In performing manual tasks, muscles are voluntarily contracted in order to produce force and orient the limb in the desired direction. Many occupational tasks are associated with frequent musculoskeletal disorders. In tasks involving skilful manipulation, very frequently the forces are focused on the upper limb and neck. Upper extremity cumulative trauma disorders are among the more common worker related injuries. These muscle disorders may be related to repetitive exertions, excessive muscle loads and extreme postures. One of the major challenges is to quantify the muscle load and researchers have tried various measures to quantify muscle load. Joint mechanical impedance can be a robust method to quantify muscle load. Joint mechanical impedance characterizes the dynamic torque-angle relationship of the joint. Joint impedance has been measured by earlier researchers, for limited tasks, by imparting force (or angle) perturbations on the joint and relating resultant angular (or force) changes. The joint impedance gives a quantitative measure related to muscle co-contraction level. Measurement of the mechanical impedance at the workplace may provide useful information relevant to the understanding of upper limb disorders. Electromyogram (EMG) is the electrical activity of the muscle. Usually, an estimate of the EMG amplitude is obtained from the raw waveform recorded from the surface of the skin. EMG amplitude estimates can be used to non-invasively estimate torque about joints. Presently, there exists no means by which mechanical impedance can be estimated non-invasively (i.e., without external perturbations). Therefore, we proposed the use of EMG to noninvasively estimate the joint mechanical impedance. Our objective in this project was to determine the extent to which surface EMG can be used to estimate mechanical impedance. Simulation studies were first performed to understand the extent to which this tool could be useful and to determine methods to be used for the experiment. The simulations were followed by evaluating and estimating mechanical impedance using data collected from one experimental subject. Simulations helped to devise processing techniques for the measured signals and also to determine the length of data to be collected. Low pass filters for derivatives (used in the development of impedance estimates) were designed. Subtracting out a polynomial was the best approach to attenuate a low frequency drift (artifact) that occurs in torque measurements. Thirty seconds of data provided impedance estimates with a relative error of 5% when EMG amplitude estimates with SNR of 15 were used. Experimental data from constant-posture, slowly force-varying background torque level showed that the elbow joint system behaved like a second order linear system between 2 Hz and 10 Hz. Co-contraction by subjects during experiments caused impedance estimates to be unexpectedly high even at low background torque. Further experiments would need to be conducted with the subjects being instructed to avoid co-contraction.

The focus of this study was to explore the effects of training with Electromyogram (EMG) feedback relaxation on test anxiety and academic achievement. Subjects were 60 students from an Introductory Psychology Class who scored highest on the Suinn Test Anxiety Behavior Scale (STABS). Subjects were divided into three groups: (1) EMG training, (2) Attention, and (3) Control. Treatment was 12 sessions over a six-week period. A pretest and posttest of the STABS was used as a measure of anxiety with the measure of academic achievement being the first and fourth tests in the Psychology class. Analysis of covariance was used to evaluate the data. No significant difference was found between the adjusted posttest means for anxiety reduction or academic achievement.

Identifying finger and wrist flexion based actions using single channel surface electromyogram have a number of rehabilitation, defence and human computer interface applications. These applications are currently infeasible because of unreliability in classification of sEMG when the level of muscle contraction is low and when there are multiple active muscles. The presence of noise and cross-talk from closely located and simultaneously active muscles is exaggerated when muscles are weakly active such as during maintained wrist and finger flexion. It has been established in literature that surface electromyogram (sEMG) and other such biosignals are fractal signals. Some researchers have determined that fractal dimension (FD) is related to strength of muscle contraction. On careful analysis of fractal properties of sEMG, this research work has established that FD is related to the muscle size and complexity and not to the strength of muscle contraction. The work has also identified a novel feature, maximum fractal length (MFL) of the signal, as a good measure of strength of contraction of the muscle. From the analysis, it is observed that while at high level of contraction, root mean square (RMS) is an indicator of strength of contraction of the muscle, this relationship is not very strong when the muscle contraction is less than 50% maximum voluntary contraction. This work has established that MFL is a more reliable measure of strength of contraction compared to RMS, especially at low levels of contraction. This research work reports the use of fractal properties of sEMG to identify the small changes in strength of muscle contraction and the location of the active muscles. It is observed that fractal dimension (FD) of the signal is related with the properties of the muscle while maximum fractal length (MFL) is related to the strength of contraction of the associated muscle. The results show that classifying MFL and FD of a single channel sEMG from the forearm it is possible to accurately identify a set of finger and wrist flexion based actions even when the muscle activity is very weak. It is proposed that such a system could be used to control a prosthetic hand or for human computer interface.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18944号 / 工博第3986号 / 新制||工||1614(附属図書館) / 31895 / 京都大学大学院工学研究科機械理工学専攻 / (主査)教授 松野 文俊, 教授 椹木 哲夫, 教授 富田 直秀 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

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京都大学 / 新制・課程博士 / 博士(人間健康科学) / 甲第23829号 / 人健博第100号 / 新制||人健||7(附属図書館) / 京都大学大学院医学研究科人間健康科学系専攻 / (主査)教授 黒木 裕士, 教授 山田 重人, 教授 森田 智視 / 学位規則第4条第1項該当 / Doctor of Human Health Sciences / Kyoto University / DFAM

Master of Science / Department of Electrical and Computer Engineering / Steven Warren / Handgrip contractions are a useful exercise for assessing muscle fatigue in the forearm musculature. Most conventional hand-forearm ergometer systems require the researcher to manually guide subject activity, collect subject data, and assess subject fatigue after it has occurred. Since post-processing tools are not standardized for this type of experiment, researchers resort to building their own tools. This process can make comparing results between research groups difficult. This thesis presents updates to a hand-forearm ergometer system that automate the control, data-acquisition, and data-analysis mechanisms. The automated system utilizes a LabVIEW virtual instrument as the system centerpiece; it provides the subject/researcher interfaces and coordinates data acquisition from both traditional and new sensors. The system also processes the hand-forearm data within the LabVIEW environment as the data are collected. This allows the researcher to better understand the onset of subject fatigue while an experiment is in progress. System upgrades relative to prior work include the addition of new parameters to the researcher display, a change in the subject display from a binary up-down display to a sliding bar for better control over subject grip state, and a software update from a simple data acquisition and display system to a real-time processing system. The toolset has proven to be a viable support resource for experimental studies performed in the Kansas State University Human Exercise Physiology Laboratory that target muscle fatigue in human forearms. Initial data acquired during these tests indicate the viability of the system to acquire consistent and physiologically meaningful data while providing a useable toolset for follow-on data analyses.

Familial Amyloidosis with Polyneuropathy was first recognized in Portugal and reported by Andrade in 1952. The disease is rare, but clustering of the patients has been reported from Portugal, Japan and northern Sweden. The gastrointestinal involvement in the Swedish form of the disease was studied in this investigation. In a study of 52 patients on their first admission 47 displayed gastrointestinal symptoms in the form of severely altered bowel habits (intractable diarrhea and/or constipation). Steatorrhea was found in 30 out of 52 patients (58%) and an impaired d-xylose absorption in 26 out of 50 patients (52%). The steatorrhea was correlated to the degree of peripheral polyneuropathy as expressed by EMG-score. No relation could be established between steatorrhea or impaired d-xylose absorption with oral lactose and glucose tolerance tests indicating an intact entero- cyte function. A follow-up study comprising 21 patients demonstrated that all patients ultimately developed gastrointestinal symptoms and that the prevalence of diarrhea became higher with the duration of the disease. In this study steatorrhea became more frequent and was significantly related to the duration. Bile acid breath test, fecal fat determination and d-xylose tests were performed on 13 patients. Six patients with results indicating an increased bile acid deconjugation in the small bowel were treated with antibiotics for one week, after which the results had returned to normal in all. Four out of five patients with impaired d-xylose absorption before treatment also returned to normal after antibiotics. Three patients with diarrhea 3-7 times daily were considerably relieved after treatment both concerning general well-being and bowel movements. The results give strong evidence that bacterial overgrowth of the small intestine is important in causing gastrointestinal dysfunction in this disease. A histopathological study of the small intestinal mucosa on 27 patients showed that 84 percent were amyloid positive. The degree of amyloid infiltration did not correlate to the symptomatic state, steatorrhea or impaired d-xylose absorption. The surface ultrastructure was normal in all of 21 investigated cases. Radiographical and endoscopi cal studies were performed on 43 patients altogether. Evidence of gastric stasis was found in 7 out of 37 patients investigated by means of gastric x-ray and in 7 out of 28 patients at gastroscopy. No characteristic radiological appearance of the disease could be shown in the small intestine, the colon or the gall bladder. Nine patients who were operated on with the construction of an enterostomy were reported. The diversion of the fecal stream when the patients had diarrhea and were incontinent meant a considerable relief. / <p>S. 1-46: sammanfattning, s. 47-128: 6 uppsatser</p> / digitalisering@umu

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.

The focus of this study was to explore the effects of training with Electromyogram (EMG) feedback relaxation on test anxiety and academic achievement. Subjects were 60 students from an Introductory Psychology Class who scored highest on the Suinn Test Anxiety Behavior Scale lSTABS). Subjects were divided into three groups: (1) EMG training, (2} Attention, and (3} Control. Treatment was 12 sessions over a six-week period. A pretest and posttest of the STABS was used as a measure of anxiety with the measure of academic achievement being the first and fourth tests in the Psychology class. Analysis of covariance was used to evaluate the data. No significant difference was found between the adjusted posttest means for anxiety reduction or academic achievement.