Dynamics of the Driving Force During the Normal Vocal Fold Vibration Cycle

Abstract

Intraglottal pressure is the driving force of vocal fold vibration. Theoretically, simultaneous quantification of glottal area and transglottal airflow allows calculating the intraglottal pressure waveform during a single vibration cycle. In this study, we show that, by combining photoglottography (transglottal light transmission) and airflow (Rothenberg’s mask) measurements during sustained vocal emissions in vivo, the intraglottal pressure wave can be approximated in a way similar to what has been done in models. The results confirm in vivo that the intraglottal pressure is systematically larger during the opening phase than during the closing phase, so that over one whole cycle, the driving force performs net positive work, accounting for sustained vocal fold motion. A component of this driving force asymmetry is related to vocal tract inertance, which also accounts for the skewing of the airflow waveform compared to the area waveform. Furthermore, the intraglottal pressure ratio (opening/closing) increases with voicing intensity, reaches a maximum around 76 dB, and significantly decreases at higher intensities. This rise and fall suggests that there is a range of intensity values in which, mechanically, a maximum of the driving force is imparted to the vocal fold mass. This finding could have implications for voice economy in professional speakers.

Development of three‐dimensional laryngostroboscopy for office‐based laryngeal diagnostics and phonosurgical therapy

“…In the 2D view from above, the vocal folds move medially toward each other, giving the impression of a complete closure of the glottis . Because they are on a different level, they allow too much air to pass through the glottis, causing alterations of the normal vocal fold vibration cycle and dysphonia . In this case, the evaluation of the closing and closure process, as well as the determination of symmetry between the left and right vocal fold, would be important.…”

“…38 Because they are on a different level, they allow too much air to pass through the glottis, causing alterations of the normal vocal fold vibration cycle and dysphonia. 39,40 In this case, the evaluation of the closing and closure process, as well as the determination of symmetry between the left and right vocal fold, would be important. As assumed, the newly invented 3D imaging system can visualize such information.…”

The Physics of the Human Vocal Folds as a Biological Oscillator

“…at the beginning or end of the utterance, can be validly compared. Depending on the type of search, light signals can be expressed as a percentage of the maximum signal value, between 0 and 100% [2]. The Physics of the Human Vocal Folds as a Biological Oscillator DOI: http://dx.doi.org/10.5772/intechopen.113958…”

“…The intraglottic pressure P can be calculated from the transglottic flow rate and the air particle velocity (= flow/surface) based on Bernoulli's law of energy [2,11,29]:…”

“…The human voice results from the vibration of air at the vocal folds (VF), which behave as a damped oscillator driven by two forces: the transglottic airflow and the intraglottic pressure [1,2].…”