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1.
Gene ; 766: 145157, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32949697

RESUMO

Glycolytic potential (GP) calculated based on glucose, glycogen, glucose-6-phosphate, and lactate contents is a critical factor for multiple meat quality characteristics. However, the genetic basis of glycolytic metabolism is still unclear. In this study, we constructed six RNA-Seq libraries using longissimus dorsi (LD) muscles from pigs divergent for GP phenotypic values and generated the whole genome-wide gene expression profiles. Furthermore, we identified 25,880 known and 220 novel genes from these skeletal muscle libraries, and 222 differentially expressed genes (DEGs) between the higher and lower GP groups. Notably, we found that the Lactate dehydrogenase B (LDHB) and Fructose-2, 6-biphosphatase 3 (PFKFB3) expression levels were higher in the higher GP group than the lower GP group, and positively correlated with GP and lactic acid (LA), and reversely correlated with pH value at 45 min postmortem (pH45min). Besides, LDHB and PFKFB3 expression were positively correlated with drip loss measured at 48 h postmortem (DL48h) and drip loss measured at 24 h postmortem (DL24h). Collectively, we identified a serial of DEGs as the potential key candidate genes affecting GP and found that LDHB and PFKFB3 are closely related to GP and GP-related traits. Our results lay a solid basis for in-depth studies of the regulatory mechanisms on GP and GP-related traits in pigs.


Assuntos
Glicólise/genética , Músculo Esquelético/metabolismo , Suínos/genética , Transcriptoma/genética , Animais , Perfilação da Expressão Gênica/métodos , Glucose/genética , Glicogênio/genética , Isoenzimas/genética , L-Lactato Desidrogenase/genética , Ácido Láctico/metabolismo , Carne , Fenótipo , Fosfofrutoquinase-2/genética , Suínos/metabolismo
2.
Georgian Med News ; (306): 10-18, 2020 Sep.
Artigo em Russo | MEDLINE | ID: mdl-33130638

RESUMO

Objective - to study the effect of hip contractures on the strength of the thigh muscles. Gait analysis was performed in the OpenSim 4.0 program, gait2394 was taken as the basis. Created 4 models with contractures of varying severity. We analyzed the change in the work of the thigh muscles in normal conditions, with adduction, flexion-adduction and flexion-adduction contractures with shortening. According to the data obtained in modeling the adductive and flexor-adducing contractures of the hip joint, it can be noted that contracture changes the work of the muscles around the hip joint. It was noted that modeling only adduction contracture causes noticeable changes in the medial group of femoral muscles and muscle stabilizers. Of the muscles of the posterior thigh group, m.semimembranosus, m.semitendinosus and m.biceps femoris are most susceptible to changes. These muscles change the level of load, and most importantly, periods of excitation and muscle relaxation shift. Simulation of combined flexion-adduction contracture showed that muscle dysfunctions increase, and m.sartorius, an anterior thigh muscle, was added to the muscles in which noticeable changes additionally occurred. With simulated adduction and flexion adduction contractures, changes occur in all the muscles of the thigh, periods of their excitement and relaxation shift, but the level of muscle tension is close to normal values - not exceeding them by 20-30%. Flexion-leading contracture with shortening of the limb leads to a distortion of muscle parameters in the form of excessive loads for the step (up to 100-300%). Based on the obtained simulation results, the inability of the muscles to develop the necessary efforts leads to a change in the parameters of the step in the form of a decrease in the length of the step and the duration of the periods of support on the foot, a change in the nature of the transfer of the foot. It is logical to assume that a long period of impaired muscle function will lead to the development of sustainable changes in the walking pattern.


Assuntos
Contratura , Articulação do Quadril , Quadril , Humanos , Músculo Esquelético , Coxa da Perna
3.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3771-3774, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018822

RESUMO

Muscle networks represent a series of interactions among muscles in the central nervous system's effort to reduce the redundancy of the musculoskeletal system in motor-control. How this occurs has only been investigated recently in healthy subjects with a novel technique exploring the functional connectivity between muscles through intermuscular coherence (IMC), yet the potential value of this method in characterizing the alteration of muscular networks after stroke remains unknown. In this study, muscle networks were assessed in post-stroke survivors and healthy controls to identify possible alterations in the neural oscillatory drive to muscles after stroke. Surface electromyography (sEMG) was collected from eight key upper extremity muscles to non-invasively determine the common neural input to the spinal motor neurons innervating muscle fibers. Coherence was computed between all possible muscle pairs and further decomposed by non-negative matrix factorization (NMF) to identify the common spectral patterns of coherence underlying the muscle networks. Results suggested that the number of identified muscle networks during dynamic force generation decreased after stroke. The findings in this study could provide a new prospective for understanding the motor control recovery during post-stroke rehabilitation.


Assuntos
Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral , Humanos , Músculo Esquelético , Estudos Prospectivos , Sobreviventes
4.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3775-3778, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018823

RESUMO

By 2020, over 2.2 million people in the United States will be living with an amputated lower limb. The functional impact of amputations presents significant challenges in daily living activities. While significant work has been done to develop smart prosthetics, for the long-term development of effective and robust myoelectric control systems for transtibial amputees, there is still much that needs to be understood regarding how extrinsic muscles of the lower limb are utilized post-amputation. In this study, we examined muscle activity between the intact and residual limbs of three transtibial amputees with the aim of identifying differences in voluntary recruitment patterns during a bilateral motor task. We report that while there is variability across subjects, there are consistencies in the muscle recruitment patterns for the same functional movement between the intact and the residual limb within each subject. These results provide insights for how symmetric activation in residual muscles can be characterized and used to develop myoelectric control strategies for prosthetic devices in transtibial amputees.


Assuntos
Amputados , Membros Artificiais , Tornozelo , Fenômenos Biomecânicos , Eletromiografia , Humanos , Músculo Esquelético
5.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3788-3791, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018826

RESUMO

Muscle synergistic contraction to produce force has been recognized as an important neurophysiological mechanism in neuromuscular system. Despite a range of approaches, such as nonnegative matrix factorization or principal component analysis that have been widely used, limitations still exist in analysis of dynamic coordination of multiple muscles. In addition, it is still less studied about the potential difference of muscle dynamic coordination at different force levels during grip and pinch within the same framework. With this aim, this study analyzed the dynamic coordination of multiple upper-limb muscles at low, medium and high force levels during pinch and grip with multiplex recurrence network (MRN). Twenty-four healthy subjects participated in the experiment. Subjects were instructed to grip an apparatus to match the target force as stably as they could for 10 s. Surface electromyographic (sEMG) signals were recorded from 8 upper-limb muscles and analyzed by the MRN. The interlayer mutual information (I) and the average edge overlap (ω) of MRNs were calculated to quantify muscle correlation and muscle synchronization, respectively. Results showed that I and ω values of extrinsic muscles' MRNs during grip were significantly higher than that during grip at medium and high force. Furthermore, the I and ω values of extrinsic muscle networks during grip increased with augmented force levels. No significant changes were found for the intrinsic muscles with force output levels. These findings indicate that the muscles coordination patterns between grip and pinch were different and higher co-contraction of extrinsic muscles is favorable to synergistic force production. With the force output increased, muscles' coordination was augmented in extrinsic muscles, but no change in intrinsic muscles because of independent and complicated control of fingers. This study provides an analytical tool for dynamic muscles coordination and provides insights into the mechanisms of synergistic control of muscle contractions for force production.Clinical Relevance-This study provides a novel analytical tool for muscle coordination during force production, which may facilitate the evaluation of neuromuscular function or serve as indicators for neuromuscular disorders.


Assuntos
Força da Mão , Músculo Esquelético , Eletromiografia , Dedos , Contração Muscular
6.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3965-3968, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018868

RESUMO

Recognizing human intentions from the human counterpart is very important in human-robot interaction applications. Surface electromyography(sEMG) has been considered as a potential source for motion intention because the signal represents the on-set timing and amplitude of muscle activation. It is also reported that sEMG has the advantage of knowing body movements ahead of actual movement. However, sEMG based applications suffer from electrode location variation because sEMG shows different characteristics whenever the skin condition is different. They need to recreate the estimation model if electrodes are attached to different locations or conditions. In this paper, we developed a sEMG torque estimation model for electrode location variation. A decomposition model of sEMG signals was developed to discriminate the muscle source signals for electrode location variation, and we verified this model without making a new torque estimation model. Torque estimation accuracy using the proposed method was increased by 24.8% and torque prediction accuracy was increased by 47.7% for the electrode location variation in comparison with the method without decomposition. Therefore, the proposed sEMG decomposition method showed an enhancement in torque estimation for electrode location variation.


Assuntos
Movimento , Músculo Esquelético , Eletrodos , Eletromiografia , Humanos , Torque
7.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 4130-4133, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018907

RESUMO

In recent years, high-density surface electromyography (HD-sEMG) has shown promising advantages in many robotics applications. Using HD-sEMG can not only reduce the sensitivity of the sensor position on the muscle belly but can also facilitate the acquisition of more muscle activity information due to spatial sampling. As current commercial HD-EMG systems use stationary amplifiers, leading to bulky measurements and poor portability, the interest in developing an HD-EMG sensor has increased. However, the insufficient electrode density and complicated fabrication process are challenges to overcome. In this paper, we propose a flexible HD-EMG sensor with an on-board amplifier capable of a density level of 0.53 channel/cm2, higher than those in previous works. First, we investigated the effects of different sensor parameters (i.e., the electrode material, the inter-electrode distance (IED) and the size of the electrode) on the measured signal quality. Second, a low-cost, easily fabricated, easily customized HD-EMG fabrication method was proposed based on the selected sensor parameters with a signal-to-noise ratio (SNR) comparable to those of commercial sensors. Finally, we applied a muscle activation estimation algorithm to validate the feasibility of the designed HD-EMG sensor, showing higher estimation accuracy levels. The results here demonstrate that the designed HD-EMG sensor can be used as an effective human-machine interface for robotics applications.


Assuntos
Algoritmos , Músculo Esquelético , Amplificadores Eletrônicos , Eletrodos , Eletromiografia , Humanos
8.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 176-179, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33017958

RESUMO

How to utilize and interpret microscopic motor unit (MU) activities after surface electromyogram (sEMG) decomposition towards accurate decoding of the neural control remains a great challenge. In this study, a novel framework of hybrid encoder-decoder deep networks is proposed to process the microscopic neural drive information and it is applied to precise muscle force estimation. After a high-density sEMG (HD-sEMG) decomposition was performed using the progressive FastICA peel-off algorithm, a muscle twitch force model was then applied to basically convert each channel's electric waveform (i.e., action potential) of each MU into a twitch force. Next, hybrid encoder-decoder deep networks were performed on every 50 ms of segment of the summation of twitch force trains from all decomposed MUs. The encoder network was designed to characterize spatial information of MU's force contribution over all channels, and the decoder network finally decoded the muscle force. This framework was validated on HD-sEMG recordings from the abductor pollicis brevis muscles of five subjects by a thumb abduction task using an 8 × 8 grid. The proposed framework yielded a mean root mean square error of 6.62% ± 1.26% and a mean coefficient of determination value of 0.95 ± 0.03 from a linear regression analysis between the estimated force and actual force over all data trials, and it outperformed three common methods with statistical significance (p < 0.001). This study offers a valuable solution for interpreting microscopic neural drive information and demonstrates its success in predicting muscle force.


Assuntos
Algoritmos , Músculo Esquelético , Potenciais de Ação , Sistemas Computacionais , Eletromiografia
9.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 690-693, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018081

RESUMO

The nonstationarity measure of surface Electromyography (sEMG) signals provide an index for muscle fatigue conditions. In this paper, a new framework has been proposed for the analysis of sEMG signal using Instantaneous Spectral Centroid (ISC). The novelty of the proposed work is use of topological signal processing method to quantify the nonstationarity of sEMG signal. For this, the signals are recorded from the biceps brachii muscles of 25 healthy subjects in isometric contraction. The analytical signals corresponding to nonfatigue and fatigue segments are computed using Hilbert Transform. Further, topological features such as center of gravity (CoG), triangular area function (TAF) and ISC are calculated from the geometrical representation of a transformed signal. The result indicates the increase of TAF in fatigue condition and the significant right shift of CoG in x-axis for 80% of subjects. Importantly, the ISC estimate is decreased by 17% upon fatiguing for 84% of subjects. The obtained results show statistical significance with p < 0.05. It is observed that the shape parameters are varied in accordance with the changes observed in global characteristics of sEMG signals during muscle fatigue. The preliminary results show that the topological features are able to quantify the nonstationarity in sEMG signal. Therefore, the proposed method can be used as a fatigue index for diagnosing various neuromuscular disorders.Clinical Relevance-This method can be used to establish metrics of muscle fatigue for the benefit of physicians especially in the field of fitness, sports, pre and post-surgery surveillance and rehabilitation.


Assuntos
Contração Isométrica , Fadiga Muscular , Animais , Braço , Eletromiografia , Músculo Esquelético
10.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 728-731, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018090

RESUMO

Surface electromyogram (sEMG) has been widely applied in neurorehabilitation techniques such as human-machine interface (HMI). The individual difference of sEMG characteristics has long been a challenge for multi-user HMI. However, the individually unique sEMG property indicates its high potential as a biometrics modality. In this work, we propose a novel application of high-density sEMG (HD-sEMG) for personal identification. HD-sEMG can decode the high-resolution spatial patterns of muscle activations, besides the widely studied temporal features, thus providing more sufficient information. We acquired 64-channel HD-sEMG signals on the dorsum of the right hand from 22 subjects during finger muscle isometric contractions. We achieved an accuracy of 99.5% to recognize the identity of each subject, demonstrating the excellent performance of HD-sEMG for personal identification. To the best of our knowledge, this is the first study to employ HD-sEMG for personal identification.Clinical relevance-Our work has proved the huge individual difference of HD-sEMG, which may result from the individually unique bioelectrophysiological activity of human body, deriving from both neural and biomechanical factors. The investigation of subject-specific HD-sEMG pattern may contribute to a better design of subject-specific clinical rehabilitation robots and a deeper understanding of human movement mechanism.


Assuntos
Contração Isométrica , Músculo Esquelético , Eletromiografia , Dedos , Humanos , Movimento
11.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 736-739, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018092

RESUMO

In the last decade, accurate identification of motor unit (MU) firings received a lot of research interest. Different decomposition methods have been developed, each with its advantages and disadvantages. In this study, we evaluated the capability of three different types of neural networks (NNs), namely dense NN, long short-term memory (LSTM) NN and convolutional NN, to identify MU firings from high-density surface electromyograms (HDsEMG). Each type of NN was evaluated on simulated HDsEMG signals with a known MU firing pattern and high variety of MU characteristics. Compared to dense NN, LSTM and convolutional NN yielded significantly higher precision and significantly lower miss rate of MU identification. LSTM NN demonstrated higher sensitivity to noise than convolutional NN.Clinical Relevance-MU identification from HDsEMG signals offers valuable insight into neurophysiology of motor system but requires relatively high level of expert knowledge. This study assesses the capability of self-learning artificial neural networks to cope with this problem.


Assuntos
Neurônios Motores , Músculo Esquelético , Eletromiografia , Redes Neurais de Computação
12.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 740-743, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018093

RESUMO

Modeling of surface electromyographic (EMG) signal has been proven valuable for signal interpretation and algorithm validation. However, most EMG models are currently limited to single muscle, either with numerical or analytical approaches. Here, we present a preliminary study of a subject-specific EMG model with multiple muscles. Magnetic resonance (MR) technique is used to acquire accurate cross section of the upper limb and contours of five muscle heads (biceps brachii, brachialis, lateral head, medial head, and long head of triceps brachii). The MR image is adjusted to an idealized cylindrical volume conductor model by image registration. High-density surface EMG signals are generated for two movements - elbow flexion and elbow extension. The simulated and experimental potentials were compared using activation maps. Similar activation zones were observed for each movement. These preliminary results indicate the feasibility of the multi-muscle model to generate EMG signals for complex movements, thus providing reliable data for algorithm validation.


Assuntos
Articulação do Cotovelo , Cotovelo , Eletromiografia , Movimento , Músculo Esquelético
13.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 2311-2314, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018470

RESUMO

Models of muscle contraction are typically based on a measured force-velocity relation embodied as Hill's contractile element [1]. Adopting a particular force-velocity relation dictates the muscle's mechanical properties. Dynamic crossbridge based models, such as Huxley's [2], typically focus on ultrastructural mechanics. This study adapts a dynamic lumped model of cardiac muscle contraction [3] for description of mouse soleus skeletal muscle. This compact, dynamic model exhibits the main features of skeletal muscle contraction with few assumptions. The main differences between cardiac and skeletal muscle dynamics are described. This approach gives one equation and set of parameters capable of modeling isometric and isotonic contractions, skeletal muscle's force-length relation, variations in contractility, and the force-velocity relation. This new constitutive equation may be useful for modeling striated muscle as part of larger biomechanical models.


Assuntos
Músculo Esquelético , Contração Miocárdica , Animais , Coração , Contração Isotônica , Camundongos
14.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3158-3161, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018675

RESUMO

Surface electromyography (sEMG) of the lower limb muscles has been proposed to evaluate motor dysfunctions in Parkinson's disease (PD) patients. Variability in the sEMG could be used as an indicator of poor muscle coordination, but previous studies have reported conflicting results. This study has examined the variability of muscle using the coefficients of variance of Tibialis anterior (TA) and Medial gastrocnemius (MG) lower limb muscles for 24 PD, 24 age matched controls (CO), and 24 young controls (YC), during different phases of the gait cycle. The gait intervals were measured using the inertial measurement unit (IMU). We observed a statistically significant difference between PD and control for the variability of lower limb muscle when comparing the sub-phases of the gait. It was also found that the difference was more pronounced for the TA muscle.


Assuntos
Doença de Parkinson , Caminhada , Eletromiografia , Marcha , Humanos , Músculo Esquelético
15.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3269-3272, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018702

RESUMO

Muscle synergy is a fundamental mechanism of motor control. Despite a number of studies focusing on muscle synergy during power grip and pinch at high-level force, relatively less is known about the functional interactions between muscles within low-level force production during precision pinch. Traditional analytical tools such as nonnegative matrix factorization or principal component analysis have limitations in processing nonlinear dynamic electromyographic signals and have confined sensitivity particularly for the low-level force production. In this study, we developed a novel method - multiplex muscle networks, to investigate the dynamical coordination of muscle activities at low-level force production during precision pinch. The multiplex muscle network was constructed based on multiplex limited penetrable horizontal visibility graph (MLPHVG). Seven forearm and hand muscles, including brachioradialis (BR), flexor carpi ulnaris (FCU), flexor carpi radialis (FCR), flexor digitorum superficialis (FDS), extensor digitorum communis (EDC), abductor pollicis brevis (APB) and first dorsal interosseous (FDI), were examined using surface electromyography (sEMG). Eight healthy subjects were instructed to perform a visuomotor force tracking task by producing higher (10% MVC) and lower (1% MVC) precision pinch. Interlayer mutual information I, average edge overlap ω weighted clustering coefficient CW, weighted characteristic path length LW were selected as network metrics. We assessed the undirected weighted network generated from multiplex muscle network after taking the I between paired muscle network layers as edge. There are significant differences between higher and lower force level with higher I, ω, CW and lower LW at higher force level. Advanced efficiency of information processing in the regional and global perspective indicated dynamical alterations when human faces the higher force tracking task. It suggested that ω may be an important characteristic to classify different force control states with the average classification accuracy of 82.21%. These findings reveal related alterations of functional interactions between muscles involved in precision pinch. The novel method for constructing multiplex muscle network may provide insights into muscle synergies during precision pinch force control.


Assuntos
Força da Mão , Músculo Esquelético , Eletromiografia , Antebraço , Mãos , Humanos
16.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3277-3280, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018704

RESUMO

Myoelectric prostheses are commonly controlled by surface EMG. Many control algorithms, including the user learning-based control paradigm abstract control, benefit from independent control signals. Measuring at the surface of the skin reduces the signal independence through cross talk. To increase the number of independent signals, intramuscular EMG recordings might be a viable alternative for myoelectric control. This proof of concept study investigated if real time abstract myoelectric control is possible with intramuscular measurements. Six participants performed a 4-target and 12-target abstract control task with both surface and intramuscular EMG recordings. The results suggest that intramuscular EMG is suitable for abstract control, and that performance could be increased in the future by stabilizing the amplitude of the processed intramuscular EMG signal.


Assuntos
Membros Artificiais , Músculo Esquelético , Indexação e Redação de Resumos , Eletromiografia , Humanos , Estudo de Prova de Conceito
17.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3285-3288, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018706

RESUMO

Currently, myoelectric prostheses lack dexterity and ease of control, in part because of inadequate schemes to extract relevant muscle features that can approximate muscle activation patterns that enable individuated dexterous finger motion. This project seeks to apply a novel algorithm pipeline that extracts muscle activation patterns from one limb, as well as from forearm muscles of the opposite limb, to predict muscle activation data of opposite limb intrinsic hand muscles, with the long-range goal of informing dexterous prosthetic control.


Assuntos
Desarticulação , Punho , Eletromiografia , Mãos , Músculo Esquelético
18.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3415-3419, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018737

RESUMO

Magnetomyography (MMG) is the measurement of magnetic signals generated in the skeletal muscle of humans by electrical activities. However, current technologies developed to detect such tiny magnetic field are bulky, costly and require working at the temperature-controlled environment. Developing a miniaturized, low cost and room temperature magnetic sensors provide an avenue to enhance this research field. Herein, we present an integrated tunnelling magnetoresistive (TMR) array for room temperature MMG applications. TMR sensors were developed with low-noise analogue front-end circuitry to detect the MMG signals without and with averaging at a high signal-to-noise ratio. The MMG was achieved by averaging signals using the Electromyography (EMG) signal as a trigger. Amplitudes of 200 pT and 30 pT, corresponding to periods when the hand is tense and relaxed, were observed, which is consistent with muscle simulations based on finite-element method (FEM) considering the effect of distance from the observation point to the magnetic field source.


Assuntos
Campos Magnéticos , Músculo Esquelético , Eletromiografia , Humanos , Magnetismo , Razão Sinal-Ruído
19.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3497-3500, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018757

RESUMO

The unknown composition of residual muscles surrounding the stump of an amputee makes optimal electrode placement challenging. This often causes the experimental set-up and calibration of upper-limb prostheses to be time consuming. In this work, we propose the use of existing dimensionality reduction techniques, typically used for muscle synergy analysis, to provide meaningful real-time functional information of the residual muscles during the calibration period. Two variations of principal component analysis (PCA) were applied to electromyography (EMG) data collected during a myoelectric task. Candid covariance-free incremental PCA (CCIPCA) detected task-specific muscle synergies with high accuracy using minimal amounts of data. Our findings offer a real-time solution towards optimizing calibration periods.


Assuntos
Amputados , Membros Artificiais , Eletromiografia , Humanos , Músculo Esquelético , Análise de Componente Principal
20.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3739-3742, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018814

RESUMO

The objective of this study was to quantify the differences in surface electromyogram (EMG) signal characteristics between affected and contralateral arm muscles of hemispheric stroke survivors. EMG signals were recorded from the biceps brachii muscles using single differential electrodes. Four chronic stroke subjects performed isometric elbow flexions at sub-maximal voluntary contraction levels on both the affected and contralateral limbs. The force generated on the contralateral side was matched to the force generated on the affected side. We observed different types of EMG activation on the affected side compared to the contralateral side.Specifically, two subjects showed lower RMS EMG activity on the affected side whereas two subjects showed greater EMG activity on the affected side compared to the contralateral side. Analysis of the peak amplitudes of the EMG activity showed greater number of peaks in the EMG on affected side compared to the contralateral side in all subjects. The histogram of the peak amplitudes showed greater number of smaller peak amplitudes in subjects with lower EMG activity on the affected side suggesting a reliance on smaller motor units. Our combined EMG signal analysis techniques on one set of recorded signals provides insight regarding potential mechanisms of weakness.Clinical Relevance- Decoding neural information from surface EMG signals without decomposition into individual motor units could provide clinicians with quick insight about disease progress and potential treatment.


Assuntos
Articulação do Cotovelo , Acidente Vascular Cerebral , Braço , Eletromiografia , Humanos , Músculo Esquelético
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