The Nature of Stuttering |
The Valsalva Mechanism |
The Valsalva Hypothesis |
Stuttering Therapy |
Electronic Devices |
Stuttering Research |
Valsalva Stuttering Therapy
Nature of Stuttering
(sometimes called "stammering") is a specific
kind of disfluency, in which the flow of speech is involuntarily disrupted by
forceful closures of the mouth or larynx, by repetitions or prolongations of
sounds and syllables, or by hesitations or delays in making voiced sounds.
Stuttering generally involves an excessive amount of effort, force, and struggle
in the attempt to speak. It also may be accompanied by a variety of secondary
behaviors intended to avoid, postpone, or hide the blocks.
Stuttering is a complex and
multi-faceted condition which, depending on the individual, may involve a
combination of learned behavior and various neurological, physiological, and
psychological factors. Most people who stutter are able to speak fluently some of the time.
Therefore, it is usually not due to a lack of ability to speak, but
rather an interference with the speaking ability that the stutterer
Severity often varies, depending on
the speaking situation. Persons who stutter usually have no trouble
mouthing words silently, whispering, or singing. Some stutterers are
also fluent when speaking with an assumed accent or when acting out a role.
Persons who stutter often perceive
that an upcoming word contains a "brick wall" or "block" even before they try to
say it. This advance awareness indicates that stuttering blocks begin in
the brain - probably in the neurological motor programming for speech rather
than in the execution of the actual movements. Some people who stutter become adept at covert
stuttering, by substituting words and avoiding situations in which they fear
they will stutter.
Although many people who stutter
anticipate difficulty in saying words that start with certain
consonants, these sounds are not the real problem. For
example, a person repeating /p/ in “puh-puh-puh-Peter” or
prolonging the /s/ in “S-s-s-s-s-sam” or the /m/ in “M-m-m-mary”
is actually saying the /p/, the /s/, and the /m/ perfectly well.
Even when forcing on a consonant, the lips or tongue are in the
correct position. In each case, the real problem is the
speaker’s difficulty in producing the vowel sound that
follows. In words that begin with vowels, repetition or
forcing may occur on the glottal stop – a normally brief
closure of the larynx to build up and release air pressure to
accentuate the beginning of an initial vowel sound.
stuttering (stammering) is perhaps best understood and treated as
a specific kind of voice problem, rather than as a “fluency” problem or
an articulation problem.
Further evidence that stuttering is a
"voice problem" includes the fact that stuttering usually
does not occur when voicing is not required, such as when
silently mouthing words or whispering.
In such instances, the speech mechanism does not have to wait for
the larynx to be ready to voice the vowel sound, because phonation
is not involved, and therefore the lips and tongue are free to
stuttering almost never occurs while singing,
because the larynx is constantly prepared to phonate the
melody – which is carried on the vowel sounds.
Therefore, the lips and tongue are free to articulate, because
they don’t have to wait for the larynx to be ready to phonate the
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The Valsalva Mechanism
The Valsalva mechanism consists of
neurologically coordinated muscles in the mouth, larynx, chest, and abdomen.
It is designed to perform a Valsalva maneuver to increase air pressure
in the lungs by forcefully closing the upper airway while the chest and abdominal
muscles contract. This assists us in many types of physical effort and in
forcing things out of the body.
The ordinary Valsalva maneuver involves
tight closure of the vocal and vestibular folds of the larynx (called effort
closure) for the purpose of sealing off the respiratory tract, accompanied
by contraction of muscles of the abdomen and chest. The various elements
of the Valsalva mechanism appear to be linked neurologically so that they
tend to contract simultaneously. The force of the closure is in proportion
to the amount of pulmonary air pressure being resisted.
Ordinarily the Valsalva maneuver (with its accompanying effort closure of the
larynx) is done instinctively, without conscious thought. This occurs in
normal, healthy persons during lifting, pushing, pulling, defecation, natural
childbirth, and other strenuous tasks. (During activities such as lifting,
the rectal muscles also contract, to prevent accidental evacuation of the
bowels, but during defecation they do not.) However, a person can also either
perform a Valsalva maneuver on purpose, or consciously refrain from doing one.
The forceful closures associated with a Valsalva maneuver need not be limited
to the usual effort closure of the larynx, but may instead involve tight
closure of the lips or tongue, depending on which structure initiates blockage
of the airway. Consequently, forceful closure of the lips and tongue may
occur during the articulation of certain consonants, while forceful closure
of the larynx may occur during the initial articulation vowel sounds (known
as coup de glotte or "glottal attack" and sometimes referred to as
The Valsalva maneuver is also known to interfere with the playing of
trombones and other brass musical instruments.
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The Valsalva Hypothesis
Simply stated, the Valsalva Hypothesis
views stuttering as involving a neurological confusion between speech and the human body's
core of stuttering is the unreadiness of the larynx to voice
the vowel sound of a word or syllable. This occurs because the
larynx is neurologically prepared to participate in the exertion of
physical effort (by performing effort closure as part of a
Valsalva maneuver) rather than phonation.
neurological programming for effort attaches to the vowel sound –
probably because this is heart of the word or syllable and the part that
has the most energy.
Consequently, the speech
mechanism gets stuck on the consonant or glottal stop that precedes the
vowel – repeating, prolonging, or forcing on it – resulting in the various
behaviors called “stuttering.”
voice problem may be triggered and perpetuated by a variety of unhelpful
beliefs, expectations, and fears which have accumulated
through years of stuttering. Typical thoughts are: “Speech is difficult”;
“I always stutter in this situation, or on certain words or sounds”; and
“It will be terrible if I stutter.” Some of the triggers may be
on such underlying beliefs, expectations, and fears, the person who
stutters typically forms certain counter-productive intentions
when approaching speaking situations. The most common is: “It’s
important that I make a good impression by trying hard not to
stutter.” Accordingly, the person who stutters forms the intention to
use effort to control the outcome of his speech (e.g.,
making a “good impression” by not stuttering). Ironically, by using
of effort in attempting to control the outcome, the stutterer sabotages
the processes that actually need to occur in order to produce
speech. This almost always increases the likelihood of stuttering.
this intention causes his brain’s amygdalae to go on high alert to
detect upcoming words, sounds, or external cues that may be associated
with memories of past stuttering. When such a triggering stimulus
is encountered, the amygdalae send out signals that initiate a fear
reaction (also known as the fight-flight-freeze response) and the
release of stress hormones.
brain then prepares the larynx to close tightly to perform effort
closure as part of a Valsalva maneuver. This maneuver is a
natural bodily function designed to build up air pressure in the lungs to
stiffen the trunk of the body, so as to assist in the exertion of physical
effort or to ward off attacks by enemies. During effort closure, both the
vocal folds and the vestibular folds (which are located slightly
higher in the larynx) tightly squeeze together to block airflow from the
the abdominal muscles contract so as to push up the diaphragm and increase
air pressure in the lungs. The greater the air pressure, the more tightly
the vocal folds and vestibular folds squeeze to keep the air in. Even if
the larynx does not actually close, it is not neurologically
prepared to bring the vocal folds gently together for phonation of the
vowel sound. Consequently, there is a “vowel-phonation gap” in the
motor program for saying the word, which the speaker may perceive as a “brick
Because the larynx is not ready to voice the vowel sound, the speaker
hesitates, or his speech mechanism gets stuck on the consonant or
glottal stop that precedes the vowel – repeating, prolonging, or
forcing on it. Meanwhile, the stress hormones impair the speaker’s
rational thinking and create a strong urge to force out the word
quickly by using physical effort. The articulation of consonants may turn
into forceful closures by the lips or tongue to build up air pressure as
in a Valsalva maneuver. The harder the speaker tries to force out the
words, the tighter these closures become. These struggles to overcome
the vowel phonation gap are the behaviors called “stuttering.”
speaker may instinctively feel that using effort is the “right”
thing to do – perhaps the only thing to do. It may even help to
reduce his anxiety to some extent. However, the use of effort
continues to obstruct voicing of the vowel. The speaker’s attempt to
force out the word blocks the airflow needed to vibrate the vocal
folds and to produce sound, and it further prevents programming of the
larynx to phonate the vowel sound.
core of stuttering blocks” is
graphically illustrated by the following diagram (click here).
The Valsalva Hypothesis views the Valsalva mechanism as only one of many factors
involved in stuttering. For example, a stutterer's anticipation of difficulty might be affected, to varying degrees, by
attitudes, expectations, neurological impairments,
or emotional factors.
Furthermore, a child's original disfluencies may be caused by a variety of neurological,
psychological, or developmental factors not involving the Valsalva mechanism.
These original causes may be different for various individuals, but their
commonality is that they create the perception that speech is difficult and will
require extra physical effort. The child already accustomed to using the Valsalva maneuver
when exerting effort or expelling bowel movements may instinctively
assume that words can be forced out in the same way. Continuation of this
behavior during certain critical years of childhood may influence the
development of nerve pathways in the brain. Over time, these behaviors
become deeply rooted in the nerve pathways of the brain, making them extremely
difficult to change.
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At the present time there is still no reliable "cure" for
stuttering. Although many individuals benefit from various forms of speech
therapy, there is no therapy, device, or drug that is effective all the time
or for all people who stutter. Methods that appear to help some individuals
may not work for others.
Many "fluency" programs require the stutterer to abandon his or her
normal way of speaking or breathing (even when fluent) and to learn artificial
and unnatural speaking and breathing techniques that are supposed to prevent
stuttering. The fluency-enhancing effects of many speech therapies may be
attributed to their indirect effects on the Valsalva mechanism - mainly
due to a change of intention in speaking. For example, the
stutterer learns to focus his intention on achieving specific "targets" (such
as by utilizing light contacts in articulation, easy onset of vowel sounds,
emphasis on phonation, release of air prior to speaking, slow or stretched
speech, breathing techniques,
etc.), instead of trying to say the words. However, none of these programs
focuses directly on controlling the Valsalva mechanism itself.
Although such speaking techniques may temporarily produce a
kind of "fluent" speech, many patients complain that it sounds phony and
unnatural, lacks spontaneity, and takes too much mental concentration and/or
physical effort to maintain. As the stutterer tries harder to use the
techniques, he may tend to activate his Valsalva mechanism, thereby increasing
the likelihood of stuttering.
Typically a stutterer may attend an intensive "fluency
shaping" program, lasting as much as three weeks and costing thousands of
dollars. During the program, the stutterer learns a new speaking
technique, which may include various "targets" or "controls." At the end
of the program, he or she may emerge with a high degree of fluency. Then
comes the hardest part - trying to maintain that level of fluency by continuing
to practice the "targets" and "controls" in the real world. The initial
level of fluency is difficult to sustain and relapses are common. Follow-up
studies are sometimes conducted to determine how fluent the person remains after
several months or years. The original fluency often deteriorates over time
- sometimes quite rapidly - leaving the disappointed stutterer with no
understanding of why the technique temporarily worked or why it ultimately
Some therapies, such as "stuttering modification" programs, view
the blocks, repetitions, and other manifestations of stuttering as separate
learned behaviors, which the stutterer is encouraged to identify and to replace
with more fluent behaviors. The result is sometimes referred to as
"fluent stuttering." Again, the focus is primarily on the mouth and
larynx, with no attempt to identify or modify activity in the Valsalva mechanism.
Currently, speech-language pathologists are almost never taught about the
Valsalva mechanism and are generally unaware of its possible involvement in
stuttering. While therapists may encourage stutterers to relax the lips,
tongue, and larynx, these are only the tip of the iceberg. Control of the mouth
and larynx will be difficult as long as therapists ignore the physiological
mechanism providing the force behind the blocks.
"Stuttering management" programs try to teach stutterers to "manage" their
stuttering, rather than trying to become fluent. However, these programs do not include management of the Valsalva
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Throughout the years, a wide variety of "anti-stuttering" devices have
appeared on the market to alleviate stuttering. In recent decades they
have taken the form of sophisticated electronic gadgets. These have included
miniature electronic metronomes, such as the Pacemaster, worn like a
hearing aid; the Edinburgh Masker, which produces a noise that prevents
stutterers from hearing the sound of their voice; the Fluency Master,
which amplifies vocal vibrations; the Vocal Feedback Device, featuring an
electronic vibrator on the throat; miniaturized delayed auditory feedback (DAF)
devices, such as the SpeechEasy; and frequency altered feedback ("FAF")
devices, which cause stutterers to hear their voice at a different pitch
(including the SpeechEasy, which combines FAF with DAF).
As discussed at length in Understanding & Controlling Stuttering, the
fluency-enhancing effects of delayed auditory feedback (DAF) and
frequency altered feedback ("FAF") have been known in the laboratory for
many years, although the reasons are not thoroughly understood. The author
of Understanding & Controlling Stuttering suggests ways in which DAF and
FAF might promote fluency by affecting the "Valsalva-stuttering cycle."
Therefore, the principle behind the recently publicized SpeechEasy is not
new. What's new is the miniaturization of the device so it can be worn in
the ear canal. While many stutterers report benefits from the SpeechEasy
while wearing it, it is expensive, the results are not perfect, and background
noise often causes a problem.
None of these devices should be regarded as a "cure" for stuttering.
They only reduce stuttering while they are being worn, and their long-term
effectiveness has yet to be proved. Because they work by changing the way you
hear your own voice, you must begin talking before they kick in.
Therefore, they won't help you get through a silent block. You must you
start vocalizing first, for example, by beginning your speech with an "ahh"
sound. Furthermore, these devices do little or nothing to increase a your
understanding of stuttering or ability to control stuttering on your own.
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While no one doubts the importance of basic research on stuttering, there is
also a need for research to provide immediate relief for people who stutter.
Much of the current research is focused on new imaging techniques, such
as PET scans and fMRI scans, which produce colorful computer-generated pictures showing
differences in the way stutterers' brains function compared to non-stutterers.
This is exciting stuff, but we have yet to see anyone overcome stuttering simply by
looking at brain scans. Genetic research has shown that susceptibility to
stuttering may be inherited in many cases, but it's not likely that we will see
gene therapy for stuttering during our lifetime.
Other research has focused on pharmacological ways to reduce stuttering,
including various drugs that block dopamine receptors in the brain.
Recent clinical trials on pagoclone, an anti-anxiety drug that
acts as a gamma amino butyric acid (GABA) selective receptor modulator,
did not produce results that met the drug company's criteria for success. Although such drugs seem to produce a modest reduction in stuttering, the
question remains whether taking drugs is worth the long-term risk of side
effects, if an equal or greater increase in fluency might be achieved by
Meanwhile, stuttering research has almost completely ignored the possible
involvement of the Valsalva mechanism in stuttering behavior - which, if
properly understood, could bring immediate, practical benefits to many people
who stutter, for no additional cost and with no harmful side effects.
While the Valsalva mechanism is well known to medical science and even
trombone players, it is rare to find it mentioned anywhere in the speech
pathology literature. Consequently, information about the Valsalva mechanism is
not conveyed to speech therapists or to their clients.
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Valsalva Stuttering Therapy
Valsalva Stuttering Therapy
is a comprehensive new approach for treating the most
common form of stuttering, often referred to as “persistent developmental
stuttering.” Valsalva Stuttering Therapy is based on the realization that
most stuttering is caused not by a lack of ability to speak, but
rather by an interference with that ability.
Valsalva Stuttering Therapy addresses the neurological and
of stuttering blocks - the brain's substitution of motor programs for
effort instead of phonation of vowel sounds, in
response to anxiety or the anticipation of difficulty in speaking.
By understanding this "voice problem,"
Valsalva Stuttering Therapy is able to address more effectively the physiological, neurological, and
psychological aspects of stuttering, teaching effective new ways to
dissolve stuttering blocks and to reduce their occurrence. Rather than
focusing on controlling one's speech, Valsalva Stuttering Therapy promotes
easy, natural speech by relaxing the Valsalva mechanism, reducing the
urge to exert effort, and promoting the voicing of vowel sounds, so as to free the person’s own natural speaking
ability. This therapy intentionally does not emphasize fluency
per se, because efforts to “stop stuttering” would tend to activate
the Valsalva mechanism and be self-defeating. Natural fluency cannot be
forced. Instead, the goal is to free you to speak in an easy, effortless,
and natural way,
allowing fluency to follow on its own.
counseling also helps you transfer Valsalva-relaxed speech
to everyday speaking situations. The time required to obtain optimal
results will vary depending on the individual. However, the insights and
skills learned from Valsalva Stuttering Therapy may enable you to achieve
further progress on your own, while reducing the possibility of relapse.
Stuttering Therapy, in its current form, has been developed through actual
clinical experience, experimentation, and practice-based evidence,
involving the participation of more than one hundred persons who stutter from all over
For a more detailed description of this therapy and its
cost, see the
Worldwide Valsalva Stuttering Therapy Program,
also on this website.
Valsalva Stuttering Therapy should be seriously considered as an approach
to stuttering therapy because it is:
only approach that directly addresses the Valsalva mechanism's
involvement in stuttering behavior;
Comprehensive in that it addresses the psychological, neurological, and
physiological aspects of stuttering;
Consistent with natural-sounding speech;
Harmless, non-invasive, and without adverse side effects; and
dependent on drugs or devices.
The Valsalva Hypothesis and Valsalva Stuttering Therapy can radically change the way in
which we view stuttering. See
A New Outlook on Stuttering,
also on this website.
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Copyright © 2014 by William D. Parry