Application of nonlinear methods for analyzing rate of speech production

Abstract

This pilot study has examined the rate of repetitive speech production through use of nonlinear methods. Durational measures were obtained from a normal subject who was required to produce a stimulus word in four speaking conditions: normal, controlled-normal, accelerated, and controlled-accelerated. Phase plots and accumulated time series plots were utilized to display intra-subject variability. Attractors were observed in each of the four phase plots and of particular interest was the direction of their shift for the different speaking conditions. The accumulated time series plots also revealed patterns of intra-subject variability across time. In summary, these two forms of nonlinear representation successfully characterized qualitative changes within, and across, the four speaking conditions. The observed spectral distributions and patterns of variability have implications for differentiating normal from abnormal speaking conditions.