The use of acoustic myography to assess changes in muscle control with ageing in healthy subjects ranging 20 to 79 years.

This study has used acoustic myography as a technique to assess not only the number of active fibres and their firing frequency, but also the efficiency with which they are recruited, to re-examine age-related changes in movement. It is known that ageing results in less precise and controlled muscle movements, changes that also occur with some neurological diseases. The aim of this study was therefore to look at the control with which two muscles, an extensor and a flexor, are activated and determine how, as well as which, changes occur with increasing age. In the upper limb it appears that the flexor declines later than the extensor muscle (m.Biceps vs. m.Triceps). This study lends support to the published evidence that proprioception and postural stability are regulated to some extent by muscle spindles and that this process is age-related. The changes are identifiable in the acoustic myography parameters (E-score and ST-score) and are observed in a muscle-specific manner.