Effects of functional electrical stimulation (FES) on evoked muscular output in paraplegic quadriceps muscle

Abstract

In order to assess the effects of FES on muscle output, chronic electrical stimulation of the quadriceps muscle was applied for half an hour twice a day for 2 months, in 10 thoracic level traumatic paraplegic patients. Results concerning torque (at 6 different muscle lengths) and fatigue were measured using a strain gauge transducer in isometric condition, and compared with the findings in 15 paraplegic patients who had not received electrical stimulation, and with 10 able bodied subjects with normal motor functions. With training, muscle strength was very significantly improved whilst fatigue resistance re mained at a low level. The peak torque was not found to be of the same muscle length when comparing paraplegics and control subjects; it seemed to demon strate that length-tension relationship of the muscular actuator was changing when it was electrically activated. Moreover, the force recorded in paraplegics remained markedly lower than in able bodied people.

Influence of complete spinal cord injury on skeletal muscle cross-sectional area within the first 6 months of injury

“…Patients with spinal cord injury (SCI) undergoing surface functional electrical stimulation years after injury show low force and/or work output (Pacy et al 1987;Levy et al 1990; Rabischong and Ohanna 1992;Greve et al 1993). Muscle wasting probably makes a large contribution to this compromised performance.…”

Can the efficacy of electrically stimulated pedaling using a commercially available ergometer BE improved by minimizing the muscle stress–time integral?

“…Subject-specific simulations would have accounted for the muscle-tendon properties (e.g., maximum muscle force, fiber type distribution, fiber lengths, and tendon slack lengths) of the individual subjects in the calculation of the electrical stimulation amplitudes and on and off times and could have led to improved pedaling outcomes. However, the electrical stimulation amplitude-to-force relationship varies greatly among SCI individuals 19,46,47 and depends on many stimulation variables, including electrode placement, muscle strength, fiber-type distribution, and skin impedance. Because the aforementioned stimulation variables would have been difficult to measure and control in the experimental tests and unrealistic to measure in most clinical or home settings, the generic model was used.…”

Restoration of motor function following spinal cord injury via optimal control of intraspinal microstimulation: toward a next generation closed-loop neural prosthesis

“…Implanted neurostimulation systems are associated with electrical current delivery via both intramuscular and nerve cuff electrodes (Rabischong and Ohanna, 1992; Peckham et al, 2002; Guiraud et al, 2006). As the name implies, intramuscular stimulation relies on electrodes implanted directly into the muscle (Crago et al, 1980; Hobby et al, 2001; Peckham et al, 2001, 2002; Peckham and Knutson, 2005; Kilgore et al, 2008).…”