Speech Science Chapter 5

What is Bernoulli principle, and how it applicable in phonation?

According to this principle, air passing through narrow channel increases in velocity and decreases in pressure Decrease in pressure between VFs helps to close them by pulling them toward each other The air that has already passed through the glottis travels up the vocal tract The distance between the traveling body of air and the glottis increases, resulting in a negative pressure directly above the glottis. This supraglottal negative pressure also reinforces the VF closure

What is the difference between a hoarse and a breathy voice?

Breathy voice: when the vocal folds do not close properly, the result is a continuous flow of air during the entire vibratory cycle. The air leaking out generates a hissy kind of friction noise along with the tone generated by the vibrating vocal folds. Rough or Hoarse voice: A very common symptom of most laryngeal disorders Partly, hoarseness is determined by the periodic vibration of the vocal folds. As aperiodic sound is noise, it results in the perception of the noise component in the voice. Hoarseness tends to be associated with increased noise at lower frequencies (100-2600 Hz)

What is the modal register and explain its physiologic and acoustic bases?

Commonly used in conversational speech This register is characterized by full participation of the cover and body during vibration Individuals can generate the greatest range of amplitude in this register The VFs are somewhat shorter in length compared to their nonvibrating position, the cover is slack, and the body is full involved in vibration The duty cycle is characterized by relatively longer closing phase and a short closed phase

What is MATP?

The Myoelastic-Aerodynamic Theory of Phonation is the most accepted model of voice production, This model described voice production as an interaction of muscle force (myo), tissue elasticity (elastic), and air pressures and flows (aerodynamic).

What is vertical phase difference?

This time lag between the opening and closing of the inferior and superior portions of the vocal f old is known as vertical phase difference

What is a mucosal wave?

This time lag between the opening and closing of the inferior and superior portions of the vocal fold is known as vertical phase difference. Vocal folds open from their posterior attachment at the vocal processes to the anterior portion at the anterior commissure. Vocal folds close in an anterior to posterior direction. This time lag in closure is known as longitudinal phase difference. These timing differences give the vibrations of the vocal folds a smooth, wavelike motion known as the mucosal wave.

What is the falsetto register and explain its physiologic and acoustic bases?

Very high range of F0 Falsetto is characterized by very high fundamental frequencies, extremely tense vocal folds, a less complex mode resulting in a thin quality To achieve this register, the CT muscle exerts a great deal of longitudinal tension The cover of the VFs is lax, while the vocal ligaments is tensed

What is the pulse register and explain its physiologic and acoustic bases?

Very low range of F0, a creaky sounding voice The VFs are short and thick The false VFs may come into contact with true VFs, thus increasing the vibrating mass and further decreasing the F0 This register is determined by a very low range of fundamental frequencies and a long closed phase, as well as biphasic or multiphasic closure That is, instead of just opening and closing, they open, close slightly but not all the way to the midline, open again, and then close all the way and stay closed for 90% of the cycle

What is longitudinal phase difference?

Vocal folds close in an anterior to posterior direction. This time lag in closure is known as longitudinal phase difference.

What are the six parameters of voice that contribute to a normal, clear, vocal quality

1. Maximum frequency range (adults - two to three octaves) 2. Average fundamental frequency 3. Maximum phonation time (15 - 25 sec) 4. Minimum-maximum intensity (20 -30 dB) 5. Periodicity of VF vibration (Jitter) 6. Noise

What are the steps of MATP?

1. Vocal folds (VFs) must close to initiate the vibration This is achieved by the LCA and IA muscles, which exert a force called medial compression 2. Medial compression holds VFs closed at the midline This causes air pressure beneath the VFs (subglottal pressure, Ps) to increase 3. When Ps is strong enough, it forces the closed vocal folds apart 4. Puff of air escapes into the vocal tract - sets air within tract into vibration 5. Sound wave is transmitted through the vocal tract where the valves will modify the sound 6. Meanwhile, the VFs have begun to adduct again due to interactions of two forces: a. Recoil back to midline due to natural elasticity. As they begin to close, they form a narrow channel when they close. b. The air passing through the constriction formed by the closing glottis becomes negative in pressure due to the effect of Bernoulli principle. 7. Once the glottis is closed by elasticity and negative pressure, Ps builds up and the whole process repeats.