Use Of Functional Electrical Stimulation Research Articles

Use of Functional Electrical Stimulation to Augment Traditional Orthopaedic Surgery in Children With Cerebral Palsy

The purpose of this study was to compare the functional outcomes of traditional lower extremity orthopaedic surgery to more limited surgery augmented with functional electrical stimulation (FES) applied while walking. Seventeen ambulatory children with cerebral palsy participated in this prospective pretest–posttest control group study. The surgical group (nine subjects) underwent traditional orthopaedic procedures. The FES group (eight subjects) underwent placement of percutaneous intramuscular FES electrodes and limited orthopaedic surgical procedures. Postoperatively, they were provided with an FES home walking program. One year after intervention, all children (combined data) showed improvements in passive range of motion, gait spatiotemporal parameters, and gross motor function (P < 0.05). No differences were seen between groups before or after intervention. The FES group underwent 4.5 fewer ablative procedures per child than the surgical group. These results suggest that FES in combination with more limited surgery may provide similar functional gains with fewer ablative procedures than traditional orthopaedic surgery.

Functional Electrical Stimulation For Walking In Paraplegia: 17-Year Follow-Up Of 2 Cases

Objective: To assess the safety and effectiveness of long-term use of functional electrical stimulation (FES) for exercise, standing, and walking in individuals with paraplegia, using percutaneous intramuscular wire electrodes.Design: Case study with more than 1 7 years of follow-up.Setting: Institutional rehabilitation practice.Study Participants: Two long-term (17 years) volunteer participants with paraplegia who were able to stand and walk using FES.Intervention: Chronically indwelling percutaneous intramuscular wire electrodes connected to a portable microprocessor-controlled stimulator were used to exercise muscles while controlling trunk, hips, knees, and ankles and develop activation patterns to produce standing and walking.Main Outcome Measures: Clinical complications, electrode performance and survival probability, and functional performance.Results: The most noted clinical complications included localized inflammation at the electrode site and superficial infection that responded well to topical and oral antibiotic treatment. The change from coil-wire electrodes, with a survival of 35% after 1 year, to double-helix electrodes improved electrode survival to 80% at 1 year and 48% at 5 years. Maintenance of the multichannel percutaneous FES walking system required replacement of an average of 2 electrodes every 6 months. Participants were able to use their system for independent exercise and standing and for walking with standby assistance.Conclusion: Although the FES system was devised as a temporary means of achieving functional activation until permanent means could be achieved, it was found to be effective and relatively safe for more than 17 years. Two long-time users of the system had no adverse effects to their skeletal system. The most common problems were daily care of electrodes at exit sites, frequent irritation of the skin around electrodes, and replacement of failed electrodes. The percutaneous system has the potential for short-term rehabilitation in individuals with incomplete paraplegia or stroke.Spinal Cord Med. 2003;26:86-91

Functional Electrical Stimulation of Bladder and Bowel in Spinal Cord Injury

The purpose of this collective review is to examine the use of functional electrical stimulation for incontinence. The Finetech-Brindley bladder system enhances voiding through stimulation via electrodes implanted around the ventral sacral roots. Detrusor hyperreflexia is eliminated through complete dorsal rhizotomy, which results in loss of reflex defecation and reflex erection/reflex lubrication. Consequently, a new system is being devised in which functional electrical stimulation for incontinence in spinal cord injury can be achieved without dorsal rhizotomy.

Use of functional electrical stimulation in the lower extremities of incomplete spinal cord injured patients.

After a program of therapeutic electrical stimulation, 3 groups of incomplete spinal cord injured (SCI) patients were identified, those in whom an improvement of both voluntary and stimulated muscle force was observed, those with an increase in stimulation response only, and patients in whom no effect of electrical stimulation training could be recorded. As it is difficult to predict the outcome of the electrical stimulation rehabilitation process, a diagnostic procedure was developed to predict soon after accidents which incomplete SCI patients are candidates for permanent use of a functional electrical stimulation (FES) orthotic aid. The candidates for chronic use of FES are patients with weak ankle dorsiflexors and sufficiently strong knee extensors. These patients are equipped with a single channel peroneal stimulator augmenting dorsiflexion and knee and hip flexion in a total lower limb flexion response. By applying FES to the ankle plantar flexors, the swing phase of walking can be significantly shortened and faster walking obtained.

Ankle, knee, and hip moments during standing with and without joint contractures: simulation study for functional electrical stimulation.

Joint contractures have been one of the contraindications for use of functional electrical stimulation for standing in paraplegic patients. A simulation study using a three-segment link mechanical model of the human body was performed to calculate the muscle moments at the ankles, knees, and hips during standing with and without having joint contractures. The knee and hip angles were varied in 5 degrees increments, whereas the ankle angles were varied in 1 degree increments. It was assumed that energy efficient posture was obtained with the least sum of the squared moments of the ankles, knees, and hips joints by the muscles. Ankles at 5 degrees of dorsiflexion, knees at 0 degrees, and hips at 15 degrees of extension resulted in the most energy efficient posture without joint contractures. The muscle moments increased with the increase in angle of contractures. The joint contractures at ankle angles > or = 6 degrees of plantar flexion, knee angles > or = 20 degrees of flexion, and/or hip angles > or = 20 degrees of flexion produce a potentially unstable posture. These findings suggest that some degree of joint contractures can be tolerated in paraplegic patients using functional electrical stimulation for standing.

Arterial supply of the latissimus dorsi muscle: A comparative study in human, sheep, dog, and pig

AbstractThe latissimus dorsi muscle (LD) has been the subject of numerous studies, especially because of its variety of possible applications in plastic and reconstructive surgery.The clinical use of functional electrical stimulation (FES) and cardiomyoplasty has raised completely new questions in recent years. It was the aim of our study to find an optimal model for animal experiments for this cardiosurgical method, in which the LD is completely removed from its origin and transferred into the thorax. For this purpose, we compared the LD's arterial supply in animals used in experimental surgery, the sheep, dog, and pig, with the LD's supply in human.For studying the arteries of the LD macroscopically and by X‐ray, we used an injection solution of latex and barium sulfate. After injection of the solution the vascularization was photographically documented. Subsequently, the muscle was detached from the neurovascular pedicle and prepared for radiological examination of the arterial vascularization.The planimetric computer‐assisted identification of the various areas supplied by arterial branches was based on these radiograms. In order to also assess the weight of the supplied parts, the muscles were gravimetrically analyzed.The study showed that the blood supply in pig is very similar to that of man. This species, therefore, would be best suited for experimental cardiomyoplasty. © 1994 Wiley‐Liss, Inc.

Reduction of seating pressure using FES in patients with spinal cord injury. A preliminary report.

The aim of this study was to investigate the use of functional electrical stimulation (FES) as a means of pressure sore prevention in seated spinal cord injured (SCI) subjects. Nine SCI subjects took part in tests in which electrical stimulation was applied to the quadriceps with the lower legs restrained. Ischial pressures were measured during periods of quiet sitting and FES application. A strain gauged lever arm was used to measure the knee moment during quadriceps stimulation. The average pressure drop at the right and left buttocks was 44 mmHg and 27 mmHg respectively. In general the greatest reductions occurred in subjects with larger knee moments; however, there was no direct relationship between the pressure reduction obtained and the quadriceps strength. This form of FES may be useful as a prophylactic aid in the management of pressure sores in SCI subjects.

Evaluation of Functional Electrical Stimulation for an Incomplete Spinal Cord Injured Patient

Summary The incidence of people surviving with incomplete spinal cord injury is increasing owing to the use of vehicle seat-belts and improved early care. However, the value of the use of functional electrical stimulation (FES) in these subjects was apparently not assessed. This paper describes a treatment report in which FES was used on a female subject with an incomplete spinal cord injury four years after she had completed her rehabilitation in a spinal injury unit. After one year of using FES she had gained enough voluntary strength in her lower limbs to be able to discard her knee-ankle-foot orthoses and to stand and walk independently using a walking frame. Her spasms also reduced, she enjoyed greater independence, and her psychological state and quality of life improved. This study suggests that a research trial on the efficacy of FES in a wide range of subjects with incomplete spinal cord injury is indicated.

The use of functional electrical stimulation to assist gait in patients with incomplete spinal cord injury.

The use of FES (functional electrical stimulation) for gait reproduction in six patients with spinal cord injury is described. Following a detailed neuromuscular assessment the patients commenced a muscle conditioning programme using electrical stimulation applied via surface electrodes. Once patients were strong enough to stand, gait synthesis was initiated in the laboratory utilizing a programmable electrical stimulator. When a satisfactory gait pattern had been achieved, patients used their portable stimulator at home. All six patients became able to stand and walk using the FES system and completed the home phase of the programme. Three patients continue to use the system at home for exercise and walking; the other patients have discontinued using the system, preferring a wheelchair or their original orthoses. We conclude that FES-assisted walking is feasible in patients with incomplete spinal cord injury, even with severe motor loss. Further advances in technology are needed for the system to become applicable to a larger number of patients.

A method for evaluating the selectivity of electrodes implanted for nerve simulation

The scale of stimulating electrodes possible for use in functional electrical stimulation to restore motor and sensory function is rapidly approaching that of individual neurons. Although the electrodes may approach the dimensions of single nerve cells, it is unclear if the region of excitation elicited by each electrode will be correspondingly small. Previous techniques for evaluating this have either been tedious or have lacked the resolution necessary. This paper describes a method that uses the refractory interaction of the compound action potentials elicited by a stimulus pulse pair, along with high-resolution recording of those potentials, to achieve measurements of the selectivity of stimulation down to the scale of a few axon diameters. The feasibility of this technique is demonstrated in sciatic nerves of frogs (Rana Catesbiana) acutely implanted with a sapphire electrode array.

Functional Electrical Stimulation in Lower Extremity Orthoses in Hemiplegia

An overview is given of the present use of Functional Electrical Stimulation (FES) based lower extremity orthoses in therapy procedures in hemiplegia. In one specialized FES center in Ljubljana, Slovenija, 63% of all stroke patients were treated with some sort of FES therapy in combination with classical therapies, representing around 10% of the total hemiplegic population of the nation. Verticalization, i.e., the initiation of gait and lessening of gait anomalies, has been achieved by two to three weeks of therapy using a six-channel microprocessor controlled stimulator. For orthotic purposes, during activities of daily living only various types of single channel peroneal stimulators have been used so far. Implantable versions of the stimulator have provided much better performance. The heuristic principle of synthesis of gait by FES presently in use should be replaced by a more versatile microprocessor controller based on a more complete mathematical model of the afflicted locomotor system in subjects w...

Control of functional electrical stimulation with extended physiological proprioception

The use of functional electrical stimulation (FES) of muscle for paraplegic locomotion, or grasp augmentation in tetraplegia, is limited by the variability in muscle response to stimulation as a result of several external and internal factors. Previous approaches to this problem have used position-servo controllers, which have been shown to function satisfactorily in the laboratory. However, such systems will fail should obstacles be encountered or should the stimulation hardware develop a fault. To prevent such potentially dangerous failures some form of sensory feedback is required. This paper describes the first application of a technique known as extended physiological proprioception (EPP) to the control of FES to compensate for muscle response variability and provide proprioceptive feedback via the appropriate sensory pathways. In the experimental system described, a paraplegic subject controlled the extension of his paralysed knee by shoulder protraction. A Bowden cable linked the two joints, and a dynamometer in this cable was used to derive the control signal for a computer-controlled stimulator which delivered surface stimulation to the quadriceps muscle group. Modelling and parameter identification were performed by analysis of the step response, and the controller was designed from consideration of the root locus. The advantages of the system, in terms of improved proprioceptive feedback and reduced limb-positioning error were assessed in a test of joint positioning accuracy with vision occluded. The EPP system showed improvements over both open and closed-loop position-servo controllers.

Use of functional electrical stimulation in the rehabilitation of patients with incomplete spinal cord injuries

When patients enter the Rehabilitation Centre a therapeutic electrical stimulation programme is immediately initiated. Three groups of patients were identified: (i) those in whom an improvement of both voluntary and stimulated muscle force was observed, (ii) those with an increase in stimulation response only, and (iii) patients in whom no effect of electrical stimulation training could be recorded. Isometric measurement of voluntary and stimulated knee joint torque revealed that in a great number of patients one leg was severely paralysed while the other leg was under sufficient voluntary control. Unilateral two-channel stimulation of knee extensors and the peroneal nerve was proposed as an orthotic aid for this group of patients. Exaggerated extensor tone was observed by assessment of spasticity around the knee joint. A two-channel peroneal stimulator was found to be a useful approach in order to inhibit this tone and thereby help the patients to initiate a step.

Evaluation of the effects of functional electrical stimulation on muscle power and spasticity in spinal cord injury patients

Nineteen paraplegic patients were entered into a trial to evaluate the use of functional electrical stimulation (FES) as a practical and reliable method of aiding standing. The clinical study used commercially available muscle stimulators, in contrast to the many previously reported case studies where prototype equipment has been used. This paper examines the effect of FES on muscle strength and spasticity in the paretic quadriceps muscle of paraplegic patients and demonstrates that only five of the subjects in the study exhibited an increase in muscle power of the stimulated quadriceps muscle, and that change in the level of spasticity, with varying patterns, occurred in all but two patients.

Practical low cost stand/sit system for midthoracic paraplegics

The use of functional electrical stimulation (FES) to enable paraplegics to stand is not new or indeed difficult to undertake under laboratory conditions. However, there are substantial problems to overcome before such systems can be used routinely by patients without professional supervision. The overriding consideration has to be one of safety, i.e. the system must be ‘fail safe’. Secondly, the system must be quick and easy to use in a wide variety of locations, otherwise it will not provide any increase in function. Finally, it must be inexpensive enough to be available to a large number of paraplegics. The primary aim of our work was to provide such a system to enable mid-thoracic lesion paraplegics to stand wherever they wish. This involved the development of a microprocessor-based stimulator to enable the stimulating envelope to be individually tailored to a given patient's requirements and the provision of closed loop control to minimize fatigue. A folding standing frame was also designed which replaces the arm rests on a standard wheelchair. Using this system, the user is able to stand within 30 s of stopping and can remain standing for up to 10 min. Cosmetic calipers (knee-ankle-foot orothoses) are also being used for paraplegics who require to stand for longer periods. It is hoped that such a system will provide stable standing for a large number of paraplegics at a unit cost of approximately £750.

Functional electrical stimulation in incomplete tetraplegia

This paper describes the use of functional electrical stimulation in the management of a 37-year-old male patient who had sustained an incomplete tetraplegia, below C5 on the right and below C7 on the left. The patient's training programme is outlined, with particular reference to gait reeducation.

Functional Electrical Stimulation of the Extremities in the Neurological Patient: A Review

The use of functional electrical stimulation (FES) in the treatment of neurological conditions has an extensive history, one that has seen great advances in recent years. Developments in this area of rehabilitation are outlined and avenues for future research and clinical study suggested. The application of FES to the neurological patient may be of considerable benefit alongside conventional facilitatory/inhibitory techniques. The physiotherapist is ideally placed to participate in studies of this modality to determine its role in clinical practice.

Computer-controlled 22-channel stimulator for limb movement.

The Nucleus multichannel implantable hearing prosthesis (Nucleus Ltd., Sydney, Australia) has been modified by computer programming (MOCO, Inc., Scituate, Mass.) into a 22-channel neural stimulator for use in functional electrical stimulation (FES). Individual or multiple channels can be sequenced and adjusted for their individual pulse amplitude, width and frequency so that activation of single and multiple nerves can be achieved. Anesthetized rabbits' sciatic nerve branches (lateral and medial) were stimulated to produce single, or co-contraction at the ankle and simultaneous bilateral joint movements. The spiral (helix) electrode was also found suitable in these experiments. In planning for the stimulator's use in paraplegic subjects, information was obtained for human lower extremity peripheral nerves. In 9 patients undergoing lower extremity amputation, threshold and maximal levels of stimulation plus nerve diameters were obtained on 21 nerves. The design for the wearable ambulation unit to control the 22-channel stimulator and electrode tresses with helix electrodes has been completed.

The use of functional electrical stimulation for rehabilitation of spinal cord injured patients.

Computer-directed functional electrical stimulation that employs closed-loop (feedback) technology has been used for rehabilitation of spinal cord injured (SCI) patients. This paper summarizes the most recent developments in our laboratory. First, the design of an adaptive control system is described, and its resultant controllability is reviewed. Second, our current results with the isokinetic leg trainer are summarized with respect to muscular strength and mass and cardiovascular changes in paraplegics and quadriplegics. Third, our current results with the exercise bicycle ergometer are summarized regarding muscular endurance and cardiovascular changes in control, paraplegic, and quadriplegic subjects. Fourth, impact vibration is reviewed as a potential technique to reverse disuse osteoporosis, and clinical case studies are cited. Fifth and finally, thermoregulatory studies are presented for the first time on control, paraplegic, and quadriplegic subjects. Conclusions are drawn regarding mechanisms and recommendations made for exercise of SCI subjects in hot and humid environments.