Volume 103, Issue 6, June 1998
Index of content:
- SPEECH PRODUCTION 
103(1998); http://dx.doi.org/10.1121/1.423067View Description Hide Description
Videostroboscopy is an examination which yields a permanent record of the moving vocal folds. Thus, it allows the diagnosis of abnormalities which contribute to voice disorders. In this paper, in order to find and quantify the deformation of the vocal folds in videostroboscopic recordings, an active contours- (snakes) based approach is used to delineate the vocal folds in each frame of the videostroboscopic image sequence. After this delineation, a new elastic registration algorithm is used to register the vocal fold contours between adjacent frames of the video sequence. This algorithm is based on the regularization principle and is very effective when large deformations are present. A least-squares approach is used to fit an affine model to the displacement vectors found by elastic registration. The parameters of this model, rotation, translation, and deformation along two principle axes, quantify the deformation and allow the succinct characterization of the videostroboscopic recordings based on the deformations that occurred. Experiments are shown with synthetic and real videostroboscopic data that demonstrate the value of the proposed approach.
103(1998); http://dx.doi.org/10.1121/1.423068View Description Hide Description
Age-related changes in the laryngeal system can be perceived as altered vocal pitch and increased pitch variability. However, reports vary as to the nature and extent of an age effect on fundamental frequency for analyses taken over long segments of connected speech.Analysis of across a smaller time frame may be more informative. Young speakers show an increase in associated with phonetically governed devoicing gestures that is likely mediated by increased vocal fold stiffness. Anatomic and neurophysiologic changes in the aged larynx may limit the role of increased vocal fold stiffness in the devoicing gesture. This study tests the hypothesis that aged speakers show a smaller increase in in association with the devoicing gesture for production of an intervocalic voiceless obstruent than do young speakers. Normal young and aged speakers produced a short sentence containing an intervocalic voiceless obstruent. Measures of were obtained for ten cycles before voice offset and ten cycles after voice onset. Young speakers showed a small increase in during devoicing whereas aged speakers showed a decrease in during devoicing. Aged speakers seem to rely more on vocal fold abduction rather than a combination of abduction and tensing to achieve devoicing.