Abstract
We investigated the relationship between the acoustical characteristic of the nasalized vowels and the velopharyngeal incompetence (VPI) of cleft palate patients. Subjects were five male adult patients who had palatoplasty in their infancy. Cephalograms, digital recordings of Japanese vowels and magnetic resonance imaging (MRI) of head and neck were taken from sublects. MRrs were obtained while the patients pronounced single vowels nonnally. We employed the A-b-S (Analysis-by-Synthesis) method for the acoustical analysis of the / i / sound with our original software in a work station. The velopharyngeal opening areas were measured with a personal computer by using MRI’s of the velo-pharyngeal closure portion.The results showed that the antiformant frequencies were related to the velopharyngeal opening area, and the antiformant frequencies will be a useful index to VPI case. The acoustical estimation of the velopharyngeal opening area will apply to the training of speech improvement.However, to fully determine the relations between the antiformant frequencies and the velopharyngeal opening area, the followings are required, 1) measuring the entire area of the vocal tract including asymmetrical anomalous nasal passages and paranasal cavities, and 2) avoiding the artifact of MRI.
