• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 596
  • 368
  • 93
  • 34
  • 13
  • 12
  • 12
  • 12
  • 12
  • 12
  • 12
  • 6
  • 5
  • 5
  • 4
  • Tagged with
  • 1291
  • 599
  • 261
  • 163
  • 116
  • 98
  • 97
  • 95
  • 95
  • 93
  • 90
  • 86
  • 84
  • 84
  • 74
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

A real-time surface EMG topographic system for lumbar muscular function detection

Kwok, Wai-lun., 郭偉麟. January 2012 (has links)
Surface electromyography (SEMG) has been widely used in functional measurement of lumbar muscles, which can be applied for low back pain (LBP) rehabilitation assessment. Previous study has reported the application of SEMG topographic analysis for obtaining an objective and quantitative assessment of LBP. However, the previous SEMG topographic analysis was performed manually and offlined, which was time consuming and with big inter-observer variations. This will limit the use of this technique for practical assessment of LBP and rehabilitation. Therefore, the objectives of this thesis are to design and develop an automatic and online SEMG topographic analysis system, and to verify its potential uses in clinical tests. Current problems in the process of SEMG topographic analysis include noise removal and signal segment. The recording of SEMG on lumbar area is usually contaminated with a lot of noises, while electrocardiography (ECG) is a main source of influences to mislead the characteristics of SEMG. Previous study proved the use of independent components analysis (ICA) to be a useful tool to eliminate ECG from raw SEMG signals, but it was not implemented in current available SEMG system. The second problem is the automatic identification of SEMG signals in different motion phases, i.e. trunk flexion and extension during forward-bending motion. To achieve an automatic and online SEMG topographic analysis, the present study will develop the system with three unique functional components: 1) an automated feature cognition and identification for ECG artifact removal, 2) an automatic segmentation algorithm for signal processing, and 3) a quantitative analysis of SEMG topographic characteristics. Four topographic parameters, namely relative area (RA), relative width (RW), relative height (RH) and relative width-to-relative height (W/H), are employed for quantifying the characteristics of SEMG topograph. A clinical test, enlisting twenty healthy subjects and forty-one LBP patients, was conducted to verify the functionality and reliability of the developed system based on these four parameters. In addition, the dynamic variation of these four topographic parameters with respect to time was also studied by asking the subjects to perform forward-bending movements. Results showed that the developed system is highly reliable. From the results, it was also found that the time-based changing patterns of the four topographic parameters in healthy subjects can be used as a reference indicator for distinguishing between normal subjects and LBP patients. The applicability of the developed system was further verified and demonstrated by studying the effect of wearing soft lumbar corsets (SLCs) on low back neuromuscular function in elderly patients with acute LBP. In conclusion, the developed real-time SEMG topographic analysis system can be used for detecting lumbar muscle function and producing quantitative assessment results for various rehabilitation applications. / published_or_final_version / Mechanical Engineering / Master / Master of Philosophy

Application of surface electromyography topography in low back pain rehabilitation

Tse, Yuk-hang, Jessica, 謝毓衡 January 2014 (has links)
The management of low back pain (LBP) has long been a challenge as it is a highly prevalent disease worldwide due to the lack of an apparent etiology and a conclusive therapeutic treatment. Heterogeneous groups of LBP patients with diverse medical backgrounds also complicate the problem. A clinical threshold is demanded to match the patients and treatments appropriately in order to maximize the treatment success rate. Besides, the assessments of disability and pain perception due to LBP made by self-evaluated questionnaires in current clinical setting are highly susceptible to subjective feeling and the memory of patients. LBP and spasm are closely related but little is known for the underlying physiology, especially the musculature of LBP patients with spasm. These problems exacerbate the difficulty in LBP rehabilitation further. Surface electromyography (sEMG) topography is a cutting- edge technology to assess the lumbar muscle in vivo non-invasively by illustrating the distribution of global muscle activity visually. sEMG topography has the potential application as an objective assessment tool for LBP rehabilitation. In present study, sEMG topography was used to address 1) the prognostic value of sEMG topography on LBP rehabilitation, 2) the establishment and validation of a clinical classification threshold for identification of LBP patients who are responsive to exercise therapy and 3) the investigation of sEMG topography in accordance with the physiological outcomes (functional disability, pain perception and spasm). Forty-five healthy subjects and fifty patients with chronic non-specific LBP were enrolled to the study. sEMG test was conducted to every subject under the motions of lumbar flexion and extension in order to gather the myoelectric signals by a 16-channel sEMG. Various sEMG topographic parameters (sEMG parameters) were developed for quantitative analysis of sEMG topography. They were Root-Mean-Square-Difference of Relative Area (RMSD RA), Relative Width (RMSD RW) and Relative Height (RMSD RH) at flexion and extension. Results showed that sEMG parameters were of significant prognostic value for LBP patients towards exercise therapy. A clinical threshold of 0.21 was proposed and validated based on the geometric calculation of RMSD RA and RMSD RW at flexion and extension. The threshold was substantiated to increase the success rate of exercise therapy from 46% to 86% when the value measured by sEMG topography was below 0.21. sEMG parameters were found significantly associated with disability and pain perception in a positive manner. Severer disability and pain perception were represented by larger values of sEMG parameters. sEMG topography demonstrated symmetric patterns for patients with or without spasms on bilateral sides of lumbar muscles. The symmetry in sEMG topography evinced the consistency of the musculature of bilateral lumbar muscles while the lost of symmetry might indicate malfunction of lumbar muscles unilaterally. To conclude, this study corroborated versatile roles of sEMG topography in LBP rehabilitation as a prognosis, clinical threshold, and objective measurement. The findings of this study have paved the way of sEMG topography for future application in clinical setting. A study of larger scale would be recommended to complement the present findings. / published_or_final_version / Orthopaedics and Traumatology / Master / Master of Philosophy

Thinking, Feeling and Discriminating: The Role of Prejudice as a Mediator between Stereotypes and Discrimination

Ryan, John Patrick 02 August 2006 (has links)
Relationships between implicit measures of stereotyping (using subliminal semantic priming) and implicit measures of prejudice (using facial electromyography) were examined in both Black and White participants. Race of the participant showed a trend towards moderating the relationship between priming bias scores and EMG bias to face stimuli and the relationship between priming bias scores and EMG bias. There were nonsignificant relationships between priming bias scores and differences in application ratings for Black and White applicants. The issue of statistical power is discussed as a possible explanation for nonsignificance.

A study of the galvanic skin response as a measure of human energy expenditure

Horton, Francis Knapp 05 1900 (has links)
No description available.

Motor Unit Number Estimates and Quantitative Motor Unit Potentials Analysis Associated with Motor Deficits in Carpal Tunnel Syndrome

Nashed, Joseph 17 September 2008 (has links)
The purpose of this study was to determine the utility of decomposition-based quantitative electromyography (DQEMG) in detecting signs of motor unit loss and collateral sprouting in compression neuropathy. In order to accomplish this, needle- and surface-detected motor unit potential (MUP) morphological features, determined by DQEMG, were used to determine evidence of collateral sprouting. Evidence of motor unit loss was measured using motor unit number estimates (MUNEs). Six subjects with severe carpal tunnel syndrome (CTS), eight subjects with mild CTS and nine healthy individuals with no known neuropathy participated in this cross sectional study. All subjects completed two phases of data collection: 1) an examination consisting of physical and electrophysiological tests to assess the presence and/or severity of CTS and 2) quantitative electromyography techniques to record MUNEs and MUP morphological characteristics. The needle-detected MUP parameters included peak-to-peak amplitude, duration and number of phases. The presence of satellite potentials was also investigated in the needle-detected MUPs. The surface-detected MUP parameters examined included peak-to-peak amplitude, duration and negative peak area. Kruskall-Wallace tests were used to determine group differences for all outcome measures. The MUNEs were lower (p<0.017) in the severe CTS group as compared to those with mild or no CTS. This result suggests that individuals with severe CTS experience a decrease in the number of functioning motor units. Despite statistically similar surface-detected MUP morphology, there were significantly larger needle-detected MUP amplitudes (p<0.017) and satellite potentials (p<0.05) were present in the severe CTS group as compared to the mild CTS group and healthy control group. These findings suggest there is collateral reinnervation in individuals with severe CTS. The results of this study support the use of DQEMG in future studies of compression neuropathies as an effective means to document the progression of motor deficits. / Thesis (Master, Rehabilitation Science) -- Queen's University, 2008-09-16 12:08:13.587

The effect of weight and weight distribution on upper extremity muscular fatigue during static rifle aiming

SELINGER, JESSICA 08 June 2010 (has links)
Modern weapon-mounted technologies, such as novel sighting devices, detachable grenade launchers, and telescopic butt stocks, add considerable weight to weapons and alter the center of mass (COM). Currently, few objective studies have investigated the effects of these alterations on soldiers’ rifle handling. The purpose of this study was to examine the effect of weight and weight distribution on upper extremity muscular fatigue during static rifle aiming. Custom testing rigs were designed to allow the weight and COM of the in-service C7A2 assault rifle to be altered using supplementary weights and an adjustable rail system. Seven rifle configurations, each of which represented the weight and COM of a potential future design, were assessed. Soldiers performed static rifle holds with each of the rifle configurations. Upper extremity muscle activity was monitored using surface electromyography (EMG) and a subjective scale of perceived exertion. Dependent measures included muscular activity level (integrated EMG), rate of muscular fatigue (slope of the median power frequency), and subjective ratings of perceived exertion (Borg CR10 scale). The body areas exhibiting the most muscular strain throughout testing were also subjectively assessed using a body map. The results revealed that the muscle activation levels of the supporting arm were substantially greater (>30% increase) when the COM was shifted forward 7cm. This objective finding was supported by the soldiers’ subjective perceptions of muscle effort. Conversely, muscle activity levels did not make evident the effects of added weight; although this may have been largely due to the fact that muscle activity from the lower back was not captured. Rates of muscle fatigue were found to be greater in the anterior deltoid than other extremity muscles and fatigue levels were greater in the supporting arm than the trigger arm. However, using rates of fatigue it was not possible to differentiate between weight conditions and COM positions. Despite the limitations of this study, it has provided a starting point toward developing a standardized protocol for assessing muscular demands during rifle aiming. / Thesis (Master, Kinesiology & Health Studies) -- Queen's University, 2009-09-18 10:24:26.909

Neuromuscular control of human forearm movements studied with active dynamic loading.

Kwee, Him Hok January 1971 (has links)
No description available.

Normalisation of electromyograms

Burden, Adrian M. January 2002 (has links)
No description available.

Surface EMG of the rectus abdominis, comparing two strengthening exercises in crook lying :

Richoz, Christophe. January 1998 (has links)
Thesis (MAppSc in Physiotherapy) -- University of South Australia, 1998

A comparison of surface EMG temporal and spectral parameters from the vastus medialis of subjects with and without knee joint osteoarthritis during a sustained, fatiguing submaximal isometric contraction

Molloy, John Unknown Date (has links)
Knee joint osteoarthritis is recognised as a significant subset of osteoarthritis. Little work has examined muscle changes that occur with knee joint osteoarthritis. Much of this work has centred on strength deficits, while little work has examined the effect of joint pathologies, such as osteoarthritis, on the fatigue resistance of the muscles associated with an affected joint. The purpose of this study was to investigate the relative fatigue-resistance characteristics of the vastus medialis in subjects with and without knee joint osteoarthritis, as well as the ability to predict endurance times in these groups, using high spatial resolution electromyography and a sub-maximal isometric endurance test. Twenty-six subjects with unilateral knee osteoarthritis and seventeen subjects with no known knee pathology were evaluated. All subjects performed initial tests to evaluate maximum voluntary contraction (MVC), voluntary activation levels, and true maximum force (TMF). Endurance time was assessed during an isometric quadriceps contraction at 50% of the true maximum force. Surface electromyography (sEMG) data was collected from the vastus medialis muscle of the quadriceps group during the endurance test. MVC tests showed that the affected leg of the group with osteoarthritis was significantly weaker (p < 0.05) than the unaffected leg. Voluntary activation data showed that subjects with osteoarthritis presented with significant bilateral deficits (p < 0.05). TMF data showed a significantly lower (p < 0.05) true potential for force generation in the affected compared to the unaffected leg of the osteoarthritis group. Endurance time data showed no significant difference between groups. Electromyography data showed significant differences (p < 0.05) between the affected and unaffected legs in initial values of Median Frequency (MDF), Mean Power Frequency (MPF) and Conduction Velocity (CV), the percentage change in CV and the relative rate of change in the frequency band between 5 and 30Hz (FB1). Finally, significant correlations were seen between endurance time and the relative rate of change of MDF, MPF and CV calculated over the initial thirty seconds of the endurance test. There were no significant correlations from either leg of the group with knee joint osteoarthritis.It can be concluded from this study that there are differences in strength measures, and in the sEMG signal collected from the vastus medialis muscle of the affected and unaffected legs of subjects with knee osteoarthritis. It appears likely that the differences observed in the sEMG signals were related to a decrease in the representation of type-2 muscle fibres in the vastus medialis of the affected leg. Furthermore, these changes in the behaviour of the signal appear to indicate an improvement in the relative fatigue resistance of the affected leg in relation to the unaffected leg of the group with knee osteoarthritis.Moderate success was seen with the prediction of endurance time in control subjects in the current work using a short duration (30-second) endurance test. This relationship was not seen in either the affected or unaffected leg of the subjects with knee osteoarthritis. Further investigation utilising different sEMG collection and analysis techniques in this area may improve prediction of endurance time in unaffected and affected subjects.

Page generated in 0.0657 seconds