Does speech therapy work?

I am writing a blog post, exceptionally, to respond specifically to a poster on @speech_woman’s list-serve who wrote to say that she is having a “career choice crisis” after 10 years of service. The poster is unsure whether she is making a difference because it is so hard to tell if each individual patient is improving due to her efforts or due to other events outside of her control (maturation, family and school inputs etc.). First I acknowledge this as a legitimate concern because in fact it is difficult for the speech-language pathologist to estimate in each case how much of an individual patient’s improvement can be attributed to the SLPs efforts specifically. Furthermore, I know that this particular crisis of faith is common among SLPs today. This summer I attended an excellent workshop on outcome measurement sponsored by Nancy Stonell-Thomas to launch the FOCUS (an excellent new functional outcome measure). One of the speakers (I’m sorry, I forget who it was) presented some outcome data collected at her rehabilitation centre. The SLPs were required to rate each patient’s progress toward their speech and language goals using goal attainment scaling and then use a check list to indicate the variables that, in the opinion of the SLP, accounted for the child’s successful or unsuccessful achievement of their goals. The fascinating result of this exercise was that the pie charts describing these explanatory variables were identical for both achievement of goals and failure to achieve goals: in both events, more than two-thirds of the pie-charts were associated with child and family factors as explanations for the child’s achievement or non-achievement of the goal. Most of the remaining factors were institutional, leaving the tiniest sliver associated with the SLP. In other words, SLPs did not believe that they had appreciable impact on the child’s rate of progress. It was the saddest conference presentation I have seen in 30 years. So there may be a lot of SLPs having a “career choice crisis” and it is not clear to me how these individuals get up in the morning and go to work. I think that a lot of the reason for this is that governments and employers have constrained the professional choices of the SLP so much that it may be possible that the SLPs in many institutions are not having a much of an impact which is sadder yet. Consider for example the Glowgoska et al. (2000) trial in which it was found that a community speech therapy service was no better than ‘watchful waiting’ – not a surprising result given that the service was rationed to six hours of contact per family over an entire year in the form of brief parent consultation sessions.

Notwithstanding the possibility that some SLPs are working in settings where the institutional constraints are so tight that the services may indeed be of little value, I want to demonstrate that SLP services, at least in the area of phonology/articulation, are very powerful. I will start in this post and continue with two more to be posted later this month. It pains me that that the poster to the list-service mentions 9 years of university education but seems unsure about the efficacy of speech therapy. It does not surprise me however because there are many text books that describe speech therapy procedures without saying a word about the research evidence that supports (or fails to support) to use of those procedures. Many people do not know for example that many quite good randomized control trials were conducted in the fifties and sixties and a whole host of well controlled single subject studies were published during the same period, laying down the empirical basis for our profession. It is important to have confidence in the efficacy of the treatment procedures that we employ in our clinical practice and ultimately, that confidence can only come from the published research literature in combination with the changes that we see in our patients from day to day. There are many ways to access summaries of this data. The Cochrane collaboration is the most well-known, and their meta-analysis of speech and language therapy (in a pediatric context) concludes that therapies for phonology and vocabulary are effective:

Law, J., Garrett, Z., & Nye, C. (2009). Speech and language therapy interventions for children with primary speech and language delay or disorder (Cochrane Review).  John Wiley & Sons, Ltd.

You can also follow @HealthEvidence and @speechBITE on twitter to receive news about the latest treatment efficacy studies. The SpeechBITE website has summaries of research efficacy studies in speech and language pathology.

When Françoise and I wrote Developmental Phonological Disorders: Foundations of Clinical Practice, we made a deliberate effort to support evidence based practice by (1) providing a literature review of the research evidence to support all the treatment procedures that we teach in the book; (2) with few exceptions, refusing to even discuss treatment procedures for which we could not find good quality supporting research evidence; and (3) providing information on how to measure treatment outcomes for each individual patient using both target specific and generalization probes.  We all know that evidence based practice involves integrating the best research evidence with your own clinical experience and the needs of the patient. The thing is – clinical experience should be objective just like research evidence – not just vague impressions about patient satisfaction – you really do need to measure the change in your patients at multiple levels. If you look at my previous post on CAS this is evident as the “session end” probes suggest that the children are making great gains each day but the “next day” probes indicate that in one of the treatment conditions the child is not retaining those apparent gains. When treatment is rationed to brief periods or infrequent contacts with patients, your impressions of change may not provide a true picture and therefore objective outcome measures become even more important.

So the short answer is, the research evidence absolutely shows that speech therapy works. Is it working with your patients? Only you can answer that by objectively measuring retention and transfer of what you are teaching. If you are using treatment procedures that have been validated by good quality research and the child is achieving your goals, you can conclude that you have made a difference in the life of that child.

In those environments where it seems that we are maybe not making a difference, speech-language pathologists need to take back our own profession. In Québec (where I am) the professional order spends all its energy fighting other professional orders. This is madness. The real battle is for the professional autonomy of the speech-language pathologist. We need to have the freedom to make decisions in the best interest of our patients. This is the fight that is worth fighting.

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Single Subject Randomization Design for CAS Intervention Research

I have recently returned from the very excellent Childhood Apraxia of Speech Symposium sponsored by the Childhood Apraxia of Speech Association of North America and held in Atlanta last month. The scientific presentations were wonderful and I hope to have posts related to many of them over the next few months. I begin by highlighting Larry Shriberg’s presentation as it relates to my current CASANA funded intervention study and I am, with some excitement, analyzing the data from the first cohort of participants this week since it is our winter break from teaching.

Dr. Shriberg presented data recently published in Clinical Linguistics and Phonetics (Shriberg, Lohmeier, Strand & Jakielski, 2012). In this paper the authors describe the use of the Syllable Repetition Task (SRT) for the identification of CAS. The paper, the test, and all the information you need for scoring and interpreting the test data is available for download at The Phonology Project website. The SRT consists of 18 items comprised of two to four syllables made up of the consonants /m, n, b, d/ and the vowel /ɑ/ and thus it is designed explicitly for children with speech delay. The task was administered to 4 quite large samples of children: Group 1, Typical Speech, Typical language; Group 2, Speech Delay, Typical Language; Group 3, Speech Delay, Language Impairment; and Group 4, CAS with this last group subdivided into idiopathic and neurogenetic etiological subtypes for some analyses. The test results were presented in the form of four scores: Competence, total percentage of correctly repeated consonants overall; Encoding Processes, percentage of within-class manner substitutions; Memorial Processes, ratio of sounds correct in 3-syllable-versus-2-syllable items; Transcoding processes, percentage of items containing one or more addition errors, subtracted from 100 for directional clarity. Most interestingly, the latter three scores were not correlated with each other within any of the groups although they were all moderately correlated with the competence score. The CAS group showed worse performance than the other three groups on all of these measures although their performance on the Transcoding processes measure was most distinctive. The diagnostic usefulness of the Transcoding score is much enhanced by also considering aspects of the children’s prosody in connected speech (inappropriate pauses, slow rate, lexical or phrasal stress errors). In conclusion, these findings were taken as evidence that CAS is a multiple domain disorder with low encoding scores reflecting incomplete or poorly formed phonological representations, low memorial scores reflecting difficulties with phonological memory, and low transcoding scores reflecting a motor planning/programming deficit. Given that the paper presents group data, and that the encoding, memorial and transcoding scores are not correlated with each other, it is not clear however that all children with CAS will show difficulties in all of these areas. It seems possible if not likely that there will be considerable heterogeneity within this population with different children showing variant profiles across these three speech processes. The purpose of our study is to consider this heterogeneity by examining response to three interventions in individual subjects.

In a previous post I mentioned an alternative to traditional single subject designs that does not require a stable baseline while allowing for statistical analysis. We are using one form of this design in this study, the single subject randomization design, more specifically set up as a randomized block experiment as described in my paper on the application of these designs to communication disorders research (Rvachew, 1988). We have six children participating in the study this winter and 3 more enrolled for the spring. I provide partial data for one child in this post simply as a way of demonstrating the usefulness of this design for research with low incidence disorders. The child is school age with borderline verbal and nonverbal IQ, speech delay, and ADHD. Apraxia of speech was confirmed by administration of the Kaufman Speech Praxis Test and maximum performance tasks revealing normal single syllable repetition rates but an inability to sequence three syllables consistently and at a normal rate. The results of the Syllable Repetition Task indicated an extremely low competence score despite encoding and memorial processing within the average range for his age. He did have difficulties with transcoding however as indicated by the characteristic addition of nasal consonants.

Three speech targets were selected for this boy: word internal codas, word-initial /l/ clusters, and word initial velar stops (with baseline performance in single word naming being 50, 29, and 33 percent correct respectively). All targets were addressed via pseudowords linked to nonsense referents in a functional context. All targets received 20 minutes of concentrated practice per week using the integral stimulation hierarchy as described by Christine Gildersleeve-Neuman. However, the prepractice condition (which was implemented for 20 minutes prior to the practice session) varied for each target. The three prepractice conditions being compared in this study were randomly assigned to the targets with the following result: word internal codas were treated using input oriented prepractice procedures, word-internal /l/ clusters were associated with sham prepractice procedures (control condition) and velar stops were treated with output oriented prepractice conditions. The input oriented prepractice conditions included auditory bombardment and error detection tasks as described by Rvachew and Brosseau-Lapre (see also Chapter 9 of our book, http://www.pluralpublishing.com/publication_dpd.htm). The output oriented procedures are described by Dodd and colleagues for improving the child’s ability to independently build a phonological plan for the word by linking syllables and phonemes to graphical cues and then chaining the subword units. Phonetic placement was also incorporated into this condition as needed.

Raw Session and Next Day Probe Scores for One Child By Treatment Condition

Raw Session and Next Day Probe Scores for One Child By Treatment Condition

In-keeping with the randomized block design, the child received three treatment sessions per week, with each treatment condition/treatment target pair assigned at random to one of the three days on a week by week basis. Two outcome measures were recorded: the child’s responses to imitative phrase probes that were administered at the end of the session to assess learning during a given intervention session, and the child’s responses to imitative phrase probes that were administered at the beginning of the next session to assess maintenance of learning. The child’s performance on these probes is shown on the figure below: pastel bars are the session probes indexing session performance and solid bars are the next day probes indexing maintenance of learning to the next session. Different colours represent different prepractice conditions. These probe scores were submitted to a nonparametric randomization test as described in Rvachew (1988) with the results indicating that there was no difference in probe performance at the end of each session as a function of prepractice condition, F(2,5) = 1.19, p = .392. However, there is a significant effect of prepractice condition when considering next day probe performance, F(2,5) = 23.01, p = .002. Now, I am going to make you crazy by not revealing which prepractice condition is associated with each colour! The reason is that this is just one child and I want to see the results for the other children –  I have observed the responses of the other children and have reason to believe that in fact there are differences in actual learning as a function of prepractice condition but we will feel more confident after having blinded transcriptions of probe data from more children. It should be obvious with this design that there are many other variables that can influence the outcome such as intrinsic differences in the difficulty of the targets, differences associated with the days of the week, and differences in clinician (although some of the same people were in the room during every session, the treating clinician was not the same during every session). Therefore we need to replicate the result many times before we feel confident interpreting these results. However, I wanted to introduce readers to the SRT, the notion of CAS as a multiple domain disorder, and the single subject randomization design as a way of looking at the relationship between response to intervention and underlying psycholinguistic profile. I hope that you will stay tuned – we hope to take data from the first six children to ASHA13.