Exercise-induced stridor due to abnormal movement of the arytenoid area: videoendoscopic diagnosis and characterization of the "at risk" group.

We evaluated 4 patients who developed severe, symptomatic stridor during maximal cardiopulmonary exercise testing, all referred due to exercise-related dyspnea. All underwent resting, unsedated transnasal fiberoptic laryngoscopy and had normal findings. Four patients performed repeat maximal exercise testing with fiberoptic laryngoscopy, and they form the basis of this report. They had normal vocal cord motion during exercise, but developed abnormal anterior motion of the arytenoid and aryepiglottic folds only at peak exercise, leading to partial airway obstruction and severe stridor. This report details the workup and characterizes patients at risk for this unusual phenomenon.

MRI evaluation of vocal fold paralysis before and after type I thyroplasty.

Magnetic resonance imaging (MRI) is a useful modality for three-dimensional evaluation of laryngeal anatomy. The authors present data on patients with unilateral vocal fold paralysis both before and after type I thyroplasty for medialization. Videoendoscopic and acoustic measures were obtained. MRI was performed preoperatively and postoperatively. Three-dimensional descriptive parameters were established to assess implant location. As well, vocal and endoscopic assessment were used to determine a successful result. Magnetic resonance images of two patients with satisfactory results were compared with images and vocal analysis of two dissatisfied patients. Use of MRI after type I thyroplasty provides additional information about implant location that can help determine the cause of poor results.

Analysis of vocal tract shape and dimensions using magnetic resonance imaging: vowels.

Magnetic resonance imaging (MRI) techniques were used to gather basic data to apply in computational models of speech articulation. Two experiments were performed. In experiment 1, voice recordings from two male subjects were obtained simultaneously with axial, coronal, or midsagittal MR images of their vocal tracts while they produced the four point vowels. Area functions describing the individual tract shapes were obtained by measurements performed on the MR images. Digital filters derived from these functions were then used to resynthesize the vowel sounds which were compared, both perceptually and acoustically, with the subjects' original recordings. In experiment 2, axial images of the pharyngeal cavity were collected during the production of an ensemble of nine vowels. Plots of cross-sectional area versus the midsagittal width of the tract at different locations within the pharynx and for different vowel productions were used to derive a functional relationship between the two variables. Data from experiment 1 relating midsagittal width to cross-sectional area within the oral cavity were also examined.