ヒト生体の声帯物性 正常者の場合

Abstract

The resonance frequency, Q-value of resonance and damping ratio of the vocal fold were estimated in living humans using the ultrasonic pulse method. In the present study, the transducer was placed on the thyroid lamina so that the ultrasonic beam would irradiate the margin of a vocal fold perpendicularly. A vibrator is placed on the skin over the midline of the thyroid cartilage to provoke an oscillation with the frequencies ranging from 30 to 300Hz continuously. The resonance pattern of vocal fold was recorded in the quiet inspiratory phase or in the phase of phonation neutral. The results obtained were as follows:1) The resonance frequency of the thyroid cartilage was found in the range between 70 and 80Hz, and the Q-value between 2 and 3, while the resonance frequency of the vocal fold was found in the range of 110-120Hz with the Q-value of 4-6. 2) Little difference was observed regardless of the site of the vibrator and the transducer. The resonance frequency of the vocal fold was usually found in the range of 100-110Hz during quiet respiration.3) Resonance frequencies and Q-values in the excised larynges were approximately 100Hz and 2.2-2.9, respectively.4) In male adults, resonance frequencies of the vocal fold ranged from 91 to 145Hz(average 128Hz), and in female adults, 115-167Hz (average 136Hz), while Q-values ranged from 2.1 to 5.1 (average 3.4) in male, and 2.6-7.1 (average 4.0) in female. 5) In a male vocal fold, during phonation neutral at low pitch, only one resonance occurred at a frequency value close to the phonation pitch. However, two resonance points were usually observed in a female vocal fold and also in a male vocal fold at high pitch. The second resonance frequency was almost equal to the phonation pitch. Regarding the Q-value, no significant differences were found between the two resonance points. at a frequency value close to the phonation pitch. However, two resonance points were usually observed in a female vocal fold and also in a male vocal fold at high pitch. The second resonance frequency was almost equal to the phonation pitch. Regarding the Q-value, no significant differences were found between the two resonance points.