Abstract
The three parameters of phonation, i. e. intensity, fundamental frequency, and air flow rate were simultaneously measured in 50 normal adults and 134 cases with various laryngeal disorders, using a phonation function analyzer (PS-77, Nagashima Co.). The subjects were required to hold a mouth-piece attached to a hot-wire flow meter and sustain the vowel /a/ in a comfortable fashion. The fashion of the phonation was observed to be consistent with the factors indicating individual differences such as height, weight and age in normal subjects. When the multiple regression analysis was performed among the three parameters of phonation, the multiple correlation held good (Male: 0.829, P<0.01, Female: 0.527, P<0.05). The multiple regressive expressions acquired were as follows.
Male: I=13.2log u+22.6log f0-2.5
Female: I=7.7log u+40.1log f0-39.1
u: flow rate (ml/sec), f0: fundamental frequency (Hz), I: intensity (dB SPL)
In pathological cases, estimated loudness was derived from the regressive expression, and the difference between the measured and the estimated values of loudness was calculated. The difference was considered to reflect the efficiency of phonation and to be comparable to the condition of various laryngeal pathologies.
