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Muscle synergies

Chun Kwang Tan, Hideki Kadone, Hiroki Watanabe, Aiki Marushima, Masashi Yamazaki, Yoshiyuki Sankai, Kenji Suzuki
Gait disturbance is commonly associated with stroke, which is a serious neurological disease. With current technology, various exoskeletons have been developed to provide therapy, leading to many studies evaluating the use of such exoskeletons as an intervention tool. Although these studies report improvements in patients who had undergone robotic intervention, they are usually reported with clinical assessment, which are unable to characterize how muscle activations change in patients after robotic intervention...
2018: Frontiers in Neuroscience
Michael B Jensen, Ken S Frahm, José Biurrun Manresa, Ole K Andersen
Background/aims The nociceptive withdrawal reflex (NWR) is a robust measure of nociception highly correlated with subjective pain and several studies indicate that identification of reflex thresholds may be a valuable objective tool during diagnosis of chronic pain conditions related to central sensitisation. The NWR involves complex muscle synergies but most methodologies for assessment of human withdrawal reflexes evaluates surface electromyography (sEMG) measured over just one muscle and does not consider the possible interference of crosstalk from adjacent muscles...
December 29, 2017: Scandinavian Journal of Pain
Gustavo Balbinot, Clarissa Pedrini Schuch, Matthew S Jeffers, Matthew W McDonald, Jessica M Livingston-Thomas, Dale Corbett
A coordinated pattern of multi-muscle activation is essential to produce efficient reaching trajectories. Disruption of these coordinated activation patterns, termed synergies, is evident following stroke and results in reaching deficits; however, preclinical investigation of this phenomenon has been largely ignored. Furthermore, traditional outcome measures of post-stroke performance seldom distinguish between impairment restitution and compensatory movement strategies. We sought to address this by using kinematic analysis to characterize reaching movements and kinematic synergies of rats performing the Montoya staircase task, before and after ischemic stroke...
June 7, 2018: Scientific Reports
F A Jure, F G Arguissain, J A Biurrun Manresa, O K Andersen
Aims Conditioned pain modulation (CPM) is a paradigm employed to assess descending control of spinal nociception. Previous studies have shown that CPM affects the nociceptive withdrawal reflex (NWR) threshold (RTh), typically assessed in one muscle. However, the NWR activates not one but a group of synergistic muscles, which are recruited by common neural commands to achieve the limb withdrawal. In this regard, synergy analysis can provide the minimum coordinated recruitment of groups of muscles with specific activation balances that describe a movement...
December 29, 2017: Scandinavian Journal of Pain
Rajat Emanuel Singh, Kamran Iqbal, Gannon White, Tarun Edgar Hutchinson
The central nervous system (CNS) is believed to utilize specific predefined modules, called muscle synergies (MS), to accomplish a motor task. Yet questions persist about how the CNS combines these primitives in different ways to suit the task conditions. The MS hypothesis has been a subject of debate as to whether they originate from neural origins or nonneural constraints. In this review article, we present three aspects related to the MS hypothesis: (1) the experimental and computational evidence in support of the existence of MS, (2) algorithmic approaches for extracting them from surface electromyography (EMG) signals, and (3) the possible role of MS as a neurorehabilitation tool...
2018: Applied Bionics and Biomechanics
Ioannis Delis, Pauline M Hilt, Thierry Pozzo, Stefano Panzeri, Bastien Berret
Voluntary movement is hypothesized to rely on a limited number of muscle synergies, the recruitment of which translates task goals into effective muscle activity. In this study, we investigated how to analytically characterize the functional role of different types of muscle synergies in task performance. To this end, we recorded a comprehensive dataset of muscle activity during a variety of whole-body pointing movements. We decomposed the electromyographic (EMG) signals using a space-by-time modularity model which encompasses the main types of synergies...
May 30, 2018: Scientific Reports
Juri Taborri, Valentina Agostini, Panagiotis K Artemiadis, Marco Ghislieri, Daniel A Jacobs, Jinsook Roh, Stefano Rossi
In the last years, several studies have been focused on understanding how the central nervous system controls muscles to perform a specific motor task. Although it still remains an open question, muscle synergies have come to be an appealing theory to explain the modular organization of the central nervous system. Even though the neural encoding of muscle synergies remains controversial, a large number of papers demonstrated that muscle synergies are robust across different tested conditions, which are within a day, between days, within a single subject, and between subjects that have similar demographic characteristics...
2018: Applied Bionics and Biomechanics
Michele Vitacca, Mara Paneroni
Chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF) frequently coexist, significantly reducing the patient's quality of life (QoL) and increasing morbidity, disability and mortality. For both diseases, a multidisciplinary disease-management approach offers the best outcomes and reduces hospital readmissions. In both conditions, muscle dysfunction may dramatically influence symptoms, exercise tolerance/performance, health status and healthcare costs. The present review describes muscular abnormalities and mechanisms underlying these alterations...
May 25, 2018: COPD
Anton Popov, Erienne V Olesh, Sergiy Yakovenko, Valeriya Gritsenko
This study reports a new technique for extracting muscle synergies using continuous wavelet transform. The method allows to quantify coincident activation of muscle groups caused by the physiological processes of fixed duration, thus enabling the extraction of wavelet modules of arbitrary groups of muscles. Hierarchical clustering and identification of the repeating wavelet modules across subjects and across movements, was used to identify consistent muscle synergies. Results indicate that the most frequently repeated wavelet modules comprised combinations of two muscles that are not traditional agonists and span different joints...
March 2018: ... International Conference on Wearable and Implantable Body Sensor Networks
Ahmed Ebied, Eli Kinney-Lang, Loukianos Spyrou, Javier Escudero
The muscle synergy concept provides a widely-accepted paradigm to break down the complexity of motor control. In order to identify the synergies, different matrix factorisation techniques have been used in a repertoire of fields such as prosthesis control and biomechanical and clinical studies. However, the relevance of these matrix factorisation techniques is still open for discussion since there is no ground truth for the underlying synergies. Here, we evaluate factorisation techniques and investigate the factors that affect the quality of estimated synergies...
July 2018: Medical Engineering & Physics
Naji A Alibeji, Vahidreza Molazadeh, Brad E Dicianno, Nitin Sharma
A hybrid walking neuroprosthesis that combines functional electrical stimulation (FES) with a powered lower limb exoskeleton can be used to restore walking in persons with paraplegia. It provides therapeutic benefits of FES and torque reliability of the powered exoskeleton. Moreover, by harnessing metabolic power of muscles via FES, the hybrid combination has a potential to lower power consumption and reduce actuator size in the powered exoskeleton. Its control design, however, must overcome the challenges of actuator redundancy due to the combined use of FES and electric motor...
2018: Frontiers in Neuroscience
Paola Mantuano, Francesca Sanarica, Elena Conte, Maria Grazia Morgese, Roberta Francesca Capogrosso, Anna Cozzoli, Adriano Fonzino, Angelo Quaranta, Jean-Francois Rolland, Michela De Bellis, Giulia Maria Camerino, Luigia Trabace, Annamaria De Luca
The pharmacological stimulation of AMP-activated protein kinase (AMPK) via metabolic enhancers has been proposed as potential therapeutic strategy for Duchenne muscular dystrophy (DMD). Metformin, a widely-prescribed anti-hyperglycemic drug which activates AMPK via mitochondrial respiratory chain, has been recently tested in DMD patients in synergy with nitric oxide (NO)-precursors, with encouraging results. However, preclinical data supporting the use of metformin in DMD are still poor, and its actions on skeletal muscle appear controversial...
April 21, 2018: Biochemical Pharmacology
Benjamin R Shuman, Marije Goudriaan, Kaat Desloovere, Michael H Schwartz, Katherine M Steele
OBJECTIVE: To determine whether patient-specific differences in motor control quantified using muscle synergy analysis were associated with changes in gait after treatment of cerebral palsy (CP) across 2 clinical centers with different treatments and clinical protocols. DESIGN: Retrospective cohort study. SETTING: Clinical medical center. PARTICIPANTS: Center 1: children with CP (n=473) and typically developing (TD) children (n=84)...
April 10, 2018: Archives of Physical Medicine and Rehabilitation
Luigino Calzetta, Maria Gabriella Matera, Mario Cazzola
Long-acting β2 adrenoceptor agonists (LABAs) in combination with long-acting muscarinic antagonists (LAMAs) can elicit functional and clinical benefits in chronic obstructive pulmonary disease (COPD). LABA/LAMA combinations synergistically relax human isolated airways at the level of the medium and small bronchi. LABAs and LAMAs both modulate the bronchial tone via different pathways localized at the level of presynaptic parasympathetic fibers and airway smooth muscle cells. The exact nature of the interactions between these pathways is not completely understood, but there is cross-talk at many levels in airway smooth muscle cells that is also regulated by the activity of calcium-activated potassium channels and protein tyrosine kinases...
April 4, 2018: Current Opinion in Pharmacology
Kyuengbo Min, Duk Shin, Jongho Lee, Shinji Kakei
Electromyogram signal (EMG) measurement frequently experiences uncertainty attributed to issues caused by technical constraints such as cross talk and maximum voluntary contraction. Due to these problems, individual EMGs exhibit uncertainty in representing their corresponding muscle activations. To regulate this uncertainty, we proposed an EMG refinement, which refines EMGs with regulating the contribution redundancy of the signals from EMGs to approximating torques through EMG-driven torque estimation (EDTE) using the muscular skeletal forward dynamic model...
April 27, 2018: Journal of Biomechanics
Kun Liu, Yong Liu, Jianchao Yan, Zhenyuan Sun
Partial body weight support or loading sit-to-stand (STS) rehabilitation can be useful for persons with lower limb dysfunction to achieve movement again based on the internal residual muscle force and external assistance. To explicate how the muscles contribute to the kinetics and kinematics of STS performance by non-invasive in vitro detection and to nondestructively estimate the muscle contributions to STS training with different loadings, a wearable sensor system was developed with ground reaction force (GRF) platforms, motion capture inertial sensors and electromyography (EMG) sensors...
March 25, 2018: Sensors
Ali Falaki, Hang Jin Jo, Mechelle M Lewis, Barbara O'Connell, Sol De Jesus, James McInerney, Xuemei Huang, Mark L Latash
OBJECTIVE: We explored effects of deep brain stimulation (DBS) in patients with Parkinson's disease (PD) on the synergic control of fingers in a multi-finger force production task and of muscles in a task involving vertical posture. METHODS: The finger task involved the four fingers of a hand producing accurate total force followed by a targeted quick force pulse. The postural task involved releasing a load from extended arms. The analysis of synergies was performed within the framework of the uncontrolled manifold hypothesis...
June 2018: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
Momoko Yamagata, Ali Falaki, Mark L Latash
We explored the relations between indices of mechanical stability of vertical posture and synergy indices under unexpected perturbations. The main hypotheses predicted higher posture-stabilizing synergy indices and higher mechanical indices of center of pressure stability during perturbations perceived by subjects as less challenging. Healthy subjects stood on a force platform and held in fully extended arms a bar attached to two loads acting downward and upward. One of the loads was unexpectedly released by the experimenter causing a postural perturbations...
May 2018: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
Cristian Cuadra, Angelo Bartsch, Paula Tiemann, Sasha Reschechtko, Mark L Latash
We explored whether the synergic control of the hand during multi-finger force production tasks depends on the hand muscles involved. Healthy subjects performed accurate force production tasks and targeted force pulses while pressing against loops positioned at the level of fingertips, middle phalanges, and proximal phalanges. This varied the involvement of the extrinsic and intrinsic finger flexors. The framework of the uncontrolled manifold (UCM) hypothesis was used to analyze the structure of inter-trial variance, motor equivalence, and anticipatory synergy adjustments prior to the force pulse in the spaces of finger forces and finger modes (hypothetical finger-specific control signals)...
May 2018: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
Sharon Israely, Gerry Leisman, Chay C Machluf, Eli Carmeli
Purpose: A muscle synergies model was suggested to represent a simplifying motor control mechanism by the brainstem and spinal cord. The aim of the study was to investigate the feasibility of such control mechanisms in the rehabilitation of post-stroke individuals during the execution of hand-reaching movements in multiple directions, compared to non-stroke individuals. Methods: Twelve non-stroke and 13 post-stroke individuals participated in the study. Muscle synergies were extracted from EMG data that was recorded during hand reaching tasks, using the NMF algorithm...
2018: Frontiers in Computational Neuroscience
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