An Acoustic and Electroglottographic Study of the Aging Voice With and Without an Open Jaw Posture.

Objectives: This study aimed to determine if the use of an "open jaw" posture in healthy aging adults would result in voice improvement detectable through acoustic and electroglottographic measurements.

Study Design: A convenience sampling strategy was used to recruit 85 participants, with at least five females and five males in each of four age groups, between age 35 and 50 years (35+), above 50 (50+), 60+, and 70+ years.

Methods: Participants sustained the vowel /a/ at three pitch levels (normal, low, and high) and repeated the test sentence "We saw two cars" in both a normal and an open jaw postures. A selection of acoustic and electroglottographic measures were derived from the steady midportion of the vowel segments extracted from the sustained and embedded vowels to identify measures sensitive to the effects of jaw posture, age group, gender, and pitch.

Results: Results from a four-way (two jaw postures × four age groups × two genders × three pitch levels) Mixed Model Multivariate Analysis of Variance showed a significant four-way interaction effect. For both genders, an open jaw posture led to an increase of fundamental frequency (F0), formant one frequency, and vowel space area and a decrease of the amplitude difference of the first two harmonics and %Jitter. With an open jaw posture, speed quotient decreased for females and open quotient increased for females but decreased for males.

Conclusions: An open jaw posture was generally associated with positive changes in vocal behaviors, including higher F0, improved phonatory stability, and voice clarity.