The Effects of a Vocal Loading Task on the Acoustic and Electromyographic Measurements of Vocal Fatigue

Abstract

The purpose of this study was to determine the effect of a vocal loading task on submandibular muscular activity and acoustic measures of vocal function. Surface electromyography (sEMG) directly assessed muscle activation related to extrinsic laryngeal muscles, and these findings were compared to the acoustic measurements of cepstral peak prominence, low to high spectral ratio, semitone range, and amplitude reflecting the function of intrinsic laryngeal muscles. These measurements were taken from 14 healthy, young adults of the Texas Christian University student population before and after reading Harry Potter and the Sorcerer’s Stone for 30 minutes at a volume of at least 75 decibels (dB). Results indicated consistent trends in which acoustic measurement showed more periodic vocal fold movement and reduced vocal range, and sEMG measurement showed reduced muscle activation. An elevated acoustic amplitude suggested that increasing vocal intensity could be a compensatory strategy for individuals with vocal fatigue, but further study is required to test this theory in a larger sample size.

Comments from Mentors

Emily is the embodiment of the student-scholar. Her inquisitive mind led her to develop an innovative research question that is translatable to clinical practice in speech-language pathology and, in fact, will inform that profession through the results of her study. Emily demonstrated the hallmarks of a future scientist, including the intrepidness to ask meaningful questions, the mindfulness to develop a strong experimental methodology, and the organizational skills to both collect data and organize it into a useable set.  The opportunity and experience of mentoring Emily throughout her research project was an enjoyable process for me – it is not often that a faculty member gets the opportunity to work with students who possess the level of talent that Emily Dickson has. I am proud of her accomplishments, and look forward to seeing her realize her future potential as a teacher-scholar who impacts her chosen discipline. 

--Christopher R. Watts