Chapter

Single-Fiber Electromyography and Related Studies

Jay A. Liveson and Dong M. Ma

in Laboratory Reference for Clinical Neurophysiology

Published in print May 1999 | ISBN: 9780195129243
Published online March 2012 | e-ISBN: 9780199847792 | DOI: http://dx.doi.org/10.1093/acprof:oso/9780195129243.003.0019
Single-Fiber Electromyography and Related Studies

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The techniques described in this chapter depend on the ability of the examiner to isolate single-fiber action potentials (SFAPs). These are the electrical potentials caused by the discharge of single muscle fibers. By careful manipulation of this needle during minimal contraction, the examiner can isolate an individual SFAP and use it as the basis for studies. Other specialized equipment is necessary. A trigger device must be available that permits the sweep to be triggered by an SFAP. A delay line is necessary. Furthermore, the oscilloscope must be capable of fast sweep speeds and variable filter settings. In single-fiber electromyography (SFEMG), the object is to study the relationship between two fibers of the same motor unit. During an examination, most of the SFAPs appear as isolated potentials. These potential pairs are the ones that can be studied. One of these serves as the trigger potential and the other as the slave potential.

Keywords: single-fiber action potentials; trigger device; oscilloscope; single-fiber electromyography; trigger potential; slave potential; single muscle fibers

Chapter.  2389 words.  Illustrated.

Subjects: Neuroscience

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