- Award ID(s):
- 1847319
- PAR ID:
- 10220195
- Date Published:
- Journal Name:
- IEEE Journal of Biomedical and Health Informatics
- ISSN:
- 2168-2194
- Page Range / eLocation ID:
- 1 to 1
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Neuromuscular electrical stimulation (NMES) targeting the muscle belly is commonly used to restore muscle strength in individuals with neurological disorders. However, early onset of muscle fatigue is a major limiting factor. Transcutaneous nerve stimulation (TNS) can delay muscle fatigue compared with traditional NMES techniques. However, the recruitment of Ia afferent fibers has not be specifically targeted to maximize muscle activation through the reflex pathway, which can lead to more orderly recruitment of motor units, further delaying fatigue. This preliminary study assessed the distribution of M-wave and H-reflex of intrinsic and extrinsic finger muscles. TNS was delivered using an electrode array placed along the medial side of the upper arm. Selective electrode pairs targeted the median and ulnar nerves innervating the finger flexors. High-density electromyography (HD EMG) was utilized to quantify the spatial distribution of the elicited activation of finger intrinsic and extrinsic muscles along the hand and forearm. The spatial patterns were characterized through isolation of the M-wave and H-reflex across various stimulation levels and EMG channels. Our preliminary results showed that, by altering the stimulation amplitude, distinct M-wave and H-reflex responses were evoked across EMG channels. In addition, distinct stimulation locations appeared to result in varied levels of reflex recruitment. Our findings indicate that it is possible to adjust stimulation parameters to maximize reflex activation, which can potentially facilitate physiological recruitment order of motoneurons.more » « less
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Abstract Introduction Optimal frequency modulation during functional electrical stimulation (FES) may minimize or delay the onset of FES‐induced muscle fatigue.
Methods An offline dynamic optimization method, constrained to a modified Hill‐Huxley model, was used to determine the minimum number of pulses that would maintain a constant desired isometric contraction force.
Results Six able‐bodied participants were recruited for the experiments, and their quadriceps muscles were stimulated while they sat on a leg extension machine. The force–time (F–T) integrals and peak forces after the pulse train was delivered were found to be statistically significantly greater than the force–time integrals and peak forces obtained after a constant frequency train was delivered.
Discussion Experimental results indicated that the optimized pulse trains induced lower levels of muscle fatigue compared with constant frequency pulse trains. This could have a potential advantage over current FES methods that often choose a constant frequency stimulation train.
Muscle Nerve 57 : 634–641, 2018 -
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