Electrical microstimulation with single-fiber electromyography: a useful method to study the physiology of the motor unit.

This article reviews the essential technical principles and findings with electrical microstimulation as used in conjunction with single-fiber electromyography (SFEMG). It highlights the details in the microphysiology of the motor unit that can be conveniently studied with these methods, particularly the neuromuscular transmission at the individual motor endplates, muscle fiber recovery functions, and a variety of late responses. The differences, advantages, and disadvantages of the stimulation method of jitter measurement, compared to the original method, in the voluntarily activated muscle are described. Special attention is given to the pitfalls of the technique. Indications for clinical use of stimulation SFEMG in the electromyography laboratory are suggested.