Delayed
Auditory Feedback, nicknamed DAF, is sometimes helpful for older children,
teens and adults who stutter. DAF is easily accessible now as a mobile app. So,
I think it’s important to talk about it. DAF is when a speaker does not hear
her own voice in real time, but instead, hears it after a teeny tiny delay.
Here’s a more scientific description:
“Briefly, when speech is fed back to
a speaker via earphones at 75 to 100 milliseconds delay (one tenth of a
second), the speaker will automatically (passively) slow their rate of utterance,
flatten their intonation, prolong their words and/or raise their speech volume
to cope with the competing signal…
“The alteration in speech prosody
will often inhibit the stuttering response. Unfortunately this does not
carry-over very well because the DAF is not paired to the stuttering
specifically but to the speech signal in general. It is therefore difficult to
maintain this new speech pattern without the DAF/echo-present…
“The effects of speaking in the
presence of your own delayed speech signal remains the single most efficient,
immediate and initially passive fluency evoking stimuli available.” A therapy
program may include DAF to help establish greater fluency, then arrange for it
to “be gradually reduced so that the individual is speaking with his own
internal controls.” [1]
Many of
my clients have tried DAF. In the late 1990s,
I helped several of them obtain free DAF for phone use. In 2001, I discovered
the Casa Futura School DAF in a catalogue and bought one. It cost almost $300 (and
another $27.00 when a student stepped on the headset). In 2008, I bought two more devices. It was the
most affordable DAF at the time. Then, in 2011, SPEECH4GOOD [2] put
DAF into a mobile application. One of my clients purchased it this spring for
under $10! Version 3.0 launched this month. These dramatic changes in price and
availability prompted me to re-examine the role of DAF for speech language
pathologists who treat stuttering.
My
own use of DAF has to do with the nature of my business. My clients tend not to follow through with the
rigorous expectations of speech therapy, so, I find myself writing fewer lesson
plans and more educational/problem-solving memos. That means spending a lot of time learning
about issues associated with fluency: concomitant disorders, therapy options,
parenting, child development, social communication, literacy, and the ever changing
landscape of public education. So, when new student responded particularly well
to DAF, I had another reason to re-examine this option.
Let’s begin with a study published this
year. It found that fluent adults
responded to DAF with an increase in stutter-like dysfluencies and sound errors,
and, the adults fell roughly into two groups. Adults who experienced the least
amount speech disruption with DAF were given the label “low responders.” The authors
of the study hypothesized that these low responders “have better developed
speech motor skills…[which enabled] fluent speech under the DAF perturbation by
using more accurate feedfoward control
[3]…[and
also] that low responders could be less dependent on auditory feedback…” The
other group of adults were greatly affected by DAF. This second group of adults experienced much
more speech disruption and so they were labeled “high responders”. “In
contrast, high responders have a high dependency on auditory feedback to
maintain fluency under typical speaking conditions…” In the larger scheme of
things, these results add “…to the accumulating findings that motor-phonetic
encoding involves auditory-to-motor integration.”[4] Perhaps
we can hypothesize that our clients respond differently to DAF because of
differences in auditory-to-motor integration. I propose that research such as
this justifies the inclusion of DAF as an option in speech therapy.
In truth, the use of DAF for persons
who stutter is a topic of contentious debate. I kind of enjoy heated arguments
in professional journals. I’m curious to read how deeply held disagreements are
thinly disguised as polite discussions. Also, controversy reveals fascinating
details. As I understand it, one side of this controversy over DAF declares that
decades of evidence prove DAF has a powerful effect on stuttering.[5] The
opposing view challenges this research.[6] The challenge is not trivial.
The issue of legitimacy appears in a
fascinating article about Lionel Logue, the speech therapist portrayed in The
King’s Speech.[7]
Highly respected clinicians of the early
20th century were unsuccessful in helping Prince Albert, Duke of
York, manage his stuttering. On the other hand, Lionel Logue, with less formal education,
was portrayed as experienced, persistent, and successful.
“Logue’s therapy methods were
typical of those used by other clinicians of his time…emphasizing diaphragmatic
breathing…muscle relaxation…methods that provided King Albert with a sense of
his own fluency [including] masking the feedback the king received from his own
voice, …singing through blocks…counseling…[and nurturing] the confidence that
he could, with hard work, within the proper therapeutic regimen, stutter less.”
[8]
“To achieve legitimacy, today’s
practitioners are encouraged to select methods that have been shown to be
efficacious when studied using evidence-based methods (ASHA 2011). For
therapies that have not been scrutinized by evidence-based systematic reviews,
today’s clinicians are sometimes asked to provide their own documentation of
therapy progress, using carefully controlled, objective methods…” [9]
By now, I’ve left DAF by the wayside and turned my attention to
Evidence Based Practice, commonly known as EBP. For any reader still with me, this
will be a short and productive digression. I cracked open a textbook to a
chapter about the role of evidence in stuttering treatment. Let’s begin with a definition. In EBP, “
evidence refers to research findings, and the goal of clinical practice is to
find and implement the treatment that represents the best combination of
information from three sources : (1) research (i.e., evidence), (2) physician
or clinician expertise, and (3) patient or client preferences.” [10]
I learned about four levels of
evidence quality and how, apparently, the only legitimate evidence in the field
of stuttering was provided by a few literature summaries, prepared by a few
authors, and justified only a few therapeutic approaches. I read about clinician
bias and insufficient client input. There appeared to be wholesale disregard
for whole lot of research. I like
reading my ASHA journals yet the article discredited such an approach,
stating “reading individual research reports should
actually be a last resort for practitioners.” [11] So, I respectfully disagree. Journal
publications provide more than experimental data. They include brief historical
reviews, theoretical hypotheses, and intriguing discussion. They illustrate ways
to think about complex issues.
Thankfully, this book chapter ended
with some suggestions. “For current stuttering treatments in particular,
because the highest levels of evidence hierarchy (systems, synopses, and even
multiple meta-analyses and systematic reviews) are not yet widely available, it
becomes the responsibility of the clinician to carefully assess the
effectiveness of the selected treatment with each client.” [12] EBP
can focus on “one clinician-client pair at a time” . Treatment should be
“directed toward relieving the client’s ‘source of complaint’” and “…the ‘most critical components of stuttering
treatment outcome evaluation…might be the self-judgments or self-measurements
made by the speakers themselves.’” We can apply this guidance to the use of DAF. [13]
Now that DAF is widely available as
an app, I feel that SLP’s should educate the public about how it might be
helpful. It could be a way for clients
to generalize communication goals outside the speech clinic. Apps may be a way
for clients to make the self-judgments and self-measurements necessary in a EBP
approach to communication change. I hope SLPs will take advantage of this
technology, even though it will require some creativity within the ideals of
EBP .
Epilogue:
I finished this article feeling
somewhat incompetent. Has my profession failed to keep up with recent changes in
health care standards? My mind cleared after
reading an article in the newspaper about the humanities in modern day higher education. College is becoming
a narrowly focused job training program rather than an opportunity for high
level, broad based education. “The tragedy of the humanities is that it has
become cordoned off: viewed as separate, arcane, and indulgent, instead of
something that undergirds the other parts of life. Maybe instead of trying to
steer students back to humanities degrees, we should be rethinking the way we
teach humanities in general. We could be foisting those thinking skills on
everyone, a bit.”[14] I could definitely relate! An SLP draws from a
wide range of knowledge and skills.
While I commend the profession of speech language pathology for staying grounded in science, speech/language therapy requires a generous amount of "humanness". Think about the personal manner of your child's pediatrician., or even the customer service you received while dining out? I feel the best of these relationships are based on something almost invisible yet tangible. The therapeutic alliance is similar for me - invisible yet essential. Which leads me to my next topic: mindfulness. But first, I'll visit an art museum and remind myself that life is more than big data.
[1] Richard M. Merson (2003)
“Auditory Sidetone and the Management of Stuttering: From Wollensak to
SpeechEasy” http://www.mnsu.edu/comdis/isad6/papers/merson6.html
[2] Speech4Good (broken link)
[3] Judith V. Butler (11/7/10) DIVA http://butlerspeechtherapy.blogspot.com/2010/11/diva.html,
italics mine
[4] H.C. Chon, et. al. (2013)
Individual Variability in Delayed Auditory Feedback Effects on Speech Fluency
and Rate in Normally Fluent Adults. Journal of Speech, Language, and Hearing
Research, Vol. 56, p. 500 for all quotes
[5] J. Kalinowski & V.K.
Guntupalli (2007) On the Importance of Scientific Rhetoric in Stuttering: A
Reply to Finn, Bothe, and Bramlett (2005), American Journal of Speech-Language
Pathology, Vol. 16, 69-76.
[6] P. Finn, et. al. (2005) Science
and Pseudoscience in Communication Disorders: Criteria and Applications,
American Journal of Speech-Language Pathology, Vol. 14, 172-186.
[7] Judith Felson Duchan (2012)
Historical and Cultural Influences on Establishing Professional Legitimacy: A Case
Example from Lionel Logue. American Journal of Speech Language Pathology, Vol.
21, 387-396.
[8] Ibid. p. 391
[9] Ibid. p. 393
[10] A.K. Bothe, et. al. (2010) The
Roles of Evidence and Other Information in Stuttering Treatment, in B. Guitar
& R.. MCCauley (eds.) Treatment of Stuttering: Established and Emerging
Interventions, (pp. 343-354).Baltimore, MD: Lippincott Williams & Wilkins. p.
344
[11] Ibid. p. 349
[12] Ibid. p. 352
[13] Ibid. remaining quotes from p.
351
[14] Joanna Weiss (June 16, 2013)
Humanities at Risk: Let’s rethink the way we teach college students. The Boston Sunday Globe, p.K8