声門下圧と音声波形の同時測定によるリサージュ図形的検討

概要

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In the present report, a newly developed method for direct measurement of subglottal pressure is described, which is consisted of a fiberoptic catheter with both inlet and outlet glass fibers and an optical reflector. In addition, subglottal pressure and a wave form of the sound produced in an isolated canine larynx were analysed on the basis of Lissajous figure.<BR>In the case of normal vocal cords, a distortion in the Lissajous figure of the sound wave and subglottal pressure is observed according to augmentation of the air flow. However, the sound intensity is gradually increased in proportion to augmentation of the air flow. No phase shift between the sound wave and vibratory variation of subglottal pressure is observed.<BR>In the case of abnormal vocal cards, higher stiffness of membranous portion of the vocal cord results in increase of phase difference between the sound wave and vibratory variation of subglottal pressure. No increase of sound intensity is observed even when high volume of air flow is employed for sound production.<BR>These analyses mentioned above are very easily obtained by use of Lissajous figure method.