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Boyd, William J. "EMG Site: A MATLAB-based Application for EMG Data Collection and EMG-based Prosthetic Control." Digital WPI, 2018. https://digitalcommons.wpi.edu/etd-theses/351.
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This thesis describes the system design of EMG Site, a MATLAB-based application for collection and visualization of surface electromyograms (EMGs) and the real-time control of an upper limb prosthesis, including details pertaining to the design of the software and the graphical user interface (GUI). The application consists of features that aid in the visualization of the collected EMG data and the control of a prosthesis. Visualization of the collected EMG data is handled in one of two ways: an oscilloscope-like view showing the raw EMG data collected with respect to time, or a radial plot showing the processed EMG data collected with respect to the site of EMG data collection on the arm. The control of a hand-wrist prosthesis is primarily regulated through the use of signal processing designed to relate EMG to torque and is visualized in the tracking window - a plotting window showing both a user-control cursor and an either static (or dynamic) computer-controlled target. This thesis concludes with a description of the real-time capabilities of the application regarding both the visualization of the collected EMG data as well as the control of a prosthesis.
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Wang, Jing M. Eng Massachusetts Institute of Technology. "EMG control of prosthetic ankle plantar flexion." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/76110.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Biological Engineering, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 59-60).
Similar to biological human ankle, today's commercially available powered ankle-foot prostheses can vary impedance and deliver net positive ankle work. These commercially available prostheses are intrinsically controlled. Users cannot intuitively change ankle controller's behavior to perform movements that are not part of the repetitive walking gait cycle. For example, when transition from level ground walking to descending stairs, user cannot intuitively initiate or control the amount of ankle angle deflexion for a more normative stair descent gait pattern. This paper presents a hybrid controller that adds myoelectric control functionality to an existing intrinsic controller. The system employs input from both mechanical sensors on the ankle as well as myoelectric signals from gastrocnemius muscle of the user. This control scheme lets the user to modulate the gain of command ankle torque upon push off during level ground walking and stair ascent. It also allows the user to interrupt level ground walking control cycle and initiate ankle plantar flexion during stair descent. As a preliminary study, ankle characteristics such as ankle angle and torque were measured and compared to biological ankle characteristics. Results show that the proposed hybrid controller can maintain existing controller's biomimetic characteristics. In addition, it can also recognize to a qualitative extent the intended command torque for ankle push off and user's desire to switch between control modalities for different terrains. The study shows that it is possible and desirable to use neural signals as control signals for prosthetic leg controllers. Keyword: Myoelectric control, powered prosthesis, proportional torque control
by Jing Wang.
M.Eng.
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Baccherini, Simona. "Pattern recognition methods for EMG prosthetic control." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/12033/.
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In this work we focus on pattern recognition methods related to EMG upper-limb prosthetic control. After giving a detailed review of the most widely used classification methods, we propose a new classification approach. It comes as a result of comparison in the Fourier analysis between able-bodied and trans-radial amputee subjects. We thus suggest a different classification method which considers each surface electrodes contribute separately, together with five time domain features, obtaining an average classification accuracy equals to 75% on a sample of trans-radial amputees. We propose an automatic feature selection procedure as a minimization problem in order to improve the method and its robustness.
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Peña, Guido Gómez. "Controle de impedância adaptativo dirigido por EMG para reabilitacão robótica." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/18/18149/tde-19032019-144320/.
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Esta tese trata da estimativa de torque e rigidez do paciente dirigida por EMG e sua utilização para adaptar a rigidez do robô durante a reabilitação assistida por robôs. Os sinais eletromiográficos (EMG), obtidos de músculos que atuam durante os movimentos de flexão e extensão de um usuário utilizando uma órtese de joelho ativa, são processados para obter as ativações dos músculos. Inicialmente, um modelo musculoesquelético simplificado e otimizado é usado para calcular as estimativas de torque e rigidez da junta do paciente. A otimização do modelo é realizada comparando o torque estimado com o torque gerado pela ferramenta de dinâmica inversa do software OpenSim, considerando um modelo musculoesquelético escalonado. Como uma solução complementar, é proposta uma rede neural perceptron multicamada (NN) para mapear os sinais EMG para o torque do paciente. Também é apresentado um Ambiente de Estimativa de Torque Gerado por EMG criado para analisar os dados obtidos a partir da aplicação das abordagens propostas considerando a aplicação de um protocolo criado para a análise de interação usuário-exoesqueleto. Um banco de dados de indivíduos saudáveis também foi disponibilizado neste trabalho. Além disso, uma estratégia de controle de impedância adaptativa é proposta para ajustar a rigidez do robô com base na estimativa de rigidez do paciente por EMG. A estratégia inclui uma solução ideal para a interação paciente-robô. Finalmente, são apresentados os resultados obtidos aplicando o controle de impedância adaptativo proposto durante os movimentos de flexão e extensão do usuário que usa a órtese ativa.This thesis deals with EMG-driven patient torque and stiffness estimation and its use to adapt the robot stiffness during robot-aided rehabilitation. Electromyographic (EMG) signals, taken from selected muscles acting during flexion and extension movements of an user wearing an active knee orthosis, are processed to get the muscles activations. First, a simplified and optimized musculoskeletal model is used to compute the estimate of patient joint torque and stiffness. The model optimization is performed by comparing the estimate torque with the torque generated by the inverse dynamics tool of the OpenSim software, considering a scaled musculoskeletal model. As a complementary solution, a multilayer perceptron neural network (NN) is proposed to map the EMG signals to the patient torque. It is also presented an EMG-driven Torque Estimation Environment created to analyze the data obtained from the application of the proposed approaches considering a protocol created for user-exoskeleton interaction analysis. A database with data from 5 healthy subjects is also made available in this work. Additionally, an adaptive impedance control strategy is proposed to adjust the robot stiffness based on the EMG-driven patient stiffness estimation. The strategy includes an optimal solution for the patient-robot interaction. Finally, the results obtained by applying the proposed adaptive impedance control during flexion and extension movements of the user wearing the active orthosis are presented.
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Grisetto, Fanny. "Impulsivity is not just disinhibition : investigating the effects of impulsivity on the adaptation of cognitive control mechanisms." Thesis, Lille 3, 2020. http://www.theses.fr/2020LIL3H031.
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L’impulsivité est une tendance comportementale fréquemment observée dans la population générale mais à des degrés différents. À ce propos, une forte impulsivité augmente les risques de développer un trouble psychiatrique, tel que les différentes formes d’addiction ou des troubles de la personnalité. Pour comprendre l’émergence de ces divers troubles comportementaux, mon projet de thèse s’est porté sur le rôle du contrôle cognitif dans les manifestations de l’impulsivité. Le contrôle cognitif est, en effet, un ensemble de fonctions cognitives nous permettant d’adapter nos comportements à un environnement changeant, et donc complexe. Durant ma thèse, je me suis plus particulièrement intéressée aux capacités d’adaptation des mécanismes de contrôle proactif et réactif chez des individus impulsifs, principalement dans la population générale mais également auprès de patients alcoolo-dépendants.Les trois premières études de ma thèse ont montré qu’une forte impulsivité était caractérisée par une utilisation moindre des mécanismes proactifs associée à un défaut d’adaptation des mécanismes de contrôle aux demandes externes et aux contraintes internes.Les individus impulsifs exercent moins de contrôle proactif alors que celui-ci devrait être favorisé au vu des caractéristiques contextuelles ou individuelles. Dans une quatrième étude dans laquelle des enregistrements EEG ont été effectués, nous nous sommes intéressées à l’activité cérébrale typique observée au moment de l’exécution des erreurs,nommée ERN/Ne, et dont le rôle serait de signaler les besoins en contrôle. Une réduction de cette activité cérébrale a été observée chez les individus les plus agressifs, mais pas chez les individus les plus impulsifs. Ce résultat suggère que l’émergence de comportements inadaptés pourrait être en partie expliquée par cette réduction du signal d’alarme. Enfin,des résultats préliminaires suggèrent un lien entre un indice périphérique de l’adaptation physiologique (HRV) et les capacités d’adaptation des mécanismes de contrôle. Ce résultat ouvre la voie à de nouvelles interventions thérapeutiques pour la réduction des comportements inadaptés.Dans l’ensemble, les résultats de cette thèse suggèrent que l’impulsivité en population générale est associée à un système de contrôle cognitif moins proactif et moins flexible,menant potentiellement à des comportements inappropriés quand les mécanismes de contrôle en jeu sont inadaptésImpulsivity is a behavioral tendency frequently observed in the general population butat different degrees. Interestingly, higher impulsivity increases the probability to develop and to be diagnosed with a psychiatric disorder, such as substance use or personality disorders. To gain a better understanding on the emergence of such psychiatric disorders, my PhD project focused on the role of cognitive control in impulsive manifestations. Indeed, cognitive control is a set of basic executive functions ensuring adaptive behaviors to an ever-changing and complex environment. More particularly, during my PhD research, I investigated the flexible adaptation between reactive and proactive control mechanisms in impulsive individuals, mainly from the general population but also from an alcohol-dependent population.The first three studies of my thesis revealed that high impulsivity was characterizedby a less-proactive cognitive control system, and associated with a weaker adaptation ofcognitive control mechanisms both to external demands and internal constraints. Morespecifically, I observed that high impulsive individuals less exert proactive control whileit should be favored given contextual or individual characteristics. In the fourth study inwhich EEG signals were recorded, we were interested in the brain activity that is typicallyobserved during errors (i.e., the ERN/Ne), which is thought to signal the need for control.A reduction in this brain activity was observed in high aggressive individuals, but notin high impulsive individuals. This finding suggest that the emergence of maladaptivebehaviors may be explained, to a certain extent, by the reduced alarm signal. Finally, somepreliminary results suggest a link between a peripheral index of physiological adaptation(i.e., HRV) and the capacity to adapt control mechanisms. These findings open newavenues for therapeutic interventions in the reduction in maladaptive behaviors.Overall, findings from the current thesis suggest that impulsivity in the general population is associated with a less proactive and a less flexible cognitive control system, potentially leading to inappropriate behaviors when the control mechanisms at play are maladapted
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Ammendrup, Katrin. "Framework for Wireless Acquisition of Surface EMG and Real-Time Control." Thesis, KTH, Medicinteknik och hälsosystem, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-233311.
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Muscle driven devices are controlled or powered with muscle activation. These devices open up the possibility of offering patients with limited muscle function to automatically control assistive devices - for instance exoskeletons - with input from their own muscles. This solution would help a number of patient groups suffering from common conditions, such as spinal cord injuries, stroke and cerebral palsy. To use muscle activation as input it is necessary to have a way to communicate with the mus- cles. Electromyography (EMG) is a technology used to gain information about muscle function and activation. It is performed by measuring and analyzing electrical signals conducted by the muscles during activation. Activation and activation level can be seen from analyzed EMG signal. EMG signals are frequently measured and analyzed afterwards, however, to use it as a controlling an assistive devices, real time analysis is necessary. In this thesis real time acquisi- tion and analysis of EMG was performed. The measured signal was used as an input to control a simple MATLAB computer game. The EMG of a muscle of the forearm, Brachioradialis, was measured with Myon Aktos sys- tem. The measured signal was written to a server as soon as the measurements were acquired. MATLAB was used to connect to the server and performing the signal analysis. The analysis was kept simple in order to limit delay. The result showed that it was possible to acquire real time signal with this method. The delay was negligible, both for the testing and for the game play. Showing that it is possible to play a game with muscle activation supports the idea of a motor that can be controlled automatically with muscle input. Future work should focus on understanding movement intent with respect to EMG and on analyzing multiple signals from different muscles at the same time.
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Laine, Christopher. "Decoding the Language of Hypoglossal Motor Control." Diss., The University of Arizona, 2011. http://hdl.handle.net/10150/203440.
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To effect movement, the central nervous system must appropriately coordinate the activities of pools of motoneurons (MNs), the cells which control muscle fibers. Sources of neural drive are often distributed to many MNs of a pool, and thus can synchronize the activities of targeted MNs. In this thesis, synchronization among MNs is used to investigate the strength, temporal progression, and anatomical distribution of neural drive to the hypoglossal motor nucleus (HMN), which controls muscles of the tongue. The HMN is an ideal target for such an investigation because it processes a host of functionally diverse inputs, such as those related to breathing, speaking, and swallowing. Study 1 characterizes motor unit (MU) synchronization within and across bellies of the human genioglossus (GG) muscle when MUs are activated by cortical drive (during voluntary tongue protrusion) or by automatic, brainstem-mediated drive (during rest breathing). We show that voluntary tongue protrusion synchronizes MU spike timing and firing rates within but not across bellies of the GG, whereas during rest breathing, MU firing rates are moderately synchronized both within and across muscle bellies. Study 2 documents respiratory-related synchronization of MU activities in muscles of the tongue and respiratory pump using an anesthetized rat model. The results of this study indicate that upper airway and respiratory pump MN pools share a low frequency respiratory-related drive, but that higher frequency (>8 Hz) synchronization is strongest in MU pairs of the chest-wall. Finally, Study 3 examines the potential for GG multi-unit and single MU activities to be entrained by cortical input. We show that during voluntary tongue protrusion, cortical oscillations in the 15-40 Hz range weakly synchronize MU population activity, and that EEG oscillations in this range intermittently influence the spike timing of individual GG MUs. These studies are the first to characterize MU synchronization by different sources of neural input to the HMN and establish a broad foundation for further investigation of hypoglossal motor control.
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Tarullo, Viviana. "Artificial Neural Networks for classification of EMG data in hand myoelectric control." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/19195/.
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This thesis studies the state-of-the-art in myoelectric control of active hand prostheses for people with trans-radial amputation using pattern recognition and machine learning techniques. Our work is supported by Centro Protesi INAIL in Vigorso di Budrio (BO). We studied the control system developed by INAIL consisting in acquiring EMG signals from amputee subjects and using pattern recognition methods for the classifcation of acquired signals, associating them with specifc gestures and consequently commanding the prosthesis. Our work consisted in improving classifcation methods used in the learning phase. In particular, we proposed a classifer based on a neural network as a valid alternative to the INAIL one-versus-all approach to multiclass classifcation.
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Simkin, Laurey R. "The effects of performance feedback and EMG biofeedback contingency on self-perceptions." Scholarly Commons, 1986. https://scholarlycommons.pacific.edu/uop_etds/2123.
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Källman, Alexandra, and Nina Nylander. "Läppasymmetrier hos stammande och icke-stammande personer : En EMG-studie." Thesis, Uppsala universitet, Logopedi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-242637.
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Det har tidigare rapporterats att icke-stammande personer har en tydlig vänstersidig cerebral lateralisering vad gäller talmotoriken, vilket visas genom ökad högersidig aktivering i läppmuskulaturen. Personer med stamning har å andra sidan föreslagits ha ett vänstersidigt eller bilateralt aktiveringsmönster av talmuskulaturen. Detta antas vara en av orsakerna till stamning. Testdeltagarna i aktuell studie bestod av 11 stammande och 13 matchade icke-stammande vuxna. Uppgifterna bestod av ordrepetition, ordgenerering samt att puta med läpparna. EMG-aktivitet från musklerna orbicularis oris och depressor labii inferior registrerades med elektroder på höger och vänster sida av läppmuskulaturen. Syftet med aktuell studie var att undersöka eventuell skillnad i läppasymmetri mellan stammande och icke-stammande vuxna personer. Resultatet kunde inte påvisa signifikanta gruppskillnader i grad av muskelaktivering för läppmuskulaturen. Båda grupperna uppvisade tvärtemot förväntan en nästintill bilateral aktivitet. En tendens till positiv korrelation, om än inte statistiskt signifikant, kunde observeras mellan grad av uppvisad stamning och något mer högersidig muskelaktivering.
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Ali, Ali Hussein. "An investigation of electromyographic (EMG) control of dextrous hand prostheses for transradial amputees." Thesis, University of Plymouth, 2013. http://hdl.handle.net/10026.1/2860.
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There are many amputees around the world who have lost a limb through conflict, disease or an accident. Upper-limb prostheses controlled using surface Electromyography (sEMG) offer a solution to help the amputees; however, their functionality is limited by the small number of movements they can perform and their slow reaction times. Pattern recognition (PR)-based EMG control has been proposed to improve the functional performance of prostheses. It is a very promising approach, offering intuitive control, fast reaction times and the ability to control a large number of degrees of freedom (DOF). However, prostheses controlled with PR systems are not available for everyday use by amputees, because there are many major challenges and practical problems that need to be addressed before clinical implementation is possible. These include lack of individual finger control, an impractically large number of EMG electrodes, and the lack of deployment protocols for EMG electrodes site selection and movement optimisation. Moreover, the inability of PR systems to handle multiple forces is a further practical problem that needs to be addressed. The main aim of this project is to investigate the research challenges mentioned above via non-invasive EMG signal acquisition, and to propose practical solutions to help amputees. In a series of experiments, the PR systems presented here were tested with EMG signals acquired from seven transradial amputees, which is unique to this project. Previous studies have been conducted using non-amputees. In this work, the challenges described are addressed and a new protocol is proposed that delivers a fast clinical deployment of multi-functional upper limb prostheses controlled by PR systems. Controlling finger movement is a step towards the restoration of lost human capabilities, and is psychologically important, as well as physically. A central thread running through this work is the assertion that no two amputees are the same, each suffering different injuries and retaining differing nerve and muscle structures. This work is very much about individualised healthcare, and aims to provide the best possible solution for each affected individual on a case-by-case basis. Therefore, the approach has been to optimise the solution (in terms of function and reliability) for each individual, as opposed to developing a generic solution, where performance is optimised against a test population. This work is unique, in that it contributes to improving the quality of life for each individual amputee by optimising function and reliability. The main four contributions of the thesis are as follows: 1- Individual finger control was achieved with high accuracy for a large number of finger movements, using six optimally placed sEMG channels. This was validated on EMG signals for ten non-amputee and six amputee subjects. Thumb movements were classified successfully with high accuracy for the first time. The outcome of this investigation will help to add more movements to the prosthesis, and reduce hardware and computational complexity. 2- A new subject-specific protocol for sEMG site selection and reliable movement subset optimisation, based on the amputee’s needs, has been proposed and validated on seven amputees. This protocol will help clinicians to perform an efficient and fast deployment of prostheses, by finding the optimal number and locations of EMG channels. It will also find a reliable subset of movements that can be achieved with high performance. 3- The relationship between the force of contraction and the statistics of EMG signals has been investigated, utilising an experimental design where visual feedback from a Myoelectric Control Interface (MCI) helped the participants to produce the correct level of force. Kurtosis values were found to decrease monotonically when the contraction level increased, thus indicating that kurtosis can be used to distinguish different forces of contractions. 4- The real practical problem of the degradation of classification performance as a result of the variation of force levels during daily use of the prosthesis has been investigated, and solved by proposing a training approach and the use of a robust feature extraction method, based on the spectrum. The recommendations of this investigation improve the practical robustness of prostheses controlled with PR systems and progress a step further towards clinical implementation and improving the quality of life of amputees. The project showed that PR systems achieved a reliable performance for a large number of amputees, taking into account real life issues such as individual finger control for high dexterity, the effect of force level variation, and optimisation of the movements and EMG channels for each individual amputee. The findings of this thesis showed that the PR systems need to be appropriately tuned before usage, such as training with multiple forces to help to reduce the effect of force variation, aiming to improve practical robustness, and also finding the optimal EMG channel for each amputee, to improve the PR system’s performance. The outcome of this research enables the implementation of PR systems in real prostheses that can be used by amputees.
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Lockhart, Daniel Bruce. "Prediction of Muscle Activation Patterns During Postural Control Using a Feedback Control Model." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7280.
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Neural mechanisms determining temporal muscle activity patterns during postural control are not well understood. We hypothesize that a feedback control mechanism can predict both temporal extensor muscle EMG and CoM kinematics (acceleration, velocity, and displacement) during postural perturbations before and following peripheral neuropathy to group I afferents induced by pyridoxine intoxication. We introduce a feedback model for analyzing temporal EMG patterns that decomposes recorded electromyogram (EMG) signals into the sum of three center of mass (CoM) feedback components. EMG and CoM kinematics during postural responses due to support surface translations were measured before and 14 days after somatosensory loss in cats. We successfully predicted EMG before and after peripheral neuropathy by modeling a standing cat as an inverted pendulum and decomposing temporal EMG patterns using a simulation with time delayed feedback loop of CoM kinematics. This model accounts for over 60% of the total temporal variability of recorded extensor EMG patterns. Feedback gains for acceleration, velocity and position necessary to predict EMGs before and after sensory loss were different. For intact animals, more that 90% of the initial burst of EMG were due to CoM acceleration feedback, while later portions were due entirely to velocity and position feedback. After peripheral neuropathy, the initial burst was absent and the acceleration gain was significantly reduced when compared to the acceleration gain of intact animals for extensor muscles (p lt 0.05). By successfully decomposing EMG into three kinematic gains, a quantitative comparison of temporal EMG patterns before and after peripheral neuropathy is possible. The reduction of acceleration gain in sensory loss cats suggests that group I afferents provide necessary information that is used as acceleration feedback.
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Hincapie, Juan Gabriel. "EMG-Based Control of Upper Extremity Neuroprostheses for C5/C6 Spinal Cord Injury." Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1212766320.
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Killikelly, Clare. "Dynamic psychophysiological change in cognitive control across the adult lifespan : ERP and EMG studies." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607697.
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Giuffrida, Joseph P. "Synergistic Neural Network Control of FES Elbow Extension After Spinal Cord Injury Using EMG." Case Western Reserve University School of Graduate Studies / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=case1081513453.
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Grier, Finlay. "The Reduction of Tension Headache Using EMG Biofeedback and Locus of Control as Predictors." Thesis, University of North Texas, 1989. https://digital.library.unt.edu/ark:/67531/metadc332051/.
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This study investigates the status of biofeedback treatment and locus of control (LOC) affiliation on the reduction of tension headache. Three LOC groups designated as internals, powerful-other externals and chance externals (using Wallston and Wallston's, 1978, Multidimensional Health Locus of Control Scale) were administered an eight week electromyogram (EMG) frontalis muscle biofeedback training program using an Autogen 1700 biofeedback unit. Subjects were 12 female and four male undergraduate students who had a history of tension headache. Results indicated no significant difference in frontalis muscle tension between the beginning and end of sessions in either a biofeedback or self-control condition for any of the LOC groups. Further, there was no significant difference among LOC groups in ability to reduce muscle tension in either the training or self-control condition. Finally, neither biofeedback training nor LOC groups were significant predictors of headache reduction. Extreme within-group variability and small sample size affected study findings and these and other implications for future research are discussed.
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Mavritsaki, Eirini. "Motoneural control of the nictitating membrane response in classical conditioning : a modelling and EMG study." Thesis, University of Sheffield, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.420705.
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Mulcahy, Elaine. "An identification of task dependent frequency characteristics in normal and amputee EEG and EMG for use in intention detection for neuroprosthetic control." Thesis, University of Strathclyde, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367078.
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Hewitt, G. "A study of developmental and intersubject differences in the use of EMG biofeedback to improve voluntary control of precise, directional contractions... frontalis muscles : Implications for clinical use." Thesis, Roehampton University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382549.
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Keating, Jennifer. "Relating forearm muscle electrical activity to finger forces." Digital WPI, 2014. https://digitalcommons.wpi.edu/etd-theses/580.
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The electromyogram (EMG) signal is desired to be used as a control signal for applications such as multifunction prostheses, wheelchair navigation, gait generation, grasping control, virtual keyboards, and gesture-based interfaces [25]. Several research studies have attempted to relate the electromyogram (EMG) activity of the forearm muscles to the mechanical activity of the wrist, hand and/or fingers [41], [42], [43]. A primary interest is for EMG control of powered upper-limb prostheses and rehabilitation orthotics. Existing commercial EMG-controlled devices are limited to rudimentary control capabilities of either discrete states (e.g. hand close/open), or one degree of freedom proportional control [4], [36]. Classification schemes for discriminating between hand/wrist functions and individual finger movements have demonstrated accuracy up to 95% [38], [39], [29]. These methods may provide for increased amputee function, though continuous control of movement is not generally achieved. This thesis considered proportional control via EMG-based estimation of finger forces with the goal of identifying whether multiple degrees of freedom of proportional control information are available from the surface EMG of the forearm. Electromyogram (EMG) activity from the extensor and flexor muscles of the forearm was sensed with bipolar surface electrodes and related to the force produced at the four fingertips during constant-posture, slowly force-varying contractions from 20 healthy subjects. The contractions ranged between 30% maximum voluntary contractions (MVC) extension and 30% MVC flexion. EMG amplitude sampling rate, least squares regularization, linear vs. nonlinear models and number of electrodes used in the system identification were studied. Results are supportive that multiple degrees of freedom of proportional control information are available from the surface EMG of the forearm, at least in healthy subjects. An EMG amplitude sampling frequency of 4.096 Hz was found to produce models which allowed for good EMG amplitude estimates. Least squares regularization with a pseudo-inverse tolerance of 0.055 resulted in significant improvement in modeling results, with an average error of 4.69% MVC-6.59% MVC (maximum voluntary contraction). Increasing polynomial order did not significantly improve modeling results. Results from smaller electrode arrays remained fairly good with as few as six electrodes, with the average %MVC error ranging from 5.13%-7.01% across the four fingers. This study also identified challenges in the current experimental study design and subsequent system identification when EMG-force modeling is performed with four fingers simultaneously. Methods to compensate for these issues have been proposed in this thesis.
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Sousa, Tiago dos Santos. "Efeito do encurtamento muscular dos flexores da anca na actividade muscular dos extensores da anca, durante uma tarefa de agachamento, em jovens jogadores de futebol." Bachelor's thesis, [s.n.], 2016. http://hdl.handle.net/10284/5737.
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Projeto de Graduação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Licenciado em FisioterapiaObjetivo: O objectivo deste estudo foi comparar a força muscular dos músculos flexores e extensores da anca, assim como a resposta electromiográfica dos extensores da anca, durante uma tarefa dinâmica de agachamento, em atletas juvenis de futebol masculino, com e sem encurtamento dos músculos flexores da anca. Metodologia: 18 jogadores de futebol, do sexo masculino, pertencentes ao Padroense Futebol Clube, com média de idades de 16,0 ± 1,372 anos, peso 62,877 ± 8,945 kg e altura 1,726 ± 0,085m, participaram no presente estudo. Com recurso ao Teste de Thomas, os atletas foram seleccionados para um grupo de teste (teste de Thomas positivo – presença de encurtamento) ou um grupo de controlo (teste de Thomas negativo – ausência de encurtamento). Foi avaliada a força muscular isométrica dos músculos isquiotibiais, glúteo máximo e iliopsoas com recurso a célula de carga e foi analisada a actividade electromiográfica dos músculos isquiotibiais e glúteo máximo durante o agachamento. Resultados: Não foram observadas diferenças significativas que comprovassem a existência de diferenças para a força e a activação muscular entre atletas com e sem encurtamento muscular dos flexores da anca. Conclusão: Para a amostra estudada, não foram encontradas diferenças em termos de força e activação eletromiográfica, para os músculos em estudo, entre atletas com e sem encurtamento dos flexores da anca.
Objective: The aim of this study was to compare the muscle strength of hip flexor and extensor muscles, as well as the electromyographic response of the hip extensors during a dynamic squat task in youth male football athletes, with and without shortening of hip flexors muscles. Methodology: 18 soccer players, male, of the club Padroense Futebol Clube with a mean age of 16,0 ± 1,372, weight 62,877 ± 8,945 kg and height 1,726 ± 0,085 m participated on this study. Using the Modified Thomas Test, the athletes were selected to a test group (positive Thomas Test – presence of shortening) or a control group (negative Thomas Test – absence of shortening). Isometric muscle strength was evaluated on the hamstrings, gluteus maximus and iliopsoas muscles by using a load cell and it was analyzed the electromiographic activity of the hamstrings and gluteus maximus during squat. Results: No significant differences were found which would conclusively prove the existence of differences to the muscle strength and muscle activation between athletes with and without muscle shortening of the hip flexors. Conclusion: For the study sample, no differences were found in terms of strength and eletromyographic activation of the muscles in study, between athletes with and without shortening of the hip flexors.
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Anderson, Chad. "Probabilistic Control: Implications For The Development Of Upper Limb Neuroprosthetics." Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/195648.
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Functional electrical stimulation (FES) involves artificial activation of paralyzed muscles via implanted electrodes. FES has been successfully used to improve the ability of tetraplegics to perform upper limb movements important for daily activities. The variety of movements that can be generated by FES is, however, limited to a few movements such as hand grasp and release. Ideally, a user of an FES system would have effortless command over all of the degrees of freedom associated with upper limb movement. One reason that a broader range of movements has not been implemented is because of the substantial challenge associated with identifying the patterns of muscle stimulation needed to elicit additional movements. The first part of this dissertation addresses this challenge by using a probabilistic algorithm to estimate the patterns of muscle activity associated with a wide range of upper limb movements.A neuroprosthetic involves the control of an external device via brain activity. Neuroprosthetics have been successfully used to improve the ability of tetraplegics to perform tasks important for interfacing with the world around them. The variety of mechanisms which they can control is, however, limited to a few devices such as special computer typing programs. Because motor areas of the cerebral cortex are known to represent and regulate voluntary arm movements it might be possible to sense this activity with electrodes and decipher this information in terms of a moment-by-moment representation of arm trajectory. Indeed, several methods for decoding neural activity have been described, but these approaches are encumbered by technical difficulties. The second part of this dissertation addresses this challenge by using similar probabilistic methods to extract arm trajectory information from electroencephalography (EEG) electrodes that are already chronically deployed and widely used in human subjects.Ultimately, the two approaches developed as part of this dissertation might serve as a flexible controller for interfacing brain activity with functional electrical stimulation systems to realize a brain-controlled upper-limb neuroprosthetic system capable of eliciting natural movements. Such a system would effectively bypass the injured region of the spinal cord and reanimate the arm, greatly increasing movement capability and independence in paralyzed individuals.
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Lukyanenko, Platon. "Machine Learning and Synergy Modeling for Stable, High Degree-of-Freedom Prosthesis Control with Chronically Implanted EMG." Case Western Reserve University School of Graduate Studies / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1599128848829279.
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Stensdotter, Ann-Katrin. "Motor control of the knee : kinematic and EMG studies of healthy individuals and people with patellofemoral pain." Doctoral thesis, Umeå : Dept. of Community Medicine and Rehabilitation, Physiotherapy, Umeå Univ, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-644.
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Bene, Cheryl Renee. "Visually displayed-EMG biofeedback : training muscle relaxation in hearing impaired children :a thesis." Scholarly Commons, 1988. https://scholarlycommons.pacific.edu/uop_etds/505.
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The purpose of the present study was to test the use of visually displayed EMG biofeedback as a means for training hearing impaired adolescents to reduce anterior temporalis or frontalis muscle tension . Five male and four female hearing impaired students between the ages of 13 and 15 were chosen from the California School for the Deaf, Fremont, CA to serve as participants. Each participant was randomly assigned to either an experimental or control condition. Participants in the experimental groups were given five 15 minute EMG biofeedback training sessions. An additional group of 4 adolescents with normal hearing from Marshall Junior High School, Stockton, CA served as a hearing control group. The dependent measure was a 5 minute pretest and post-test measurement of muscle tension (in microvolts).
Split-plot analyses were performed to determine if there were significant differences between a ) the .hearing impaired experimental and the hearing impaired control groups, b) the hearing impaired control and the hearing control groups, and c) the hearing impaired experimental group and the hearing control group.
Results of the analyses showed that at post-test both the hearing impaired experimental group and the hearing control group showed a significant decrease in muscle tension F(1,7)=5.85 p< .05. The interaction was nonsignificant. Comparison of the two control groups showed that at post-test the two groups were not significantly different in levels of muscle tension. The comparison between the hearing impaired experimental and the hearing control groups resulted in a significant interaction (Group X Time of Testing) F( 1,6)=9.47, p=.02, and the main effect for time of testing approached significance.
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de, Castro Germano Andresa Mara. "Biomechanical aspects of sensitivity in relationship with motor control." Doctoral thesis, Universitätsbibliothek Chemnitz, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-217339.
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The central integration of sensory information provided by various afferent receptors is required to control human movement. Although the function of individual afferent receptors is known, the complexity and interactivity of afferent information remains unclear, especially in scenarios which involve the reduction of information provided by one or more afferent receptors. Reduced plantar sensitivity is commonly associated with postural instability, which occurs in ageing, peripheral neuropathies, and other neurological disorders like Parkinson's disease. Although there has been a great advance in understanding afferent inputs during recent years, the role of afferent information in controlling movement is still unclear. Therefore, the aim of the present thesis is to investigate the effects of reduced plantar sensitivity on quasi-static and dynamic balance control, as well as muscle reflexes. The current thesis is comprised of five experiments. Two experiments were designed as preliminary investigations, while the remaining three experiments addressed the main questions of this thesis. The first experiment investigated a basic question about subjective foot sensitivity (vibration perception) measured in two different body positions: standing and sitting. Results of Experiment I showed no differences of vibration perception between both measured conditions. Therefore, comparing data from plantar sensitivity vibration tests performed during sitting and during standing (e.g. balance) is feasible. In Experiment II, the role of afferent information from plantar mechanoreceptors on quasi-static balance was investigated using two different cooling procedures: a permanently cooling thermal platform and conventional ice pads. COP total excursions, plantar temperatures, and scores of a Visual Analogue Scale (VAS) regarding subjective pain were analyzed. Experiment II demonstrated that constant and controllable cooling via the thermal platform is the superior approach with respect to subjective pain (VAS) and to reach and maintain the desired temperature throughout the trials. Furthermore, only cooling via the thermal platform induced postural instability, revealed by increased COP values. This instability was expected due to reduced plantar input, indicating no compensation by other sensory systems. Experiment III focused on the inter- and intraday- reliability of dynamic balance responses using the Posturomed device. Generally good relative and absolute reliability were found for COP excursions. This outcome was fundamental to proceed with dynamic balance measurements using the same setup. Subsequently, effects of reduced plantar cutaneous inputs via cooling on anticipatory and compensatory balance responses (unexpected perturbations) were explored in Experiment IV. COP and EMG data were used to analyze anticipatory and compensatory balance responses. No differences in COP or EMG parameters were found for the anticipatory responses after hyper-thermia, while decreased values for compensatory balance responses were observed in response to cooling. This was interpreted as a kind of overcompensatory behavior of the central nervous system (CNS) due to more cautious behavior induced after plantar cooling. Finally, the question regarding the interaction between afferent receptors arose in Experiment V, in which the effects of reduced plantar temperatures on the Achilles tendon stretch reflex and plantar flexion were examined. Short latency responses and maximal force of plantar flexion were analyzed. Cooling resulted in decreased amplitudes of short latencies, as well as in delays in time to maximal force of plantar flexion. These findings suggest that plantar inputs participate complementarily in the Achilles stretch reflex. Collectively, the current thesis contributes to understanding how plantar receptors are involved in movement control; not only do they seem to work as independent contributors, but they also appear to interact with other afferent receptors. Furthermore, an important outcome is that the reduced plantar inputs seem to induce different alterations in the organization of CNS inputs and outputs, according to different balance tasks: quasi-static responses, anticipatory responses, and compensatory responses. For the future, the use of other methods like microneurography and electroencephalography could be helpful to gain even more understanding of afferent interactions during the control of movements. Similar protocols may also be implemented in other populations, such as elderly people or patients suffering from neurological disorders, who exhibit continued decline or degeneration of sensory receptorsDie zentrale Integration von sensorischen Informationen, die aus verschiedenen afferenten Rezeptoren zur Verfügung gestellt werden, ist erforderlich, um die menschliche Bewegung zu steuern. Obwohl die Funktion der einzelnen afferenten Rezeptoren bekannt ist, bleibt die Komplexität und Interaktivität von afferenten Information unklar, insbesondere in Szenarien, in denen die Verminderung von Informationen aus einem oder mehreren afferenten Rezeptoren eintritt. Reduzierte plantare Sensibilität wird häufig im Zusammenhang mit Haltungsinstabilität verbunden. Dies tritt häufig während des Alterns ein, bei peripheren Neuropathien und anderen neurologischen Erkrankungen, wie etwa bei der Parkinson-Krankheit. Obwohl es in den vergangen Jahren große Entwicklungen was das Verständnis afferenter Inputs gab, ist die Rolle afferenter Information bei der Bewegungskontrolle immer noch unklar. Daher ist das Ziel der vorliegenden Dissertation, den Einfluss der Beeinträchtigung der plantaren Sensibilität auf das quasi-statische und dynamische Gleichgewicht, sowie auf den Reflex der Achillessehne, zu untersuchen. Die vorliegende Dissertation ist dazu aus fünf Untersuchungen aufgebaut. Zwei Untersuchungen werden als Voruntersuchungen präsentiert, während die übrigen drei Untersuchungen auf die Kernfragen dieser Doktorarbeit gerichtet sind. Die erste Untersuchung beschäftigt sich mit der grundlegenden Fragestellung bzgl. der subjektiven Fußsensibilität (Vibrationswahrnehmung), die in zwei verschiedenen Körperpositionen gemessen wurde: Im Stehen und im Sitzen. Ergebnisse aus Untersuchung I zeigten keine Unterschiede der Vibrationswahrnehmung zwischen den beiden Körperpositionen. Daher ist es möglich, Vergleiche zwischen Daten aus plantaren Vibrationswahrnehmungstests während des Sitzens und des Stehens (z.B. bei Gleichgewichtstests) durchzuführen. In Untersuchung II wurde die Rolle afferenter Informationen plantarer Mechanorezeptoren auf das quasi-statische Gleichgewicht mittels zwei unterschiedlicher Abkühlverfahren untersucht: eine permanente Abkühlung durch eine thermische Plattform und konventionelle Eis-Pads. Es wurden der COP Gesamtweg, plantar Temperaturen und eine visuelle Analogskala (VAS) in Bezug auf subjektive Schmerzen analysiert. Untersuchung II hat gezeigt, dass eine konstante und steuerbare Abkühlung über die thermische Plattform der überlegene Ansatz in Bezug auf subjektiven Schmerz (VAS) und bzgl. des Erreichens und Erhaltens einer gewünschten Temperatur innerhalb der Messungen ist. Weiterhin wurde nur durch die Abkühlung mittels thermischer Plattform eine posturale Instabilität induziert, evident durch erhöhte COP Gesamtwege. Diese Instabilität wurde aufgrund der Beeinträchtigung der plantaren Sensibilität erwartet, was auf eine fehlende Kompensation durch andere Sinnessysteme hinzuweisen scheint. In Untersuchung III lag der Fokus auf der inter- und intra-Tag-Reliabilität dynamischer Gleichgewichtsantworten mittels des Posturomed-Trainingsgerätes. Im Allgemeinen wurden eine gute relative und absolute Reliabilität der COP Gesamtwege ermittelt. Dieses Ergebnis war von grundlegender Bedeutung, um die Nutzung des gleichen Setups für die folgenden dynamischen Gleichgewichtsmessungen (Untersuchung IV) zu ermöglichen. Anschließend wurden die Effekte einer Beeinträchtigung der plantaren Sensibilität mittels Abkühlung auf antizipatorische und kompensatorische Antworten des dynamischen Gleichgewichts (anhand unerwarteter Störungen des Gleichgewichts) in Untersuchung IV erforscht. COP und EMG Daten wurden verwendet, um die antizipatorischen und kompensatorischen Antworten des Gleichgewichts zu analysieren. Nach der Abkühlung wurden bzgl. antizipatorischer Antworten keine Unterschiede in den COP und EMG Parametern gefunden. Im Hinblick auf kompensatorische Antworten zeigten sich reduzierte COP und EMG als Reaktion auf die Abkühlung. Dies wurde wie folgt interpretiert: aufgrund eines vorsichtigen Verhaltens, ausgelöst durch die verminderten sensorischen Inputs infolge der Abkühlung, kam es zu einer Art „Überkompensierungsverhalten“ des zentralen Nervensystems (ZNS). Schließlich stellte sich die Frage der Interaktion afferenter Rezeptoren in Untersuchung V, in welcher die Effekte reduzierter plantarer Temperaturen auf den Achillessehnen-Dehnungsreflex und die Plantarflexion untersucht wurden. Kurze Latenz Antworten (short latency responses) und die maximale Kraft der Plantarflexion wurden dabei analysiert. Die Abkühlung führte zu einer verminderten Amplitude der short latency responses sowie zu Verzögerungen der Zeit bis zur maximalen Kraft der Plantarflexion. Diese Ergebnisse deuten darauf hin, dass plantare Inputs in komplementärer Weise am Achillessehnen-Dehnungsreflex beteiligt sind. Zusammenfassend lässt sich aussagen, dass die vorliegende Arbeit zum Verständnis beiträgt, wie plantare Rezeptoren an der Bewegungssteuerung beteiligt sind. Es scheint, dass diese nicht nur in unabhängiger Form zur Bewegungssteuerung beitragen, sondern dabei auch mit anderen afferenten Rezeptoren interagieren. Darüber hinaus ist ein wichtiges Resultat, dass die reduzierten plantaren Inputs scheinbar verschiedene Änderungen in der Organisation von Ein- und Ausgängen im ZNS induzieren. Dies erfolgt anhand unterschiedlicher Anforderungen an das Gleichgewicht: quasi-statische Antworten, antizipatorische Antworten und kompensatorischen Antworten. Für die Zukunft könnte die Implementierung anderer Methoden, wie Mikroneurographie und Elektroenzephalographie, hilfreich sein, um noch mehr Verständnis bezüglich afferenter Interaktionen während der Kontrolle von Bewegungen erlangen zu können. Ähnliche Protokolle könnten auch in anderen Populationen durchgeführt werden, wie ältere Menschen oder Patienten mit neurologischen Erkrankungen, die einen kontinuierlichen Rückgang oder Degenerationen sensorischer Rezeptoren zeigen
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Huh, Ravina (Eunhye). "Balance control in dance positions." Thesis, Loughborough University, 2016. https://dspace.lboro.ac.uk/2134/23054.
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The purpose of this thesis is to develop and understand dance balance characteristics on various kinds of dance, related positions and shoe types which contribute to dance performance and to understand different balance controls in various groups. The first study was conducted to examine balance into ballet 2nd position between Ballet shoes and Pointe shoes. Eight dancers performed five different conditions in ballet 2nd position (Ballet Flat, Ballet Demi, Pointe Flat, Pointe Demi, and Pointe Toe) and Centre of Pressure (COP) was used to assess balance. The second study was testing balance control and response to perturbations whilst standing on double leg stance dance positions using a moving platform. Four dance positions were performed by eight subjects (Normal Flat, Turnout Flat, Normal Demi and Turnout Demi) and the platform was moved in two different directions (Forward and Backward) at two different speeds (slow and fast). Kinetics, Kinematics and EMG data was taken from this study. The third study was taken to compare balance control and response to perturbations in single leg standing dance positions between eight dancers and eight gymnasts. The subjects performed static single leg balance in Normal Flat, Turnout Flat, Normal Demi and Turnout Demi. Also, perturbed stance trials were collected in anterior, posterior, right and left directions for two dance positions (Normal Flat and Turnout Flat) at two different speeds (slow and fast) on the moving platform. The results from the studies indicate that dancers move in Medial - Lateral direction more than in Anterior - Posterior direction on Demi-pointe and Toe standing by performing plantar flexion during ballet 2nd position. Demi-pointe position may cause longer delay of EMG latencies because CNS is probably sending information already to keep correcting balance on Demi-pointe. Dancers and Gymnasts have different balance controls due to their ways of training in their performance. Dancers generally reacted faster with slow perturbation in Turnout stance than Gymnasts because this is the particular condition which Dancers are training in.
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Rosie, Juliet. "The immediate effects of EMG-triggered neuromuscular electrical stimulation on cortical excitability and grip control in people with chronic stroke." Click here to access this resource online, 2009. http://hdl.handle.net/10292/731.
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AIM The aim of this study was to identify the immediate effects on cortical excitability and grip control of a short intervention of EMG-triggered neuromuscular electrical stimulation, compared to voluntary activation of the finger flexor muscles, in people with chronic stroke. STUDY DESIGN This experimental study used a within-subject design with experimental and control interventions. PARTICIPANTS Fifteen people with chronic stroke participated in the study. INTERVENTION Participants performed a simple force tracking task with or without EMG-triggered neuromuscular electrical stimulation of the finger flexor muscles. MAIN OUTCOME MEASURES Cortical excitability was measured by single and paired-pulse transcranial magnetic stimulation. Multi-digit grip control accuracy was measured during ramp and sine wave force tracking tasks. Maximal grip strength was measured before and after each intervention to monitor muscle fatigue. RESULTS No significant increases in cortico-motor excitability were found. Intracortical inhibition significantly increased following the EMG-triggered neuromuscular electrical stimulation intervention immediately post-intervention (t = 2.466, p = .036), and at 10 minutes post-intervention (t = 2.45, p = .04). Accuracy during one component of the force tracking tasks significantly improved (F(1, 14) = 4.701, p = .048), following both EMG-triggered neuromuscular electrical stimulation and voluntary activation interventions. Maximal grip strength reduced significantly following both interventions, after the assessment of cortical excitability (F(1, 8) = 9.197, p = .16), and grip control (F(1, 14) = 9.026, p = .009). CONCLUSIONS EMG-triggered neuromuscular electrical stimulation during short duration force tracking training does not increase cortical excitability in participants with chronic stroke. Short duration force tracking training both with and without EMG-triggered neuromuscular electrical stimulation leads to improvements in training-specific aspects of grip control in people with chronic stroke.
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Bailey, Phoebe Elizabeth Psychology Faculty of Science UNSW. "The social cognitive neuroscience of empathy in older adulthood." Awarded By:University of New South Wales. Psychology, 2009. http://handle.unsw.edu.au/1959.4/44506.
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Empathy is an essential prerequisite for the development and maintenance of close interpersonal relationships. Given that older adults are particularly vulnerable to the negative consequences of loneliness and social isolation, it is surprising that few studies have assessed empathy in this group. The current programme of research addressed this gap in the literature by testing competing predictions derived from Socioemotional Selectivity Theory and the Ageing-Brain Model for age-related sparing and impairment of empathy, respectively. Study 1 compared young (N = 80) and older (N = 49) adults?? self-reported levels of cognitive and affective empathy, and engagement in social activities. It was found that although affective empathy is spared, cognitive empathy is subject to age-related decline, and this decline mediates reductions in social participation. These data therefore affirmed the importance of further investigation into the nature, causes and potential consequences of age-related differences in empathy. Since disinhibition is one mechanism contributing to difficulty taking the perspective of another, and is known to increase with age, in Study 2, behavioural measures sensitive to inhibitory failure and to cognitive empathy were administered to young (N = 36) and older (N = 33) adults. One of the measures of cognitive empathy directly manipulated inhibitory demands, involving either high or low levels of self-perspective inhibition. The results indicated that older adults were selectively impaired on the high-inhibition condition, with cognitive disinhibition mediating this association. Study 2 therefore provided important evidence relating to one potential mechanism that contributes to age-related difficulties in perspective-taking. Studies 3 and 4 provided the first behavioural assessments of age-related differences in affective empathy by using electromyography to index facial expression mimicry. Study 3 found that young (N = 35) and older (N = 35) adults?? demonstrate comparable mimicry of anger, but older adults?? initial (i.e., implicit) reactions were associated with reduced anger recognition. Thus, to test the possibility that despite explicit recognition difficulties, implicit processing of facial expressions may be preserved in older adulthood, Study 4 compared young (N = 46) and older (N = 40) adults?? mimicry responses to subliminally presented angry and happy facial expressions. As predicted, the two groups demonstrated commensurate subconscious mimicry of these expressions. Taken together, these studies indicate that separate components of empathy are differentially affected by healthy adult ageing. Implications for competing perspectives of socioemotional functioning in older adulthood are discussed.
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Axelson, Hans. "Muscle Thixotropy : Implications for Human Motor Control." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-5791.
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Chvatal, Stacie Ann. "Muscle synergies for directional control of center of mass in various postural strategies." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/43648.
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Our long-term goal is to better understand how the nervous system controls muscles to generate movement. Our overall hypothesis is that the nervous system coordinates muscles by flexibly recruiting muscle synergies, defined here as groups of muscles simultaneously activated in fixed ratios, in order to map high-level task goals into motor actions. Here we studied muscle coordination in the context of balance control - a task that requires multisensory integration and coordination of multiple muscles, yet has a clear goal of controlling the center of mass (CoM), which can be achieved by using different strategies. If muscle synergies are a common mechanism used by the nervous system for balance control, we would expect to see the same muscle synergies used in a variety of strategies. Therefore we investigated the robustness of the muscle synergies in a variety of human postural strategies, such as standing, stepping and walking, to determine whether muscle synergies are a consistent underlying mechanism used by the nervous system. We hypothesized that muscle synergies are recruited to control a task-level variable (e.g. CoM direction) that is not specific to a particular postural strategy.
We demonstrated that similar muscle synergies are used in reactive responses to standing balance perturbations, in reactive stepping responses, in walking, and in reactive postural responses during walking, suggesting a common neural mechanism not only for balance control in various contexts, but for movement in general. The differences in the timing and spatial organization of muscle activity in standing, stepping, and walking postural responses were largely explained by altering the recruitment of a common set of muscle synergies, with the addition of only a single muscle synergy specific to each behavior. We demonstrated the functionality of muscle synergies by showing that each muscle synergy was correlated with a particular force produced at the ground and component of CoM acceleration both in stepping and in non-stepping postural responses. These results suggest that muscle synergies reflect the neural organization of the motor system, representing motor modules recruited to achieve a common biomechanical function across different postural behaviors. Additionally, muscle synergies used during walking were recruited during atypical phases of the gait cycle in response to an unexpected perturbation, in order to maintain balance and continue walking, suggesting a common neural mechanism for different balance requirements during walking. The compositions of muscle synergies used during walking were similar to those used during walking perturbations as well as standing balance perturbations, suggesting that muscle synergies represent common neural mechanisms for CoM movement control under different dynamic conditions. These results are of interest to a variety of fields such as rehabilitation science, prosthetics, and robotics.
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Rubiano, Fonseca Astrid. "Smart control of a soft robotic hand prosthesis." Thesis, Paris 10, 2016. http://www.theses.fr/2016PA100189/document.
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Le sujet principal de cette thèse est le développement d’un contrôle commande intelligentpour une prothèse de main robotique avec des parties souples qui comporte: (i) uneinterface homme–machine permettant de contrôler notre prothèse, (ii) et des stratégiesde contrôle améliorant les performances de la main robotique. Notre approche tientcompte : 1. du développement d’une interaction intuitive entre l'homme et la prothèse facilitantl'utilisation de la main, d'un système d’interaction entre l’utilisateur et la mainreposant sur l'acquisition de signaux ElectroMyoGrammes superficiels (sEMG) aumoyen d'un dispositif placé sur l'avant-bras du patient. Les signaux obtenus sontensuite traités avec un algorithme basé sur l'intelligence artificielle, en vued'identifier automatiquement les mouvements désirés par le patient.2. du contrôle de la main robotique grâce à la détection du contact avec l’objet et de lathéorie du contrôle hybride.Ainsi, nous concentrons notre étude sur : (i) l’établissement d’une relation entre lemouvement du membre supérieur et les signaux sEMG, (ii) les séparateurs à vaste margepour classer les patterns obtenues à partir des signaux sEMG correspondant auxmouvements de préhension, (iii) le développement d'un système de reconnaissance depréhension à partir d'un dispositif portable MyoArmbandTM, (iv) et des stratégieshybrides de contrôle commande de force-position de notre main robotique soupleThe target of this thesis disertation is to develop a new Smart control of a soft robotic hand prosthesis for the soft robotic hand prosthesis called ProMain Hand, which is characterized by:(i) flexible interaction with grasped object, (ii) and friendly-intuitive interaction between human and robot hand. Flexible interaction results from the synergies between rigid bodies and soft bodies, and actuation mechanism. The ProMain hand has three fingers, each one is equipped with three phalanges: proximal, medial and distal. The proximal and medial are built with rigid bodies,and the distal is fabricated using a deformable material. The soft distal phalange has a new smart force sensor, which was created with the aim to detect contact and force in the fingertip, facilitating the control of the hand. The friendly intuitive human-hand interaction is developed to facilitate the hand utilization. The human-hand interaction is driven by a controller that uses the superficial electromyographic signals measured in the forearm employing a wearable device. The wearable device called MyoArmband is placed around the forearm near the elbow joint. Based on the signals transmitted by the wearable device, the beginning of the movement is automatically detected, analyzing entropy behavior of the EMG signals through artificial intelligence. Then, three selected grasping gesture are recognized with the following methodology: (i) learning patients entropy patterns from electromyographic signals captured during the execution of selected grasping gesture, (ii) performing a support vector machine classifier, using raw entropy data extracted in real time from electromyographic signals
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Torres-Oviedo, Gelsy. "Robust muscle synergies for postural control." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/22691.
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Thesis (Ph. D.)--Biomedical Engineering, Georgia Institute of Technology, 2007.Committee Chair: Ting, Lena H.; Committee Member: Chang, Young-Hui; Committee Member: Lee, Robert H.; Committee Member: Nichols, T. Richard; Committee Member: Wolf, Steve L.
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Ray, Zachary J. "Hand Orientation Feedback for Grasped Object Slip Prevention with a Prosthetic Hand." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1461181998.
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Byrd, Mark Travis. "AN EXAMINATION OF THE EFFECTS OF BILATERAL AND UNILATERAL VERY SHORT-TERM DCER TRAINING ON STRENGTH AND NEUROMUSCULAR RESPONSES WITHIN THE LOWER LIMB BILATERAL DEFICIT." UKnowledge, 2019. https://uknowledge.uky.edu/khp_etds/63.
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The very short-term resistance training (VST) model, utilizing only 2-3 training sessions, has been used to examine early phase skeletal muscle, neural, and performance adaptations. The VST model has previously been used to examine these early phase adaptations in bilateral and unilateral, isometric, isokinetic, and dynamic muscle actions in the limbs of the upper- and lower-body. The bilateral deficit (BLD) is a phenomenon in which the sum of the forces produced unilaterally is greater than the force produced bilaterally during maximal contraction of the limbs. The appearance of a bilateral deficit has been be related to various factors; including training status and mode of training (bilateral versus reciprocal muscle actions). No previous study, however, has examined the effects of VST on the BLD. The VST model has potential implications for examining acute changes in strength and neuromuscular responses of the trained muscles. These adaptations, however, may be specific to unilateral or bilateral training. Therefore, the purposes of this study were to: 1) examine one repetition maximum (1RM) strength and neuromuscular responses (EMG AMP, EMG MPF, MMG AMP, MMG MPF) during the measurement of bilateral and unilateral leg extension exercise before and after dynamic constant external resistance (DCER) VST; 2) examine the magnitude of the BLD; 3) examine the effect of bilateral versus unilateral training on the BLD; and 4) use the neuromuscular responses measured bilaterally and unilaterally to infer about the motor unit activation strategies that may underlie the BLD and changes in 1RM strength. Twenty-four (14 males, 10 females) subjects (mean ± SD age: 23.0 ± 3.2 yr; height: 174.7 ± 8.5 cm; body mass: 75.4 ± 14.1 kg) with no resistance training experience within the last three months were randomly assigned to either the bilateral (BL) training group or the unilateral (UL) training group. The subjects completed a total of seven visits, consisting of a familiarization, pre-test visit, three training visits, and one post-test visit. The pre-test visit was used to record the subject’s electromyographic (EMG) and mechanomyographic (MMG) responses from the right and left vastus lateralis (VL) during bilateral and unilateral seated maximum isometric voluntary contractions (MVIC) and 1RM. Visits four through six were the training sessions, with each subject preforming 5 sets of 6 repetitions utilizing 65% of the 1RM for resistance where the BL group trained both limbs (right and left) at the same time and the UL group trained both limbs separately. Visit seven was the post-test and the same testing procedures as the pre-test visit were followed. Statistical analyses consisted of four-way and three-way mixed model ANOVAs, with follow up three-, two- and one-way repeated measures and/or mixed model ANOVAs, Bonferroni corrected paired, and independent samples t-tests when appropriate. An alpha level of P ≤ 0.05 was considered statistically significant for all ANOVAs. The BL group demonstrated a significant increase (p = 0.006; 6.8%) in BL1RM pre- to post-test, but no change in unilateral summed (US1RM = right + left limb; p = 0.726) 1RM strength. The UL group demonstrated an 8.7% increase in BL strength collapsed across testing mode (BL1RM and US1RM) (p = 0.0001) and UL strength (p = 0.0001) collapsed across limb (UL left + UL right/2) from pre- to post-test. The BL group had a significant (p = 0.001) increase in the BI (indicating a decrease in the BLD) from pre- to post-test, but there was no significant change for the UL group. The BL group demonstrated a significant (p = 0.029) decrease in the EMG mean power frequency (MPF) measurement pre- to post-test, however the UL group showed no change. The unilateral movement, collapsed across limbs (unilateral left and unilateral right) also showed a significant (p = 0.022) decrease in the MMG MPF measurement pre- to post-test, whereas the BL movement showed no change. These findings indicated that BL and UL DCER training increased strength after 3 training sessions. The bilateral DCER training resulted in bilateral, but not unilateral strength increases and unilateral DCER training resulting in both bilateral and unilateral strength increases. However, bilateral training was the only mode of training that significantly decreased the BLD.
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Brenner, Maximilian. "Aktivní protéza ruky." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2019. http://www.nusl.cz/ntk/nusl-401959.
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BACKGROUND: Based on mainly vascular diseases and traumatic injuries, around 40,000 upper limb amputations are performed annually worldwide. The affected persons are strongly impaired in their physical abilities by such an intervention. Through myoelectric prostheses, affected persons are able to recover some of their abilities. METHODS: In order to control such prostheses, a system is to be developed by which electromyographic (EMG) measurements on the upper extremities can be carried out. The data obtained in this way should then be processed to recognize different gestures. These EMG measurements are to be performed by means of a suitable microcontroller and afterwards processed and classified by adequate software. Finally, a model or prototype of a hand is to be created, which is controlled by means of the acquired data. RESULTS: The signals from the upper extremities were picked up by four MyoWare sensors and transmitted to a computer via an Arduino Uno microcontroller. The Signals were processed in quantized time windows using Matlab. By means of a neural network, the gestures were recognized and displayed both graphically and by a prosthesis. The achieved recognition rate was up to 87% across all gestures. CONCLUSION: With an increasing number of gestures to be detected, the functionality of a neural network exceeds that of any fuzzy logic concerning classification accuracy. The recognition rates fluctuated between the individual gestures. This indicates that further fine tuning is needed to better train the classification software. However, it demonstrated that relatively cheap hardware can be used to create a control system for upper extremity prostheses.
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Semprevivo, Riccardo. "Realization and Performance Characterization of a Myoelectric Control System for Robotic Hands Based on Kernel Ridge Regression." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
Find full textAbstract:
In the field of human-robot interaction, the research is still far to find a solution to a stable control for hand prosthesis. In particular, one of the most promising methodology is represented by the use of electromyographic signals(EMG) of the muscles as a interface between the human and the artificial limb. The EMG is already used to control robotic systems that present a little number of degrees of freedom (d.o.f.), but for more complex controls able to regulate 6 or more hand's degrees of freedom several problems persist. The nonstationarity of the EMG and the nonlinear relation related to the hand configuration, became the main problem that we have to manage. The reason is that the EMG signals change over time under the influence of various factors. One of the state of the art approaches to address this problem is the use of incremental Ridge Regression with Random Fourier Features (iRRRFF) for the myocontrol algorithm, the iRRRFF is a machine learning algorithm for nonlinear mapping that is also able to update the model with new data. This enables the possibility of a continuous adaptation to the changes in the signals. In this work we implement this control in a Matlab/Simulink environment and we create a standard procedure for its use. We use an acquisition scheme that permits to acquire 8 EMG signals of the muscles around the forearm to test the performance of this type of myocontrol and, especially, we focus on the influence of carrying out different training protocols. This was tested involving two type of subject: one expert user that already used a similar EMG system in the past and a naïve user.
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Goto, Shiho. "The Effect of Ptellofemoral Pain Syndrome on the Hip and Knee Neuromuscular Control on Dynamic Postural Control Task." University of Toledo / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1254078175.
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Arenas, Joshua A. "Evaluation of a Novel Myoelectric Training Device." VCU Scholars Compass, 2015. http://scholarscompass.vcu.edu/etd/4050.
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Recent technological developments have implemented the use of proportional control in prosthetic hands, giving rise to the importance of appropriate myoelectric control. EMG models in the past have assumed a linear proportionality to simplify the EMG-force relationships. However, it has been shown that a non-linear EMG-force relationship may be a more effective model. This study focused on evaluating three different control algorithms for a novel myoelectric training device, consisting of a toy car controlled by EMG signals from the distal muscles in the arm. Sixteen healthy adult subjects (5 male and 11 female) with an average age of 23.6 years (SD = 2.7) were asked to drive the car through a slalom course. Completion times as well as number of errors (wall hits, cone hits, and reversals) were recorded to evaluate performance. The NASA TLX was administered to evaluate psychometrics such as mental demand, physical demand, frustration, and overall workload. The average total errors per trial on the final day of testing using the linear proportional algorithm was found to be statistically significantly (p < 0.05) lower than digital and non-linear proportional. The average course completion time per trial and overall workload using the non-linear proportional algorithm was found to be statistically significantly (p < 0.05) lower than digital and linear proportional. These results suggest that a non-linear algorithm would be most appropriate for myoelectric control in prosthetic hands.
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Li, Zhan. "Nouvelle modalité de contrôle en boucle fermée de l'activation musculaire et prédiction en ligne du couple musculaire sous SEF." Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20095/document.
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La stimulation électrique fonctionnelle (SEF) est une des techniques utilisées pour la rééducation ou la suppléance fonctionnelle de déficiences motrices. Un stimulateur génère des impulsions électriques qui induisent des contractions des muscles paralysés, au travers des unités motrices toujours intactes. Aujourd'hui, les systèmes fonctionnant en boucle ouverte sont majoritairement utilisés. Ils permettent aux chercheurs d'évaluer hors-ligne de la SEF. Cependant, leur réglage reste basé sur un cycle essai-erreur ce qui est loin de simplifier la mise en œuvre de systèmes en boucle fermée. Dans cette thèse, nous proposons une méthode de prédiction en temps-réel du couple en fonction de l'EMG conduisant à une nouvelle modalité de contrôle de l'activation musculaire sous SEF. L'EMG évoquée (eEMG) donne une image de l'effet de la SEF sur l'activité musculaire et est ainsi impliquée à la fois dans l'estimation du couple en temps réel et le contrôle. Le couple articulaire peut être estimé par l'eEMG en utilisant un filtre de Kalman et un modèle NARX - RNN. Le facteur d'oubli du filtre de Kalman doit être soigneuse-ment choisi de même que les réglages du schéma de calcul. C'est une limitation en particulier quand lorsque qu'il n'y a aucune connaissance a priori sur la force générée par le sujet sous SEF. La méthode proposée NARX-RNN n'a pas ce défaut et offre de meilleures performances que le filtre de Kalman. L'estimation du couple basée eEMG est donc utilisée hors-ligne et en-ligne en temps réel. Les performances comparées des algorithmes ont été effectues sur sujets sains et sujets blessés médullaires. Par ailleurs, le système temps-réel de contrôle de l'activation musculaire basé EMG a été développé sur la technologie sans fil Vivaltis. Enfin, afin de proposer un contrôle de plusieurs muscles, le concept de synergie a été utilisée pour estimer les activations musculaires cibles à partir d'un couple articulaire désiré. Les niveaux de synergie moyenne ont été utilisés pour valider l'extraction d'activation sur le sujet non inclus dans le calcul de la moyenne. L'erreur d'estimation est de 9.3% sur l'ensemble des sujets. Ces résultats vont dans le sens d'un contrôle d'une neuroprothèse basé synergie. En effet la combinaison des eux contributions de la thèse ouvre des perspectives nouvelles de modalité de contrôle de la SEFFunctional electrical stimulation (FES) is one of existing rehabilitationtechniques to restore lost motor functions for motor-impaired subjects. Thestimulator generates electrical pulses to drive artificial contractions of theparalysed muscles, through activating intact motor units. Currently open-loopFES system is the most frequently used. The data acquired from the open-loop FESwould help researchers to make off-line analysis for evaluating performance ofFES systems. However, it should go through a trial and error manner, which isfar from facilitating a implementation of real-time closed-loop FES system.In this thesis, we propose and develop a method for real-time EMG-feedback torqueprediction and muscle activation control toward new modality in FES.The evoked electromyography (eEMG) which can reflect electrical muscleactivities under FES, is involved in both offline and real-time FES-inducedtorque estimation and muscle control systems. FES-induced joint torque can beestimated/predicted with eEMG by employing both Kalman filter and NonlinearAuto-Regressive with Exogenous (NARX) type recurrent neural network (RNN). Theforgetting factor of Kalman filter should be properly selected in advance andalso with proper computational settings. It is a limitation for some casesespecially when we do not have prior knowledge of new subject regarding expectedmuscle response intensity induced by FES. The proposed NARX-RNN does not sufferfrom such computational setting problems and also shows better estimation/prediction performances than that of Kalman filter.Evoked EMG based torque estimator is exploited from off-line situation toonline real-time system. Recursive Kalman filter and NARX-RNN are implementedfor real-time torque estimation/prediction with evoked EMG. The performance wasverified both in able-bodied and spinal cord injured subjects. Furthermore, real-time EMG-feedback muscle activation control in FES system is developed togetherwith wireless Vivaltis stimulator for specifying directly muscle activationinstead of conventionally specifying stimulation pattern.Toward natural multiple muscles control with multi-channel FES, muscle synergyconcept was introduced for inverse estimation of muscle activations from desiredjoint moment. The averaged synergy ratio was applied for muscle activationestimation with leave-one-out cross validation manner, which resulted in 9.3%estimation error over all the subjects. This result supports the common musclesynergy-based neuroprosthetics control concept. By combining this inverse estimation of muscle activations together with real-time EMG-feedback muscle activation control, it would open a new modality toward muscle synergy-basedmulti-muscle activation control in FES
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Brázdil, Štěpán. "Řízení aktivní protézy horní končetiny." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2020. http://www.nusl.cz/ntk/nusl-413016.
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This thesis focuses on the field of prosthetics, especially the issue of active prosthesis control. The goal is to perform a comprehensive analysis, design and construction of a prosthetic system that, based on the analysis of sensory data (such as an EMG signal from multiple channels), can correctly classify a gesture and a subsequent moving of the limb model. The first parts of the thesis are an important description of the critical components and important parameters of the active prosthesis system, including comparison and selection of available open source solutions. Next is a proposal of interconnection and description of individual hardware and software components. It also includes documentation of the real constructed system, which consists of the InMoov robotic hand, the Raspberry Pi controller and accessories. The results are critically evaluated in the last part of this work.
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Canino, J. Miles. "The Development and Experimental Characterization of a Haptic Feedback Array to Enhance User-Perception of Locomotor Function and Motor Control of an EMG-Controlled Prosthetic Limb." Thesis, Clarkson University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10623767.
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This dissertation presents the development and experimental evaluation of a high-resolution haptic feedback array (HRHFA) for enhanced user-perception of lower-extremity limb function. The HRHFA is comprised of a grid of miniature direct-current vibratory motors contained within a conformable, additively-manufactured harness worn on the user’s lateral forearm. A multi-dimensional control architecture was developed to convey kinematic and combined kinematic-kinesthetic sensory information associated with knee function using vibrational stimulations applied along the length of the forearm. Experimental results of the HRHFA with subjects performing level-walking gait demonstrated the ability to enable statistically significant improvements in stride and cadence reproduction, and without the need for collocating the HRHFA with the ipsilateral lower limb. Building upon these results, follow-on experimental evaluations of the HRHFA were conducted for trajectory control of a myoelectric, powered-knee transfemoral prosthesis. When compared with nominal tracking performance (i.e., myoelectric control of the prosthesis with only visual feedback of knee motion), tracking performance with haptic feedback of knee motion using the HRHFA showed significant improvements in tracking error and repeatability, with concomitant reductions in learning times.
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Crommert, Martin Eriksson. "On the role of transversus abdominis in trunk motor control." Doctoral thesis, Örebro universitet, Hälsoakademin, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-15047.
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All trunk muscles are important contributors to spine stability. However, the deepest abdominal muscle, transversus abdominis (TrA), with its characteristically horizontal fibre orientation seems to serve a unique function in trunk motor control. The main mechanical role of TrA is believed to be to contribute to vertebral alignment during imposed moments on the trunk, executed mainly via either regulating the pressure level within the abdominal cavity and/or transmit forces to the spine via the thoracolumbar fascia. However, the complete function of TrA and what factors affect its activation are still not fully understood. The purpose of the present thesis was to investigate the role of TrA in trunk motor control, specifically in relation to the presence or absence of postural demand on the trunk. The timing and magnitude of TrA activation were investigated, in relation to other trunk muscles, with intramuscular fine-wire electrodes in different loading situations and body positions with varying postural demand. In a side-lying position, with no postural demand of keeping the trunk upright, the activation of TrA was delayed relative the superficial abdominal muscles compared to previous experiments performed in a standing position. The timing and magnitude of activation of TrA did not depend upon the direction of perturbation. In the standing position, different static arm positions revealed that the activation of TrA co-varied with variations in the degree of postural demand on the trunk and also the imposed moments, regardless of moment direction. Finally, a study on rapid arm flexion movements confirmed that TrA is part of the pre-programmed anticipatory response in advance of known perturbations. The activation magnitude of TrA was the same regardless if the arm movement induced flexion or extension moments on the trunk. In conclusion, the activation of TrA is associated with the upright postural demand on the trunk and with balancing imposed moments acting on the spine, regardless their direction. The findings are in support of the beliefs that TrA act as a general, direction non specific, stabilizer of the lumbar spine.
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Entakli, Jonathan. "Implication des projections spinales de l'aire motrice supplémentaire lors d'un contrôle précis de force : étude par TMS et EEG." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4121/document.
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La dextérité, notamment la pince de précision (i.e., opposition pouce-index) est une fonction très développée chez l’homme. Elle est basée sur l’habileté à contrôler précisément et indépendamment les forces et mouvements des doigts en relation avec les contraintes de la tâche. Les muscles de la main responsables du mouvement des doigts sont gouvernés par le système corticospinal (CS) latéral. La principale source de ce système CS est l’aire motrice primaire (M1), laquelle possède des projections CS directes sur les motoneurones des muscles de la main. Cependant, d’autres projections CS en provenance des aires motrices non primaires ont été trouvées, notamment en provenance de l’aire motrice supplémentaire (SMA). Chez l’homme, la fonctionnalité de cette voie dans le contrôle habile des doigts a peu été étudiée. L’objectif de cette thèse est d’étudier, chez l’homme, l’implication des projections CS de la SMA lors de contrôle manuel précis de force. Pour ce faire, nous avons utilisé la stimulation magnétique transcrânienne (TMS) et l’électroencéphalographie (EEG).A travers différentes études, nous avons pu mettre en évidence l’importante implication de la SMA dans la dextérité. Il semblerait que cette aire puisse agir en parallèle à M1 en régulant directement l’excitabilité des motoneurones de la moelle épinière. En conclusion, nos résultats suggèrent que M1 et SMAp ont une influence directe et efficace sur la production de force pendant des tâches motrices manuelles finesHuman dexterity is a highly developed function based on the ability to independently and precisely control forces and movements of the fingers related to the constraints of the task. Hand muscles for finger movements are steered by the lateral corticospinal (CS) system. The main source of this CS system is the primary motor area (M1), which has direct CS projections on motoneurons innervating hand muscles. Recently, CS projections from non-primary motor area have also been found, especially from the supplementary motor area (SMA). However, the functionality of this CS tract in human manual force control is little studied. The aim of this thesis was to study the implication of the CS projections from SMA in precision manual force control, using electroencephalography (EEG) and transcranial magnetic stimulation (TMS).Altogether, the results obtained in our different studies show the important implication of SMA in dexterity. It appears that this area can act in parallel with M1, directly influencing excitability of spinal motoneurons. We conclude that M1 and SMA both have direct and efficient influence on force production during fine manual motor tasks
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Grönlund, Christer. "Spatio-temporal processing of surface electromyographic signals : information on neuromuscular function and control." Doctoral thesis, Umeå universitet, Institutionen för strålningsvetenskaper, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-958.
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During muscle contraction, electrical signals are generated by the muscle cells. The analysis of those signals is called electromyography (EMG). The EMG signal is mainly determined by physiological factors including so called central factors (central nervous system origin) and peripheral factors (muscle tissue origin). In addition, during the acquisition of EMG signals, technical factors are introduced (measurement equipment origin). The aim of this dissertation was to develop and evaluate methods to estimate physiological properties of the muscles using multichannel surface EMG (MCsEMG) signals. In order to obtain accurate physiological estimates, a method for automatic signal quality estimation was developed. The method’s performance was evaluated using visually classified signals, and the results demonstrated high classification accuracy. A method for estimation of the muscle fibre conduction velocity (MFCV) and the muscle fibre orientation (MFO) was developed. The method was evaluated with synthetic signals and demonstrated high estimation precision at low contraction levels. In order to discriminate between the estimates of MFCV and MFO belonging to single or populations of motor units (MUs), density regions of so called spatial distributions were examined. This method was applied in a study of the trapezius muscle and demonstrated spatial separation of MFCV (as well as MFO) even at high contraction levels. In addition, a method for quantification of MU synchronisation was developed. The performance on synthetic sEMG signals showed high sensitivity on MU synchronisation and robustness to changes in MFCV. The method was applied in a study of the biceps brachii muscle and the relation to force tremor during fatigue. The results showed that MU synchronisation accounted for about 40 % of the force tremor. In conclusion, new sEMG methods were developed to study muscle function and motor control in terms of muscle architecture, muscle fibre characteristics, and processes within the central nervous system.
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Zhang, Xiang Qin. "Estimation du couple généré par un muscle sous SEF à la base de l’EMG évoquée pour le suivi de la fatigue et le contrôle du couple en boucle fermée." Thesis, Montpellier 2, 2011. http://www.theses.fr/2011MON20191/document.
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La stimulation électrique fonctionnelle (SEF) a le potentiel de fournir une amélioration active aux blessés médullaires en termes de mobilité, de stabilité et de prévention des effets secondaires.Dans le domaine des système SEF pour les membres inférieurs, le couple articulaire adéquat doit être fournie de façon appropriée pour effectuer le mouvement prévu et maintenir l'équilibre postural. Toutefois, les changements d'état du muscle tels que la fatigue musculaire est une cause majeure qui dégrade ses performances. En outre, la plupart des patients, dont la blessure médullaire est complète, n'ont pas le retour sensorielle qui permet de détecter la fatigue et les capteurs de couples in-vivo ne sont pas disponible à l'heure actuelle. Les systèmes conventionnels de commande SEF sont soit en boucle ouverte ou pas assez robustes aux changements d'état du muscle. L'objectif de cette thèse est le développement de la prédiction du couple articulaire et la commande en boucle fermée afin d'améliorer les performances de la commande SEF en termes de précision, de robustesse et de sécurité pour les patients.Afin de prédire le couple articulaire induit de la SEF, l'électromyographie (EMG) induit est utilisé pour corréler l'activité musculaire électrique et mécanique. Bien que la fatigue musculaire représente une variation dans le temps, une dépendance aux sujets et aux protocoles, la méthode proposée d'identification adaptative, basée sur le filtre de Kalman, est capable de prédire le couple articulaire variant dans le temps de manière systématique. La robustesse de la prédiction du couple articulaire a été évaluée lors d'une tâche de suivi de la fatigue en expérimentation chez des sujets blessés médulaires.Les résultats montrent une bonne performance de suivi des variations d'état des muscles en présence de fatigue et face à d'autres perturbations. Basé sur les performances de précision de la méthode prédictive proposée, une nouvelle stratégie de commande basée sur le retour EMG, «EMG-Feedback Predictive Control» (EFPC), est proposée afin de contrôler de manière adaptative les séquences de stimulation en compensant la variation dans le temps de l'état du muscle. De plus, cette stratégie de commande permet explicitement d'éviter d'appliquer une stimulation excessive aux patients, et de générer les séquences de stimulation appropriées pour obtenir la trajectoire désirée des couples articulairesFunctional electrical stimulation (FES) has the potential to provide active improvement to spinal cord injured (SCI) patients in terms of mobility, stability and side-effect prevention. In the domain of lower limb FES system, elicited muscle force must be provided appropriately to perform intended movement and the torque generation by FES should be accurate not to lose the posture balance. However, muscle state changes such as muscle fatigue is a major cause which degrades its performance. In addition, most of the complete SCI patients don't have sensory feedback to detect the fatigue and in-vivo joint torque sensor is not available yet. Conventional FES control systems are either in open-loop or not robust to muscle state changes. This thesis aims at a development of joint torque prediction and feedback control in order to enhance the FES performance in terms of accuracy, robustness, and safety to the patients.In order to predict FES-induced joint torque, evoked-Electromyography (eEMG) has been applied to correlate muscle electrical activity and mechanical activity. Although muscle fatigue represents time-variant, subject-specific and protocol-specific characteristics, the proposed Kalman filter-based adaptive identification was able to predict the time-variant torque systematically. The robustness of the torque prediction has been investigated in a fatigue tracking task in experiment with SCI subjects. The results demonstrated good tracking performance for muscle variations and against some disturbances.Based on accurate predictive performance of the proposed method, a new control strategy, EMG-Feedback Predictive Control (EFPC), was proposed to adaptively control stimulation pattern compensating to time-varying muscle state changes. In addition, this control strategy was able to explicitly avoid overstimulation to the patients, and conveniently generate appropriate stimulation pattern for desired torque trajectory
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Igual, Bañó Carles. "Co-adaptive myoelectric control for upper limb prostheses." Doctoral thesis, Universitat Politècnica de València, 2021. http://hdl.handle.net/10251/168192.
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[ES] Mucha gente en el mundo se ve afectada por la pérdida de una extremidad (las predicciones estiman que en 2050 habrá más de 3 millones de personas afectadas únicamente en los Estados Unidos de América). A pesar de la continua mejora en las técnicas de amputación y la prostética, vivir sin una extremidad sigue limitando las actividades de los afectados en su vida diaria, provocando una disminución en su calidad de vida. En este trabajo nos centramos en los casos de amputaciones de extremidades superiores, entendiendo por ello la pérdida de cualquier parte del brazo o antebrazo.
Esta tesis trata sobre el control mioeléctrico (potenciales eléctricos superficiales generados por la contracción de los músculos) de prótesis de extremidades superiores. Los estudios en este campo han crecido exponencialmente en las últimas décadas intentando reducir el hueco entre la parte investigadora más dinámica y propensa a los cambios e innovación (por ejemplo, usando técnicas como la inteligencia artificial) y la industria prostética, con una gran inercia y poco propensa a introducir cambios en sus controladores y dispositivos. El principal objetivo de esta tesis es desarrollar un nuevo controlador implementable basado en filtros adaptativos que supere los principales problemas del estado del arte.
Desde el punto de vista teórico, podríamos considerar dos contribuciones principales. Primero, proponemos un nuevo sistema para modelar la relación entre los patrones de la señales mioélectricas y los movimientos deseados; este nuevo modelo tiene en cuenta a la hora de estimar la posición actual el valor de los estados pasados generando una nueva sinergia entre máquina y ser humano. En segundo lugar, introducimos un nuevo paradigma de entrenamiento más eficiente y personalizado autónomamente, el cual puede aplicarse no sólo a nuestro nuevo controlador, sino a otros regresores disponibles en la literatura. Como consecuencia de este nuevo protocolo, la estructura humano-máquina difiere con respecto del actual estado del arte en dos características: el proceso de aprendizaje del controlador y la estrategia para la generación de las señales de entrada.
Como consecuencia directa de todo esto, el diseño de la fase experimental resulta mucho más complejo que con los controladores tradicionales. La dependencia de la posición actual de la prótesis con respecto a estados pasados fuerza a la realización de todos los experimentos de validación del nuevo controlador en tiempo real, algo costoso en recursos tanto humanos como de tiempo. Por lo tanto, una gran parte de esta tesis está dedicada al trabajo de campo necesario para validar el nuevo modelo y estrategia de entrenamiento. Como el objetivo final es proveer un nuevo controlador implementable, la última parte de la tesis está destinada a testear los métodos propuestos en casos reales, tanto en entornos simulados para validar su robustez ante rutinas diarias, como su uso en dispositivos prostéticos comerciales.
Como conclusión, este trabajo propone un nuevo paradigma de control mioélectrico para prótesis que puede ser implementado en una prótesis real. Una vez se ha demostrado la viabilidad del sistema, la tesis propone futuras líneas de investigación, mostrando algunos resultados iniciales.[CA] Molta gent en el món es veu afectada per la pèrdua d'una extremitat (les prediccions estimen que en 2050 hi haurà més de 3 milions de persones afectades únicament als Estats Units d'Amèrica). Malgrat la contínua millora en les tècniques d'amputació i la prostètica, viure sense una extremitat continua limitant les activitats dels afectats en la seua vida diària, provocant una disminució en la seua qualitat de vida. En aquest treball ens centrem en els casos d'amputacions d'extremitats superiors, entenent per això la pèrdua de qualsevol part del braç o avantbraç. Aquesta tesi tracta sobre el control mioelèctric (potencials elèctrics superficials generats per la contracció dels músculs) de pròtesis d'extremitats superiors. Els estudis en aquest camp han crescut exponencialment en les últimes dècades intentant reduir el buit entre la part investigadora més dinàmica i propensa als canvis i innovació (per exemple, usant tècniques com la intel·ligència artificial) i la indústria prostètica, amb una gran inèrcia i poc propensa a introduir canvis en els seus controladors i dispositius. Aquesta tesi contribueix a la investigació des de diversos punts de vista. El principal objectiu és desenvolupar un nou controlador basat en filtres adaptatius que supere els principals problemes de l'estat de l'art. Des del punt de vista teòric, podríem considerar dues contribucions principals. Primer, proposem un nou sistema per a modelar la relació entre els patrons de la senyals mioelèctrics i els moviments desitjats; aquest nou model té en compte a l'hora d'estimar la posició actual el valor dels estats passats generant una nova sinergia entre màquina i ésser humà. En segon lloc, introduïm un nou paradigma d'entrenament més eficient i personalitzat autònomament, el qual pot aplicar-se no sols al nostre nou controlador, sinó a uns altres regresors disponibles en la literatura. Com a conseqüència d'aquest nou protocol, l'estructura humà-màquina difereix respecte a l'actual estat de l'art en dues característiques: el procés d'aprenentatge del controlador i l'estratègia per a la generació dels senyals d'entrada. Com a conseqüència directa de tot això, el disseny de la fase experimental resulta molt més complex que amb els controladors tradicionals. La dependència de la posició actual de la pròtesi respecte a estats passats força a la realització de tots els experiments de validació del nou controlador en temps real, una cosa costosa en recursos tant humans com de temps. Per tant, una gran part d'aquesta tesi està dedicada al treball de camp necessari per a validar el nou model i estratègia d'entrenament. Com l'objectiu final és proveir un nou controlador implementable, l'última part de la tesi està destinada a testar els mètodes proposats en casos reals, tant en entorns simulats per a validar la seua robustesa davant rutines diàries, com el seu ús en dispositius prostètics comercials. Com a conclusió, aquest treball proposa un nou paradigma de control mioelèctric per a pròtesi que pot ser implementat en una pròtesi real. Una vegada s'ha demostrat la viabilitat del sistema, la tesi proposa futures línies d'investigació, mostrant alguns resultats inicials.
[EN] Many people in the world suffer from the loss of a limb (predictions estimate more than 3 million people by 2050 only in the USA). In spite of the continuous improvement in the amputation rehabilitation and prosthetic restoration, living without a limb keeps limiting the daily life activities leading to a lower quality of life. In this work, we focus in the upper limb amputation case, i.e., the removal of any part of the arm or forearm. This thesis is about upper limb prosthesis control using electromyographic signals (the superficial electric potentials generated during muscle contractions). Studies in this field have grown exponentially in the past decades trying to reduce the gap between a fast growing prosthetic research field, with the introduction of machine learning, and a slower prosthetic industry and limited manufacturing innovation. This thesis contributes to the field from different perspectives. The main goal is to provide and implementable new controller based on adaptive filtering that overcomes the most common state of the art concerns. From the theoretical point of view, there are two main contributions. First, we propose a new system to model the relationship between electromyographic signals and the desired prosthesis movements; this new model takes into account previous states for the estimation of the current position generating a new human-machine synergy. Second, we introduce a new and more efficient autonomously personalized training paradigm, which can benefit not only to our new proposed controller but also other state of the art regressors. As a consequence of this new protocol, the human-machine structure differs with respect to current state of the art in two features: the controller learning process and the input signal generation strategy. As a direct aftereffect of all of this, the experimental phase design results more complex than with traditional controllers. The current state dependency on past states forces the experimentation to be in real time, a very high demanding task in human and time resources. Therefore, a major part of this thesis is the associated fieldwork needed to validate the new model and training strategy. Since the final goal is to provide an implementable new controller, the last part of the thesis is devoted to test the proposed methods in real cases, not only analyzing the robustness and reliability of the controller in real life situations but in real prosthetic devices. As a conclusion, this work provides a new paradigm for the myoelectric prosthetic control that can be implemented in a real device. Once the thesis has proven the system's viability, future work should continue with the development of a physical device where all these ideas are deployed and used by final patients in a daily basis.
The work of Carles Igual Bañó to carry out this research and elaborate this dissertation has been supported by the Ministerio de Educación, Cultura y Deporte under the FPU Grant FPU15/02870. One visiting research fellowships (EST18/00544) was also funded by the Ministerio de Educación, Cultura y Deporte of Spain.
Igual Bañó, C. (2021). Co-adaptive myoelectric control for upper limb prostheses [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/168192
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Heald, Elizabeth Ann. "Volitional Myoelectric Signals from the Lower Extremity in Human Cervical Spinal Cord Injury: Characterization and Application in Neuroprosthetic Control." Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1575652691235174.
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Johansson, Anders. "Context dependent adaptation of biting behavior in human." Doctoral thesis, Umeå universitet, Fysiologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-91664.
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The focus of this thesis was to study an action that humans perform regularly, namely, to hold a morsel between the teeth and split it into smaller pieces. Three different issues related to this biting behavior were addressed: (1) the effect of reduced periodontal tissues on food holding and splitting behavior; (2) the behavioral consequences of performing different bite tasks with different functional requirements, i.e., to split a peanut half resting on a piece of chocolate or to split both the peanut and the chocolate; and (3) the reflex modulations resulting from such a change in the intended bite action. The main conclusions from the experimental studies were the following: First, periodontitis, an inflammatory disease that destroys the periodontal ligaments and the embedded periodontal mechanoreceptors, causes significant impairments in the masticatory ability: the manipulative bite forces when holding a morsel are elevated compared to a matched control population and the bite force development prior to food split is altered. These changes are likely due to a combination of reduced sensory information from the damaged ligaments and to changes in the bite strategy secondary to the unstable oral situation. Second, people exploit the anatomy of jaw-closing muscles to regulate the amount of bite force that dissipates following a sudden unloading of the jaw. Such control is necessary because without mechanisms that quickly halt jaw-closing movements after sudden unloading, the impact forces when the teeth collide could otherwise damage both the teeth and related soft tissues. Splitting a piece of chocolate, for instance, regularly requires >100N of bite force and the jaws collide within 5 ms of a split. On the other hand, when biting through heterogeneous food, the bite force needs to be kept high until the whole morsel is split. The required regulation is achieved by differentially engaging parts of the masseter muscles along the anteroposterior axis of the jaw to exploit differences between muscle portions in their bite force generating capacity and muscle shortening velocity. Finally, the reflex evoked by suddenly unloading the jaw—apparent only after the initial bite force dissipation—is modulated according to the bite intention. That is, when the intention is to bite through food items with multiple layers, the reflex response in the jaw opening muscles following a split is small, thus minimizing the bite force reduction. In contrast, when the intention is to rapidly decrease the bite force once a split has occurred, the reflex response is high. This pattern of reflex modulation is functionally beneficial when biting through heterogeneous food in a smooth manner. The presented studies show the significance of integrating cognitive, physiological and anatomical aspects when attempting to understand human masticatory control.
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Welch, Torrence David Jesse. "A feedback model for the evaluation of the adaptive changes to temporal muscle activation patterns following postural disturbance." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/29674.
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Thesis (Ph.D)--Biomedical Engineering, Georgia Institute of Technology, 2009.Committee Chair: Ting, Lena; Committee Member: Chang, Young-Hui; Committee Member: Nichols, T. Richard; Committee Member: Schumacher, Eric; Committee Member: Thoroughman, Kurt. Part of the SMARTech Electronic Thesis and Dissertation Collection.