Semon's law revisited: an electromyographic analysis of laryngeal synkinesis.

Felix Semon's fascination with vocal fold paralysis led to his theory attributing medialization to isolated abductor paralysis. Later, the Wagner-Grossman hypothesis explained the vocal fold position on the basis of cricothyroid muscle activity. Other authors since that time have dispelled the notion of a role for the cricothyroid muscle in vocal fold position with paralysis. Utilizing laryngeal electromyography, several authors have found electrical activity suggestive of variable reinnervation and synkinesis. This current study included patients with persistent vocal fold immobility. Fourteen patients were studied: half with good voice and half with poor voice. The patients with good voice had a relatively normal arytenoid position and evidence of synkinesis. The group with poor voice had an arytenoid that tipped into the laryngeal inlet and had denervation or poor reinnervation. This suggests that the medialization and upright position of the arytenoid is due to synkinesis.