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Yuan R, Peng Y, Ji R, Zheng Y. Comparison of the activation level in the sensorimotor cortex between motor point and proximal nerve bundle electrical stimulation. J Neural Eng 2024; 21:026029. [PMID: 38537271 DOI: 10.1088/1741-2552/ad3850] [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: 11/07/2023] [Accepted: 03/27/2024] [Indexed: 04/06/2024]
Abstract
Objective.Neuromuscular electrical stimulation (NMES) is widely used for motor function rehabilitation in stroke survivors. Compared with the conventional motor point (MP) stimulation, the stimulation at the proximal segment of the peripheral nerve (PN) bundles has been demonstrated to have multiple advantages. However, it is not known yet whether the PN stimulation can increase the cortical activation level, which is crucial for motor function rehabilitation.Approach.The current stimuli were delivered transcutaneously at the muscle belly of the finger flexors and the proximal segment of the median and ulnar nerves, respectively for the MP and PN stimulation. The stimulation intensity was determined to elicit the same contraction levels between the two stimulation methods in 18 healthy individuals and a stroke patient. The functional near-infrared spectroscopy and the electromyogram were recorded to compare the activation pattern of the sensorimotor regions and the target muscles.Main Results.For the healthy subjects, the PN stimulation induced significantly increased concentration of the oxygenated hemoglobin in the contralateral sensorimotor areas, and enhanced the functional connectivity between brain regions compared with the MP stimulation. Meanwhile, the compound action potentials had a smaller amplitude and the H-reflex became stronger under the PN stimulation, indicating that more sensory axons were activated in the PN stimulation. For the stroke patient, the PN stimulation can elicit finger forces and induce activation of both the contralateral and ipsilateral motor cortex.Conclusions. Compared with the MP stimulation, the PN stimulation can induce more cortical activation in the contralateral sensorimotor areas possibly via involving more activities in the central pathway.Significance.This study demonstrated the potential of the PN stimulation to facilitate functional recovery via increasing the cortical activation level, which may help to improve the outcome of the NMES-based rehabilitation for motor function recovery after stroke.
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Affiliation(s)
- Rui Yuan
- Institute of Engineering and Medicine Interdisciplinary Studies and the State Key Laboratory for Manufacturing Systems Engineering, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Yu Peng
- Department of Rehabilitation, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Run Ji
- National Research Center for Rehabilitation Technical Aids and the Key Laboratory of Human Motion Analysis and Rehabilitation Technology of the Ministry of Civil Affairs, Beijing, People's Republic of China
| | - Yang Zheng
- Institute of Engineering and Medicine Interdisciplinary Studies and the State Key Laboratory for Manufacturing Systems Engineering, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, People's Republic of China
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Li R, Zhang P, Lu J, Zhuang J, Wang M, Fang H, Zhang X, Gao Y, Yang Z, Chin KL. Case report: Ultrasound-guided median nerve electrical stimulation on functional recovery of hemiplegic upper limb after stroke. Front Neurol 2023; 14:1244192. [PMID: 38046582 PMCID: PMC10691377 DOI: 10.3389/fneur.2023.1244192] [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: 06/24/2023] [Accepted: 11/03/2023] [Indexed: 12/05/2023] Open
Abstract
Background Functional restoration of hemiplegic upper limbs is a difficult area in the field of neurological rehabilitation. Electrical stimulation is one of the treatments that has shown promising advancements and functional improvements. Most of the electrical stimulations used in clinical practice are surface stimulations. In this case, we aimed to investigate the feasibility of a minimally invasive, ultrasound-guided median nerve electrical stimulation (UG-MNES) in improving the upper limb motor function and activity of a patient with right-sided hemiparesis. Case presentation A 65-year-old male recovering from a left massive intracerebral hemorrhage after open debridement hematoma removal had impaired right limb movement, right hemianesthesia, motor aphasia, dysphagia, and complete dependence on his daily living ability. After receiving 3 months of conventional rehabilitation therapy, his cognitive, speech, and swallowing significantly improved but the Brunnstrom Motor Staging (BMS) of his right upper limb and hand was at stage I-I. UG-MNES was applied on the right upper limb for four sessions, once per week, together with conventional rehabilitation. Immediate improvement in the upper limb function was observed after the first treatment. To determine the effect of UG-MNES on long-term functional recovery, assessments were conducted a week after the second and fourth intervention sessions, and motor function recovery was observed after 4-week of rehabilitation. After completing the full rehabilitation course, his BMS was at stage V-IV, the completion time of Jebsen Hand Function Test (JHFT) was shortened, and the scores of Fugl-Meyer Assessment for upper extremity (FMA-UE) and Modified Barthel Index (MBI) were increased. Overall, the motor function of the hemiplegic upper limb had significantly improved, and the right hand was the utility hand. Electromyography (EMG) and nerve conduction velocity (NCV) tests were normal before and after treatment. Conclusion The minimally invasive, UG-MNES could be a new alternative treatment in stroke rehabilitation for functional recovery of the upper limbs.
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Affiliation(s)
- Rui Li
- Department of Rehabilitation Medicine, The Second People’s Hospital of Kunming, Rehabilitation Hospital Affiliated to Kunming University, Kunming, China
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
| | - Ping Zhang
- Department of Rehabilitation Medicine, The Second People’s Hospital of Kunming, Rehabilitation Hospital Affiliated to Kunming University, Kunming, China
| | - Jingyi Lu
- Department of Rehabilitation Medicine, The Second People’s Hospital of Kunming, Rehabilitation Hospital Affiliated to Kunming University, Kunming, China
| | - Jianlin Zhuang
- Department of Rehabilitation Medicine, The Second People’s Hospital of Kunming, Rehabilitation Hospital Affiliated to Kunming University, Kunming, China
| | - Meiqi Wang
- Department of Rehabilitation Medicine, The Second People’s Hospital of Kunming, Rehabilitation Hospital Affiliated to Kunming University, Kunming, China
| | - Hongmei Fang
- Department of Rehabilitation Medicine, The Second People’s Hospital of Kunming, Rehabilitation Hospital Affiliated to Kunming University, Kunming, China
| | - Xiaowei Zhang
- Department of Rehabilitation Medicine, The Second People’s Hospital of Kunming, Rehabilitation Hospital Affiliated to Kunming University, Kunming, China
| | - Ying Gao
- Department of Rehabilitation Medicine, The Second People’s Hospital of Kunming, Rehabilitation Hospital Affiliated to Kunming University, Kunming, China
| | - Zhufen Yang
- Department of Rehabilitation Medicine, The Second People’s Hospital of Kunming, Rehabilitation Hospital Affiliated to Kunming University, Kunming, China
| | - Kai Ling Chin
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
- Borneo Medical and Health Research Centre (BMHRC), Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
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Vargas L, Musselman ED, Grill WM, Hu X. Asynchronous axonal firing patterns evoked via continuous subthreshold kilohertz stimulation. J Neural Eng 2023; 20:10.1088/1741-2552/acc20f. [PMID: 36881885 PMCID: PMC10433012 DOI: 10.1088/1741-2552/acc20f] [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: 11/19/2022] [Accepted: 03/07/2023] [Indexed: 03/09/2023]
Abstract
Objective.Transcutaneous electrical stimulation of peripheral nerves is a common technique to assist or rehabilitate impaired muscle activation. However, conventional stimulation paradigms activate nerve fibers synchronously with action potentials time-locked with stimulation pulses. Such synchronous activation limits fine control of muscle force due to synchronized force twitches. Accordingly, we developed a subthreshold high-frequency stimulation waveform with the goal of activating axons asynchronously.Approach.We evaluated our waveform experimentally and through model simulations. During the experiment, we delivered continuous subthreshold pulses at frequencies of 16.67, 12.5, or 10 kHz transcutaneously to the median and ulnar nerves. We obtained high-density electromyographic (EMG) signals and fingertip forces to quantify the axonal activation patterns. We used a conventional 30 Hz stimulation waveform and the associated voluntary muscle activation for comparison. We modeled stimulation of biophysically realistic myelinated mammalian axons using a simplified volume conductor model to solve for extracellular electric potentials. We compared the firing properties under kHz and conventional 30 Hz stimulation.Main results.EMG activity evoked by kHz stimulation showed high entropy values similar to voluntary EMG activity, indicating asynchronous axon firing activity. In contrast, we observed low entropy values in EMG evoked by conventional 30 Hz stimulation. The muscle forces evoked by kHz stimulation also showed more stable force profiles across repeated trials compared with 30 Hz stimulation. Our simulation results provide direct evidence of asynchronous firing patterns across a population of axons in response to kHz frequency stimulation, while 30 Hz stimulation elicited synchronized time-locked responses across the population.Significance.We demonstrate that the continuous subthreshold high-frequency stimulation waveform can elicit asynchronous axon firing patterns, which can lead to finer control of muscle forces.
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Affiliation(s)
- Luis Vargas
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, NC, United States of America
| | - Eric D Musselman
- Department of Biomedical Engineering, Duke University, Durham, NC, United States of America
| | - Warren M Grill
- Department of Biomedical Engineering, Duke University, Durham, NC, United States of America
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, United States of America
- Department of Neurobiology, Duke University, Durham, NC, United States of America
- Department of Neurosurgery, Duke University, Durham, NC, United States of America
| | - Xiaogang Hu
- Department of Mechanical Engineering, Pennsylvania State University, University Park, PA, United States of America
- Department of Kinesiology, Pennsylvania State University, University Park, PA, United States of America
- Department of Physical Medicine & Rehabilitation, Pennsylvania State Hershey College of Medicine, Hershey, PA, United States of America
- Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, United States of America
- Center for Neural Engineering, Pennsylvania State University, University Park, PA, United States of America
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Trout MA, Harrison AT, Brinton MR, George JA. A portable, programmable, multichannel stimulator with high compliance voltage for noninvasive neural stimulation of motor and sensory nerves in humans. Sci Rep 2023; 13:3469. [PMID: 36859464 PMCID: PMC9977866 DOI: 10.1038/s41598-023-30545-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 02/24/2023] [Indexed: 03/03/2023] Open
Abstract
Most neural stimulators do not have a high enough compliance voltage to pass current through the skin. The few stimulators that meet the high compliance voltage necessary for transcutaneous stimulation are typically large benchtop units that are not portable, and the stimulation waveforms cannot be readily customized. To address this, we present the design and validation of a portable, programmable, multichannel, noninvasive neural stimulator that can generate three custom bipolar waveforms at ± 150 V with microsecond temporal resolution. The design is low-cost, open-source, and validated on the benchtop and with a healthy population to demonstrate its functionality for sensory and motor stimulation. Sensory stimulation included electrocutaneous stimulation targeting cutaneous mechanoreceptors at the surface of the skin and transcutaneous nerve stimulation targeting the median nerve at the wrist. Both electrocutaneous stimulation on the hand and transcutaneous stimulation at the wrist can elicit isolated tactile percepts on the hand but changes in pulse frequency are more discriminable for electrocutaneous stimulation. Also, neuromuscular electrical stimulation of the flexor digiti profundus is evoked by applying electrical stimulation directly above the muscle in the forearm and to the median and ulnar nerves in the upper arm. Muscle and nerve stimulation evoked similar grip forces and force rise times, but nerve stimulation had a significantly slower fatigue rate. The development and validation of this noninvasive stimulator and direct comparison of common sensory and motor stimulation targets in a human population constitute an important step towards more widespread use and accessibility of neural stimulation for education and research.
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Affiliation(s)
- Marshall A Trout
- Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, USA.
| | - Abigail T Harrison
- Department of Biomedical Engineering, University of Utah, Salt Lake City, USA
| | - Mark R Brinton
- Department of Engineering and Physics, Elizabethtown College, Elizabethtown, USA
| | - Jacob A George
- Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, USA.
- Department of Biomedical Engineering, University of Utah, Salt Lake City, USA.
- Department of Physical Medicine and Rehabilitation, University of Utah, Salt Lake City, USA.
- Department of Mechanical Engineering, University of Utah, Salt Lake City, USA.
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Rapid Detection of Cardiac Pathologies by Neural Networks Using ECG Signals (1D) and sECG Images (3D). COMPUTATION 2022. [DOI: 10.3390/computation10070112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Usually, cardiac pathologies are detected using one-dimensional electrocardiogram signals or two-dimensional images. When working with electrocardiogram signals, they can be represented in the time and frequency domains (one-dimensional signals). However, this technique can present difficulties, such as the high cost of private health services or the time the public health system takes to refer the patient to a cardiologist. In addition, the variety of cardiac pathologies (more than 20 types) is a problem in diagnosing the disease. On the other hand, surface electrocardiography (sECG) is a little-explored technique for this diagnosis. sECGs are three-dimensional images (two dimensions in space and one in time). In this way, the signals were taken in one-dimensional format and analyzed using neural networks. Following the transformation of the one-dimensional signals to three-dimensional signals, they were analyzed in the same sense. For this research, two models based on LSTM and ResNet34 neural networks were developed, which showed high accuracy, 98.71% and 93.64%, respectively. This study aims to propose the basis for developing Decision Support Software (DSS) based on machine learning models.
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Jung J, Lee DW, Son YK, Kim BS, Shin HC. Volitional EMG Estimation Method during Functional Electrical Stimulation by Dual-Channel Surface EMGs. SENSORS 2021; 21:s21238015. [PMID: 34884015 PMCID: PMC8659961 DOI: 10.3390/s21238015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 11/19/2021] [Accepted: 11/29/2021] [Indexed: 11/24/2022]
Abstract
We propose a novel dual-channel electromyography (EMG) spatio-temporal differential (DESTD) method that can estimate volitional electromyography (vEMG) signals during time-varying functional electrical stimulation (FES). The proposed method uses two pairs of EMG signals from the same stimulated muscle to calculate the spatio-temporal difference between the signals. We performed an experimental study with five healthy participants to evaluate the vEMG signal estimation performance of the DESTD method and compare it with that of the conventional comb filter and Gram–Schmidt methods. The normalized root mean square error (NRMSE) values between the semi-simulated raw vEMG signal and vEMG signals which were estimated using the DESTD method and conventional methods, and the two-tailed t-test and analysis of variance were conducted. The results showed that under the stimulation of the gastrocnemius muscle with rapid and dynamically modulated stimulation intensity, the DESTD method had a lower NRMSE compared to the conventional methods (p < 0.01) for all stimulation intensities (maximum 5, 10, 15, and 20 mA). We demonstrated that the DESTD method could be applied to wearable EMG-controlled FES systems because it estimated vEMG signals more effectively compared to the conventional methods under dynamic FES conditions and removed unnecessary FES-induced EMG signals.
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Affiliation(s)
- Joonyoung Jung
- Electronics and Telecommunications Research Institute, Daejeon 34129, Korea
| | - Dong-Woo Lee
- Electronics and Telecommunications Research Institute, Daejeon 34129, Korea
| | - Yong Ki Son
- Electronics and Telecommunications Research Institute, Daejeon 34129, Korea
| | - Bae Sun Kim
- Electronics and Telecommunications Research Institute, Daejeon 34129, Korea
| | - Hyung Cheol Shin
- Electronics and Telecommunications Research Institute, Daejeon 34129, Korea
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Vargas L, Baratta J, Hu X. Distribution of M-Wave and H-Reflex in Hand Muscles Evoked via Transcutaneous Nerve Stimulation: A Preliminary Report. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2021; 2021:5897-5900. [PMID: 34892461 DOI: 10.1109/embc46164.2021.9630300] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Neuromuscular electrical stimulation (NMES) targeting the muscle belly is commonly used to restore muscle strength in individuals with neurological disorders. However, early onset of muscle fatigue is a major limiting factor. Transcutaneous nerve stimulation (TNS) can delay muscle fatigue compared with traditional NMES techniques. However, the recruitment of Ia afferent fibers has not be specifically targeted to maximize muscle activation through the reflex pathway, which can lead to more orderly recruitment of motor units, further delaying fatigue. This preliminary study assessed the distribution of M-wave and H-reflex of intrinsic and extrinsic finger muscles. TNS was delivered using an electrode array placed along the medial side of the upper arm. Selective electrode pairs targeted the median and ulnar nerves innervating the finger flexors. High-density electromyography (HD EMG) was utilized to quantify the spatial distribution of the elicited activation of finger intrinsic and extrinsic muscles along the hand and forearm. The spatial patterns were characterized through isolation of the M-wave and H-reflex across various stimulation levels and EMG channels. Our preliminary results showed that, by altering the stimulation amplitude, distinct M-wave and H-reflex responses were evoked across EMG channels. In addition, distinct stimulation locations appeared to result in varied levels of reflex recruitment. Our findings indicate that it is possible to adjust stimulation parameters to maximize reflex activation, which can potentially facilitate physiological recruitment order of motoneurons.
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Shin H, Hawari MA, Hu X. Activation of Superficial and Deep Finger Flexors Through Transcutaneous Nerve Stimulation. IEEE J Biomed Health Inform 2021; 25:2575-2582. [PMID: 33259310 DOI: 10.1109/jbhi.2020.3041669] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE Functional electrical stimulation (FES) is a common technique to elicit muscle contraction and help improve muscle strength. Traditional FES over the muscle belly typically only activates superficial muscle regions. In the case of hand FES, this prevents the activation of the deeper flexor muscles which control the distal finger joints. Here, we evaluated whether an alternative transcutaneous nerve-bundle stimulation approach can activate both superficial and deep extrinsic finger flexors using a high-density stimulation grid. METHODS Transverse ultrasound of the forearm muscles was used to obtain cross-sectional images of the underlying finger flexors during stimulated finger flexions and kinematically-matched voluntary motions. Finger kinematics were recorded, and an image registration method was used to capture the large deformation of the muscle regions during each flexion. This deformation was used as a surrogate measure of the contraction of muscle tissue, and the regions of expanding tissue can identify activated muscles. RESULTS The nerve-bundle stimulation elicited contractions in the superficial and deep finger flexors. Both separate and concurrent activation of these two muscles were observed. Joint kinematics of the fingers also matched the expected regions of muscle contractions. CONCLUSIONS Our results showed that the nerve-bundle stimulation technique can activate the deep extrinsic finger flexors, which are typically not accessible via traditional surface FES. SIGNIFICANCE Our nerve-bundle stimulation method enables us to produce the full range of motion of different joints necessary for various functional grasps, which could benefit future neuroprosthetic applications.
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Zheng Y, Shin H, Kamper DG, Hu X. Automatic Detection of Contracting Muscle Regions via the Deformation Field of Transverse Ultrasound Images: A Feasibility Study. Ann Biomed Eng 2020; 49:354-366. [PMID: 32632530 DOI: 10.1007/s10439-020-02557-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 06/25/2020] [Indexed: 11/28/2022]
Abstract
Accurate identification of contracting muscles can help us to understand the muscle function in both physiological and pathological conditions. Conventional electromyography (EMG) have limited access to deep muscles, crosstalk, or instability in the recordings. Accordingly, a novel framework was developed to detect contracting muscle regions based on the deformation field of transverse ultrasound images. We first estimated the muscle movements in a stepwise calculation, to derive the deformation field. We then calculated the divergence of the deformation field to locate the expanding or shrinking regions during muscle contractions. Two preliminary experiments were performed to evaluate the feasibility of the developed algorithm. Using concurrent intramuscular EMG recordings, Experiment I verified that the divergence map can capture the activity of superficial and deep muscles, when muscles were activated voluntarily or through electrical stimulation. Experiment II verified that the divergence map can only capture contracting muscles but not muscle shortening during passive movements. The results demonstrated that the divergence can individually capture the activity of muscles at different depths, and was not sensitive to muscle shortening during passive movements. The proposed framework can automatically detect the regions of contracting muscle, and could potentially serve as a tool to assess the functions of a group of muscles concurrently.
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Affiliation(s)
- Yang Zheng
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, 116 Manning Drive, 10206B Mary Ellen Jones Bldg, Chapel Hill, NC, 27599-7575, USA
| | - Henry Shin
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, 116 Manning Drive, 10206B Mary Ellen Jones Bldg, Chapel Hill, NC, 27599-7575, USA
| | - Derek G Kamper
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, 116 Manning Drive, 10206B Mary Ellen Jones Bldg, Chapel Hill, NC, 27599-7575, USA
| | - Xiaogang Hu
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, 116 Manning Drive, 10206B Mary Ellen Jones Bldg, Chapel Hill, NC, 27599-7575, USA.
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Zheng Y, Hu X. Elicited upper limb motions through transcutaneous cervical spinal cord stimulation. J Neural Eng 2020; 17:036001. [DOI: 10.1088/1741-2552/ab8f6f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Zheng Y, Hu X. Muscle activation pattern elicited through transcutaneous stimulation near the cervical spinal cord. J Neural Eng 2020; 17:016064. [DOI: 10.1088/1741-2552/ab5e09] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Shin H, Hu X. Multichannel Nerve Stimulation for Diverse Activation of Finger Flexors. IEEE Trans Neural Syst Rehabil Eng 2019; 27:2361-2368. [PMID: 31634137 DOI: 10.1109/tnsre.2019.2947785] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Neuromuscular electrical stimulation (NMES) is a common approach to restore muscle strength of individuals with a neurological injury but restoring hand dexterity is still a challenge. This study sought to quantify the diversity of finger movements elicited by a multichannel nerve stimulation technique. METHODS A 2 × 8 stimulation grid, placed on the upper arm along the ulnar and median nerves, was used to activate different finger flexors by automatically switching between randomized bipolar electrodes. The forces from each individual finger as well as the high-density electromyogram (HDEMG) of the intrinsic and extrinsic flexors were recorded. The elicited finger forces were categorized using hierarchical clustering, and the 2D correlation of the spatial patterns of muscle activation was also calculated. RESULTS A wide range of movement patterns were identified, including multi-finger and single-digit movements. Additionally, a number of electrode pairs elicited similar finger movements. The muscle activation patterns showed similar and distinct spatial patterns, signifying activation redundancy. CONCLUSION These results revealed the diversity of elicitable finger movements and muscle activations. The system redundancy can be explored to compensate for system instability due to fatigue or electrode shift. The outcomes can also enable the development of an automatic calibration of the stimulation.
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Zheng Y, Hu X. Elicited Finger and Wrist Extension Through Transcutaneous Radial Nerve Stimulation. IEEE Trans Neural Syst Rehabil Eng 2019; 27:1875-1882. [DOI: 10.1109/tnsre.2019.2930669] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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