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Electromyograms
Published in A. Bakiya, K. Kamalanand, R. L. J. De Britto, Mechano-Electric Correlations in the Human Physiological System, 2021
A. Bakiya, K. Kamalanand, R. L. J. De Britto
Electromyograms are electrical signals acquired from the muscles which are used to diagnose various neuromuscular disorders. The functional phenomenon of the muscles are well described by the measured EMG signals The proper selection of electrode types and the proper localization of electrodes in the muscle regions will improve the accuracy of the overall diagnostic process. Further, the quantitative analysis of EMG signals facilitates the design and development of computer-aided diagnostic systems for the analysis of neuromuscular pathologies.
Muscle Physiology and Electromyography
Published in Verna Wright, Eric L. Radin, Mechanics of Human Joints, 2020
The relative merits of extra- and intramuscular EMG recording methods are hotly debated, and one school of thought dismisses surface electrodes as inaccurate (21). A number of authors agree, however, that in dynamic studies, surface electrodes are more comfortable for the patient and more likely to give reproducible results (23,26,28,32,33). Further credence is given to the use of surface electromyography for dynamic studies by an investigation in which both surface and intramuscular EMG were recorded simultaneously and a linear relationship was found between the two (34).
Bioelectric and Biomagnetic Signal Analysis
Published in Arvind Kumar Bansal, Javed Iqbal Khan, S. Kaisar Alam, Introduction to Computational Health Informatics, 2019
Arvind Kumar Bansal, Javed Iqbal Khan, S. Kaisar Alam
Electromyograph is recording of the electrical activities of the muscle. Muscles are controlled by brain using electric signal from motor-neurons → muscle-fibers that contract using depolarization using a mechanism involving Na+, Ca++ and K+ ions similar to depolarization and repolarization of heart-muscles. In the normal mode, an ionic equilibrium is maintained in the muscle cells around −80 to −90 millivolts. After an electric signal is transmitted from motor-neurons through axon-interfaces to muscle-fibers (see Figure 7.22), sodium channel is activated, and the NA+ ions enter the muscle cells followed by the release of Ca++ ions depolarizing the muscle-cells.
Blue-blocking filters do not alleviate signs and symptoms of digital eye strain
Published in Clinical and Experimental Optometry, 2023
Jesús Vera, Beatriz Redondo, Alba Ortega-Sanchez, Alejandro Molina-Molina, Rubén Molina, Mark Rosenfield, Raimundo Jiménez
Electromyography is a reliable technique to study muscle function through analysis of the electrical signals originated during voluntary or involuntary muscle contractions.15 Previous studies have proved that electromyography is a useful non-invasive tool for the assessment of muscle activation and fatigue.16,17 More specifically, the activity of the orbicularis oculi (OO) is sensitive to visual discomfort and asthenopia in stressful visual conditions, and it has been proposed as an objective measure of DES.18–23 This parameter has been demonstrated to be sensitive to the manipulation of viewing distance, visual stress, prolonged near work, and display type (e.g., 2D versus 3D displays) as the electromyography activity from the OO increases during visually stressful conditions.18,19,22,24 However, Gowrisankaran and colleagues found that while the OO muscle response varied with refractive error, as well as changes in glare, contrast and font size, it was insensitive to accommodative and convergence stress while reading.19
Effect of work experience and upper-limb muscle activity on grip strength of manual workers
Published in International Journal of Occupational Safety and Ergonomics, 2023
Rahul Jain, Kunj Bihari Rana, Makkhan Lal Meena
The key limitation of this study was a lack of time to investigate the effects of user experience or effect on working felt by the workers in different sectors during work. A stepwise strategy may be used to collect unique data for distinct groups for diverse settings. Also, due to the subjects’ remote locations, it was not easy to explore their biomechanical features because motion capture for a particular activity was not achievable. If the camps had been arranged in individual villages, the outcome would have been more fruitful. As a result of the current research, it has become clear that various difficulties, particularly biomechanical elements, will require additional consideration in future studies. Therefore, the study of muscles using electromyography has a lot of potential for future research.
Inner ear impairment after stapedotomy: do the cervical vestibular evoked myogenic potentials play a diagnostic role?
Published in Acta Oto-Laryngologica, 2022
Valerio Margani, Rita Talamonti, Anna Teresa Benincasa, Alessia Gorla, Edoardo Covelli, Haitham H. Elfarargy, Maurizio Barbara
The cervical VEMPS (C-VEMPs) were searched using Eclipse Lediso software (Interacoustics A/S, Assens, Denmark) in a soundproof room. A recording electrode was placed on the junction between the middle and upper one-third of the sternocleidomastoid muscle on each side. In contrast, the reference electrode was placed on the sternoclavicular joint, with the ground electrode placed on the forehead. During the recording, the patient was instructed to sit upright and turn their head sideways at 45° to generate a constant tonic pretension of the sternocleidomastoid muscle. A resistance of <5 kΩ was required for each electrode. In Ac-VEMPs, the acoustic stimuli were delivered monaurally through a headphone. While recording Bc-VEMPs, we utilized a bone conductor placed on the mastoid process (short tone bursts: 500 Hz, >95 dB HL for Ac-VEMPs, 65 dB for BC-VEMPs; rate 5,1/s), and the myogenic potential was recorded ipsilaterally using surface electrodes. The analysis time was 70 ms, and the electromyographic signal was band-pass filtered from 10 to 1000 Hz. Every set of 150 stimuli was averaged and repeated twice to verify reproducibility, and waveforms were scaled according to the average of the EMG values recorded. The test was performed in the affected ear one day before and one month after the operation. If there were no recognizable or reproducible waveforms, the C-VEMPs response was considered absent. An abnormal or normal response was defined by looking at the biphasic wave of p13 (P1) and n23 (N1) latency and amplitude peaks without considering the relative thresholds.