Statistical comparison of Jitter and Shimmer voice features for healthy and Parkinson affected persons

Abstract

Parkinson disease (PD) is a neurological diseaseoccurring because of the loss or impairment of the cells that produce dopamine present in the substantia nigra of the brain. This insufficiency affects the movement of the muscles and hence people with Parkinson develop speech impairments related to phonation subsystem which influences the voice features, Jitter and Shimmer. The analysis of these parameters is therefore helpful in diagnosing the disease and also in predicting the severity of the disease. In this paper, statistical analysis of several types of Jitter and Shimmer parameters is carried out on voice samples taken from Parkinson affected and healthy subjects. The various analyses carried out are the descriptive statistics, box plots, correlation analysis, Shapiro-Wilk Test and Mann-Whitney U test. The analysis performed shows a significant difference in the Jitter and Shimmer parameters between the two categories of voice samples.