The yawn-sigh as a voice therapy
technique has had increased usage in recent
years, particularly with voice problems related
to vocal hyperfunction. The technique appears to
be especially effective in counteracting the
tension symptoms of elevated larynx and
constricied vocal tract that so often
characterize vocal hyperfunction (1).
Froeschels (2) in 1952 labeled the voice
produced with such excessive tensions as
-hyperfunctional dysphonia. Boone and McFarlane
(3) defined voice hyperfunction as the
involvement of too much muscle force and
physical effort in the systems of respiration,
phonation, and resonance. After summarizing some
of the early literature descriptions of vocal
hyperfunction, Brodnitz wrote that -natural
functions to overcome vocal constriction are the
sigh and the yawn- , both useful in overcoming,
the upward pull of the larynx. This present
study takes a critical look at the physiologic
characteristics and acoustic effects of the
yawn-sigh, and then offers suggestions for its
application in the treatment of voice disorders.
Simply put, vocal hyperfunction is using too
much force and effort while voicing. Instead of
using the term "vocal hyperfunction in his
writings, Aronson (5) described these same
behaviors and symptoms as a musculoskeletal
tension disordert hat is typically characterized
by an elevated hyoid bone and larynx. He further
wrote that "the extrinsic and intrinsic
laryngeal muscles are exquisitely sensitive to
emotional stress, and their hypercontraction is
the common denominator behind the dysphonia and
aphonia in virtually all psychogenic voice
disorders". He believes the primary treatment
for such musculoskeletal tension is maneuvering
the patient's laryngeal and hyoid anatomy to
promote greater vocal tract relaxation and to
lower the position of the larynx. These maneuver
procedures, which include gentle pressure and
massage (the procedures are well specified in
Aronson's writings), are similarly described and
urged as a primary treatment modality for vocal
hyperfunction by Prater and Swift (6).
The tense voice is often described in the
literature as a voice produced with poor breath
support, elevation of the hyoid bone and larynx,
mandibular restriction, unnecessary tongue
tension, and overall vocal tract constriction.
Part of such tract constriction was described by
Colton and Casper (7) as anterior-posterior
laryngeal squeezing where the "epiglottis and
the arytenoids approach each other during
phonation". Literature descriptions (3,6,8) of
tense vocal physiology are usually accompanied
by therapy techniques designed for reducing such
laryngeal and vocal tract tensions, such as
chant talk, chewing, glottal fry, initiating
phonation with the /h/ sound, the open mouth,
sighing, and the yawn-sigh. Each of these vocal
techniques are designed to open up the vocal
tract, permitting an easier phonation with a
minimum of muscular effort.
Much of the voice therapy program developed
by Boone and McFarlane (3) is designed to reduce
vocal hyperfunction, with the yawn-sigh often
used as a method for relaxing the vocal tract,
opening up the pharynx, and lowering the
larynx. Instead of using the massage
maneuver (5) to lower the larynx, Boone has
observed clinically that the yawn-sigh will not
only lower their larynx, but keep the larynx in
a low position while the patient continues using
the sigh mode of phonation. Among Boone and
McFarlane's 25 therapy-facilitating approaches
is the yawn-sigh, described as "a powerful voice
therapy technique for patients with vocal
hyperfunction. Procedures for using the
yawn-sigh are specified, which include an
explanation of what the technique can accomplish
for the tight voice, followed by direct
clinician modeling of the method. With the
explanation and the modeling, most (but not all)
children and adults with voice problems are able
to yawn and follow the yawn with a relaxed,
vocalized expiration (the sigh).
Pershall and Boone (9) developed clinical
concern that many of their voice patients had
such a squeezing of the larynx by hyperactivity
of the aryepiglottic folds that it was almost
impossible to view fiberoptically the vocal
folds below. As part of their study looking at
supraglottal constriction, they took a number of
computed tomography (CT) scans of the neck and
mandible of their research colleagues doing
various vocal tasks. In Fig. 1, we see the CT
scans of the same subject vocalizing EEH /i/
(Fig. 1a), the barker voice (similar to
belting), and in Fig. 1b, a sighed voice after a
yawn. The scans were taken at the level of the
third cervical vertebra, which placed the focus
of the scan just above the arytenoids. In Fig.
1, in each of the CT scans we identify the white
bone at the bottom of the picture as the third
cervical vertebra; the dark central area is the
open airway. The sighed -E- (/i/) produced the
most maximally dilated pharynx of all tasks
performed by all subjects. The CT scans
confirmed the flexible endoscopic observations
of Pershall and Boone, which showed that the
yawn-sigh produced marked pharyngeal widening
consistently across research subjects.
Clinically, it was observed that with the
descent of the larynx, the yawn usually opened
up the squeezed larynx.
Colton and Casper (7) have observed
fiberoptically that the larynx lowers
dramatically during a true vegetative yawn. They
report, however, that some patients have
difficulty initiating a yawn; they
speculate that this may be because people tend
to be socialized into hiding and stifling public
yawns. They do recommend, however, the natural
yawn as a way of eliminating abusive initiation
of phonation and for reducing laryngeal
tensions. In 1990, Casper et al. (10) reported
that no subject was able to produce the yawn
when the tongue was anchored down, which was
necessary in examining the patient with use of a
rigid endoscope; subsequently, similar to
Pershall and Boone, they have studied the
yawn-sigh using a flexible fiberoptic bundle.
They have found in those subjects who can
complete the procedure that the larynx descents
markedly and remains in the lowered position
during the initiation of the sigh (with a
gradual ascent back to the starting
position).
Boone has embraced the yawn-sigh as a
technique for relaxing the vocal tract, to be
used situationally by tense speakers. In his
self-help book (11) for voice self-improvement,
he introduces the invisible yawn-sigh as
a method for relaxing the vocal tract in public
situations (on the speaker's platform, at a
meeting, etc.). The patient keeps his mouth
closed and yawns; then he lets the air out with
a closed-mouth sigh (the air exits silently
through the nose). Even this modified yawn-sigh
appears to lower the larynx and dilate the
pharynx, producing a more relaxed vocal tract
and a more relaxed-sounding voice.
The yawn-sigh has had a host of clinical
advocates. Moncur and Brackett (12) encouraged
the use of the breathy yawn-sigh for treating
persons with "hypervalved larynxes and
hypertense muscles.Wilson (13) incorporated the
sigh with other therapy techniques for children
with hyperfunctional voice problems. Moore (14)
wrote that in reducing excessively tense
phonation, general relaxation procedures coupled
with a -vocalized sigh- will often produce a
relaxed phonation. The sigh is used by Greene
and Mathieson (15) in this manner, ie., after a
period of relaxed diaphragmatic breathing the
patient vocalizes on a deep sigh on the
expiratory airstream.
In this study we attempt to answer these two
questions: (a) What are the physiologic
mechanisms and the acoustic characteristics of
the yawn-sigh? (b) Why is the yawn-sigh a useful
therapy technique for reducing vocal
hyperfunction? [...]
DISCUSSION
A frequent undesirable vocal behavior in
vocal hyperfunction is elevation of the larynx
and constriction of the supraglottal airway.
Two commonly used therapy approaches for
reducing this vocal tract tension are the
maneuver-massage methods described by Aronson
(5) and the yawn-sigh as often described in the
voice therapy literature (3,7). Although both
approaches have the effect of lowering the
larynx, only the yawn-sigh has been demonstrated
(9,10) to also increase the horizontal
dimensions of the airway. For the seven subjects
in this study who could perform. the yawn-sigh,
each experienced a lowering of the larynx and
widening of the pharynx under the sigh
condition.
How does lowering the position of the
larynx influence the horizontal widening of the
pharynx ? Some understanding of the widening
mechanisrn of the pharynx was provided by Laver
(16) with his working model of hypo and
oropharyngeal physiology. He states that the
contraction and expansion of the pharynx is
heavily influenced by movements of the tongue
and larynx. During the production of the yawn,
the larynx descends by action of various
infralaryngeal muscles. The pharyngeal
constrictors relax. When the larynx is fixed by
the infrahyoid muscles, contraction of the
paired stylopharyngeus muscles widens the
pharynx laterally.
In this study, the larynx was observed to
remain in the descended position after the
yawn for the initial part of the sigh. As
the sigh continued, there appeared to be a
gradual ascent in most subjects. This laryngeal
lowering and pharyngeal widening appeared to
have a direct effect in lowering formants 2 and
3 of the seven subjects. The female subject who
could not yawn-sigh displayed no changes in her
formant frequencies. There appeared to be a
slight gap between the approximated vocal folds
in their total length under the sigh condition,
perhaps contributing to a perceived breathiness
with a resulting increased perturbation
level.
Does the same desirability for holding the
larynx in a lower position for singing hold for
the speaking vowe as well ? The vertical
positioning of the larynx has been found to vary
up to 30 mm above or below resting levels in
studying untrained singers producing extremes of
low to high pitches. The trained singer keeps
the larynx in a lowered position, regardless of
frequency or intensity demands, with only
minimal vertical excursion (17,18). With either
singing or speaking, laryngeal elevation
decreases vocal tract length (producing a
smaller pharyngeal resonating cavity for higher
frequencies), often compromises supraglottal
resonators, and increases the adductory force of
the vocal folds.
Perhaps for the normal speaker free of voice
problems, the vertical excursions of the larynx
accompanying upward and downward pitch
inflections are perfectly natural and should not
be discouraged. For the voice patient with a
problem. of vocal hyperfunction, however, there
may be dramatic gains from producing a more
relaxed voice with a lower-positioned larynx and
an open pharynx. Under these conditions, there
appears to be less "pressed" or "tight"
phonation. As observed in seven subjects in this
study, phonation appeared to be produced with a
slight glottal opening, the opposite of
excessive vocal fold compression.
It would appear that some patients with vocal
hyperfunction experience horizontal-vertical
pulling tensions of the larynx from many
sources: the anterior movements of the tongue,
the upward pull of the hyoid, the severe
compression of the thyroarytenoids within the
larynx, and the downward tug from infralaryngeal
muscles. In studying the intrinsic pitch of
vowels, Sapir (19) has developed a
horizontal-vertical pull hypothesis that details
how tongue movements contribute to
laryngealpharyngeal changes in both vertical and
horizontal dimensions. Excessive posturing and
movements of the speech articulators might well
contribute to pathological voice production.
Sapir writes: Treatment of laryngeal and
phonatory dysfunctions may therefore involve
reduction in articulatory muscle tension,
modification of supralaryngeal articulatory
posturing, reduction in vertical laryngeal
movements.
The yawn-sigh approach, when modeled first by
the clinician, can be performed by most patients
with relative ease. The lowering of the larynx
and the widening of the pharynx seem to
contribute to a more relaxed phonation,
characterized by a slight increase in
breathiness (usually the result of a lessening
of glottal tension), a slight elevation of
jitter, and a lowering of formants 2 and 3. The
selfanalysis of the speaker (and by his or lier
listeners) is usually that the voice produced on
the sigh feels and sounds relaxed.
It would appear that there are several ways
that the yawn-sigh can be employed in voice
therapy. An obvious way is to use the sighed
voice for the production of a relaxed voice. For
the patient with severe problems of vocal
hyperfunction, the sighed voice may be his or
her first attempt at producing feeling-hearing a
relaxed voice. The feeling and the sound of the
production should be reviewed by clinician and
patient. Another useful way of using the
yawn-sigh is to extend the sigh with
monosyllabic words beginning with /h/. The
patient is instructed to maintain the lowered
larynx and relaxed sound with a series of /h/
words with middle and back vowels. With a little
practice, phrases and sentences can be said on
the sigh. Patients can often monitor the lowered
laryngeal position by placing their fingers
gently on the thyroid cartilage. If laryngeal
elevation is felt, they are told to go back to
the sigh (which will lower the larynx) and then
continue. An extension of the method into
conversational voicing should produce only a
minimal elevation of the larynx, primarily on
high front vowels.
A more recent use of the yawn-sigh by this
author (11) is using the method situationally
with normal speakers who at times experience a
tense voice. In a tense situation, the
individual is told to produce an invisible or
"silent" yawn-sigh. This is produced by yawning
with one's mouth closed, followed by a
mouth-closed sigh. Only a slight nostril flaring
in some subjects is visible. The patient
benefits from the lowered larynx and dilated
pharynx produced by the sigh, usually producing
a relaxed phonation.
CONCLUSION
The yawn-sigh appears to be a useful voice
therapy technique for lowering the position of
the larynx, widening the supraglottal airway,
and producing a more relaxed voice. Under the
sigh condition (after the yawn), seven of eight
normal subjects lowered the larynx, retracted
and elevated the longue, experienced some
pharyngeal widening, and produced a more breathy
voice (with lowered formants 2 and 3). The
yawn-sigh is a useful technique for countering
tense supraglottal postures in patients with
vocal hyperfunction. Several applications of the
technique for use in voice therapy were
presented
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