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Adury RZ, Siu R, Jung R. Co-activation of the diaphragm and external intercostal muscles through an adaptive closed-loop respiratory pacing controller. FRONTIERS IN REHABILITATION SCIENCES 2023; 4:1199722. [PMID: 37484600 PMCID: PMC10360177 DOI: 10.3389/fresc.2023.1199722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 06/20/2023] [Indexed: 07/25/2023]
Abstract
Introduction Respiratory pacing is a promising alternative to traditional mechanical ventilation that has been shown to significantly increase the survival and quality of life after the neural control of the respiratory system has been compromised. However, current pacing approaches to achieve adequate ventilation tend to target only the diaphragm without pacing external intercostal muscles that are also activated during normal inspiration. Furthermore, the pacing paradigms do not allow for intermittent sighing, which carries an important physiological role. We hypothesized that simultaneous activation of the diaphragm and external intercostal muscles would improve the efficiency of respiratory pacing compared to diaphragm stimulation alone. Materials and Methods We expanded an adaptive, closed-loop diaphragm pacing paradigm we had previously developed to include external intercostal muscle activation and sigh generation. We then investigated, using a rodent model for respiratory pacing, if simultaneous activation would delay the fatigability of the diaphragm during pacing and allow induction of appropriate sigh-like behavior in spontaneously breathing un-injured anesthetized rats (n = 8) with pacing electrodes implanted bilaterally in the diaphragm and external intercostal muscles, between 2nd and 3rd intercostal spaces. Results With this novel pacing system, we show that fatigability of the diaphragm was lower when using combined muscle stimulation than diaphragm stimulation alone (p = 0.014) and that combined muscle stimulation was able to induce sighs with significantly higher tidal volumes compared to diaphragm stimulation alone (p = 0.014). Conclusion Our findings demonstrate that simultaneous activation of the inspiratory muscles could be used as a suitable strategy to delay stimulation-induced diaphragmatic fatigue and to induce a sigh-like behavior that could improve respiratory health.
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Affiliation(s)
- Rabeya Zinnat Adury
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
- Department of Biomedical Engineering, Florida International University, Miami, FL, United States
| | - Ricardo Siu
- Department of Biomedical Engineering, Florida International University, Miami, FL, United States
- Department of Physical Medicine and Rehabilitation, Case Western Reserve University, Cleveland, OH, United States
| | - Ranu Jung
- Department of Biomedical Engineering, Florida International University, Miami, FL, United States
- Department of Biomedical Engineering, The Institute for Integrative and Innovative Research (IR), University of Arkansas, Fayetteville, AR, United States
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Autonomous control of ventilation through closed-loop adaptive respiratory pacing. Sci Rep 2020; 10:21903. [PMID: 33318547 PMCID: PMC7736353 DOI: 10.1038/s41598-020-78834-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 12/01/2020] [Indexed: 02/06/2023] Open
Abstract
Mechanical ventilation is the standard treatment when volitional breathing is insufficient, but drawbacks include muscle atrophy, alveolar damage, and reduced mobility. Respiratory pacing is an alternative approach using electrical stimulation-induced diaphragm contraction to ventilate the lung. Oxygenation and acid-base homeostasis are maintained by matching ventilation to metabolic needs; however, current pacing technology requires manual tuning and does not respond to dynamic user-specific metabolic demand, thus requiring re-tuning of stimulation parameters as physiological changes occur. Here, we describe respiratory pacing using a closed-loop adaptive controller that can self-adjust in real-time to meet metabolic needs. The controller uses an adaptive Pattern Generator Pattern Shaper (PG/PS) architecture that autonomously generates a desired ventilatory pattern in response to dynamic changes in arterial CO2 levels and, based on a learning algorithm, modulates stimulation intensity and respiratory cycle duration to evoke this ventilatory pattern. In vivo experiments in rats with respiratory depression and in those with a paralyzed hemidiaphragm confirmed that the controller can adapt and control ventilation to ameliorate hypoventilation and restore normocapnia regardless of the cause of respiratory dysfunction. This novel closed-loop bioelectronic controller advances the state-of-art in respiratory pacing by demonstrating the ability to automatically personalize stimulation patterns and adapt to achieve adequate ventilation.
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Siu R, Abbas JJ, Hillen BK, Gomes J, Coxe S, Castelli J, Renaud S, Jung R. Restoring Ventilatory Control Using an Adaptive Bioelectronic System. J Neurotrauma 2019; 36:3363-3377. [PMID: 31146654 DOI: 10.1089/neu.2018.6358] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Ventilatory pacing by electrical stimulation of the phrenic nerve or of the diaphragm has been shown to enhance quality of life compared to mechanical ventilation. However, commercially available ventilatory pacing devices require initial manual specification of stimulation parameters and frequent adjustment to achieve and maintain suitable ventilation over long periods of time. Here, we have developed an adaptive, closed-loop, neuromorphic, pattern-shaping controller capable of automatically determining a suitable stimulation pattern and adapting it to maintain a desired breath-volume profile on a breath-by-breath basis. The system adapts the pattern of stimulation parameters based on the error between the measured volume sampled every 40 ms and a desired breath volume profile. In vivo studies in anesthetized male Sprague-Dawley rats without and with spinal cord injury by spinal hemisection at C2 indicated that the controller was capable of automatically adapting stimulation parameters to attain a desired volume profile. Despite diaphragm hemiparesis, the controller was able to achieve a desired volume in the injured animals that did not differ from the tidal volume observed before injury (p = 0.39). Closed-loop adaptive pacing partially mitigated hypoventilation as indicated by reduction of end-tidal CO2 values during pacing. The closed-loop controller was developed and parametrized in a computational testbed before in vivo assessment. This bioelectronic technology could serve as an individualized and autonomous respiratory pacing approach for support or recovery from ventilatory deficiency.
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Affiliation(s)
- Ricardo Siu
- Department of Biomedical Engineering, Florida International University, Miami, Florida
| | - James J Abbas
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona
| | - Brian K Hillen
- Department of Biomedical Engineering, Florida International University, Miami, Florida
| | - Jefferson Gomes
- Department of Biomedical Engineering, Florida International University, Miami, Florida
| | - Stefany Coxe
- Department of Psychology, Florida International University, Miami, Florida
| | - Jonathan Castelli
- Université de Bordeaux, INP Bordeaux, IMS CNRS UMR 5218, Bordeaux, France
| | - Sylvie Renaud
- Université de Bordeaux, INP Bordeaux, IMS CNRS UMR 5218, Bordeaux, France
| | - Ranu Jung
- Department of Biomedical Engineering, Florida International University, Miami, Florida
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Zbrzeski A, Bornat Y, Hillen B, Siu R, Abbas J, Jung R, Renaud S. Bio-Inspired Controller on an FPGA Applied to Closed-Loop Diaphragmatic Stimulation. Front Neurosci 2016; 10:275. [PMID: 27378844 PMCID: PMC4909776 DOI: 10.3389/fnins.2016.00275] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 06/01/2016] [Indexed: 12/02/2022] Open
Abstract
Cervical spinal cord injury can disrupt connections between the brain respiratory network and the respiratory muscles which can lead to partial or complete loss of ventilatory control and require ventilatory assistance. Unlike current open-loop technology, a closed-loop diaphragmatic pacing system could overcome the drawbacks of manual titration as well as respond to changing ventilation requirements. We present an original bio-inspired assistive technology for real-time ventilation assistance, implemented in a digital configurable Field Programmable Gate Array (FPGA). The bio-inspired controller, which is a spiking neural network (SNN) inspired by the medullary respiratory network, is as robust as a classic controller while having a flexible, low-power and low-cost hardware design. The system was simulated in MATLAB with FPGA-specific constraints and tested with a computational model of rat breathing; the model reproduced experimentally collected respiratory data in eupneic animals. The open-loop version of the bio-inspired controller was implemented on the FPGA. Electrical test bench characterizations confirmed the system functionality. Open and closed-loop paradigm simulations were simulated to test the FPGA system real-time behavior using the rat computational model. The closed-loop system monitors breathing and changes in respiratory demands to drive diaphragmatic stimulation. The simulated results inform future acute animal experiments and constitute the first step toward the development of a neuromorphic, adaptive, compact, low-power, implantable device. The bio-inspired hardware design optimizes the FPGA resource and time costs while harnessing the computational power of spike-based neuromorphic hardware. Its real-time feature makes it suitable for in vivo applications.
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Affiliation(s)
- Adeline Zbrzeski
- Bordeaux INP, IMS, UMR 5218Talence, France; Univ. Bordeaux, IMS, UMR 5218Talence, France
| | - Yannick Bornat
- Bordeaux INP, IMS, UMR 5218Talence, France; Univ. Bordeaux, IMS, UMR 5218Talence, France
| | - Brian Hillen
- Department of Biomedical Engineering, Florida International University Miami, FL, USA
| | - Ricardo Siu
- Department of Biomedical Engineering, Florida International University Miami, FL, USA
| | - James Abbas
- School of Biological and Health Systems Engineering, Arizona State University Tempe, AZ, USA
| | - Ranu Jung
- Department of Biomedical Engineering, Florida International University Miami, FL, USA
| | - Sylvie Renaud
- Bordeaux INP, IMS, UMR 5218Talence, France; Univ. Bordeaux, IMS, UMR 5218Talence, France
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Hillen BK, Abbas JJ, Zbrzeski A, Renaud S, Jung R. Adaptive control of ventilation using electrical stimulation in a biomechanical model. BMC Neurosci 2015. [PMCID: PMC4697536 DOI: 10.1186/1471-2202-16-s1-p111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Beaumont E, Guevara E, Dubeau S, Lesage F, Nagai M, Popovic M. Functional electrical stimulation post-spinal cord injury improves locomotion and increases afferent input into the central nervous system in rats. J Spinal Cord Med 2014; 37:93-100. [PMID: 24090649 PMCID: PMC4066556 DOI: 10.1179/2045772313y.0000000117] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
BACKGROUND Functional electrical stimulation (FES) has been found to be effective in restoring voluntary functions after spinal cord injury (SCI) and stroke. However, the central nervous system (CNS) changes that occur in as a result of this therapy are largely unknown. OBJECTIVE To examine the effects of FES on the restoration of voluntary locomotor function of the CNS in a SCI rat model. METHODS SCI rats were instrumented with chronic FES electrodes in the hindlimb muscles and were divided into two groups: (a) FES therapy and (b) sedentary. At day 7 post-SCI, the animals were assessed for locomotion performance by using a Basso, Beattie and Bresnahan (BBB) scale. They were then anesthetized for a terminal in vivo experiment. The lumbar spinal cord and somatosensory cortex were exposed and the instrumented muscles were stimulated electrically. Associated neurovascular responses in the CNS were recorded with an intrinsic optical imaging system. RESULTS FES greatly improved locomotion recovery by day 7 post-SCI, as measured by BBB scores (P < 0.05): (a) FES 10 ± 2 and (b) controls 3 ± 1. Furthermore, the FES group showed a significant increase (P < 0.05) of neurovascular activation in the spinal cord and somatosensory cortex when the muscles were stimulated between 1 and 3 motor threshold (MT). CONCLUSION Hind limb rehabilitation with FES is an effective strategy to improve locomotion during the acute phase post-SCI. The results of this study indicate that after FES, the CNS preserves/acquires the capacity to respond to peripheral electrical stimulation.
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Affiliation(s)
- Eric Beaumont
- Department of Biomedical Sciences, East Tennessee State University, Mountain Home, TN, USA,Correspondence to: Eric Beaumont, PhD, East Tennessee State University, Department of Biomedical Sciences, One Dogwood Ave., VA building #119, rm 1-36, Mountain Home, TN 37684, USA.
| | - Edgar Guevara
- Département de génie électrique, École Polytechnique de Montréal, Montréal, Québec, Canada
| | - Simon Dubeau
- Département de génie électrique, École Polytechnique de Montréal, Montréal, Québec, Canada
| | - Frederic Lesage
- Département de génie électrique, École Polytechnique de Montréal, Montréal, Québec, Canada
| | - Mary Nagai
- Département de génie électrique, École Polytechnique de Montréal, Montréal, Québec, Canada
| | - Milos Popovic
- Rehabilitation Engineering Laboratory, Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
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Hillen BK, Abbas JJ, Jung R. Accelerating locomotor recovery after incomplete spinal injury. Ann N Y Acad Sci 2013; 1279:164-74. [PMID: 23531014 DOI: 10.1111/nyas.12061] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A traumatic spinal injury can destroy cells, irreparably damage axons, and trigger a cascade of biochemical responses that increase the extent of injury. Although damaged central nervous system axons do not regrow well naturally, the distributed nature of the nervous system and its capacity to adapt provide opportunities for recovery of function. It is apparent that activity-dependent plasticity plays a role in this recovery and that the endogenous response to injury heightens the capacity for recovery for at least several weeks postinjury. To restore locomotor function, researchers have investigated the use of treadmill-based training, robots, and electrical stimulation to tap into adaptive activity-dependent processes. The current challenge is to maximize the degree of functional recovery. This manuscript reviews the endogenous neural system response to injury, and reviews data and presents novel analyses of these from a rat model of contusion injury that demonstrates how a targeted intervention can accelerate recovery, presumably by engaging processes that underlie activity-dependent plasticity.
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Affiliation(s)
- Brian K Hillen
- Department of Biomedical Engineering, Florida International University, Miami, FL 33174, USA
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Shen X, Wang Z, Lv X, Huang Z. Microelectronic neural bridging of toad nerves to restore leg function. Neural Regen Res 2013; 8:546-53. [PMID: 25206698 PMCID: PMC4146052 DOI: 10.3969/j.issn.1673-5374.2013.06.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2012] [Accepted: 12/26/2012] [Indexed: 11/20/2022] Open
Abstract
The present study used a microelectronic neural bridge comprised of electrode arrays for neural signal detection, functional electrical stimulation, and a microelectronic circuit including signal amplifying, processing, and functional electrical stimulation to bridge two separate nerves, and to restore the lost function of one nerve. The left leg of one spinal toad was subjected to external mechanical stimulation and functional electrical stimulation driving. The function of the left leg of one spinal toad was regenerated to the corresponding leg of another spinal toad using a microelectronic neural bridge. Oscilloscope tracings showed that the electromyographic signals from controlled spinal toads were generated by neural signals that controlled the spinal toad, and there was a delay between signals. This study demonstrates that microelectronic neural bridging can be used to restore neural function between different injured nerves.
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Affiliation(s)
- Xiaoyan Shen
- School of Electronic Information, Nantong University, Nantong 226007, Jiangsu Province, China ; Institute of RF- & OE-ICs, Southeast University, Nanjing 210096, Jiangsu Province, China
| | - Zhigong Wang
- Institute of RF- & OE-ICs, Southeast University, Nanjing 210096, Jiangsu Province, China
| | - Xiaoying Lv
- State Key Laboratory of Bioelectronics, Southeast University, Nanjing 210096, Jiangsu Province, China
| | - Zonghao Huang
- Institute of RF- & OE-ICs, Southeast University, Nanjing 210096, Jiangsu Province, China
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Jarc AM, Berniker M, Tresch MC. FES control of isometric forces in the rat hindlimb using many muscles. IEEE Trans Biomed Eng 2013; 60:1422-30. [PMID: 23303688 DOI: 10.1109/tbme.2013.2237768] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Functional electrical stimulation (FES) attempts to restore motor behaviors to paralyzed limbs by electrically stimulating nerves and/or muscles. This restoration of behavior requires specifying commands to a large number of muscles, each making an independent contribution to the ongoing behavior. Efforts to develop FES systems in humans have generally been limited to preprogrammed, fixed muscle activation patterns. The development and evaluation of more sophisticated FES control strategies is difficult to accomplish in humans, mainly because of the limited access of patients for FES experiments. Here, we developed an in vivo FES test platform using a rat model that is capable of using many muscles for control and that can therefore be used to evaluate potential strategies for developing flexible FES control strategies. We first validated this FES test platform by showing consistent force responses to repeated stimulation, monotonically increasing muscle recruitment with constant force directions, and linear summation of costimulated muscles. These results demonstrate that we are able to differentially control the activation of many muscles, despite the small size of the rat hindlimb. We then demonstrate the utility of this platform to test potential FES control strategies, using it to test our ability to effectively produce open-loop control of isometric forces. We show that we are able to use this preparation to produce a range of endpoint forces flexibly and with good accuracy. We suggest that this platform will aid in FES controller design, development, and evaluation, thus accelerating the development of effective FES applications for the restoration of movement in paralyzed patients.
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Askari S, Chao T, de Leon RD, Won DS. The effect of timing electrical stimulation to robotic-assisted stepping on neuromuscular activity and associated kinematics. ACTA ACUST UNITED AC 2013; 50:875-92. [DOI: 10.1682/jrrd.2012.06.0111] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
| | | | - Ray D. de Leon
- School of Kinesiology and Nutritional Science, California State University, Los Angeles, CA
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Guo X, Ayala JE, Gonzalez M, Stancescu M, Lambert S, Hickman JJ. Tissue engineering the monosynaptic circuit of the stretch reflex arc with co-culture of embryonic motoneurons and proprioceptive sensory neurons. Biomaterials 2012; 33:5723-31. [PMID: 22594977 DOI: 10.1016/j.biomaterials.2012.04.042] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Accepted: 04/16/2012] [Indexed: 01/08/2023]
Abstract
The sensory circuit of the stretch reflex arc is composed of intrafusal muscle fibers and their innervating proprioceptive neurons that convert mechanical information regarding muscle length and tension into action potentials that synapse onto the homonymous motoneurons in the ventral spinal cord which innervate the extrafusal fibers of the same muscle. To date, the in vitro synaptic connection between proprioceptive sensory neurons and spinal motoneurons has not been demonstrated. A functional in vitro system demonstrating this connection would enable the understanding of feedback by the integration of sensory input into the spinal reflex arc. Here we report a co-culture of rat embryonic motoneurons and proprioceptive sensory neurons from dorsal root ganglia (DRG) in a defined serum-free medium on a synthetic silane substrate (DETA). Furthermore, we have demonstrated functional synapse formation in the co-culture by immunocytochemistry and electrophysiological analysis. This work will be valuable for enabling in vitro model systems for the study of spinal motor control and related pathologies such as spinal cord injury, muscular dystrophy and spasticity by improving our understanding of the integration of the mechanosensitive feedback mechanism.
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Affiliation(s)
- Xiufang Guo
- Hybrid Systems Lab, NanoScience Technology Center, University of Central Florida, 12424 Research Parkway, Suite 400, Orlando, FL 32826, USA
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Kanchiku T, Kato Y, Suzuki H, Imajo Y, Yoshida Y, Moriya A, Taguchi T, Jung R. Development of less invasive neuromuscular electrical stimulation model for motor therapy in rodents. J Spinal Cord Med 2012; 35:162-9. [PMID: 22507026 PMCID: PMC3324833 DOI: 10.1179/2045772312y.0000000009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
BACKGROUND Combination therapy is essential for functional repairs of the spinal cord. Rehabilitative therapy can be considered as the key for reorganizing the nervous system after spinal cord regeneration therapy. Functional electrical stimulation has been used as a neuroprosthesis in quadriplegia and can be used for providing rehabilitative therapy to tap the capability for central nervous system reorganization after spinal cord regeneration therapy. OBJECTIVE To develop a less invasive muscular electrical stimulation model capable of being combined with spinal cord regeneration therapy especially for motor therapy in the acute stage after spinal cord injury. METHODS The tibialis anterior and gastrocnemius motor points were identified in intact anesthetized adult female Fischer rats, and stimulation needle electrodes were percutaneously inserted into these points. Threshold currents for visual twitches were obtained upon stimulation using pulses of 75 or 8 kHz for 200 ms. Biphasic pulse widths of 20, 40, 80, 100, 300, and 500 µs per phase were used to determine strength-duration curves. Using these parameters and previously obtained locomotor electromyogram data, stimulations were performed on bilateral joint muscle pairs to produce reciprocal flexion/extension movements of the ankle for 15 minutes while three-dimensional joint kinematics were assessed. RESULTS Rhythmic muscular electrical stimulation with needle electrodes was successfully done, but decreased range of motion (ROM) over time. High-frequency and high-amplitude stimulation was also shown to be effective in alleviating decreases in ROM due to muscle fatigue. CONCLUSIONS This model will be useful for investigating the ability of rhythmic muscular electrical stimulation therapy to promote motor recovery, in addition to the efficacy of combining treatments with spinal cord regeneration therapy after spinal cord injuries.
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Affiliation(s)
- Tsukasa Kanchiku
- Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan.
| | - Yoshihiko Kato
- Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan
| | - Hidenori Suzuki
- Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan
| | - Yasuaki Imajo
- Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan
| | - Yuichiro Yoshida
- Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan
| | - Atsushi Moriya
- Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan
| | - Toshihiko Taguchi
- Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan
| | - Ranu Jung
- Florida International University, Miami, FL, USA
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