Assessment and Treatment of Stuttering Using Altered Auditory Feedback

These findings highlight the need for many clients who stutter to use motor strategies to synergistically supplement or complement AAF. Initiation strategies such as vowel or voiced continuant elongation of the initial syllable, gentle onsets or even the production of a vocalic starting gesture appear to be good strategies when used in conjunction with AAF. Because breaks in the feedback after speech initiation might also be detrimental to the fluency-enhancing capacities of AAF, those with long, silent blockages might also require the use of motor strategies to help maintain continuous feedback. Kalinowski and Saltuklaroglu (2006) have recommended intermittent vowel prolongation to help maintain the feedback derived via AAF. However, these are but two examples of how motor strategies might be used synergistically with AAF to better enhance fluency. Currently there is no standard prescription for how these and similar strategies might be implemented concurrently with AAF to produce the best combination of fluency, natural-sounding speech and ease of use. However, the simple goal of this synergistic approach is the best possible emulation of CS. Of course, clinical testing of any such protocols are warranted, though it seems logical to suspect that ultimately, optimal combinations of AAF and motor strategies will vary based on their individual needs and expectations.

Demonstrated value

Reductions in stuttering frequency

A large body of data exists demonstrating that stuttering can be immediately and effectively reduced by 50–85% while reading under the effects of AAF. Though a number of studies have also found substantial decreases in stuttering in monologue and conversational tasks (e.g. Antipova et al., 2008; Stuart et al., 2006), the effects are generally not as robust as when reading and seem to be more variable across individuals (Lincoln et al., 2010). Lincoln et al. (2006) reviewed many of the studies examining changes in stuttering frequency under AAF, which may be considered Phase I clinical evidence according to the criteria outlined by Robey (2004). However, there is little evidence of efficacy data collected in more naturalistic extra-clinical settings. Pollard et al. (2009) recently attempted to address this need by measuring the effects of the SpeechEasy device on stuttering frequency in an ABA design using extra-clinical reading, monologue and a question-asking task. Though the authors reported no treatment effect after 4 months of use, their findings have been questioned based on their definition of stuttering, variable participant compliance to the protocol, under-sampling in the question task and the fact that their self-report data were considerably more positive (Saltuklaroglu et al., 2010). As such, there still appears to be a paucity of compelling data directly measuring changes in the stuttering frequencies under AAF in extra-clinical settings and there is a continuing need for research in this domain.

Reduced duration of stuttered events

AAF has also been found to reduce the duration of residual stuttering (Stuart et al., 2008), indicating an overall decrease in severity of remaining stuttered events. In other words, much like the presence of stuttering can contaminate the perceptually fluent utterances of those who stutter (Armson and Kalinowski, 1994), general increases in surrounding fluency can also impact perceptually stuttered speech, perhaps calling into question the manner in which we routinely measure stuttering.

Speech naturalness improvements

Improved speech naturalness is observed when those who stutter use AAF, presumably because of the increased fluency. In addition, it has also been found to be better when fluency is derived using AAF than when derived via fluency shaping, suggesting that the continuous use of motor strategies may impart an unnatural quality on speech (Stuart and Kalinowski, 2004). However, when motor strategies are only used intermittently with AAF, speech naturalness remains improved compared to NAF conditions, suggesting that intermittent use of motor strategies can be used without a detrimental effect on speech naturalness (Stuart et al., 2006).

Positive self-report data

Though there are few studies objectively measuring the effects of AAF in extra-clinical environments, self-report data, which captures the more experiential nature of stuttering and treatment efficacy, continues to suggest that AAF is effective in everyday communication. After using AAF presented with the SpeechEasy device for an average of 6.8 hours per day for 6 months, 105 users reported improvements in overall fluency in conversation and while using the telephone. Additionally they reported improved speech naturalness, decreased avoidances and strong overall satisfaction levels (Kalinowski et al., 2004).

Early work has begun (Cook and Smith, 2006; Molt, 2006; Runyan et al., 2006) investigating if use of the SpeechEasy promotes increased confidence and decreased anxiety and avoidance. If that proves to be the case, these added benefits might not be directly reflected in frequency counts of stuttered syllables. However, it is possible to speculate that they may have more of a positive global impact on speech naturalness, duration of stuttered events and the debilitative cognitive and emotional aspects of stuttering.

Advantages and disadvantages

Advantages

The primary and most attractive feature of AAF is the immediacy of its potent fluency-enhancing effects. Compared to other treatment methods, relatively stable, fluent and natural-sounding speech can be achieved in a shorter period, with a reduced role for extended therapy.

With the improved access to AAF systems, speech-language pathologists conducting stuttering assessments can immediately test the potential AAF has for reducing stuttering in almost any client. They can quickly examine how its effects work in isolation and often how best to synergistically combine AAF use with motor techniques for optimal fluency enhancement in a variety of speaking environments, including extra-clinical settings. Simultaneously, they can address clients’ immediate reactions to AAF, their perceptions of the resultant speech and help determine if AAF might be a suitable therapeutic option.

The benefits of AAF appear to extend beyond the realm of fluency, as evident by positive self-reports describing declining negative impact of the covert experiential aspects of stuttering such as avoidance and anxiety.

As suggested previously, AAF may best be used when combined with motor speech strategies. However, depending on individual needs, there are numerous possibilities for combining AAF, as either a primary or secondary therapeutic modality, with combinations of behavioural and cognitive therapies.

Disadvantages

Whereas the powerful effects of CS appear pervasive, it is clear that AAF does not reduce stuttering to the same robust extent in everyone who stutters. It is still unclear why this is the case and could be related to multiple factors including severity, individual patterns of stuttering, ability to initiate and maintain speech, age, ability to respond to an AAF signal, therapy history and possibly even different sub-types of stuttering (Antipova et al., 2008). Clearly more investigation is warranted to help evaluate the influence of these factors on fluency enhancement via AAF.

Because AAF offers the advantage of producing more immediate and natural-sounding speech than other methods, intervention periods may be shorter with a smaller role for the speech-language pathologist. As such, therapy with AAF often targets fluency alone. Consequently, little attention may be paid to the cognitive and emotional aspects of stuttering. Though self-report evidence suggest that improvements in these areas may be associated with AAF use, in general AAF focuses on decreasing overt stuttering behaviours rather than the covert experiential aspects, which if left unattended, might remain and continue to hinder communication. As such, it is recommended that speech-language pathologists using AAF educate clients regarding the possible need for additional therapy to cope with the covert emotional components of stuttering.

Questions arise whether long-term exposure to AAF may result in habituation to the signal, such that its fluency enhancement diminishes over time. Though Stuart et al. (2006) found that the positive effects of AAF did not diminish after 4 and 12 months post-treatment, their protocol included the use of motor strategies in conjunction with AAF. Still, as relapse after therapy is a common concern in treatments for stuttering, the possibility of habituation should be considered, especially if used without motor supplementation. However, it may be difficult to differentiate habituation effects from diminished attention to the signal and as such, attentional factors should be considered prior to making judgments about habitation. If diminishing effects are observed, they might be explained by current technologies failing to produce a continuously potent rendition of CS, rather than PWS not using a prescribed technique to enhance the effects. Future renditions of AAF are expected to provide more powerful and dynamic emulations of CS that would likely be more resistant to potential habituation effects. In current forms, frequent manipulations of DAF and FAF parameters, along with reminders to simultaneously implement motor strategies and attend to the signal, might be helpful for maintaining fluency gains over time.

Though many anecdotal reports exist of ‘carry-over’ fluency, such as continued improvements in fluency after AAF is removed, there is still little documented evidence that this might occur (Van Borsel et al., 2003). Thus, in order to maintain the effects of AAF, it appears that continued use of an external device to provide the signal is necessary.

Conclusions and future directions

The documented positive effects of AAF provide a strong impetus for continuing the evaluation of all its benefits in the remediation of stuttering. Measures should address changes across the entire stuttering syndrome, including naturalness, stuttering durations, and covert aspects of stuttering, along with stuttering frequencies. AAF should optimally be used in conjunction with motor strategies to complement and enhance the AAF signal, with the goal to emulate CS. Applied in this manner, the use of AAF can help provide effective and efficient fluency enhancement and serve as a strong catalyst for managing stuttering. Because of previous limitations in its method of delivery, its application in extra-clinical settings is relatively new and a great deal remains to be learned about the driving force behind the positive effects and how it can best be harnessed to best benefit clients who stutter across a multitude of speaking environments. Considering that technological advancements are forthcoming, it seems logical to conclude that the use of AAF in the treatment of stuttering is in its infancy and we should be optimistic about the potential treatment options it will provide in the future.

Continued research would be expected to provide a better understanding of interactions between speech and audition, their role in the nature and remediation of stuttering and factors contributing to the success or failure of AAF protocols in the management of stuttering.

Perhaps the most exciting prospect for AAF treatments is that improving technologies will surely lead to improvement in the electronic signal. In addition to improved second signals with fewer ambient noise problems, future versions of AAF may provide options for more dynamic signals and possibility of acoustic ‘gestural’ supplementation to silent periods to aid in speech initiation or when the second signal is halted by long silent blockages.

Discussion

Joseph Attanasio
Your presentation raised the question of how to combine such devices with more traditional treatment approaches. Can you expand on that?
Tim Saltuklaroglu
The methods I use (combinations of AAF and prolonged speech) have not been tested scientifically. I am using them intuitively and this is what I find works for me. The first thing I do is find out if AAF has the potential to help, so I will introduce a client to AAF in a gradual way by fitting the device, having them say some vowels, counting days of the week and months of the year gradually until they build up to reading passages. I get a feel for how much it is helping during reading. Based on the improvement I see during reading with the types of stuttering people are exhibiting, I introduce some intermittent prolongation. There are different ways I do that. Sometimes it is to put a prolonged vowel every third or fourth word. If that seems to help I’ll try to find an even balance. The idea is to introduce some prolongation to improve and maintain fluency and speech naturalness. If there are any particular hard sounds for clients I might instruct them to stretch the vowel just before that hard sound. Another strategy – and I like to us this myself1 – is to have clients stretch a few function words, such as ‘in’, ‘and’ and ‘on’. That is because, typically, with increasing age stuttering occurs less on function words compared to content words. Function words are short with strong vowels so I can do that without compromising naturalness too much. So that’s another intermittent prolongation strategy that I try for my clients and myself. Once clients are comfortable at a reading level using some type of vowel prolongation with comfortable fluency and natural-sounding speech, I will take them to the next level and try conversational tasks. Eventually I have them use the AAF device outside in the real world where they can see it works for them in a more natural setting and against some background noise. The process will vary with every client. I would not want to prescribe a ‘recipe’ for it. I think the important thing when using AAF is to understand how the signal works and how you can combine that clinically with prolongation in a flexible manner.
Sheena Reilly
Is there any evidence about the use of different types of AAF for conversational speech. We ask because the data that you presented to us is very much about reading tasks and it showed fine results there. But what sort of data exists for conversational speech? Also, our group were interested in whether people might be experiencing merely a placebo effect from using such devices?
Tim Saltuklaroglu
There has been less done with conversational speech than reading. However, recently The Australian Stuttering Research Centre group has reported on conversational speech (Lincoln et al., 2010) and there have been some other reports. The general finding is that fluency enhancement is not as strong as when reading and it varies from person to person. Some clients do quite well with conversation and others do not. I believe that is because of the difference in the tasks. During conversational speech there is the added demands of thinking, formulating and starting and stopping.2 I have seen clients who can do wonderfully with AAF during a reading task because all they do is focus on speech. But then during conversation these added demands make it a different task altogether. I think more research is needed to determine how to improve the effects of these devices in conversation.
Related to this issue is what the observers were asking me while your groups where meeting; see Preface for an explanation of who the observers were. How do we know it’s the acoustic signal or a speech signal? We’ve compared the effects of speech and non-speech signals (Dayalu et al., 2011; Kalinowski et al., 2000). With tones or even fricative speech sounds you don’t get much fluency. But things are different when you use a full speech signal. If you put a vocalic speech signal in, even if it’s not quite matched, you get a bigger improvement in fluency.
Sheena Reilly
If there are conversational treatment effects, whatever their nature and size, what do you think is the likelihood of long-term relapse with these devices?
Tim Saltuklaroglu
Surely a pressing issue. I would suspect that, just like any other treatment for stuttering, we would see some relapse. Perhaps it depends on whether clients need to attend to the signal constantly or whether any effects are a spontaneous adaptation to the AAF signal. Again, this issue requires research. Perhaps the configuration of frequency shift and delay parameters will influence long-term outcome.
Sheena Reilly
You seem not accepting of the Pollard et al. (2009) clinical trial incorporating everyday speech, which appeared to suggest overall that the device will not work for stuttering clients. Can you expand on those concerns?
Tim Saltuklaroglu
I had a problem with that study because of how they defined stuttering. They used a definition of stuttering that included things they taught in their protocol. Consequently, it was difficult to know what was stuttering and what was something they actually taught. Also, to test devices in the real world you need participants to be compliant. Many of the participants in that trial were not really using the device and some lost their devices.
Anne Packman
We were interested in the age range of clients for which you would recommend an AAF device such as SpeechEasy. There is a clip on YouTube of young children being fitted.3 What is your view about that?
Tim Saltuklaroglu
I have been asked about that a couple of times and I am always conservative with AAF and young children. The youngest child I ever fitted personally was 7 years old and I regret doing that. With that age there are issues with care for the device, being able to attend to the signal, and most importantly, using them in schools. Schools are noisy places and the background noise can be horrendous. I try now to not recommend them for anyone younger than 12 or 13 years. Some people do fit younger children, but I don’t. It makes inherent sense in some ways to fit young children because they do tend to respond quite well to AAF. And children generally do not have as many psychological issues as stuttering adults. Given the choice though, I would rather try some other treatment approaches first.
Anne Packman
The brain is more ‘plastic’ with children, so in theory our group considered that generalisation of any effects may occur better than for adults.
Tim Saltuklaroglu
I agree. And I think research may find easier ways to deliver the feedback for children in their everyday environments. Costs would of course be an issue. The SpeechEasy devices are currently $5000 in the United States and for any parent to send a child to school with this device poses some practical challenges.
Joseph Attanasio
You just mentioned cost. Would that be a potential confound for any clinical trials research. Clearly you place some stock in self-report clinical data. But if a client invests $5000 in a device, is that person about to admit it’s not working? Is it the opposite of buyer’s remorse? Do you have any information about why the clients make their self-report about the value of these devices?
Tim Saltuklaroglu
It would be difficult to separate out any of those effects. At Eastern Carolina University during the early years of testing, clients received their devices for a nominal cost. We did send a questionnaire survey of people who had bought the devices for full price. I think there is general bias if you ask clients how their treatment went, because they have invested much responsibility in making it work – but this applies to all therapies. So obviously, all this highlights the advantages of objective stuttering count data from blinded observers.
Sheena Reilly
How do you decide in what ear to put the device. Does it make a difference? And does it work differently? We discussed this a lot in relation to brain function.
Tim Saltuklaroglu
In relation to the brain it doesn’t matter, because auditory information from both ears goes to both sides of the brain. Assuming normal hearing in both ears, right-handed clients typically choose the right and hold the phone to the left ear so they can use the phone and receive AAF. Also, in terms of manual dexterity, if you are right handed it is easier to put the device in the right ear. If there is a hearing impairment in one ear, you need to work with an audiologist when fitting the device.
Anne Packman
Talking of the brain, we had a brief discussion about mirror neurons and I understand your theoretical support for the use of altered word feedback is that they engage mirror neurons. I believe there is some controversy these days about the actual existence of mirror neurons (de Zubicaray et al., 2010), so would you like to comment about that?
Tim Saltuklaroglu
Certainly, we could debate all day about the existence or lack thereof of a ‘mirror system’. For this reason I only alluded to the ‘possibility of the mirror system’ with a recent reference for its involvement in speech perception (Tremblay and Small, 2011). It is likely a semantic argument to some extent and not intended to be a topic of debate in the present forum. I believe the important message to convey is the link between speech perception and production is well established and it is possible that this link may play a role in aiding fluency in PWS.

References

Antipova, E. A., Purdy, S. C., Blakeley, M., & Williams, S. (2008) Effects of altered auditory feedback (AAF) on stuttering frequency during monologue speech production. Journal of Fluency Disorders, 33, 274–290.

Armson, J., & Kalinowski, J. (1994) Interpreting results of the fluent speech paradigm in stuttering research: difficulties in separating cause from effect. Journal of Speech and Hearing Research, 37, 69–82.

Chase, R. A., Sutton, S., & Rappin, I. (1961) Sensory feedback influences on motor performance. Journal of Auditory Research, 1, 212–213.

Cook, M. J., & Smith, L. M. (2006) Outcomes for adult males using the SpeechEasy® fluency device for one year. Poster presented at the annual convention of the American Speech-Language-Hearing Association, Miami, FL; November.

Dayalu, V. N., Guntupalli, V. K., Kalinowski, J., Stuart, A., Saltuklaroglu, T., & Rastatter, M. P. (2011) Effect of continuous speech and non-speech signals on stuttering frequency in adults who stutter. Logopedia Phoniatrics Vocology, 36(3), 121–127.

de Zubicaray, G., Postle, N., McMahon, K., Meredith, M., & Ashton, R. (2010) Mirror neurons, the representation of word meaning, and the foot of the third left frontal convolution. Brain and Language, 112, 77–84.

Fox, P. T., Ingham, R. J., Ingham, J. C., Hirsch, T. B., Downs, J. H., Martin, C., & Lancaster, J. L. (1996) A PET study of the neural systems of stuttering. Nature, 382, 158–161.

Goldiamond, I. (1965) Stuttering and fluency as manipulatable operant classes. In: L. Krasner & L. P. Ullmann (Eds.), Research in Behavior Modification. New York: Holt, Rinehart & Winston.

Hargrave, S., Kalinowski, J., Stuart, A., Armson, J., & Jones, K. (1994) Effect of frequency-altered feedback on stuttering frequency at normal and fast speech rates. Journal of Speech and Hearing Research, 37, 1313–1319.

Howell, P., El-Yaniv, N., & Powell, D. J. (1987) Factors affecting fluency in stutterers. In: H. F. M. Peters and W. Hulstijn (Eds.), Speech Motor Dynamics in Stuttering (pp. 361–369). New York: Springer Verlag.

Ingham, J. C., 1993, Current status of stuttering and behavior modification: Recent trends in the application of behavior modification in children and adults. Journal of Fluency Disorders, 18, 27–55.

Kalinowski, J., Dayalu, V. N., Stuart, A., Rastatter, M. P., & Rami, M. K. (2000) Stutter-free and stutter-filled speech signals and their role in stuttering amelioration for English speaking adults. Neuroscience Letters, 281, 198–200.

Kalinowski, J., Guntupalli, V. K., Stuart, A., & Saltuklaroglu, T. (2004) Self-reported efficacy of an ear-level prosthetic device that delivers altered auditory feedback for the management of stuttering. International Journal of Rehabilitation Research, 27, 167–170.

Kalinowski, J., & Saltuklaroglu, T. (2003) Choral speech: the amelioration of stuttering via imitation and the mirror neuronal system. Neuroscience and Biobehavioral Reviews, 27, 339–347.

Kalinowski, J., & Saltuklaroglu, T. (2006) Stuttering. San Diego: Plural Publishing.

Kalinowski, J., & Stuart, A. (1996) Stuttering amelioration at various auditory feedback delays and speech rates. European Journal of Disorders of Communication, 31, 259–269.

Lee, B. S. (1951) Artificial stutterer. Journal of Speech and Hearing Disorders, 16, 53–55

Lincoln, M., Onslow, M., Packman, A., & Jones, M. (2010) An experimental investigation of the effect of AAF on the conversational speech of adults who stutter. Journal of Speech, Language and Hearing Research, 53, 1122–1131.

Lincoln, M., Packman, A., & Onslow, M. (2006) Altered auditory feedback and the treatment of stuttering: A review. Journal of Fluency Disorders, 31, 71–79.

Lincoln, M., Packman, A., Onslow, M., & Jones, M. (2010) An experimental investigation of the effect of AAF on the conversational speech of adults who stutter. Journal of Speech, Language, and Hearing Research, 53, 1122–1131.

Max, L., Guenther, F. H., Gracco, V. L., Ghosh, S. S., & Wallace, M. E. (2004) Unstable or insufficiently activated internal models and feedback-biased motor control as sources of dysfluency: A theoretical model of stuttering. Contemporary Issues in Communication Science and Disorders, 31, 105–122.

Molt, L. (2006) SpeechEasy® AAF device long-term clinical trial: Attitudinal / Perceptual measures. Poster presented at the annual convention of the American Speech-Language-Hearing Association, Miami, FL; November.

Pollard, R., Ellis, J. B., Finan, D., & Ramig, P. R. (2009) Effects of the SpeechEasy on objective and perceived aspects of stuttering: a 6-month, phase I clinical trial in naturalistic environments. Journal of Speech, Language, and Hearing Research, 52, 516–533.

Robey, R. R. (2004) A five-phase model for clinical-outcome research. Journal of Communication Disorders, 37, 401–411.

Runyan, C. M., Runyan, S. E., & Hibbard, S. (2006). The SpeechEasy device: A three-year study. Poster presented at the annual convention of the American Speech-Language-Hearing Association, Miami, FL; November.

Saltuklaroglu, T., Kalinowski, J., Robbins, M., Crawcour, S., & Bowers, A. (2009) Comparisons of stuttering frequency during and after speech initiation in unaltered feedback, altered auditory feedback and choral speech conditions. International Journal of Language and Communication Disorders, 44, 1000–1017.

Saltuklaroglu, T., Kalinowski, J., & Stuart, A. (2010) Refutation of a therapeutic alternative? A reply to Pollard, Ellis, Finan, and Ramig. Journal of Speech, Language, and Hearing Research, 53, 908–911.

Stuart, A., Frazier, C. L., Kalinowski, J., & Vos, P. W. (2008) The effect of frequency altered feedback on stuttering duration and type. Journal of Speech, Language, and Hearing Research, 51, 889–897.

Stuart, A., & Kalinowski, J. (2004) The perception of speech naturalness of post-therapeutic and altered auditory feedback speech of adults with mild and severe stuttering. Folia Phoniatrica et Logopaedia, 56, 347–357.

Stuart, A., Kalinowski, J., Rastatter, M. P., & Lynch, K. (2002) Effect of delayed auditory feedback on normal speakers at two speech rates. The Journal of the Acoustical Society of America, 111, 2237–2241.

Stuart, A., Kalinowski, J., Saltuklaroglu, T., & Guntupalli, V. K. (2006) Investigations of the impact of altered auditory feedback in-the-ear devices on the speech of people who stutter: one-year follow-up. Disability and Rehabilitation, 28, 757–765.

Tremblay, P., & Small, S. L. (2011) On the context-dependent nature of the contribution of the ventral premotor cortex to speech perception. Neuroimage, 57, 1561–1571.

Van Borsel, J., Reunes, G., & Van den Bergh, N. (2003) Delayed auditory feedback in the treatment of stuttering: clients as consumers. International Journal of Language and Communication Disorders, 38, 119–129.

1 Dr Saltuklaroglu is a person who stutters.

2 Dr Saltuklaroglu is describing how conversational speech in effect requires dual tasking.

3 http://www.youtube.com/watch?v=Mdc2pT7zTas&feature=related

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