Summary: Stress can have an impact on voice disorders. Researchers found those with higher salivary cortisol levels also exhibited brain activity that impacted the larynx. Those who were more introverted were more likely to have stress reactions related to speech.
Source: University of Missouri
Glossophobia, or the fear of public speaking, often comes up in lists of greatest fears. Such anxiety can often impact voice control leading to stammering or feeling like there is a “frog in your throat.” A researcher from the University of Missouri has found that there is more to vocal issues than just feeling nervous and that stress-induced brain activations might be to blame.
Maria Dietrich, associate professor of speech, language and hearing sciences in the MU School of Health Professions, studies voice disorders. In a pilot study, Dietrich expanded on the Trait Theory of Voice Disorders, often used in understanding functional voice disorders. She discovered that stress-induced brain activations could lead to voice disorders such as muscle tension dysphonia, a disorder from excessive or altered muscle tension in and around the voice box changing the sound or feel of one’s voice.
“For many, public speaking can be a stressful situation,” Dietrich said.
“We know that stress can trigger physiological changes such as muscle tension and that can impact our speech. The new findings will help researchers better understand the relationship between stress and vocal control and will allow us to pinpoint the brain activations that impact voices to identify better treatments for disorders.”
For the study, young women who were pre-screened to participate were told that they had to prepare for a five-minute impromptu speech about why they were the best candidate for a job. The speech preparation test served as a stressor while participants were asked to read sentences but were never prompted to give their speech. Researchers collected samples of saliva to test for cortisol, the body’s main stress hormone, in intervals before the stressor until approximately 50 minutes after.
During the study, participants were asked a series of questions to assess their emotional state. Throughout the experiment, MRI scans were taken of the participants for the researchers to see brain activations and how they impacted speech with and without stressful speech preparation.
Dietrich found that there were differences in stress-induced brain activations related to speech. Participants who exhibited higher cortisol responses also exhibited brain activity that impacted the larynx region in the brain and had lower scores on aspects of extraversion.
“Our findings are consistent with theories of vocal traits related to personality,” Dietrich said. “Those who are more introverted are more likely to have stress reactions related to speaking and their brains are registering that stress, which could impact their vocal control.”
Dietrich offers the following advice for those who feel stressed about public speaking:
Don’t worry about the audience not smiling. Just because people might not be reacting to your public address, it doesn’t mean they are judging you.
Present with an inner smile and remember to breathe. Taking a deep breath can go a long way to calm nerves.
Acknowledge that feeling nervous is normal.
“Limbic and cortical control of phonation for speech in response to a public speech preparation stressor,” recently was published in Brain Imaging and Behavior.
Funding: The study was supported by the National Center for Research Resources and the National Center for Advancing Translational Sciences (UL1TR001998), and the Center for Clinical and Translational Science Pilot Research Program. The study also received support from the University of Kentucky researchers Richard Andreatta, Yang Jiang and Joseph Stemple who contributed to the study. The content is solely the responsibility of the authors and does not necessarily represent the official views of the funding agencies.
About this neuroscience research article
Source: University of Missouri Media Contacts: Sheena Rice – University of Missouri Image Source: The image is in the public domain.
Limbic and cortical control of phonation for speech in response to a public speech preparation stressor
Knowledge on brain networks subserving vocalization in vocally healthy individuals under various task conditions is scarce but paramount to understand voice disorders. The aims of our study were to determine (1) the effect of social-evaluative stress on the central neural control of phonation underlying speech production; and (2) the neural signature, personality profile, and aerodynamic vocal function in relation to salivary cortisol responses. Thirteen vocally healthy females underwent an event-related sparse-sampling fMRI protocol consisting of voiced and whispered sentence productions with and without exposure to the social-evaluative stressor public speaking anticipation. Participants completed a personality questionnaire, rating scales of negative emotional state, and provided salivary cortisol samples. In the total sample, the task contrast of voiced productions revealed that stressor exposure resulted in a peak activation in the right caudate with concomitant deactivations in the bilateral pgACC and aMCC, and right IFG, BA 9, BA 10, insula, putamen, and thalamus. There were individual differences in stressor-induced brain activations as a function of stress reactivity with greater cortisol reactivity linked with lower laryngeal motor cortex activity and lower scores on aspects of extraversion. Our data confirm that stress alters the phonatory control for speech production through limbic-motor interactions. The findings support the Trait Theory of Voice Disorders (Roy and Bless 2000) and help provide critical insights to the study of voice disorders such as primary muscle tension dysphonia.