring, tibialis anterior, medial gastrocnemius muscles. In non-SCI participants, the L1-midline configuration showed lower sEMR thresholds compared to T11-midline (p = 0.002) and L1-ASIS (p < 0.001). There was no difference between T11-midline and L1-midline for participants with SCI (p = 0.245). Spinally evoked motor response thresholds were ~13% lower during trains of stimulation compared to single pulses in non-SCI participants (p < 0.001), but not in participants with SCI (p = 0.101). With trains of stimulation, threshold intensities were slightly lower and the incidence of sEMR was considerably lower. Overall, stimulation threshold intensities were generally lower with the L1-midline electrode configuration and is therefore preferred. While single-pulse threshold intensities may overestimate threshold intensities for therapeutic TSS, tolerance to trains of stimulation will be the limiting factor in most cases.
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Affiliation(s)
- Harrison T Finn
- Neuroscience Research Australia, Randwick, New South Wales, Australia
- School of Biomedical Sciences, University of New South Wales, New South Wales, Kensington, Australia
| | - Elizabeth A Bye
- Neuroscience Research Australia, Randwick, New South Wales, Australia
- School of Biomedical Sciences, University of New South Wales, New South Wales, Kensington, Australia
- Prince of Wales Hospital, Randwick, New South Wales, Australia
| | - Thomas G Elphick
- Neuroscience Research Australia, Randwick, New South Wales, Australia
- School of Biomedical Sciences, University of New South Wales, New South Wales, Kensington, Australia
| | - Claire L Boswell-Ruys
- Neuroscience Research Australia, Randwick, New South Wales, Australia
- School of Biomedical Sciences, University of New South Wales, New South Wales, Kensington, Australia
- Prince of Wales Hospital, Randwick, New South Wales, Australia
| | - Simon C Gandevia
- Neuroscience Research Australia, Randwick, New South Wales, Australia
- Prince of Wales Hospital, Randwick, New South Wales, Australia
- School of Clinical Medicine, University of New South Wales, New South Wales, Kensington, Australia
| | - Jane E Butler
- Neuroscience Research Australia, Randwick, New South Wales, Australia
- School of Biomedical Sciences, University of New South Wales, New South Wales, Kensington, Australia
| | - Martin E Héroux
- Neuroscience Research Australia, Randwick, New South Wales, Australia
- School of Biomedical Sciences, University of New South Wales, New South Wales, Kensington, Australia
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Grover FM, Chen B, Perez MA. Increased paired stimuli enhance corticospinal-motoneuronal plasticity in humans with spinal cord injury. J Neurophysiol 2023; 129:1414-1422. [PMID: 36752493 PMCID: PMC10259851 DOI: 10.1152/jn.00499.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/19/2023] [Accepted: 01/19/2023] [Indexed: 02/09/2023] Open
Abstract
Paired corticospinal-motoneuronal stimulation (PCMS) has been used to enhance corticospinal excitability and functional outcomes in humans with spinal cord injury (SCI). Here, we examined the effect of increasing the number of paired pulses on PCMS-induced plasticity. During PCMS, corticospinal volleys evoked by transcranial magnetic stimulation (TMS) over the hand motor cortex were timed to arrive at corticospinal-motoneuronal synapses of the first dorsal interosseous (FDI) muscle 1-2 ms before the arrival of antidromic potentials elicited in motoneurons by electrical stimulation of the ulnar nerve. We tested motor-evoked potentials (MEPs) elicited by TMS over the hand motor cortex and electrical stimulation at the cervicomedullary junction (CMEPs) in the FDI muscle before and after 180 paired pulses (PCMS-180) followed up by another 180 paired pulses (PCMS-360) in humans with and without chronic incomplete cervical SCI. The nine-hole-peg-test (9HPT) was measured before and after PCMS paired pulses in individuals with SCI. We found that the size of MEPs and CMEPs increased after PCMS-180 in both groups compared with baseline and further increased after PCMS-360 in participants with SCI, suggesting a spinal origin for these effects. Notably, in people with SCI, the time to complete the 9HPT decreased after PCMS-180 and further decreased after PCMS-360 compared with baseline but not when the 9HPT was repeated overtime. Our findings demonstrate that increasing the number of PCMS paired pulses potentiates corticospinal excitability and voluntary motor output after SCI, likely through spinal plasticity. This proof-of-principle study suggests that increasing the PCMS dose represents a strategy to boost voluntary motor output after SCI.NEW & NOTEWORTHY Paired corticospinal-motoneuronal stimulation (PCMS) has been used to enhance corticospinal excitability and functional outcomes in humans with spinal cord injury (SCI). Here, we demonstrate that 360 paired pulses resulted in larger increases in motor-evoked potential size in a hand muscle and in a better ability to complete the nine-hold-peg-test compared with 180 paired pulses in people with SCI. This proof-of-principle study suggests that increasing the PCMS dose represents a strategy to boost motor output after SCI.
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Affiliation(s)
- Francis M Grover
- Shirley Ryan AbilityLab, Chicago, Illinois, United States
- Department of Physical Therapy and Human Movement Sciences, Northwestern University, Chicago, Illinois, United States
| | - Bing Chen
- Shirley Ryan AbilityLab, Chicago, Illinois, United States
- Edward Hines Jr. VA Hospital, Chicago, Illinois, United States
| | - Monica A Perez
- Shirley Ryan AbilityLab, Chicago, Illinois, United States
- Department of Physical Therapy and Human Movement Sciences, Northwestern University, Chicago, Illinois, United States
- Department of Physical Medicine and Rehabilitation, Northwestern University, Chicago, Illinois, United States
- Edward Hines Jr. VA Hospital, Chicago, Illinois, United States
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Bryson N, Lombardi L, Hawthorn R, Fei J, Keesey R, Peiffer JD, Seáñez I. Enhanced selectivity of transcutaneous spinal cord stimulation by multielectrode configuration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.30.534835. [PMID: 37034788 PMCID: PMC10081184 DOI: 10.1101/2023.03.30.534835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Objective Transcutaneous spinal cord stimulation (tSCS) has been gaining momentum as a non-invasive rehabilitation approach to restore movement to paralyzed muscles after spinal cord injury (SCI). However, its low selectivity limits the types of movements that can be enabled and, thus, its potential applications in rehabilitation. Approach In this cross-over study design, we investigated whether muscle recruitment selectivity of individual muscles could be enhanced by multielectrode configurations of tSCS in 16 neurologically intact individuals. We hypothesized that due to the segmental innervation of lower limb muscles, we could identify muscle-specific optimal stimulation locations that would enable improved recruitment selectivity over conventional tSCS. We elicited leg muscle responses by delivering biphasic pulses of electrical stimulation to the lumbosacral enlargement using conventional and multielectrode tSCS. Results Analysis of recruitment curve responses confirmed that multielectrode configurations could improve the rostrocaudal and lateral selectivity of tSCS. To investigate whether motor responses elicited by spatially selective tSCS were mediated by posterior root-muscle reflexes, each stimulation event was a paired pulse with a conditioning-test interval of 33.3 ms. Muscle responses to the second stimulation pulse were significantly suppressed, a characteristic of post-activation depression suggesting that spatially selective tSCS recruits proprioceptive fibers that reflexively activate muscle-specific motor neurons in the spinal cord. Moreover, the combination of leg muscle recruitment probability and segmental innervation maps revealed a stereotypical spinal activation map in congruence with each electrode's position. Significance Improvements in muscle recruitment selectivity could be essential for the effective translation into stimulation protocols that selectively enhance single-joint movements in neurorehabilitation.
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García-Alén L, Kumru H, Castillo-Escario Y, Benito-Penalva J, Medina-Casanovas J, Gerasimenko YP, Edgerton VR, García-Alías G, Vidal J. Transcutaneous Cervical Spinal Cord Stimulation Combined with Robotic Exoskeleton Rehabilitation for the Upper Limbs in Subjects with Cervical SCI: Clinical Trial. Biomedicines 2023; 11:biomedicines11020589. [PMID: 36831125 PMCID: PMC9953486 DOI: 10.3390/biomedicines11020589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Revised: 02/06/2023] [Accepted: 02/13/2023] [Indexed: 02/18/2023] Open
Abstract
(1) Background: Restoring arm and hand function is a priority for individuals with cervical spinal cord injury (cSCI) for independence and quality of life. Transcutaneous spinal cord stimulation (tSCS) promotes the upper extremity (UE) motor function when applied at the cervical region. The aim of the study was to determine the effects of cervical tSCS, combined with an exoskeleton, on motor strength and functionality of UE in subjects with cSCI. (2) Methods: twenty-two subjects participated in the randomized mix of parallel-group and crossover clinical trial, consisting of an intervention group (n = 15; tSCS exoskeleton) and a control group (n = 14; exoskeleton). The assessment was carried out at baseline, after the last session, and two weeks after the last session. We assessed graded redefined assessment of strength, sensibility, and prehension (GRASSP), box and block test (BBT), spinal cord independence measure III (SCIM-III), maximal voluntary contraction (MVC), ASIA impairment scale (AIS), and WhoQol-Bref; (3) Results: GRASSP, BBT, SCIM III, cylindrical grip force and AIS motor score showed significant improvement in both groups (p ≤ 0.05), however, it was significantly higher in the intervention group than the control group for GRASSP strength, and GRASSP prehension ability (p ≤ 0.05); (4) Conclusion: our findings show potential advantages of the combination of cervical tSCS with an exoskeleton to optimize the outcome for UE.
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Affiliation(s)
- Loreto García-Alén
- Fundación Institut Guttmann, Institut Universitari de Neurorrehabilitació Adscrit a la UAB, 08916 Badalona, Spain
- Universitat Autónoma de Barcelona, 08193 Barcelona, Spain
| | - Hatice Kumru
- Fundación Institut Guttmann, Institut Universitari de Neurorrehabilitació Adscrit a la UAB, 08916 Badalona, Spain
- Universitat Autónoma de Barcelona, 08193 Barcelona, Spain
- Fundació Institut d’Investigació en Ciéncies de la Salut Germans Trias i Pujol, 08916 Badalona, Spain
- Correspondence:
| | - Yolanda Castillo-Escario
- Institute for Bioengineering of Catalonia, Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
- Department of Automatic Control, Universitat Politécnica de Catalunya-Barcelona Tech (UPC), 08028 Barcelona, Spain
- Centro de Investigación Biomédica en Red de Bioingeniería, Biomateriales y Nanomedicina, 28029 Madrid, Spain
| | - Jesús Benito-Penalva
- Fundación Institut Guttmann, Institut Universitari de Neurorrehabilitació Adscrit a la UAB, 08916 Badalona, Spain
- Universitat Autónoma de Barcelona, 08193 Barcelona, Spain
- Fundació Institut d’Investigació en Ciéncies de la Salut Germans Trias i Pujol, 08916 Badalona, Spain
| | - Josep Medina-Casanovas
- Fundación Institut Guttmann, Institut Universitari de Neurorrehabilitació Adscrit a la UAB, 08916 Badalona, Spain
- Universitat Autónoma de Barcelona, 08193 Barcelona, Spain
- Fundació Institut d’Investigació en Ciéncies de la Salut Germans Trias i Pujol, 08916 Badalona, Spain
| | - Yury P. Gerasimenko
- Pavlov Institute of Physiology, St. Petersburg 199034, Russia
- Department of Physiology and Biophysics, University of Louisville, Louisville, KY 40292, USA
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY 40292, USA
| | - Victor Reggie Edgerton
- Rancho Research Institute, Los Amigos National Rehabilitation Center, Downey, CA 90242, USA
| | - Guillermo García-Alías
- Fundación Institut Guttmann, Institut Universitari de Neurorrehabilitació Adscrit a la UAB, 08916 Badalona, Spain
- Departament de Biologia Cel·lular, Fisiologia i Immunologia & Insititute of Neuroscience, Universitat Autónoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
| | - Joan Vidal
- Fundación Institut Guttmann, Institut Universitari de Neurorrehabilitació Adscrit a la UAB, 08916 Badalona, Spain
- Universitat Autónoma de Barcelona, 08193 Barcelona, Spain
- Fundació Institut d’Investigació en Ciéncies de la Salut Germans Trias i Pujol, 08916 Badalona, Spain
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Neuromodulation with transcutaneous spinal stimulation reveals different groups of motor profiles during robot-guided stepping in humans with incomplete spinal cord injury. Exp Brain Res 2023; 241:365-382. [PMID: 36534141 PMCID: PMC10278039 DOI: 10.1007/s00221-022-06521-5] [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: 08/16/2022] [Accepted: 12/03/2022] [Indexed: 12/23/2022]
Abstract
Neuromodulation via spinal stimulation has been investigated for improving motor function and reducing spasticity after spinal cord injury (SCI) in humans. Despite the reported heterogeneity of outcomes, few investigations have attempted to discern commonalities among individual responses to neuromodulation, especially the impact of stimulation frequencies. Here, we examined how exposure to continuous lumbosacral transcutaneous spinal stimulation (TSS) across a range of frequencies affects robotic torques and EMG patterns during stepping in a robotic gait orthosis on a motorized treadmill. We studied nine chronic motor-incomplete SCI individuals (8/1 AIS-C/D, 8 men) during robot-guided stepping with body-weight support without and with TSS applied at random frequencies between 1 and up to 100 Hz at a constant, individually selected stimulation intensity below the common motor threshold for posterior root reflexes. The hip and knee robotic torques needed to maintain the predefined stepping trajectory and EMG in eight bilateral leg muscles were recorded. We calculated the standardized mean difference between the stimulation conditions grouped into frequency bins and the no stimulation condition to determine changes in the normalized torques and the average EMG envelopes. We found heterogeneous changes in robotic torques across individuals. Agglomerative clustering of robotic torques identified four groups wherein the patterns of changes differed in magnitude and direction depending mainly on the stimulation frequency and stance/swing phase. On one end of the spectrum, the changes in robotic torques were greater with increasing stimulation frequencies (four participants), which coincided with a decrease in EMG, mainly due to the reduction of clonogenic motor output in the lower leg muscles. On the other end, we found an inverted u-shape change in torque over the mid-frequency range along with an increase in EMG, reflecting the augmentation of gait-related physiological (two participants) or pathophysiological (one participant) output. We conclude that TSS during robot-guided stepping reveals different frequency-dependent motor profiles among individuals with chronic motor incomplete SCI. This suggests the need for a better understanding and characterization of motor control profiles in SCI when applying TSS as a therapeutic intervention for improving gait.
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Rehman MU, Sneed D, Sutor TW, Hoenig H, Gorgey AS. Optimization of Transspinal Stimulation Applications for Motor Recovery after Spinal Cord Injury: Scoping Review. J Clin Med 2023; 12:854. [PMID: 36769503 PMCID: PMC9917510 DOI: 10.3390/jcm12030854] [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: 11/17/2022] [Revised: 01/13/2023] [Accepted: 01/17/2023] [Indexed: 01/25/2023] Open
Abstract
Spinal cord injury (SCI) is a debilitating condition that can significantly affect an individual's life, causing paralysis, autonomic dysreflexia, and chronic pain. Transspinal stimulation (TSS) is a non-invasive form of neuromodulation that activates the underlying neural circuitries of the spinal cord. Application of TSS can be performed through multiple stimulation protocols, which may vary in the electrodes' size or position as well as stimulation parameters, and which may influence the response of motor functions to the stimulation. Due to the novelty of TSS, it is beneficial to summarize the available evidence to identify the range of parameters that may provide the best outcomes for motor response. The PubMed and Google Scholar databases were searched for studies examining the effects of TSS on limb motor function. A literature search yielded 34 studies for analysis, in which electrode placement and stimulation parameters varied considerably. The stimulation protocols from each study and their impact on limb motor function were summarized. Electrode placement was variable based on the targeted limb. Studies for the upper limbs targeted the cervical enlargement with anatomical placement of the cathode over the cervical vertebral region. In lower-limb studies, the cathode(s) were placed over the thoracic and lumbar vertebral regions, to target the lumbar enlargement. The effects of carrier frequency were inconclusive across the studies. Multisite cathodal placements yielded favorable motor response results compared to single-site placement. This review briefly summarized the current mechanistic evidence of the effect of TSS on motor response after SCI. Our findings indicate that optimization of stimulation parameters will require future randomized controlled studies to independently assess the effects of different stimulation parameters under controlled circumstances.
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Affiliation(s)
- Muhammad Uzair Rehman
- Spinal Cord Injury and Disorders, Hunter Holmes McGuire VA Medical Center, Richmond, VA 23249, USA
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Dustin Sneed
- Department of Physical Medicine and Rehabilitation, School of Medicine, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Tommy W. Sutor
- Spinal Cord Injury and Disorders, Hunter Holmes McGuire VA Medical Center, Richmond, VA 23249, USA
| | - Helen Hoenig
- Physical Medicine & Rehabilitation Service, Durham VA Health Care System, Durham, NC 27705, USA
- Geriatrics Division, Department of Medicine, Duke University, Durham, NC 27710, USA
| | - Ashraf S. Gorgey
- Spinal Cord Injury and Disorders, Hunter Holmes McGuire VA Medical Center, Richmond, VA 23249, USA
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA
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Combined Transcutaneous Electrical Spinal Cord Stimulation and Task-Specific Rehabilitation Improves Trunk and Sitting Functions in People with Chronic Tetraplegia. Biomedicines 2022; 11:biomedicines11010034. [PMID: 36672542 PMCID: PMC9855778 DOI: 10.3390/biomedicines11010034] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 12/19/2022] [Accepted: 12/20/2022] [Indexed: 12/28/2022] Open
Abstract
The aim of this study was to examine the effects of transcutaneous electrical spinal cord stimulation (TSCS) and conventional task-specific rehabilitation (TSR) on trunk control and sitting stability in people with chronic tetraplegia secondary to a spinal cord injury (SCI). Five individuals with complete cervical (C4-C7) cord injury participated in 24-week therapy that combined TSCS and TSR in the first 12 weeks, followed by TSR alone for another 12 weeks. The TSCS was delivered simultaneously at T11 and L1 spinal levels, at a frequency ranging from 20-30 Hz with 0.1-1.0 ms. pulse width biphasically. Although the neurological prognosis did not manifest after either treatment, the results show that there were significant increases in forward reach distance (10.3 ± 4.5 cm), right lateral reach distance (3.7 ± 1.8 cm), and left lateral reach distance (3.0 ± 0.9 cm) after the combinational treatment (TSCS+TSR). The stimulation also significantly improved the participants' trunk control and function in sitting. Additionally, the trunk range of motion and the electromyographic response of the trunk muscles were significantly elevated after TSCS+TSR. The TSCS+TSR intervention improved independent trunk control with significantly increased static and dynamic sitting balance, which were maintained throughout the TSR period and the follow-up period, indicating long-term sustainable recovery.
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Lopez J, Forrest GF, Engel-Haber E, Snider B, Momeni K, Ravi M, Kirshblum S. Transcutaneous spinal stimulation in patients with intrathecal baclofen pump delivery system: A preliminary safety study. Front Neurosci 2022; 16:1075293. [PMID: 36620445 PMCID: PMC9811171 DOI: 10.3389/fnins.2022.1075293] [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: 10/20/2022] [Accepted: 12/05/2022] [Indexed: 12/24/2022] Open
Abstract
Objective To determine the effect of transcutaneous spinal stimulation (TSS) on an implanted intrathecal baclofen (ITB) pump in persons with traumatic spinal cord injury (SCI). Design Prospective clinical trial. Participants Five individuals with chronic traumatic SCI, >18 years of age, and an anteriorly implanted Medtronic SynchroMed™ II ITB pump delivery system. Intervention Transcutaneous spinal stimulation trials with cathode at T11/12, with pump interrogation before, during and after stimulation. Results There was no evidence of any effect of the TSS in regards to disruption of the ITB pump delivery mechanism. Communication interference with the interrogator to the pump occurred often during stimulation for log transmission most likely secondary to the electromagnetic interference from the stimulation. One individual had elevated blood pressure at the end of the trial, suspected to be unrelated to the spinal stimulation. Conclusion Based upon this pilot study, further TSS studies including persons with an implanted Medtronic SynchroMed™ II ITB pump can be considered when stimulating at the low thoracic spine, although communication with the programmer during the stimulation may be affected.
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Affiliation(s)
- John Lopez
- Kessler Institute for Rehabilitation, West Orange, NJ, United States,New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, United States,*Correspondence: John Lopez,
| | - Gail F. Forrest
- New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, United States,Kessler Foundation, West Orange, NJ, United States
| | - Einat Engel-Haber
- New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, United States,Kessler Foundation, West Orange, NJ, United States
| | - Brittany Snider
- Kessler Institute for Rehabilitation, West Orange, NJ, United States,New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, United States,Kessler Foundation, West Orange, NJ, United States
| | - Kam Momeni
- Koneksa Health, New York, NY, United States
| | | | - Steven Kirshblum
- Kessler Institute for Rehabilitation, West Orange, NJ, United States,New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, United States,Kessler Foundation, West Orange, NJ, United States
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Hofstoetter US, Minassian K. Transcutaneous Spinal Cord Stimulation: Advances in an Emerging Non-Invasive Strategy for Neuromodulation. J Clin Med 2022; 11:jcm11133836. [PMID: 35807121 PMCID: PMC9267622 DOI: 10.3390/jcm11133836] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 06/30/2022] [Indexed: 12/04/2022] Open
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Transcutaneous spinal cord stimulation combined with locomotor training to improve walking ability in people with chronic spinal cord injury: study protocol for an international multi-centred double-blinded randomised sham-controlled trial (eWALK). Spinal Cord 2022; 60:491-497. [PMID: 35013547 DOI: 10.1038/s41393-021-00734-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 11/23/2021] [Accepted: 11/25/2021] [Indexed: 11/09/2022]
Abstract
STUDY DESIGN An international multi-centred, double-blinded, randomised sham-controlled trial (eWALK). OBJECTIVE To determine the effect of 12 weeks of transcutaneous spinal stimulation (TSS) combined with locomotor training on walking ability in people with spinal cord injury (SCI). SETTING Dedicated SCI research centres in Australia, Spain, USA and Scotland. METHODS Fifty community-dwelling individuals with chronic SCI will be recruited. Participants will be eligible if they have bilateral motor levels between T1 and T11, a reproducible lower limb muscle contraction in at least one muscle group, and a Walking Index for SCI II (WISCI II) between 1 and 6. Eligible participants will be randomised to one of two groups, either the active stimulation group or the sham stimulation group. Participants allocated to the stimulation group will receive TSS combined with locomotor training for three 30-min sessions a week for 12 weeks. The locomotor sessions will include walking on a treadmill and overground. Participants allocated to the sham stimulation group will receive the same locomotor training combined with sham stimulation. The primary outcome will be walking ability with stimulation using the WISCI II. Secondary outcomes will record sensation, strength, spasticity, bowel function and quality of life. TRIAL REGISTRATION ANZCTR.org.au identifier ACTRN12620001241921.
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Rahman MA, Tharu NS, Gustin SM, Zheng YP, Alam M. Trans-Spinal Electrical Stimulation Therapy for Functional Rehabilitation after Spinal Cord Injury: Review. J Clin Med 2022; 11:1550. [PMID: 35329875 PMCID: PMC8954138 DOI: 10.3390/jcm11061550] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/04/2022] [Accepted: 03/09/2022] [Indexed: 01/25/2023] Open
Abstract
Spinal cord injury (SCI) is one of the most debilitating injuries in the world. Complications after SCI, such as respiratory issues, bowel/bladder incontinency, pressure ulcers, autonomic dysreflexia, spasticity, pain, etc., lead to immense suffering, a remarkable reduction in life expectancy, and even premature death. Traditional rehabilitations for people with SCI are often insignificant or ineffective due to the severity and complexity of the injury. However, the recent development of noninvasive electrical neuromodulation treatments to the spinal cord have shed a ray of hope for these individuals to regain some of their lost functions, a reduction in secondary complications, and an improvement in their life quality. For this review, 250 articles were screened and about 150 were included to summarize the two most promising noninvasive spinal cord electrical stimulation methods of SCI rehabilitation treatment, namely, trans-spinal direct current stimulation (tsDCS) and trans-spinal pulsed current stimulation (tsPCS). Both treatments have demonstrated good success in not only improving the sensorimotor function, but also autonomic functions. Due to the noninvasive nature and lower costs of these treatments, in the coming years, we expect these treatments to be integrated into regular rehabilitation therapies worldwide.
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Affiliation(s)
- Md. Akhlasur Rahman
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong, China; (M.A.R.); (N.S.T.); (Y.-P.Z.)
- Centre for the Rehabilitation of the Paralysed (CRP), Savar Union 1343, Bangladesh
| | - Niraj Singh Tharu
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong, China; (M.A.R.); (N.S.T.); (Y.-P.Z.)
| | - Sylvia M. Gustin
- NeuroRecovery Research Hub, School of Psychology, University of New South Wales, Sydney, NSW 2052, Australia;
- Centre for Pain IMPACT, Neuroscience Research Australia, Sydney, NSW 2031, Australia
| | - Yong-Ping Zheng
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong, China; (M.A.R.); (N.S.T.); (Y.-P.Z.)
| | - Monzurul Alam
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong, China; (M.A.R.); (N.S.T.); (Y.-P.Z.)
- NeuroRecovery Research Hub, School of Psychology, University of New South Wales, Sydney, NSW 2052, Australia;
- Centre for Pain IMPACT, Neuroscience Research Australia, Sydney, NSW 2031, Australia
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15
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Balbinot G, Joner Wiest M, Li G, Pakosh M, Cesar Furlan J, Kalsi-Ryan S, Zariffa J. The use of surface EMG in neurorehabilitation following traumatic spinal cord injury: a scoping review. Clin Neurophysiol 2022; 138:61-73. [DOI: 10.1016/j.clinph.2022.02.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 02/06/2022] [Accepted: 02/27/2022] [Indexed: 11/03/2022]
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Influence of Spine Curvature on the Efficacy of Transcutaneous Lumbar Spinal Cord Stimulation. J Clin Med 2021; 10:jcm10235543. [PMID: 34884249 PMCID: PMC8658162 DOI: 10.3390/jcm10235543] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 11/15/2021] [Accepted: 11/24/2021] [Indexed: 12/15/2022] Open
Abstract
Transcutaneous spinal cord stimulation is a non-invasive method for neuromodulation of sensorimotor function. Its main mechanism of action results from the activation of afferent fibers in the posterior roots-the same structures as targeted by epidural stimulation. Here, we investigated the influence of sagittal spine alignment on the capacity of the surface-electrode-based stimulation to activate these neural structures. We evaluated electromyographic responses evoked in the lower limbs of ten healthy individuals during extension, flexion, and neutral alignment of the thoracolumbar spine. To control for position-specific effects, stimulation in these spine alignment conditions was performed in four different body positions. In comparison to neutral and extended spine alignment, flexion of the spine resulted in a strong reduction of the response amplitudes. There was no such effect on tibial-nerve evoked H reflexes. Further, there was a reduction of post-activation depression of the responses to transcutaneous spinal cord stimulation evoked in spinal flexion. Thus, afferent fibers were reliably activated with neutral and extended spine alignment. Spinal flexion, however, reduced the capacity of the stimulation to activate afferent fibers and led to the co-activation of motor fibers in the anterior roots. This change of action was due to biophysical rather than neurophysiological influences. We recommend applying transcutaneous spinal cord stimulation in body positions that allow individuals to maintain a neutral or extended spine.
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Taylor C, McHugh C, Mockler D, Minogue C, Reilly RB, Fleming N. Transcutaneous spinal cord stimulation and motor responses in individuals with spinal cord injury: A methodological review. PLoS One 2021; 16:e0260166. [PMID: 34793572 PMCID: PMC8601579 DOI: 10.1371/journal.pone.0260166] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 11/03/2021] [Indexed: 11/18/2022] Open
Abstract
Background Transcutaneous spinal cord stimulation (tSCS) is a non-invasive modality in which electrodes can stimulate spinal circuitries and facilitate a motor response. This review aimed to evaluate the methodology of studies using tSCS to generate motor activity in persons with spinal cord injury (SCI) and to appraise the quality of included trials. Methods A systematic search for studies published until May 2021 was made of the following databases: EMBASE, Medline (Ovid) and Web of Science. Two reviewers independently screened the studies, extracted the data, and evaluated the quality of included trials. The electrical characteristics of stimulation were summarised to allow for comparison across studies. In addition, the surface electromyography (EMG) recording methods were evaluated. Results A total of 3753 articles were initially screened, of which 25 met the criteria for inclusion. Studies were divided into those using tSCS for neurophysiological investigations of reflex responses (n = 9) and therapeutic investigations of motor recovery (n = 16). The overall quality of evidence was deemed to be poor-to-fair (10.5 ± 4.9) based on the Downs and Black Quality Checklist criteria. The electrical characteristics were collated to establish the dosage range across stimulation trials. The methods employed by included studies relating to stimulation parameters and outcome measurement varied extensively, although some trends are beginning to appear in relation to electrode configuration and EMG outcomes. Conclusion This review outlines the parameters currently employed for tSCS of the cervicothoracic and thoracolumbar regions to produce motor responses. However, to establish standardised procedures for neurophysiological assessments and therapeutic investigations of tSCS, further high-quality investigations are required, ideally utilizing consistent electrophysiological recording methods, and reporting common characteristics of the electrical stimulation administered.
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Affiliation(s)
- Clare Taylor
- Department of Anatomy, School of Medicine, Trinity College, The University of Dublin, Dublin, Ireland
- * E-mail:
| | - Conor McHugh
- Department of Anatomy, School of Medicine, Trinity College, The University of Dublin, Dublin, Ireland
| | - David Mockler
- John Stearne Medical Library, Trinity Centre for Health Sciences, School of Medicine, St. James’s Hospital, Dublin, Ireland
| | - Conor Minogue
- Department of Anatomy, School of Medicine, Trinity College, The University of Dublin, Dublin, Ireland
| | - Richard B. Reilly
- Trinity Centre for Biomedical Engineering, Trinity College, The University of Dublin, Dublin, Ireland
- School of Engineering, Trinity College, The University of Dublin, Dublin, Ireland
- School of Medicine, Trinity College, The University of Dublin, Dublin, Ireland
| | - Neil Fleming
- Department of Anatomy, School of Medicine, Trinity College, The University of Dublin, Dublin, Ireland
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Al'joboori Y, Hannah R, Lenham F, Borgas P, Kremers CJP, Bunday KL, Rothwell J, Duffell LD. The Immediate and Short-Term Effects of Transcutaneous Spinal Cord Stimulation and Peripheral Nerve Stimulation on Corticospinal Excitability. Front Neurosci 2021; 15:749042. [PMID: 34744614 PMCID: PMC8566815 DOI: 10.3389/fnins.2021.749042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 09/27/2021] [Indexed: 12/17/2022] Open
Abstract
Rehabilitative interventions involving electrical stimulation show promise for neuroplastic recovery in people living with Spinal Cord Injury (SCI). However, the understanding of how stimulation interacts with descending and spinal excitability remain unclear. In this study we compared the immediate and short-term (within a few minutes) effects of pairing Transcranial Magnetic Stimulation (TMS) with transcutaneous Spinal Cord stimulation (tSCS) and Peripheral Nerve Stimulation (PNS) on Corticospinal excitability in healthy subjects. Three separate experimental conditions were assessed. In Experiment I, paired associative stimulation (PAS) was applied, involving repeated pairing of single pulses of TMS and tSCS, either arriving simultaneously at the spinal motoneurones (PAS0ms) or slightly delayed (PAS5ms). Corticospinal and spinal excitability, and motor performance, were assessed before and after the PAS interventions in 24 subjects. Experiment II compared the immediate effects of tSCS and PNS on corticospinal excitability in 20 subjects. Experiment III compared the immediate effects of tSCS with tSCS delivered at the same stimulation amplitude but modulated with a carrier frequency (in the kHz range) on corticospinal excitability in 10 subjects. Electromyography (EMG) electrodes were placed over the Tibialis Anterior (TA) soleus (SOL) and vastus medialis (VM) muscles and stimulation electrodes (cathodes) were placed on the lumbar spine (tSCS) and lateral to the popliteal fossa (PNS). TMS over the primary motor cortex (M1) was paired with tSCS or PNS to produce Motor Evoked Potentials (MEPs) in the TA and SOL muscles. Simultaneous delivery of repetitive PAS (PAS0ms) increased corticospinal excitability and H-reflex amplitude at least 5 min after the intervention, and dorsiflexion force was increased in a force-matching task. When comparing effects on descending excitability between tSCS and PNS, a subsequent facilitation in MEPs was observed following tSCS at 30-50 ms which was not present following PNS. To a lesser extent this facilitatory effect was also observed with HF- tSCS at subthreshold currents. Here we have shown that repeated pairing of TMS and tSCS can increase corticospinal excitability when timed to arrive simultaneously at the alpha-motoneurone and can influence functional motor output. These results may be useful in optimizing stimulation parameters for neuroplasticity in people living with SCI.
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Affiliation(s)
- Yazi Al'joboori
- Department of Medical Physics & Biomedical Engineering, University College London, London, United Kingdom
| | - Ricci Hannah
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
| | - Francesca Lenham
- Department of Medical Physics & Biomedical Engineering, University College London, London, United Kingdom
| | - Pia Borgas
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
| | - Charlotte J P Kremers
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
| | - Karen L Bunday
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom.,Psychology, School of Social Sciences, University of Westminster, London, United Kingdom
| | - John Rothwell
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
| | - Lynsey D Duffell
- Department of Medical Physics & Biomedical Engineering, University College London, London, United Kingdom
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Seáñez I, Capogrosso M. Motor improvements enabled by spinal cord stimulation combined with physical training after spinal cord injury: review of experimental evidence in animals and humans. Bioelectron Med 2021; 7:16. [PMID: 34706778 PMCID: PMC8555080 DOI: 10.1186/s42234-021-00077-5] [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: 09/07/2021] [Accepted: 09/30/2021] [Indexed: 12/20/2022] Open
Abstract
Electrical spinal cord stimulation (SCS) has been gaining momentum as a potential therapy for motor paralysis in consequence of spinal cord injury (SCI). Specifically, recent studies combining SCS with activity-based training have reported unprecedented improvements in motor function in people with chronic SCI that persist even without stimulation. In this work, we first provide an overview of the critical scientific advancements that have led to the current uses of SCS in neurorehabilitation: e.g. the understanding that SCS activates dormant spinal circuits below the lesion by recruiting large-to-medium diameter sensory afferents within the posterior roots. We discuss how this led to the standardization of implant position which resulted in consistent observations by independent clinical studies that SCS in combination with physical training promotes improvements in motor performance and neurorecovery. While all reported participants were able to move previously paralyzed limbs from day 1, recovery of more complex motor functions was gradual, and the timeframe for first observations was proportional to the task complexity. Interestingly, individuals with SCI classified as AIS B and C regained motor function in paralyzed joints even without stimulation, but not individuals with motor and sensory complete SCI (AIS A). Experiments in animal models of SCI investigating the potential mechanisms underpinning this neurorecovery suggest a synaptic reorganization of cortico-reticulo-spinal circuits that correlate with improvements in voluntary motor control. Future experiments in humans and animal models of paralysis will be critical to understand the potential and limits for functional improvements in people with different types, levels, timeframes, and severities of SCI.
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Affiliation(s)
- Ismael Seáñez
- Biomedical Engineering, Washington University in St. Louis, St. Louis, USA. .,Neurosurgery, Washington University School of Medicine in St. Louis, St. Louis, USA.
| | - Marco Capogrosso
- Neurological Surgery, University of Pittsburgh, Pittsburgh, USA.,Department of Physical Medicine and Rehabilitation, Rehab and Neural Engineering Labs, University of Pittsburgh, Pittsburgh, USA.,Department of Bioengineering, University of Pittsburgh, Pittsburgh, USA
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Hofstoetter US, Freundl B, Lackner P, Binder H. Transcutaneous Spinal Cord Stimulation Enhances Walking Performance and Reduces Spasticity in Individuals with Multiple Sclerosis. Brain Sci 2021; 11:brainsci11040472. [PMID: 33917893 PMCID: PMC8068213 DOI: 10.3390/brainsci11040472] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/31/2021] [Accepted: 04/06/2021] [Indexed: 12/16/2022] Open
Abstract
Gait dysfunction and spasticity are common debilitating consequences of multiple sclerosis (MS). Improvements of these motor impairments by lumbar transcutaneous spinal cord stimulation (tSCS) have been demonstrated in spinal cord injury. Here, we explored for the first time the motor effects of lumbar tSCS applied at 50 Hz for 30 min in 16 individuals with MS and investigated their temporal persistence post-intervention. We used a comprehensive protocol assessing walking ability, different presentations of spasticity, standing ability, manual dexterity, and trunk control. Walking ability, including walking speed and endurance, was significantly improved for two hours beyond the intervention and returned to baseline after 24 h. Muscle spasms, clonus duration, and exaggerated stretch reflexes were reduced for two hours, and clinically assessed lower-extremity muscle hypertonia remained at improved levels for 24 h post-intervention. Further, postural sway during normal standing with eyes open was decreased for two hours. No changes were detected in manual dexterity and trunk control. Our results suggest that transcutaneous lumbar SCS can serve as a clinically accessible method without known side effects that holds the potential for substantial clinical benefit across the disability spectrum of MS.
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Affiliation(s)
- Ursula S. Hofstoetter
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 1090 Vienna, Austria
- Correspondence:
| | - Brigitta Freundl
- Neurological Center, Klinik Penzing—Wiener Gesundheitsverbund, 1140 Vienna, Austria; (B.F.); (P.L.); (H.B.)
| | - Peter Lackner
- Neurological Center, Klinik Penzing—Wiener Gesundheitsverbund, 1140 Vienna, Austria; (B.F.); (P.L.); (H.B.)
| | - Heinrich Binder
- Neurological Center, Klinik Penzing—Wiener Gesundheitsverbund, 1140 Vienna, Austria; (B.F.); (P.L.); (H.B.)
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