Jitter and Shimmer Parameters in the Identification of Vocal Tract Pathologies. Current State of Research

Even though parts of a speech signal might seem stationary, there are always small fluctuations in it, as vocal fold oscillation is not exactly periodic. These fluctuations in frequency and amplitude outline two of the most important parameters that characterize the voice signal, namely jitter and shimmer. Both features characterize different aspects concerning particular types of voices and are largely used to describe pathological voices. This paper aims to emphasize the significance of the jitter and shimmer parameters in the identification of the pathologies and disorders that can occur in the vocal tract. The focus of this study is on the previous works developed by different researchers over the world, on the analysis of voiced sounds with the help of jitter and shimmer parameters.