The variations in the identified features reveal different behavioral origins of voice disorders. The findings open new possibilities for objective documentation and for monitoring vocal fold behavior in clinical practice through kymographic imaging.

Videokymography is advantageous for a more accurate diagnosis of voice disorders. Videokymography provides a simple way to study irregular vibrations of the vocal folds. Information is directly available for further processing and allows a first-time quantification of vibrations registered.

The study presents the first attempt to investigate resonance properties of the living vocal folds by means of laryngoscopy. Laryngeal vibrations were excited via a shaker placed on the neck of a male subject and observed by means of videostroboscopy and videokymography (VKG). When the vocal folds were tuned to the phonation frequency of 110 Hz and sinusoidal vibration with sweeping frequency (in the range 50-400 Hz) was delivered to the larynx, three clearly pronounced resonance peaks at frequencies around 110, 170, and 240 Hz were identified in the vocal fold tissues. Different modes of vibration of the vocal folds, observed as distinct lateral-medial oscillations with one, two, and three half-wavelengths along the glottal length, respectively, were associated with these resonance frequencies. At the external excitation frequencies below 100 Hz, vibrations of the ventricular folds, aryepiglottic folds and arytenoid cartilages were dominant in the larynx.

Log Phon Vocol 1997; 22: 152-156Stroboscopy is based on the assumption that the vibration is stable and regular. Irregular vibrations, as is often the case in voice pathology, cannot easily be studied by stroboscopy. Videokymography overcomes this drawback. Videokymography, using a modified CCD video camera, makes it possible to observe all kinds of regular and irregular vocal fold vibrations, including those leading to pathological voice productions, It easily visualises small left-right asymmetries, open and closed phases of the selected part of the glottis, lateral propagation of mucosal waves, movements of the upper margin and, in the closing phase, the lower margin of the vocal folds. This is advantageous for a more accurate diagnosis of voice disorders. Also other fields which study mechanical vibrations, like strings of musical instruments, may benefit from videokymography.

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