Publications by authors named "Jose Luis Vargas Luna"

Background: Spinal cord injuries (SCIs) are a global concern, annually affecting hundreds of thousands of individuals. Among these cases, incomplete SCIs, allowing some muscle activity below the injury, pose unique challenges. This case study focuses on a 55-year-old male with a moderate incomplete SCI (AIS-D).

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Increased use of epidural Spinal Cord Stimulation (eSCS) for the rehabilitation of spinal cord injury (SCI) has highlighted the need for a greater understanding of the properties of reflex circuits in the isolated spinal cord, particularly in response to repetitive stimulation. Here, we investigate the frequency-dependence of modulation of short- and long-latency EMG responses of lower limb muscles in patients with SCI at rest. Single stimuli could evoke short-latency responses as well as long-latency (likely polysynaptic) responses.

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The availability of engineered biological tissues holds great potential for both clinical applications and basic research in a life science laboratory. A prototype standalone perfusion/compression bioreactor system was proposed to address the osteogenic commitment of stem cells seeded onboard of 3D chitosan-graphene (CHT/G) templates. Testing involved the coordinated administration of a 1 mL/min medium flow rate together with dynamic compression (1% strain at 1 Hz; applied twice daily for 30 min) for one week.

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There is multiple evidence in the literature that a sub-threshold pre-pulse, delivered immediately prior to an electrical stimulation pulse, can alter the activation threshold of nerve fibers and motor unit recruitment characteristics. So far, previously published works combined monophasic stimuli with sub-threshold depolarizing pre-pulses (DPPs) with inconsistent findings-in some studies, the DPPs decreased the activation threshold, while in others it was increased. This work aimed to evaluate the effect of DPPs during biphasic transcutaneous electrical stimulation and to study the possible mechanism underlying those differences.

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Neuromuscular electrical stimulation (NMES) is a widely used technique for clinical diagnostic, treatment, and research. Normally, it applies charge-balanced biphasic pulses, which several publications have reported to be less efficient than monophasic pulses. A good alternative is the use of interphase intervals (IPI) on biphasic pulses that allows to achieve similar responses than those evoked by monophasic stimulation.

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Neuromuscular electrical stimulation (NMES) is an established method for functional restoration of muscle function, rehabilitation, and diagnostics. In this work, NMES was applied with surface electrodes placed on the anterior thigh to identify the main differences between current-controlled (CC) and voltage-controlled (VC) modes. Measurements of the evoked knee extension force and the myoelectric signal of quadriceps and hamstrings were taken during stimulation with different amplitudes, pulse widths, and stimulation techniques.

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Article Synopsis
  • Transcutaneous electrical stimulation uses electrodes on the skin to deliver electrical impulses that can activate nerve or muscle cells, and the effectiveness depends on the electrode-skin impedance.
  • A new dynamic impedance model is introduced that accommodates a wide range of stimulation intensities, taking into account electroporation and other charge-dependent effects.
  • The model's accuracy is supported by high coefficients of determination in simulations, making it adaptable for various electrical stimulation applications and electrode configurations.
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