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Biomedical subjects

M R Popovic

Publications and source records attributed to M R Popovic.

6 recordsLinked to original sources
PubMed2006

Functional electrical therapy: retraining grasping in spinal cord injury.

OBJECTIVE: To determine the clinical efficacy of functional electrical therapy in the rehabilitation of grasping function for quadriplegics. STUDY DESIGN: Randomized intervention-versus-control trial. SETTING: Rehabilitation hospital for spinal cord injury in Toronto, Canada. METHODS: A total of 21 people with new spinal cord injuries ranging from C3 to C7 were randomly assigned to two groups: Control (N=9) and Intervention (N=12). The intervention was functional electrical therapy, which consisted of repetitive grasping exercises using a neuroprosthesis that applied surface electrical stimulation to the arm to generate and/or assist grasping movements. It was applied by registered Occupational Therapists in a clinical setting. Main outcome measures were: Functional Independence Measure (FIM), Spinal Cord Independence Measure (SCIM), and the Rehabilitation Engineering Laboratory Hand Function Test. Consumer perceptions of functional electrical therapy were assessed via qualitative interviews. RESULTS: Differences between the Control and Intervention groups could be observed although they are not significant due to an insufficient number of participants. Consumer perceptions were positive, including improved Activities of Daily Living and self-satisfaction. CONCLUSION: Functional electrical therapy has the potential to be an effective treatment modality to restore grasping function in quadriplegia. It can be implemented by occupational therapists in a clinical setting. Further research is required to establish suitable indications for participant selection. In addition, a larger number of participants is needed to demonstrate statistical significance of the Functional Electrical Therapy.

Adolescent↗
PubMed2005

Gait training regimen for incomplete spinal cord injury using functional electrical stimulation.

STUDY DESIGN: Case series, and repeated assessments of the same individuals. OBJECTIVE: To demonstrate the feasibility and efficacy of a multiweek intervention on walking function in people with chronic, incomplete spinal cord injuries. SETTING: Rehabilitation hospital for spinal cord injury (SCI) in Toronto, Canada. METHODS: A convenience sample of five subjects with chronic, incomplete SCI trained for 12-18 weeks using a new multichannel neuroprosthesis for walking. The following outcome measures were recorded throughout the training period: walking speed, step frequency and average stride length based on a 2-min walk test. Also identified were which walking aids and orthoses subjects preferred to use, and whether they employed a step-to or step-through gait strategy. Follow-up measurements of three subjects were made up to 10 weeks after treatment. RESULTS: All subjects demonstrated significant improvements in walking function over the training period. Four of the subjects achieved significantly increased walking speeds, which were due to increases in both stride length and step frequency. The fifth subject experienced a significant reduction in preferred assistive devices. Follow-up measurements revealed that two subjects walked slightly slower several weeks after treatment, but they still walked significantly faster than at the start of treatment. CONCLUSION: The gait training regimen was effective for improving voluntary walking function in a population for whom significant functional changes are not expected. This application of functional electrical therapy is viable for rehabilitation of gait in incomplete SCI.

Adult↗
PubMed2005

Dynamic force-sharing in multi-digit task.

BACKGROUND: Dynamic hand grasping implies sophisticated motor coordination. Most knowledge on motor synergies used in grasping is deduced from experiments based on static precision grip. This experiment was aimed at better understanding the mechanisms of finger force-sharing in an active, dynamic hand task under repetitive strain conditions. METHODS: A multi-digit task consisting of holding a cylinder with the digit tips, in which the thumb and the finger opposed each other, was investigated during repetitive unidirectional wrist flexion and extension cyclic motion. Finger and thumb forces and wrist angular position were simultaneously recorded during repetitive wrist motion against 0.3-0.6 Nm load in 10 healthy adults. FINDINGS: Load torques acting during wrist movements produced in-phase increases of the thumb and the finger forces with the wrist extension and the wrist flexion, respectively. Digit forces increased proportionally to the applied load. The alternating rise of thumb and finger forces changed instantaneously at the end of the flexion and extension phases of the movement, respectively. Six subjects predominantly used the index finger, two the middle finger, one the ring finger, and the remaining one used the small finger during wrist flexion against 0.6 Nm to perform the task. Variations among individual finger forces were negatively correlated during the phase of constant rotational velocity of the wrist flexion. Repeated measures ANOVA revealed that the percentage of individual finger contribution to the total fingers' force significantly varied during the wrist flexion (P<0.0001) and among wrist flexion cycles (P<0.0001) in each subject. INTERPRETATION: Variations in finger force-sharing among cycles were not necessitated by task dependent activities, as the task was identical. These findings indicated that motor coordination of repeated multi-finger task allowed redundant solutions in finger force-sharing. The force-sharing variation may reflect a minimal intervention principle of the central nervous system controlling only the goal-directed parameters and might help to prevent muscle fatigue in repetitive tasks through modulation of activity in multi-digit muscles.

Adult↗
PubMed2001

Functional electrical stimulation for grasping and walking: indications and limitations.

This review describes the state of art in the field of Functional Electrical Stimulation (FES) and its impact on improving grasping and walking functions in acute and chronic Spinal Cord Injured (SCI) patients. It is argued that during the early rehabilitation period the FES systems with surface stimulation electrodes should be used to assist training of hand and leg movements in SCI patients. Our clinical trials have shown that a number of acute SCI patients with impaired walking and grasping functions could improve these functions due to training with an adjustable FES system to the point that they finally did not need the FES system to carry out these tasks. Other acute SCI patients, who did not recover the desired function, were enabled to perform either walking or grasping with the FES assistance. We believe that the subjects who can perform grasping or walking with the help of FES, and still use the neuroprosthesis 6 months after being subjected to the FES training, should consider the FES system as a prosthetic device in Activities of Daily Living (ADL). Despite the significant technical progress achieved in the last 10 to 15 years in the FES field, there is a general consensus that these systems are not sufficiently advanced and that they need further development. The limited acceptance of the FES technology can be in part explained by the fact that it is not completely mature and that the patients still require daily assistance to use the FES systems. Nevertheless the present FES treatments combined with conventional occupational and physical therapy still remain the most promising approach in rehabilitating SCI patients. In this review, advantages and limitations of different FES systems that are used to restore grasping and walking functions are discussed.

Electric Stimulation Therapy↗
PubMed2001

A reliable gait phase detection system.

A new highly reliable gait phase detection system, which can be used in gait analysis applications and to control the gait cycle of a neuroprosthesis for walking, is described. The system was designed to detect in real-time the following gait phases: stance, heel-off, swing, and heel-strike. The gait phase detection system employed a gyroscope to measure the angular velocity of the foot and three force sensitive resistors to assess the forces exerted by the foot on the shoe sole during walking. A rule-based detection algorithm, which was running on a portable microprocessor board, processed the sensor signals. In the presented experimental study ten able body subjects and six subjects with impaired gait tested the device in both indoor and outdoor environments (0-25 degrees C). The subjects were asked to walk on flat and irregular surfaces, to step over small obstacles, to walk on inclined surfaces, and to ascend and descend stairs. Despite the significant variation in the individual walking styles the system achieved an overall detection reliability above 99% for both subject groups for the tasks involving walking on flat, irregular, and inclined surfaces. In the case of stair climbing and descending tasks the success rate of the system was above 99% for the able body subjects and above 96 % for the subjects with impaired gait. The experiments also showed that the gait phase detection system, unlike other similar devices, was insensitive to perturbations caused by nonwalking activities such as weight shifting between legs during standing, feet sliding, sitting down, and standing up.

Adult↗