Showing papers on "Functional electrical stimulation published in 1989"
Book•
31 Jan 1989
TL;DR: This chapter discusses Muscle Restrengthening and Patient Conditioning, FES Ambulation Program in Incomplete SCI Patients, and FES-Ass Walk-ing in Complete SCI patients.
Abstract: Introduction. Muscle Restrengthening and Patient Conditioning. Influence of Electrical Stimulation on Spas-ticity in Spinal Cord Injured Patients. Restoration of Standing. FES Ambulation Program in Incomplete SCI Patients. FES-Assisted Walk-ing in Complete SCI Patients. Index. 208 pp., 7x10, 1989, ISBN-0-8493-4529-4. Features:
460 citations
TL;DR: It is demonstrated that axons in peripheral nerves can be irreversely damaged by 8–16 hours of continuous stimulation at 50 Hz, and the extent to which these axons may subsequently regenerate is uncertain.
Abstract: Helical electrodes were implanted around the left and right common peroneal nerves of cats. Three weeks after implantation one nerve was stimulated for 4–16 hours using charge-balanced, biphasic, constant current pulses. Compound action potentials (CAP) evoked by the stimulus were recorded from over the cauda equina before, during and after the stimulation. Light and electron microscopy evaluations were conducted at various times following the stimulation. The mere presence of the electrode invariably resulted in thickened epineurium and in some cases increased peripheral endoneurial connective tissue beneath the electrodes. Physiologic changes during stimulation included elevation of the electrical threshold of the large axons in the nerve. This was reversed within one week after stimulation at a frequency of 20 Hz, but often was not reversed following stimulation at 50–100 Hz. Continuous stimulation at 50 Hz for 8–16 hours at 400 μA or more resulted in neural damage characterized by endoneurial edema beginning within 48 hours after stimulation, and early axonal degeneration (EAD) of the large myelinated fibers, beginning by 1 week after stimulation. Neural damage due to electrical stimulation was decreased or abolished by reduction of the duration of stimulation, by stimulating at 20 Hz (vs. 50 Hz) or by use of an intermittent duty cycle. These results demonstrate that axons in peripheral nerves can be irreversely damaged by 8–16 hours of continuous stimulation at 50 Hz. However, the extent to which these axons may subsequently regenerate is uncertain. Therefore, protocols for functional electrical stimulation in human patients probably should be evaluated individually in animal studies.
180 citations
TL;DR: A multichannel functional electrical stimulation (FES) system for the restoration of quadriplegic upper extremity function is described and versatile volitional control is realized by controlling the memory allocation of the stored stimulation data by voluntary respiratory signals.
Abstract: A multichannel functional electrical stimulation (FES) system for the restoration of quadriplegic upper extremity function is described. The system is composed of a personal computer, peripheral electronic circuits, CRT display and respiratory sensors for volitional control by the patient, and percutaneous electrodes. In this system, versatile volitional control is realized by controlling the memory allocation of the stored stimulation data by voluntary respiratory signals, and sophisticated fine control of the fingers, wrists, and elbow is realized by creating multichannel stimulation data from recorded myoelectric activities of normal subjects during movements of the upper limb. >
179 citations
TL;DR: The hybrid assistive system presented here is a combination of multichannel surface FES and self-fitting modular orthosis and the control system is nonnumerical and based on artificial reflexes.
Abstract: Two approaches are currently applied for motor rehabilitation of paralyzed humans: functional electrical stimulation (FES) and mechanical bracing. Both assistive systems have limited application due to several factors. The combination of FES and an externally powered and controlled brace is called a hybrid assistive system (HAS). The HAS presented here is a combination of multichannel surface FES and self-fitting modular orthosis. Energy expenditure and a reduction of force load on the upper extremities are criteria for the efficacy of HAS. The control system of HAS is nonnumerical and based on artificial reflexes. >
129 citations
TL;DR: The use of electromyographic (EMG) pattern analysis to provide upper-motor-neuron paraplegics with patient-responsive control of FES (functional electrical stimulation) for the purpose of walker-supported walking is discussed.
Abstract: The use of electromyographic (EMG) pattern analysis to provide upper-motor-neuron paraplegics with patient-responsive control of FES (functional electrical stimulation) for the purpose of walker-supported walking is discussed. The system described uses above-lesion surface EMG signals to activate standing and walking functions in a patient-responsive manner. This system was been experimentally applied to paraplegics since early 1982. Below-lesion response-EMG control from the stimulated sites was added in 1987 to regulate stimuli levels in the face of fatigue. Although transcutaneous FES alone is being used the system is applicable in principle to implantable FES systems. >
105 citations
TL;DR: A percutaneous intramuscular electrode developed for controlling paralyzed extremities by functional electrical stimulation (FES) is discussed and it is shown that stable and reliable FES was achieved for a long time.
Abstract: A percutaneous intramuscular electrode developed for controlling paralyzed extremities by functional electrical stimulation (FES) is discussed. The electrode was made of a Teflon-coated 19-strand rope wound from ultrafine SUS 316L stainless steel wires and was helically coiled for high flexibility. Because of low percentages of electrode failure in the body, stable and reliable FES was achieved for a long time. >
102 citations
TL;DR: 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.
83 citations
TL;DR: It was concluded that muscle fatigue was the functionally limiting factor for the quadriplegic patient, and application of the system for walking exercise should be preceded by a physical conditioning program of functional electrical stimulation.
Abstract: The purpose of this study was to determine whether commercially available electrical muscle stimulators could provide functional ambulation exercise for the spinal cord injured individual. Commercially available electrical muscle stimulators were used for functional electrical stimulation and interfaced with reciprocating gait orthoses so that a new system has been developed. Advantages of the system include commercially available subsystems and subsystems for applications such as gait training. The system involves six electrical stimulation units worn on a belt; controlled by remote switches; and interfacing to electrodes placed over the quadriceps femoris, hamstring, and gluteal muscle groups of each leg. Four electrical stimulation units (for quadriceps femoris muscle stimulation) function primarily for stand-up and sit-down activities. Two other units (for stimulation of the hip extensor muscles) function primarily for ambulation. The system is described for use with a C7-level quadriplegic individual. The patient successfully performed over 20 repetitions of stand-up and sit down exercises with the system. An average walking distance of about 0.8 km was routinely traversed at velocities ranging from 1.2 to 2.0 km per hour. It was concluded that muscle fatigue, rather than battery power, was the functionally limiting factor for the quadriplegic patient. A recommendation is that application of the system for walking exercise should be preceded by a physical conditioning program of functional electrical stimulation. Specific medical criteria should be satisfied prior to formally prescribing the system for an individual. Finally, the steps involved in the writing of the walking system prescription are outlined.
27 citations
TL;DR: The system has been evaluated on a T-5 level paraplegic individual who sustained a motor complete lesion (Frankel Class B) of the spinal cord over seven years ago and it is emphasized that successful EMS-RGO walking exercise must be preceded by a physical conditioning programme of active physical therapy.
26 citations
01 Jan 1989
25 citations
TL;DR: Results illustrate how the present control system, which integrates the paralyzed person and electrical stimuli by signature analysis of EMG signals, yields walker-supported walking by paraplegics in a manner that recognizes and executes the patient's intended limb functions and compensates for muscle fatigue.
Abstract: The authors describe the use of electromyographic (EMG) signatures for controlling functional electrical stimulation (FES) in upper-motor-neuron paraplegics to enable them to walk with the help of a walker. It was shown that the above-lesion EMG control and below-lesion response-EMG control serve complementary and crucial roles in total FES control. It was also shown that below-lesion response-EMG control of stimulation levels can play a crucial role in FES, regardless of above-lesion EMG control. Actual patient-test-results using the above EMG controls are discussed. These results illustrate how the present control system, which integrates the paralyzed person and electrical stimuli by signature analysis of EMG signals, yields walker-supported walking by paraplegics in a manner that recognizes and executes the patient's intended limb functions and compensates for muscle fatigue. >
TL;DR: The FES treatment induced a reduction in the antagonist co-contraction level associated with spasticity and these findings further support the use of FES for neurological retraining after a cerebrovascular accident.
Abstract: This study was undertaken to test the effects of a functional electrical stimulation (FES) training programme on the co-contraction level of spastic hemiparetic patients during a maximal speed forearm extension movement. Twelve males participated in 24 sessions of FES treatments applied to the triceps and biceps of the hemiparetic limb. The pattern of electrical stimulation was adjusted individually, after mathematical modelling of the EMG parameters, obtained at the execution of the task by the nonaffected limb. Pre- and posttest measurements included movement amplitude, time to maximal movement amplitude and peak amplitude of EMG activity in the triceps and biceps. All parameters were modified significantly (p < .01) following FES and the triceps to biceps ratio of EMG activity was also changed (p < .01). The FES treatment induced a reduction in the antagonist co-contraction level associated with spasticity and these findings further support the use of FES for neurological retraining after a cerebrovasc...
TL;DR: 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.
01 Jan 1989
TL;DR: The findings from some recent electrophysiological studies of human muscle in relation to functional electrical stimulation (FES) are discussed and the importance of considering muscle fatigue is emphasised.
Abstract: The effects of electrical stimulation on muscle are not fully known. This review discusses the findings from some recent electrophysiological studies of human muscle in relation to functional electrical stimulation (FES) and emphasises the importance of considering muscle fatigue. Further laboratory and clinical studies are needed to provide a rational basis for selecting appropriate stimulation parameters when using FES.
09 Nov 1989
TL;DR: A description of commands for controlling the paralyzed upper extremities by functional electrical stimulation (FES) is given and Respiration was used for restoration of totally paralyzed upper limbs in C4 quadriplegic patients.
Abstract: A description of commands for controlling the paralyzed upper extremities by functional electrical stimulation (FES) is given. Respiration was used for restoration of totally paralyzed upper limbs in C4 quadriplegic patients. The paralyzed hand in C6-7 quadriplegics was volitionally controlled by wrist movements of the patient. EMG control of the paralyzed upper limbs is also described. >
09 Nov 1989
TL;DR: Preliminary results demonstrate that the EMG signal contains useful information about the state of electrically stimulated muscle that may be useful in functional electrical stimulation (FES) applications, but that significant measurement problems must be solved before accurate, selective EMG recordings in the presence of surface stimulation are possible.
Abstract: The authors have measured RMS EMB (electromyogram) and mean EMG frequency as a function of simulated muscle force in isometric quadriceps muscle of able-bodied human subjects using an artifact-suppressing surface stimulator and blanking EMG amplifier Preliminary a results demonstrate that the EMG signal contains useful information about the state of electrically stimulated muscle that may be useful in functional electrical stimulation (FES) applications, but that significant measurement problems must be solved before accurate, selective EMG recordings in the presence of surface stimulation are possible Also, the nature of the EMG signal for stimulated muscle in nonisometric conditions needs to be explored >
TL;DR: Various methods for minimizing fatigue have been proposed and are presently discussed, including fibre type conversion as a result of chronic low frequency conditioning stimulation, sequential stimulation, optimization of stimulation parameters and the use of hybrid orthoses.
Abstract: Interest in the possibility of using electrically stimulated muscular contractions in rehabilitation medicine is increasing. Progress is impeded by the phenomenon of fatigue which impairs effectiveness and consistency of contractions. Various methods for minimizing fatigue have been proposed and are presently discussed. These include fibre type conversion as a result of chronic low frequency conditioning stimulation, sequential stimulation, optimization of stimulation parameters and the use of hybrid orthoses.
09 Nov 1989
TL;DR: A portable percutaneous, intramuscular-electrode-type, 30-channel electrical stimulation system has been developed which has the capability of both functional electrical stimulation (FES) and therapeutic Electrical stimulation (TES).
Abstract: A portable percutaneous, intramuscular-electrode-type, 30-channel electrical stimulation system has been developed which has the capability of both functional electrical stimulation (FES) and therapeutic electrical stimulation (TES). This system was developed with an emphasis on flexibility, which makes it easily adaptable to various patients, easy to operate, and durable. The control sensors will be further enhanced in order to make effective use of the patients's remaining functions. >
TL;DR: It is demonstrated 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.
Abstract: 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
09 Nov 1989
TL;DR: A study of the effects of a program of functional electrical stimulation on the ambulation of a subject with spastic diplegic cerebral palsy is reviewed and improvements in range of motion, distance, velocity, and torque are documented.
Abstract: A study of the effects of a program of functional electrical stimulation on the ambulation of a subject with spastic diplegic cerebral palsy is reviewed. Knee joint motion, ankle joint motion, and knee joint torque were measured. Improvements in range of motion, distance, velocity, and torque were documented in this subject. Spasticity reduction and posture improvement were also observed. >
09 Nov 1989
TL;DR: A method is proposed for achieving voluntary rolling over of the paralyzed body by functional electrical stimulation (FES) that may be more practical and efficient than the use of an expensive patient care robot in order to prevent bedsores (decubitus).
Abstract: A method is proposed for achieving voluntary rolling over of the paralyzed body by functional electrical stimulation (FES). Multichannel EMG recordings were made of the rolling-over motion of normal subjects in order to determine which muscles should be the target of FES. It is believed that the proposed method may be more practical and efficient than the use of an expensive patient care robot in order to prevent bedsores (decubitus). >
09 Nov 1989
TL;DR: In this paper, a mathematical model of the human locomotor apparatus which provides the kinematics on the basis of muscular torques is presented, and the results of simulation and integration of the model in the general problem of multichannel implanted stimulation are illustrated.
Abstract: The authors describe criteria for choosing the best stimulation pattern to be used in walking restoration by FES (functional electrical stimulation). For this purpose, a mathematical model of the human locomotor apparatus which provides the kinematics on the basis of muscular torques is presented. The results of simulation and the integration of the model in the general problem of multichannel implanted stimulation are illustrated. >
09 Nov 1989
TL;DR: In this article, a general-purpose control scheme that combines a short leg brace and functional electrical stimulation (FES) is described to avoid quadriceps fatigue with a minimum of constraint to the leg.
Abstract: A general-purpose control scheme that combines a short leg brace and functional electrical stimulation (FES) is described. This combined or hybrid system is designed to avoid quadriceps fatigue with a minimum of constraint to the leg. The structure of the brace is described, and the results of preliminary patient tests are reported, showing improved response as compared with a conventional system. >
09 Apr 1989
TL;DR: Functional electrical stimulation has been used in several recent studies to help hemiplegics regain control of limb movement and experiments were conducted to define the most repeatable and pertinent small set of EMG parameters.
Abstract: Functional electrical stimulation (FES) has been used in several recent studies to help hemiplegics regain control of limb movement. The EMG (electromyographic) patterns associated with the movement of the unafflicted limb are used to obtain the FES pattern, which is applied to the afflicted limb to cause similar movement during the training period. To refine the technique further, experiments were conducted to define the most repeatable and pertinent small set of EMG parameters. Preliminary results from consecutive arm movements of three healthy subjects are presented. >
09 Nov 1989
TL;DR: The use of an EMG monitor is believed to increase the efficacy of the HOS by reducing muscle fatigue, increasing safety, and reducing the use of external power.
Abstract: Motor restoration of paralyzed humans using a hybrid orthotic system (HOS) known as artificial reflex control is discussed. Artificial reflex control is a nonnumerical procedure requiring sensory information. The sensory information for a hybrid brace combining functional electrical stimulation and an externally controlled modular brace consists of ground force record, angular displacement from the gravity line, joint angles and electromyogram (EMG) signals. Sensors for the HOS are described. The use of an EMG monitor is believed to increase the efficacy of the HOS by reducing muscle fatigue, increasing safety, and reducing the use of external power. External power is used only in that phase of the gait in which muscular function is not adequate. >
09 Nov 1989
TL;DR: The standing-up movement induced by FES was easily achieved after several exercises, and the standing position could be kept very stable and the patient was able to control locomotion.
Abstract: A description is given of the control of standing-up movement from a wheelchair and locomotion for paraplegics by functional electrical stimulation (FES). In order to determine stimulation patterns of lower extremity muscles, activities of 21 muscles were analyzed in normal subjects by averaging their EMGs (electromyograms). On the basis of this analysis, standard stimulation patterns for the lower extremity muscles were programmed and stored in a 64-channel portable FES system. The standing-up movement induced by FES was easily achieved after several exercises, and the standing position could be kept very stable. Using hand switches attached to a walker, the patient was able to control locomotion. >
09 Nov 1989
TL;DR: Functional electrical stimulation was investigated as a method for restoration or improvement of gait in spinal-cord-injured subjects, using surface electrical stimulation using commercial stimulators.
Abstract: Functional electrical stimulation (FES) was investigated as a method for restoration or improvement of gait in spinal-cord-injured subjects, using surface electrical stimulation. Using commercial stimulators, walking and posture control were studied in a T-6 complete paraplegic. Six channels of stimulation were used for walking. The experimental results are presented and discussed. >
09 Nov 1989
TL;DR: Multichannel functional electrical stimulation for restoring motor function of the disabled is described and Sensors for detecting control commands were developed after due consideration of daily activities of FES candidates.
Abstract: Multichannel functional electrical stimulation (FES) for restoring motor function of the disabled is described. The control strategy is based on simulating the morphology and function of the human motor system. Multichannel stimulation data were created from analytical results of averaged EMGs (electromyograms) during motion in normal subjects. Most of the paralyzed muscles were stimulated through percutaneously implanted electrodes according to the spatio-temporal sequence of stimulation data. Sensors for detecting control commands were developed after due consideration of daily activities of FES candidates. >