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Dalrymple AN, Fisher LE, Weber DJ. A preliminary study exploring the effects of transcutaneous spinal cord stimulation on spinal excitability and phantom limb pain in people with a transtibial amputation. J Neural Eng 2024; 21:046058. [PMID: 39094627 PMCID: PMC11391861 DOI: 10.1088/1741-2552/ad6a8d] [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: 10/21/2023] [Accepted: 08/02/2024] [Indexed: 08/04/2024]
Abstract
Objective. Phantom limb pain (PLP) is debilitating and affects over 70% of people with lower-limb amputation. Other neuropathic pain conditions correspond with increased spinal excitability, which can be measured using reflexes andF-waves. Spinal cord neuromodulation can be used to reduce neuropathic pain in a variety of conditions and may affect spinal excitability, but has not been extensively used for treating PLP. Here, we propose using a non-invasive neuromodulation method, transcutaneous spinal cord stimulation (tSCS), to reduce PLP and modulate spinal excitability after transtibial amputation.Approach. We recruited three participants, two males (5- and 9-years post-amputation, traumatic and alcohol-induced neuropathy) and one female (3 months post-amputation, diabetic neuropathy) for this 5 d study. We measured pain using the McGill Pain Questionnaire (MPQ), visual analog scale (VAS), and pain pressure threshold (PPT) test. We measured spinal reflex and motoneuron excitability using posterior root-muscle (PRM) reflexes andF-waves, respectively. We delivered tSCS for 30 min d-1for 5 d.Main Results. After 5 d of tSCS, MPQ scores decreased by clinically-meaningful amounts for all participants from 34.0 ± 7.0-18.3 ± 6.8; however, there were no clinically-significant decreases in VAS scores. Two participants had increased PPTs across the residual limb (Day 1: 5.4 ± 1.6 lbf; Day 5: 11.4 ± 1.0 lbf).F-waves had normal latencies but small amplitudes. PRM reflexes had high thresholds (59.5 ± 6.1μC) and low amplitudes, suggesting that in PLP, the spinal cord is hypoexcitable. After 5 d of tSCS, reflex thresholds decreased significantly (38.6 ± 12.2μC;p< 0.001).Significance. These preliminary results in this non-placebo-controlled study suggest that, overall, limb amputation and PLP may be associated with reduced spinal excitability and tSCS can increase spinal excitability and reduce PLP.
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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
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States of America
- Department of Physical Medicine & Rehabilitation, University of Utah, Salt Lake City, UT, United States of America
- NERVES Lab, University of Utah, Salt Lake City, UT, United States of America
| | - Lee E Fisher
- Department of Physical Medicine & Rehabilitation, University of Pittsburgh, Pittsburgh, PA, United States of America
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for Neural Basis of Cognition, Pittsburgh, PA, United States of America
- Rehab Neural Engineering Labs, University of Pittsburgh, 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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Keesey R, Hofstoetter U, Hu Z, Lombardi L, Hawthorn R, Bryson N, Rowald A, Minassian K, Seáñez I. FUNDAMENTAL LIMITATIONS OF KILOHERTZ-FREQUENCY CARRIERS IN AFFERENT FIBER RECRUITMENT WITH TRANSCUTANEOUS SPINAL CORD STIMULATION. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.26.603982. [PMID: 39211255 PMCID: PMC11361147 DOI: 10.1101/2024.07.26.603982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
The use of kilohertz-frequency (KHF) waveforms has rapidly gained momentum in transcutaneous spinal cord stimulation (tSCS) to restore motor function after paralysis. However, the mechanisms by which these fast-alternating currents depolarize efferent and afferent fibers remain unknown. Our study fills this research gap by providing a hypothesis-and evidence-based investigation using peripheral nerve stimulation, lumbar tSCS, and cervical tSCS in 25 unimpaired participants together with computational modeling. Peripheral nerve stimulation experiments and computational modeling showed that KHF waveforms negatively impact the processes required to elicit action potentials, thereby increasing response thresholds and biasing the recruitment towards efferent fibers. While these results translate to tSCS, we also demonstrate that lumbar tSCS results in the preferential recruitment of afferent fibers, while cervical tSCS favors recruitment of efferent fibers. Given the assumed importance of proprioceptive afferents in motor recovery, our work suggests that the use of KHF waveforms should be reconsidered to maximize neurorehabilitation outcomes, particularly for cervical tSCS. We posit that careful analysis of the mechanisms that mediate responses elicited by novel approaches in tSCS is crucial to understanding their potential to restore motor function after paralysis.
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Rajnicek AM, Casañ-Pastor N. Wireless control of nerve growth using bipolar electrodes: a new paradigm in electrostimulation. Biomater Sci 2024; 12:2180-2202. [PMID: 38358306 DOI: 10.1039/d3bm01946b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2024]
Abstract
Electrical activity underpins all life, but is most familiar in the nervous system, where long range electrical signalling is essential for function. When this is lost (e.g., traumatic injury) or it becomes inefficient (e.g., demyelination), the use of external fields can compensate for at least some functional deficits. However, its potential to also promote biological repair at the cell level is underplayed despite abundant in vitro evidence for control of neuron growth. This perspective article considers specifically the emerging possibility of achieving cell growth through the interaction of external electric fields using conducting materials as unwired bipolar electrodes, and without intending stimulation of neuron electrical activity to be the primary consequence. The use of a wireless method to create electrical interactions represents a paradigm shift and may allow new applications in vivo where physical wiring is not possible. Within that scheme of thought an evaluation of specific materials and their dynamic responses as bipolar unwired electrodes is summarized and correlated with changes in dynamic nerve growth during stimulation, suggesting possible future schemes to achieve neural growth using bipolar unwired electrodes with specific characteristics. This strategy emphasizes how nerve growth can be encouraged at injury sites wirelessly to induce repair, as opposed to implanting devices that may substitute the neural signals.
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Affiliation(s)
- Ann M Rajnicek
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, AB25 2ZD, Scotland, United KIngdom
| | - Nieves Casañ-Pastor
- Institut de Ciència de Materials de Barcelona, CSIC, Campus UAB, 08193 Bellaterra, Barcelona, Spain.
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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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Zhang J, Wang M, Alam M, Zheng YP, Ye F, Hu X. Effects of non-invasive cervical spinal cord neuromodulation by trans-spinal electrical stimulation on cortico-muscular descending patterns in upper extremity of chronic stroke. Front Bioeng Biotechnol 2024; 12:1372158. [PMID: 38576448 PMCID: PMC10991759 DOI: 10.3389/fbioe.2024.1372158] [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: 03/11/2024] [Indexed: 04/06/2024] Open
Abstract
Background: Trans-spinal electrical stimulation (tsES) to the intact spinal cord poststroke may modulate the cortico-muscular control in stroke survivors with diverse lesions in the brain. This work aimed to investigate the immediate effects of tsES on the cortico-muscular descending patterns during voluntary upper extremity (UE) muscle contractions by analyzing cortico-muscular coherence (CMCoh) and electromyography (EMG) in people with chronic stroke. Methods: Twelve chronic stroke participants were recruited to perform wrist-hand extension and flexion tasks at submaximal levels of voluntary contraction for the corresponding agonist flexors and extensors. During the tasks, the tsES was delivered to the cervical spinal cord with rectangular biphasic pulses. Electroencephalography (EEG) data were collected from the sensorimotor cortex, and the EMG data were recorded from both distal and proximal UE muscles. The CMCoh, laterality index (LI) of the peak CMCoh, and EMG activation level parameters under both non-tsES and tsES conditions were compared to evaluate the immediate effects of tsES on the cortico-muscular descending pathway. Results: The CMCoh and LI of peak CMCoh in the agonist distal muscles showed significant increases (p < 0.05) during the wrist-hand extension and flexion tasks with the application of tsES. The EMG activation levels of the antagonist distal muscle during wrist-hand extension were significantly decreased (p < 0.05) with tsES. Additionally, the proximal UE muscles exhibited significant decreases (p < 0.05) in peak CMCoh and EMG activation levels by applying tsES. There was a significant increase (p < 0.05) in LI of peak CMCoh of proximal UE muscles during tsES. Conclusion: The cervical spinal cord neuromodulation via tsES enhanced the residual descending excitatory control, activated the local inhibitory circuits within the spinal cord, and reduced the cortical and proximal muscular compensatory effects. These results suggested the potential of tsES as a supplementary input for improving UE motor functions in stroke rehabilitation.
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Affiliation(s)
- Jianing Zhang
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Kowloon, China
| | - Maner Wang
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Kowloon, China
| | - Monzurul Alam
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Kowloon, China
| | - Yong-Ping Zheng
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Kowloon, China
| | - Fuqiang Ye
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Kowloon, China
| | - Xiaoling Hu
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Kowloon, China
- Research Institute for Smart Ageing (RISA), Hong Kong SAR, China
- Research Centre of Data Science and Artificial Intelligence (RC-DSAI), Hong Kong SAR, China
- Joint Research Centre for Biosensing and Precision Theranostics, Hong Kong SAR, China
- University Research Facility in Behavioral and Systems Neuroscience (UBSN), The Hong Kong Polytechnic University, Hong Kong SAR, China
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Pedrocchiguest A, Guanziroli E. Guest Editorial Special Section on Functional Recovery and Brain Plasticity. IEEE OPEN JOURNAL OF ENGINEERING IN MEDICINE AND BIOLOGY 2024; 4:275-277. [PMID: 38196974 PMCID: PMC10776091 DOI: 10.1109/ojemb.2023.3339954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 12/04/2023] [Indexed: 01/11/2024] Open
Abstract
The aim of rehabilitation after neurological damage is functional recovery, which includes motor, sensory, and cognitive aspects, which are closely interrelated [22].
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Affiliation(s)
- Alessandra Pedrocchiguest
- NEARLAB, Neuroengineering and Medical Robotics Laboratory, AND WE-COBOT, Wearable Collaborative Laboratory, Department of Electronics, Information and BioengineeringPolitecnico di MilanoMilanItaly
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