Seeing Speech: High-speed video imaging for improved voice health

Newswise — When we talk, the delicate tissues of the voice box vibrate faster than the eye can see to convey a complex range of meaning. But researchers and physicians are finally able to visualize and investigate this physiological feat, thanks to the development of a high-speed imaging system by a research team at the Center for Laryngeal Surgery and Voice Rehabilitation at the Massachusetts General Hospital. The team’s goal is to improve vocal health by understanding the movements of the vocal folds.

Using the same high-speed video technology that enables nature photographers to visualize the rapid beating of hummingbird wings, the Boston team has begun to observe and document details of vocal vibrations and voice acoustics that have never before been appreciated during clinical evaluations. Team members include Daryush D. Mehta, Ph.D.; Matías Zañartu, Ph.D.; Thomas F. Quatieri, Sc.D.; Dimitar D. Deliyski, Ph.D. and Robert E. Hillman, Ph.D. They will present their work at the annual meeting of the Acoustical Society of America in San Diego, Calif.

Explains research team member Mehta, “For the first time, voice scientists are able to investigate detailed relationships between vocal vibrations and sound qualities of the human voice. For example, we are just now discovering that certain asymmetric vibration patterns do not necessarily degrade one's voice acoustics as once thought.” This level of detail is possible due to recent technological advances in high-speed imaging of the larynx, including enhanced light sensitivity of digital camera sensors. It enables researchers to capture and analyze high-resolution video – exceeding 10,000 images per second – of vocal fold oscillations that occur too fast (100-1,000 times per second) for the eye to perceive. The video system the team developed for clinical research tracks multiple variables. These include synchronous acquisition of acoustic data, as well as electrodes to relay information about when the vocal folds make contact. Acceleration of the neck skin near the larynx is also measured as an indicator of vocal function. This is because research shows that acceleration of this area arises from vocal fold vibrations and the airflow pulses the vibrations create. The airflow and pressure within the mouth are also measured.

With this comprehensive monitoring system to analyze air flow and vibration patterns, the research team hopes to improve clinical care of patients who have damaged or impaired voices. By helping pinpoint the deficits in vocal fold vibration, the high-speed video monitoring system can help identify anatomical areas that would optimally benefit from surgery or therapeutic treatment.

This team’s work grew out of an urgent need to assess the true vibratory characteristics of vocal fold bio-implants that are currently under development at the Massachusetts General Hospital Voice Center.

The paper 3aSCa1, “Use of laryngeal high-speed videoendoscopy systems to study voice production mechanisms in human subjects,” will be presented Wednesday morning, Nov. 2.