If a motor nerve is stimulated from an external electrode, the resulting action potential will propagate to the innervated muscle and a twitch will be produced. The muscle responds to the artificially initiated nerve signal just as it would a naturally occurring signal. For patients with (for example) spinal cord injury, signals originating in the brain may be unable to reach the desired motoneuron because of a transected cord. In this case, the affected muscle is paralyzed although it may, otherwise, be healthy and capable of excitation and contraction. In this situation an artificial signal initiated in the nerve will evoke a response. Devising strategies for the stimulation of motoneurons (or the muscle itself) to effect desired muscle contraction is the goal of functional neuromuscular stimulation (FNS), and the subject of this chapter.
KeywordsTransmembrane Potential Functional Electrical Stimulation Nerve Trunk Virtual Cathode American Physiological Society
Unable to display preview. Download preview PDF.
- 1.T. Mortimer, Motor prostheses, Handbook of Physiology, Section I: The Nervous System, Volume II, Motor Control, Part I, American Physiological Society. Bethesda, MD, 1981, pp. 155–187.Google Scholar
- 2.A. J. Bard and L. R. Faulkner, Electrochemical Methods: Fundamentals and Applications. Wiley, New York, 1980.Google Scholar
- 4.L. S. Robblee and T. L. Rose, Electrochemical guidelines for selection of protocols and ele ctrode materials for neural stimulation, in Neural Prostheses, W. F. Agnew and D. B. McCreery, eds., Prentice-Hall, Englewood Cliffs, NJ, 1990.Google Scholar
- 5.K. Henneberg and R. Plonsey, Boundary element analysis in bioelectricity, in Industrial Applications of the Boundary Element Method, C. A. Brebbia and M. H. Aliabadi, eds., Computational Mechanics Publications, Southampton, 1993.Google Scholar
- 7.W. F. Agnew and D. B. McCreery, eds., Neural Prostheses, Prentice-Hall Englewood Cliffs, NJ, 1990, Chaps, 6, 9, 11.Google Scholar
- 8.B. Frankenhaeuser and A. Huxley. The action potential in the myelinated nerve fiber of Xenopus Laevis as computed on the basis of voltage clamp data, J. Physiol 171:302–315 (1964).Google Scholar
- 9.J. H. Reilly, Electrical models for neural excitation studies, APL Digest 9:44–58 (1988).Google Scholar
- 11.G. Lundborg, Nerve Injury and Repair, Churchill-Livingston, London, 1988.Google Scholar
- 12.G. Naples, J. T. Mortimer, and T. G. Yuen, Overview of peripheral nerve electrode design and implantation, in Neural Prostheses, W. F. Agnew and D. B. McCreery, eds., Prentice-Hall, Englewood, Cliffs, NJ, 1990.Google Scholar
- 15.M. Karkar, Nerve excitation with a cuff electrode—a model, M.S. Thesis, Case Western Reserve University, Cleveland, Ohio, 1975.Google Scholar
- 16.W. B. Marks, Polarization changes of stimulated cortical neurons caused by electrical stimulation at the cortical surface, in Functional Electrical Stimulation, J. B. Reswick and F. T. Hambrecht, eds., Academic Press, New York, 1977.Google Scholar
- 18.S. W. Kuffler and E. M. Vaughn Williams, Small nerve functional potentials. The distribution of small motor nerves to frog skeletal muscle, and the membrane characteristics of the fibers they innervate, J. Physiol. 121:289–317 (1953).Google Scholar