Pathological Assesment of Vocal Fold Nodules and Polyp Using Accoustic Perturbation and Phase Space Features

In this study, investigations are carried out from the speech waveform of the patients whose vocal folds vibration pattern has been affected by the presence of nodules and polyp. Acoustic, pitch and amplitude perturbation quotients, and nonlinear dynamic measures, phase space reconstruction and correlation dimension, are scrutinized to analyze a sustained vowel pronounced by these individuals. It is found that the cycle-to-cycle pitch frequency and amplitude variation in the case of polyp is higher than nodules. It is also demonstrated that patients´ voice signals with nodules, in comparison with polyp, has lower-dimensional phase space dynamical characteristics. Classification procedure implemented using support vector machine shows that nonlinear dynamical features provide us with a more prominent description of such benign vocal fold pathologies as a valuable tool for clinical diagnosis applications