Chapter 6 Flashcards
(70 cards)
Measurement of f0 and intensity can be divided into three categories. Name them.
The three categories of measurement of f0 and intensity are levels of habitual voice use (how the voice performs under routine use), levels of maximum performance (how the voice performs under stress; the limits of the system), and degree of regularity (how stable the voice production system).
Define mean speaking f0 and mean speaking f0 range.
Mean speaking f0 is the average fundamental frequency that we speak at, and mean speaking f0 range is the range within which we usually speak.
Define perturbation, jitter, and shimmer.
Perturbation is just any irregularity or variability in a certain system, jitter is the measurement of any short-term fundamental frequency perturbation (variability) during sustained vowel phonation, and shimmer is the measurement of any short-term variability in the amplitude of an acoustic waveform, measured from steady sustained vowel phonation.
What is a voice range profile?
A voice range profile is a graphical representation of the relationship between f0 and intensity.
What is the difference between voice range profiles elicited from men and women?
Men generally have a higher intensity (due to greater lung capacity and therefore pressure) and a lower frequency (due to a longer vocal tract). Women tend to have less intensity than men and a higher frequency.
What physiologic factors contribute to the general shape of the voice range profile (for example, why does the lower contour curve upward with increasing frequency?)?
The three notable features that influence intensity as seen in a voice range profile are that one, the wider the area, the more flexible the voice (because the intensity and pitch ranges are larger), two, that this dynamic range we see is reduced at both the upper and lower extremes, and is widest around the more middle frequencies (lower frequencies make maintenance of intensity hard because of the necessity for the vocal folds to remain relaxed and in a slower rate of vibration, and higher frequencies require greater lung pressure, and thus, greater intensity), and third, both the upper and lower contours tilt upward in the higher frequencies (people can phonate more loudly at higher frequencies because there’s greater lung pressure).
In general, how is mean airflow measured?
Generally, mean airflow is measured as it exits the oral and nasal cavities, measured as the volume of air that passes a given point (mL per sec).
How can lung pressure be measured from intraoral pressure?
When the vocal folds are open and the lips and nasal passages are sealed, the pressure in the vocal tract is all the same. So then the pressure measured (the intraoral pressure) during the production of a /p/ phoneme is assumed to be equal to the lung pressure produced during the adjacent vowel. This test is measured by inserting a pressure transducer into the mouth.
Define vocal efficiency and glottal efficiency.
Vocal efficiency is the ratio of the radiated acoustic power to the aerodynamic power, which is mean lung pressure times mean glottal flow. Glottal efficiency is the ratio of aerodynamic power to acoustic power at the level of the glottis. Efficiency overall is just the ratio of the output of a system to the input. We are measuring how efficiently the voice/glottis are functioning.
What factors can affect vocal efficiency?
Voice disorders can affect vocal efficiency, usually because of the higher airflow rate and incomplete glottal closure, which means less excitation of the air in the vocal tract.
Explain the s/z ratio. What are some threats to the validity of this measure?
The s/z ratio measures the relative durations of the /s/ and /z/ phonemes and is used to assess glottal closure during phonation. Some threats to validity are the inconsistency of elicitation procedures and a lot of variability in results. Also, certain variables can alter the length of the production of these phonemes, such as the inspiratory checking action (which can aid in holding the phoneme for longer) and supraglottal muscle constriction, which will affect results.
Define maximum phonation time and provide average values for children, men, and women.
Maximum phonation time is the amount of time that an individual can hold a maximally sustained vowel. The average values are as follows:
Children
- 6 y - 10.4 s (boy), 10.6 s (girl)
- 10 y - 22.2 s, 15.9 s
- 15 y - 20.7 s, 19.5 s
Adults
- Men 17-41 y - 24.9
- Women 18-40 - 17.9
How do practice effects and elicitation methods influence values of maximum phonation time?
With practice and repetition, an individual can improve their scores, and through the method of elicitation, they can also affect their scores because if the individual is not actually producing a fully sustained vowel they could improve their score the next time they perform the test, So it’s a popular measure, but may not be the best test.
Define phonation quotient.
Phonation quotient is vital capacity divided by the maximum phonation time (in mL per sec). It’s a good measure of the volume of air used as a function of sustained phonation.
Explain stroboscopy: the instrumentation used, how it works, and what type of image it provides.
Stroboscopy is the process of using a pulsing light to simulate movement at a rate slower than the actual rate of movement of the object being imaged. It works because the image is illuminated uniformly (without the perception of variation), and motion is perceived from sampling images at specific points in time. The rate of flashes of light is slightly lower than the actual vibratory rate of the vocal folds, allowing for a slight differentiation in cycle movement (not equal because then it would capture the same point on every cycle). This is done using an endoscope.
What is a weakness of stroboscopy with respect to aperiodic vibration?
Because the stroboscopy relies on the brain stringing together images from the various points of vocal fold movement, the more aperiodic the vibration, the less accurate the representation by the stroboscopic images, because the irregularity of the vibration results in difficulties synchronizing the rate of the strobe-light pulses to the rate of the vibrating vocal folds.
How is high-speed laryngeal imaging different from stroboscopy?
High-speed laryngeal imaging has a faster capture rate and can therefore more accurately capture even the highly irregular vibrations of the vocal folds. But, the image sharpness is still below that of stroboscopy.
Define videokymography.
Videokymography is based on the acquisition of images at a very rapid rate, but it only images a section of the vocal folds rather than the entire area.
Define photoglottography and explain its limitations.
Photoglottography provides information about the relative size of the glottal opening by measuring the amount of light that passes through the vocal folds during each vibratory cycle. Its limitations are its invasiveness, its provision of only relative, not absolute, amount of light passing through the glottis, and the fact that the light sensor may not accurately register the light transmitted through the glottis.
Explain the theoretical vocal fold positions at each of the five marked points on the waveform in Figure 6-9.
OPEN
Bottom touching
CLOSED
Top touching
Initial separation
What are the advantages and weaknesses of electroglottography?
Electroglottography provides a waveform that has been shown to correspond to the relative contact of the vocal folds during vibration. Its advantages are that it’s easy to use, relatively inexpensive, readily available, and noninvasive. Its issue is that interpretation of the waveform in those with voice disorders is hard and its reproduction of the appropriate phases of the vocal fold cycle is often done imprecisely.
Define open, speed, and contact quotients.
The open quotient is the ratio of the open phase of vocal fold vibration to the entire glottal cycle. The speed quotient is the ratio of the duration of the opening phase of the vocal folds to the duration of the closing phase. The contact, or closed, quotient is the ratio of the time the vocal folds are in contact to the entire glottal cycle.
What is register? Why is it conceptually controversial?
Register refers to three modes of vibration of the vocal folds. It is a controversial topic because how to differentiate between the registers and even what to call them is debated by many people. This is for several reasons. First, registration is a psychoacoustic phenomenon, which means register is based on perceptual judgments, which will vary from person to person. Second, the physiology and acoustics of the different registers are not fully understood. Third, register is not only used to refer to the quality change of the vocal fold vibration but also may refer to the voice quality change due to f0 alone. Fourth, the registers used in singing are different from those for speaking, but the terms overlap. Fifth and finally, the confusion with the distinction between normal and abnormal vocal fold vibration; register is usually restricted to the different qualities observed during normal modes of vibration.
What is the relevance of the term “quantal change” to register?
A quantal change refers to an abrupt transition from one state to another due to a continuously changing variable. Transitions between registers are quantal changes, with the underlying continuously changing variables are f0 and other vibratory characteristics of the vocal folds.
