Phonatory characteristics of excised pig, sheep, and cow larynges. (65/317)

 (+info)

Estimating subglottal pressure via airflow interruption with auditory masking. (66/317)

 (+info)

An automatic method to quantify mucosal waves via videokymography. (67/317)

 (+info)

Acute effects of radioiodine therapy on the voice and larynx of Basedow-Graves patients. (68/317)

 (+info)

Botulinum toxin in speech rehabilitation with voice prosthesis after total laryngectomy. (69/317)

 (+info)

Chaotic component obscured by strong periodicity in voice production system. (70/317)

The effect of glottal aerodynamics in producing the nonlinear characteristics of voice is investigated by comparing the outputs of the asymmetric composite model and the two-mass model. The two-mass model assumes the glottal airflow to be laminar, nonviscous, and incompressible. In this model, when the asymmetric factor is decreased from 0.65 to 0.35, only 1:1 and 1:2 modes are detectable. However, with the same parameters, four vibratory modes (1:1, 1:2, 2:4, 2:6) are found in the asymmetric composite model using the Navier-Stokes equations to describe the complex aerodynamics in the glottis. Moreover, the amplitude of the waveform is modulated by a small-amplitude noiselike series. The nonlinear detection method reveals that this noiselike modulation is not random, but rather it is deterministic chaos. This result agrees with the phenomenon often seen in voice, in which the voice signal is strongly periodic but modulated by a small-amplitude chaotic component. The only difference between the two-mass model and the composite model is in their descriptions of glottal airflow. Therefore, the complex aerodynamic characteristics of glottal airflow could be important in generating the nonlinear dynamic behavior of voice production, including bifurcation and a small-amplitude chaotic component obscured by strong periodicity.  (+info)

Qualification of a quantitative laryngeal imaging system using videostroboscopy and videokymography. (71/317)

OBJECTIVES: We sought to determine whether full-cycle glottal width measurements could be obtained with a quantitative laryngeal imaging system using videostroboscopy, and whether glottal width and vocal fold length measurements were repeatable and reliable. METHODS: Synthetic vocal folds were phonated on a laboratory bench, and dynamic images were obtained in repeated trials by use of videostroboscopy and videokymography (VKG) with an imaging system equipped with a 2-point laser projection device for measuring absolute dimensions. Video images were also obtained with an industrial videoscope system with a built-in laser measurement capability. Maximum glottal width and vocal fold length were compared among these 3 methods. RESULTS: The average variation in maximum glottal width measurements between stroboscopic data and VKG data was 3.10%. The average variations in width measurements between the clinical system and the industrial system were 1.93% (stroboscopy) and 3.49% (VKG). The variations in vocal fold length were similarly small. The standard deviations across trials were 0.29 mm for width and 0.48 mm for length (stroboscopy), 0.18 mm for width (VKG), and 0.25 mm for width and 0.84 mm for length (industrial). CONCLUSIONS: For stable, periodic vibration, the full extent of the glottal width can be reliably measured with the quantitative videostroboscopy system.  (+info)

An acoustic analysis of laughter produced by congenitally deaf and normally hearing college students. (72/317)

 (+info)