Vocalization Subsystem Responses to a Temporarily Induced Unilateral Vocal Fold Paralysis Purpose The purpose of this study is to quantify the interactions of the 3 vocalization subsystems of respiration, phonation, and resonance before, during, and after a perturbation to the larynx (temporarily induced unilateral vocal fold paralysis) in 10 vocally healthy participants. Using dynamic systems theory as a guide, we hypothesized ... Research Article
Research Article  |   March 15, 2018
Vocalization Subsystem Responses to a Temporarily Induced Unilateral Vocal Fold Paralysis
 
Author Affiliations & Notes
  • Daniel J. Croake
    University of Kentucky, Lexington
  • Richard D. Andreatta
    University of Kentucky, Lexington
  • Joseph C. Stemple
    University of Kentucky, Lexington
  • Disclosure: The authors have declared that no competing interests existed at the time of publication.
    Disclosure: The authors have declared that no competing interests existed at the time of publication. ×
  • Correspondence to Daniel J Croake: djcroa2@uky.edu
  • Editor-in-Chief: Julie Liss
    Editor-in-Chief: Julie Liss×
  • Editor: Jack Jiang
    Editor: Jack Jiang×
Article Information
Speech, Voice & Prosodic Disorders / Voice Disorders / Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   March 15, 2018
Vocalization Subsystem Responses to a Temporarily Induced Unilateral Vocal Fold Paralysis
Journal of Speech, Language, and Hearing Research, March 2018, Vol. 61, 479-495. doi:10.1044/2017_JSLHR-S-17-0227
History: Received June 13, 2017 , Revised October 23, 2017 , Accepted October 27, 2017
 
Journal of Speech, Language, and Hearing Research, March 2018, Vol. 61, 479-495. doi:10.1044/2017_JSLHR-S-17-0227
History: Received June 13, 2017; Revised October 23, 2017; Accepted October 27, 2017

Purpose The purpose of this study is to quantify the interactions of the 3 vocalization subsystems of respiration, phonation, and resonance before, during, and after a perturbation to the larynx (temporarily induced unilateral vocal fold paralysis) in 10 vocally healthy participants. Using dynamic systems theory as a guide, we hypothesized that data groupings would emerge revealing context-dependent patterns in the relationships of variables representing the 3 vocalization subsystems. We also hypothesized that group data would mask important individual variability important to understanding the relationships among the vocalization subsystems.

Method A perturbation paradigm was used to obtain respiratory kinematic, aerodynamic, and acoustic formant measures from 10 healthy participants (8 women, 2 men) with normal voices. Group and individual data were analyzed to provide a multilevel analysis of the data. A 3-dimensional state space model was constructed to demonstrate the interactive relationships among the 3 subsystems before, during, and after perturbation.

Results During perturbation, group data revealed that lung volume initiations and terminations were lower, with longer respiratory excursions; airflow rates increased while subglottic pressures were maintained. Acoustic formant measures indicated that the spacing between the upper formants decreased (F3–F5), whereas the spacing between F1 and F2 increased. State space modeling revealed the changing directionality and interactions among the 3 subsystems.

Conclusions Group data alone masked important variability necessary to understand the unique relationships among the 3 subsystems. Multilevel analysis permitted a richer understanding of the individual differences in phonatory regulation and permitted subgroup analysis. Dynamic systems theory may be a useful heuristic to model the interactive relationships among vocalization subsystems.

Supplemental Material https://doi.org/10.23641/asha.5913532

Acknowledgments
This research was supported by a seed grant from the University of Kentucky Center for Clinical and Translational Science, awarded to the first author. The authors would like to acknowledge Logan Spears for his assistance with data collection, Sanford Archer for his supervision of participants during the study, and Jessica Huber for contributing her time for training the first author in the acquisition and analysis of the respiratory kinematic measures.
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