Kay is proud to announce the introduction of the Videokymography (VKG) System, Model 8900, to its family of products. Designed for the direct observation of vocal fold vibratory characteristics, VKG is the ideal complement to stroboscopy.
VKG involves the use of a modified video camera (coupled to a standard rigid endoscope and constant light source) which is capable of capturing high-speed motion such as vocal fold vibration. The VKG camera scans a single line at 8000 lines/second, which is recorded to a standard videocassette recorder for review and analysis.
Developed in the Groningen Voice Research Lab, Dept. of Medical Physiology, University of Groningen, the Netherlands, by Dr. Harm K. Schutte and Dr. Jan Svec (who is now working at the Centre for Communication Disorders, Postgraduate Medical Institute, Prague, the Czech Republic), the videokymographic technique has been used to evaluate hundreds of patients, therein establishing its clinical value. According to Schutte, videokymographic images reflect important properties of vocal fold vibration, including open and closed phases of the glottal cycle, opening and closing movements, displacements of the upper and lower vocal fold margins, and propagation of mucosal waves. As a result, “both researchers as well as clinicians can benefit from the important information regarding vocal fold dynamics gained using this powerful technique.”
The VKG camera offered by Kay functions in either standard, black-and-white composite video mode, or in high-speed mode.
In high-speed mode, a single line from the standard image is selected and scanned at nearly 8000 lines/second. “With each line displayed on the monitor in succession,” explains Schutte, “what you see is a time history representing successive glottal cycles.”
Clinicians can position the endoscope to “select” which portion of the vocal folds (e.g., middle, anterior commissure, etc.) to observe. Additionally, a convenient foot pedal allows the clinician to easily switch between the standard and high-speed modes.
Although the full-screen display of the VKG “image” constituted of single lines is not as intuitive as stroboscopy, VKG does allow direct viewing of vocal fold behaviors which may not be observable with a strobed image.
“For example,” says Schutte, “the high scan rate of the VKG system allows the direct observation of vocal fold motion, even if the motion is aperiodic.” Thus, voicing initiation, diplophonia, biphonia, vocal fry, creaky voice, and aperiodicity, all can be viewed directly. Concludes Schutte, “VKG promises to play a key role in broadening the understanding of phonatory dynamics.”
For more information about the VKG System, contact Kay or your local representative.