Application of functional electrical stimulation to the paralyzed extremities

Self-Powered Direct Muscle Stimulation Using a Triboelectric Nanogenerator (TENG) Integrated with a Flexible Multiple-Channel Intramuscular Electrode

Muscle function loss can result from multiple nervous system diseases including spinal cord injury (SCI), stroke, and multiple sclerosis (MS). Electrical muscle stimulation is clinically employed for rehabilitative and therapeutic purpose and typically requires mA-level stimulation current. Here, we report electrical muscle stimulation, which is directly powered by a stacked-layer triboelectric nanogenerator (TENG) through a flexible multiple-channel intramuscular electrode. This multiple-channel intramuscular electrode allows mapping of motoneurons that is sparsely distributed in the muscle tissue and thus enables high efficiency TENG muscle stimulation, although the short-circuit current of the TENG is only 35 μA. With a stimulation efficiency matrix, we find the electrical muscle stimulation efficiency is affected by two factors, namely, the electrode-motoneuron position, and the stimulation waveform polarity. To test whether it is a universal phenomenon for electrical stimulation, we then further investigate with the conventional square wave current stimulation and confirm that the stimulation efficiency is also affected by these two factors. Thus, we develop a self-powered direct muscle stimulation system with a TENG as power source and waveform generator, and a multiple-channel intramuscular electrode to allow motoneuron mapping for stimulation efficiency optimization. We believe such self-powered system could be potentially used for rehabilitative and therapeutic purpose to treat muscle function loss.

An overview and categorization of dynamic arm supports for people with decreased arm function

BACKGROUND

Assistive devices that augment arm function were already introduced during the polio era. Devices are still being developed, but a review has not been performed thus far.

OBJECTIVE

To create an overview and categorize assistive devices facilitating arm function in activities of daily living for people with decreased arm function.

STUDY DESIGN

Literature review.

METHODS

A systematic review in three scientific literature databases. Conference proceedings, assistive technology databases, and references were searched and experts consulted. This resulted in a database of dynamic arm supports. Product information was added, and the devices were categorized.

RESULTS

A total of 104 dynamic arm supports were found. These could be categorized as nonactuated devices (N = 39), passively actuated devices (N = 24), actively actuated devices (N = 34), or devices using the functional electrical stimulation principle (N = 7). Functionality analysis resulted in second-level categorization: tremor suppression, facilitation of anti-gravity movement, and assistance of specific joint motion.

CONCLUSION

All devices could be ordered in a categorization of low complexity. Many have been developed; most have disappeared and have been succeeded by similar devices. Limitations of the devices found mainly concern interfacing and the range of motion facilitated. Future devices could make use of whatever residual strength is available in the users' arm for control.

CLINICAL RELEVANCE

The provided overview of devices in this article and the classification developed is relevant for practitioners seeking assistive solutions for their clients as it makes the range of developed solutions both accessible and comprehensible.

Transcutaneous neuromuscular electrical stimulation (VitalStim) curative therapy for severe dysphagia: myth or reality?

OBJECTIVES

VitalStim therapy was approved by the US Food and Drug Administration in 2001 for the treatment of dysphagia through the application of neuromuscular electrical stimulation to cervical swallowing muscles. This approval was based upon submission of data on more than 800 patients who received this therapy collected by the principal developer and patent-holder of the device. The therapy is marketed as successful in restoring long-term swallowing function in 97.5% of dysphagic patients past the point of requiring a feeding tube and as significantly better than existing therapies. More than 2,500 speech-language pathologists have taken the certification course, and thousands of devices have been sold. To date, however, aside from the developer's own studies, there are no peer-reviewed publications supporting these claims. We sought to evaluate the effectiveness of VitalStim therapy in a heterogeneous group of dysphagic patients.

METHODS

We performed a retrospective analysis of 18 patients who received this therapy at an urban tertiary referral center. All patients underwent pretherapy evaluation by speech-language pathologists, including modified barium swallow and/or functional endoscopic evaluation of swallowing and clinical evaluation of swallowing that included assessment of laryngeal elevation, diet tolerance, and swallowing delay, and were then assigned an overall dysphagia severity score. After therapy, all patients underwent the same assessments. Twelve of the 18 also underwent a functional swallowing telephone survey months (range, 1 to 21 months) after their therapy to assess whether the improvement was worthwhile and sustained.

RESULTS

Eleven of the 18 patients (61%) demonstrated some improvement in their swallowing. Six of the 18 patients (33%) were improved enough to no longer require a feeding tube. However, of the 5 patients categorized as having "severe dysphagia" before therapy, only 2 showed any improvement, and these patients still required a feeding tube for adequate nutrition. Telephone surveys did confirm that those who improved with their therapy seemed to maintain their progress and that most patients were satisfied with their therapy.

CONCLUSIONS

VitalStim therapy seems to help those with mild to moderate dysphagia. However, the patients with the most severe dysphagia in our study did not gain independence from their feeding tubes. The authors conclude that VitalStim therapy clearly has a place in the management of dysphagia, but that the most severely afflicted are unlikely to gain dramatic improvement.