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Yildiz N, Cecen S, Sancar N, Karacan I, Knikou M, Türker KS. Postsynaptic potentials of soleus motor neurons produced by transspinal stimulation: a human single-motor unit study. J Neurophysiol 2024; 131:1101-1111. [PMID: 38656134 DOI: 10.1152/jn.00077.2024] [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: 02/22/2024] [Revised: 04/16/2024] [Accepted: 04/17/2024] [Indexed: 04/26/2024] Open
Abstract
Transspinal (or transcutaneous spinal cord) stimulation is a noninvasive, cost-effective, easily applied method with great potential as a therapeutic modality for recovering somatic and nonsomatic functions in upper motor neuron disorders. However, how transspinal stimulation affects motor neuron depolarization is poorly understood, limiting the development of effective transspinal stimulation protocols for rehabilitation. In this study, we characterized the responses of soleus α motor neurons to single-pulse transspinal stimulation using single-motor unit (SMU) discharges as a proxy given the 1:1 discharge activation between the motor neuron and the motor unit. Peristimulus time histogram, peristimulus frequencygram, and surface electromyography (sEMG) were used to characterize the postsynaptic potentials of soleus motor neurons. Transspinal stimulation produced short-latency excitatory postsynaptic potentials (EPSPs) followed by two distinct phases of inhibitory postsynaptic potentials (IPSPs) in most soleus motor neurons and only IPSPs in others. Transspinal stimulation generated double discharges at short interspike intervals in a few motor units. The short-latency EPSPs were likely mediated by muscle spindle group Ia and II afferents, and the IPSPs via excitation of group Ib afferents and recurrent collaterals of motor neurons leading to activation of diverse spinal inhibitory interneuronal circuits. Further studies are warranted to understand better how transspinal stimulation affects depolarization of α motor neurons over multiple spinal segments. This knowledge will be seminal for developing effective transspinal stimulation protocols in upper motor neuron lesions.NEW & NOTEWORTHY Transspinal stimulation produces distinct actions on soleus motor neurons: an early short-latency excitation followed by two inhibitions or only inhibition and doublets. These results show how transspinal stimulation affects depolarization of soleus α motor neurons in healthy humans.
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Affiliation(s)
- Nilgün Yildiz
- Faculty of Dentistry & Physiology, Istanbul Gelisim University, Istanbul, Türkiye
- Department of Physiotherapy and Rehabilitation, Faculty of Health Sciences, Istanbul Gelisim University, Istanbul, Türkiye
| | - Serpil Cecen
- Department of Physiology, Hamidiye Medical School, Health Science University, Istanbul, Türkiye
| | - Nuray Sancar
- Faculty of Dentistry & Physiology, Istanbul Gelisim University, Istanbul, Türkiye
| | - Ilhan Karacan
- Hamidiye Medical School, Physical Therapy Research and Education Hospital, Health Science University, Istanbul, Türkiye
| | - Maria Knikou
- Klab4Recovery Research Program, The City University of New York, New York, New York, United States
- Department of Physical Therapy, College of Staten Island, The City University of New York, New York, New York, United States
- PhD Program in Biology and Collaborative Neuroscience Program, Graduate Center of The City University of New York and College of Staten Island, New York, New York, United States
| | - Kemal S Türker
- Faculty of Dentistry & Physiology, Istanbul Gelisim University, Istanbul, Türkiye
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Sayed Ahmad AM, Raphael M, Han JF, Ahmed Y, Moustafa M, Solomon SK, Skiadopoulos A, Knikou M. Soleus H-reflex amplitude modulation during walking remains physiological during transspinal stimulation in humans. Exp Brain Res 2024; 242:1267-1276. [PMID: 38366214 DOI: 10.1007/s00221-024-06779-x] [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: 11/06/2023] [Accepted: 01/08/2024] [Indexed: 02/18/2024]
Abstract
The soleus H-reflex modulation pattern was investigated during stepping following transspinal stimulation over the thoracolumbar region at 15, 30, and 50 Hz with 10 kHz carry-over frequency above and below the paresthesia threshold. The soleus H-reflex was elicited by posterior tibial nerve stimulation with a single 1 ms pulse at an intensity that the M-wave amplitudes ranged from 0 to 15% of the maximal M-wave evoked 80 ms after the test stimulus, and the soleus H-reflex was half the size of the maximal H-reflex evoked on the ascending portion of the recruitment curve. During treadmill walking, the soleus H-reflex was elicited every 2 or 3 steps, and stimuli were randomly dispersed across the step cycle which was divided in 16 equal bins. For each subject and condition, the soleus M-wave and H-reflex were normalized to the maximal M-wave. The soleus background electromyographic (EMG) activity was estimated as the linear envelope for 50 ms duration starting at 100 ms before posterior tibial nerve stimulation for each bin. The gain was determined as the slope of the relationship between the soleus H-reflex and the soleus background EMG activity. The soleus H-reflex phase-dependent amplitude modulation remained unaltered during transspinal stimulation, regardless frequency, or intensity. Similarly, the H-reflex slope and intercept remained the same for all transspinal stimulation conditions tested. Locomotor EMG activity was increased in knee extensor muscles during transspinal stimulation at 30 and 50 Hz throughout the step cycle while no effects were observed in flexor muscles. These findings suggest that transspinal stimulation above and below the paresthesia threshold at 15, 30, and 50 Hz does not block or impair spinal integration of proprioceptive inputs and increases activity of thigh muscles that affect both hip and knee joint movement. Transspinal stimulation may serve as a neurorecovery strategy to augment standing or walking ability in upper motoneuron lesions.
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Affiliation(s)
- Abdullah M Sayed Ahmad
- Klab4Recovery Research Program, The City University of New York, New York, NY, USA
- Department of Physical Therapy, College of Staten Island, The City University of New York, Staten Island, NY, USA
| | - Meghan Raphael
- Department of Physical Therapy, College of Staten Island, The City University of New York, Staten Island, NY, USA
| | - Jessy Feng Han
- Department of Physical Therapy, College of Staten Island, The City University of New York, Staten Island, NY, USA
| | - Yoseph Ahmed
- Department of Physical Therapy, College of Staten Island, The City University of New York, Staten Island, NY, USA
| | - Mohamed Moustafa
- Department of Physical Therapy, College of Staten Island, The City University of New York, Staten Island, NY, USA
| | - Shammah K Solomon
- Klab4Recovery Research Program, The City University of New York, New York, NY, USA
- Department of Physical Therapy, College of Staten Island, The City University of New York, Staten Island, NY, USA
| | - Andreas Skiadopoulos
- Klab4Recovery Research Program, The City University of New York, New York, NY, USA
- Department of Physical Therapy, College of Staten Island, The City University of New York, Staten Island, NY, USA
| | - Maria Knikou
- Klab4Recovery Research Program, The City University of New York, New York, NY, USA.
- Department of Physical Therapy, College of Staten Island, The City University of New York, Staten Island, NY, USA.
- PhD Program in Biology and Collaborative Neuroscience Program, DPT Department, Graduate Center of The City University of New York and College of Staten Island, Staten Island, NY, USA.
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Kumru H, Ros-Alsina A, García Alén L, Vidal J, Gerasimenko Y, Hernandez A, Wrigth M. Improvement in Motor and Walking Capacity during Multisegmental Transcutaneous Spinal Stimulation in Individuals with Incomplete Spinal Cord Injury. Int J Mol Sci 2024; 25:4480. [PMID: 38674065 PMCID: PMC11050444 DOI: 10.3390/ijms25084480] [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: 03/28/2024] [Revised: 04/12/2024] [Accepted: 04/12/2024] [Indexed: 04/28/2024] Open
Abstract
Transcutaneous multisegmental spinal cord stimulation (tSCS) has shown superior efficacy in modulating spinal locomotor circuits compared to single-site stimulation in individuals with spinal cord injury (SCI). Building on these findings, we hypothesized that administering a single session of tSCS at multiple spinal segments may yield greater enhancements in muscle strength and gait function during stimulation compared to tSCS at only one or two segments. In our study, tSCS was applied at single segments (C5, L1, and Coc1), two segments (C5-L1, C5-Coc1, and L1-Coc1), or multisegments (C5-L1-Coc1) in a randomized order. We evaluated the 6-m walking test (6MWT) and maximum voluntary contraction (MVC) and assessed the Hmax/Mmax ratio during stimulation in ten individuals with incomplete motor SCI. Our findings indicate that multisegmental tSCS improved walking time and reduced spinal cord excitability, as measured by the Hmax/Mmax ratio, similar to some single or two-site tSCS interventions. However, only multisegmental tSCS resulted in increased tibialis anterior (TA) muscle strength. These results suggest that multisegmental tSCS holds promise for enhancing walking capacity, increasing muscle strength, and altering spinal cord excitability in individuals with incomplete SCI.
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Affiliation(s)
- Hatice Kumru
- Fundación Institut Guttmann, Institut Universitari de NeurorehabilitacióAdscrit a la UAB, 08916 Badalona, Spain; (A.R.-A.); (L.G.A.); (J.V.); (A.H.); (M.W.)
- Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
- Fundació Institut d’Investigació en Ciències de la Salut Germans Trias i Pujol, 08916 Badalona, Spain
| | - Aina Ros-Alsina
- Fundación Institut Guttmann, Institut Universitari de NeurorehabilitacióAdscrit a la UAB, 08916 Badalona, Spain; (A.R.-A.); (L.G.A.); (J.V.); (A.H.); (M.W.)
| | - Loreto García Alén
- Fundación Institut Guttmann, Institut Universitari de NeurorehabilitacióAdscrit a la UAB, 08916 Badalona, Spain; (A.R.-A.); (L.G.A.); (J.V.); (A.H.); (M.W.)
- Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
| | - Joan Vidal
- Fundación Institut Guttmann, Institut Universitari de NeurorehabilitacióAdscrit a la UAB, 08916 Badalona, Spain; (A.R.-A.); (L.G.A.); (J.V.); (A.H.); (M.W.)
- Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
- Fundació Institut d’Investigació en Ciències de la Salut Germans Trias i Pujol, 08916 Badalona, Spain
| | - Yury Gerasimenko
- Pavlov Institute of Physiology, St. Petersburg 199034, Russia;
- Department of Physiology and Biophysics, University of Louisville, Louisville, KY 40292, USA
| | - Agusti Hernandez
- Fundación Institut Guttmann, Institut Universitari de NeurorehabilitacióAdscrit a la UAB, 08916 Badalona, Spain; (A.R.-A.); (L.G.A.); (J.V.); (A.H.); (M.W.)
- Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
| | - Mark Wrigth
- Fundación Institut Guttmann, Institut Universitari de NeurorehabilitacióAdscrit a la UAB, 08916 Badalona, Spain; (A.R.-A.); (L.G.A.); (J.V.); (A.H.); (M.W.)
- Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
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Tajali S, Balbinot G, Pakosh M, Sayenko DG, Zariffa J, Masani K. Modulations in neural pathways excitability post transcutaneous spinal cord stimulation among individuals with spinal cord injury: a systematic review. Front Neurosci 2024; 18:1372222. [PMID: 38591069 PMCID: PMC11000807 DOI: 10.3389/fnins.2024.1372222] [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: 01/17/2024] [Accepted: 03/06/2024] [Indexed: 04/10/2024] Open
Abstract
Introduction Transcutaneous spinal cord stimulation (TSCS), a non-invasive form of spinal cord stimulation, has been shown to improve motor function in individuals living with spinal cord injury (SCI). However, the effects of different types of TSCS currents including direct current (DC-TSCS), alternating current (AC-TSCS), and spinal paired stimulation on the excitability of neural pathways have not been systematically investigated. The objective of this systematic review was to determine the effects of TSCS on the excitability of neural pathways in adults with non-progressive SCI at any level. Methods The following databases were searched from their inception until June 2022: MEDLINE ALL, Embase, Web of Science, Cochrane Library, and clinical trials. A total of 4,431 abstracts were screened, and 23 articles were included. Results Nineteen studies used TSCS at the thoracolumbar enlargement for lower limb rehabilitation (gait & balance) and four studies used cervical TSCS for upper limb rehabilitation. Sixteen studies measured spinal excitability by reporting different outcomes including Hoffmann reflex (H-reflex), flexion reflex excitability, spinal motor evoked potentials (SMEPs), cervicomedullay evoked potentials (CMEPs), and cutaneous-input-evoked muscle response. Seven studies measured corticospinal excitability using motor evoked potentials (MEPs) induced by transcranial magnetic stimulation (TMS), and one study measured somatosensory evoked potentials (SSEPs) following TSCS. Our findings indicated a decrease in the amplitude of H-reflex and long latency flexion reflex following AC-TSCS, alongside an increase in the amplitudes of SMEPs and CMEPs. Moreover, the application of the TSCS-TMS paired associative technique resulted in spinal reflex inhibition, manifested by reduced amplitudes in both the H-reflex and flexion reflex arc. In terms of corticospinal excitability, findings from 5 studies demonstrated an increase in the amplitude of MEPs linked to lower limb muscles following DC-TSCS, in addition to paired associative stimulation involving repetitive TMS on the brain and DC-TSCS on the spine. There was an observed improvement in the latency of SSEPs in a single study. Notably, the overall quality of evidence, assessed by the modified Downs and Black Quality assessment, was deemed poor. Discussion This review unveils the systematic evidence supporting the potential of TSCS in reshaping both spinal and supraspinal neuronal circuitries post-SCI. Yet, it underscores the critical necessity for more rigorous, high-quality investigations.
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Affiliation(s)
- Shirin Tajali
- KITE Research Institute – University Health Network, Toronto, ON, Canada
| | - Gustavo Balbinot
- KITE Research Institute – University Health Network, Toronto, ON, Canada
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
- Center for Advancing Neurotechnological Innovation to Application – CRANIA, University Health Network, Toronto, ON, Canada
| | - Maureen Pakosh
- Library & Information Services, University Health Network, Toronto Rehabilitation Institute, ON, Canada
| | - Dimitry G. Sayenko
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX, United States
| | - Jose Zariffa
- KITE Research Institute – University Health Network, Toronto, ON, Canada
- Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Rehabilitation Sciences Institute, University of Toronto, Toronto, ON, Canada
| | - Kei Masani
- KITE Research Institute – University Health Network, Toronto, ON, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
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Skiadopoulos A, Knikou M. Tapping into the human spinal locomotor centres with transspinal stimulation. Sci Rep 2024; 14:5990. [PMID: 38472313 PMCID: PMC10933285 DOI: 10.1038/s41598-024-56579-0] [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: 12/28/2023] [Accepted: 03/08/2024] [Indexed: 03/14/2024] Open
Abstract
Human locomotion is controlled by spinal neuronal networks of similar properties, function, and organization to those described in animals. Transspinal stimulation affects the spinal locomotor networks and is used to improve standing and walking ability in paralyzed people. However, the function of locomotor centers during transspinal stimulation at different frequencies and intensities is not known. Here, we document the 3D joint kinematics and spatiotemporal gait characteristics during transspinal stimulation at 15, 30, and 50 Hz at sub-threshold and supra-threshold stimulation intensities. We document the temporal structure of gait patterns, dynamic stability of joint movements over stride-to-stride fluctuations, and limb coordination during walking at a self-selected speed in healthy subjects. We found that transspinal stimulation (1) affects the kinematics of the hip, knee, and ankle joints, (2) promotes a more stable coordination at the left ankle, (3) affects interlimb coordination of the thighs, and (4) intralimb coordination between thigh and foot, (5) promotes greater dynamic stability of the hips, (6) increases the persistence of fluctuations in step length variability, and lastly (7) affects mechanical walking stability. These results support that transspinal stimulation is an important neuromodulatory strategy that directly affects gait symmetry and dynamic stability. The conservation of main effects at different frequencies and intensities calls for systematic investigation of stimulation protocols for clinical applications.
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Affiliation(s)
- Andreas Skiadopoulos
- Klab4Recovery Research Program, The City University of New York, New York, USA
- Department of Physical Therapy, College of Staten Island, The City University of New York, Staten Island, NY, USA
| | - Maria Knikou
- Klab4Recovery Research Program, The City University of New York, New York, USA.
- Department of Physical Therapy, College of Staten Island, The City University of New York, Staten Island, NY, USA.
- PhD Program in Biology and Collaborative Neuroscience Program, Graduate Center of The City University of New York and College of Staten Island, New York, USA.
- Klab4Recovery Research Program, Neurosciences/Graduate Center of CUNY, DPT Department/College of Staten Island, 2800 Victory Blvd, 5N-207, New York, 10314, USA.
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Skiadopoulos A, Knikou M. Tapping Into the Human Spinal Locomotor Centres With Transspinal Stimulation. RESEARCH SQUARE 2024:rs.3.rs-3818499. [PMID: 38260677 PMCID: PMC10802712 DOI: 10.21203/rs.3.rs-3818499/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Human locomotion is controlled by spinal neuronal networks of similar properties, function, and organization to those described in animals. Transspinal stimulation affects the spinal locomotor networks and is used to improve standing and walking ability in paralyzed people. However, the function of locomotor centers during transspinal stimulation at different frequencies and intensities is not known. Here, we document the 3D joint kinematics and spatiotemporal gait characteristics during transspinal stimulation at 15, 30, and 50 Hz at sub-threshold and supra-threshold stimulation intensities. We document the temporal structure of gait patterns, dynamic stability of joint movements over stride-to-stride fluctuations, and limb coordination during walking at a self-selected speed in healthy subjects. We found that transspinal stimulation 1) affects the kinematics of the hip, knee, and ankle joints, 2) promotes a more stable coordination at the left ankle, 3) improves interlimb coordination of the thighs, 4) improves intralimb coordination between thigh and foot, 5) promotes greater dynamic stability of the hips, and lastly 6) affects the mechanical stability of the joints. These results support that transspinal stimulation is an important neuromodulatory strategy that directly affects gait symmetry and dynamic stability. The conservation of main effects at different frequencies and intensities calls for systematic investigation of stimulation protocols for clinical applications.
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Affiliation(s)
| | - Maria Knikou
- City University of New York and College of Staten Island
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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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ALCAN V, ZİNNUROĞLU M. Current developments in surface electromyography. Turk J Med Sci 2023; 53:1019-1031. [PMID: 38813041 PMCID: PMC10763750 DOI: 10.55730/1300-0144.5667] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 10/26/2023] [Accepted: 03/26/2023] [Indexed: 05/31/2024] Open
Abstract
Background/aim Surface electromyography (surface EMG) is a primary technique to detect the electrical activities of muscles through surface electrodes. In recent years, surface EMG applications have grown from conventional fields into new fields. However, there is a gap between the progress in the research of surface EMG and its clinical acceptance, characterized by the translational knowledge and skills in the widespread use of surface EMG among the clinician community. To reduce this gap, it is necessary to translate the updated surface EMG applications and technological advances into clinical research. Therefore, we aimed to present a perspective on recent developments in the application of surface EMG and signal processing methods. Materials and methods We conducted this scoping review following the Joanna Briggs Institute (JBI) method. We conducted a general search of PubMed and Web of Science to identify key search terms. Following the search, we uploaded selected articles into Rayyan and removed duplicates. After prescreening 133 titles and abstracts, we assessed 91 full texts according to the inclusion criteria. Results We concluded that surface EMG has made innovative technological progress and has research potential for routine clinical applications and a wide range of applications, such as neurophysiology, sports and art performances, biofeedback, physical therapy and rehabilitation, assessment of physical exercises, muscle strength, fatigue, posture and postural control, movement analysis, muscle coordination, motor synergies, modelling, and more. Novel methods have been applied for surface EMG signals in terms of time domain, frequency domain, time-frequency domain, statistical methods, and nonlinear methods. Conclusion Translating innovations in surface EMG and signal analysis methods into routine clinical applications can be a helpful tool with a growing and valuable role in muscle activation measurement in clinical practices. Thus, researchers must build many more interfaces that give opportunities for continuing education and research with more contemporary techniques and devices.
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Affiliation(s)
- Veysel ALCAN
- Department of Electrical and Electronics Engineering, Engineering Faculty, Tarsus University, Mersin,
Turkiye
| | - Murat ZİNNUROĞLU
- Department of Physical Medicine and Rehabilitation, Faculty of Medicine, Gazi University, Ankara,
Turkiye
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9
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Skiadopoulos A, Pulverenti TS, Knikou M. Physiological effects of cathodal electrode configuration for transspinal stimulation in humans. J Neurophysiol 2022; 128:1663-1682. [PMID: 36416443 PMCID: PMC9762966 DOI: 10.1152/jn.00342.2022] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 11/16/2022] [Accepted: 11/17/2022] [Indexed: 11/24/2022] Open
Abstract
Transspinal stimulation modulates neuronal excitability and promotes recovery in upper motoneuron lesions. The recruitment input-output curves of transspinal evoked potentials (TEPs) recorded from knee and ankle muscles, and their susceptibility to spinal inhibition, were recorded when the position, size, and number of the cathode electrode were arranged in four settings or protocols (Ps). The four Ps were the following: 1) one rectangular electrode placed at midline (KNIKOU-LAB4Recovery or K-LAB4Recovery; P-KLAB), 2) one square electrode placed at midline (P-2), 3) two square electrodes 1 cm apart placed at midline (P-3), and 4) one square electrode placed on each paravertebral side (P-4). P-KLAB and P-3 required less current to reach TEP threshold or maximal amplitudes. A rightward shift in TEP recruitment curves was evident for P-4, whereas the slope was increased for P-2 and P-4 compared with P-KLAB and P-3. TEP depression upon single and paired transspinal stimuli was pronounced in ankle TEPs but was less prominent in knee TEPs. TEP depression induced by single transspinal stimuli at 1.0 Hz was similar for most TEPs across protocols, but TEP depression induced by paired transspinal stimuli was different between protocols and was replaced by facilitation at 100-ms interstimulus interval for P-4. Our results suggest that P-KLAB and P-3 are preferred based on excitability threshold of motoneurons. P-KLAB produced more TEP depression, thereby maximizing the engagement of spinal neuronal pathways. We recommend P-KLAB to study neurophysiological mechanisms underlying transspinal stimulation or when used as a neuromodulation method for recovery in neurological disorders.NEW & NOTEWORTHY Transspinal stimulation with a rectangular cathode electrode (P-KLAB) requires less current to produce transspinal evoked potentials and maximizes spinal inhibition. We recommend P-KLAB for neurophysiological studies or when used as a neuromodulation method to enhance motor output and normalize muscle tone in neurological disorders.
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Affiliation(s)
- Andreas Skiadopoulos
- Klab4Recovery Research Program, The City University of New York, New York, New York
| | - Timothy S Pulverenti
- Klab4Recovery Research Program, The City University of New York, New York, New York
| | - Maria Knikou
- Klab4Recovery Research Program, The City University of New York, New York, New York
- Department of Physical Therapy, College of Staten Island, The City University of New York, Staten Island, New York
- PhD Program in Biology and Collaborative Neuroscience Program, Graduate Center of The City University of New York and College of Staten Island, Staten Island, New York
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10
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Solopova IA, Selionov VA, Blinov EO, Dolinskaya IY, Zhvansky DS, Lacquaniti F, Ivanenko Y. Higher Responsiveness of Pattern Generation Circuitry to Sensory Stimulation in Healthy Humans Is Associated with a Larger Hoffmann Reflex. BIOLOGY 2022; 11:biology11050707. [PMID: 35625435 PMCID: PMC9138260 DOI: 10.3390/biology11050707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 04/26/2022] [Accepted: 05/02/2022] [Indexed: 11/25/2022]
Abstract
Simple Summary Individual differences in the sensorimotor circuitry play an important role for understanding the nature of behavioral variability and developing personalized therapies. While the spinal network likely requires relatively rigid organization, it becomes increasingly evident that adaptability and inter-individual variability in the functioning of the neuronal circuitry is present not only in the brain but also in the spinal cord. In this study we investigated the relationship between the excitability of pattern generation circuitry and segmental reflexes in healthy humans. We found that the high individual responsiveness of pattern generation circuitries to tonic sensory input in both the upper and lower limbs was related to larger H-reflexes. The results provide further evidence for the importance of physiologically relevant assessments of spinal cord neuromodulation and the individual physiological state of reflex pathways. Abstract The state and excitability of pattern generators are attracting the increasing interest of neurophysiologists and clinicians for understanding the mechanisms of the rhythmogenesis and neuromodulation of the human spinal cord. It has been previously shown that tonic sensory stimulation can elicit non-voluntary stepping-like movements in non-injured subjects when their limbs were placed in a gravity-neutral unloading apparatus. However, large individual differences in responsiveness to such stimuli were observed, so that the effects of sensory neuromodulation manifest only in some of the subjects. Given that spinal reflexes are an integral part of the neuronal circuitry, here we investigated the extent to which spinal pattern generation excitability in response to the vibrostimulation of muscle proprioceptors can be related to the H-reflex magnitude, in both the lower and upper limbs. For the H-reflex measurements, three conditions were used: stationary limbs, voluntary limb movement and passive limb movement. The results showed that the H-reflex was considerably higher in the group of participants who demonstrated non-voluntary rhythmic responses than it was in the participants who did not demonstrate them. Our findings are consistent with the idea that spinal reflex measurements play important roles in assessing the rhythmogenesis of the spinal cord.
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Affiliation(s)
- Irina A. Solopova
- Laboratory of Neurobiology of Motor Control, Institute for Information Transmission Problems, Russian Academy of Sciences, 127951 Moscow, Russia; (I.A.S.); (V.A.S.); (I.Y.D.); (D.S.Z.)
| | - Victor A. Selionov
- Laboratory of Neurobiology of Motor Control, Institute for Information Transmission Problems, Russian Academy of Sciences, 127951 Moscow, Russia; (I.A.S.); (V.A.S.); (I.Y.D.); (D.S.Z.)
| | - Egor O. Blinov
- School of Biological and Medical Physics, Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia;
| | - Irina Y. Dolinskaya
- Laboratory of Neurobiology of Motor Control, Institute for Information Transmission Problems, Russian Academy of Sciences, 127951 Moscow, Russia; (I.A.S.); (V.A.S.); (I.Y.D.); (D.S.Z.)
- School of Biological and Medical Physics, Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia;
| | - Dmitry S. Zhvansky
- Laboratory of Neurobiology of Motor Control, Institute for Information Transmission Problems, Russian Academy of Sciences, 127951 Moscow, Russia; (I.A.S.); (V.A.S.); (I.Y.D.); (D.S.Z.)
| | - Francesco Lacquaniti
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, 00179 Rome, Italy;
- Department of Systems Medicine and Center of Space Biomedicine, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Yury Ivanenko
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, 00179 Rome, Italy;
- Correspondence:
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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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