title: Nonlinear dynamic analysis of voices before and after surgical excision of vocal polyps.
abstract: Phase space reconstruction, correlation dimension, and second-order entropy, methods from nonlinear dynamics, are used to analyze sustained vowels generated by patients before and after surgical excision of vocal polyps. Two conventional acoustic perturbation parameters, jitter and shimmer, are also employed to analyze voices before and after surgery. Presurgical and postsurgical analyses of jitter, shimmer, correlation dimension, and second-order entropy are statistically compared. Correlation dimension and second-order entropy show a statistically significant decrease after surgery, indicating reduced complexity and higher predictability of postsurgical voice dynamics. There is not a significant postsurgical difference in shimmer, although jitter shows a significant postsurgical decrease. The results suggest that jitter and shimmer should be applied to analyze disordered voices with caution; however, nonlinear dynamic methods may be useful for analyzing abnormal vocal function and quantitatively evaluating the effects of surgical excision of vocal polyps.
authors.affiliation: Department of Surgery, Division of Otolaryngology Head and Neck Surgery, University of Wisconsin Medical School, Madison, Wisconsin 53792-7375, USA. zhang@surgery.wisc.edu
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Clancy
authors.initials: C
authors.lastname: McGilligan
authors.forename: Liang
authors.initials: L
authors.lastname: Zhou
authors.forename: Mark
authors.initials: M
authors.lastname: Vig
authors.forename: Jack J
authors.initials: JJ
authors.lastname: Jiang
mesh_terms: D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007818:Laryngeal Diseases / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D017711:Nonlinear Dynamics; D011127:Polyps / Q000503:physiopathology / Q000601:surgery*; D013068:Speech Production Measurement; D016896:Treatment Outcome; D014833:Voice Quality