Thinking about ‘Dose’ and SLP Practice: Part III

Continuing my discussion about the concept of ‘dose’ as applied to speech therapy, I finally get to the heart of the matter which is the issue of the optimal ‘dose’ of speech therapy to achieve the desired outcome which in our context is generalization of a phonology goal to untreated words. In previous blogs I discussed the definition of ‘dose’ in terms of the number of effective teaching episodes and the need to identify the effective ingredients of your intervention beyond the therapeutic alliance. Here I will discuss ‘dose’ specifically, as in how many effective teaching episodes are enough to achieve a good outcome in phonology intervention?

Let’s begin by returning to the pharmacology context from which the concept of dosage is borrowed. How is the concept helpful to physicians? First, it is important to know the optimum dose (or dose range) for average patients so as to avoid harming the patient. If the prescribed dose is too low the patient may not improve and the continuance or worsening of symptoms and disease will be harmful for the patient. If the dose is too high the medication itself may be toxic and harm the patient directly. Second, the patient’s response to the medication is diagnostic. If the maximum safe dosage has been prescribed and the patient is not responding favorably the physician must seek the reason: Is the patient complying with the prescribed treatment regimen? Is the patient doing something else that interferes with the effectiveness of the medication? Is the health care system administering the dose as prescribed? Does this patient respond to medications in an individualized fashion, such that a switch to another medication is required? Is the diagnosis wrong such that an entirely different treatment is called for? I will describe the research on appropriate dose in the case of meaningful minimal pairs therapy (applied to preschool aged children with moderate or severe phonological disorders) and we can consider whether these questions are relevant in the speech therapy context.

The method of meaningful minimal pairs is a uniquely linguistic approach to therapy that has the goal of changing the child’s production of an entire sound class. The procedure has two key components: (1) teaching the child pairs of words that differ by a single phoneme; and (2) arranging the environment so that the child experiences a communication breakdown if both words in a  pair are produced as a homophone. (SLPs and researchers usually get the first part right but often forget the second!) The method is directed at the child’s phonological knowledge and therefore should not be applied until after phonetic knowledge of the contrasting phonemes in the perceptual and articulatory realms has been established.

There is a lot of research involving this method and at least two papers have carefully documented the dose that leads to generalization from trained to untrained words/targets. More than 50% generalization is the outcome of interest because we know from other studies that you can discontinue direct treatment on the target pattern at this point and the child will continue to make spontaneous gains. The two papers that I will discuss have the further benefit of allowing the reader to count the “dose” precisely as the number of practice trials. The papers also provide information about the number of sessions and the number of minimal pairs over which the practice trials were distributed.

Weiner (1981) demonstrated that the method was effective with two children, using a multiple baseline design and treating deletion of final consonants (DFC), stopping of fricatives (ST) and fronting (F). Four minimal pairs were taught per target pattern and use of the pattern was probed continuously for treatment words and on a session-by-session basis for generalization words. The results do not show that much difference across target patterns but the response across children was markedly different with one child showing much faster progress than the other for all targets. For example, Child A reduced DFC to below 50% in treated words after 120 practice trials and in generalization words after 300 trials. On the other hand, Child B required 200 and 480 trials respectively to reach the same milestones for DFC. Furthermore Child A was able to accomplish many more trials in a session (e.g., 400 practice trials over 5 sessions for child A or 80 trials/session vs. 570 practice trials over 13 sessions or 43 trials/ session for child B). Despite this large variance in rate of progress across children, the study suggests that an SLP should expect a good treatment response with this method after no more than 500 trials.

This finding was replicated in a larger sample (n = 19) by Elbert, Powell and Swartzlander (1991). In this study a behaviorist approach was taken to the treatment of the minimal pair words in contrast to Weiner’s procedure that emphasized the communication breakdown as an important part of the procedure. The children were taught one pair at a time in series and the study was structured to determine how many children would achieve generalization to untreated words ,at a level of at least 50%, after learning 3, 5 or 10 pairs of words. They found that 59% of the children generalized after learning 3 pairs which took an average of 487 practice trials (range 180 to 1041) administered over approximately 5 20-minute treatment sessions; 21% of children needed to learn 5 word pairs (1221 practice trials on average) and 14% needed to learn 10 words pairs (2029 practice trials on average) before generalization occurred. This left 7% of children who did not generalize at all.

How can we use these data about dosage in our treatment planning? There is a lot of useful information here. First, we know that it is possible to achieve 80-100 practice trials in 20 minutes. Therefore, if your treatment sessions are 20 minutes long you can target one phonological pattern and if they are 60 minutes long you can target 3. Second, they show us that children do not usually generalize in under 180 practice trials (and I would argue that the data indicate that it is number of practice trials rather than sessions that is important). What harm might arise if you provide a child with the government mandated 6 annual treatment sessions, targeting three patterns, but failing to achieve more than 100 practice trials for each target pattern across the 6 sessions? We can predict that the child will not start to generalize before the end of the block and therefore will not continue to make spontaneous gains after treatment stops. When the next block begins the child may be discouraged and less cooperative with the next SLP. The parent may become discouraged and seek out complementary or alternative interventions that are even more useless or harmful than speech therapy provided with insufficient intensity!

What if the child has achieved more than 500 practice trials and has not generalized? At this point you have more than enough reason to reassess your diagnosis and/or your approach. Child B in Weiner’s study for example did finally achieve many practice trials but did so slowly because he was unable to achieve the recommended intensity, producing much fewer than 80 practice trials per session. This child also failed to generalization after 500 trials for one of his targets. Perhaps this child was lacking in the necessary prerequisites such as stable perceptual and articulatory representations for the target phonemes. Or, perhaps the child viewed the communication breakdowns to be the SLP’s listening problem rather than his own speech problem and thus a disconnect at the level of the therapeutic alliance was hampering the child’s learning.  What about the children in Elbert et al who did not generalize at all? It was eventually revealed in the paper that these children presented with many “soft signs” indicative of both speech and oral motor apraxia. Therefore, continuing to almost 3000 practice trials for these children was most assuredly harmful, given that they were not benefiting from the approach and they were deprived of the opportunity to experience a treatment approach better suited to their needs.

I am hoping that this example in the specific context of minimal pairs intervention demonstrates that the concept of dosage can be very useful in speech therapy. We need much more research that establishes typical ranges of ‘dose’ for optimum outcomes for any given intervention procedure that we use. Then we need to track these dosages as we apply procedures in our interventions. It is important to remember that the dose is not the number of sessions or visits by the child or family to the SLP. Rather, the dose is number of learning opportunities experienced by the child. When the child is not learning and we know the child has experienced the optimum dose of practice trials, we can adjust our intervention procedures with greater confidence. We can also set evidence based goals for our clients and document objectively their progress with respect to these expectations. In addition to these benefits for individual clients, this kind of information will allow us to evaluate the efficacy of our service at the program level with an objectivity that is currently lacking. Imagine if a government or an insurance company suggested that they save money by reducing the dose of our medications below effective levels! We should not allow this solution to be proposed to reduce the cost of speech therapy services. The only way to protect ourselves and our clients is with more research and greater specificity about how our treatments work. We must know the right dosage.

Thinking About ‘Dose’ and SLP Practice: Part II

I have been talking about whether it is helpful to think about dose-response relationships as an important aspect of treatment efficacy. During a recent @wespeechies exchange, we discussed whether this “medical” concept should be applied to speech therapy. One objection raised was the idea that treatment efficacy is “all about relationships” and therefore the dosage of specific inputs was not all that relevant to outcomes. In psychotherapy, objections to manualized care protocols that prescribe specific procedures for defined cases are also based on the notion that treatment efficacy is determined not by the specific ingredients of the treatment program but rather by common factors, as I discussed in a previous blog. One of the important common factors is the therapeutic alliance. How important is the therapeutic alliance to treatment outcomes? And does attention to the therapeutic alliance preclude thinking carefully about which procedures to use in which amounts with a given case?

In psychotherapy the therapeutic alliance is defined “as agreement on the goals and tasks of therapy in the context of a positive affective bond between patient and therapist.” Even when working with children, this can be an important aspect of the treatment program. For example, McCormack, McLeod, McAllister and Harrison describe children’s experience of speech impairment in a paper entitled “My Speech Problem, Your Listening Problem, My Frustration…”. This qualitative study illuminates multiple facets of an SSD and further shows that the child’s perspective and the adult’s perspective on the problem and the solution are often not aligned. Shifting the child’s attention to the role of his or her speech problem in communication breakdowns will require a genuine, caring, sensitive and trusting relationship between SLP and child. Establishing common goals and motivating the child to try new tasks to achieve those goals will also be highly dependent upon the therapeutic alliance between child and therapist.

To understand how the therapeutic alliance impacts on therapy outcomes we must return to the psychotherapy literature because I am aware of no scientific studies in the speech therapy arena that have addressed this issue directly. In mental health services, the strength of the therapeutic alliance is measured by asking clients questions about their relationship with their therapist in three domains, specifically goals (e.g., We agree on what is important for me to work on.), tasks (e.g., I agree the way we are working on my problem is correct), and bond (e.g., I believe my therapist likes me).  Very large sample studies have shown that the relationship between therapist and client accounts for about 20% of variance in outcomes. However, the relationship between outcomes and the therapeutic relationship is reciprocal: if the client gets better, they have more trust in the therapist’s guidance regarding goals and tasks. Therefore, the therapeutic relationship is theoretically independent of the techniques and procedures that the therapist uses, but in practice these variables may be related.

To put this in the speech therapy context again, Francoise Brosseau-Lapré and I are in the process of publishing the results of our RCT, Essai Clinique sur les Interventions Phonologique. We found that an input oriented approach (procedures focused on perceptual and phonological knowledge with very little articulatory practice) was as effective as an output oriented approach (all procedures focused on articulation practice) for improving children’s articulation accuracy.  Therefore, when working with a very shy child who does not like to imitate or indeed, talk at all, during speech therapy, you and the parent and the child might all agree that the input oriented approach is the ideal way to work on the child’s speech problem. Initially the therapeutic alliance might be high but what if the implementation of the approach is not competent? We find for example that it is actually quite difficult to teach students to implement the procedures (focused stimulation, error detection tasks and meaningful minimal pairs procedures) correctly. Furthermore we found that when procedures are mixed and matched in a way that is not theoretically coherent (for example, input oriented procedures in the clinic but an output oriented home practice program), we observed very poor outcomes. It is probable that in cases of poor implementation, outcomes and the therapeutic alliance will both suffer. At the very least, as I have found previously, parents are able to identify poor speech outcomes in their children even as they report good relationships with their child’s SLP.

This discussion reminds me of a very interesting article about teacher effectiveness that was circulated on twitter by @KevinWheldell. Gregory Yates makes the distinction between good teachers and effective teachers. Similarly SLPs may be readily judged to be good on the basis of personal and moral qualities such as warmth, caring, friendliness and conscientiousness, all of which contribute to positive relationships with clients, coworkers and their institution. Effectiveness requires the skillful application of specific techniques and procedures in relation to client needs however and can only be measured in reference to client outcomes. More about this in the next blogpost in this series.

Thinking About “Dose” and SLP Practice: Part I

A debate arose on @wespeechies about whether cumulative intervention intensity concepts, especially dose, are “too medical model” for speech-language pathology practice. Several objections were raised and I am going to address them singly in independent posts. One point of discomfort was the sense that talking about dose implies that the SLP does something to a passive patient in a context that is incompatible with both the biopsychosocial model of health care provision and collaborative models of service provision in the schools. These objections have been raised before in print, for example by Alan Kahmi although in his commentary he does not actually discuss dose but rather scheduling of treatment sessions which is a different concept altogether.

I want to defend the importance of the dose concept recognizing that one can of course rename everything if “medacalese” offends you, my dear readers. Our patients have become clients and the dose may be referred to as a “teaching episode” or a “learning opportunity”. Nonetheless, as Lise Baker said, thinking about dose forces us to identify the essential active ingredients in our interventions and structure our efforts to ensure that the child is receiving those active ingredients in the right amounts at the right time. The analogy to medical (pharmaceutical) treatments does not preclude the application of the biopsychosocial model at all and may in fact enhance our effectiveness in that regard.

Consider as an example, a kindergarten aged child with unintelligible speech who finds himself in daily conflicts, sometimes physical, during craft time that is deliberately structured by the teacher to encourage sharing and cooperation by the children. The value of the biopsychosocial model is that it forces us to think beyond the impairment level. What factors contribute to the difficulties that the child is having during craft time? Besides his inability to express himself clearly he may be lacking in social strategies for solving the conflicts that arise, having so little experience with successful conflict resolution. He is also likely to be very anxious in this situation and lacking in self-esteem generally. The SLP may elect to bring in another professional to help the child with the anxiety and self-esteem issues (personal factors), council the teacher to change the environment during craft time to reduce the opportunities for conflict (contextual factors) and to engage a teaching assistant (TA) support the child during craft time, and to personally attend craft time weekly to encourage the child to use words such as “black, blue, glue, please” more accurately in the classroom. Now we have a collaborative model that appears to be compatible with the biopsychosocial framework but will these interventions achieve the goal of improving the child’s competence to verbally resolve social conflicts? Unless the TA, the teacher and the SLP all have a clear idea about the what the active ingredients of the treatment are, it is quite possible that the treatment will not be effective, regardless of the number of times that the TA is available to mediate the child’s experience during craft time.

An excellent document entitled Making Best Use of Teaching Assistants points out that TAs tend to prioritize task completion over other goals. Therefore it is likely that the TA will sort out the materials for the child during craft time and help him to assemble them thus avoiding any possibility for conflict. The teacher will be happier and the parents will receive fewer distressing reports but the child’s self-esteem and sense of isolation will suffer further and bullying by other children may actually increase. What would the active ingredient of the intervention program be and how would we count the dose? The active ingredient is not support by the TA and the dose cannot be counted as successfully completed crafts. Rather, the goal is successfully negotiated “sharing” of craft materials and therefore the dose should be counted as the number of opportunities to use new strategies to obtain materials from another child. The child will need a means of communicating his needs clearly, strategies for resolving conflict that do not involve grabbing or hitting, reinforcement for engaging appropriately with the other children, and supports from the entire class that do not isolate or stigmatize him further. My readers are more qualified than I to work out the details of the intervention but it should be clear that intervention intensity is not the number or duration of supports provided; rather it is necessary to document the number of times the child practices specific behaviors that will eventually result in satisfactory levels of independent participation. It is also necessary to teach the TA to specifically ensure that these learning opportunities occur and to support the child’s achievement of the necessary skills in an appropriate fashion. Thinking clearly about the active ingredients of the intervention facilitates the success of the consultation process.

My point is that the intervention is not the SLP’s conversations with other staff or even the child. Currently, IEPs are often written in terms of applying units such as the TA or SLP to children (or teachers) for specified periods of time rather than a specific description of what the child needs to do in order to achieve successful functioning in the school environment. We spend a lot of time determining what the child (or school) is entitled to and not what the child needs. The intervention for our imaginary child is the number of times the he uses the relevant sentences in appropriate communicative contexts, experiences error and self-corrects, initiates interactions, and verbally resolves conflicts. From this perspective, thinking about doses of intervention units is the antithesis of passive actions on the child – it is all about the child’s opportunities to practice and learn the skills necessary to participate in his every day environment. I will come back to the issue of how best to promote learning during these teaching episodes in another post.

Support for Speech Perception Interventions in Speech Therapy

I am writing a third blog on this strange experimental protocol in which the talker produces a syllable repeatedly and the talker’s speech output is altered in a systematic fashion so that the talker hears him or herself say something that does not correspond to their own articulatory gestures. I am fascinated by these experiments because they are a window onto feedback control which is essential for a successful speech therapy outcome. Initially in traditional speech therapy the SLP is providing a lot of external feedback about the child’s articulatory gestures (knowledge of performance feedback) and the correctness of the child’s speech output (knowledge of results feedback). But given that the SLP cannot follow the child around outside the clinic room, eventually the child must learn to use self-generated feedback for speech motor learning to occur. Can children use auditory feedback to change their own speech?

In a previous blog, On Birds and Speech Therapy, I discussed interesting work from Queen’s University  suggesting that toddlers do not use feedback control like adults do during speech motor learning.  These researchers found that adults will compensate for perturbations of their own speech by adjusting their articulation to get the desired auditory feedback. In contrast, very young children do not compensate in this way. I suggested that this may be because toddlers do not perceive speech with the same degree of precision as adults. This hypothesis was supported by another study in which speakers of French and English did not show the same compensation effect to a perturbation that made their vowels sound like a French vowel. The English talkers did not respond to a perturbation to which they were not perceptually sensitive (see Feedback Control and Speech Therapy Revisited).

Recently, I was delighted to find another study involving children provides even stronger confirmation that perceptual representations play a key role in the child’s ability to use feedback for speech motor learning. Shiller and Rochon (2014)  randomly assigned 5- to 7-year-old children with typical speech to two training conditions: the control group received speech perception training for the /b/-/d/ contrast; the experimental group received speech perception training for the /ɛ/-/æ/ contrast. Prior to and subsequent to this training both groups experienced the perturbation experiment: both groups repeated said “Beb” while their own speech was altered to sound more like “Bab”. Prior to perceptual training, both groups showed a small compensation for this perturbation in the feedback of their own speech. After speech perception training the experimental group showed twice as much compensation as before whereas the control group showed no change in the amount of compensation.  The results show that children can indeed use feedback for speech motor adaptation; furthermore, this ability improves as perceptual boundaries between phoneme categories become better defined —with age or with training.

The conclusions of the study are very gratifying. Citing my own work on the importance of speech perception training as a strategy to facilitate speech production learning by children with speech sound disorders, the authors conclude:

“The results of the present study complement this work nicely, demonstrating that improvements in children’s auditory perceptual abilities do not simply improve motor performance, but also alter the capacity for auditory-feedback based speech motor learning—a process that is central to the clinical treatment of speech production disorders.” (p. 1314)

No surprise that I like this study a lot!

Top down or bottom up target selection with toddlers?

A new paper on the consonant repertoires of toddlers confirms the close relationship between early speech and language development: Sotto, C. D., Redle, E., Bandaranayake, D., Neils-Strunjas, J., & Creaghead, N. A. (2014). Fricatives at 18 months as a measure for predicting vocabulary and grammar at 24 and 30 months. Journal of Communication Disorders, 49, 1-12. Specifically these authors examined the relationship between consonant repertoires at 18 months and performance on the MacArthur-Bates Communicative Development Inventories: Words & Sentences (MBCDI: WS) at 18, 24 and 30 months. Although inventory size was not significantly correlated with vocabulary size and use of grammatical markers at 24 and 30 months, the presence of fricatives in the inventory at 18 months was associated with higher mean scores on the 24 and 30 month language tests in comparison to language test performance for toddlers who did not produce fricatives at the earlier age. The discussion nicely covers the many intervening variables that might account for this relationship. (Clarification added in response to reader questions: the children in the study were normally developing).

I was pleasantly surprised to find that all the raw data is presented in the paper so that the consonant repertoires for each of the 37 toddlers at 18 months could be examined directly. This allowed me to check whether these repertoires conformed to the expectations of the implicational hierarchy as described by Dinnsen et al in an older paper (the hierarchy is derived from earlier work by Jacobson I believe): Dinnsen, D. A., Chin, S. B., Elbert, M., & Powell, T. W. (1990). Some constraints on functionally disordered phonologies: Phonetic inventories and phonotactics. Journal of Speech and Hearing Research, 33(1), 28-37. The hierarchy takes a structural approach assigning the child to different levels on the basis of the phonetic feature “contrasts” that are present in the phonetic repertoire as shown in the table below, keeping in mind that the child does not have to use the phones contrastively; there need be only representatives of the opposing feature classes present in the repertoire. The hierarchy is said to be implicational because if a child produces the feature attributed to one level of the hierarchy it is theoretically impossible for the feature contrasts at any lower level to not be present. Therefore the presence of voiced and voiceless phones (Level B) implies the presence of labial and coronal place as well as obstruent, glide and nasal manner features (Level A). I examined each of the repertoires in the Sotto et al paper and determined the highest level represented for each child and noted any violations of the expectation of the implicational hierarchy. The results are shown in the table below.

Implicational Hierarchy

I find it to be very interesting that one third of the toddlers in this study do not meet the assumptions of the implicational hierarchy. For example if we consider the children who produced a Level C phonetic repertoire, in other words, the 24 22/37 toddlers who produced fricatives and or affricates, we find that 6 of these did so despite lacking glides (4 children) or nasals (2 children) in the inventory. In Dinnsen et al, 40 preschoolers with speech sound disorders were described and the 1 child that failed to meet the implicational assumptions of the hierarchy was assumed to have a “deviant” phonology. However, (as I have suggested for Dodd’s so-called “deviant” categories as well), deviant behaviors have a funny way of showing up in very early language development.

What are the implications of these data and my re-analysis for speech and language therapy? To be honest I am not sure. One thing that I am quite sure of is that the findings do not support the “complexity” approach to target selection – the idea proposed in Dinnsen et al is that treating Level E phone contrasts will cause the lower level contrasts to appear is if by magic because of the internally specified implicational relationship between the contrasts as if they were all linked together like Christmas tree lights. I have shown that this approach does not in fact work (see Rvachew & Bernhard, 2010). This is not to say that one should take the opposite approach by structuring your treatment approach to introduce features in the opposite direction, working your way up the levels from A to B (and contrary to some myths in circulation I have never recommended this). I think that the important thing to keep in mind is that children at this stage of phonological development are developing their phonology and their lexicons so as to enhance lexical contrast  rather than phonological contrasts and therefore one needs to take a language based core vocabulary approach in any case.

The problem that I have is that I have never been comfortable with the idea of picking any words that are “functional” and teaching them even if the child hasn’t a hope of approximating the word (those poor children with speech problems named Clarence are fortunately few!). I prefer to take a systematic approach introducing new phones to maximize the probability of success and the implicational hierarchy shown above is maybe not a bad start if you have a child with no consonant repertoire at all (this does happen sometimes). Another possibility is Daniel Ling’s approach (teach all manner classes at once at one place of articulation and then move to the next place, leaving voice contrasts to the end). On the other hand, given the broad variety of strategies evidenced by the children in the Sotto et al study maybe the notion of taking any words that are important in the child’s environment is both ecologically and theoretically defensible. I will come back with some summaries of Dodd’s work on the core vocabulary approach another time but I think that this is a problem worthy of more rigorous and empirical study with larger samples!

Introduction to the Wait Times Benchmarks Project

1. Introduction to the Wait Times Benchmarks Project

Access to speech, language, swallowing and hearing services is a critical concern across Canada. One indicator of the urgency of the problem is lengthy waits for service after a need has been  identified in one of these areas. Of course this issue is not restricted to communication health as attested by the Wait Times Alliance.  The Alliance was formed by doctors in 2004 to provide solutions to the problem of long waits for medical care in Canada’s publicly funded health service. Sadly, long waits for speech, language and hearing services are not specific to Canada, as reports in Australia and the United Kingdom have highlighted similar concerns to those raised by families by of children and adults who need services in Canada.

Although access to service is a multifaceted problem there are many reasons that wait times in particular invite a common focus by clients, service providers, funders, and politicians as the essential issue to target for improvement. The recent report by the Wait Times Alliance (Time to Close the Gap, Wait Times Alliance, 2014) lists several:

  1. it is established that many other countries with universal health care have succeeded in providing timely access to service and therefore we should not tolerate long waits when they are clearly not necessary;
  2. it can be shown that long waits for necessary services impose a significant burden on patients who are waiting as well as on society in general; and
  3. long waits for service impair health system performance such that improvements to wait times should result in gains for the system as a whole.

These considerations are as crucial for speech, language, swallowing and hearing health as for any other sector of the health care system. One step toward improvements in wait times is the development of benchmarks that indicate the maximum time that an individual should wait for service after taking into account the likelihood of significant clinical consequences should the wait  be longer. The Pan Canadian Alliance of Speech-Language Pathology and Audiology Organizations has committed to establishing reasonable wait times benchmarks as the first step toward reducing wait times for services.  A series of ad hoc committees recommended benchmark wait times for different diagnostic categories (see the Speech-Language and Audiology Canada (SAC) website). These wait times are being reviewed and reformatted according to a standard template and released publicly to the clinical community one at a time along with a published paper that provides the scientific foundation for each benchmark. The Benchmark Wait Times for Pediatric Speech Sound Disorders was released at the SAC Conference in May 2014 _and the associated Report was published in CJSLPA in Spring 2014 .The revised Benchmarks for Pediatric Language Disorders will be released soon and the Benchmarks for Fluency disorders are in progress.

In addition to releasing the benchmarks and the associated scientific reports, SAC will be providing additional information about benchmarks and their use in this blog which will be cross-posted to the SAC website and We will be inviting feedback and participation from the SAC membership or other interested commenters with each release. The schedule of upcoming blogs is shown below. We hope that you will follow the blog and consider commenting or contributing to this conversation.

Upcoming Posts

2. What is a Benchmark?

3. Approaches to Developing Wait Times Benchmarks

4. Evidence Based but not Evidence Bound

5. Use of Benchmarks by Clinicians and Policy Makers

6. Potential Advantages of Having Wait Times Benchmarks

7. Potential Disadvantages of Having Wait Times Benchmarks

8. Strategies for Achieving Wait Times Benchmarks

9. Factors that Impact on the Achievement of Wait Times Benchmarks

10. Role of the Pan Canadian Alliance and SAC in the Achievement of Wait Times Benchmarks

Wait Times Benchmarks for Speech-Language and Hearing Services

An important statement in the Universal Declaration of Communication Rights (International Communication Project 2014) is “We believe that people with communication disabilities should have access to the support they need to realize their full potential”. Even in those countries where speech-language pathology and audiology services are well established, long waits for service can be a significant barrier to communication for many children and adults. Twitter is a powerful tool for sharing knowledge and strategies for problem solving. This week on @WeSpeechies (see WESPEECHIES) we can share international perspectives on perceived appropriate wait times, actual wait times and strategies for reducing wait times for services around the world. When sharing information about this topic please identify yourself and provide general information about the nature of your clients and service sector while respecting privacy and confidentiality of specific individuals and organizations.

Q1. Approximately how long do your clients with speech-language needs wait for services? #WeSpeechies
Q2. Do you work with established expectations for wait times? How were the wait time benchmarks determined? #WeSpeechies
Q3. Do you think that clients with speech-language needs should have a guaranteed wait time for service? #WeSpeechies
Q4. What kind of criteria for deciding who gets served first are most fair? #WeSpeechies

Dose Frequency for Effective Speech Therapy

I am writing to address a specific question that has come up: in order to be effective when treating an “articulation disorder” how many trials should the SLP elicit from the client per treatment session? This is an important question and it is surprising that so little research attention has been directed at uncovering the answer. This is a question about what Warren, Fey and Yoder (2007) refer to as “dose: number of properly implemented teaching episodes per session”. We could be talking about the number of presentations of a model or perceptual responses by the child when conducting an “input oriented intervention” but in this blog I will restrict my comments to those interventions that are focused on obtaining speech responses from the child and therefore the teaching episode involves practicing a speech behavior such as a sound, syllable, word or phrase and each elicitation is counted as a single dose. In speech therapy the question of optimum dose frequency (how many trials per session of a given length) comes up most often in the context of Childhood Apraxia of Speech (CAS) where it is generally believed that practice intensity is particularly important. Recently, Murray, McCabe & Ballard (2014) reported that studies on approaches for CAS typically involved 60 to 120 trials per session whereas studies on approaches for phonological disorders typically involved 10 to 30 trials per session. The closest I have seen to an experimental investigation of dose frequency is the single subject experiments conducted by Edeal and Gildersleeve-Neuman (2011) in which low intensity (30 to 40 trials/session) versus high intensity treatment (100+ trials/session) was compared within two children with CAS. They concluded that “Both children showed improvement on all targets; however, the targets with the higher production frequency treatment were acquired faster, evidenced by better in-session performance and greater generalization to untrained probes.”

I don’t see any reason why a higher intensity intervention would not also be a “good thing” when treating children with a phonological disorder and indeed this is what Williams (2012) concluded when she reviewed data from her lab. After a quantitative summary of treatment outcomes for 22 children who received her multiple oppositions intervention she recommended a minimum dose of 50 trials over 30 sessions with anything less being ineffective and higher doses (70 trials or more) being necessary for the most severely impaired children. In this case the children received 30 minute sessions twice per week.

Recently we have been conducting single subject experiments with children who have CAS and although treatment intensity is not the primary focus of attention in these studies my doctoral student, Tanya Matthews, and I have been looking at the relationship between dose frequency and outcomes. In the figures shown below the children’s “next day probe scores” (an indicator of maintenance of learning over a short-term period, expressed as proportion correct) are shown as a function of the number of trials completed (top chart) as well as the number of correct trials in each session (bottom chart). There is not much variability in the number of trials per session because we put a lot of pressure on the student SLPs to keep this number high. However the number of correct trials varies quite a bit depending upon the severity of the child’s speech delay and whether it is early or late in the child’s treatment program. The lower chart shows that next day probe scores are better if the number of correct trials in each 20 minute practice session is above 60. The number of correct trials never goes above 80 because we are working to keep the child “at challenge point” so if the child begins to produce more than 80% correct trials we make the task more difficult. However, if the child is producing many errors it does not really help to keep the response rate high either because the child is just practicing the wrong response anyway.

So to sum up, notwithstanding the rather poor quality and quantity of the data, my impression is that dose counts: regardless of whether the child has a motor speech disorder or a phonological disorder it is important to achieve as many practice trials as you can in a treatment session but it is also a good idea to ensure that the child is achieving accuracy at the highest possible level of complexity and variability during practice as well.

Number of trials by probe score

Phonological Memory and Phonological Planning

I have been writing about the children in our intervention study for children with Childhood Apraxia of Speech (CAS). So far about half of the children referred to us appear to have difficulties in the domain of phonological memory with their overt phenotype corresponding to the subtype described by Dorothy Bishop Dodd as Inconsistent Deviant Disorder. Shriberg et al. (2012) have developed the Syllable Repetition Task as one means of identifying deficits in “memory processes that store and retrieve [phonemic, sublexical, and lexical] representations. We have been using this SRT test to differentiate children who have deficits in phonological planning versus motor planning. I described the profile that corresponds to difficulties with motor planning (transcoding) in a previous post. Today I will discuss the phonological memory or phonological planning profile that we see in approximately half of the children that are referred to us with suspected CAS.

These children can be identified by a qualitative analysis of their SRT performance and by their performance on the Inconsistency Test of the DEAP. Starting with the SRT, one child in our study for example was able to achieve 12/18 consonants correct when imitating 2-syllable items but only 5/18 consonants correct when imitating 3-syllable items, thus exemplifying the classic profile of a child with phonological memory difficulties – better nonword repetition performance for short versus long items. Qualitatively he tended toward consonant harmony errors even with some 2-syllable items, /bama/=[mama],  /maba/=[mama],  and then more frequently with the 3-syllable items, /nabada/=[mamada]. Addition of syllables and vowel errors also occurred, /manaba/ = [mamadada],  /manabada/=[mimadama]. Poor maintenance of phonotactic structure and vowel errors were also observed on the Inconsistency Test, “helicopter” = [hokopapɚ], “elephant”= [ɛmpɩnt], which yielded an overall inconsistency score of 78% as many words were produced with multiple variants, e.g., “butterfly”= [bʌtfaɩ], [bʌtwaɩ], [bʌtətwaɩ].

The most striking illustration of the difficulties these children have with the storage and retrieval of phonological representations comes during our treatment sessions however. In this research program we are teaching the children nonsense words in meaningful contexts. For example in one scenario we teach the children the names of “alien flowers” and in one of the treatment conditions we use graphic stimuli, paired with gestural cues if necessary, to represent the syllables and phonemes in the words and phrases that we are teaching. Many of the children in our study learn all of the nonsense words without difficulty (5 words per goal/condition introduced over 6 45-minute sessions). However children with the phonological memory difficulties have great difficulty learning the words (SLP: This is a speet. Say speet. Child: speet. That’s right, speet. What is it? Child: I don’t know. SLP: Yes, you do it’s speet, the purple one, the purple one is speet, remember, say speet. Child: ‘speet’. SLP, you’ve got it, the purple flower is speet, it’s a speet, what is it, it’s a … Child: um, I don’t know, and so on).


The most effective intervention to use with these children closely mirrors the procedures described by Barbara Dodd as the “core vocabulary” approach and demonstrated by Sharon Crosbie in the video that accompanies their chapter in the Williams, McLeod and McCauley (2010) book. The video is lovely and shows how to use graphic stimuli and a chaining procedure to teach the child to produce a word consistently – the idea is to encourage the child to develop and implement their own phonological/motor plan rather than relying on an imitative model. The children respond to this technique really well and will learn to say the new words such as “speet” and “stoon” quickly and accurately. The trouble begins when our student SLPs want the children to use the new words spontaneously in phrases (e.g., “water the speet”). They have great difficulty remembering the word or even the carrier phrase without the imitative model and I have to work really hard to teach the student clinicians to withhold the imitative model in favour of using other cues to stimulate spontaneous production of the target words and phrases (SLP: What is it? Let’s start with the snake sound here…).

We have wonderful video of student SLPs learning these techniques as well as children achieving their goals. Tanya Matthews and I will be presenting them at ASHA 2014. The difference in the way that you implement therapy with these children is subtle but important. I am pretty sure that Case Study 8-4 in our book had a phonological planning deficit rather than the motor planning disorder that he was treated for. I can’t help but think that if he was treated with these techniques he might have made some progress in the three years that we followed his case (whereas he made literally no progress at all until he was treated with a synthetic phonics approach in second grade). I’d love to hear from you if you have any other ideas about how best to treat children with phonological memory problems and inconsistent deviant disorder.




Auditory Motor Integration Intervention for CAS

In March 2013 I described the research we are conducting in my lab to identify individual differences in response to two different approaches to the treatment of Childhood Apraxia of Speech. I also described the unique single subject randomization design that we are using and presented some data for one child without revealing the interventions that corresponded to the condition that worked best for this particular child. We have subsequently replicated this result with another child so today I am going to write about the features of the intervention that children with difficulties in the area of transcoding appear to benefit from most clearly. Recall that transcoding is revealed in part by addition errors on the Syllable Repetition Task. In the case of the child profiled in the previous blog, he added nasal consonants at syllable boundaries when asked to repeat the syllable strings and he was just as likely to do this for short strings as for long, e.g., “mada” → [bᴂndə] and “manabada” → [mandabad]. This child also had difficulty with multisyllable repetition during the maximum performance tests but no difficulty with the single syllable diadochokinetic rate. Within word inconsistency was borderline with inconsistent word productions largely reflecting single feature errors (voicing errors for example). Altogether the impression is of a true apraxia or motor planning disorder (as opposed to a phonological planning deficit, a more common problem that I will describe in a future post). Thus far we have assessed 18 children in this study and remarkably only 3 have presented with this particular profile.

Two of these children have shown the best response to an intervention that is directed at promoting auditory-motor integration. It includes input-oriented procedures that are described in Chapter 9 of my book combined with output-oriented procedures described in Chapter 10. The procedures are used to promote the consistent use of stimulable phonemes in the context of word shapes that are difficult for the child so that the focus is more on holistic movement patterns at the whole word level than on individual phonemes. In the case described here we taught novel “monster names” that had a strong-weak-strong stress pattern and word internal coda consonants such as “Biftenope” and “Hapnidreem” and assessed for carry-over to phrases with similar structures (pumpkin pie, bat mobile). 

One reason that we designed an intervention approach that focused on auditory-motor integration is that there is evidence from the animal literature suggesting that this might be a foundational problem in the case of apraxia. Kurt, Fisher and Ehret examined sensory-motor association learning in mice with two different FoxP2 mutations. The task involved learning to avoid electronic shock by leaping a hurdle (or not) to the other compartment of a box in response to varied tones that signaled the location of the shock. Mice with either mutation were impaired in their response, one more severe that the other, in comparison to wild-type mice that learned the task without difficulty. The second reason that we designed an intervention with an auditory-motor integration component is that the ability to modify motor plans in response to auditory feedback and in relation to an auditory target is theoretically essential to the acquisition of speech motor control.

So what does an intervention that focuses on auditory-motor integration look like? Not surprisingly it has procedures that focus attention on the auditory-perceptual aspects of speech as well as procedures that focus on motor practice, none of the procedures themselves being novel or surprising. During the prepractice portion of each treatment we ensured that the child had a good perceptual representation for the target words using auditory bombardment and focused stimulation in meaningful contexts as well as error detection tasks as described in my teaching blog (scroll down to week 22). We also taught the child to monitor his own speech and respond differentially to his own correct or incorrect productions of the target words. For example an appropriate activity might be for the child “call” the monster and to then place the monster in his sleeping bag in the tent if he heard himself produce the name correctly or to place the monster in an alternative sleeping bag out in the rain if he heard himself produce the name incorrectly (our students are endlessly creative and this variation on the game has proved to be popular with the children this year).  The practice part of the session, for the most part, proceeds as one would expect for any child with CAS, focusing on high intensity practice while the SLP provides just enough stimulation prior to each attempt to elicit a correct response more often than not. However, every effort is made to avoid providing too much feedback. Working in blocks of five trials each, summative knowledge of results is provided whenever possible – this means that the child is given an opportunity to evaluate his own responses in relation to his own auditory goal without interference from SLP input, and then compare his own judgment with the SLPs count of correct responses at the end of each 5 trial run. Edy Strand writes about the importance of giving the child time to integrate feedback in her chapter with Derbertine in Caruso and Strand (1999) and describes precisely how to do this. Given a high rate of responses (over 100 trials per 20 minute practice session) and an average of 70% correct responses, this child was able to make excellent progress as measured by both same day and next day probes (see green bars on his chart here). A second child with the same profile also showed a significant benefit in favour of this approach. A third child is still being treated and it will be some time before we will know if he completes the protocol and then many more months before blind coding of his results will be finished. But, we are hopeful!


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