Abstract
The aerodynamic measurements were performed to examine the intensity and pitch regulation mechanism in voice production. The intensity of voice was proportional to 3.5±1.6 power of the subglottic pressure with males and 3.9±2.9 power of it with the females. The volume velocity of exhaled air generally increased as the intensity increased, and the intensity of voice was proportional to 3.6 power of the volume velocity with the males and 7.0 power of it with the females. But in some cases, especially in the phonation at lower pitches, the volume velocity was costant or slightly decreased as the intensity increased. The glottal resistance did not exhibit a close correlation with the intensity and the pitch of voice. In general, the change of resistance in the regulation of intensity was less with the males than with the females. The subglottic power in a given intensity was less with the males than with the females. The glottal efficiency was not constant but changed as the intensity varied. The intensity of voice was proportional to 1.7-9.3 power of the glottal efficiency with the males and 1.2-6.0 power of it with the females.
The glottal efficiency of the patients with voice disorder was not so different from the normal as it has been expected. To discuss this result another experiment was intended, and the influences of the mode of phonation upon the aerodynamic parameters were investigated. The change of the mode of phonation brought about considerable changes of glottal efficiency, phonation length and others.
The glottal efficiency changed along with the subglottic pressure in pressed phonation, and it changed along with the glottal resistance in breathy phonation. From this fact, the author concluded that the exertions play a principal part in the regulation of the intensity and pitch of voice. In some cases the glottal exertion (glottal resistance) will dominate and in other cases the expiratory exertion (subglottic pressure) will do.
The subglottic pressure was minimum at natural pitch and it increased as the pitch became higher. The volume velocity slightly increased according as the pitch became higher with the males, while it slightly decreased with the females. It was proved that the natural phonation (in normal intensity and at natural pitch) is the most rationalistic way for speech from a viewpoint of the aerodynamic aspect of voice regulation.
The compensation of the glottal function in voice disorder may be attributed to the change of the mode of phonation. It followed that in the clinical examination of voice disorder we must pay attention to the change of the mode of phonation, that is, the change of exertions.
The author wishes to express his gratitude to Professor S. Kawata for the valuable guidance and encouragement.
