Vocal jitter at different fundamental frequencies: A cardiovascular-neuromuscular explanation

Abstract

<h2>Summary</h2> As a widely used descriptor of phonatory behavior, vocal fundamental frequency perturbation (jitter) has received much attention in the recent voice literature. Despite this, the exact causes of this cycle-to-cycle frequency variability are only poorly understood. Associated with attempts to characterize this vocal parameter and to standardize its measurement, many investigators have alluded to a relationship between jitter magnitude and the fundamental frequency of phonation without mention of the underlying physiology. This article reviews two jitter-inducing mechanisms (one based on normal cardiovascular function and the other on normal neuromuscular function) and describes how they help to explain the observed nonlinear dependence of short-term frequency variability on the frequency of phonation in the normal voice.