Neuromuscular stimulation

The related /V-oxide (77) demonstrates pharmaceutical activity without structural modification, being used as a radiosensitizer to promote tumour regression during radiation therapy (B-80MI20904). Similarly, 4-acetamidopyridine 1-oxide (78) has been described as a neuromuscular stimulant (80MI20905). A carboxylic acid derivative (79) demonstrating anticancer activity independent of any radiation treatment has recently been reported (81JMC1181). 

A. Classification Muscarinic agonists are parasympathomimetic, ie, they mimic the actions of parasympathetic nerve stimulation. Five subgroups of muscarinic receptors have been identified (Table 7-3), but selective agonists for these receptor subtypes are not available for clinical use. Nicotinic agonists are classified on the basis of whether ganglionic or neuromuscular stimulation predominates however, agonist selectivity is very limited. On the other hand, relatively selective antagonists are available for the two nicotinic receptor types (Chapter 8). 

A biomedical control system that utilizes a neurophysiologically-based approach has been developed for use in Functional Neuromuscular Stimulation (FNS) systems [Abbas, 1995 Abbas and Chizeck, 1995). FNS is a rehabilitation engineering technique that uses computer-controlled electrical stimuli to activate paralyzed muscle. The task of a control system is to determine appropriate stimulation levels to generate a given movement or posture. The neural network control system utilizes a block diagram structure that is based on hierarchical models of the locomotor control system. It also utilizes a heterogenous network of neurons, some of which are capable of endogenous oscillation. This network has been shown to provide rapid adaptation of the control system parameters [Abbas and Chizeck, 1995 Abbas and Triolo, 1997] and has been shown to exhibit modulation of reflex responses [Abbas, 1995]. 

Abbas, J.J. and Chizeck, H.J. 1995. Neural network control of functional neuromuscular stimulation... 

Abbas, J.J. and Triolo, R.J. 1997. Experimental evaluation of an adaptive feedforward controller for use in functional neuromuscular stimulation systems. IEEE Trans. Rehabil. Eng., 5 12—22. 

Yamaguchi, G.T. and Zajac, F.E., Restoring unassisted natural gait to paraplegics via functional neuromuscular stimulation a computer simulation study, IEEE Trans. Biomed. Eng. BME-37 886-902,1990. 

Liberson, W.T., Functional neuromuscular stimulation historical background and personal experience, in Functional Neuromuscular Stimulation Report of a Workshop. April 27-28, 1972, M.A. LeBlanc, Ed. 1972, Washington, DC, pp. 147-156. 

Cooper, E.B., W.H. Bunch, and J.H. Campa, Effects of chronic human neuromuscular stimulation. Surg. Forum., 1973. 24 477-479. 

Graupe, D. and Kohn, K.H. (1998), Functional neuromuscular stimulator for short-distance ambulation by certain thoracic-level spinal-cord-injured paraplegics, Surg. Neurol., 36 202-207. 

Chaplin, E. (1995), Functional neuromuscular stimulation for mobility in people with spinal cord injuries. The Parastep I system, /. Spinal Cord Med., 19 99-105. 

The holy grail of all these efforts is the restoration of movement to the paralyzed. For example, quadriplegics need to use their hands, and cortical control of functional neuromuscular stimulation devices would appear to be the answer to this need. These systems, though they will provide access to cortical control signals, may not alone restore movement to those with spinal cord injury instead, I suspect these recording technologies will be hybridized with spinal cord regeneration efforts to restore movement to... 

Here we present technical aspects of the available externally powered orthoses and prostheses that interface directly or indirectly with the human neuro-musculo-skeletal system. We elaborate here two methods for the restoration of movements in humans with paralysis functional activation of paralyzed muscles termed functional electrical stimulation (FES) or functional neuromuscular stimulation (FNS or NMS), and parallel application of FES and a mechanical orthosis called hybrid assistive system (HAS). We also describe externally controlled and powered leg and arm/hand prostheses. 

Neural Prosthesis — Assistive systems for replacing or augmenting sensory-rootor fimcion Functional electrical stimulation or Functional neuromuscular stimulation Patterned electrical stimulation of neuromuscular structures dedicated to restore motor functions. 

Sennels, S., Biering-Soerensen, E, Anderson, O.T., and Hansen, S.D., Functional neuromuscular stimulation control by surface electromyographic signals produced by volitional activation of the same muscle adaptive removal of the muscle response from the recorded EMG-signal, IEEE Trans. Rehab. Eng. TRE-5 195 206,1997. 

Grill, J.H. and Peckham, P.H., Functional neuromuscular stimulation for combined control of elbow extension and hand grasp in C5 and C6 quadriplegics, IEEE Trans. Rehab. Eng. TRE-6 190-199,1998. 

Ziaie, B., Nardin, M.D., Coghlan, A.R., and Najafi, K., A single channel implantable microstimulator for functional neuromuscular stimulation, IEEE Trans. Biomed. Eng. BME-44 909-920, 1997. 

Functional Electrical Stimulation Technology for Delivering Stimulation Pulses to Excitable Tissue Stimulation Parameters Implantable Neuromuscular Stimulators Packaging of Implantable Electronics Leads and Electrodes Safety Issues of Implantable Stimulators Implantable Stimulators in Clinical Use Future oflmplantable Electrical Stimulators Summary Defining Terms References Further Information... 

The term implantable stimulation refers to stimulation systems in which all three components, pulse generator, lead wires, and electrodes, are permanently surgically implanted into the body and the skin is solidly closed after the implantation procedure. Any interaction between the implantable part and the outside world is performed using telemetry principles in a contact-less fashion. This chapter is focused on implantable neuromuscular stimulators, which will be discussed in more detail. 

FIGURE 16.2 Block diagram of an implantable neuromuscular stimulator. 

The internal electronic structure of an implantable neuromuscular stimulator is shown in Figure 16.2. It consists of receiving and data retrieval circuits, power supply, data processing circuits, and output stages. 

Implantable stimulators for neuromuscular control are an important tool in rehabilitation of paralyzed individuals with preserved neuromuscular apparatus, as well as in the treatment of some neurological disorders that result in involuntary motor activity. Their impact on rehabilitation is still in its infancy however, it is expected to increase with further progress in microelectronics technology, development of smaller and better sensors, and with improvements of advanced materials. Advancements in neurophysiological science are also expected to bring forward wider utilization of possibilities offered by implantable neuromuscular stimulators. 

Triolo, R.J., Bieri, C., Uhlir, J., Kobetic, R., Scheiner, A., and Marsolais, E.B. 1996. Implanted functional neuromuscular stimulation systems for individuals with cervical spinal cord injuries Clinical case reports. Arch. Phys. Med. Rehabil. 77 1119. 

Improper use of electrosurgery may expose both the patient and the surgical staff to various hazards. By far, the most frequent hazard is an undesired burn. Less frequent are undesired neuromuscular stimulation, interference with pacemakers, or other devices, fires, and gas explosions [1,3]. 

Peckham, P.H. et al.. Functional neuromuscular stimulation system. United States Patent 5,167,229. www.uspto.gov/patfv/index.html, 1992. 

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