Summary: Stress can influence voice disorders. Researchers observed that higher salivary cortisol levels corresponded with brain activity affecting the laryngeal region. Participants with lower extraversion were more likely to show stress-linked speech reactions.

Source: University of Missouri

Stress, Brain Activity, and Voice Disorders: What the Research Shows

Glossophobia—the fear of public speaking—is one of the most common anxieties and can disrupt voice control, causing stammering or the sensation commonly described as a “frog in the throat.” New research from the University of Missouri indicates that beyond simple nervousness, stress triggers specific brain activations that can affect vocal control and contribute to voice disorders.

Maria Dietrich, associate professor of speech, language and hearing sciences in the MU School of Health Professions, investigates the neurological and behavioral mechanisms behind voice disorders. In a pilot study, Dietrich extended the Trait Theory of Voice Disorders—often applied to functional voice problems—and found evidence that stress-induced brain responses can lead to conditions such as muscle tension dysphonia. This disorder arises from excessive or altered muscle tension in and around the voice box, changing the voice’s sound and the speaker’s sensation.

“For many, public speaking can be a stressful situation,” Dietrich said.

“Stress can trigger physiological changes such as increased muscle tension, which in turn can alter speech. Our findings clarify how stress and vocal control interact at the brain level and help pinpoint which neural activations may contribute to disordered voice, guiding better targeted treatments.”

Study Design and Measures

The study recruited vocally healthy young women who were pre-screened to participate. To induce stress, participants were told they would prepare a five-minute impromptu speech explaining why they were the best candidate for a job. While the speech preparation served as a social-evaluative stressor, participants were only asked to read sentences and were never required to deliver the speech.

Researchers monitored stress responses by collecting saliva samples at intervals before the stressor and up to about 50 minutes afterward to measure cortisol, the body’s primary stress hormone. Participants also completed a personality questionnaire and rating scales to assess emotional state. Functional MRI scans captured brain activations during voiced and whispered sentence productions both with and without the speech-preparation stressor.

Key Findings

The study identified clear differences in how stress altered brain activity related to speech. Across participants, exposure to the public-speaking anticipation stressor produced peak activation in the right caudate and simultaneous deactivations in several regions, including parts of the anterior cingulate cortex, inferior frontal gyrus, insula, putamen, and thalamus. Importantly, individual differences emerged: higher cortisol responses correlated with lower activity in the laryngeal motor cortex and with lower extraversion scores.

These results suggest that stress modifies phonatory control by shifting limbic-motor interactions in the brain. In practical terms, individuals who are more introverted or who mount stronger cortisol responses to social-evaluative situations may be more prone to stress-related disruptions in vocal motor control—potentially increasing the risk for disorders like primary muscle tension dysphonia.

“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 said.

Practical Tips for Managing Public-Speaking Stress

• Don’t assume a lack of visible reaction from the audience means negative judgment—listeners may simply be focused or neutral.
• Adopt an inner smile and practice steady breathing; deep breaths help calm the body and reduce muscle tension.
• Accept that feeling nervous is normal—acknowledging anxiety often makes it easier to manage.

Publication and Funding

The study, titled “Limbic and cortical control of phonation for speech in response to a public speech preparation stressor,” appears in Brain Imaging and Behavior. The research was supported by the National Center for Research Resources, the National Center for Advancing Translational Sciences (UL1TR001998), and the Center for Clinical and Translational Science Pilot Research Program. University of Kentucky researchers Richard Andreatta, Yang Jiang, and Joseph Stemple also contributed to the work. The authors note that the content is solely their responsibility and does not necessarily represent the official views of the funding agencies.

Original Research (open access): Maria Dietrich, Richard D. Andreatta, Yang Jiang, Joseph C. Stemple. Brain Imaging and Behavior. doi: 10.1007/s11682-019-00102-x

Source:
University of Missouri
Media Contacts:
Sheena Rice – University of Missouri
Image Source:
The image is in the public domain.