How precisely can the regularity of spontaneous activity be recognized acoustically?

1. Introduction
The electromyographic proof of ongoing denervation and of inflammatory muscle disease relies on the presence of two types of characteristic electrical activity in the completely relaxed muscle. These potentials are termed fibrillation potentials and positive sharp waves (Denny-Brown and Pennybacker, 1938).

However, the activity that indicates disease must be distinguished from activity that occurs physiologically in the region of the neuromuscular junction (endplate potentials and endplate noise, respectively). Also, the muscle might be not completely relaxed and one might record voluntary activity.