Benefits Of Functional Electrical Stimulation Research Articles

Effects of Functional Electrical Stimulation Cycling of Different Duration on Viscoelastic and Electromyographic Properties of the Knee in Patients with Spinal Cord Injury.

The benefits of functional electrical stimulation during cycling (FES-cycling) have been ascertained following spinal cord injury. The instrumented pendulum test was applied to chronic paraplegic patients to investigate the effects of FES-cycling of different duration (20-min vs. 40-min) on biomechanical and electromyographic characterization of knee mobility. Seven adults with post-traumatic paraplegia attended two FES-cycling sessions, a 20-min and a 40-min one, in a random order. Knee angular excursion, stiffness and viscosity were measured using the pendulum test before and after each session. Surface electromyographic activity was recorded from the rectus femoris (RF) and biceps femoris (BF) muscles. FES-cycling led to reduced excursion (p < 0.001) and increased stiffness (p = 0.005) of the knee, which was more evident after the 20-min than 40-min session. Noteworthy, biomechanical changes were associated with an increase of muscle activity and changes in latency of muscle activity only for 20-min, with anticipated response times for RF (p < 0.001) and delayed responses for BF (p = 0.033). These results indicate that significant functional changes in knee mobility can be achieved by FES-cycling for 20 min, as evaluated by the pendulum test in patients with chronic paraplegia. The observed muscle behaviour suggests modulatory effects of exercise on spinal network aimed to partially restore automatic neuronal processes.

Supporting front crawl swimming in paraplegics using electrical stimulation: a feasibility study

BackgroundParticipation in physical and therapeutic activities is usually severely restricted after a spinal cord injury (SCI). Reasons for this are the associated loss of voluntary motor function, inefficient temperature regulation of the affected extremities, and early muscle fatigue. Hydrotherapy or swim training offer an inherent weight relief, reduce spasticity and improve coordination, muscle strength and fitness.MethodsWe present a new hybrid exercise modality that combines functional electrical stimulation (FES) of the knee extensors and transcutaneous spinal cord stimulation (tSCS) with paraplegic front crawl swimming. tSCS is used to stimulate the afferent fibers of the L2–S2 posterior roots for spasticity reduction. By activating the tSCS, the trunk musculature is recruited at a motor level. This shall improve trunk stability and straighten the upper body. Within this feasibility study, two complete SCI subjects (both ASIA scale A, lesion level Th5/6), who have been proficient front crawl swimmers, conducted a 10-week swim training with stimulation support. In an additional assessment swim session nine months after the training, the knee extension, hip extension, and trunk roll angles where measured using waterproof inertial measurement units (IMUs) and compared for different swimming conditions (no stimulation, tSCS, FES, FES plus tSCS).ResultsFor both subjects, a training effect over the 10-week swim training was observed in terms of measured lap times (16 m pool) for all swimming conditions. Swimming supported by FES reduced lap times by 15.4% and 8.7% on average for Subject A and Subject B, respectively. Adding tSCS support yielded even greater mean decreases of 19.3% and 20.9% for Subjects A and B, respectively. Additionally, both subjects individually reported that swimming with tSCS for 30–45 minutes eliminated spasticity in the lower extremities for up to 4 hours beyond the duration of the session. Comparing the median as well as the interquartile range of all different settings, the IMU-based motion analysis revealed that FES as well as FES+tSCS improve knee extension in both subjects, while hip extension was only increased in one subject. Trunk roll angles were similar for all swimming conditions. tSCS had no influence on the knee and hip joint angles. Both subjects reported that stimulation-assisted swimming is comfortable, enjoyable, and they would like to use such a device for recreational training and rehabilitation in the future.ConclusionsStimulation-assisted swimming seems to be a promising new form of hybrid exercise for SCI people. It is safe to use with reusable silicone electrodes and can be performed independently by experienced paraplegic swimmers except for transfer to water. The study results indicate that swimming speed can be increased by the proposed methods and spasticity can be reduced by prolonged swim sessions with tSCS and FES. The combination of stimulation with hydrotherapy might be a promising therapy for neurologic rehabilitation in incomplete SCI, stroke or multiples sclerosis patients. Therefore, further studies shall incorporate other neurologic disorders and investigate the potential benefits of FES and tSCS therapy in the water for gait and balance.

A Control Scheme That Uses Dynamic Postural Synergies to Coordinate a Hybrid Walking Neuroprosthesis: Theory and Experiments.

A hybrid walking neuroprosthesis that combines functional electrical stimulation (FES) with a powered lower limb exoskeleton can be used to restore walking in persons with paraplegia. It provides therapeutic benefits of FES and torque reliability of the powered exoskeleton. Moreover, by harnessing metabolic power of muscles via FES, the hybrid combination has a potential to lower power consumption and reduce actuator size in the powered exoskeleton. Its control design, however, must overcome the challenges of actuator redundancy due to the combined use of FES and electric motor. Further, dynamic disturbances such as electromechanical delay (EMD) and muscle fatigue must be considered during the control design process. This ensures stability and control performance despite disparate dynamics of FES and electric motor. In this paper, a general framework to coordinate FES of multiple gait-governing muscles with electric motors is presented. A muscle synergy-inspired control framework is used to derive the controller and is motivated mainly to address the actuator redundancy issue. Dynamic postural synergies between FES of the muscles and the electric motors were artificially generated through optimizations and result in key dynamic postures when activated. These synergies were used in the feedforward path of the control system. A dynamic surface control technique, modified with a delay compensation term, is used as the feedback controller to address model uncertainty, the cascaded muscle activation dynamics, and EMD. To address muscle fatigue, the stimulation levels in the feedforward path were gradually increased based on a model-based fatigue estimate. A Lyapunov-based stability approach was used to derive the controller and guarantee its stability. The synergy-based controller was demonstrated experimentally on an able-bodied subject and person with an incomplete spinal cord injury.

A Review on Functional Electrical Stimulation for a Dropped Foot.

The purpose of this collective review is to study the techniques, usage, methods, and clinical results of functional electrical stimulation applied to the peroneal nerve in the treatment of dropped foot. When stimulation is applied through surface electrodes, clinical reports have documented the therapeutic and orthotic benefits of functional electrical stimulation. Clinical trials are now being undertaken in which implantable electrodes are being used to stimulate the peroneal nerve in patients with dropped foot.

A report of anticipated benefits of functional electrical stimulation after spinal cord injury

BackgroundFunctional electrical stimulation (FES) has been regularly used to offset several negative body composition and metabolic adaptations following spinal cord injury (SCI). However, the outcomes of many FES trials appear to be controversial and incoherent.ObjectiveTo document the potential consequences of several factors (e.g. pain, spasms, stress and lack of dietary control) that may have attenuated the effects on body composition and metabolic profile despite participation in 21 weeks of FES training.ParticipantA 29-year-old man with T6 complete SCI participated in 21 weeks of FES, 4 days per week.MethodsPrior to and following training, the participant performed arm-crank-graded exercise testing to measure peak VO2. Tests conducted included anthropometrics and dual energy X-ray absorptiometry body composition assessments, resting energy expenditure, plasma lipid profiles and intravenous glucose tolerance tests.ResultsThe participant frequently reported increasing pain, stress and poor eating habits. VO2 peak decreased by 2.4 ml/kg/minute, body mass increased by 8.5 kg, and body mass index increased from 25 to 28 kg/m2. Waist and abdominal circumferences increased by 2–4 cm, while %fat mass increased by 5.5%. Absolute increases in fat mass and fat-free mass of 8.4 and 1 kg, respectively, were reported. Fasting and peak plasma glucose increased by 12 and 14.5%, while lipid panel profiles were negatively impacted.ConclusionFailure to control for the listed negative emerging factors may obscure the expected body composition and metabolic profile adaptations anticipated from FES training.

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

The cardiorespiratory and muscular strength benefits of functional electrical stimulation (FES) pedaling for spinal cord injury (SCI) subjects are limited because the endurance of electrically stimulated muscle is low. We tested new electrical stimulation timing patterns (Stim3, designed using a forward dynamic simulation to minimize the muscle stress-time integral) to determine whether SCI subjects could increase work and metabolic responses when pedaling a commercial FES ergometer. Work, rate of oxygen uptake (VO(2)), and blood lactate data were taken from 11 subjects (injury level T4-T12) on repeated trials. Subjects performed 11% more work pedaling with Stim3 than with existing stimulation patterns (StimErg) (P = 0.043). Average (VO(2)) and blood lactate concentrations were not significantly different between Stim3 (442 ml/min, 5.9 mmol/L) and StimErg (417 ml/min, 5.9 mmol/L). The increased mechanical work performed with Stim3 supports the use of patterns that minimize the muscle stress-time integral to prolong FES pedaling.

Functional electrical stimulation for chronic heart failure: A meta-analysis

IntroductionWe conducted a meta-analysis of randomized, controlled trials of combined electrical stimulation versus conventional exercise training or placebo control in heart failure patients. MethodsA systematic search was conducted of Medline (Ovid) (1950–September 2011), Embase.com (1974–September 2011), Cochrane Central Register of Controlled Trials and CINAHL (1981–September 2011). The search strategy included a mix of MeSH and free text terms for the key concepts heart failure, exercise training and functional electrical stimulation (FES). ResultsFES produced inferior improvements in peak VO2 when compared to cycle training: mean difference (MD) −0.32ml.kg−1.min−1 (95% C.I. −0.63 to −0.02ml.kg−1.min−1, p=0.04), however FES elicited superior improvements in peak VO2: MD 2.30ml.kg−1.min−1 (95% C.I. 1.98 to 2.62ml.kg−1.min−1, p<0.00001); and six minute walk distance to sedentary care or sham FES; MD 46.9m (95% C.I. 22.5 to 71.3m, p=0.0002). There was no difference in change in quality of life between cycling and FES, but FES elicited significantly larger improvements in Minnesota Living with Heart Failure score than placebo or sham treatment; MD 1.15 (95% C.I. 0.69 to 1.61, p<0.00001). Moreover, the total FES intervention hours were strongly correlated with change in peak VO2, (r=0.80, p=0.02). ConclusionsPassive or active exercise is beneficial for patients with moderate to severe heart failure, but active cycling, or other aerobic/resistance activity is preferred in patients with heart failure who are able to exercise, and FES is the preferred modality in those unable to actively exercise. The benefits of FES may however, be smaller than those observed in conventional exercise training. Aggregate hours of electrical stimulation therapy were associated with larger improvements in cardio-respiratory fitness.

Is transcutaneous peroneal stimulation beneficial to patients with chronic stroke using an ankle-foot orthosis? A within-subjects study of patients’ satisfaction, walking speed and physical activity level

The aim of this study was to evaluate whether community-dwelling chronic stroke patients wearing an ankle-foot orthosis would benefit from changing to functional electrical stimulation of the peroneal nerve. In 26 community-dwelling chronic (> 6 months post-onset) patients after stroke, their ankle-foot orthosis was replaced by a surface-based functional electrical stimulation device (NESS L300). Comfortable walking speed over 10 m was measured at baseline with the ankle-foot orthosis and after 2 and 8 weeks with both ankle-foot orthosis and functional electrical stimulation. The level of physical activity was assessed with a pedometer, and patients' satisfaction was assessed with a questionnaire at baseline and at week 8 regarding ankle-foot orthosis and functional electrical stimulation, respectively. Ankle-foot orthosis and functional electrical stimulation were equally effective with regard to walking speed and activity level. The participants were more satisfied with functional electrical stimulation than with their ankle-foot orthosis regarding the effort and stability of walking, quality of the gait pattern, walking distance, comfort of wearing and appearance of the device. The patients judged functional electrical stimulation superior to their ankle-foot orthosis, but measurements of walking speed and physical activity could not objectify the experienced benefits of functional electrical stimulation. Other outcome measures focusing on the stability and effort of ambulation may objectify the perceived benefits of functional electrical stimulation in community-dwelling chronic stroke patients.

Functional Electrical Stimulation for a Dropped Foot

The purpose of this collective review is to study the techniques, usage, methods, and clinical results of functional electrical stimulation applied to the peroneal nerve in the treatment of dropped foot. When stimulation is applied through surface electrodes, clinical reports have documented the therapeutic and orthotic benefits of functional electrical stimulation. Clinical trials are now being undertaken in which implantable electrodes are being used to stimulate the peroneal nerve in patients with dropped foot.

Functional electrical stimulation for upper limb strengthening in traumatic quadriplegia.

The hypothesis of this study was that the functional electrical stimulation (FES)-assisted exercise of partially paralyzed arm muscles would result in significantly greater muscle strength in the arms of spinal cord injured quadriplegics than equal periods of conventional isotonic exercise. Single muscles were studied in seven subjects in a crossover design consisting of equal periods of FES-assisted exercise and conventional exercise. It was concluded that for these subjects using this exercise regime, neither FES-assisted exercise nor conventional exercise produced improvements in maximum voluntary force that were either statistically or functionally significant. The results, although disappointing, have helped these subjects to be more realistic about the potential therapeutic benefits of FES.