Control of Paralysed Axial Muscles by Electrical Stimulation

Annu. Rev. Biomed. Eng., 2005

Paralyzed or paretic muscles can be made to contract by applying elec- trical currents to the intact peripheral motor nerves innervating them. When electrically elicited muscle contractions are coordinated in a manner that provides function, the technique is termed functional electrical stimulation (FES). In more than 40 years of FES research, principles for safe stimulation of neuromuscular tissue have been established, and methods for modulating the strength of electrically induced muscle contractions have been discovered. FES systems have been developed for restoring function in the upper extremity, lower extremity, bladder and bowel, and respiratory system. Some of these neuroprostheses have become commercialized products, and others are available in clinical research settings. Technological developments are expected to produce new systems that have no external components, are expandable to multiple applications, are upgradable to new advances, and are controlled by a combination of signals, including biopotential signals from nerve, muscle, and the brain.

Annals of Otology, Rhinology & Laryngology, 1989

A new technique is described that enables discrete activation of individual laryngeal muscles by electrical stimulation across overlying mucosa. In 15 dogs, we defined six distinct motor points by transmucosal stimulation at 3 mA while observing the resulting characteristic position of the arytenoid and true vocal cord. Five dogs were then paralyzed with succinylcholine in order to simulate bilateral vocal cord paralysis. Application of a 3-mA stimulus at each motor point yielded no motion of the cords, but when the current was increased to 20 mA, characteristic responses were elicited. In five other dogs, botulinum toxin was injected directly into laryngeal muscles. Stimulation was used in an attempt to quantify the degree of neuromuscular blockade. In the last group of five dogs, we simulated cricoarytenoid arthritis by scarifying the joint. The extent and nature of the joint's impairment could be demonstrated by stimulation. Transmucosal stimulation appears promising as a cli...

European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery, 2016

The study aim was to identify and analyze intramuscular electrically sensitive points. Electrically sensitive points are herein defined as positions, which allow muscles stimulation with a minimum possible fatigue for a maximum amount of time. A multichannel array electrode was used which could be interesting to retain the function of larynx muscle after paralysis. Eight array electrodes were implanted in the triceps brachii muscle of four rats. While being under anesthesia, the animals were intramuscularly stimulated at 16 different positions. Sihler's staining technique was used to make visible the nerves routes and the intramuscular position of the individual electrode plate. The positions of the motor end plates were determined by means of multichannel-electromyography. The positions that allow longest stimulation periods are located close to the points where the nerves enter the muscle. Stimulation at the position of the motor end plates does not result in stimulation perio...

Biomedical Signal Processing and Control

The present aim was to investigate transcutaneous facial muscle stimulation in order to take further steps in developing facial pacing technology, which can offer a new treatment option for patients with unilateral facial paralysis. This technology ultimately measures muscle activations from one side of the face and simultaneously activates the corresponding muscles of the other side with electrical stimulation. Four facial muscle locations-frontalis, orbicularis oculi, zygomaticus major, and orbicularis oris-of the healthy participants (N = 24) were stimulated to produce an eyebrow raise, eye blink, smile, and lip pucker, respectively. The results showed that a visually observable movement of the forehead and the lower lip was achieved in all participants. On average, the stimulations at the movement threshold were rated as tolerable in terms of pain ratings and neutral in terms of pleasantness ratings. Complete eye blink was achieved in 22 participants, and most did not experience painful sensations. The stimulation of the cheek evoked observable movement in 23 participants, but the stimulation also often resulted in concurrent activation of the eye, mouth, and nose area. The results suggest that transcutaneous stimulation seems to be a promising method for developing further facial pacing technology.

Journal of Visualized Experiments, 2020

Electromyography (EMG) measures the muscle response to electrical stimulation or spontaneous activity of motor units and plays an important role in assessing neuromuscular function. Chronic recording of EMG activity reflecting a muscle's reinnervation status after nerve injury has been limited, due to the invasive nature of traditional EMG recording techniques. In this regard, an implantable system is designed for longterm, in vivo EMG recording and nerve stimulation. It has been applied and tested in a study on reinnervation of laryngeal muscles. This system consists of 1) two bipolar electrode nerve cuffs and leads for stimulating each of two nerves: the recurrent laryngeal nerve (RLN) and internal branch of the superior laryngeal nerve (SLN); 2) two EMG recording electrodes and leads for each of the two laryngeal muscles: posterior cricoarytenoid (PCA) muscle and thyroarytenoid-lateral cricoarytenoid (TA-LCA) muscle complex; and 3) a skin receptacle interfacing all implanted lead terminals to an external recording preamplifier and stimulator using a connection cable. The wire leads are Teflon-coated, multifilament, type 316 stainless steel. They are coiled and can stretch during body movement of the awake animal to prevent lead breakage and electrode migration. This system is implanted during an aseptic surgery. Afterwards, baseline EMG recordings are performed before the RLN is transected in the second surgery to study muscle reinnervation. Throughout the study, multiple physiological sessions are conducted in the anesthetized animal to obtain evoked and spontaneous EMG activity that reflects the reinnervation status of laryngeal muscles. The system is compact, free of infection over the course of the study, and highly durable. This implantable system can provide a reliable platform for research in which long-term recording or nerve stimulation is required in an anesthetized or freely moving animal.

Laryngoscope, 2010

Objectives/Hypothesis: Bilateral stimulation of posterior cricoarytenoid (PCA) muscles offers a physiologic approach to restore ventilation to a normal level in case of bilateral laryngeal paralysis. The objective of this study was to evaluate the long-term efficacy and safety of a new generation stimulator in restoring ventilation and exercise tolerance. Study Design: A prospective study of four canines over 8-20 months. Methods: A Genesis XP stimulator and electrodes were implanted and recurrent laryngeal nerves were sectioned and repaired bilaterally. In bimonthly sessions, vocal fold movement resulted from PCA stimulation or induced hypercapnea, was measured endoscopically in the anesthetized animal. Exercise tolerance was measured on a treadmill and swallowing function was examined endoscopically and radiographically. Results: During the denervation phase, there was minimal ventilatory compromise and near-normal exercise tolerance. PCA stimulation produced only nominal abduction. During the reinnervation phase, synkinetic reinnervation became significant, resulting in a narrowed passive airway and paradoxical glottic closure during hypercapnea. Animals were stridorous and could walk for only 1-2 minutes. Bilateral PCA stimulation increased glottal area, equaling that of a normally innervated animal. Exercise tolerance was also normal. The optimal stimulus paradigm for the synkinetically reinnervated larynx was not different from that for the innervated larynx. Stimulation remained efficacious over the study period. Lead integrity could be maintained by prevention of device migration. There was no evidence of aspiration. Conclusions: This study demonstrates that ventilatory compromise only occurs following faulty reinnervation. Bilateral PCA stimulation can restore ventilation and exercise tolerance completely without aspiration over the long term.

The understanding of these stimulation-induced changes in muscle properties provides a powerful tool for manipulating, in a controlled manner, both normal and diseased muscles. Moreover, stimulation of damaged nerves and tissues seem to increase their potential for repair. Thus the increased knowledge about the effects of electrical stimulation on various parts of our healthy or damaged body allows us to use stimulation as an efficient therapeutic tool. Technical advances in the development of machines that allow efficient and easy methods of stimulation of human muscles and nerves allows us to exploit this knowledge for achieving adaptation of normal muscles to a desired type/shape, and to restore/maintain the properties of muscles that have deteriorated as a result of injury, disease, or other causes. The present book summarizes the effects that long-term electrical stimulation has on muscle and its blood supply, and explains how these modifications can be applied to benefit healthy and sick people. It also provides a guide to be used to decide what type of stimulator is most suitable for particular conditions. Moreover it gives detailed instruction with precise illustrations about the most effective method for stimulating particular muscle groups.

IEEE Transactions on Biomedical Engineering, 1981

An implantable stimulator has been developed for excitation of paralyzed muscle. The stimulator is radio frequency powered and controlled, and has four output channels; there are three sequentially fired and the fourth is independently controlled. The width of each stimulus pulse and the group stimulus frequency are controlied independently by the absence of the 25 MHz powering carrier. The stimulator has been implemented in a thick film hybrid circuit. The circuitry is encapsulated in a ceramic (Macor®), which has hermetically sealed feedthroughs for electrode lead wires.

1986

Recent experimental and clinical work gives strong evidence that functional electrical stimulation (FES) is a powerful tool for regeneration, functional restoration and maintenance of denervated musculature, a fact that for various reasons was not recognized in the past. On reason was the lack of associated technology that in comparison to existing FES equip-ment for nerve stimulation has to meet various completely different demands. Most of the few existing stimulators for denervated muscles provided by industry or published in con-junction with scientific studies are not sufficient for muscle restoration and maintenance due to their limited range of electrical parameters obviously with respect to the presently too restrictive EU regulations for stimulation devices. In order to be effective a stimulator for activation of denervated skeletal muscles via sur-face electrodes requires biphasic long-duration impulses with a pulse width between 10 and 300ms and amplitudes of up to ± 100 ...

Sensors

One of the most common causes for larynx paralysis is the injury of the recurrent laryngeal nerve which, among others, causes the paralysis of the posterior cricoarytenoideus muscle (PCA). Electrical stimulation of PCA offers an approach to retaining the function of the paralyzed larynx muscle. The study aim was to test the applicability of an intramuscular multichannel array electrode as a measuring electrode for myoelectrical potentials and as a possible electrode for stimulation, e.g., posterior cricoarytenoideus muscle stimulation. For this purpose, two different kinds of electrodes were compared. 42 intramuscular multichannel array electrodes and 11 supramysial multichannel electrodes were implanted into the triceps brachii muscle of rats. The triceps brachii muscle of rats is suitable to serve as a substitute muscle for the human PCA muscle in an in vivo animal model. It has the same striated muscle cells, is of comparable size, and fundamentally serves a similar function to t...