About the presenter: Peter Reitzes, MA, CCC-SLP is an ASHA certified speech-language pathologist working in an elementary school and in private practice in North Carolina. Mr. Reitzes is President and host of the StutterTalk.com podcast and author of 50 Great Activities for Children Who Stutter: Lessons, Insights, and Ideas for Therapy Success (PRO-ED).
About the presenter: Robert W. Quesal, PhD, CCC-SLP, professor in the Department of Communication Sciences and Disorders at Western Illinois University is a board-recognized specialist in fluency disorders, an ASHA Fellow. and recipient of his university's Provost's Award for Excellence in Scholarly Activity. Dr. Quesal is coauthor of OASES: The Overall Assessment of the Speaker's Experience of Stuttering, has published numerous articles and book chapters and presented workshops related to stuttering assessment and treatment.

You can post Questions/comments about the following paper to the author before October 22, 2011.

The Anatomy and Physiology of Costal Breathing and How it Relates to Stuttering

by Peter Reitzes and Robert Quesal
from North Carolina and Illinois, USA

This article is based on research and reporting conducted during 2011 for a four-part StutterTalk series on costal breathing available at http://stuttertalk.com/2011/02/27/costal-breathing-stuttering-series.asp

Costal breathing, sometimes referred to as diaphragmatic breathing, is a physical speaking strategy intended to prevent and manage stuttering. While costal breathing to treat stuttering has received little or no attention in peer reviewed journals and is largely unknown to speech-language pathologists in the United States, many people who stutter, especially in Europe, have attended costal breathing intensive programs or courses and report using the strategy with varying degrees of success and benefit.

Costal breathing will be described in detail below, but in brief, includes many or all of the following: the expectation and belief that the speaker can learn to voluntarily control different muscles in his or her diaphragm for speaking purposes; speaking at the top (the beginning) of breaths, taking noticeably full, big or deep breaths; taking quick, short breaths; taking shallow breaths; projecting one's voice; speaking with frequent pauses; speaking with a deep or low voice; speaking in an assertive manner; speaking using a breathy voice; attempting to push out all or most air before speaking and speaking "with no thinking pauses in the middle of a phrase that would stop movement of the diaphragm" (Johnston, 2007, p. 3). Some components of costal breathing may appear contradictory and abstract or vague; these points will be addressed later in the paper.

The two major programs which use costal breathing are the McGuire Program and the Starfish Project. Such programs also emphasize and focus on reducing avoidance behaviors, using desensitization practices such as voluntary stuttering, providing a supportive environment via peer counseling, encouraging positive attitudes about speaking and offering information about the disorder of stuttering. As a result, when costal breathing is discussed and taught, it is typically within a package or framework that includes other significant components and ingredients, which make it difficult to evaluate the physical costal breathing strategy in isolation from other aspects of treatment.

At present, the large majority of instructors and coaches teaching courses that use costal breathing are not licensed speech-language pathologists; they are people who stutter who have participated in such programs themselves and are offering treatment via organized peer counseling. It is important to note that while costal breathing is often taught via peer counseling, it is likely that this form of counseling closely resembles or, at times, is indistinguishable from a therapeutic relationship.

Many people who stutter report progress after attending courses that utilize costal breathing. This does not come as a surprise. It is clear that being in a supportive environment with other people who stutter is often associated with reduced negative feelings, increased self image, positive speaking and communication attitudes, success with speech therapy and other beneficial results (McClure & Tetnowski, in review; Yaruss, Quesal, Reeves, et al., 2002).

This review will focus on the costal breathing strategy to treat people who stutter and will not focus on other aspects of treatment such as avoidance reduction therapy and self help (peer counseling) which are typically used in conjunction with the physical speaking strategy.

Normal Breathing and Speech Breathing
Normal breathing (tidal breathing) is an unconscious activity. In fact, if one is told to "breathe normally," one usually is unable to do so because breathing has moved to a more conscious level. When we breathe for life purposes, inhalation is active and exhalation is passive; in other words, we use muscles to get air into the lungs but air is forced out by the natural recoil of the respiratory system. The primary muscle of life breathing is the diaphragm, but it important to note that this muscle is active during inhalation, but not exhalation.

Speech breathing is a more conscious activity than life breathing and requires more muscular effort. While inhalation and exhalation are roughly of equal duration during tidal breathing (about 40% of a respiratory cycle is spent inhaling, 60% exhaling), we need to get air in quickly and exhale it gradually for speech, resulting in about a 10%-90% inspiratory-expiratory ratio per cycle. The diaphragm and external intercostal muscles (located between the ribs) are typically active during speech inhalation and, initially, the external intercostals are active during the beginning of exhalation for speech as they "check" the nonmuscular forces from the lungs. After a certain point, the internal intercostal muscles activate and assist those passive forces and, depending on how much we have to say, other (accessory) muscles may come into play, particularly at lower lung volumes. However, the diaphragm is not active as an exhalatory muscle for speech. The reason for this difference in muscle activity in speech breathing vs. life breathing is that our goal during speech is to maintain a constant pressure (subglottal pressure) to drive the speech mechanism and maintain a steady voice. Although the diaphragm is said to contain two muscles or two portions - the crural and costal muscles (Pickering & Jones, 2002), it does not appear that these muscles or portions of the diaphragm can be activated or controlled independently (see quote from Pickering below). Readers can learn more about breathing and speech breathing from any basic speech science textbook (e.g., Hixon, Weismer, & Hoit, 2008; Raphael, Borden, & Harris, 2011).

Costal Breathing
Costal means relating to the ribs so costal breathing would suggest breathing using the ribs. It is often unclear, however, whether "costal" refers to the costal diaphragm or rib (costal) muscles. In an article titled "The McGuire Programme Unmasked," Geoff Johnston (2007), a regional director of the McGuire Program, explained some of the basic tenets of costal breathing. In the portion of the paper to follow, we will respond to a number of Johnston's (2007) arguments. Johnston's statements are quoted in italics followed by our (Reitzes & Quesal) responses. All subheadings in this Costal Breathing section such as "Push Out Residual Air" are quoted from Johnston's (2007) article. Also, please note that there are several typographical errors in Johnston's original article that have been corrected in the following quotes for ease of reading.

"Push Out Residual Air"
Johnston (2007): "Before we take the breath to speak we must ensure that all air has been expelled from our lungs. It is only by starting with empty lungs that the next breath will be fast and full ensuring the diaphragm moves down and up again in one smooth, continuous motion" (p. 2).

Reitzes & Quesal: There does not seem to be any evidence that this is true. This is an inefficient use of the respiratory system and makes breathing and therefore talking harder from a purely physiological standpoint. Breathing quickly, more quickly than normal, does not ensure smooth diaphragmatic movement, and even if it did, it would not ensure smooth speaking or speaking with little or reduced stuttering.

As it is physiologically impossible for a living person to have no air in his or her lungs, Johnston presumably meant that the speaker should push out as much air as possible before speaking. However, there is no evidence that doing so would reduce stuttering and it is possible that pushing out or expelling more air than normally required during speech may lead to an increase in stuttering behaviors. That is because there is a significant change in lung pressure when one fully expels the air from the lungs and beginning speech at this point is highly inefficient. As with many different aspects of costal breathing, it is possible that what may be useful is not the physical tool and physical directions themselves, but the fact that the speaker is paying conscious and close attention to his or her speech.

"Expand Ribs and Inhale - Fast Rib Expansion"
Johnston (2007): "Using the costal muscles between our ribs we expand our chest quickly creating a vacuum and allowing air to rush into our lungs. The breath must be fast to counteract the tendency to hold back" (p. 3).

Reitzes & Quesal: It is not clear what holding back means. It is very possible that other aspects of the program that focus on fear reduction and anti-avoidance may be reducing the tendency to hold back. It is not clear why a special technique must be used to allow air to "rush" into the lungs and, once again, this actually makes speech more effortful. During respiration, air already rushes into the lungs and we are aware of no evidence that people who stutter inhale air in a slower manner than non-stuttering individuals. It is also unclear how the fast breath works to "counteract the tendency to hold back."

"Full Rib Expansion"
Johnston (2007): "The in-breath must be full to build up air pressure behind the vocal cords so that they remain open to prevent blocking while speaking" (p. 3).

Reitzes & Quesal: Some, perhaps many, people who have used costal breathing understand taking a full breath to mean taking a deep breath. For example, in one of the only textbooks that discusses costal breathing to treat stuttering, Ward (2006) explains, "Before speaking it is important to take a deep costal breath" (p. 307).

Once again, it is important to emphasize how a deep breath affects speech breathing. There is a relationship between subglottal pressure (i.e., lung pressure or pressure beneath the vocal folds) and vocal fold resistance. When there is more air in the lungs, subglottal pressure is increased. The greater the subglottal pressure, the more the folds resist that pressure. Also, the more tightly you force your vocal folds together, the more air pressure you need to blow them apart. The reaction of the body to air pressure below the folds is to lock tightly, not to "remain open." We suggest that readers give it a try: take in different amounts of air and try to start talking at those different lung volumes. We are pretty sure that most will find that if you take too much air in your lungs, it becomes harder to get phonation started. The system works most effectively when the lungs contain between about 30-60% of the usable amount of air (known as vital capacity). When you go above and below that, atmospheric pressure and lung pressure are too different from each other and you have to work a lot harder. That is basic physiology. It is possible that this component of costal breathing is based on some sort of imagery, but its result is not improved speech efficiency. If costal breathing "works," it is difficult to see how it can be based on making the system work better.

It is also worth noting that while many describe costal breathing as requiring full or deep breaths, others describe costal breathing as "shallow breathing" (Tomer, 2009). Others have explained that costal breathing requires "short" and "quick" breaths. How exactly does one speak using short, quick, deep, full, shallow breaths? These are some of the contradictions in how costal breathing is described.

"Project Our Voice Through the Chest -- Perfect Timing"
Johnston (2007): "After taking the breath we must speak right at the top of the breath not a moment before or after. Timing is critical. . . ." (p. 3).

Reitzes & Quesal: It is unclear what it means to speak at the top of the breath, but one may assume it means at the beginning of exhalation. We are not aware that the majority of people who stutter do something different than begin speaking at the beginning of exhalation. Of course, it is common to get stuck in a stutter when beginning to speak which is why so many treatment programs and speech tools focus on "getting started." Again, this aspect of the tool may have more to do with paying attention to one's speech than with performing the tool in a specific manner.

"Assertive First Sound"
Johnston (2007): "The first sound of the first word must be quite assertive to make a strong start and to counteract the fear or tendency to hold back" (p. 3).

Reitzes & Quesal: The idea of assertive speech is abstract and may do more to motivate someone than actually provide physical speaking directions. It is unclear what is physically meant by giving the direction to speak assertively.

"Keep Moving Forward & Don't Hold Back"
Johnston (2007): "Once we begin to speak we need to keep moving forward until the end of the phrase with no thinking pauses in the middle of a phrase that would stop movement of the diaphragm and present an opportunity for a block" (p. 3).

Reitzes & Quesal: We are aware of no evidence that suggests "thinking pauses" lead to a stopping or halting of the diaphragm and to an increase in blocking or moments of stuttering. In fact, when listening to people use costal breathing it seems that some, perhaps many, are using pausing and rate control as part of the technique. Reducing the rate of speech in ways such as pausing is often associated with reduced moments of stuttering (see Reitzes, 2006).

"Deep and Breathy Tone"
Johnston (2007): "We project our voice through our chest with a deep and breathy tone that psychologically takes away the speech from the vocal cords and the articulators (tongue and teeth) where the blocks occur" (p. 3).

Reitzes & Quesal: We are unsure exactly what projecting one's voice through the chest means. Speaking with a breathy tone appears to contradict the previously quoted instruction to speak assertively. What does it mean to "psychologically take the speech away from the vocal cords and the articulators?" As with other aspects of costal breathing, this component of the tool is abstract and unclear and seems to have more to do with imagery or symbolism than physical speech movements. In a similar vein, one StutterTalk listener who participated in several intensive costal breathing courses observed that costal breathing seemed to be based on speaking with the diaphragm instead of the throat. How does one remove the throat from speaking? Again, this may have more to do with imagery and symbolism than physical speaking strategies.

What Are the Theories Supporting Costal Breathing as a Speaking Strategy?

Ward (2006) states that proponents of costal breathing believe it "works to bypass a compromised crural diaphragmatic system" (p. 309). Ward explains:

McGuire [the founder of the McGuire Program] argues that because the crural diaphragm controls airflow for normal speaking, it is therefore this which spasmodically contracts in response to feared situations amongst people who stutter. Thus, in order to control stuttering, one can either retrain the crural diaphragm or work on desensitization to the fear, both of which may take considerable lengths of time. Alternatively, one can train oneself to use costal breathing." (p. 307) Proponents and graduates of intensive programs that focus on costal breathing have reported that a significant part of the costal breathing treatment strategy includes training one's body to use the costal diaphragm more than the crural diaphragm. Dr. Mark Pickering, a researcher at the Conway Institute of Biomolecular and Biomedical Research at the University College Dublin, was asked for his professional opinion on costal breathing. He wrote: There are a few problems with the suggestion that people use the crural diaphragm for speech, and one can learn to use the costal diaphragm more. First, I don't think it is possible to voluntarily dissociate the motor control of the crural and costal diaphragm, i.e. you cannot decide to contract the crural diaphragm and leave the costal diaphragm relaxed. To go into more detail, the phrenic nerve that controls the crural and costal diaphragm has its origins in the brainstem, and the neurons going to both muscles seem to share the same excitatory inputs, effectively having a common "on switch," meaning you can only contract both muscles or none. However, there seems to be an additional inhibitory input which is specific to the crural neurons, meaning a selective "off switch" for the crural diaphragm. The result of this is that there are occasions when the costal diaphragm can contract without the crural diaphragm contracting. However, this only occurs at specific times, and usually related to digestive function, such as vomiting and swallowing, is not under voluntary control, and there are no instances I am aware of that it occurs the other way around under normal circumstances, with the crural diaphragm contracting more than the costal diaphragm. Therefore I would doubt that people can, much less do, use the crural diaphragm for speech.

Second, because of the anatomical differences between the crural and costal diaphragm, the main movement of air is driven by the costal diaphragm. When the crural diaphragm contracts, very little air is moved into the lungs. If it was possible to just use the crural diaphragm, I don't think enough air would move to create speech.

The third point is that, even if this were possible, I don't know how a person would know how much relative contraction of the crural and costal diaphragm was occurring, i.e. if you could do it, you wouldn't be aware you were doing it.

However, it is of course possible to voluntarily change the breathing pattern to increase use of the diaphragm as a whole. This seems to be a much more likely explanation (personal communication, February 10, 2011).

To summarize, the evidence indicates that although there are two parts to the diaphragm, they do not work independently for speech, nor can they be voluntarily controlled. Once again, we would suggest that the explanations for why costal breathing works do not hold up to scientific scrutiny.

Should Costal Breathing Work for Everyone?

In a message on a stuttering email group, David McGuire (1997), the founder of the McGuire Program, explained, "We [the McGuire Program] spend considerable effort in evaluating our results which show that 75% to 80% experience a significant (if not total) improvement and a profound life change which holds up and improves over time. The other 20 to 25%, for whatever reason, do not succeed simply because they stop trying." Ward (2006) noted:

Some graduates [of the McGuire Program] have reported that they felt they had failed because they had been unable to master the breathing technique. Some former students have said that they felt the ethos is that if the speaker follows the program's directives then he will become fluent. If he doesn't, then it is the fault of the speaker for not putting in the effort. (p. 309) Considering the lack of evidence and lack of efficacy data on the treatment of stuttering using costal breathing, it is curious that some would take the position that blame should be placed upon the client for not achieving fluency. Not a single peer reviewed study has ever been published on costal breathing. Until the costal breathing technique to treat stuttering is thoroughly researched and objective evidence is presented, it seems premature to suggest, state or imply that a person who stutters has failed because he or she has not tried hard enough using the tool. It is more probable that the tool itself is not effective for all or even most stutterers.

It is important to note that many researchers and therapists are coming to the conclusion that specific speech tools are responsible for relatively small aspects of change, and that the therapeutic alliance (the relationship between the client and clinician) and the hope that treatment will result in positive change are considered much stronger indicators of successful treatment (see Manning, 2009; Zebrowski & Arenas, in press). If anyone is going to suggest or make the claim that a specific speech tool should be effective for all, it is reasonable to ask -- Where is your evidence?

Conclusion and Suggestions

Anecdotal evidence suggests that treatment programs which incorporate costal breathing can be beneficial to some people who stutter. What is unclear is how significant the physical speaking strategy of costal breathing is in the process of change. How do we know the worth of costal breathing when the tool itself is not clearly defined and has not been studied in a rigorous, peer reviewed manner?

If costal breathing helps people manage stuttering, it is important that the tool is specifically and effectively defined so that people who stutter, instructors and coaches, speech-language pathologists and others know how to use it and teach it. In addition, as Ratner (2005) has pointed out, "Clinicians seem to have more of an affinity for programs whose mechanisms they understand" (p. 171).

The costal breathing speaking strategy contains several contradictions, and many of the physiological explanations of costal breathing reviewed in this paper are simply not logical and are not supported by evidence. While costal breathing is presented as a physical speaking strategy, it has, to date, been integrated with other aspects of treatment such as avoidance reduction and fostering positive attitudes. To know the worth of the physical costal breathing tool itself, much study needs to be done. For one example of the type of research we are suggesting, intensive programs could be set up and researched which offer avoidance reduction, peer support, self-esteem building and facing fears. Each subgroup within the program would receive different physical speaking strategies to use. For example, one group uses costal breathing, another uses stuttering modification tools, another uses fluency shaping tools and a fourth uses no physical speaking strategies at all. Ideally, costal breathing will be studied in such a manner so that the scientific use of control groups will help determine the efficacy of this physical speaking strategy.

It is important to note, of course, that many treatments for stuttering should undergo the same rigorous scrutiny and we are not suggesting that costal breathing is the only technique that is not supported by peer-reviewed data. There are clearly aspects of programs that utilize costal breathing that many people who stutter find useful, supportive and life changing. It is our hope that future research will illuminate what is working and why so that we better understand how to support and help people who stutter.

For more information, the British Stammering Association maintains a Costal Breathing page with numerous links and resources at http://www.stammering.org/adther_costal.html


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Reitzes, P. (2006). Pausing: Reducing the frequency of stuttering. Journal of Stuttering Therapy, Advocacy and Research, 1(2). Retrieved August 6, 2011 from http://www.journalofstuttering.com/1- 2/Reitzes.2006.JSTAR.1.64-78.pdf

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Yaruss, J.S., Quesal, R.W., Reeves, L., Molt, L.F., Kluetz, B., et al. (2002). Speech treatment and support group experiences of people who participate in the National Stuttering Association, Journal of Fluency Disorders, 27, 115-134.

Zebrowski, P. M. & Arenas, R.M. (in press). The "Iowa way revisited." Journal of Fluency Disorders.

You can post Questions/comments about the above paper to the authors before October 22, 2011.

SUBMITTED: September 2011
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