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66 The Voice and Voice Therapy
The principles governing changes in voice quality are less concrete and more elusive compared
to those of pitch and loudness. This ambiguity is partly due to the subjective nature of voice quality
assessment. Perceptions of voice quality vary widely among listeners; what is deemed pleasant or
acceptable to one individual may be perceived differently by another. This subjectivity extends
to the terminology used to describe voice quality. Two listeners may agree on the characteristics
of a particular voice yet describe it using entirely different terms. This variability underscores the
complexity of voice quality and its assessment.
Abnormal voice quality may be a hallmark feature of dysphonia, regardless of etiology. In our
clinical practice, we see patients who present with a voice that is breathy, rough, strained, harsh
(strained and rough), or hoarse (strained, rough, and breathy). Each of these vocal qualities can
result from functional, organic, or neurological causes, or some combination of causes. Most of
the voice facilitating approaches described in Chapter 7 can be used to improve voice quality,
particularly the abnormal voice qualities that result from vocal hyperfunction.
Breathy voice quality is often associated with incomplete glottal closure. When the vocal folds
are loosely or incompletely approximated, turbulent airflow contributes noise to the vocal signal.
Intensity is diminished. Rough voice quality is often associated with aperiodic vocal fold vibration.
The irregular mucosal wave movement adds spectral noise. Intensity may be increased. Strained
voice quality is often associated with considerable medial compression of the true (and perhaps
false) vocal folds. Strained voice quality is also often associated with aperiodic vocal fold vibration,
which adds spectral noise. Intensity may be increased. The four spectrograms in Figure2–20
contrast the breathy voice, the harsh voice, the hoarse voice, and the normal voice. Each of the
spectrograms was produced by the same normal speaker producing an /i/.
Perkins (1983) has added constriction and vertical as well as horizontal focus to the concept
of voice quality production. He describes the voice facilitating approach of yawn-sigh, discussed
in Chapter 7, which demonstrates the clinical value of these physiological configurations of the
supraglottal vocal tract. Imagery or feeling is used to determine the vertical focus of the voice,
“the perception associated with the placement of the focal point of the tone in the head” (Perkins,
1983, p. 113). At the low end of the vertical focus, speakers or singers feel their voice is being
squeezed out of the throat, whereas at the high end, the focus seems to be high in the head. The
sensation is described as if the tone were “floating in the head.” Vocal efficiency seems to occur best
at the higher end of the vertical placement. The voice facilitating approach of focus, discussed in
Chapter 7, makes use of these observations. It has been our experience that subjects given these
instructions relative to the imagery of constriction and verticality produce voices with greater
aperiodicity (hoarseness) at the low end of the vertical scale and greater vocal clarity at the high
end. In time, Perkins’s construct of constriction and horizontal as well as vertical focus may well
have greater measurement potential and utilization.
Resonance
The acoustic signal produced by the vocal folds would be a weak-sounding reedy voice without the
additional component of resonance. Years ago, one of the authors of this text observed a patient
who had been cut from ear to ear with a massive wound that opened immediately superior to his
thyroid cartilage. Before the wound was sutured, we heard the patient’s feeble attempts at phonation. Much of his airflow and sound waves escaped through the wound. The result was a voice
that was truly unique. Someone even likened it to the thin bleat of a baby lamb. Apparently, what
CHAPTER 2 Normal Voice: Anatomy and Physiology Throughout the Lifespan 67
FIGUR E 220. Spectrograms. Four spectrograms of the same speaker producing the /i/ vowel
under four conditions: breathy (top left), normal (top right), harsh (bottom left), and hoarse
(bottom right). The relative spacing of the formants stays the same as the signal source changes.
is perceived as the quality, timbre, richness, fullness, and loudness of the voice is largely produced
by the supraglottal resonators. Even though the structures of the chest and trachea may play some
role in resonance, this role is not as clearly defined as that of the supraglottal resonators of the
pharynx, oral cavity, and nasal cavity. Figure2–21 shows a line drawing and cadaver head that
demonstrates the F-shaped vocal tract.
68 The Voice and Voice Therapy
A
FI GUR E 2 21. A. The F-shaped vocal tract. The F-shaped vocal tract is
shown in both the photograph of a cadaver head in part A of this figure and
the line drawing in part B. Letters A through Q identify various structures
of the vocal tract: (A) true folds, (B) ventricular space, (C) ventricular folds,
(D) epiglottis, (E) aryepiglottic folds, (F) hypopharynx, (G) inferior pharyngeal
constrictors and upper esophageal sphincter, (H) middle pharyngeal constrictors, (I) valleculae, (J) oropharynx, (K) mandible, (L) tongue, (M) Passavant’s
pad, (N) soft palate (velum), (O) hard palate, (P) nasopharynx, (Q) nasal
cavity.
continues
CHAPTER 2 Normal Voice: Anatomy and Physiology Throughout the Lifespan 69
B
FI GUR E 2 21.
Structures of Resonance
The vocal tract begins, for all practical purposes, at the level of the glottis. The airflow and sound
waves probably have some beginning passage in the ventricular space (in Figure 2–21) between
the true folds (A) and the ventricular folds (C). In Figure 2–21, the cavities of the vocal tract have
been shaded darker. The epiglottis (D), by its concavity, probably serves as a deflector or soundingboard resonator as sound waves travel between the aryepiglottic folds (E) into the hypopharynx
(F). The hypopharynx is the cavity directly above the esophagus (G). Its anterior border comprises
the structures and opening of the larynx; its sides and back wall are composed of the inferior
pharyngeal constrictors. Superior to the inferior pharyngeal constrictors are the middle pharyngeal
constrictors (H). The oropharynx (J) begins at the tip of the epiglottis and extends to the level of
the velum and hard palate. The small angular spaces between the front of the epiglottis and the
back of the tongue (L) are called the valleculae (I). Cutting away the mandible (K) in a lateral view
is the great body of the tongue, which occupies most of the oral cavity and forms the constantly
changing floor of that cavity. The hard palate is designated (O), with the soft palate or velum, (N)
forming the roof of the oral cavity. The lips, teeth, and cheeks play obvious front and lateral roles
continued
B. The vocal tract.
70 The Voice and Voice Therapy
in shaping the oral cavity. The middle and superior pharyngeal constrictors form the lateral and
posterior muscular wall of the oropharynx (J). The site of the velopharyngeal closure, necessary
for the separation of the oral and nasal cavities required for oral resonance, is the Passavant’s pad
(M) area of the superior pharyngeal constrictor; most people do not have much Passavant area
enlargement. As shown in Figure 2–21, superior to the velopharyngeal contact point, the posterior
pharyngeal wall makes a sharp angulation forward, forming the superior wall of the nasopharynx
(P) and continuing as the superior wall of the nasal cavity. We make no further structural breakdown of the nasal cavities (Q) as a prelude to our discussion of resonance. Note that Figure 2–21
also shows the lateral walls, pillars of fauces, and muscles of the palate, pharynx, and tongue. If
we look again at the overall lateral view of the vocal tract, we see that the total darkened areas
look something like a large letter F. The vocal tract in the photograph resembles an F because the
velopharyngeal port is open, connecting the oral and nasal cavities. If the port were closed at the
velopharyngeal contact point (M), the vocal tract opening available for voice resonance would
resemble the letter r, which is formed only by the pharynx and the oral cavity opening above the
surface of the tongue.
Mechanism of Resonance
In humans, the larynx is situated at approximately the fifth cervical vertebra, thus creating a resonating chamber to filter and amplify the acoustic signal. Some areas of the vocal tract, depending
on their configuration, are compatible with the periodic vibration coming from the vocal folds
and amplify the fundamental frequency and its harmonics. For example, a fundamental frequency
of 125 Hz will resonate harmonic frequencies at 250, 375, 500 Hz (each subsequent harmonic
frequency is a whole number multiple of the fundamental), and so on. For a more detailed description of vocal tract acoustics, the reader is referred to sources such as Baken (1996), Borden and
colleagues (1994), Minifie (1994), and Kent and Read (2002). The continuous vocal tract tube
is constantly interrupted at various sites from the intrusion and movement of various structures.
Some of the interruptions or constrictions may be severe, such as carrying the tongue high and
forward in the oral cavity. Any movement of mandible, tongue, or velum, for example, will greatly
alter the opening of the oral cavity. Some of the movements have no effect on the fundamental or
sound source; some of them filter or inhibit the fundamental.
What finally comes out of the mouth or the nasal cavity perceived as voice has become a
complex periodic signal with the same fundamental frequency as the vocal fold source, but highly
modified in its overall sound characteristics. We can hear several familiar voices all saying the same
few words at the same fundamental frequency, and we are still able to differentiate each voice and
assign it to each familiar person. Even if we do not know the speaker, we can fairly accurately tell
the approximate age and the gender of the speaker. Perhaps even more important, by filtering the
glottal tone, we can tell if the person has a cold or is upset or angry, tired, or frightened. Or the
meaning could even be changed by the change in quality or emphasis while saying the same words.
The vocal characteristics related to the individualization of each person’s vocal tract has given each
voice its own unique characteristics (vocal quality) as the result of the amplification and filtering
unique to each vocal tract.
The F configuration of the supraglottal vocal tract is constantly changing. What happens in
any one portion of the tract influences both the total flow of air and sound waves through the
CHAPTER 2 Normal Voice: Anatomy and Physiology Throughout the Lifespan 71
total tract and the sound that eventually issues out from the mouth (or nose). By action of the
pharyngeal constrictors and other supraglottal muscles, the overall dimensions of the pharynx are
always changing. The membranes of the pharynx and the degree of relaxation or tautness of the
pharyngeal constrictors have noticeable acoustic filtering effects. Higher frequency vocalizations
seem to receive their best resonating effects under a fairly high degree of pharyngeal wall tension.
Lower frequencies appear to be better amplified by a pharynx that is somewhat larger and more
relaxed. This appears to be related to the short wavelength of high-frequency sounds and the long
wavelength of the low-frequency components.
The oral cavity, or mouth, is as essential for resonance as the pharynx. Of all our resonators, the
mouth is capable of the most variation in size and shape. It is the constant size–shape adjustment
of the mouth that permits us to speak or, more accurately, allows us to be understood. Our vowels
and diphthongs, for example, are originated by a laryngeal vibration but shaped and restricted by
the size and shape adjustment of the oral cavity. The mouth has fixed structures (teeth, alveolar
processes, dental arch, and hard palate) and moving structures (tongue, velum, cheeks, mandible,
and lips). We are most concerned with the moving structures, primarily the tongue, velum, and
mandible, in our study of voice resonance. The mouth and other supraglottal resonators give us
the perception of a regional dialect to help identify the speaker and, more important, allow for
the formation of distinguishable vowels.
The tongue is the most mobile articulator, and it possesses both extrinsic and intrinsic muscles
to move it. Each of the extrinsic muscles can, on contraction, elevate or lower the tongue at its
anterior, middle, or posterior points and extend it forward or backward. The intrinsic muscles
control the shape of the tongue by narrowing, flattening, lengthening, or shortening the overall
tongue body and elevating or lowering the tongue tip. The various combinations of intrinsic and
extrinsic muscle contractions can produce an unlimited number of tongue positions with resulting
size–shape variations of the oral cavity. In addition to the tongue movements, the lowering and
closing of the mandible contribute to the formation of specific vowels. The relationships of these
cavities to vowel formants have been described in several references, such as Peterson and Barney
(1952) and Kent and Read (2002).
The structural adequacy and normal functioning of the velum are also important for the
development of normal voice resonance. The elevation and tensing of the velum, as well as some
pharyngeal wall movement, are vital for achieving velopharyngeal closure. A lack of adequate
palatal movement, despite adequacy of velar length, can cause serious problems of excessive
nasality. Although the velum probably serves as a sounding-board structure in resonance, it plays
an obviously important role in separating the oral cavity from the nasal cavity (Abdel-Aziz, 2008).
The movement and positioning of the velum change the size and shape of three important resonating cavities: the pharynx, the oral cavity, and the nasal cavity. Therefore, any alteration of the
velum (such as a soft-palate cleft or velar weakness) may have a profound influence on resonance.
Velar movement is only one component contributing to velopharyngeal closure (Dworkin et al.,
2004). Closure patterns that separate the oral and nasal cavities from one another may include
velar action coupled with posterior pharyngeal wall movement, or velar action coupled with active
lateral and posterior pharyngeal wall movement. McFarlane and Watterson (1990) describe five
classes of velopharyngeal closure and their various effects on speech and voice. Regardless of the
PluralPlus
Self-Check
2–1
type of closure pattern (velar-posterior-lateral pharyngeal wall), the site of closure is generally in
the Passavant’s area (designated as M in Figure 2–21). More will be said of nasal resonance and
of the treatment of hypernasality and hyponasality in Chapters 7 and 10.
72 The Voice and Voice Therapy
Summary
This chapter explored how the respiratory and phonatory systems, along with vocal resonance,
shape the voice, addressing five key voice qualities: loudness, hygiene, pleasantness, flexibility,
and representation. We learned that voice is primarily driven by airflow from the lungs and that
effective voice users must manage their breath well. We discussed the significance of respiratory
volume and examined the normal processes of voice production, including how pitch, loudness,
and timbre are formed. Additionally, we looked at how the vocal tract enhances and modifies
sound. This knowledge forms the foundation for treating voice disorders like dysphonia.
CLINICAL CONCEPTS
The following clinical concepts correspond with many of the objectives at the beginning of
this chapter:
1. Many voice-disordered patients will come to you because one or more of the five
aspects of voice are abnormal. Some examples include a speaker with Parkinson’s
disease who has a soft voice (see Chapter 5); a speaker who is a Marine drill sergeant
and has a voice that gives out before lunch each day (see Chapter 3); a speaker with
a 20-year history of smoking who has Reinke’s edema, resulting in a rough and harsh
voice quality (see Chapter4); a speaker with a traumatic brain injury whose affect is
(emotions are) perceived as flat because they cannot use the voice to express emotion
effectively (see Chapter 5); and a patient who is transgender and is mistaken for the
wrong gender in person and over the telephone (see Chapter 8).
2. Some voice-disordered patients will come to you because they have inadequate
respiratory function for speech and voice. Some examples include a speaker with
a high spinal cord injury who cannot time inhalation/exhalation with voice onset,
resulting in unusual breath group phrasing (see Chapter 5); a speaker with lung
disease, such as chronic obstructive pulmonary disease, who cannot produce a loud
enough voice (see Chapter 8); a geriatric speaker with weak respiratory muscles who
has to take more frequent breaths during talking (see Chapter 8); and a speaker with
spastic dysarthria who cannot control the flow of air through the glottis, resulting in
loudness bursts and harsh voice quality (see Chapter5).
3. Some voice-disordered patients will come to you because they simply have forgotten
how to “take a breath before or during speaking.” These patients talk too long on a single
breath, which results in strained voice quality and decreased loudness (see Chapter 3).
4. Some voice-disordered patients will come to you because they cannot control or
change the pitch of their voice. Some examples include speakers who have paralyzed
vocal folds (see Chapter 5); speakers who have nodules, a polyp, or other mass on
their vocal folds (see Chapters 4 and 9); a patient who is using excessive laryngeal
muscle tension (see Chapter3); and a male speaker who has gone through puberty
but still maintains his juvenile voice (see Chapters 3 and 8).
CHAPTER 2 Normal Voice: Anatomy and Physiology Throughout the Lifespan 73
5. Some voice-disordered patients will come to you because they cannot control or
change the loudness of their voice. Some examples include speakers with Parkinson’s
disease (see Chapter 5); speakers with flaccid dysarthria (see Chapter 5); speakers who
have a paralyzed vocal fold (see Chapter 5); speakers who have nodules, a polyp, or
other mass on their vocal folds (see Chapters 3 and 9); speakers with a high spinal
cord injury (see Chapter 5); speakers with hearing loss (see Chapter 8); and geriatric
speakers (see Chapter 8).
6. Some voice-disordered patients will come to you because they have an imbalance
of oral and nasal resonance. Some examples include speakers with dysarthria (see
Chapter 5), speakers with cleft palate (see Chapter 10), and speakers with muscle
tension dysphonia (see Chapter 3).
GUIDED READING
Read the following articles:
Sapienza, C., Ruddy, B., & Baker, S. (2004). Laryngeal structure and function in the pedi-
atric larynx. Language, Speech, and Hearing Services in Schools, 35, 299–307.
Zraick, R., Gregg, B., & Whitehouse, E. (2006). Speech and voice characteristics of geriatric
Shapespeakers: A review of the literature and a call for research and training. Journal of
Medical Speech-Language Pathology, 14, 133–142.
Describe four ways in which the information reported in the articles might influence your
clinical practice.
PREPARING FOR THE PRAXIS
Directions: Please read the case study and answer the five questions that follow.
Harriet is a 75-year-old woman with a history of smoking one pack of cigarettes per day
for more than 50 years. Her chief voice complaints are rough voice quality, low speaking
pitch, weak voice, and running out of air when she speaks. She saw an otolaryngologist
(ENT), who diagnosed her with emphysema and Reinke’s edema.
1. The ENT’s report of his stroboscopic laryngeal exam noted “Reinke’s edema,
bilaterally.” Based on this information, which of the following laryngeal structures
were affected?
A. Superficial layer of the lamina propria
B. Intermediate layer of the lamina propria
74 The Voice and Voice Therapy
C. Deep layer of the lamina propria
D. The vocalis muscle
2. Which of the following laryngeal findings would also likely be noted by the ENT?
A. Vocal fold atrophy
B. Vocal fold paralysis
C. Vocal fold nodules
D. An hourglass glottal space when the vocal folds are adducted
3. Which of the patient’s following pulmonary function test values are abnormal?
A. Total lung capacity of 3,000 cc
B. Vital capacity of 2,900 cc
C. Expiratory reserve volume of 650 cc
D. Total lung capacity of 4,900 cc
4. Which of the following findings primarily accounts for the patient’s low speaking
pitch?
A. Increased mass of the vocal folds
B. Decreased mass of the vocal folds
C. Incomplete glottis closure
D. Irregular vibration
5. Which of these behavioral suggestions would be optimum for Harriet?
A. Smoking cessation and counseling in vocal hygiene
B. Total voice rest
C. Whisper
D. Aspirate glottal attack (onset)
CHAPTER 3
FUNCTIONAL VOICE
DISORDERS
LEARNING OUTCOMES
After reading this chapter, one should be able to:
●
Define the term functional voice disorders.
●
Describe excessive muscle tension disorders.
●
Describe benign pathologies associated with excessive muscle tension disorders.
●
Describe the voice symptoms of muscle tension disorders and their management.
●
Define the nature of psychogenic voice disorders and treatment options.
75