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98 JCPSLP Volume 18, Number 2 2016 Journal of Clinical Practice in Speech-Language Pathology
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measurement: IV. Predictors of outcome for a behavioural
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Fluency Disorders, 23, 1–30.
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(2002). Epidemiology of stuttering in the community across
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Fader, E., & Haskell, P. (2015). Predicting treatment time
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(2006). Effectiveness of behavioral stuttering treatment: A
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Hoffmann, T., Bennett, S., & Del Mar, C. (2013).
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recover from stuttering – are gender (females being more
likely to recover), age of onset (the older age of onset, the
lower likelihood of recovery), time since stuttering onset (the
more time that has passed, the lower the likelihood of
recovery), and familial history of recovery. None of these
prognostic factors have been consistently reported to
predict an individual’s treatment outcomes. Instead
pre-treatment stuttering severity is the most consistent
predictor of successful stuttering treatment outcomes.
Individuals with milder stuttering have better treatment
outcomes. Stuttering severity has not been found to be a
consistent prognostic factor for whether or not an individual
continues to stutter or not.
There is unlikely a single factor that can reliably predict
treatment outcomes. Rather, it is likely that a combination
of factors – for example, combinations of stuttering severity
rate and relevant client factors (e.g., communication
attitudes, personality profiles) – will be more accurate in
predicting treatment outcome (Craig, 1998; Guitar, 1976).
To improve the strength of the evidence in prognosis
and predictive factors in stuttering, prospective studies are
needed with appropriate statistical methods for analysing
the data such as logistic regression analysis (Reed & Wu,
2013). The ideal study design for investigation of predictor
factors is the randomised control trial and the ability of a
factor to predict treatment outcome should be evaluated
per specific treatment (Adolfsson & Steineck, 2000).
To confirm that a factor gives prognostic as well as
treatment predictive information, a randomised study
stratified for the factor in question is needed. Also, for
each predictive marker, it is necessary to evaluate the
level of evidence as specified by evidence-based practice
models of hierarchy (Adolfsson & Steineck, 2000). As
the systematic review of randomised controlled trials is
considered to be the highest evidence available according
to models of evidence-based practice (e.g., Hoffmann et
al., 2013), it is recommended that systematic reviews are
conducted in the areas of prognostic and predictive factors
in stuttering.
The rigour expected for systematic reviews of treatment
efficacy studies with methods such as the Cochrane
Collaboration should be extended to studies of prognosis
and predictive factors of treatment outcomes in the future.
Systematic reviews of prognosis of health conditions are
becoming more recognised. The Cochrane Prognosis
Methods Group, established in 2004/5, aims to ensure the
best use of prognostic evidence in Cochrane reviews and
to conduct research to advance the methods of prognosis
reviews and other types of reviews, where similar methods
apply (The Cochrane Collaboration, 2015).
In the meantime, clinicians can continue to integrate the
available data on prognosis of stuttering and predictive
factors of treatment with their clinical judgment and
patients’ individual profiles to plan appropriate therapies.
Clinicians should strive to continuously evaluate therapies,
to establish therapeutic alliance and troubleshoot different
problems of response with their clients (Bloodstein &
Bernstein Ratner, 2008).
References
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Ambrose, N., & Yairi, E. (1999). Early childhood stuttering
I: Persistency and recovery rates. Journal of Speech,
Language and Hearing Research, 42 , 1097–1112.