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Respiratory system
Published in A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha, Clark’s Procedures in Diagnostic Imaging: A System-Based Approach, 2020
A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha
In normal circumstances air passes from the lungs through the vocal folds stimulating a vibration, which produces sound (Fig. 4.1). This sound is then shaped by the tongue, teeth, lips and hard and soft palates to produce speech. However, following laryngectomy, voice restoration is typically achieved through surgical voice restoration (SVR). SVR enables the patient to pass expired air from the lungs through a voice prosthesis placed between the trachea and oesophagus. This air then passes into the reconstructed pharynx to the vibratory segment (also known as the pharyngo-oesophageal segment) to stimulate sound. As in voice produced with a larynx, this sound is then shaped into speech by the tongue, teeth, lips and hard and soft palates (Fig. 4.2a). However, some patients experience difficulty with producing a laryngeal voice. In order to establish any anatomical or physiological reasons for this, a videofluoroscopic swallow is performed. This is sometimes combined with an ‘air insufflation test’, which facilitates the passage of air into the reconstructed pharynx via a catheter passed through the nose. Air insufflation assesses the tonicity of the vibratory segment. Difficulty producing alaryngeal phonation may be due to hypotonicity of the vibratory segment or hypertonicity, spasm and stricture [1].
G
Published in Carl W. Hall, Laws and Models, 2018
GEOMETRODYNAMIC LAW A combined law of geometry and dynamics which states that forces on all space have this foam-like character, that is, permeated everywhere with wormholes. Keywords: foam-like, forces, dynamics, geometry, space Source: Taylor, J. G. 1975. GERBER LAW An empirical law (Fig. G.1) regarding fatigue of materials whereby the alternating stress for a given endurance plotted on the ordinate and the mean static tensile strength plotted on the abscissa, gives the shape of a parabola: SA = S[1 – (SM/ut)2] where SA = alternating stress SM = tensile strength ut = ultimate tensile strength Keywords: alternating stress, fatigue, strength, tensile GERBER, John Gottfried Heinrich, 1832-1912, German engineer Source: Thewlis, J. 1961-1964. See also GOODMAN GERHARDT LAW; GERHARDT-SEMON LAW; SEMON-ROSENBACH LAW In a progressive destructive lesion of the motor nerve supplying the largyneal muscles, the abductor mechanism is affected before that of adduction. Various peripheral and central lesions affecting the recurrent largyneal nerve cause the vocal cord to move to an intermediate position between where the muscle draws away from the main axis (abduction) and where the muscle draws toward the main axis (adduction), and the paralysis of the parts is incomplete. Keywords: laryngeal, lesions, nerve, throat, vocal GERHARDT, Adolf Christian Jacob, 1833-1902, German physician SEMON, Sir Felix, 1849-1921, English physician ROSENBACH, Ottomar, 1851-1907, German physician Sources: Critchley, M. 1978; Friel, J. P. 1974; Landau, S. I. 1986; Stedman, T. L. 1976.
Detection and Estimation
Published in Shaila Dinkar Apte, Random Signal Processing, 2017
The characteristic properties of linear systems do not always remain constant. The properties change with time. Consider the example of a speech signal. This is a naturally occurring signal. It has some random components. There is the voice box called the larynx that has a pair of vocal folds. These vocal folds generate excitation in the form of a train of impulses that passes via a linear system called the vocal tract. The train of impulses convolves with the vocal tract response to generate speech. Speech properties obviously change with time as we utter different words. The properties of vocal tract, that is, its impulse response, vary with time. The linear system of the vocal tract will then be a linear but time-varying (LTV) system. When we speak, we utter different words. This is possible because we can change the resonant modes of the vocal cavity and we can stretch the vocal cords, to some extent, to modify the pitch period for different vowels. Thus, the speech signal can be described by a time-varying model (LTV system). The impulse response is time varying, as shown in Figure 4.4.
On the variation of fricative airflow dynamics with vocal tract geometry and speech loudness
Published in Aerosol Science and Technology, 2022
Amir A. Mofakham, Brian T. Helenbrook, Byron D. Erath, Andrea R. Ferro, Tanvir Ahmed, Deborah M. Brown, Goodarz Ahmadi
Voiced speech is produced as lung pressure drives airflow through the vocal folds, which are located in the larynx, inciting self-sustained oscillations. The resultant unsteady modulation of the flow creates an oscillatory pressure field that acts as an acoustic source. Different sounds are produced by altering the vocal tract shape, thereby changing the resonances. Unvoiced speech sounds, classified as such because the vocal folds do not oscillate, are produced due to purely aerodynamic sound sources within the vocal tract. For example, fricatives are consonant sounds that are produced by passing air through a partial restriction in the vocal tract made by placing two articulators close together (Stevens 1999), as occurs during the pronunciation of [f]; a labiodental fricative whose constriction is generated as the lower lip is located against the upper teeth. Similarly, is a dental fricative generated by locating the tip of the tongue against the upper teeth (Isshiki and Ringel 1964). With respect to speech as a modality for transport of infectious disease, fricatives are of interest because, during pronunciation, the constrictions created at the mouth result in increased airflow velocities (Yoshinaga, Nozaki, and Wada 2019b; Pont et al. 2019).
Simplified cerebellum-like spiking neural network as short-range timing function for the talking robot
Published in Connection Science, 2018
The talking robot consists of an air pump, an artificial vocal cord, a resonance tube, an artificial nasal cavity, and a microphone connected to a sound analyser, which represents the lung, vocal cord, vocal tract, nasal cavity and auditory feedback of a human, respectively. An air compressor provides the airflow for the talking robot. The airflow is directed to the vocal cords via a pressure control valve and two control valves. These work as controllers for the volume of voiced sound and unvoiced sound. The resonance tube works as a vocal tract and is attached to the artificial vocal cord for the manipulation of resonance characteristics. The nasal cavity is connected to the resonance tube with a rotary valve between them. The microphone and amplifier acts as an auditory system for the feedback during speech. The relation between the voice characteristics and the motor control commands are stored in the system controller, which is referred to the generation of speech articulatory motion. The overview of the system is shown in Figure 1. The characteristics of a glottal wave, which determines the pitch and the volume of the human voice is governed by the complex behaviour of the vocal cord-the oscillatory mechanism of human organs consisting of a mucous membrane and muscles excited by airflow from the lung. The vibration of a 5 mm width rubber band attached to a plastic body creates sound from the artificial vocal cord.
Impulsive Behavior Detection System Using Machine Learning and IoT
Published in IETE Journal of Research, 2021
Soumya Jyoti Raychaudhuri, Soumya Manjunath, Chithra Priya Srinivasan, N. Swathi, S. Sushma, Nitin Bhushan K. N., C. Narendra Babu
Various algorithms have been designed by the researchers based on the variations in the facial muscles, gestures and variations in the speech and voice signals to recognize speaker, emotions and the content. In Reference [14], stress levels were extracted using facial expressions, gestures, voluntary and involuntary changes in eyes, mouth, movement of head through videos and images. Sound is produced by pockets of air emanated by resonance of the vocal cords and transformed into speech by the vocal tract. Changing levels of stress vary the patterns of respiration in turn causing changes in pitch level, pronunciation and expression patterns in the speech [15].