A case against teflon injection to lower vocal pitch. A patient with severe hoarseness was seen three months after Teflon injection of both vocal folds had been performed elsewhere to lower an abnormally high pitch. Pitch analysis utilizing voice spectrography revealed no significant drop in fundamental frequency. The hoarseness is presumed to have resulted from disparate glycerin absorption, inflammatory changes of the folds, and asynchronous vibration of the folds. Vocal fold injection to increase fold thickness and lower pitch is not a simple technique and is not advised until all parameters have been thoroughly studied. Published in The Journal of speech and hearing disorders (1975)

An in-house 3D fluid–structure–acoustic interaction numerical solver was employed to investigate the effect of subglottic stenosis (SGS) on dynamics of glottal flow, vocal fold vibration and acoustics during voice production. The investigation focused on two SGS properties, including severity defined as the percentage of area reduction and location. The results show that SGS affects voice production only when its severity is beyond a threshold, which is at 75% for the glottal flow rate and acoustics, and at 90% for the vocal fold vibrations. Beyond the threshold, the flow rate, vocal fold vibration amplitude and vocal efficiency decrease rapidly with SGS severity, while the skewness quotient, vibration frequency, signal-to-noise ratio and vocal intensity decrease slightly, and the open quotient increases slightly. Changing the location of SGS shows no effect on the dynamics. Further analysis reveals that the effect of SGS on the dynamics is primarily due to its effect on the flow resistance in the entire airway, which is found to be related to the area ratio of glottis to SGS. Below the SGS severity of 75%, which corresponds to an area ratio of glottis to SGS of 0.1, changing the SGS severity only causes very small changes in the area ratio; therefore, its effect on the flow resistance and dynamics is very small. Beyond the SGS severity of 75%, increasing the SGS severity, leads to rapid increases of the area ratio, resulting in rapid changes in the flow resistance and dynami

Using a three-dimensional continuum model of phonation, this study investigates the effects of changes in subglottal pressure, vocal fold approximation and stiffening, and vocal fold medial surface thickness on vocal fold vibration and acoustics. The results show that increasing subglottal pressure leads to more or less uniform increase in harmonic energy across a very large frequency range as well as significant increase in noise production. Reduced noise production can be achieved by increasing medial surface thickness, vocal fold approximation, or vocal fold stiffening. Increasing vocal fold thickness and stiffness also lead to increased production of high-frequency harmonics. The closed quotient of vocal fold vibration depends primarily on the medial surface thickness of the vocal fold, with the closed quotient increasing with increasing thickness. The closed quotient also slightly decreases with increasing subglottal pressure, but increases with increasing vocal fold approximation and stiffening. These results suggest that, in addition to increasing subglottal pressure, vocal loudness can be also increased by increasing vocal fold thickness, approximation and/or stiffening to increase production of higher-order harmonics and reduce noise production, which leads to a perceived increase in vocal intensity. [Work supported by NIH.]

The collision threshold pressure (CTP), i.e. the smallest amount of subglottal pressure needed for vocal fold collision, has been explored as a possible complement or alternative to the now commonly used phonation threshold pressure (PTP), i.e. the smallest amount of subglottal pressure needed to initiate and sustain vocal fold oscillation. In addition, the effects of vocal warm-up (Paper 1) and vocal loading (Paper 2) on the CTP and the PTP have been investigated. Results confirm previous findings that PTP increases with an increase in fundamental frequency (F0) of phonation and this is true

the fluid-filled vocal cords. The swelling of the vocal folds causes the voice to become deep and hoarse. Therefore, the major symptom of Reinke's edema Reinke's edema is the swelling of the vocal cords due to fluid (Edema) collected within the Reinke's space. First identified by the German anatomist Friedrich B. Reinke in 1895, the Reinke's space is a gelatinous layer of the vocal cord located underneath the outer cells of the vocal cord. When a person speaks, the Reinke's space vibrates to allow for sound to be produced (phonation). The Reinke' Squamous epithelium Superficial lamina propria (Reinke's space) Intermediate lamina propria Deep lamina propria Vocalis muscle In order for humans to produce sound for speech, the vocal folds must readily vibrate. The two layers of the vocal cords that vibrate are the Reinke's space and the overlying epithelium. In fact, these layers move freely over the more rigid intermediate and deep lamina proprias. Accumulation of fluid within the Reinke's space alters the elasticity of the vocal cord, making it less stiff and more gelatinous. This slows the vocal cord vibration, which results in a deepened and hoarse voice. Because men normally have a lower voice than women, the change is more noticeable in women. Edema usually occurs on both vocal cords. This is known as bilateral Reinke's edema. The pathophysiology or mechanism of Reinke's edema is not well known, however, chemicals contained within cigarette smoke are associated with an increased vascular permeability of blood vessels, which results in fluid leaking into the Reinke's space. Normally, the vocal cords are surrounded by neatly aligned blood vessels, however, these blood vessels can become disarranged and fragile in Reinke's edema. In addition, cigarette smoke can create reactive oxygen species that alter the environment of the vocal cords. Tissue analysis of Reinke's edema shows decreased amounts of the proteins fibronectin, elastin, collagens I and III, and… Grade I – Lesions contact the anterior third of the vocal fold Grade II – Lesions contact the anterior two-thirds of the vocal fold Grade III – Lesions contact the entirety of the vocal fold If further evaluation is needed, stroboscopy is used to examine the mucosal waves of the vocal cords. Mucosal waves describe the waves produced by vibration of the vocal cords during speech. Stroboscopes produce flashes of light that are timed to the patient's vocal frequency. Every time the light is flashed, it will create a still frame image of the vocal cords at that particular moment in time. These are combined to produce an image of the wave. In the case of Reinke's edema, structural changes to the vocal cords will result in abnormal wave patterns.

this note; and the numerical value of the pitch is the number of vibrations per second or the frequency of the note. See ACOUSTICS. Pitch , a black resinous