Resonance properties of the vocal folds: in vivo laryngoscopic investigation of the externally excited laryngeal vibrations.

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.

First results of clinical application of videokymography.

OBJECTIVES: Stroboscopy is based on the assumption that the vibration of the vocal folds is stable and regular. Irregular vibrations, which are common in voice pathology, cannot easily be studied and described in a reliable way. Videokymography overcomes most of these drawbacks. DESIGN: The use of the recently invented videokymography for studying vocal fold vibrations in patients is introduced. METHOD: Videokymography, using a modified CCD-video camera, works in two modes: standard and high speed. In standard mode the vocal folds are displayed on a video monitor in the usual way, providing 50 images per second (or 60 in the National Television Standards Committee (NTSC) system). This is used for routine laryngoscopic and stroboscopic examination of the larynx. In high-speed mode (nearly 8000 images per second) only one line from the whole image is selected and displayed on the x-axis of the monitor; the y-axis represents the time dimension. RESULTS: All kinds of vocal fold vibrations, including those leading to pathological rough, breathy, hoarse, or diplophonic voice productions can be observed. Videokymography visualizes small left-right asymmetries, open quotient differences along the glottis, lateral propagation of mucosal waves, and movements of the upper margin and, sometimes in the closing phase, the lower margin of the vocal folds. CONCLUSION: 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.

Three-dimensional phonetographic assessment of voice performance in professional and non-professional speakers.

For the assessment of voice performance, three-dimensional (3D) phonetograms were constructed using mean values of vocal pitch, vocal intensity, and phonation time. They were built up for groups of professional and non-professional male and female speakers. The 3D phonetograms of the professional and non-professional groups were projected into one another for the female as well as for the male speakers to facilitate comparison of the professional and non-professional groups. In addition, pitch-related cross-sections of the 3D phonetograms were created. These cross-sections plotted as sequences are useful to evaluate changes in vocal dynamics and phonation time in relation to the course of vocal pitch. In this contribution, it could be demonstrated that the 3D phonetograms of the non-professional groups were completely enclosed by those of the professional groups who developed a greater vocal capacity. Furthermore, the cross-section sequences of the professional groups were obviously longer and broader than those of the non-professional groups. Details of group-specific differences with respect to the examined voice parameters are discussed.

[Dilation of stenoses of the oral part of the esophagus in the Kelly-Paterson syndrome (Plummer-Vinson)]. / Dilatace zúzení orální cásti jícnu u syndromu Kelly-Paterson (Plummer-Vinson).

The dilatation of oesophagus oral portion in the Kelly-Paterson (Plummer Vinson) syndrome was made in two female patients at the age of 58 and 81 years. For the extreme stenosis (2 and 3 mm) of the lumen the dilatation was first performed by the Grüntzig Catheter and after extension above 5 mm special oesophageal catheters with a balloon of 15 mm diameter (Cook) were used. The dilatation proved successful in both patients. The dilatation in the K.-P. syndrome must be performed with care beginning with catheters of small diameter and narrow end with a step-wise slow filling of the balloon. A good anesthesia of upper respiratory pathways and swallowing passages is required.

Firing pattern of motor units in the vocal muscle during phonation.

Electromyographic activity of the vocal muscle was analysed in 10 subjects during the phonation of different vowels and with different voice pitches. Analysis of the firing pattern of single or a few motor units was performed with the aid of an amplitude discriminator on the computer. The firing rate increases with increasing voice pitch (in the region co-ho the decrease of mean interspike interval with the slope 30-40 msec/octave was found). In the firing pattern of several motor units the periodicity was observed to be correlated with the voice pitch. The period of 8 msec corresponding H, 123 Hz, decreased to about 6 msec during phonation of do, 147 Hz. The periodicity was present both in units with pure prephonatory activity and in units which were active during phonation. It seems possible that the activity in the vocal muscle changes characteristically during the phonation of different vowels.