The effects of acute stress on perceived and objective extralaryngeal muscle tension in vocally healthy subjects

Maria Dietrich, Katherine Verdolini

Elevated stress reactivity and personality factors such as introversion coupled with neuroticism continue to be cited as factors in the development or maintenance of Muscle Tension Dysphonia (MTD) (Dietrich & Verdolini, in press; Roy & Bless, 2000). Unfortunately, much necessary psychobiological stress research is sparse around the relationships among stress-emotion-voice. In our research, we aim to explore the objective and subjective effects of acute stress on the subjects’ extralaryngeal muscle tension (surface electromyography) and perceived vocal effort as well as concurrent levels of emotional/cognitive (state emotion, rumination) and physiological stress reactivity (blood pressure, heart rate) as a function of personality.
We will present data on 18 vocally healthy females (regular and otolaryngological control group and individuals high in both introversion and neuroticism) who each participated in two sessions of a social-evaluative stress reactivity protocol that included a baseline rest, stress (public speaking and non-speech mental arithmetic one week apart), and recovery phase as well as baseline speech and recovery speech recordings. Preliminary results indicate that subjects highest on the traits introversion and (social) anxiety reacted with more negative emotions and rumination throughout the protocol than subjects who did not exhibit these characteristics. Cardiovascular reactivity was generally correlated with the degree of negative affect experienced. Further, increased perceived vocal effort during stress was only experienced in selected subjects who were highest on introversion, social anxiety, and state negative affect during the stress task. Surface EMG findings will complement the results.
In conclusion, stress is an intertwined psychological, emotional, cognitive, physiological, and behavioral cascade of events that may influence vocal perceptions and behaviors. Importantly, individuals may be differentially vulnerable for laryngeal muscle tension based on their pattern of stress reactivity and the person by situation interaction. Similar future data for patients with MTD will further enlighten the specific pathways that regulate relations between stress and voice in a theoretically-guided context.

Maria Dietrich, Diplom-Heilpädagogin, M.A., CCC-SLP¹
Katherine Verdolini, Ph.D., CCC-SLP^1,2

¹Communication Science and Disorders
University of Pittsburgh
²University of Pittsburgh Voice Center
4033 Forbes Tower
Pittsburgh, Pennsylvania 15260, USA
Phone: +1 (412) 383-6709 Fax: +1 (412) 383-6555
E-mail: mmd17@pitt.edu, kittie@csd.pitt.edu