About the presenter: Anelise Junqueira Bohnen, PhD in Applied Linguistics (Federal University of Rio Grande do Sul, Brazil), investigating the characteristics of words stuttered by children and adults from 1986 to 2005. Master of Science in Speech Pathology and Audiology (Ithaca College, Ithaca, NY). Specialized in Fluency Disorders, was a participant in The Stuttering Foundation of America/Northwestern University workshops. Taught at three Universities for more than 10 years. Works with disorders of fluency since 1980 in private practice and is President of The Brazilian Fluency Institute - IBF.

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

A preliminary survey of vocal tract characteristics during stuttering: implications for therapy

by Anelise Junqueira Bohnen
from Brazil

The first idea of this preliminary study came from complaints of some people who stutter in my office back in 2005. These individuals had mild stutterings, but reported intense movement sensations in the vocal tract. Their stuttering frequency ranged from 5% to 8%. The duration of the stuttered words was below the average for the metropolitan area of Porto Alegre, RS. The values of this area are 1,10 seconds for stuttered word, with a confidence interval between 0,92 seconds and 1,27 seconds (Bohnen and Müller, 2002; Bohnen, 2005). And, what was intriguing was that therapeutic strategies either by stutter modification or fluency shaping programs were not producing acceptable fluency improvements.

Conture, McCall and Brewer (1977) and Freeman and Ushijima (1978) had published important articles about laryngeal muscle activities during stuttering. Since then, Douglas (2002), Sommer, et al (2002), Salmelin et al. 2000; Mulligan et al. 2001, Smith(1990), Dworkin et al. (2002); Foundas et al. (2001) and several others reviewed by Alm (2004), and by Maguire et al (2012), have been studying and reporting the multifactors involved in stuttering.

This preliminary study on the laryngeal characteristics of those who stutter reported here had two major goals: First, to verify if the general anatomical and/or physiological laryngeal characteristics reported in the literature, could be observed in the vocal tract of PWS through a flexible fiber optic laryngoscope evaluation. Second, to develop therapeutic processes and strategies that could improve each client's fluency after learning what happens in his/her vocal tract that is not observed by the naked eyes and ears.

Therefore, based on the assumption that the stuttered word is a manifestation of what happens in the brain and, consequently, in the vocal tract of those who stutter (Bohnen, 2009; Bohnen, 2011); that neuroimages are very expensive and almost inaccessible to research and diagnostic procedures in stuttering in Brazil; and that images captured through a flexible fiber optic laryngoscope are easily obtained, this diagnostic procedure was chosen as the one that could show movements at the same time they were produced at a very friendly cost.

This preliminary study was done through an examination of laryngeal movements of six adult males, with persistent stuttering, Brazilian Portuguese speakers, residents of the city of Porto Alegre, RS. The anatomical and physiological characteristics of the subjects' larynxes were observed during 90 seconds of spontaneous speech and reading of a text of 100 words. The text had some difficult and not very often used words in order to increase the chances of stuttering moments, once intermittence could play a role at the testing moment. The results were then analyzed by five judges: two laryngologists and three speech clinicians. The inclusion criteria of a particular movement in the list of results was that agreement among judges should be 100% about the presence of each specific movement understood as "different" from what was considered "normal" vocal tract activity (i.e. fluent activity).

In addition to healthy vocal folds and vocal tract of all 6 subjects, the images revealed 18 different laryngeal features, not usually seen in fluent speakers (Table 1).

Other movements were registered but did not meet the inclusion criteria. It was very apparent that out of the ordinary movements during stuttering occurred in a pre-phonatory state. Some say that converting an abstract thought into a concrete motor activity takes approximately 450 milliseconds (Sahin et al., 2009). In some of these subjects, initiating phonation took more than 3 seconds.

The increased activity of the intrinsic muscles of the larynx during stuttering detected in the images were different from those of the "normal" movement patterns expected for fluent speech. It is possible that the person who stutters, maybe in an attempt to prevent these odd movements, makes use of excessive muscle effort which, ultimately, further compromises his/her speech.

These observed movements were similar to those reported in the literature, such as: 1) excessive activity of the vocal folds musculature; 2) excessive activity in the supraglottic muscles, 3) prolonged muscle contraction, 4) long periods of pre-movement activation and 5) lack of synchrony between groups of abductors and adductors muscles of the vocal folds, consistent with the inferences of Freeman and Ushijima (1978), Conture, Schwartz and Brewer (1985) and Perkins (1986). It was also observed that the locus of occurrence of stuttered syllables was at the beginning and at end of phonation, which requires precision of vocal folds as a control valve to begin and finish the production of vowels.

Subjects reported feeling blocks and compression in the throat around the vocal folds' area which were not apparent to an external visual observation. After the laryngoscopy, their perceptions were confirmed by the obtained images. The increased level of laryngeal muscle activation in people who stutter may lead to an excessive increase in the brain's feedback system which, in turn, may increase the laryngeal motoneurons stimulation and, as a consequence, hyperactivating the feedback loop of phonation (Peters et al. 2000).

All subjects have given their written permission for showing these excerpts only for this paper.

In order to better understand what happens in the subjects' larynxes, http://www.youtube.com/watch?v=ACt8xh-wbm8 - the reader will see one example of intense activity of the vocal tract specially when there is no phonation. Most of the activity happens before the phonemes are produced and, although the spoken language is BP, it is easy to see when stuttering occurs. But it is not as easy to hear stuttering.

From 0:00 to 0:05 the intended phrase is /que é mais para diversão mesmo, né/ [which is more fun for yourself, really] in a translation where /more/ is the third spoken word. He says: /que é/, is not able to say /mais/, hesitates, goes back to /que é/ repeating the first words and then carrying out the whole phrase.

There are evident tremors in all structures when the attempted word is /mais/. The word "leitura" (reading) will appear at 0:09, signaling that the subject will begin the 100 word passage. It is easy to observe the struggle that happens before production of the first /u/ sound. It takes almost three seconds to initiate the word /uma/. Intense tremors are also easily observed. And tremors continue to happen up to the end of this video clip.

In the second example - http://www.youtube.com/watch?v=4vDJ6QxVDgI - between 0:03 and 0:06 there is an example of one movement never found in any other subject tested after the first 6 reported here. It is easier to see it than to describe it. This subject makes a reading mistake and when restarts the word with a different vowel, it is as if all structures were being pulled down in an inward motion.

The third case - http://www.youtube.com/watch?v=r9oYjMIWbLk - shows a curiosity. This client was speaking fluently most of the time after treatment. He was attending a fluency maintenance group. He insisted in participating in the evaluation because he was the learning English as a second language and, when reading in English he stuttered as much as when he first started therapy. And he was right. The reader can see what happens in this case. Unlike the previous subject, it is possible to see the laryngeal structures being pushed out.

Processes of language? Once he has to speak slower in a language he still had not mastered, why does stuttering manifest itself again, especially in reading situations?

The examination reported here allowed the observation of anatomic-physiological characteristics of the vocal tract during moments of stuttering. The movements observed in pre-phonation may indicate involvement of brain structures already observed in neuroimaging and reported in the literature. Although preliminary, the findings obtained are encouraging. Through a low cost examination it is possible to verify the functioning of the vocal tract of a PWS during moments of stuttering. A larger number of images are already being analyzed.

The second goal was to find a way to design therapeutic strategies that would allow a better synchronization of the movements of the laryngeal structures during stuttered speech. Once subjects were not responding satisfactorily to fluency shaping nor stuttering modification therapy programs, each client became part of the process of investigating which strategies and procedures would enhance fluency. For example: if the root of the tongue had a frequent up and inward activity, interrupting phonation, several motor exercises for this area were used or developed, including isometric exercises of resistance. Since the brain basically learns by repetition, and stuttering decreases in rhythmic conditions, motor exercises were always performed with a time unit of 4 seconds for each movement. This measure allowed planning and anticipation of the next movement in a specifically programmed time. Once groups of muscles learn to respond in a more organized and intentional form, the individual has a better way of using them whenever he anticipates a moment of stuttering.

As a speech clinician that deals with fluency disorders, one of my goals is to transform theoretical knowledge into practical applications so that the individual who stutters improves his/her fluency skills (Bohnen, 2007a; Bohnen, 2007b; Bohnen, 2009). The observations of this study are already allowing further investigations and improvements of therapeutic processes and strategies.


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You can post Questions/comments about the above paper to the author before October 22, 2012.

SUBMITTED: September 15, 2012
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