Characterization of cough sounds using statistical analysis

TL;DR

This study analyzes cough sounds using spectral and statistical features to distinguish them from speech, providing insights into their characteristics for potential respiratory disease diagnosis.

Contribution

It introduces a statistical analysis approach of spectral features for characterizing cough sounds with and without voiced content, comparing them to speech.

Findings

Spectral features like roll-off, centroid, and bandwidth are higher in cough sounds than in speech.

Spectral flatness in cough sounds reaches 0.22, indicating distinct spectral properties.

Zero Crossing Rate of cough sounds mostly between 0.05 and 0.4.

Abstract

Cough is a primary symptom of most respiratory diseases, and changes in cough characteristics provide valuable information for diagnosing respiratory diseases. The characterization of cough sounds still lacks concrete evidence, which makes it difficult to accurately distinguish between different types of coughs and other sounds. The objective of this research work is to characterize cough sounds with voiced content and cough sounds without voiced content. Further, the cough sound characteristics are compared with the characteristics of speech. The proposed method to achieve this goal utilized spectral roll-off, spectral entropy, spectral flatness, spectral flux, zero crossing rate, spectral centroid, and spectral bandwidth attributes which describe the cough sounds related to the respiratory system, glottal information, and voice model. These attributes are then subjected to statistical analysis using the measures of minimum, maximum, mean, median, and standard deviation. The experimental results show that the mean and frequency distribution of spectral roll-off, spectral centroid, and spectral bandwidth are found to be higher for cough sounds than for speech signals. Spectral flatness levels in cough sounds will rise to 0.22, whereas spectral flux varies between 0.3 and 0.6. The Zero Crossing Rate (ZCR) of most frames of cough sounds is between 0.05 and 0.4. These attributes contribute significant information while characterizing cough sounds.