Stress may cause vocal disorders

By Angela Betsaida B. Laguipo, BSNJul 25 2019

Do you feel anxious about talking in front of the crowd and feel as if there’s a frog in your throat? New reseach says that stress may be the culprit for such vocal issues.

In a new study by researchers at the University of Missouri in Columbia, they wanted to determine the connection between stress and voice disorders, particularly muscle tension dysphonia.

Glossophobia or the phobia or fear of speaking in public can affect voice control, which causes stammering, or a feeling as if there’s a “frog in the throat”. In the study published in the journal of Brain Imaging and Behavior, the researchers found that vocal problems can be caused by a multitude of factors than just nervousness, as it may be triggered by stress-induced brain activations.

Orotracheal intubation procedure. Image Credit: Lorena Huerta / Shutterstock

The Trait Theory of Voice Disorders

The co-author of the study, Maria Dietrich, associate professor of speech, language, and hearing sciences, is an expert in voice disorders. The Trait Theory of Voice Disorders, which was formulated by Roy and Bless in 2000 has been suggested to describe the potential clinical relevance of the limbic system and its role in voice production.

Dietrich expanded on this theory and found that brain activations triggered by stress may contribute to the development of voice disorders, including muscle tension dysphonia.

Muscle tension dysphonia (MTD) is a change in the feel or sound of the voice due to excessive muscle tension around the larynx or voice box. Usually, patients with MTD may experience hoarseness and other symptoms related to voice production. The exact cause of MTD is still unclear, but many risk factors have been identified, including acid reflux, allergies, illness, irritants, and increased vocal demand. In some cases, underlying stress or anxiety is to be blamed.

“For many, public speaking can be a stressful situation. We know that stress can trigger physiological changes such as muscle tension and that can impact our speech,” Dietrich explained.

“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,” she added.

Stress-induced brain activations related to speech

To arrive at the study findings, the researchers recruited 13 vocally healthy women who were pre-screened to partake in the study. They were asked to prepare for a five-minute impromptu speech, but they were never asked to give the speech. The impromptu speech was intended to be a stressor for the participants.

Instead, they underwent event-related sparse-sampling fMRI protocol, which included a voiced and whispered sentence production by asking them to read sentences, with or without exposure to a stressor.

Aside from that, the researchers collected saliva samples for cortisol measurement, which is a major stress hormone in the body. The saliva samples were taken before the stressor has been given and 50 minutes after. They also completed a personality questionnaire and rating scales of a negative emotional state.

Also, the researchers took MRI scans of the patients throughout the experiment to determine and visualize brain activations and how they affected speech, for those with a stressor and those without stressors.

The researchers found differences in stress-induced brain activations associated with speech. The participants who showed increased cortisol levels in their saliva showed brain activity that affected the area in the brain controlling the larynx or voice box. They also incurred lower scores on 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,” the researchers concluded in the study.

The researchers also said the findings of the study shows that the theories of vocal traits are related to personality.

“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.

She then emphasized on many recommendations for those who have a fear of public speaking, and how to deal with the situation. Don’t worry about the audience if they’re not smiling, this doesn’t mean they are judging you.

She also encouraged public speakers to take a deep breathe to shake off all of the nervousness and stress. Lastly, she said that feeling nervous is normal and don’t let it take the best of you.