In many H-reflex studies, the modulation of the H-reflex is usually compared relative to the normal EMG activity within the muscle. Such comparisons enable the investigators to infer whether the change in the amplitude of the H-reflex was independent of normally occurring muscle activity. This interpretation of the H-reflex is regarded as H-reflex gain, a popular dependent variable in human H-reflex studies. However, in many studies to date, the muscle activity level has been determined from the same EMG signal from which the H-reflex is recorded. This leads to an important methodological consideration: measuring the ongoing normal EMG activity from the same signal might result in an inaccurate measurement, since this EMG signal will need to be minimally amplified to capture the synchronous volley of the H-reflex amplitude. In this study we examined this possibility and found that comparing the EMG activity level from the seated position to standing position yields different results (on average 8.03% in the measurement of the increase of muscle activity). This difference was both dependent on the task and also on the EMG instrumentation used. To solve this problem we suggest the bifurcation of the EMG signal from the recording electrodes with differential amplification of the signal. With this method, both the naturally occurring muscle activity and the H-reflex signal are collected from the same area of the muscle and a more accurate measurement of the H-reflex gain will be yielded.
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http://dx.doi.org/10.1016/j.jelekin.2010.07.014 | DOI Listing |
Gait Posture
December 2024
The Robert Jones and Agnes Hunt Orthopaedic Hospital, NHS Foundation Trust, Oswestry, SY10 7AG, United Kingdom; School of Pharmacy and Bioengineering, Keele University, Guy Hilton Research Centre, Thornburrow Drive, Stoke-on-Trent, ST4 7QB. Electronic address:
Background: Electromyography (EMG) can estimate the magnitude and timing of muscle activation during walking in those with gait disorders. Despite the potential of EMG use in assessment and clinical decision-making, there are reports of declining use of EMG within gait laboratories. Technical and educational barriers to EMG usage in clinics in Italy were recently suggested.
View Article and Find Full Text PDFGait Posture
December 2024
Department of Orthopedic Surgery, Division of Orthopedic Research, Mayo Clinic, Rochester, MN, USA. Electronic address:
Background: Back muscles simultaneously drive spinal movements and stabilize the trunk. Paraspinal muscle activity is presumed to be symmetric and gender-insensitive, and more activated with aging to protect the spine during functional tasks.
Research Question: Does over-activated and asymmetric behaviors exist in the pain-free elderly population which is affected by their physical activity levels?
Methods: Forty healthy participants (aged 64.
Biomed Eng Online
December 2024
Department of Clinical Physiology, Motion Analysis Center, University Hospital of Toulouse, Hôpital de Purpan, Toulouse, France.
Background: Stroke is the leading cause of acquired motor deficiencies in adults. Restoring prehension abilities is challenging for individuals who have not recovered active hand opening capacities after their rehabilitation. Self-triggered functional electrical stimulation applied to finger extensor muscles to restore grasping abilities in daily life is called grasp neuroprosthesis (GNP) and remains poorly accessible to the post-stroke population.
View Article and Find Full Text PDFDysphagia
December 2024
University of Canterbury Rose Centre for Stroke Recovery and Research, St George's Medical Centre, Level One, Leinster Chambers, 249 Papanui Road, Merivale, Christchurch, 8014, New Zealand.
J Neuroeng Rehabil
December 2024
Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA.
Background: This research aims to improve the control of assistive devices for individuals with hemiparesis after stroke by providing intuitive and proportional motor control. Stroke is the leading cause of disability in the United States, with 80% of stroke-related disability coming in the form of hemiparesis, presented as weakness or paresis on half of the body. Current assistive exoskeletonscontrolled via electromyography do not allow for fine force regulation.
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