Selectivity and sensitivity of intramuscular and transcutaneous electromyography electrodes

Neuromuscular Electrical Stimulation for Motor Restoration in Hemiparesis

This article assesses the clinical efficacy of established neuromuscular electrical stimulation (NMES) technologies for motor restoration in hemiparesis and provides an overview of evolving technologies. Transcutaneous NMES facilitates motor recovery. However, its impact on physical disability remains uncertain. Transcutaneous NMES also decreases shoulder subluxation, but its effect on shoulder pain remains uncertain. Clinically deployable upper extremity neuroprosthesis systems will not be available until sometime in the distant future. However, there is stronger evidence for the clinical utility of lower extremity neuroprosthesis systems. Evolving technology utilizes semi-implanted or fully implanted systems with more sophisticated control paradigms. Initial experiences with these systems are reviewed and directions for future research are discussed in this article.

The Influence of Modeling Separate Neuromuscular Compartments on the Force and Moment Generating Capacities of Muscles of the Feline Hindlimb

Functional electrical stimulation (FES) has the capacity to regenerate motion for individuals with spinal cord injuries. However, it is not straightforward to determine the stimulation parameters to generate a coordinated movement. Musculoskeletal models can provide a noninvasive simulation environment to estimate muscle force and activation timing sequences for a variety of tasks. Therefore, the purpose of this study was to develop a musculoskeletal model of the feline hindlimb for simulations to determine stimulation parameters for intrafascicular multielectrode stimulation (a method of FES). Additionally, we aimed to explore the differences in modeling neuromuscular compartments compared with representing these muscles as a single line of action. When comparing the modeled neuromuscular compartments of biceps femoris, sartorius, and semimembranosus to representations of these muscles as a single line of action, we observed that modeling the neuromuscular compartments of these three muscles generated different force and moment generating capacities when compared with single muscle representations. Differences as large as 4 N m (∼400% in biceps femoris) were computed between the summed moments of the neuromuscular compartments and the single muscle representations. Therefore, modeling neuromuscular compartments may be necessary to represent physiologically reasonable force and moment generating capacities of the feline hindlimb.

Intramuscular Electrical Stimulation for Upper Limb Recovery in Chronic Hemiparesis: An Exploratory Randomized Clinical Trial

Background. Surface electrical stimulation (ES) has been shown to improve the motor impairment of stroke survivors. However, surface ES can be painful and motor activation can be inconsistent from session to session. Percutaneous intramuscular ES may be an effective alternative. Objective. Evaluate the effectiveness of percutaneous intramuscular ES in facilitating the recovery of the hemiparetic upper limb of chronic stroke survivors. Methods. A total of 26 chronic stroke survivors were randomly assigned to percutaneous intramuscular ES for hand opening (n = 13) or percutaneous ES for sensory stimulation only (n = 13). The intramuscular ES group received cyclic, electromyography (EMG)-triggered or EMG-controlled ES depending on baseline motor status. All participants received 1 hour of stimulation per day for 6 weeks. After completion of ES, participants received 18 hours of task-specific functional training. The primary outcome measure was the Fugl-Meyer Motor Assessment. Secondary measures included the Arm Motor Ability Test and delay and termination of EMG activity. Outcomes were assessed in a blinded manner at baseline, at the end of ES, at the end of functional training, and at 1, 3, and 6 months follow-up. Results. Repeated measure analysis of variance did not yield any significant treatment, or time by treatment interaction effects for any of the outcome measures. Conclusion. Percutaneous intramuscular ES does not appear to be any more effective than sensory ES in enhancing the recovery of the hemiparetic upper limb among chronic stroke survivors. However, because of the exploratory nature of the study and its inherent limitations, conclusions must be drawn with caution.

Neuromuscular electrical stimulation for motor relearning in hemiparesis

Neuromuscular electrical stimulation may have an important role in improving the motor function of stroke survivors. Active, repetitive movement training mediated by transcutaneous cyclic and EMG-triggered NMES may facilitate the motor recovery of stroke survivors. Multicenter, double-blinded, randomized clinical trials should be pursued to confirm the motor-relearning effects of transcutaneous NMES and to define appropriate prescriptive specifications. Intramuscular EMG-controlled NMES may be superior to transcutaneous systems and is presently undergoing preliminary randomized clinical trials. Neuroprostheses systems may provided the highest level of goal-oriented activity and cognitive investments, which may lead to significant motor relearning. Implementation of clinically viable neuroprosthesis systems, however, will probably require additional technical developments including more reliable control paradigms and methods for blocking undesirable muscle contractions. In view of the dynamic nature of the present health care environment, the future of NMES technology is difficult to predict. By necessity, scientists and clinicians must continue to explore new ideas and to improve on the present systems. Components will be smaller, more durable, and more reliable. Control issues will remain critical for both motor relearning and neuroprosthetic applications, and the implementation of cortical control is likely to dictate the nature of future generations of NMES systems. Finally, consumers will direct future developments. In the present health care environment, where cost has become an overwhelming factor in the development and implementation of new technology, the consumer will become one of technology's greatest advocates. The usual drive toward greater complexity will be tempered by the practical issues of clinical implementation, where patient acceptance is often a function of a tenuous balance between the burden or cost associated with using a system and the system's impact on the user's life.

Intramuscular electromyographically controlled neuromuscular electrical stimulation for upper limb recovery in chronic hemiplegia

We report three cases of survivors of chronic stroke who were treated with active repetitive movement training of the paretic finger extensors mediated by intramuscular electromyographically controlled neuromuscular electrical stimulation for the purpose of motor relearning. These case reports demonstrate the feasibility of using intramuscular electromyographically controlled neuromuscular electrical stimulation for facilitating the upper limb motor recovery of chronic stroke survivors with mild to moderate hemiplegia.

Intramuscular electromyographically controlled neuromuscular electrical stimulation for ankle dorsiflexion recovery in chronic hemiplegia

We report three cases of survivors of chronic stroke treated with active repetitive movement training of the paretic ankle dorsiflexors mediated by intramuscular electromyographically controlled neuromuscular electrical stimulation (NMES). These case reports demonstrate the feasibility of using intramuscular electromyographically controlled NMES for facilitating ankle dorsiflexion recovery among survivors chronic stroke with moderate hemiplegia. Relevant issues for clinical implementation and future investigations are reviewed.