The Valsalva Stuttering Network


by William D. Parry, J.D., M.A., CCC-SLP

  The Nature of Stuttering | The Valsalva Mechanism | The Valsalva Hypothesis | Stuttering Therapy | Electronic Devices | Stuttering Research | Valsalva Stuttering Therapy

The Nature of Stuttering

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 already has.

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.

Therefore, 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 articulate.  Conversely, 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 vowels.

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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 "hard onset").

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 Valsalva mechanism.

The 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.  The 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.” 

This 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 unconscious.

Based 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.

First, 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. 

The 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 lungs.

Meanwhile, 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 wall.”

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.”

The 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. 

This vocal 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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Stuttering Therapy

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 failed.

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 mechanism.

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Electronic Devices

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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Stuttering Research

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 non-pharmaceutical means. 

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 physiological core 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, thereby allowing fluency to follow on its own.

Individualized 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. 

Valsalva 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 the world.

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:


The 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


Not 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


Contact Information:

 William D. Parry, CCC-SLP
A licensed speech-language pathologist, offering Valsalva Stuttering Therapy and counseling by video conferencing over the Internet (subject to location and applicable law). 

Mail: P.O. Box 55, Merion Station, PA 19066-0055
Phone: 215-620-6792


Stuttering Therapy and Counseling:

The Valsalva-Stuttering Network:
Stuttering and the Law:

Valsalva Stuttering Therapy is a new approach to improving fluency by controlling the physiological mechanism that may be causing stuttering blocks. For further information on Valsalva Stuttering Therapy, visit Stuttering Therapy and Counseling at

The Revised and Expanded Third Edition of Understanding and Controlling Stuttering (2013) may be ordered from the National Stuttering Association or from

For information concerning stuttering self-help and support, please contact:

National Stuttering Association
1460 Broadway, New York, NY 10036
(800) 937-8888
Updated 5/28/2020

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Last revised: 4/9/16