Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology
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J Electromyogr Kinesiol · Oct 1999
Reduction in subluxation and improved muscle function of the hemiplegic shoulder joint after therapeutic electrical stimulation.
Seventeen hemiplegic patients with chronic shoulder subluxation secondary to a cerebrovascular accident (CVA) were divided into three groups, two of which were subjected to 6 weeks of therapeutic electrical stimulation (TES) for 15 minutes twice a day, in order to assess the effectiveness of the treatment in reducing subluxation, and in improving shoulder abduction function. The third group was used as a control (C group). After 6 weeks of electrical stimulation of the supraspinatus (S group) and deltoid (D group), a significant (p<0.05) reduction in subluxation was observed in both groups when compared to the C group. ⋯ In most of the TES-treated muscles, the interference pattern of EMG at maximum voluntary contraction increased. The amplitude of the EMG activity of the stimulated muscle also increased. Thus, we concluded that electrical stimulation therapy of the supraspinatus and the deltoid muscle is an effective treatment modality for shoulder subluxation and shoulder abduction function in hemiplegic patients.
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J Electromyogr Kinesiol · Feb 1999
Comparative StudyChanges in surface EMG parameters during static and dynamic fatiguing contractions.
The effect of contraction types on muscle fiber conduction velocity (MFCV), median frequency (MDF) and mean amplitude (AMP) of surface electromyography was examined in the vastus lateralis of 19 healthy male adults. The subjects performed knee extension both statically and dynamically until they were exhausted. The static contraction was a sustained isometric extension of the knee at a joint angle of 90 degrees with 50% of the maximum voluntary contraction (MVC) load. ⋯ On the other hand, MFVC during the dynamic contraction did not significantly change throughout the exercise. MDF decreased and AMP increased during both types of contractions (p < 0.01). Because the blood flow within the muscle is maintained during the dynamic contraction by enhanced venous return from the contracting muscle, these results suggested that MFVC is affected by the metabolic state in the muscle and the changes in MDF cannot be explained only by that of MFVC.
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J Electromyogr Kinesiol · Apr 1998
ReviewCan muscle models improve FES-assisted walking after spinal cord injury?
Some persons with a spinal cord injury can use functional electrical stimulation (FES) to walk again, but many cannot, and for those that can the walking obtained is limited. This paper argues that muscle models can help improve FES systems, but only if these muscle models are enhanced. Part 1 reviews differences between muscle models for FES systems and those for "natural" movement; FES models emphasize limb angle, demand simplicity, exploit feedback, and grade force through recruitment rather than rate coding. ⋯ Those that do use muscle models provide good control initially, but fare poorly as the muscle properties change. Part 3 lists important questions that muscle models must address: questions of goal, type of activation, spasticity, simulation, simplicity, and fatigue. If these features can be incorporated, models can improve both the design and control of FES systems.
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This paper reviews recent topics of clinical application of functional electrical stimulation (FES) for the paralyzed extremities in Japan. Transcutaneous and percutaneous FES systems have been clinically used in Japan. Candidates of extremity FES arer mostly stroke and spinal cord injury patients. ⋯ Hybrid FES systems using percutaneous and surface electrodes, where FES is used in combination with orthoses, have been applied to the paraplegics because they are highly practical for assisting their locomotive activities. Percutaneous FES have been also provided the amyotropic lateral sclerosis patients with standing up motion. A total implant FES system with 16 output channels is currently developing as a next generation FES system.