Use of electromyography in studying human movement
Youlian Hong, Roger Bartlett in Routledge Handbook of Biomechanics and Human Movement Science, 2008
Electromyography involves recording the action potentials that activate skeletal muscle fibres. As early as the 1600s, scientists knew that the electromyography (EMG) signal existed (Basmajian and De Luca, 1985), but they were limited by a lack of appropriate equipment to detect the signal. Thus, the science of recording EMG signals probably received its greatest impetus from the related technique of electrocardiography (ECG), which involves detecting the electrical activity of the heart. With the advent of the electrical equipment needed to detect the EMG signal in the early 1900s, physicians began using qualitative interpretation of EMG to diagnose neuropathies and various neuromuscular disorders. Quantitative EMG, however, was not commonly used until the 1950s and 1960s, when the development of electronic integrators allowed researchers to more easily quantify the amplitude of the EMG signal (de Vries, 1966, 1968). With gradual improvements in EMG equipment and signal processing techniques, EMG has evolved to the point where it is now considered to be a very useful biological signal that contains a great deal of information regarding the state of the neuromuscular system (De Luca, 1997).
The Problems
John Greene, Ian Bone in Understanding Neurology a problem-orientated approach, 2007
These neurophysiological studies address different questions. Electromyography (EMG) detects the electrical activity of muscle fibres using a needle inserted into resting and active muscle. The pattern of activity changes if there is ongoing denervation, damage to muscle membranes, or abnormally small muscle fibres. It also allows the detection of the large motor units seen in disorders where denervation is followed by reinnervation by surviving motor axons (124). Nerve conduction studies (NCS) use electrodes to record from both motor and sensory nerves. In usual practice, only myelinated axons are studied. Information is gathered on conduction velocity and the amplitude of the nerve impulse under study. The findings often allow a distinction to be made between disorders affecting the axon and those affecting the myelin sheath. They also allow motor and sensory fibre populations to be studied independently.
The neurologic approach
Stanley Berent, James W. Albers in Neurobehavioral Toxicology, 2012
‘Electromyography’ refers to nerve conduction studies and the needle electromyography examination. The EMG examination evaluates the physiological function of the peripheral nervous system. The most important application is to patients with suspected disorders of anterior horn cells, nerve roots, peripheral nerves, neuromuscular transmission, or muscle. The EMG examination is well standardized, with established sensitivity, specificity, and reproducibility. Board certification examinations provide standards of threshold levels of competence. EMG has special application for disorders potentially caused by neurotoxicants, particularly those that produce neuropathy. EMG results are used to classify the neuropathies into broad categories, narrowing the differential diagnosis. Because of their precision, EMG studies are increasingly important to clinical pharmaceutical studies, including their role in identifying potential neurotoxicity. The methodology employed in EMG evaluations is discussed in more detail in Chapter 9 of Volume II.
Toward bio-kinematic for secure use of rehabilitation exoskeleton
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2019
J. Charafeddine, D. Pradon, S. Alfayad, S. Chevallier, M. Khalil
Gait Laboratory (Raymond Poincaré Hospital, Garches, France). A bio-kinematics study was conducted in a large room; where the patients walked a straight line for 10 meters. The acquisition system includes:Video equipment to record the front and the profile of the patient.An optoelectronic system to measure the segment kinematics and the joint angles of the knee and the hip steps with respect to each foot (left and right).Ground force platforms to record dynamics (recording of ground reaction forces and the moments).An electromyographic system to record muscle activity. Electrodes were placed at the level of two biarticular muscle groups (quadriceps and hamstrings) for the knee and the hip on each leg (left and right). Everything was synchronized and connected to a computer for data acquisition. Kinematic measurements and electromyographic data were taken and recorded for three rhythms velocities (fast, normal and slow) and for 11 walking cycles at each velocity.
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
Short-term effects of postural control by standing on a tilting board in patients with Parkinson’s disease
Published in Physiotherapy Theory and Practice, 2021
Naoya Hasegawa, Keita Ishikawa, Yuki Sato, Yasuhide Nakayama, Tadayoshi Asaka
Foremost is the small sample size, which may have limited the identification between-group differences. Second, the tilted support group experienced a single long-duration trial, while the voluntary forward lean group experienced multiple, short repeated trials. This difference may play a role in the between-group differences as the interpretation hinges upon sensory re-weighting and adaptation. Third, the BBS was used for assessing clinical balance function in this study. Leddy, Crowner, and Earhart (2011) showed a ceiling effect for people with PD and there are no items to assess reactive postural control in BBS. Therefore, the other clinical tests such as the Fullerton Advanced Balance Scale or Mini Balance Evaluation System Test could be more appropriate. The learning effects of this intervention should be further investigated with a retention test. Furthermore, muscle activities should be investigated using electromyography to understand the mechanism of the effects of this intervention.
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