Q+A CENTER

How important is the health of your voice? For about 7.5 million people in the United States, it's a problem. The National Institute on Deafness and Other Communication Disorders (NIDCD) says that voice disorders involve problems with pitch, loudness and quality.

Here's how it works: Voice is the sound produced using the lungs and the vocal folds (sometimes called cords) in the larynx (voice box). When air from the lungs is pushed past the vocal folds they vibrate. When they don't vibrate normally, problems occur.

There are a great number of research projects. One interesting, imaging-oriented project is being conducted at the University of South Carolina (Columbia, S.C.) where Dr. Dimitar Deliyski of the Arnold School of Public Health, has begun a five-year study to develop a new methodology to help diagnose voice disorders by examining the fine movements of the vocal folds. It's called Laryngeal High-Speed Videoendoscopy (HSV).

"We're looking at the whole scale of voice disorders," he says. "The categories are organic [lesions, cancer, infectious or reflux laryngitis, scarring], neurological [vocal fold paralysis, spasmodic dysphonia] and functional [aphonia, traumatic laryngitis, puberphonia, muscle tension dysphonia]It's a very wide scale of disorders. An initial symptom of a voice disorder is a change in the perceivable quality of the voice. We are looking at what in the vibration of the vocal folds could explain the voice change."

To date, the most common method for imaging the movement of the vocal folds is a method called laryngeal videostroboscopy. Using an endoscope with a standard video camera and a strobe light with special synchronization to flash once during each video frame throughout different phases of the vibration cycle of the vocal folds, videostroboscopy can produce the effects of slow motion when the vibration is periodic.