AERODYNAMIC AND MYOELASTIC CONTRIBUTIONS TO TRACHEOESOPHAGEAL VOICE PRODUCTION (LARYNGECTOMY, ALARYNGEAL, SPEECH)
Abstract
Some patients with laryngeal cancer require surgical removal of the larynx. Laryngectomized patients often use a surgically reconstructed, upper esophageal sphincter as a substitute voice source during the production of esophageal and tracheoesophageal speech. There is limited published information concerning physiological bases of these two types of alaryngeal voice production. The present project was undertaken to examine aerodynamic and myoelastic contributions to tracheoesophageal voice production on a systematic basis. A specific aim was to test the hypothesis that laryngectomized individuals are incapable of adjusting their voicing source to influence its vibratory rate during voice production. A second aim was to define specific contributions aerodynamic influences make to mediating tracheoesophageal voice. Five laryngectomized, tracheoesophageal speakers served as subjects. They completed two experimental tasks in which they produced vowels (1) at different trans-source airflow rates, and (2) while varying fundamental frequency. The present project was undertaken under the assumption that tracheoesophageal voice production is an aerodynamic event. The results confirm this assumption. Large intersubject differences in average fundamental frequency, trans-source airflow rate, tracheal pressure, and airway resistance were found. Variations in fundamental frequency produced by these tracheoesophageal speakers were always associated with significant positive changes in tracheal pressure. Less consistent relationships were established between fundamental frequency and trans-source airflow rate, and between fundamental frequency and airway resistance. These findings were interpreted to suggest that the single most important aerodynamic mediator of fundamental frequency change in tracheoesophageal voice is driving pressure. A major finding of the present project was that tracheoesophageal speakers were capable of adjusting their voicing source on a systematic basis to influence its vibratory rate during voice production. Taken together, findings were interpreted to suggest that tracheoesophageal voice production should be regarded as a myoelastic-aerodynamic event. Findings were interpreted in relation to existing hypotheses about physiological mechanisms underlying tracheoesophageal voice production and in terms of identifying promising areas of future research.
Degree
Ph.D.
Subject Area
Speech therapy
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