"This compendium-format dissertation (i.e., comprised mostly of published and in-process articles) primarily reports on system identification methods that relate the surface electromyogram (EMG)—the electrical activity of skeletal muscles—to mechanical kinetics. The methods focus on activities of the elbow and hand-wrist. The relationship between the surface EMG and joint impedance was initially studied. My work provided a complete second-order EMG-based impedance characterization of stiffness, viscosity and inertia over a complete range of nominal torques, from a single perturbation trial with slowly varied torque. A single perturbation trial provides a more convenient method for impedance evaluation. The RMS errors of the EMG-based method were 20.01% for stiffness and 7.05% for viscosity, compared with the traditional mechanical measurement. Three projects studied the relationship between EMG and force/torque, a topic that has been studied for a number of years. Optimal models use whitened EMG amplitude, combining multiple EMG channels and a polynomial equation to describe this relationship. First, we used three techniques to improve current models at the elbow joint. Three more features were extracted from the EMG (waveform length, slope sign change rate and zero crossing rate), in addition to EMG amplitude. Each EMG channel was used separately, compared to previous studies which combined multiple channels from biceps and, separately, from triceps muscles. Finally, an exponential power law model was used. Each of these improvement techniques showed better performance (P<0.05 and ~0.7 percent maximum voluntary contraction (%MVC) error reduction from a nominal error of 5.5%MVC) than the current “optimal” model. However, the combination of pairs of these techniques did not further improve results. Second, traditional prostheses only control 1 degree of freedom (DoF) at a time. My work provided evidence for the feasibility of controlling 2-DoF wrist movements simultaneously, with a minimum number of electrodes. Results suggested that as few as four conventional electrodes, optimally located about the forearm, could provide 2-DoF simultaneous, independent and proportional control with error ranging from 9.0–10.4 %MVC, which is similar to the 1-DoF approach (error from 8.8–9.8 %MVC) currently used for commercial prosthesis control. The third project was similar to the second, except that this project studied controlling a 1-DoF wrist with one hand DoF simultaneously. It also demonstrated good performance with the error ranging from 7.8-8.7 %MVC, compared with 1-DoF control. Additionally, I participated in two team projects—EMG decomposition and static wrist EMG to torque—which are described herein. "

The majority of daily living tasks necessitate the use of bimanual movements or concurrent cognitive processing, which are often more difficult for elderly adults. With the number of Americans age 65 and older expected to double in the next 25 years, in-depth research and sophisticated technologies are necessary to understand the mechanisms involved in normal neuromuscular aging. The objective of the research is to understand the effects of aging on biological signals for motor control and to develop a methodology to classify aging and stroke populations. The methodological approach investigated the influence on correlated activity (coherence) between electroencephalogram (EEG) and electromyogram (EMG) signals into senior age. In support of classifying aging and stroke populations, the methodology selected optimal features from the time, frequency, and information theory domains. Additionally, the use of cepstral analysis was modified toward this application to analyze EEG and EMG signals. The inclusion and optimization of cepstral features significantly improved classification accuracy. Additionally, classification of young and elderly adults using Gaussian Mixture Models with Minimum Classification Error improved overall accuracy values. Contributions from the dissertation include demonstration of the change in correlated activity between EMG and EEG with fine motor simple and complex dual tasks; a quantitative feature library for characterizing the neural control of movement with aging under three task conditions; and a methodology for the selection and classification of features to characterize the neural control of movement. Additionally, the dissertation provides functional insight for the association of features with tasks, aging, and clinical conditions. The results of the work are significant because classification of the neural control of movement with aging is not well established. From these contributions, future potential contributions are: a methodology for physiologists to analyze and interpret data; and a computational tool to provide early detection of neuromuscular disorders.

This project treats of using electromyograph as a control standard for prosthetic replacement of human arm. The work is mainly focused on surface signals. Reader is briefed by creation and transmission of the signal. The work takes account of the transmission of the signal for surface electrodes and the differences between the ideal and the real connection. Another point of the thesis is the design of basic system model for simulation of the robotic arm movement, which depends on the measured signal. In the practical part there is the realization of the artificial limb movement. It starts with the roboric arm construction and continues with the communication between computer and the robotic arm. First part of practical testing ends with creating of an user interface, which is capable of control all robotic arm movements. The interface is combined with a computer model in Matlab robotic toolbox. The model is able to move in sync with the real robot. The final part is devoted to practical measurement with Biopac instruments. The obtained signal is modified to be used as controller for the robotic arm. Author's aim is to adjust this movement to be most similar to real movement.

京都大学 / 0048 / 新制・課程博士 / 博士(人間・環境学) / 甲第19794号 / 人博第765号 / 新制||人||184(附属図書館) / 27||人博||765(吉田南総合図書館) / 32830 / 京都大学大学院人間・環境学研究科共生人間学専攻 / (主査)教授 神﨑 素樹, 教授 森谷 敏夫, 教授 石原 昭彦 / 学位規則第4条第1項該当 / Doctor of Human and Environmental Studies / Kyoto University / DGAM

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This study is a subset of a larger body of research that examined shoulder time to fatigue during overhead work in an attempt to reduce the prevalence and impact of work-related musculoskeletal problems in the shoulder associated with overhead work, particularly during automobile assembly. Existing evidence suggests that shoulder injuries are diverse in terms of tissues affected and symptoms presented. Furthermore, the cause of these injuries is multifactorial. The work presented here assumes that musculoskeletal injuries of the shoulder mechanism are at least related to, if not caused by, fatigue localized to the shoulder musculature. While the exact relationship between fatigue and injury has not been clearly established, there is consensus among researchers that fatigue plays and important role. Muscular fatigue, therefore, is viewed as a surrogate measure of risk, and task design to avoid fatigue is seen as a rational method to minimize this risk. An experiment to determine the effects of tool weight on shoulder fatigue and performance during overhead work with work/rest cycles was performed. Times to fatigue were derived based on dependent measures including total task duration, controlled maximum muscle contractions, subjective ratings based on Borg's CR-10 RPE scale, electromyogram behavior (MdPF), and hand force performance measures. Experimental findings indicated that duty cycle (percentage of total task cycle time spent working) significantly affected task duration (p<0.0001), changes in maximum voluntary contraction values for the infraspinatus (p<0.05), and the minimum time for any shoulder muscle to fatigue as determined by changes in the EMG power spectrum (p<0.05). Time to fatigue for the mid deltoid as determined by changes in the median frequency of the EMG power spectrum was shown to change significantly (p<0.05) with change in tool weight. Large intersubject variation was observed for the dependent measures, which showed subjects experiencing different levels of fatigue while performing the same task. Limitations of the study and recommendations for future direction are also discussed. / Master of Science

Book Summary: This book comprehensively covers the assessment and treatment of balance system impairments. Designed to be used in graduate programs in audiology, and by practicing audiologists, it is also appropriate for those in the fields of physical therapy, otolaryngology, and neurology. Assessment chapters address ocular motility testing, positional/positioning testing, caloric testing, rotational testing, computerized dynamic posturography, and vestibular evoked potentials. Treatment chapters cover non-medical, medical, and surgical treatment of dizziness and vertigo, vestibular rehabilitation and assessment of and intervention for falls risk. Additionally, the book provides background information on the vestibular and ocular motor systems, sample cases, and a final chapter, "Putting It All Together."

[Truncated abstract] The function of the diaphragm as a volume pump has not been adequately evaluated because there are no accurate methods to measure the volume displaced by diaphragm motion (ΔVdi). As a consequence, the work done, power output and efficiency of the diaphragm have not been measured. Efficiency of the diaphragm could be measured by relating the power output of the diaphragm to its neural activation. The aims of this thesis were to (a) develop a new biplanar radiographic method to measure ΔVdi and use this to evaluate the effect of costophrenic fibrosis and emphysema on ΔVdi, (b) develop a new fluoroscopic method to enable breath-by-breath measurements of ΔVdi, (c) evaluate a method for quantifying neural activation of the diaphragm, and (d) combine measurements of transdiaphragmatic pressure, ΔVdi, inspiratory duration and neural activation of the diaphragm to quantify the neuromechanical efficiency of the diaphragm

Cette thèse a pour but de mettre au point un nouvel outil de rééducation neuromusculaire. Elle a pour fonction, l'amélioration de la qualité et de la durée des séances de renforcement musculaire et de réentraînement de la motricité de sujets atteints de déconditionnement musculaire. Un électromyostimulateur "intelligent" utilisant en même temps des techniques d'électromyostimulation (EMS) couplées aux analyses de l'électromyogramme (EMG) est développé et permet d'asservir en temps réel les paramètres de stimulation d'un muscle en fonction de son état de fatigue physiologique. Le contrôle ainsi effectué sur les paramètres de stimulation en fonction de la réponse musculaire électrique (onde M) offre la possibilité de stimuler un muscle en prenant en compte une information sur la réaction du muscle à l'électrostimulation / This project aims to develop a new tool for neuromuscular reeducation. Its function is to improve the quality and the duration of muscular strengthening training sessions and training of motor function for patients suffering from muscle deconditioning. A "smart" electromyostimulator using, at the same time, techniques of electrostimulation (EMS) and analysis of electromyography (EMG) allows the control in real time electrical stimulation parameters considering the physiological fatigue of the stimulated muscle. This control, performed on stimulation parameters depending on electrical response of muscles (M wave), allows the muscle stimulation taking into account the muscular reaction to the electrical stimulation

Humans perform complex sensorimotor tasks, such as walking on uneven terrain, in a seemingly effortless manner. However, even simple voluntary tasks, like lifting the arm to shake hands, require intricate adjustments to maintain balance. With experience, humans learn to produce the appropriate patterns of muscle activity necessary to maintain balance during everyday activities, as well as highly specialized motor tasks. Here, I investigated the neural feedback mechanisms controlling the formation of the muscle activity used during balance tasks. I hypothesized that humans use feedback from on-going balance perturbations to establish their muscular responses. Specifically, I investigated center-of-mass (CoM) kinematics as a control signal for the formation of these muscle activation patterns. Using an inverted pendulum model under delayed feedback control, I both reconstructed the temporal EMG patterns measured during experimental perturbations and predicted the optimal EMG patterns for responding to the same perturbations. By modulating four feedback parameters, this feedback law accounted for 91% of the variability in all experimentally-recorded EMG patterns - regardless of the mechanical action of the muscle or the response strategy chosen by the subject. To investigate the changes in postural control during motor learning, I used this feedback model to characterize responses while naïve subjects adapted to repetitive unidirectional and reversing perturbations. By adjusting feedback gains related to CoM velocity and displacement, subjects adapted their muscle activity to improve control over the CoM for both perturbation types. Though subjects were unable to use anticipatory strategies to reduce muscle onset latency or to mute inappropriate responses to reversing perturbations, more subtle feedforward adjustments to feedback-mediated postural responses were evident. With experience, subjects adapted their postural responses toward the optimal solution. The results of this work, when combined with on-going studies of muscle synergies, will provide a powerful tool for investigating the consequences that result from the changes in spatiotemporal muscle activity associated with aging, neurological dysfunction, musculoskeletal injury, and specialized training programs. This quantitative knowledge is critical to the development of diagnostic tools for balance and movement disorders, as well as for the design of effective interventional therapies, bipedal robots, and neural prostheses.