World Voice Day 2025: Exploring Laryngeal Motor Control in Hyperfunctional Voice Disorders

April 16th marks World Voice Day, a time to honor the power, nuance, and necessity of the human voice. As a speech-language pathologist who specializes in voice disorders, I witness every day how voice issues can impact a person’s identity, communication, and quality of life.

Voice disorders are more common than many people realize—affecting approximately 10% of the adult U.S. population (Bhattacharyya, 2014). Of those individuals, around 40% experience a hyperfunctional component (Hillman et al., 2020). This condition, often referred to as hyperfunctional voice disorder (HVD) or muscle tension dysphonia, results from excessive strain and tension in the muscles around the larynx during speaking or singing. Symptoms may include hoarseness, vocal fatigue, discomfort, and inconsistent vocal quality.

I work closely with individuals experiencing HVD. Whether it’s a teacher who can’t project in the classroom anymore or a singer who’s lost their range, each voice tells a story—and each one deserves care rooted in both empathy and science.

What’s New in Voice Science?

This year, I’m especially excited to celebrate World Voice Day by highlighting a recent study that advances our understanding of laryngeal motor control in individuals with HVD (Weerathunge et al., 2025. Laryngeal kinematics in vocal hyperfunction. Journal of Speech, Language, and Hearing Research, Volume 68, Number 4)

While the prevalence and clinical characteristics of HVD are well documented, the underlying neuromotor mechanisms remain less understood. This limits our ability to design targeted, evidence-based interventions. Using high-speed videoendoscopy (HSV)—which captures vocal fold motion at ≥1,000 frames per second—researchers were able to observe the biomechanics of the larynx in unprecedented detail.

Why Does This Matter?

Understanding these markers helps clinicians like me move beyond subjective impressions of strain or tightness. For example:

• Kinematic Stiffness (KS) (an estimate of muscle tension during vocal fold movement) gives us insight into whether a person’s vocal folds are overly stiff or resistant to movement, possibly due to chronic misuse or compensatory patterns.

• Spatiotemporal Index (STI) (a measure of vocal production variability) quantifies how consistent (or inconsistent) someone’s voice production is across repetitions—an important clue in diagnosing and tracking HVD.

• Asymmetry Index (AI)  (a marker for motor control asymmetries in vocal fold movement) reflects whether an individual relies more on feedback or pre-programmed movement—a subtlety that may explain why two people with the same trigger (like a respiratory infection) can have very different long-term voice outcomes.

  
  

These findings are exciting because they bring us closer to individualized treatment based on the actual motor control strategies of the larynx, rather than one-size-fits-all voice therapy approaches.

Bringing the Science Into the Therapy Room

In therapy, we often target breath support, vocal hygiene, and efficient voice production—but this research suggests we can go deeper. By better understanding how someone moves their vocal folds and why certain patterns persist, we can tailor strategies that retrain the voice at a neuromuscular level.

For instance, if a client exhibits high KS and STI values, we might use semi-occluded vocal tract exercises (like straw phonation) to reduce tension and build consistency. If their AI is off balance, we may introduce biofeedback techniques to improve feedforward control.

At True Self Speech Therapy, I integrate this evolving research into client care, combining hands-on experience with evidence-based tools. The voice is not just a sound—it’s a behavior, a habit, and, in many ways, a neurobiological dance.

A Voice Worth Celebrating

This World Voice Day, I invite everyone to reflect on the role your voice plays in your life. Do you use it to teach? To sing? To advocate? To connect?

And if your voice isn’t working the way you want it to—know that help is available. Voice therapy can restore function, reduce discomfort, and reconnect you with your true sound.

After all, your voice is part of your identity—and every voice is worth being heard.

📍 Interested in learning more or scheduling a voice evaluation? Visit www.trueselfspeech.com or contact me at 401-415-7525.