Effectiveness of Recurrence Quantification Measures in Discriminating Subjects With and Without Voice Disorders

The objective of this study was to analyze the accuracy of recurrence quantification measurements (RQMs) in discriminating between individuals with and without voice disorders. This study consisted of a total of 541 recorded voice samples from normal and dysphonic subjects. All subjects recorded a sustained vowel /Ɛ/ and underwent a laryngoscopic examination of the larynx. Twelve RQMs and three parameters related to the topology of the phonatory system were extracted from the samples, for a total of 15 measures. The classification used quadratic discriminant analysis and includes the measures of accuracy, sensitivity, and specificity. Single measurements such as Shannon's entropy, average diagonal length, and transitivity had only acceptable performance ratings (≥70%) in discriminating between individuals with and without voice disorders. The combination of the parameters average diagonal length, Shannon's entropy, trapping time, length of the longest vertical line, tau, imbedding dimension, neighborhood radius, and transitivity produced the highest accuracy in discrimination (83.27%). Therefore, the performance of RQMs related to the formation of diagonal lines in classifying individuals with and without voice disorders was acceptable at ≥70%. A combination of RQMs showed good performance in discriminating between the study groups, with higher sensitivity and specificity.