Objective Methods of Sample Selection in Acoustic Analysis of Voice

Abstract

Objectives:

In acoustic voice analysis, the fact that reproducible methods of sample selection have not been defined impedes research study generalizability and clinical assessment of treatment efficacy. Because perturbation results differ along a single signal, this study sought to establish objective methods of sample selection by use of a moving window to determine the most stable regions of phonation.

Methods:

Voice signals obtained from 21 patients affected by laryngeal conditions associated with Parkinson's disease were analyzed to study jitter, shimmer, signal-to-noise ratio, and correlation dimension parameters when various sample selection procedures were used. Objectively selected voice samples were chosen based upon 5%, 10%, and 20% variance from a signal's minimum perturbation value. The stability of these samples, defined by the standard deviations of the acoustic measurements, was compared to the stability of unselected samples and subjectively selected samples.

Results:

A significant decrease in standard deviation values of acoustic parameters was found in comparing the objectively selected samples (particularly those selected with 5% and 10% variance) to the subjectively selected and unselected samples.

Conclusions:

These results suggest that the development of an objective sample selection method may have significant effects on the stability and reliability of acoustic voice measurements.