Effects of Straw Phonation Through Tubes of Varied Lengths on Sustained Vowels in Normal-Voiced Participants.

OBJECTIVE: To examine the immediate effects of straw phonation exercises in normal subjects while altering the effective length of the vocal tract.

STUDY DESIGN: A nonrandomized comparison of semi-occluded vocal tract length during straw phonation exercises was carried out.

METHODS: Oral pressure, mean airflow, aerodynamic resistance, and contact quotient were measured in 20 healthy subjects immediately before and after straw phonation exercises. A short- and long-duration phonatory task was used to examine the voice parameters during semi-occluded vocal tract exercises. These tasks involved repeating a vocalization of the vowel /a/ through a tube. Each subject underwent the protocol using tubes of three different lengths (7.5 cm, 15 cm, and 30 cm) to allow for the effect of moving the outlet of the vocal tract distal to the mouth to be monitored.

RESULTS: Oral pressure and aerodynamic resistance decreased significantly, contact quotient showed a decreasing trend, and airflow increased significantly in pre- and postmeasurements 15 minutes after a long-duration phonatory task. Short-duration tasks were found to have no effect on voice parameters.

CONCLUSION: The results present and validate a method to isolate the effect that the length of a semi-occluded vocal tract has during straw phonation exercises.