Acoustic Myography as a Noninvasive Technique for Assessing Muscle Function: Historical Aspects and Possibilities for Application in Clinical Practice

Abstract

Acoustic myography is a technique for detecting and measuring mechanical oscillations of a sound/infrasound-range frequency produced during muscle contractions; such oscillations can be recorded using special microphones. We described the history of formation of the so-called acoustic myography (AMG) and modern concepts on recording the respective phenomena. Fundamental features of these biological signals, possible advantages and disadvantages of AMG, technical approaches used, and problems arising in application of this technique are discussed. Some own results obtained using an AMG technique for assessment of the function of the lower esophageal sphincter (LES) are described. Analysis of the spectrum of the respective oscillations showed that it contained mostly low-frequency components (from a few Hz up to 15–20 Hz) corresponding to contractions of smooth muscles when the LES is in a closed state. Acoustic myography may occupy a noticeable position among noninvasive techniques of recording of muscle activity; its application in clinics is quite possible. Further studies are needed to substantiate the possibilities of AMG applications and to estimate positive and negative aspects of this technique and its reliability.