Date of Award


Degree Type


Degree Name

Master of Science (MS)


Communication Sciences and Disorders


Soren Lowell


acoustic measures, aerodynamic measures, CPP, effortful voice, hyperfunction, voice

Subject Categories

Speech Pathology and Audiology


Many voice disorders are associated with an effortful voice; however, there have been very few studies that have examined the physiological changes that contribute to this sense of effort. Determining the factors that contribute to change in vocal effort may help clinicians to effectively target these variables when working with people with voice disorders so that voice improvement is accompanied by decreased vocal effort after treatment. Prior research has shown that alterations in aerodynamic and acoustic variables are often associated with voice disorders involving increased muscular effort, and change in these variables is correlated with abnormal voice qualities. The current study focused on three main questions: 1) When producing speech with increased or decreased vocal effort as compared to comfortable vocal effort, how do healthy adults alter their phonatory physiology? 2) What are the acoustic manifestations of these changes in phonatory function that occur with high vocal effort? 3) Which aerodynamic or acoustic variables are the primary factors that are associated with an increase in vocal effort? The participants included 18 healthy men and women with normal voice and normal hearing, ranging in age from 18 to 26. After training, participants produced repeated syllable combinations at various levels of vocal effort (comfortable, maximal, and minimal). Aerodynamic and acoustic recordings were then analyzed. Three of the four aerodynamic measures in this study showed significant differences between the three vocal effort conditions, and reflected change in airflow, pressure, and rate of airflow change during voice production. Both acoustic measures, which related to the relative degree of harmonic energy in the speech signal also showed significant differences between the three vocal effort conditions.


Open Access