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Rimac J, Jančuljak D, Kovač B, Jovičić M, Forjan J. Reflex Responses in Muscles of the Lower Extremities Elicited by Transcutaneous Stimulation of Cauda Equina: Part 1. Methodology and Normative Data. J Clin Neurophysiol 2024:00004691-990000000-00135. [PMID: 38857374 DOI: 10.1097/wnp.0000000000001088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2024] Open
Abstract
INTRODUCTION Transcutaneous electrical stimulation is used to stimulate the dorsal roots of the cauda equina. Multiple elicited responses recorded in the lower extremity muscles are called posterior root muscle reflexes (PRMRs). Normal PRMR values in the muscles of healthy lower extremities have yet to be determined. METHODS Thirty subjects without known lumbosacral spinal root illness were included in this study. Subsequently, they were subjected to transcutaneous electrical stimulation of the cauda equina. Posterior root muscle reflex was recorded in the four muscle groups of both lower extremities. We elicited multiple PRMR and examined their characteristics in order to establish normal electrophysiological parameter values. RESULTS Posterior root muscle reflex was successfully elicited in the tibialis anterior (96.7%), gastrocnemius (100%), quadriceps femoris (93.3%), and hamstring (96.7%). No statistically significant differences were found in the intensity of stimulation, latencies, or area under the PRMR between the right and left leg muscles. The area under PRMR varied significantly among the participants. Higher body weight and abdominal girth showed a significant positive correlation with stimulation intensity for eliciting PRMR, and a significant negative correlation with the area under PRMR. Older age showed a significant negative correlation with the success of eliciting PRMR and the area under the PRMR. CONCLUSIONS Posterior root muscle reflex is a noninvasive and successful method for eliciting selective reflex responses of cauda equina posterior roots. Obtained values could be used in future studies to evaluate the utility of this methodology in clinical practice. This methodology could improve testing of the proximal lumbosacral nervous system functional integrity.
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Affiliation(s)
- Julija Rimac
- Department of Neurology, National Memorial Hospital "Dr. Juraj Njavro" Vukovar, Vukovar, Croatia
| | - Davor Jančuljak
- Neurology Clinic, Osijek Clinical Hospital Center, Osijek, Croatia
- Department of Neurology and Neurosurgery, Faculty of Medicine Osijek, University of Josip Juraj Strossmayer in Osijek, Osijek, Croatia
| | - Biserka Kovač
- Neurology Clinic, Osijek Clinical Hospital Center, Osijek, Croatia
- Department of Neurology, Faculty of Dental Medicine and Health Osijek, University of Josip Juraj Strossmayer in Osijek, Osijek, Croatia; and
| | - Miloš Jovičić
- Department of Neurology, National Memorial Hospital "Dr. Juraj Njavro" Vukovar, Vukovar, Croatia
| | - Josipa Forjan
- Department of Quantitative Methods and Informatics, Faculty of Economics in Osijek, Josip Juraj Strossmayer University in Osijek, Osijek, Croatia
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Gravholt A, Pfenninger C, Grospretre S, Martin A, Lapole T. Do soleus responses to transcutaneous spinal cord stimulation show similar changes to H-reflex in response to Achilles tendon vibration? Eur J Appl Physiol 2024; 124:1821-1833. [PMID: 38252303 DOI: 10.1007/s00421-023-05406-x] [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: 06/11/2023] [Accepted: 12/17/2023] [Indexed: 01/23/2024]
Abstract
INTRODUCTION/PURPOSE Recently, the use of transcutaneous spinal cord stimulation (TSCS) has been proposed as a viable alternative to the H-reflex. The aim of the current study was to investigate to what extent the two modes of spinal cord excitability investigation would be similarly sensitive to the well-known vibration-induced depression. METHODS Fourteen healthy participants (8 men and 6 women; age: 26.7 ± 4.8 years) were engaged in the study. The right soleus H-reflex and TSCS responses were recorded at baseline (PRE), during right Achilles tendon vibration (VIB) and following 20 min of vibration exposure (POST-VIB). Care was taken to match H-reflex and TSCS responses amplitude at PRE and to maintain effective stimulus intensities constant throughout time points. RESULTS The statistical analysis showed a significant effect of time for the H-reflex, with VIB (13 ± 5% of maximal M-wave (Mmax) and POST-VIB (36 ± 4% of Mmax) values being lower than PRE-values (48 ± 6% of Mmax). Similarly, TSCS responses changed over time, VIB (9 ± 5% of Mmax) and POST-VIB (27 ± 5% of Mmax) values being lower than PRE-values (46 ± 6% of Mmax). Pearson correlation analyses revealed positive correlation between H-reflex and TSCS responses PRE-to-VIB changes, but not for PRE- to POST-VIB changes. CONCLUSION While the sensitivity of TSCS seems to be similar to the gold standard H-reflex to highlight the vibratory paradox, both responses showed different sensitivity to the effects of prolonged vibration, suggesting slightly different pathways may actually contribute to evoked responses of both stimulation modalities.
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Affiliation(s)
- Anders Gravholt
- Université Jean Monnet Saint-Etienne, Lyon 1, Université Savoie Mont-Blanc, Laboratoire Interuniversitaire de Biologie de la Motricité, 42023, Saint-Etienne, France
| | - Clara Pfenninger
- Université Jean Monnet Saint-Etienne, Lyon 1, Université Savoie Mont-Blanc, Laboratoire Interuniversitaire de Biologie de la Motricité, 42023, Saint-Etienne, France
| | - Sidney Grospretre
- C3S Laboratory (Culture, Sport, , Health and Society; EA 4660), Department Sport & Performance, University of Franche-Comté, Besançon, France
| | - Alain Martin
- Laboratoire INSERM U1093, Université de Bourgogne, Faculté des Sciences du Sport (UFR Staps), BP 27877, 21078, Dijon, France
| | - Thomas Lapole
- Université Jean Monnet Saint-Etienne, Lyon 1, Université Savoie Mont-Blanc, Laboratoire Interuniversitaire de Biologie de la Motricité, 42023, Saint-Etienne, France.
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Nakagawa K, Kakehata G, Kaneko N, Masugi Y, Osu R, Iso S, Kanosue K, Nakazawa K. Reciprocal inhibition of the thigh muscles in humans: A study using transcutaneous spinal cord stimulation. Physiol Rep 2024; 12:e16039. [PMID: 38740563 DOI: 10.14814/phy2.16039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 04/11/2024] [Accepted: 04/19/2024] [Indexed: 05/16/2024] Open
Abstract
Evaluating reciprocal inhibition of the thigh muscles is important to investigate the neural circuits of locomotor behaviors. However, measurements of reciprocal inhibition of thigh muscles using spinal reflex, such as H-reflex, have never been systematically established owing to methodological limitations. The present study aimed to clarify the existence of reciprocal inhibition in the thigh muscles using transcutaneous spinal cord stimulation (tSCS). Twenty able-bodied male individuals were enrolled. We evoked spinal reflex from the biceps femoris muscle (BF) by tSCS on the lumber posterior root. We examined whether the tSCS-evoked BF reflex was reciprocally inhibited by the following conditionings: (1) single-pulse electrical stimulation on the femoral nerve innervating the rectus femoris muscle (RF) at various inter-stimulus intervals in the resting condition; (2) voluntary contraction of the RF; and (3) vibration stimulus on the RF. The BF reflex was significantly inhibited when the conditioning electrical stimulation was delivered at 10 and 20 ms prior to tSCS, during voluntary contraction of the RF, and during vibration on the RF. These data suggested a piece of evidence of the existence of reciprocal inhibition from the RF to the BF muscle in humans and highlighted the utility of methods for evaluating reciprocal inhibition of the thigh muscles using tSCS.
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Affiliation(s)
- Kento Nakagawa
- Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama, Japan
- Faculty of Human Sciences, Waseda University, Tokorozawa, Saitama, Japan
- Department of Sports and Health Management, Faculty of Business and Information Sciences, Jobu University, Isesaki, Gunma, Japan
| | - Gaku Kakehata
- Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama, Japan
- Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo, Japan
- Japan Society for the Promotion of Science, Chiyoda-ku, Tokyo, Japan
| | - Naotsugu Kaneko
- Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo, Japan
| | - Yohei Masugi
- Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo, Japan
- Department of Physical Therapy, School of Health Sciences, Tokyo International University, Kawagoe, Saitama, Japan
| | - Rieko Osu
- Faculty of Human Sciences, Waseda University, Tokorozawa, Saitama, Japan
| | - Shigeo Iso
- Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama, Japan
| | - Kazuyuki Kanosue
- Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama, Japan
- Institute of Health and Sports Science and Medicine, Juntendo University, Inzai, Chiba, Japan
| | - Kimitaka Nakazawa
- Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo, Japan
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Kawai K, Tazoe T, Yanai T, Kazuyuki K, Nishimura Y. Transsynaptic activation of human lumbar spinal motoneurons by transvertebral magnetic stimulation. Neurosci Res 2024; 200:20-27. [PMID: 37793496 DOI: 10.1016/j.neures.2023.10.001] [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: 08/14/2023] [Revised: 09/15/2023] [Accepted: 10/01/2023] [Indexed: 10/06/2023]
Abstract
Noninvasive spinal stimulation has been increasingly used in research on motor control and neurorehabilitation. Despite advances in percutaneous electrical stimulation techniques, magnetic stimulation is not as commonly used as electrical stimulation. Therefore, it is still under discussion what neuronal elements are activated by magnetic stimulation of the human spinal cord. In this study, we demonstrated that transvertebral magnetic stimulation (TVMS) induced transsynaptic activation of spinal motoneuron pools in the lumbar cord. In healthy humans, paired-pulse TVMS was given over an intervertebral space between the L1-L2 vertebrae with an interpulse interval of 100 ms, and the stimulus-evoked electromyographic (EMG) responses were recorded in the lower limb muscles. The results show that the evoked EMG responses after the 2nd pulse were clearly suppressed compared with the widespread responses evoked after the 1st pulse in the muscles of the lower extremity, indicating that the transsynaptic activation of spinal motoneurons by the 2nd pulse was suppressed by the effects produced by the 1st pulse. The inconsistent modulation of response suppression to stimulus intensity across individuals suggests that the TVMS-evoked EMG responses are composed of the compound potentials mediated by the direct activation of motor axons and the transsynaptic activation of motoneuron pools through sensory afferents and that the recruitment order of those fibers by TVMS may be nonhomogeneous across individuals.
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Affiliation(s)
- Kazutake Kawai
- College of Sports Sciences, Nihon University, Setagaya, Tokyo 154-8513, Japan; Neural Prosthetics Project, Department of Brain and Neuroscience, Tokyo Metropolitan Institute of Medical Science, Setagaya, Tokyo 156-8506, Japan; Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama 359-1192, Japan
| | - Toshiki Tazoe
- Neural Prosthetics Project, Department of Brain and Neuroscience, Tokyo Metropolitan Institute of Medical Science, Setagaya, Tokyo 156-8506, Japan.
| | - Toshimasa Yanai
- Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama 359-1192, Japan
| | - Kanosue Kazuyuki
- Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama 359-1192, Japan
| | - Yukio Nishimura
- Neural Prosthetics Project, Department of Brain and Neuroscience, Tokyo Metropolitan Institute of Medical Science, Setagaya, Tokyo 156-8506, Japan
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Massey S, Konig D, Upadhyay P, Evcil ZB, Melin R, Fatima M, Hannah R, Duffell L. The effects of transcutaneous spinal cord stimulation delivered with and without high-frequency modulation on spinal and corticospinal excitability. Artif Organs 2024; 48:297-308. [PMID: 37840354 DOI: 10.1111/aor.14660] [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: 02/23/2023] [Revised: 09/14/2023] [Accepted: 09/25/2023] [Indexed: 10/17/2023]
Abstract
Transcutaneous spinal cord stimulation (TSCS) has been shown to improve motor recovery in people with spinal cord injury (SCI). Some groups deliver TSCS modulated with a kHz-frequency (TSCS-kHz); the intensity used for TSCS-kHz is usually set based on the motor threshold for TSCS, even though TSCS-kHz threshold is considerably higher than TSCS. As a result, TSCS-kHz interventions tend to be delivered at low intensities with respect to the motor threshold (~40%). In this study, we compared the effects of sub-threshold TSCS and TSCS-kHz, when delivered at similar intensity relative to their own motor threshold. Experiment I compared the after-effects of 20 min of sub-threshold (40% threshold) TSCS and TSCS-kHz on spinal and corticospinal excitability in able-bodied participants. Experiment II assessed the dose-response relationship of delivering short (10-pulse) trains of TSCS and TSCS-kHz at three different current intensities relative to the threshold (40%, 60%, and 80%). Experiment I found that 20 min of TSCS-kHz at a 40% threshold decreased posterior root reflex amplitude (p < 0.05), whereas TSCS did not. In experiment II, motor-evoked potential (MEP) amplitude increased following short trains of TSCS and TSCS-kHz of increasing intensity. MEP amplitude was significantly greater for TSCS-kHz compared with TSCS when delivered at 80% of the threshold (p < 0.05). These results suggest that TSCS and TSCS-kHz have different effects when delivered at similar intensity relative to their own threshold; both for immediate effects on corticospinal excitability and following prolonged stimulation on spinal excitability. These different effects may be utilized for optimal rehabilitation in people with SCI.
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Affiliation(s)
- Sarah Massey
- Department of Medical Physics & Biomedical Engineering, University College London, London, UK
- Aspire Centre for Rehabilitation Engineering and Assistive Technology, UCL Institute of Orthopaedics and Musculoskeletal Sciences, Royal National Orthopaedic Hospital, London, UK
| | - Danielle Konig
- Department of Medical Physics & Biomedical Engineering, University College London, London, UK
| | - Pratham Upadhyay
- Department of Medical Physics & Biomedical Engineering, University College London, London, UK
| | - Zehra Beril Evcil
- Department of Medical Physics & Biomedical Engineering, University College London, London, UK
| | - Rebbekha Melin
- Department of Medical Physics & Biomedical Engineering, University College London, London, UK
| | - Memoona Fatima
- Department of Medical Physics & Biomedical Engineering, University College London, London, UK
| | - Ricci Hannah
- Centre for Human and Applied Physiological Sciences, Kings College London, London, UK
| | - Lynsey Duffell
- Department of Medical Physics & Biomedical Engineering, University College London, London, UK
- Aspire Centre for Rehabilitation Engineering and Assistive Technology, UCL Institute of Orthopaedics and Musculoskeletal Sciences, Royal National Orthopaedic Hospital, London, UK
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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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Omofuma I, Carrera R, King-Ori J, Agrawal SK. The effect of transcutaneous spinal cord stimulation on the balance and neurophysiological characteristics of young healthy adults. WEARABLE TECHNOLOGIES 2024; 5:e3. [PMID: 38486863 PMCID: PMC10936317 DOI: 10.1017/wtc.2023.24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 09/01/2023] [Accepted: 10/31/2023] [Indexed: 03/17/2024]
Abstract
Transcutaneous spinal cord stimulation (TSCS) is gaining popularity as a noninvasive alternative to epidural stimulation. However, there is still much to learn about its effects and utility in assisting recovery of motor control. In this study, we applied TSCS to healthy subjects concurrently performing a functional training task to study its effects during a training intervention. We first carried out neurophysiological tests to characterize the H-reflex, H-reflex recovery, and posterior root muscle reflex thresholds, and then conducted balance tests, first without TSCS and then with TSCS. Balance tests included trunk perturbations in forward, backward, left, and right directions, and subjects' balance was characterized by their response to force perturbations. A balance training task involved the subjects playing a catch-and-throw game in virtual reality (VR) while receiving trunk perturbations and TSCS. Balance tests with and without TSCS were conducted after the VR training to measure subjects' post-training balance characteristics and then neurophysiological tests were carried out again. Statistical comparisons using t-tests between the balance and neurophysiological data collected before and after the VR training intervention found that the immediate effect of TSCS was to increase muscle activity during forward perturbations and to reduce balance performance in that direction. Muscle activity decreased after training and even more once TSCS was turned off. We thus observed an interaction of effects where TSCS increased muscle activity while the physical training decreased it.
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Affiliation(s)
- Isirame Omofuma
- Mechanical Engineering Department, Columbia University, New York, NY, USA
| | - Robert Carrera
- Mechanical Engineering Department, Columbia University, New York, NY, USA
| | | | - Sunil K Agrawal
- Mechanical Engineering Department, Columbia University, New York, NY, USA
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Spieker EL, Dvorani A, Salchow-Hömmen C, Otto C, Ruprecht K, Wenger N, Schauer T. Targeting Transcutaneous Spinal Cord Stimulation Using a Supervised Machine Learning Approach Based on Mechanomyography. SENSORS (BASEL, SWITZERLAND) 2024; 24:634. [PMID: 38276326 PMCID: PMC10818383 DOI: 10.3390/s24020634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 01/14/2024] [Accepted: 01/17/2024] [Indexed: 01/27/2024]
Abstract
Transcutaneous spinal cord stimulation (tSCS) provides a promising therapy option for individuals with injured spinal cords and multiple sclerosis patients with spasticity and gait deficits. Before the therapy, the examiner determines a suitable electrode position and stimulation current for a controlled application. For that, amplitude characteristics of posterior root muscle (PRM) responses in the electromyography (EMG) of the legs to double pulses are examined. This laborious procedure holds potential for simplification due to time-consuming skin preparation, sensor placement, and required expert knowledge. Here, we investigate mechanomyography (MMG) that employs accelerometers instead of EMGs to assess muscle activity. A supervised machine-learning classification approach was implemented to classify the acceleration data into no activity and muscular/reflex responses, considering the EMG responses as ground truth. The acceleration-based calibration procedure achieved a mean accuracy of up to 87% relative to the classical EMG approach as ground truth on a combined cohort of 11 healthy subjects and 11 patients. Based on this classification, the identified current amplitude for the tSCS therapy was in 85%, comparable to the EMG-based ground truth. In healthy subjects, where both therapy current and position have been identified, 91% of the outcome matched well with the EMG approach. We conclude that MMG has the potential to make the tuning of tSCS feasible in clinical practice and even in home use.
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Affiliation(s)
- Eira Lotta Spieker
- Department of Neurology, Charité–Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; (E.L.S.); (C.S.-H.); (C.O.); (K.R.); (N.W.)
- Control Systems Group, Technische Universität Berlin, Einsteinufer 17, 10587 Berlin, Germany;
- SensorStim Neurotechnology GmbH, c/o TU Berlin, Einsteinufer 17, 10587 Berlin, Germany
| | - Ardit Dvorani
- Control Systems Group, Technische Universität Berlin, Einsteinufer 17, 10587 Berlin, Germany;
- SensorStim Neurotechnology GmbH, c/o TU Berlin, Einsteinufer 17, 10587 Berlin, Germany
| | - Christina Salchow-Hömmen
- Department of Neurology, Charité–Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; (E.L.S.); (C.S.-H.); (C.O.); (K.R.); (N.W.)
| | - Carolin Otto
- Department of Neurology, Charité–Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; (E.L.S.); (C.S.-H.); (C.O.); (K.R.); (N.W.)
| | - Klemens Ruprecht
- Department of Neurology, Charité–Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; (E.L.S.); (C.S.-H.); (C.O.); (K.R.); (N.W.)
| | - Nikolaus Wenger
- Department of Neurology, Charité–Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany; (E.L.S.); (C.S.-H.); (C.O.); (K.R.); (N.W.)
| | - Thomas Schauer
- Control Systems Group, Technische Universität Berlin, Einsteinufer 17, 10587 Berlin, Germany;
- SensorStim Neurotechnology GmbH, c/o TU Berlin, Einsteinufer 17, 10587 Berlin, Germany
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Tran K, Steele A, Crossnoe R, Martin C, Sayenko DG. Multi-site lumbar transcutaneous spinal cord stimulation: When less is more. Neurosci Lett 2024; 820:137579. [PMID: 38096973 PMCID: PMC10872491 DOI: 10.1016/j.neulet.2023.137579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 11/15/2023] [Accepted: 12/04/2023] [Indexed: 12/17/2023]
Abstract
BACKGROUND Transcutaneous spinal stimulation (TSS) has become a valuable tool for facilitating rehabilitation in individuals with neurological deficits. A significant constraint arises from the need for precise knowledge of stimulation locations to effectively apply TSS for targeted functional enhancement. METHODS In this study, we investigate whether single-site or simultaneous multi-site stimulation over the lumbar spinal cord is advantageous for recruitment of specific motor pools projecting to lower limb muscles and generates higher leg extensor forces in neurologically intact individuals. Tests were performed in a supine position. TSS was delivered at T10-T11, T11-T12, T12-L1, and L1-L2 intervertebral spaces individually, then through all four locations simultaneously. The peak-to-peak amplitude of spinally evoked motor potentials and the forces generated by lower limb muscles were compared at the common motor threshold intensity level across all stimulation conditions. RESULTS Recruitment of motor pools projecting to proximal and distal lower limb muscles followed their topographical rostro-caudal arrangement along the lumbosacral enlargement. Single-site stimulation, apart from the T10-T11 location, resulted in larger responses in both proximal and distal muscles while also generating higher knee-extension and plantarflexion forces when compared to multi-site stimulation. CONCLUSIONS Both motor response and force generation were reduced when using multi-site TSS when compared to single-site stimulation. This demonstrates that the segmental effects of TSS are important to consider when performing multi-site TSS.
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Affiliation(s)
- Khue Tran
- School of Engineering Medicine, Texas A&M University, Houston, TX, USA
| | - Alexander Steele
- Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX, USA
| | - Remington Crossnoe
- Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX, USA
| | - Catherine Martin
- Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX, USA
| | - Dimitry G Sayenko
- Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX, 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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12
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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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13
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Fleming N, Taylor C, Etzelmueller M, Gill C, O’Keeffe C, Mahony N, Reilly RB. Contralateral Selectivity of Upper-Limb Motor Pools via Targeted Stimulation of the Cervical Spinal Cord. Biomedicines 2023; 11:biomedicines11020332. [PMID: 36830867 PMCID: PMC9952898 DOI: 10.3390/biomedicines11020332] [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: 08/16/2022] [Revised: 01/05/2023] [Accepted: 01/13/2023] [Indexed: 01/26/2023] Open
Abstract
Transcutaneous spinal cord stimulation (tSCS) at the cervical level may facilitate improved upper-limb function in those with incomplete tetraplegia. While clinical trials are ongoing, there is still much debate regarding the transmission pathway as well as appropriate stimulation parameters. This study aimed to explore the extent to which cervical tSCS can induce mono-synaptic reflexes in discrete upper-limb motor pools and examine the effects of altering stimulus location and intensity. METHODS Fourteen participants with intact nervous systems completed two laboratory visits, during which posterior root-muscle reflexes (PRMRs) were evoked via a 3 × 3 cathode matrix applied over the cervical spine. An incremental recruitment curve at the C7 vertebral level was initially performed to attain resting motor threshold (RMT) in each muscle. Paired pulses (1 ms square monophasic with inter-pulse interval of 50 ms) were subsequently delivered at a frequency of 0.25 Hz at two intensities (RMT and RMT + 20%) across all nine cathode positions. Evoked responses to the 1st (PRMR1) and 2nd (PRMR2) stimuli were recorded in four upper-limb muscles. RESULTS A significant effect of the spinal level was observed in all muscles for PRMR1, with greater responses being recorded caudally. Contralateral stimulation significantly increased PRMR1 in Biceps Brachii (p < 0.05, F = 4.9, η2 = 0.29), Flexor Carpi Radialis (p < 0.05, F = 4.9, η2 = 0.28) and Abductor Pollicis Brevis (p < 0.01, F = 8.9, η2 = 0.89). Post-activation depression (PAD) was also significantly increased with contralateral stimulation in Biceps Brachii (p = 0.001, F = 9.3, η2 = 0.44), Triceps Brachii (p < 0.05, F = 5.4, η2 = 0.31) and Flexor Carpi Radialis (p < 0.001, F = 17.4, η2 = 0.59). CONCLUSIONS A level of unilateral motor pool selectivity may be attained by altering stimulus intensity and location during cervical tSCS. Optimising these parameters may improve the efficacy of this neuromodulation method in clinical cohorts.
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Affiliation(s)
- Neil Fleming
- Discipline of Anatomy, School of Medicine, Trinity College Dublin, D02 R590 Dublin, Ireland
- Correspondence: ; Tel.: +353-18961412
| | - Clare Taylor
- Discipline of Anatomy, School of Medicine, Trinity College Dublin, D02 R590 Dublin, Ireland
| | - Mark Etzelmueller
- School of Engineering, Trinity College, The University of Dublin, D08 XW7X Dublin, Ireland
- Discipline of Gerontology School of Medicine, Trinity College, The University of Dublin, D02 R590 Dublin, Ireland
| | - Conor Gill
- School of Engineering, Trinity College, The University of Dublin, D08 XW7X Dublin, Ireland
- Discipline of Gerontology School of Medicine, Trinity College, The University of Dublin, D02 R590 Dublin, Ireland
| | - Clodagh O’Keeffe
- School of Engineering, Trinity College, The University of Dublin, D08 XW7X Dublin, Ireland
- Discipline of Gerontology School of Medicine, Trinity College, The University of Dublin, D02 R590 Dublin, Ireland
| | - Nicholas Mahony
- Discipline of Anatomy, School of Medicine, Trinity College Dublin, D02 R590 Dublin, Ireland
| | - Richard B. Reilly
- School of Engineering, Trinity College, The University of Dublin, D08 XW7X Dublin, Ireland
- Discipline of Gerontology School of Medicine, Trinity College, The University of Dublin, D02 R590 Dublin, Ireland
- Trinity Centre for Biomedical Engineering, Trinity College Dublin, D02 R590 Dublin, Ireland
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14
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Dalrymple AN, Hooper CA, Kuriakose MG, Capogrosso M, Weber DJ. Using a high-frequency carrier does not improve comfort of transcutaneous spinal cord stimulation. J Neural Eng 2023; 20. [PMID: 36595241 DOI: 10.1088/1741-2552/acabe8] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022]
Abstract
Objective.Spinal cord neuromodulation has gained much attention for demonstrating improved motor recovery in people with spinal cord injury, motivating the development of clinically applicable technologies. Among them, transcutaneous spinal cord stimulation (tSCS) is attractive because of its non-invasive profile. Many tSCS studies employ a high-frequency (10 kHz) carrier, which has been reported to reduce stimulation discomfort. However, these claims have come under scrutiny in recent years. The purpose of this study was to determine whether using a high-frequency carrier for tSCS is more comfortable at therapeutic amplitudes, which evoke posterior root-muscle (PRM) reflexes.Approach.In 16 neurologically intact participants, tSCS was delivered using a 1 ms long monophasic pulse with and without a high-frequency carrier. Stimulation amplitude and pulse duration were varied and PRM reflexes were recorded from the soleus, gastrocnemius, and tibialis anterior muscles. Participants rated their discomfort during stimulation from 0 to 10 at PRM reflex threshold.Main Results.At PRM reflex threshold, the addition of a high-frequency carrier (0.87 ± 0.2) was equally comfortable as conventional stimulation (1.03 ± 0.18) but required approximately double the charge to evoke the PRM reflex (conventional: 32.4 ± 9.2µC; high-frequency carrier: 62.5 ± 11.1µC). Strength-duration curves for tSCS with a high-frequency carrier had a rheobase that was 4.8× greater and a chronaxie that was 5.7× narrower than the conventional monophasic pulse, indicating that the addition of a high-frequency carrier makes stimulation less efficient in recruiting neural activity in spinal roots.Significance.Using a high-frequency carrier for tSCS is equally as comfortable and less efficient as conventional stimulation at amplitudes required to stimulate spinal dorsal roots.
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Affiliation(s)
- Ashley N Dalrymple
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, United States of America.,NeuroMechatronics Lab, Carnegie Mellon University, Pittsburgh, PA, United States of America
| | - Charli Ann Hooper
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, United States of America.,NeuroMechatronics Lab, Carnegie Mellon University, Pittsburgh, PA, United States of America.,Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, United States of America
| | - Minna G Kuriakose
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America.,Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Marco Capogrosso
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America.,Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, PA, United States of America.,Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, United States of America.,Center for Neural Basis of Cognition, Pittsburgh, PA, United States of America
| | - Douglas J Weber
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, United States of America.,NeuroMechatronics Lab, Carnegie Mellon University, Pittsburgh, PA, United States of America.,Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, United States of America
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15
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McGeady C, Vučković A, Singh Tharu N, Zheng YP, Alam M. Brain-Computer Interface Priming for Cervical Transcutaneous Spinal Cord Stimulation Therapy: An Exploratory Case Study. FRONTIERS IN REHABILITATION SCIENCES 2022; 3:896766. [PMID: 36188944 PMCID: PMC9397879 DOI: 10.3389/fresc.2022.896766] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 06/01/2022] [Indexed: 06/01/2023]
Abstract
Loss of arm and hand function is one of the most devastating consequences of cervical spinal cord injury (SCI). Although some residual functional neurons often pass the site of injury, recovery after SCI is extremely limited. Recent efforts have aimed to augment traditional rehabilitation by combining exercise-based training with techniques such as transcutaneous spinal cord stimulation (tSCS), and movement priming. Such methods have been linked with elevated corticospinal excitability, and enhanced neuroplastic effects following activity-based therapy. In the present study, we investigated the potential for facilitating tSCS-based exercise-training with brain-computer interface (BCI) motor priming. An individual with chronic AIS A cervical SCI with both sensory and motor complete tetraplegia participated in a two-phase cross-over intervention whereby they engaged in 15 sessions of intensive tSCS-mediated hand training for 1 h, 3 times/week, followed by a two week washout period, and a further 15 sessions of tSCS training with bimanual BCI motor priming preceding each session. We found using the Graded Redefined Assessment for Strength, Sensibility, and Prehension that the participant's arm and hand function improved considerably across each phase of the study: from 96/232 points at baseline, to 117/232 after tSCS training alone, and to 131/232 points after BCI priming with tSCS training, reflecting improved strength, sensation, and gross and fine motor skills. Improved motor scores and heightened perception to sharp sensations improved the neurological level of injury from C4 to C5 following training and improvements were generally maintained four weeks after the final training session. Although functional improvements were similar regardless of the presence of BCI priming, there was a moderate improvement of bilateral strength only when priming preceded tSCS training, perhaps suggesting a benefit of motor priming for tSCS training.
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Affiliation(s)
- Ciarán McGeady
- Centre for Rehabilitation Engineering, University of Glasgow, Glasgow, United Kingdom
| | - Aleksandra Vučković
- Centre for Rehabilitation Engineering, University of Glasgow, Glasgow, United Kingdom
| | - Niraj Singh Tharu
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China
| | - Yong-Ping Zheng
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China
| | - Monzurul Alam
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China
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16
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Transcutaneous spinal stimulation alters cortical and subcortical activation patterns during mimicked-standing: A proof-of-concept fMRI study. NEUROIMAGE: REPORTS 2022; 2. [DOI: 10.1016/j.ynirp.2022.100090] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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17
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Calvert JS, Darie R, Parker SR, Shaaya E, Syed S, McLaughlin BL, Fridley JS, Borton DA. Spatiotemporal Distribution of Electrically Evoked Spinal Compound Action Potentials During Spinal Cord Stimulation. Neuromodulation 2022:S1094-7159(22)00644-4. [PMID: 35551869 PMCID: PMC9643656 DOI: 10.1016/j.neurom.2022.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 03/07/2022] [Accepted: 03/23/2022] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Recent studies using epidural spinal cord stimulation (SCS) have demonstrated restoration of motor function in individuals previously diagnosed with chronic spinal cord injury (SCI). In parallel, the spinal evoked compound action potentials (ECAPs) induced by SCS have been used to gain insight into the mechanisms of SCS-based chronic pain therapy and to titrate closed-loop delivery of stimulation. However, the previous characterization of ECAPs recorded during SCS was performed with one-dimensional, cylindrical electrode leads. Herein, we describe the unique spatiotemporal distribution of ECAPs induced by SCS across the medial-lateral and rostral-caudal axes of the spinal cord, and their relationship to polysynaptic lower-extremity motor activation. MATERIALS AND METHODS In each of four sheep, two 24-contact epidural SCS arrays were placed on the lumbosacral spinal cord, spanning the L3 to L6 vertebrae. Spinal ECAPs were recorded during SCS from nonstimulating contacts of the epidural arrays, which were synchronized to bilateral electromyography (EMG) recordings from six back and lower-extremity muscles. RESULTS We observed a triphasic P1, N1, P2 peak morphology and propagation in the ECAPs during midline and lateral stimulation. Distinct regions of lateral stimulation resulted in simultaneously increased ECAP and EMG responses compared with stimulation at adjacent lateral contacts. Although EMG responses decreased during repetitive stimulation bursts, spinal ECAP amplitude did not significantly change. Both spinal ECAP responses and EMG responses demonstrated preferential ipsilateral recruitment during lateral stimulation compared with midline stimulation. Furthermore, EMG responses were correlated with stimulation that resulted in increased ECAP amplitude on the ipsilateral side of the electrode array. CONCLUSIONS These results suggest that ECAPs can be used to investigate the effects of SCS on spinal sensorimotor networks and to inform stimulation strategies that optimize the clinical benefit of SCS in the context of managing chronic pain and the restoration of sensorimotor function after SCI.
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Affiliation(s)
- Jonathan S Calvert
- Center for Biomedical Engineering, School of Engineering, Brown University, Providence, RI, USA
| | - Radu Darie
- Center for Biomedical Engineering, School of Engineering, Brown University, Providence, RI, USA
| | - Samuel R Parker
- Center for Biomedical Engineering, School of Engineering, Brown University, Providence, RI, USA
| | - Elias Shaaya
- Department of Neurosurgery, Brown University and Rhode Island Hospital, Providence, RI, USA
| | - Sohail Syed
- Department of Neurosurgery, Brown University and Rhode Island Hospital, Providence, RI, USA
| | | | - Jared S Fridley
- Department of Neurosurgery, Brown University and Rhode Island Hospital, Providence, RI, USA
| | - David A Borton
- Center for Biomedical Engineering, School of Engineering, Brown University, Providence, RI, USA; Department of Veterans Affairs, Center for Neurorestoration and Neurotechnology, Providence, RI, USA; Carney Institute for Brain Science, Brown University, Providence, RI, USA.
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18
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Atkinson DA, Steele AG, Manson GA, Sheynin J, Oh J, Gerasimenko YP, Sayenko DG. Characterization of interlimb interaction via transcutaneous spinal stimulation of cervical and lumbar spinal enlargements. J Neurophysiol 2022; 127:1075-1085. [PMID: 35320019 PMCID: PMC8993515 DOI: 10.1152/jn.00456.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 03/17/2022] [Accepted: 03/21/2022] [Indexed: 11/22/2022] Open
Abstract
The use of transcutaneous electrical spinal stimulation (TSS) to modulate sensorimotor networks after neurological insult has garnered much attention from both researchers and clinicians in recent years. Although many different stimulation paradigms have been reported, the interlimb effects of these neuromodulation techniques have been little studied. The effects of multisite TSS on interlimb sensorimotor function are of particular interest in the context of neurorehabilitation, as these networks have been shown to be important for functional recovery after neurological insult. The present study utilized a condition-test paradigm to investigate the effects of interenlargement TSS on spinal motor excitability in both cervical and lumbosacral motor pools. Additionally, comparison was made between the conditioning effects of lumbosacral and cervical TSS and peripheral stimulation of the fibular nerve and ulnar nerve, respectively. In 16/16 supine, relaxed participants, facilitation of spinally evoked motor responses (sEMRs) in arm muscles was seen in response to lumbosacral TSS or fibular nerve stimulation, whereas facilitation of sEMRs in leg muscles was seen in response to cervical TSS or ulnar nerve stimulation. The decreased latency between TSS- and peripheral nerve-evoked conditioning implicates interlimb networks in the observed facilitation of motor output. The results demonstrate the ability of multisite TSS to engage interlimb networks, resulting in the bidirectional influence of cervical and lumbosacral motor output. The engagement of interlimb networks via TSS of the cervical and lumbosacral enlargements represents a feasible method for engaging spinal sensorimotor networks in clinical populations with compromised motor function.NEW & NOTEWORTHY Bidirectional interlimb modulation of spinal motor excitability can be evoked by transcutaneous spinal stimulation over the cervical and lumbosacral enlargements. Multisite transcutaneous spinal stimulation engages spinal sensorimotor networks thought to be important in the recovery of function after spinal cord injury.
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Affiliation(s)
- D. A. Atkinson
- Doctor of Physical Therapy program, University of St. Augustine for Health Sciences, Austin, Texas
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, Texas
| | - A. G. Steele
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, Texas
- Department of Electrical and Computer Engineering, University of Houston, Houston, Texas
| | - G. A. Manson
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, Texas
- School of Kinesiology and Health Studies, Queen’s University, Kingston, Ontario, Canada
| | - J. Sheynin
- Department of Psychiatry and Behavioral Science, Texas A&M University Health Science Center, Houston, Texas
| | - J. Oh
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, Texas
| | - Y. P. Gerasimenko
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky
- Department of Physiology, University of Louisville, Louisville, Kentucky
- Pavlov Institute of Physiology, St. Petersburg, Russia
| | - D. G. Sayenko
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, Texas
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19
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Effect of Cervical Transcutaneous Spinal Cord Stimulation on Sensorimotor Cortical Activity during Upper-Limb Movements in Healthy Individuals. J Clin Med 2022; 11:jcm11041043. [PMID: 35207314 PMCID: PMC8878243 DOI: 10.3390/jcm11041043] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 02/13/2022] [Accepted: 02/15/2022] [Indexed: 12/14/2022] Open
Abstract
Transcutaneous spinal cord stimulation (tSCS) can improve upper-limb motor function after spinal cord injury. A number of studies have attempted to deduce the corticospinal mechanisms which are modulated following tSCS, with many relying on transcranial magnetic stimulation to provide measures of corticospinal excitability. Other metrics, such as cortical oscillations, may provide an alternative and complementary perspective on the physiological effect of tSCS. Hence, the present study recorded EEG from 30 healthy volunteers to investigate if and how cortical oscillatory dynamics are altered by 10 min of continuous cervical tSCS. Participants performed repetitive upper-limb movements and resting-state tasks while tSCS was delivered to the posterior side of the neck as EEG was recorded simultaneously. The intensity of tSCS was tailored to each participant based on their maximum tolerance (mean: 50 ± 20 mA). A control session was conducted without tSCS. Changes to sensorimotor cortical activity during movement were quantified in terms of event-related (de)synchronisation (ERD/ERS). Our analysis revealed that, on a group level, there was no consistency in terms of the direction of ERD modulation during tSCS, nor was there a dose-effect between tSCS and ERD/ERS. Resting-state oscillatory power was compared before and after tSCS but no statistically significant difference was found in terms of alpha peak frequency or alpha power. However, participants who received the highest stimulation intensities had significantly weakened ERD/ERS (10% ERS) compared to when tSCS was not applied (25% ERD; p = 0.016), suggestive of cortical inhibition. Overall, our results demonstrated that a single 10 min session of tSCS delivered to the cervical region of the spine was not sufficient to induce consistent changes in sensorimotor cortical activity among the entire cohort. However, under high intensities there may be an inhibitory effect at the cortical level. Future work should investigate, with a larger sample size, the effect of session duration and tSCS intensity on cortical oscillations.
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Carrera RM, Omofuma I, Yasin B, Agrawal SK. The Effect of Transcutaneous Spinal Cord Stimulation on Standing Postural Control in Healthy Adults. IEEE Robot Autom Lett 2022. [DOI: 10.1109/lra.2022.3185370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Robert M. Carrera
- Department of Biomedical Engineering, Columbia University,, New York, NY, USA
| | - Isirame Omofuma
- Department of Biomedical Engineering, Columbia University,, New York, NY, USA
| | - Bushra Yasin
- Mechanical Engineering Department, Columbia University, New York, NY, USA
| | - Sunil K. Agrawal
- Departments of Mechanical Engineering and Rehabilitation and, Regenerative Medicine, New York, NY, USA
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21
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Steele AG, Atkinson DA, Varghese B, Oh J, Markley RL, Sayenko DG. Characterization of Spinal Sensorimotor Network Using Transcutaneous Spinal Stimulation during Voluntary Movement Preparation and Performance. J Clin Med 2021; 10:jcm10245958. [PMID: 34945253 PMCID: PMC8709482 DOI: 10.3390/jcm10245958] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 12/10/2021] [Accepted: 12/15/2021] [Indexed: 12/12/2022] Open
Abstract
Transcutaneous electrical spinal stimulation (TSS) can be used to selectively activate motor pools based on their anatomical arrangements in the lumbosacral enlargement. These spatial patterns of spinal motor activation may have important clinical implications, especially when there is a need to target specific muscle groups. However, our understanding of the net effects and interplay between the motor pools projecting to agonist and antagonist muscles during the preparation and performance of voluntary movements is still limited. The present study was designed to systematically investigate and differentiate the multi-segmental convergence of supraspinal inputs on the lumbosacral neural network before and during the execution of voluntary leg movements in neurologically intact participants. During the experiments, participants (N = 13) performed isometric (1) knee flexion and (2) extension, as well as (3) plantarflexion and (4) dorsiflexion. TSS consisting of a pair pulse with 50 ms interstimulus interval was delivered over the T12-L1 vertebrae during the muscle contractions, as well as within 50 to 250 ms following the auditory or tactile stimuli, to characterize the temporal profiles of net spinal motor output during movement preparation. Facilitation of evoked motor potentials in the ipsilateral agonists and contralateral antagonists emerged as early as 50 ms following the cue and increased prior to movement onset. These results suggest that the descending drive modulates the activity of the inter-neuronal circuitry within spinal sensorimotor networks in specific, functionally relevant spatiotemporal patterns, which has a direct implication for the characterization of the state of those networks in individuals with neurological conditions.
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Affiliation(s)
- Alexander G. Steele
- Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, 6550 Fannin Street, Houston, TX 77030, USA; (A.G.S.); (D.A.A.); (B.V.); (J.O.); (R.L.M.)
- Department of Electrical and Computer Engineering, University of Houston, E413 Engineering Bldg 2, 4726 Calhoun Road, Houston, TX 77204, USA
| | - Darryn A. Atkinson
- Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, 6550 Fannin Street, Houston, TX 77030, USA; (A.G.S.); (D.A.A.); (B.V.); (J.O.); (R.L.M.)
- College of Rehabilitative Sciences, University of St. Augustine for Health Sciences, 5401 La Crosse Avenue, Austin, TX 78739, USA
| | - Blesson Varghese
- Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, 6550 Fannin Street, Houston, TX 77030, USA; (A.G.S.); (D.A.A.); (B.V.); (J.O.); (R.L.M.)
| | - Jeonghoon Oh
- Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, 6550 Fannin Street, Houston, TX 77030, USA; (A.G.S.); (D.A.A.); (B.V.); (J.O.); (R.L.M.)
| | - Rachel L. Markley
- Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, 6550 Fannin Street, Houston, TX 77030, USA; (A.G.S.); (D.A.A.); (B.V.); (J.O.); (R.L.M.)
| | - Dimitry G. Sayenko
- Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, 6550 Fannin Street, Houston, TX 77030, USA; (A.G.S.); (D.A.A.); (B.V.); (J.O.); (R.L.M.)
- Correspondence: ; Tel.: +1-713-363-9910
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22
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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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24
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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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25
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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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26
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Calvert JS, Gill ML, Linde MB, Veith DD, Thoreson AR, Lopez C, Lee KH, Gerasimenko YP, Edgerton VR, Lavrov IA, Zhao KD, Grahn PJ, Sayenko DG. Voluntary Modulation of Evoked Responses Generated by Epidural and Transcutaneous Spinal Stimulation in Humans with Spinal Cord Injury. J Clin Med 2021; 10:jcm10214898. [PMID: 34768418 PMCID: PMC8584516 DOI: 10.3390/jcm10214898] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 10/20/2021] [Accepted: 10/20/2021] [Indexed: 12/29/2022] Open
Abstract
Transcutaneous (TSS) and epidural spinal stimulation (ESS) are electrophysiological techniques that have been used to investigate the interactions between exogenous electrical stimuli and spinal sensorimotor networks that integrate descending motor signals with afferent inputs from the periphery during motor tasks such as standing and stepping. Recently, pilot-phase clinical trials using ESS and TSS have demonstrated restoration of motor functions that were previously lost due to spinal cord injury (SCI). However, the spinal network interactions that occur in response to TSS or ESS pulses with spared descending connections across the site of SCI have yet to be characterized. Therefore, we examined the effects of delivering TSS or ESS pulses to the lumbosacral spinal cord in nine individuals with chronic SCI. During low-frequency stimulation, participants were instructed to relax or attempt maximum voluntary contraction to perform full leg flexion while supine. We observed similar lower-extremity neuromusculature activation during TSS and ESS when performed in the same participants while instructed to relax. Interestingly, when participants were instructed to attempt lower-extremity muscle contractions, both TSS- and ESS-evoked motor responses were significantly inhibited across all muscles. Participants with clinically complete SCI tested with ESS and participants with clinically incomplete SCI tested with TSS demonstrated greater ability to modulate evoked responses than participants with motor complete SCI tested with TSS, although this was not statistically significant due to a low number of subjects in each subgroup. These results suggest that descending commands combined with spinal stimulation may increase activity of inhibitory interneuronal circuitry within spinal sensorimotor networks in individuals with SCI, which may be relevant in the context of regaining functional motor outcomes.
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Affiliation(s)
- Jonathan S. Calvert
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN 55905, USA;
| | - Megan L. Gill
- Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, MN 55905, USA; (M.L.G.); (M.B.L.); (D.D.V.); (A.R.T.); (C.L.); (K.H.L.); (K.D.Z.); (P.J.G.)
| | - Margaux B. Linde
- Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, MN 55905, USA; (M.L.G.); (M.B.L.); (D.D.V.); (A.R.T.); (C.L.); (K.H.L.); (K.D.Z.); (P.J.G.)
| | - Daniel D. Veith
- Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, MN 55905, USA; (M.L.G.); (M.B.L.); (D.D.V.); (A.R.T.); (C.L.); (K.H.L.); (K.D.Z.); (P.J.G.)
| | - Andrew R. Thoreson
- Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, MN 55905, USA; (M.L.G.); (M.B.L.); (D.D.V.); (A.R.T.); (C.L.); (K.H.L.); (K.D.Z.); (P.J.G.)
| | - Cesar Lopez
- Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, MN 55905, USA; (M.L.G.); (M.B.L.); (D.D.V.); (A.R.T.); (C.L.); (K.H.L.); (K.D.Z.); (P.J.G.)
| | - Kendall H. Lee
- Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, MN 55905, USA; (M.L.G.); (M.B.L.); (D.D.V.); (A.R.T.); (C.L.); (K.H.L.); (K.D.Z.); (P.J.G.)
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN 55905, USA;
- Department of Physiology and Biomedical Engineering, Rochester, MN 55905, USA
| | - Yury P. Gerasimenko
- Pavlov Institute of Physiology of Russian Academy of Sciences, 199034 St. Petersburg, Russia;
- Department of Physiology and Biophysics, University of Louisville, Louisville, KY 40292, USA
| | - Victor R. Edgerton
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, CA 90095, USA;
- Department of Neurobiology, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Neurosurgery, University of California Los Angeles, Los Angeles, CA 90095, USA
- Brain Research Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
- Institut Guttmann, Hospital de Neurorehabilitació, Institut Universitari Adscrit a la Universitat Autònoma de Barcelona, 08916 Badalona, Spain
- Centre for Neuroscience and Regenerative Medicine, Faculty of Science, University of Technology Sydney, Ultimo 2007, Australia
| | - Igor A. Lavrov
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN 55905, USA;
| | - Kristin D. Zhao
- Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, MN 55905, USA; (M.L.G.); (M.B.L.); (D.D.V.); (A.R.T.); (C.L.); (K.H.L.); (K.D.Z.); (P.J.G.)
- Department of Physiology and Biomedical Engineering, Rochester, MN 55905, USA
| | - Peter J. Grahn
- Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, MN 55905, USA; (M.L.G.); (M.B.L.); (D.D.V.); (A.R.T.); (C.L.); (K.H.L.); (K.D.Z.); (P.J.G.)
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN 55905, USA;
| | - Dimitry G. Sayenko
- Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX 77030, USA
- Correspondence: ; Tel.: +1-713-363-7949
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27
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Sasaki A, de Freitas RM, Sayenko DG, Masugi Y, Nomura T, Nakazawa K, Milosevic M. Low-Intensity and Short-Duration Continuous Cervical Transcutaneous Spinal Cord Stimulation Intervention Does Not Prime the Corticospinal and Spinal Reflex Pathways in Able-Bodied Subjects. J Clin Med 2021; 10:jcm10163633. [PMID: 34441927 PMCID: PMC8397025 DOI: 10.3390/jcm10163633] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/29/2021] [Accepted: 08/13/2021] [Indexed: 12/25/2022] Open
Abstract
Cervical transcutaneous spinal cord stimulation (tSCS) has been utilized in applications for improving upper-limb sensory and motor function in patients with spinal cord injury. Although therapeutic effects of continuous cervical tSCS interventions have been reported, neurophysiological mechanisms remain largely unexplored. Specifically, it is not clear whether sub-threshold intensity and 10-min duration continuous cervical tSCS intervention can affect the central nervous system excitability. Therefore, the purpose of this study was to investigate effects of sub-motor-threshold 10-min continuous cervical tSCS applied at rest on the corticospinal and spinal reflex circuit in ten able-bodied individuals. Neurophysiological assessments were conducted to investigate (1) corticospinal excitability via transcranial magnetic stimulation applied on the primary motor cortex to evoke motor-evoked potentials (MEPs) and (2) spinal reflex excitability via single-pulse tSCS applied at the cervical level to evoke posterior root muscle (PRM) reflexes. Measurements were recorded from multiple upper-limb muscles before, during, and after the intervention. Our results showed that low-intensity and short-duration continuous cervical tSCS intervention applied at rest did not significantly affect corticospinal and spinal reflex excitability. The stimulation duration and/or intensity, as well as other stimulating parameters selection, may therefore be critical for inducing neuromodulatory effects during cervical tSCS.
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Affiliation(s)
- Atsushi Sasaki
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan; (A.S.); (Y.M.); (K.N.)
- Japan Society for the Promotion of Science, Tokyo 102-0083, Japan
| | - Roberto M. de Freitas
- Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, Osaka 560-8531, Japan; (R.M.d.F.); (T.N.)
| | - Dimitry G. Sayenko
- Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX 77030, USA;
| | - Yohei Masugi
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan; (A.S.); (Y.M.); (K.N.)
- School of Health Sciences, Tokyo International University, Saitama 350-1197, Japan
| | - Taishin Nomura
- Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, Osaka 560-8531, Japan; (R.M.d.F.); (T.N.)
| | - Kimitaka Nakazawa
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan; (A.S.); (Y.M.); (K.N.)
| | - Matija Milosevic
- Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, Osaka 560-8531, Japan; (R.M.d.F.); (T.N.)
- Correspondence:
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28
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Ibáñez J, Angeli CA, Harkema SJ, Farina D, Rejc E. Recruitment order of motor neurons promoted by epidural stimulation in individuals with spinal cord injury. J Appl Physiol (1985) 2021; 131:1100-1110. [PMID: 34382840 PMCID: PMC8461808 DOI: 10.1152/japplphysiol.00293.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Spinal cord epidural stimulation (scES) combined with activity-based training can promote motor function recovery in individuals with motor complete spinal cord injury (SCI). The characteristics of motor neuron recruitment, which influence different aspects of motor control, are still unknown when motor function is promoted by scES. Here, we enrolled five individuals with chronic motor complete SCI implanted with a scES unit to study the recruitment order of motor neurons during standing enabled by scES. We recorded high-density electromyography (HD-EMG) signals on the vastus lateralis muscle, and inferred the order of recruitment of motor neurons from the relation between amplitude and conduction velocity of the scES-evoked EMG responses along the muscle fibers. Conduction velocity of scES-evoked responses was modulated over time, while stimulation parameters and standing condition remained constant, with average values ranging between 3.0±0.1 and 4.4±0.3 m/s. We found that the human spinal circuitry receiving epidural stimulation can promote both orderly (according to motor neuron size) and inverse trends of motor neuron recruitment, and that the engagement of spinal networks promoting rhythmic activity may favor orderly recruitment trends. Conversely, the different recruitment trends did not appear to be related with time since injury or scES implant, nor to the ability to achieve independent knees extension, nor to the conduction velocity values. The proposed approach can be implemented to investigate the effects of stimulation parameters and training-induced neural plasticity on the characteristics of motor neuron recruitment order, contributing to improve mechanistic understanding and effectiveness of epidural stimulation-promoted motor recovery after SCI.
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Affiliation(s)
- Jaime Ibáñez
- Department of Bioengineering, Imperial College London, London, United Kingdom.,Department of Clinical and Movement Disorders, Institute of Neurology, University College London, London, United Kingdom
| | - Claudia A Angeli
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, United States.,Department of Bioengineering, University of Louisville, Louisville, Kentucky, United States.,Frazier Rehabilitation Institute, University of Louisville Health, Louisville, Kentucky, United States
| | - Susan J Harkema
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, United States.,Department of Bioengineering, University of Louisville, Louisville, Kentucky, United States.,Frazier Rehabilitation Institute, University of Louisville Health, Louisville, Kentucky, United States.,Department of Neurological Surgery, University of Louisville, Louisville, Kentucky, United States
| | - Dario Farina
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Enrico Rejc
- Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky, United States.,Department of Neurological Surgery, University of Louisville, Louisville, Kentucky, United States
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29
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Bogacheva IN, Shcherbakova NA, Savokhin AA, Grishin AA, Gerasimenko YP. Phase-Dependent Effects of Transcutaneous Spinal Cord Stimulation on Regulation of Kinematics of Human Stepping Motions. Biophysics (Nagoya-shi) 2021. [DOI: 10.1134/s0006350921040035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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30
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Sharma P, Shah PK. In vivo electrophysiological mechanisms underlying cervical epidural stimulation in adult rats. J Physiol 2021; 599:3121-3150. [PMID: 33894695 DOI: 10.1113/jp281146] [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] [Received: 11/23/2020] [Accepted: 03/15/2021] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS To electrophysiologically determine the predominant neural structures activated with cervical epidural stimulation (ES), well-established electrophysiological protocols (single-pulse, paired-pulse and multiple frequency stimulation) were delivered at rest, during motor activity and under anaesthesia in adult rats. Cervical ES resulted in spinal evoked motor responses with three different waveforms - early response (ER), middle response (MR) and late response (LR). ERs remained unmodulated by repeated stimulation protocols. In contrast, MRs and LRs were modulated by repeated stimulation protocols and volitional motor activity. ERs are consequential to the direct activation of motor efferents; MRs are secondary to type-I sensory afferent activation and LRs result from the engagement of wider spinal interneuronal circuitry with potential influence from supraspinal pathways. Evidence from this work is fundamental in enhancing our understanding of cervical ES, and critical in refining the design of neuromodulation-based rehabilitative strategies and in the construction of neuroprosthetics. ABSTRACT Epidural stimulation (ES) of the lumbar spinal cord has demonstrated significant improvements in various physiological functions after a traumatic spinal cord injury in humans. Electrophysiological evidence from rodent, human and computational studies collectively suggest that the functional recovery following lumbar ES is mediated via direct activation of sensory afferent fibres. However, the mechanisms underlying cervical ES have not been comprehensively studied, which greatly limits our understanding of its effectiveness in restoring upper limb function. In this work, we determined the predominant neural structures that are activated with cervical ES using in vivo cervical spinal evoked motor responses (SEMRs). Standard electrophysiological protocols (single-pulse, paired-pulse and multiple frequency stimulation) were implemented in 11 awake and anaesthetized rats in four experimental stages. Three distinct types of cervical SEMRs were identified based on latency of their appearance: early response (ER), middle response (MR) and late response (LR). ERs remained unmodulated by repeated stimulation protocols. MRs and LRs were modulated by repeated stimulation protocols and volitional motor activity. Except for LRs being completely abolished under urethane, ketamine or urethane anaesthesia did not affect the appearance of cervical SEMRs. Our data, backed by literature, suggest that ERs are secondary to the direct activation of motor efferents, MRs are elicited by activation of type-I sensory afferents and LRs result from the engagement of interneuronal circuitry with potential influence from supraspinal pathways. The gathered information paves the way to designing motor rehabilitation strategies that can utilize cervical ES to recover upper limb function following neurological deficits.
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Affiliation(s)
- Pawan Sharma
- Division of Rehabilitation Sciences, Department of Physical Therapy, School of Health Technology and Management, Stony Brook University, Stony Brook, NY, 11727, USA
| | - Prithvi K Shah
- Division of Rehabilitation Sciences, Department of Physical Therapy, School of Health Technology and Management, Stony Brook University, Stony Brook, NY, 11727, USA
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31
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Bogacheva IN, Shcherbakova NA, Grishin AA, Gerasimenko YP. Effects of Phase Shifts of Transcutaneous
Electrical Spinal Cord Stimulation on the Kinematic Characteristics
of Stepping Movements in Humans. J EVOL BIOCHEM PHYS+ 2021. [DOI: 10.1134/s0022093021020137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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32
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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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Lalonde NR, Bui TV. Do spinal circuits still require gating of sensory information by presynaptic inhibition after spinal cord injury? CURRENT OPINION IN PHYSIOLOGY 2021. [DOI: 10.1016/j.cophys.2020.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Hofstoetter US, Danner SM, Freundl B, Binder H, Lackner P, Minassian K. Ipsi- and Contralateral Oligo- and Polysynaptic Reflexes in Humans Revealed by Low-Frequency Epidural Electrical Stimulation of the Lumbar Spinal Cord. Brain Sci 2021; 11:brainsci11010112. [PMID: 33467053 PMCID: PMC7830402 DOI: 10.3390/brainsci11010112] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/11/2021] [Accepted: 01/12/2021] [Indexed: 01/16/2023] Open
Abstract
Epidural electrical stimulation (EES) applied over the human lumbosacral spinal cord provides access to afferent fibers from virtually all lower-extremity nerves. These afferents connect to spinal networks that play a pivotal role in the control of locomotion. Studying EES-evoked responses mediated through these networks can identify some of their functional components. We here analyzed electromyographic (EMG) responses evoked by low-frequency (2–6 Hz) EES derived from eight individuals with chronic, motor complete spinal cord injury. We identified and separately analyzed three previously undescribed response types: first, crossed reflexes with onset latencies of ~55 ms evoked in the hamstrings; second, oligosynaptic reflexes within 50 ms post-stimulus superimposed on the monosynaptic posterior root-muscle reflexes in the flexor muscle tibialis anterior, but with higher thresholds and no rate-sensitive depression; third, polysynaptic responses with variable EMG shapes within 50–450 ms post-stimulus evoked in the tibialis anterior and triceps surae, some of which demonstrated consistent changes in latencies with graded EES. Our observations suggest the activation of commissural neurons, lumbar propriospinal interneurons, and components of the late flexion reflex circuits through group I and II proprioceptive afferent inputs. These potential neural underpinnings have all been related to spinal locomotion in experimental studies.
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Affiliation(s)
- Ursula S. Hofstoetter
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 1090 Vienna, Austria;
| | - Simon M. Danner
- Department of Neurobiology and Anatomy, College of Medicine, Drexel University, Philadelphia, PA 19129, USA;
| | - Brigitta Freundl
- Neurological Center, Klinik Penzing—Wiener Gesundheitsverbund, 1140 Vienna, Austria; (B.F.); (H.B.); (P.L.)
| | - Heinrich Binder
- Neurological Center, Klinik Penzing—Wiener Gesundheitsverbund, 1140 Vienna, Austria; (B.F.); (H.B.); (P.L.)
| | - Peter Lackner
- Neurological Center, Klinik Penzing—Wiener Gesundheitsverbund, 1140 Vienna, Austria; (B.F.); (H.B.); (P.L.)
| | - Karen Minassian
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 1090 Vienna, Austria;
- Correspondence:
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Meyer C, Hofstoetter US, Hubli M, Hassani RH, Rinaldo C, Curt A, Bolliger M. Immediate Effects of Transcutaneous Spinal Cord Stimulation on Motor Function in Chronic, Sensorimotor Incomplete Spinal Cord Injury. J Clin Med 2020; 9:E3541. [PMID: 33147884 PMCID: PMC7694146 DOI: 10.3390/jcm9113541] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 10/22/2020] [Accepted: 10/30/2020] [Indexed: 12/15/2022] Open
Abstract
Deficient ankle control after incomplete spinal cord injury (iSCI) often accentuates walking impairments. Transcutaneous electrical spinal cord stimulation (tSCS) has been shown to augment locomotor activity after iSCI, presumably due to modulation of spinal excitability. However, the effects of possible excitability modulations induced by tSCS on ankle control have not yet been assessed. This study investigated the immediate (i.e., without training) effects during single-sessions of tonic tSCS on ankle control, spinal excitability, and locomotion in ten individuals with chronic, sensorimotor iSCI (American Spinal Injury Association Impairment Scale D). Participants performed rhythmic ankle movements (dorsi- and plantar flexion) at a given rate, and irregular ankle movements following a predetermined trajectory with and without tonic tSCS at 15 Hz, 30 Hz, and 50 Hz. In a subgroup of eight participants, the effects of tSCS on assisted over-ground walking were studied. Furthermore, the activity of a polysynaptic spinal reflex, associated with spinal locomotor networks, was investigated to study the effect of the stimulation on the dedicated spinal circuitry associated with locomotor function. Tonic tSCS at 30 Hz immediately improved maximum dorsiflexion by +4.6° ± 0.9° in the more affected lower limb during the rhythmic ankle movement task, resulting in an increase of +2.9° ± 0.9° in active range of motion. Coordination of ankle movements, assessed by the ability to perform rhythmic ankle movements at a given target rate and to perform irregular movements according to a trajectory, was unchanged during stimulation. tSCS at 30 Hz modulated spinal reflex activity, reflected by a significant suppression of pathological activity specific to SCI in the assessed polysynaptic spinal reflex. During walking, there was no statistical group effect of tSCS. In the subgroup of eight assessed participants, the three with the lowest as well as the one with the highest walking function scores showed positive stimulation effects, including increased maximum walking speed, or more continuous and faster stepping at a self-selected speed. Future studies need to investigate if multiple applications and individual optimization of the stimulation parameters can increase the effects of tSCS, and if the technique can improve the outcome of locomotor rehabilitation after iSCI.
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Affiliation(s)
- Christian Meyer
- Spinal Cord Injury Center, Balgrist University Hospital, Forchstrasse 340, 8008 Zurich, Switzerland; (C.M.); (M.H.); (R.H.H.); (C.R.); (A.C.); (M.B.)
| | - Ursula S. Hofstoetter
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, 1090 Vienna, Austria
| | - Michèle Hubli
- Spinal Cord Injury Center, Balgrist University Hospital, Forchstrasse 340, 8008 Zurich, Switzerland; (C.M.); (M.H.); (R.H.H.); (C.R.); (A.C.); (M.B.)
| | - Roushanak H. Hassani
- Spinal Cord Injury Center, Balgrist University Hospital, Forchstrasse 340, 8008 Zurich, Switzerland; (C.M.); (M.H.); (R.H.H.); (C.R.); (A.C.); (M.B.)
| | - Carmen Rinaldo
- Spinal Cord Injury Center, Balgrist University Hospital, Forchstrasse 340, 8008 Zurich, Switzerland; (C.M.); (M.H.); (R.H.H.); (C.R.); (A.C.); (M.B.)
| | - Armin Curt
- Spinal Cord Injury Center, Balgrist University Hospital, Forchstrasse 340, 8008 Zurich, Switzerland; (C.M.); (M.H.); (R.H.H.); (C.R.); (A.C.); (M.B.)
| | - Marc Bolliger
- Spinal Cord Injury Center, Balgrist University Hospital, Forchstrasse 340, 8008 Zurich, Switzerland; (C.M.); (M.H.); (R.H.H.); (C.R.); (A.C.); (M.B.)
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Megía-García Á, Serrano-Muñoz D, Taylor J, Avendaño-Coy J, Comino-Suárez N, Gómez-Soriano J. Transcutaneous Spinal Cord Stimulation Enhances Quadriceps Motor Evoked Potential in Healthy Participants: A Double-Blind Randomized Controlled Study. J Clin Med 2020; 9:jcm9103275. [PMID: 33066103 PMCID: PMC7601803 DOI: 10.3390/jcm9103275] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 09/28/2020] [Accepted: 10/12/2020] [Indexed: 12/29/2022] Open
Abstract
Transcutaneous electrical spinal cord stimulation (tSCS) is a non-invasive technique for neuromodulation and has therapeutic potential for motor rehabilitation following spinal cord injury. The main aim of the present study is to quantify the effect of a single session of tSCS on lower limb motor evoked potentials (MEPs) in healthy participants. A double-blind, sham-controlled, randomized, crossover, clinical trial was carried out in 15 participants. Two 10-min sessions of tSCS (active-tSCS and sham-tSCS) were applied at the T11-T12 vertebral level. Quadriceps (Q) and tibialis anterior (TA) muscle MEPs were recorded at baseline, during and after tSCS. Q and TA isometric maximal voluntary contraction was also recorded. A significant increase of the Q-MEP amplitude was observed during active-tSCS (1.96 ± 0.3 mV) when compared from baseline (1.40 ± 0.2 mV; p = 0.01) and when compared to sham-tSCS at the same time-point (1.13 ± 0.3 mV; p = 0.03). No significant modulation was identified for TA-MEP amplitude or for Q and TA isometric maximal voluntary isometric strength. In conclusion, tSCS applied over the T11-T12 vertebral level increased Q-MEP but not TA-MEP compared to sham stimulation. The specific neuromodulatory effect of tSCS on Q-MEP may reflect optimal excitation of this motor response at the interneuronal or motoneuronal level.
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Affiliation(s)
- Álvaro Megía-García
- Biomechanical and Technical Aids Unit, National Hospital for Paraplegia, SESCAM, 45071 Toledo, Spain;
- Toledo Physiotherapy Research Group (GIFTO), Faculty of Physiotherapy and Nursing, Castilla La Mancha University, 45071 Toledo, Spain; (J.A.-C.); (N.C.-S.); (J.G.-S.)
| | - Diego Serrano-Muñoz
- Toledo Physiotherapy Research Group (GIFTO), Faculty of Physiotherapy and Nursing, Castilla La Mancha University, 45071 Toledo, Spain; (J.A.-C.); (N.C.-S.); (J.G.-S.)
- Correspondence: ; Tel.: +34-925268800 (ext. 5830)
| | - Julian Taylor
- Sensorimotor Function Group, National Hospital for Paraplegia, SESCAM, 45071 Toledo, Spain;
- Harris Manchester College, University of Oxford, Oxford OX1 3TD, UK
| | - Juan Avendaño-Coy
- Toledo Physiotherapy Research Group (GIFTO), Faculty of Physiotherapy and Nursing, Castilla La Mancha University, 45071 Toledo, Spain; (J.A.-C.); (N.C.-S.); (J.G.-S.)
| | - Natalia Comino-Suárez
- Toledo Physiotherapy Research Group (GIFTO), Faculty of Physiotherapy and Nursing, Castilla La Mancha University, 45071 Toledo, Spain; (J.A.-C.); (N.C.-S.); (J.G.-S.)
- Neural Rehabilitation Group, Cajal Institute, Spanish National Research Council (CSIC), 28002 Madrid, Spain
| | - Julio Gómez-Soriano
- Toledo Physiotherapy Research Group (GIFTO), Faculty of Physiotherapy and Nursing, Castilla La Mancha University, 45071 Toledo, Spain; (J.A.-C.); (N.C.-S.); (J.G.-S.)
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Hou J, Nelson R, Mohammad N, Mustafa G, Plant D, Thompson FJ, Bose P. Effect of Simultaneous Combined Treadmill Training and Magnetic Stimulation on Spasticity and Gait Impairments after Cervical Spinal Cord Injury. J Neurotrauma 2020; 37:1999-2013. [DOI: 10.1089/neu.2019.6961] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Affiliation(s)
- Jiamei Hou
- Department of Physiological Sciences, University of Florida, Gainesville, Florida, USA
- BRRC, North Florida/South Georgia Veterans Health System, Gainesville, Florida, USA
| | - Rachel Nelson
- BRRC, North Florida/South Georgia Veterans Health System, Gainesville, Florida, USA
| | - Naweed Mohammad
- BRRC, North Florida/South Georgia Veterans Health System, Gainesville, Florida, USA
| | - Golam Mustafa
- Department of Physiological Sciences, University of Florida, Gainesville, Florida, USA
- BRRC, North Florida/South Georgia Veterans Health System, Gainesville, Florida, USA
| | - Daniel Plant
- Research Service, North Florida/South Georgia Veterans Health System, Gainesville, Florida, USA
| | - Floyd J. Thompson
- Department of Physiological Sciences, University of Florida, Gainesville, Florida, USA
- BRRC, North Florida/South Georgia Veterans Health System, Gainesville, Florida, USA
- Department of Neuroscience, University of Florida, Gainesville, Florida, USA
| | - Prodip Bose
- Department of Physiological Sciences, University of Florida, Gainesville, Florida, USA
- BRRC, North Florida/South Georgia Veterans Health System, Gainesville, Florida, USA
- Department of Anesthesiology, University of Florida, Gainesville, Florida, USA
- Department of Neurology, University of Florida, Gainesville, Florida, USA
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Sasaki A, Kaneko N, Masugi Y, Milosevic M, Nakazawa K. Interlimb neural interactions in corticospinal and spinal reflex circuits during preparation and execution of isometric elbow flexion. J Neurophysiol 2020; 124:652-667. [DOI: 10.1152/jn.00705.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
We found that upper limb muscle contractions facilitated corticospinal circuits controlling lower limb muscles even during motor preparation, whereas motor execution of the task was required to facilitate spinal circuits. We also found that facilitation did not depend on whether contralateral or ipsilateral hands were contracted or if they were contracted bilaterally. Overall, these findings suggest that training of unaffected upper limbs may be useful to enhance facilitation of affected lower limbs in paraplegic individuals.
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Affiliation(s)
- Atsushi Sasaki
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Tokyo, Japan
- Japan Society for the Promotion of Science, Chiyoda, Tokyo, Japan
| | - Naotsugu Kaneko
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Tokyo, Japan
- Japan Society for the Promotion of Science, Chiyoda, Tokyo, Japan
| | - Yohei Masugi
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Tokyo, Japan
- Institute of Sports Medicine and Science, Tokyo International University, Kawagoe, Saitama, Japan
| | - Matija Milosevic
- Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan
| | - Kimitaka Nakazawa
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Tokyo, Japan
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Al’joboori Y, Massey SJ, Knight SL, Donaldson NDN, Duffell LD. The Effects of Adding Transcutaneous Spinal Cord Stimulation (tSCS) to Sit-To-Stand Training in People with Spinal Cord Injury: A Pilot Study. J Clin Med 2020; 9:jcm9092765. [PMID: 32858977 PMCID: PMC7565331 DOI: 10.3390/jcm9092765] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/19/2020] [Accepted: 08/21/2020] [Indexed: 02/08/2023] Open
Abstract
Spinal cord stimulation may enable recovery of volitional motor control in people with chronic Spinal Cord Injury (SCI). In this study we explored the effects of adding SCS, applied transcutaneously (tSCS) at vertebral levels T10/11, to a sit-to-stand training intervention in people with motor complete and incomplete SCI. Nine people with chronic SCI (six motor complete; three motor incomplete) participated in an 8-week intervention, incorporating three training sessions per week. Participants received either tSCS combined with sit-to-stand training (STIM) or sit-to-stand training alone (NON-STIM). Outcome measures were carried out before and after the intervention. Seven participants completed the intervention (STIM N = 5; NON-STIM N = 2). Post training, improvements in International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) motor scores were noted in three STIM participants (range 1.0–7.0), with no change in NON-STIM participants. Recovery of volitional lower limb muscle activity and/or movement (with tSCS off) was noted in three STIM participants. Unassisted standing was not achieved in any participant, although standing with minimal assistance was achieved in one STIM participant. This pilot study has shown that the recruitment of participants, intervention and outcome measures were all feasible in this study design. However, some modifications are recommended for a larger trial.
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Affiliation(s)
- Yazi Al’joboori
- Department of Medical Physics & Biomedical Engineering, UCL, London WC1E 6BT, UK; (N.d.N.D.); (L.D.D.)
- Aspire CREATe, UCL, Stanmore HA7 4LP, UK;
- Correspondence: ; Tel.: +44-020-3108-4083
| | | | - Sarah L. Knight
- London Spinal Cord Injury Centre, Royal National Orthopaedic Hospital, Stanmore HA7 4LP, UK;
| | - Nick de N. Donaldson
- Department of Medical Physics & Biomedical Engineering, UCL, London WC1E 6BT, UK; (N.d.N.D.); (L.D.D.)
| | - Lynsey D. Duffell
- Department of Medical Physics & Biomedical Engineering, UCL, London WC1E 6BT, UK; (N.d.N.D.); (L.D.D.)
- Aspire CREATe, UCL, Stanmore HA7 4LP, UK;
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Taccola G, Salazar BH, Apicella R, Hogan MK, Horner PJ, Sayenko D. Selective Antagonism of A1 Adenosinergic Receptors Strengthens the Neuromodulation of the Sensorimotor Network During Epidural Spinal Stimulation. Front Syst Neurosci 2020; 14:44. [PMID: 32760254 PMCID: PMC7372902 DOI: 10.3389/fnsys.2020.00044] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 06/16/2020] [Indexed: 01/02/2023] Open
Abstract
Although epidural spinal stimulation (ESS) results in promising therapeutic effects in individuals with spinal cord injury (SCI), its potential to generate functional motor recovery varies between individuals and remains largely unclear. However, both preclinical and clinical studies indicate the capacity of electrical and pharmacological interventions to synergistically increase the engagement of spinal sensorimotor networks and regain motor function after SCI. This study explored whether selective pharmacological antagonism of the adenosine A1 receptor subtype synergizes with ESS, thereby increasing motor response. We hypothesized that selective pharmacological antagonism of A1 receptors during ESS would produce facilitatory effects in spinal sensorimotor networks detected as an increased amplitude of spinally-evoked motor potentials and sustained duration of ESS induced activity. Terminal experiments were performed in adult rats using trains of stereotyped pulses at 40 Hz delivered at L5 with the local administration to the cord of 8-cyclopentyl-1,3-dipropylxanthine (DPCPX). We demonstrated that ESS combined with the blockage of A1 receptors increased the magnitude of the endogenous modulation and postponed the decay of responses that occur during ESS alone. Although DPCPX significantly increased the yield of repetitive stimulation in intact spinal cords, the effects of A1 antagonism on motor evoked responses after an acute spinal transection was not detected. These studies support the future investigation of the optimal dosage, methods of delivery, and systemic effects of the synergistic application of A1 antagonists and spinal stimulation in the intact and injured spinal cord.
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Affiliation(s)
- Giuliano Taccola
- Department of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX, United States
| | - Betsy Habeth Salazar
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX, United States
| | - Rosamaria Apicella
- Department of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy
| | - Matthew Kevin Hogan
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX, United States
| | - Philip John Horner
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX, United States
| | - Dimitry Sayenko
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX, United States
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Duffell LD, Donaldson NDN. A Comparison of FES and SCS for Neuroplastic Recovery After SCI: Historical Perspectives and Future Directions. Front Neurol 2020; 11:607. [PMID: 32714270 PMCID: PMC7344227 DOI: 10.3389/fneur.2020.00607] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 05/25/2020] [Indexed: 12/17/2022] Open
Abstract
There is increasing evidence that neuroplastic changes can occur even years after spinal cord injury, leading to reduced disability and better health which should reduce the cost of healthcare. In motor-incomplete spinal cord injury, recovery of leg function may occur if repetitive training causes afferent input to the lumbar spinal cord. The afferent input may be due to activity-based therapy without electrical stimulation but we present evidence that it is faster with electrical stimulation. This may be spinal cord stimulation or peripheral nerve stimulation. Recovery is faster if the stimulation is phasic and that the patient is trying to use their legs during the training. All the published studies are small, so all conclusions are provisional, but it appears that patients with more disability (AIS A and B) may need to continue using stimulation and for them, an implanted stimulator is likely to be convenient. Patients with less disability (AIS C and D) may make useful recovery and improve their quality of life from a course of therapy. This might be locomotion therapy but we argue that cycling with electrical stimulation, which uses biofeedback to encourage descending drive, causes rapid recovery and might be used with little supervision at home, making it much less expensive. Such an electrical therapy followed by conventional physiotherapy might be affordable for the many people living with chronic SCI. To put this in perspective, we present some information about what treatments are funded in the UK and the US.
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Affiliation(s)
- Lynsey D Duffell
- Implanted Devices Group, University College London, London, United Kingdom.,Aspire CREATe, University College London, London, United Kingdom
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