2011 5th International IEEE/EMBS Conference on Neural Engineering, 2011
... Content may change prior to final publication. JAKOB L. DIDERIKSEN ET AL.: NONINVASIVE FRAMEW... more ... Content may change prior to final publication. JAKOB L. DIDERIKSEN ET AL.: NONINVASIVE FRAMEWORK FOR MULTICOMPONENT AM-FM DEMODULATION OF CORTICAL TREMOR 5 a u) A EMG (a B C D 0 0.5 1 Time (s) Fig. ...
The study developed a novel multi-scale model for simulating the surface electromyogram (EMG) of ... more The study developed a novel multi-scale model for simulating the surface electromyogram (EMG) of an antagonistic pair of muscles during pathological tremor. By combining and expanding mathematical descriptions from motor units to limb kinematics, the model constitutes the first attempt to simulate the surface EMG and the individual motor unit activity under the influence of descending voluntary command, oscillatory noise in the descending signal, and afferent feedback when controlling a freely moving limb to achieve a predefined angular trajectory. The oscillatory noise was adjusted to simulate various types of pathological tremor. The simulations replicated previously reported experimental results for the power spectral density of the surface EMG, the angular velocity of the limb, and single motor unit activity. The model provides a powerful tool for extracting information about how the surface EMG can be used to describe tremor in various conditions, including different tremor frequencies and intensities, that cannot be achieved solely with experimental approaches.
Journal of applied physiology (Bethesda, Md. : 1985), 2015
Neuromuscular electrical stimulation (NMES) is commonly used in rehabilitation, but electrically ... more Neuromuscular electrical stimulation (NMES) is commonly used in rehabilitation, but electrically evoked muscle activation is in several ways different from voluntary muscle contractions. These differences lead to challenges in the use of NMES for restoring muscle function. We investigated the use of low-current, high-frequency nerve stimulation to activate the muscle via the spinal motoneuron (MN) pool to achieve more natural activation patterns. Using a novel stimulation protocol, the H-reflex responses to individual stimuli in a train of stimulation pulses at 100 Hz were reliably estimated with surface EMG during low-level contractions. Furthermore, single motor unit recruitment by afferent stimulation was analyzed with intramuscular EMG. The results showed that substantially elevated H-reflex responses were obtained during 100-Hz stimulation with respect to a lower stimulation frequency. Furthermore, motor unit recruitment using 100-Hz stimulation was not fully synchronized, as i...
2011 5th International IEEE/EMBS Conference on Neural Engineering, 2011
... Content may change prior to final publication. JAKOB L. DIDERIKSEN ET AL.: NONINVASIVE FRAMEW... more ... Content may change prior to final publication. JAKOB L. DIDERIKSEN ET AL.: NONINVASIVE FRAMEWORK FOR MULTICOMPONENT AM-FM DEMODULATION OF CORTICAL TREMOR 5 a u) A EMG (a B C D 0 0.5 1 Time (s) Fig. ...
The study developed a novel multi-scale model for simulating the surface electromyogram (EMG) of ... more The study developed a novel multi-scale model for simulating the surface electromyogram (EMG) of an antagonistic pair of muscles during pathological tremor. By combining and expanding mathematical descriptions from motor units to limb kinematics, the model constitutes the first attempt to simulate the surface EMG and the individual motor unit activity under the influence of descending voluntary command, oscillatory noise in the descending signal, and afferent feedback when controlling a freely moving limb to achieve a predefined angular trajectory. The oscillatory noise was adjusted to simulate various types of pathological tremor. The simulations replicated previously reported experimental results for the power spectral density of the surface EMG, the angular velocity of the limb, and single motor unit activity. The model provides a powerful tool for extracting information about how the surface EMG can be used to describe tremor in various conditions, including different tremor frequencies and intensities, that cannot be achieved solely with experimental approaches.
Journal of applied physiology (Bethesda, Md. : 1985), 2015
Neuromuscular electrical stimulation (NMES) is commonly used in rehabilitation, but electrically ... more Neuromuscular electrical stimulation (NMES) is commonly used in rehabilitation, but electrically evoked muscle activation is in several ways different from voluntary muscle contractions. These differences lead to challenges in the use of NMES for restoring muscle function. We investigated the use of low-current, high-frequency nerve stimulation to activate the muscle via the spinal motoneuron (MN) pool to achieve more natural activation patterns. Using a novel stimulation protocol, the H-reflex responses to individual stimuli in a train of stimulation pulses at 100 Hz were reliably estimated with surface EMG during low-level contractions. Furthermore, single motor unit recruitment by afferent stimulation was analyzed with intramuscular EMG. The results showed that substantially elevated H-reflex responses were obtained during 100-Hz stimulation with respect to a lower stimulation frequency. Furthermore, motor unit recruitment using 100-Hz stimulation was not fully synchronized, as i...
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