Feedback Control and Speech Therapy Revisited

In August 2012 I posted a comment about MacDonald, E. N., Johnson, E. K., Forsyth, J., Plante, P., & Munhall, K. G. (2012). Children’s development of self-regulation in speech production. Current Biology, 22, 113-117. (see On Birds and Speech Therapy). In this paper the authors reported that toddlers did not compensate for perturbations of their own vowel formants and they concluded that toddlers “do not monitor their own voice when speaking in the same way as adults do”. I was skeptical of this claim since it is hard to imagine how children learn to talk at all if they do not have access to feedback control mechanisms. I suggested that perceptual explanations would make more sense and now there is published evidence that this is indeed the case, interestingly from a paper including Munhall as author, specifically, Mitsuya, T., Samson, F., Ménard, L., & Munhall, K. (2013). Language dependent vowel representation in speech production. Journal of the Acoustical Society of America, 133, 2993-3003.

The paper is fascinating because it shows that English and French talkers to not show the same compensation effect when participating in this experimental paradigm and when the vowels involve French rounded vowel categories (i.e., English talkers do not change their own speech to compensate to a perturbation that makes their own speech sound more like a French vowel whereas French speakers do). Furthermore, the amount of compensation that a talker produces is related to the talker’s underlying phonological representation of the vowel space, as represented in acoustic-phonetic terms. In this study, when the English listeners did not respond to the particular perturbation of their vowel formants that was used, the researchers did not conclude that English people are incapable of using feedback control mechanisms! Rather they concluded that “the function of error reduction itself appears to be language universal, while detection of error is language specific.” However, the use of feedback for error reduction is dependent upon the talker’s perception of the feedback which in turn is related to the listener’s phonological representations (previously this was not clear because the research participants are not always consciously aware of the way that the experimenters are manipulating their speech).

Obviously the same logic should be applied to the toddlers’ apparent failure to use feedback control in a similar experimental manipulation in which the toddler’s speech was changed from one English vowel to sound a little bit more like another English vowel. In fact, a perceptually motivated interpretation is favoured in Mitsuya et al.; when referring back to McDonald et al. they say “a stable phonemic representation is required for error detection and correction in speech, and sometime between 2 and 4 yr of age such a representation emerges and stabilizes.” This is not the interpretation that made the headline in Science Daily but it is the conclusion that makes more sense to me.

What are the implications for speech therapy? The research clearly supports my view that it is essential to ensure that your clients with speech sound errors have stable perceptual and phonological representations – this is a critical component of a treatment program aimed at establishing speech motor control and speech articulation accuracy As Mitsuya et al suggest, the acoustic target for speech is not just the phonetic category itself but the target category in relation to its neighbors. The treatment approach that I have always advocated is focused on phonemic perception: the important procedures include presenting the child with a large population of variable exemplars of the target category. These exemplars should identify the centre of the category, highlighting the important cues and the prototypical characteristics, while also allowing the child to explore the edges of the category so that the child can experience it in relation to similar but contrasting categories. Thus SAILS  presents the child with a task in which highly variable stimuli are judged to be the TARGET or NOT THE TARGET and some of the stimuli are rather ambiguous. SLPs do not always like the fact that not all of the stimuli are prototypical exemplars of the target category but in fact this amount of variability is important for the establishment of phonological representations. Mitsuya et al.’s paper is important because it reinforces the point that stable acoustic-phonetic representations for speech targets are essential for the use of feedback control in speech motor learning.

Conversations with SLPs (2)

Some of you know that SAILS, my speech perception intervention software, is available for free to any speech therapist working with children who speak a North American dialect of English. The license is available from McGill University and I receive many requests every week along with some feedback and questions from users.  Gissella wrote to me with the following interesting question and I would like to share it and the answer with my readers:

“I am currently using the SAILS program with some children and have found it very helpful. I was wondering if the program could be used by parents with the help (training and treatment) of the treating S-LP. If that is possible, how would the parent go around getting the software.”

I answered that I am not comfortable with releasing the licence directly to parents because I would prefer that the parent be working under the guidance of an SLP so the best thing is for the SLP to apply for the license on behalf of the parent via flintbox .  (By the way I have worked out a way to make this old software run on 64-bit computers – you can download instructions in the revised BACKGROUNDER from the flintbox site. The tablet app is still under construction but I am hopeful that it will be available in 2014).

Further to the topic of parent application of SAILS, I also sent Gissella a copy of my paper – Rvachew, Nowak, & Cloutier (2004) – describing a randomized control trial in which we taught parents to administer SAILS to their children in the clinic, after their child’s regularly scheduled speech therapy session. Children in the control group played with Living Books after their speech therapy session and their parent asked them questions about the story according to sImagecripts that we provided. Both groups showed similar gains in phonological awareness but the SAILS (Sp Percn) group made dramatically better improvements in articulation accuracy as measured by number of errors on the Goldman-Fristoe Test of Articulation (see Figure inserted into this post) and by Percent Consonants Correct as reported in the paper. In that study we didn’t send SAILS home with the parents – as Gissella commented in a subsequent e-mail: “I now realize that the frequency of once per week seems to be sufficient, and therefore it can be done within the clinic most of the time, no need for the parent to do this at home.” This is absolutely correct, in all of my studies we have found that the intensity of the speech perception intervention does not have to be that great – a 20 minute session once per week during the first three sessions on a new phoneme works just fine.

In a follow-up e-mail, Gissella had another really interesting question however; “often times parents ask if they can have this program at home as they see it is easy to use and enjoyable for the child. There has been one case where we had treated the phonological delay, but there was residual articulation (frontal lisp) that will be treated at a later time. The parent had seen how SAILS worked for the phonology part and was interested in continuing exposing the child to the samples for /s/.”  I think that this would be a really interesting application for SAILS but unfortunately there is no empirical evidence to prove that this would be effective. I have always wanted to do a randomized control trial in which children with residual errors in kindergarten were treated with SAILS and then measures of speech accuracy, functional communication and psychosocial outcomes were collected at 6-month intervals for the next two years. Would we see more cases of “spontaneous” resolution of the residual errors in the SAILS group than in the control group? Unfortunately I can’t get decent funding for randomized control trials that involve even children with severe speech sound disorders so I doubt that I could get enough funding for something like this (to have enough statistical power it would have to be a big multisite study with a lot of funding even though 18 percent of 8 year olds can be expected to have speech errors; see Roulstone et al., 2009). You cannot believe how often other researchers, even those working in the field of speech sound disorders, tell me that this most common of neurodevelopmental disorders is just “not important” (see Bishop, 2010)!

Online Gaming and Speech Therapy

I have just read this marvelous paper tweeted out by @vaughanbell: Stafford, T., & Dewar, M. (2013). Tracing the Trajectory of Skill Learning With a Very Large Sample of Online Game Players. Psychological Science. He was impressed by the very large sample size (N = 854,064) but I am impressed by the relevance of this paper for speech therapy. The researchers used “detailed records of practice activity from an on-line game” and used it to test hypotheses about learning in the game which requires “rapid perceptual decision making and motor responses”. Gratifyingly for us as speech-language pathologists, the results confirm the principles of motor learning that are currently promoted for successful treatment of childhood apraxia of speech (CAS), specifically practice intensity, distributed practice and variable practice conditions (for application of these principles to the treatment of apraxia of speech see for example Gildersleeve-Neuman in the ASHA Leader or Tricia McCabe’s ReST program).

There was one concept raised in the paper that was a little bit novel with respect to the CAS literature however: specifically, the authors talk about the “exploration/exploitation” dilemma. In the context of this simple but bizarrely fun computer game (found here at The Welcome Collection)  you can explore the axon growing environment when first learning to play or you can settle into a strategy of simply clicking on the closest protein in your circle of influence. The latter strategy will work to grow your axon which is the object of the game but you will miss out on learning how to maneuver your circle of influence so as to actively find the “power proteins” that advance the growth of your axon. Exploration has a cost in that it leads to more variable performance early on but the benefit is potentially better performance with longer experience. In fact, Stafford et al. observed a close relationship between higher early variance in performance and better performance during later attempts. This trade-off between exploration and exploitation reminded me of the importance of the expansion stage in early speech development and the implications for intervention with young children with CAS.

In Table 10-1 of Developmental Phonological Disorders: Foundations of Clinical Practice we suggest learning outcomes and therapeutic strategies to correspond to four stages of speech development as follows: 1. Expansion stage (explore possibilities of the vocal system); 2. Babbling and integrative stage (controlled variability); 3. Early speech development (expanding repertoire of phones and word shapes to achieve intelligible speech); and 4. Late speech development (ongoing refinements to achieve adultlike speech accuracy and precision). These stages are described in greater detail in Chapter 3 which covers the literature on the development of speech motor control. The expansion stage typically occurs during months 3 through 6 and is characterized by a variety of vocalizations that are not very speech-like (squeals, growls, raspberries and so on) as well as the appearance of fully resonant vowels and marginal babble. It is my experience that SLPs do not appreciate the importance of the expansion stage to normal speech development or understand its significance when planning an intervention program for children with limited if any speech capacity. Therefore I highlight this point in Chapter 10, as follows:

“The importance of the expansion stage in the laying of building blocks for later speech development is easy to forget when choosing goals for speech therapy, a topic to which we return shortly. Another important achievement during the infant period is the acquisition of canonical syllables when the child learns to control the variable parameters explored during the expansion stage, coordinating them to produce well-formed syllables in the context of babble, jargon, and early words. …Typical descriptions of speech acquisition focus on reductions in variability with age. … Therefore, it is not surprising that traditional speech therapy procedures are designed to enhance consistency and reduce variability in the production of phonemes with practice. However, variability is not always an impediment to speech learning and children with DPD often suffer from insufficient variability in their repertoire of speech behaviors. Performance variability can be viewed as facilitating, detrimental, or irrelevant to a successful outcome depending on the motor learning context (Vereijken, 2010). For example, the highly variable vocalizations of the expansion stage provide a complex foundation for the emergence of speechlike vocalizations at later stages. Infants who are described as being “quiet” during the first year of life lack sufficient variability for normal motor speech development. The normally developing infant harnesses rather than reduces this variability to coordinate the separate respiratory, phonatory, resonance, and articulatory components to produce babble in the next stage. Throughout the next 16 or so years there will be a continual interplay between adaptive variability to meet new challenges and increased stability to enhance precision. (p. 758)”

 I often talk to SLPs who are frustrated by failed efforts to teach new phones via imitation to children with severe speech sound disorders. However children with limited vocal repertoires must first be encouraged to freely explore their vocal systems. I describe procedures to encourage vocal play in detail in the book, following Dethorne, Johnson, Walder, and Mahurin-Smith (2009) and supplementing with examples of implementation from my own clinical experience. I hope that Stafford et al.’s interesting research and this amusing little game leads to more reflection about the role of exploration and variability in speech motor learning.

Historical Perspective on Tactile Approaches to Speech Therapy

Recently Caroline Bowen on Twitter (@speech_woman) alerted us to a new fad, therapeutic massage. Of course, the therapy techniques being promoted on the website that Caroline linked to and in the workshops offered by the person in question are not new at all. I recognized them immediately as being very very old and the historical basis for other techniques that are in current use such as tactile cueing and PROMPT. The description of therapeutic massage that was offered (I’m sorry, I refuse to link to the site) put me in mind of Charles Van Riper’s brilliant response to the Motokinesthetic Method which I reproduce here for your edification and enjoyment:

“We have previously mentioned the Motokinesthetic Method invented by Edna Hill Young as one of the approaches used in teaching a child with delayed speech to talk. It has also been used in the elimination of misarticulations. Essentially, this method is based upon intensive stimulation; however, the stimulation is not confined to sound alone but to tactile and kinesthetic sensations as well. The therapist, by manipulation and stroking and pressing the child’s face and body as she utters the stimulus syllable, helps him recognize the place of articulation, the direction of movements, the amount of air pressure, and so on. Watching an expert motokinesthetic therapist at work on a lisper is like attending a show put on by a magician. The case lies on a table with the therapist bending over him. First she presses on his abdomen to initiate breathing as she strongly makes the s sound; then to produce a syllable from the patient, her fingers fly swiftly to close his jaws, spread the lips, and tap a front tooth, thereby signaling a narrow groove of the tongue or the focus of the airstream. Then her magical fingers squeeze together to draw out the sibilant hiss as a continuant.

One therapist, when working with a child,  used to “draw out” the s, wind it around the child’s head three times then insert it into her ear, thus insuring that it would be prolonged enough to be felt. Each sound has its own unique set of deft manipulations, and considerable skill is required to administer motokinesthetic therapy effectively. Viewed by the cold eye of the modern speech scientist, many of the motokinesthetic cues seem inappropriate; and a therapist would need sixty fingers and thirty arms to provide sufficient cues to take care of the necessary integration and coarticulation. Moreover, much of our research has indicated that standard sounds are produced in different ways by different people, and that their positioning vary widely with differing phonetic contexts. We suspect that much of the effectiveness of this method is due to its powerful suggestion (the laying on of hands), to its accompanying auditory stimulation, or to the novelty to the situation, which may free the case to try new articulatory patterns. We have used it successfully with some very refractory cases, but we always have felt a bit uncomfortable when doing so, as though we were the Magical Monarch of Mo in the Land of Hocus Pocus. (p. 198-201).”

This is just one of many delightful passages from Van Riper’s book “Speech Correction: Principles and Methods” (1978 Prentice-Hall edition but first published in 1939). Characteristically, this passage shows Van Riper to be far ahead of his time. Tactile approaches to speech therapy just seem to make sense because, as I heard numerous times at the ASHA conference last week, “speech comes from movement”. However, a point I make repeatedly in our book Development Phonological Disorders , I believe that this perspective is subtly backwards. Speech movements are learned through practice. The practice is motivated by the desire to achieve functional goals. Learning involves linking knowledge of the goal with the movements used to achieve the goals. The movements are learned through the process of achieving goals which are phonetic, phonological and ultimately linguistic in nature. In another post I will talk more about the issues with trying to shape those movements articulator-by-articulator.

Which SLPs are Effective?

In my last two blog posts I have been talking about how to ensure that your speech therapy program “works”, in other words, how can you be sure that what you do is effecting change in your patient over and above the change that would occur due to maturation and history effects alone? I have suggested that if you choose treatment approaches that have been validated via randomized controlled trials as effective approaches and if you demonstrate that your patient is improving you can be reasonably sure that you are having a positive effect on your patient. I have further cautioned that you need to read the original research carefully and implement the treatment approaches in accordance with the treatment efficacy trials with respect to procedures, treatment intensity and so on in order to ensure that you will get the same effect. These details – the treatment procedures that you decide to implement with your patient – are referred to as the specific ingredients of your treatment program. Throughout my research career I have been focused on the relative efficacy of these specific ingredients – is it effective to use perception training or stimulability training or prepractice with visual cues in comparison to usual care? For example, one-year follow-up of the children treated in Rvachew, Nowak and Cloutier (2004) showed that 50% of the children who received usual care + speech perception training started school with normalized speech versus only 19% of the children who received usual care + dialogic reading. I obviously feel that an important role of the SLP is to know the scientific literature and choose the right specific ingredients for their patients.

In contrast, Ebert and Kohnert (2010) point out that the effectiveness of speech therapy might also be due to “common factors” which include (following Grencavage and Norcross): the patient, the clinician, and the patient-clinician alliance, change processes, and treatment structure. Studies on the effectiveness of teachers and psychotherapists are starting to appear with increasing frequency but I am not aware of any published systematic studies of SLP effectiveness that take a “common factors” approach. Ebert and Kohnert re-analyzed the data from one of my studies (Rvachew and Nowak, 2001, discussed in my previous blog) and concluded that although target selection strategy accounted for a larger proportion of variance in outcomes, individual differences in clinician effectiveness accounted for 20% of variance in outcomes. These researchers surveyed SLPs in Minnesota and asked them to rate various factors for their importance in determining client outcomes. The results showed that SLPs weight client-clinician factors very highly with “rapport” being the item rated as having the greatest impact on therapeutic outcomes. Recently Geraldine Wotton wrote a blog post on the power of the therapeutic relationship that expresses this commonly held view. The thing is however, I knew the SLPs who provided the intervention in Rvachew and Nowak and I can tell you that there were no discernible differences in rapport between these SLPs and their clients. Furthermore, at the time I was the research coordinator for allied health in the hospital and I was responsible for the client satisfaction questionnaire in the hospital. Families reported high levels of satisfaction with their clinicians while reporting varying levels of satisfaction with their child’s outcomes. I was always impressed by the fact that parental satisfaction with their child’s speech outcomes and objective measures of child outcomes were highly correlated (given that I was running several RCTs at the time I could look at this) but uncoupled from uniformly high satisfaction ratings for their relationship with the therapist. I certainly agree that the strong positive relationship between SLPs and their patients is an important factor in treatment efficacy – I just don’t agree that it explains variations in treatment outcomes: think about this carefully – SLPs are selected to have strong interpersonal skills and we are very good at establishing rapport with our patients but we do not all get the same results. There is something else going on here.

Françoise and I recently completed a RCT involving 72 francophone children in which the clinicians were student SLPs from McGill. We have 6 videorecorded therapy sessions for each child, representing more than a dozen student SLPs. Unfortunately we have run out of funds so we haven’t been able to analyze all the video but two students, Amanda Langdon and Hannah Jacobs, obtained summer research bursary funds from the Faculty of Medicine to conduct a pilot project in which they coded the videos for 6 student clinicians, attempting to identify common factors that might differentiate between more and less effective SLPs. In this case the supervising clinical educators told us which student SLPs were more or less effective in their opinion, rating them as “accomplished” or “struggling”. Then Hannah and Amanda coded the videos for factors related to the clinician, the clinician-child alliance and to change processes. Interestingly the factors that differentiated “accomplished” versus “struggling” student SLPs were not those that would be ascribed to the “clinician” category in Glencavage and Norcross’ model. Rather we found large differences in variables that could be categorized as “change processes”. In Glencavage and Norcross’ paper a lot of the factors categorized as change processes are specific to psychotherapy but some are common to speech therapy as well, for example “acquisition and practice of new behaviors”, “provision of a therapeutic rationale”, “naming the problem”, and “contingency management”. Applied to speech therapy we can hypothesize that SLPs may vary in their ability to communicate and/or negotiate the goals of the therapy program to or with the patient, maintain a high response rate during sessions so as to ensure that most of the session is spent practicing new behaviors, and manage contingencies so that the patient is receiving appropriate feedback about their responses during practice. We observed changes in these skills across the six week treatment program for student SLPs who were rated to be “accomplished” or “struggling” by their supervising clinical educators. We found that all the students increased the amount of time devoted to direct therapy in their sessions during the course of their practicum. Accomplished students began with good contingency management skills and improved those skills to an even higher level after six weeks of practice. On the other hand, struggling students began and ended the practicum with poor contingency management skills – in particular these students did not provide appropriate feedback after incorrect responses by their clients. Interestingly, in comparison to struggling students, accomplished students spent more rather than less time in “off task” behavior which may mean that they had more resources available for conversation that served to establish rapport with their clients. Struggling students spent a lot of time “manipulating materials” and therefore their disorganized approach to the therapy sessions may have interfered with the SLP-client alliance. Unfortunately this study is tiny; the coding is hugely time consuming and expensive. However I think that it is crucial for our profession that resources be expended to study these therapeutic processes and the means to improve our students’ skills in learning these skills during their preprofessional practice.

I’d love to hear from student SLPs about your experiences with learning these skills. What do you think your clinical educators could do to help you learn these skills? I’d also love to hear from practicing SLPs – do you agree that skill in the engagement of change processes is an important factor in therapeutic effectiveness? Which change processes do you think are most important in speech therapy?

Don’t get tricked: Why it pays to read original sources.

In my last blog post I suggested that you can have confidence in the effectiveness of your clinical practice if you select treatment practices that have been validated by research. Furthermore, I provided links to some resources for summaries of research evidence. In this blog post I want to caution that it is important to read the original sources and to view the summaries, including meta-analyses, with some skepticism. Excellent clinical practice requires a deep knowledge of the basic science that is the foundation for the clinical procedures that you are using. Familiarity with the details of the clinical studies that address the efficacy of those procedures is also essential. I will provide two examples where a lack of familiarity with those details has led to some perverse outcomes.

Two decades ago it was quite common for children who were receiving services from publically funded providers in Canada to receive 16-week blocks of intervention. Then we went through the recession of the nineties and there was much pressure on managers in health care to cut costs. Fey, Cleave, Long, and Hughes (1993) conveniently published an RCT demonstrating that a parent intervention was just as effective as direct intervention provided by the SLP to improve children’s expressive grammar – the icing on the cake was that the parent-provided service required half as many SLP hours as the direct SLP-provided service. All across Canada, direct service blocks were cut to 8 weeks and parent-consultation services were substituted for the direct therapy model. About a decade after that I made a little money myself giving workshops to SLPs on evidence based practiced. The audiences were always shocked when I presented the actual resource inputs for Fey et al.’s interventions: (1) direct SLP intervention –  cost = 40 hours per child over 20 weeks, versus (2) parent administered intervention – cost = 21 hours per child over 20 weeks. So you see, the SLPs had been had by their managers! The SLPs would have been better positioned to resist this harmful change in service delivery model if they had been aware of the source of the claim that you could halve your therapy time by implementing a home program and get the same result. I don’t know that our profession could have changed the situation by being more knowledgeable about the research on service delivery models because the political and financial pressures at the time were extreme – but at least we and our patients would have had a fighting chance!

Another reason that you have to be vigilant is that the authors of research summaries have been known to engage in some sleight of hand. An example of this is chapter on Complexity Approaches by Baker and Williams in the book Interventions for Speech Sound Disorders in Children. This book is pretty cool because each chapter describes a different approach  and is usually accompanied by a video demonstration. Each author was asked to identify all the studies that support the approach and put them on a “levels of evidence” table. As indicated in a previous blog post, the complexity approach to selecting targets for intervention is supposedly supported by a great many studies employing the multiple probe design which is a fairly low level of evidence because it does not control for maturation or history effects. In the Baker and Williams “levels of evidence” table all of these single subject studies are listed  so it looks pretty impressive. The evidence to support the approach looks even more impressive when you notice that two randomized controlled trials are shown at a higher level on the table. This table leads you to believe that the complexity approach is supported by a large amount of data and the highest level of evidence until you realize that neither of those two RCTs, Dodd et al. (2008) and Rvachew and Nowak (2001), support the complexity approach. Even when you read the text, it is not clear that these RCTs do not provide support for the approach because the authors are a bit wafflely about this fact.  Before I noticed this table I couldn’t understand why clinicians would tell me proudly that they were using the complexity approach because it is evidence based. It is pretty hard to keep up with the evidence when you have to watch out for tricks like this!

In the comments to my last blog post there were questions about how you can be sure that your treatment is leading to change that is better than maturation alone. An RCT is designed to answer just that question so I am going to discuss the results of Rvachew and Nowak (2001), as detailed in a later paper, Rvachew, S. (2005). Stimulability and treatment success. Topics in Language Disorders. Clinical Perspectives on Speech Sound Disorders, 25(3), 207-219. Unfortunately this paper is hard to get so a lot of SLPs are not aware of the implications of our findings for the central argument that motivates the use of the complexity approach to target selection.  Gierut (2007) grounds the complexity approach on learnability theory, paradoxically the notion that language is essentially unlearnable and thus the structure of language must be innately built in. Complex language inputs are necessary to trigger access to this knowledge. Because of the hierarchical structure of this built-in knowledge, exposure to complex structure will “unlock the whole”, having a cascading effect down through the system. On the other hand, she claims that “it has been shown that simpler input actually makes language learning more difficult because the child is provided with only partial information about linguistic structure (p. 8).”

We tested this hypothesis in our RCT. Each child received a 15 item probe of their ability produce all the consonants of English in initial, medial and final position of words. The phonemes that they had not mastered were then ordered according to productive phonological knowledge and developmental order. Michele Nowak selected potential treatment targets for each child from both ends of the continuum. I independently (blindly, without access to the child’s test information or knowledge of the targets that Michelle had selected) randomly assigned the child to treatment condition, either ME or LL. ME condition means that the child was treated for phonemes for which the child had most knowledge and which are usually early developing. LL condition means that the child was treated for phonemes for which the child had least productive phonological knowledge and which are usually late developing. The children were treated in two six week blocks with a change in treatment targets for the second block using the same procedure to select the targets. The figure below shows probe performance for several actual and potential targets per child: the phoneme being treated in a given block, the phoneme to be treated in the next block (or that was treated in the previous block) and the phonemes that would have been treated if the child had been assigned to the other treatment condition. As a clinician, I am interested in learning and retention of the treated phonemes, relative to maturation. As a scientist who is testing the complexity approach, Gierut is interested in cross-class generalization, regardless of whether the child learns the targeted phoneme. We can look at these two outcomes across the two groups.

Let’s begin with the question of whether the children learned the target phonemes and whether there is any evidence that this learning is greater than what we would see with maturation alone. In the chart, learning during treatment is shown by the solid lines whereas dotted lines indicate periods where those sounds were not being treated. A1 is the assessment before the first treatment block, A2 is the assessment after the first block and before the second block, and A3 is the last assessment after the second treatment block. On the left hand side, we see that the ME group was treated during the first block for phonemes that were mastered in one word position but not in the other two (average score of 6/15 prior to treatment). The slopes of the solid versus dotted lines show you that change from A1 to A2 was greater than change from A2 to A3. This means that these targets showed more change when they were being treated in the first block than when they were not being treated during the second block. During the second block, we treated slightly harder sounds that were not mastered in any word position, with a starting probe score of 3/15 on average. These phonemes improved from A1 to A2 even though they weren’t being treated but the rate of improvement is much higher between A2 and A3 when they were being treated. Interestingly, the slopes of the solid lines and the slopes of the dotted lines are parallel – this is your treatment effect – this is the proof that treatment is more effective than not treating. As further proof we can look at the results for the LL group. We have a similar situation with parallel solid and dotted lines for the phonemes that were treated in the first and second blocks at the bottom of the chart. We don’t have as much improvement for these phonemes because they were very difficult, unstimulable late developing sounds (targets that are consistent with the complexity approach). None-the-less the outcomes are better while the phonemes are being treated than when they are not (in fact there are slight regressions during the blocks when these sounds are not treated). At the same time, the phonemes for which the children have the most knowledge improve spontaneously (Gierut would attribute this change to cross-class generalization whereas I attribute this change to maturation). The interesting comparison however is across groups. Notice that the ME group shows a change of 4 points for treated “most knowledge” phonemes versus a change of 3 points for the untreated “most knowledge” phonemes for the LL group. This is not a very big difference but none-the-less, treating these phonemes results in slightly faster progress than not treating them.

In our 2001 paper we reported that progress for treated targets was substantially better for children in the ME condition than for children in the LL condition (in the latter group, the children remained unstimulable for 45% of targets after 6 weeks of therapy). However, the proponents of the complexity approach are not interested in this finding. If the child does not learn the hard target that is an acceptable price to pay if cross-class generalization occurs and the child learns easier untreated phonemes. If you look at the right hand side of the chart by itself, the chart can be taken as support for the complexity approach because spontaneous gains are observed for the “most knowledge” phonemes. The problem is that the proponents of this approach have argued that exposure to “simpler input actually makes language learning more difficult” – it is literally supposed to be impossible to facilitate learning of harder targets by teaching simpler targets. Therefore the real test of the complexity approach is not in the right hand chart. We have to compare the rate of change for the unstimulable targets across the two groups. It is apparent that the gain for UNTREATED unstimulable phonemes (ME group, gain = 2) is double that observed for TREATED unstimulable phonemes (LL group, gain = 1). The results shown on the left clearly show that treating the easier sounds first facilitated improvements for the difficult phonemes. I have explained this outcome by reference to dynamic systems theory in Rvachew and Bernhardt (2010). From my perspective, it is not just that my RCT shows that the complexity approach doesn’t work. It’s that my RCT is just part of a growing and broad based literature that invalidates the “learnability approach” altogether. Francoise and I describe and evaluate this evidence while promoting a developmental approach to phonology in our book Developmental Phonological Disorders: Foundations of Clinical Practice.

 

Probe Scores for Treated and Untreated Phonemes

Probe Scores for Treated and Untreated Phonemes

 

 

 

 

 

 

 

 

The larger point that I am trying to make here is that SLPs need to know the literature deeply. The evidence summaries tend to take a bit of a “horse race” approach, grading study quality on the basis of sometimes questionable checklists and then making conclusions on the basis of how many studies can be amassed at a given level of the evidence table. This is not always a clinically useful practice. It is necessary to understand the underlying theory, to know the details of the methods used in those studies, and to draw your own conclusions about the applicability of the treatments to your own patients. This means reading the original sources. In order to achieve this level of knowledge we need to reorganize our profession to encourage a greater number of specialists in the field because no individual SLP can have this depth of knowledge about every type of patient that you might treat. But it should be possible to encourage the development of specialists who are given the opportunity to stay current with the literature and provide consultation services to generalists on the front lines. Even if we could ensure that SLPs had access to the best evidence as a guide to practice however, there are some “common factors” that have a large impact on outcomes even when treatment approach is controlled. In my next post I will address the role of the individual clinician in ensuring excellent client outcomes.

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.

Extraterrestials and Speech Therapy

I am somewhat disheartened to stumble across another paper, based on a case study of a single child, advising speech-language pathologists to focus treatment on speech production while ignoring the child’s obvious difficulties with speech perception (McAllister Byun, 2012). The problem that I have with this paper is not that it is a case study (these can be very useful in clinical and research contexts) but that the conclusions are based entirely on phonetic transcriptions of a child’s speech and of the speech stimuli used to assess the child’s perceptual abilities. I believe that this leads to what is probably an erroneous conclusion about the child’s speech production accuracy. This may be alarming to clinical readers since phonetic transcription is your primary tool for describing children’s phonological knowledge. However, in a recent paper Munson et al (2010) explains why it is not clear that “alien anthropologists would come up with anything remotely like phonetic transcription to characterize human speech”. Extraterrestials with a different communicative apparatus may be better placed to realize that phonetic transcription provides a highly biased and often inaccurate picture of what the child is doing when articulating the phonemes that we are testing in our assessments. Munson and colleagues present compelling data to that effect but concede in the conclusions that the extraterrestials may also come to realize that humans usually don’t have the time or resources to obtain unbiased data via instrumental analyses. However, if we must use phonetic transcription we must at least be aware of the limitations so that we can avoid the error that is made in McAllister Byun’s case study. For I believe that there is a significant error that will do harm to children in speech therapy unless we understand the points made in Munson’s fantasy about extraterrestial anthropologists.

McAllister Byun begins by acknowledging that it is now well accepted that speech perception difficulties are associated with speech production errors which is a good thing because I am real tired of devoting research time to proving that over and over again. In fact I got bored with that question a long time ago and went on to the next step – establishing direction of causality. Theoretically, difficulties with speech production accuracy could precede and cause misperception of speech sounds and in fact I was taught that this was so when I studied speech therapy at the University of Alberta in the 1970s. McAllister Byun updates the idea with an intriguing explanation for this hypothetical effect involving the role of the child’s own productions in the population of exemplars that contribute to the child’s perceptual knowledge of the target phoneme. The clinical implications of this hypothesis (if true) are clear; if the child misarticulates /k/ → [t], teach the child to articulate /k/ correctly and any misperception of the contrast will correct itself. On the other hand, misperception of the /k/-/t/ contrast could precede and cause the failure to acquire the appropriate articulatory gestures for accurate production of the /k/ phoneme. I think that this latter hypothesis makes sense because the infant’s speech perception skills begin to develop at least six months in advance of the production of speech-like articulation (in the form of babble) and therefore I think that speech perception typically precedes speech production development although there is a reciprocal relationship in the acquisition of precision in both domains throughout childhood. This hypothesis is also consistent with the DIVA model of speech motor control as described in Shiller, Rvachew & Brosseau-Lapré (2010). I have supported this hypothesis with four types of studies: (1) linear structural equation modeling showing good fit to the “perception leads production” hypothesis and poor fit for the alternative (Rvachew & Grawburg, 2006); (2) a longitudinal study showing that perception skills predict growth in articulation accuracy but not the reverse (Rvachew, 2006); (3) single subject experiments showing that treating speech perception increases speech production accuracy (Jamieson & Rvachew, 1992); and (4) randomized control trials showing that speech perception and speech production training combined is much more efficient and effective than speech production training alone (for review see Chapter 9, Rvachew & Brosseau-Lapré, 2012). Furthermore, in one of these trials I showed specifically that speech production training did not lead to improved speech perception (Rvachew, 1994). Therefore, I recommend that speech perception and speech production treatment procedures be conducted in parallel, with the “input oriented” activities preceding the “output oriented” activities to a greater or lesser extent depending upon the needs of the child. Should I reconsider these recommendations, based on over 30 years of clinical practice and research findings, after reading McAllister Bryn’s paper? Not at all – let’s look at it carefully.

McAllister Byun describes a 4-year-old boy who was given a “provisional diagnosis of CAS…based on the presence of characteristics including atypical prosody, inconsistent errors and vowel errors…” (p. 402). The child fronted velars in syllable onsets (referred to as “strong position”) but not in syllable codas (referred to as “weak position”). This is thought to be an anomaly because implicational relationships dictate that accuracy in the weak position implies accuracy in the strong position. Redford & Diehl (1999) is cited as evidence for greater perceptual prominence of the onset position (making it the strong position). If you read Redford and Diehl however you find that the adults in their study did not find perception of /k/ to be easier in the onset compared to the coda (these relationships were phoneme specific and therefore gross generalizations about positional prominence should not be made). More to the point, the child’s perception of /k/-/t/ was tested using a perceptual test based on same-different judgments of recorded natural speech stimuli. The results revealed equally poor discrimination performance for the /k/-/t/ contrast in onsets and codas. The author concluded that, in this case, production accuracy was “leading” the child’s acquisition of perceptual knowledge of the contrast. The author further concludes that, for this particular case, the deficit in perception could be attributed to “a primary deficit in production” and therefore “motor-oriented therapy may be optimal”. If you believe that speech development is an “either-or” affair where the phoneme contrast is discriminated or not discriminated in the perceptual domain and the target phoneme is produced correctly or not in the articulatory domain, I suppose that this might make sense. However, speech development is a process of gradually acquiring knowledge of multiple phonetic characteristics that are distributed in a continuous fashion across the category. Studies of children’s phonetic knowledge of phoneme categories show that it is not a safe assumption that this child had achieved articulatory accuracy for /k/ in the coda position in advance of perceptual knowledge of the /k/-t/ contrast.

In our book, Françoise and I stress repeatedly that it is not enough to ask if the child perceives any given contrast. Rather, we want to know “how” the child perceives the contrast: “Phonetic categories are an emergent property of the distribution of acoustic information across parametric phonetic space, built up over time as the language learner stores detailed memory traces of experienced words. Each language learner must discover a strategy for abstracting phonetic structure from the input that is adapted to the nature of the input that is received. Assessing the language learner’s perceptual knowledge requires sophisticated tools that reveal the listener’s perceptual strategies for making sense of highly complex and variable input …” (p. 46). The test used by McAllister Byun clearly does not meet this standard-we have no way of knowing which acoustic cues the child was attending to when completing the task. The acoustic cues for perception of /k/ include all the spectral moments (mean, variance, skewness and kurtosis) that can be measured for the stop burst (Forrest et al. 1990) as well as many acoustic characteristics of the formant transitions that tie the release burst to the vowel (Dorman et al, 1977; Nguyen et al, 2009). Adults and children with normally developing speech differentiate /k/ and /t/ in production  largely on the basis of the spectral mean. Three different patterns are seen among children with speech disorders: (1) they may not differentiate the phonemes at all (i.e., they have no contrast) or (2) they may produce a covert contrast (their /k/ targets are perceived as [t] even though they are acoustically different from /t/ targets) or (3) they may produce a perceptible /k/-/t/ contrast that is differentiated on the basis of nonstandard cues. Nonstandard cues in the latter two situations may include skewness and kurtosis in the burst; alternatively the child may ignore the burst and manipulate slope of the formant frequency transitions. Reliance on non-standard cues or cue-weighting strategies in perception may lead to variable performance in perception and production.

How might a child with incomplete knowledge of the acoustic properties of this contrast achieve perceptually accurate production in codas and inaccurate production in onsets?  Using electropalatography, Gibbon & Wood (2002) describe “articulatory drift” whereby placement of an undifferentiated lingual gesture at onset is different from the placement at release, resulting in variable perceptual outcomes for alveolar and velar targets, such that /t/ → [t, k] and /k/ → [t, k]. Gibbon (1999) demonstrated how a child can learn to control the release phase of the gesture to achieve the contrast without fundamentally changing the undifferentiated lingual gesture itself. In this case, the adult listener believes that the child has acquired the contrast productively but the child’s underlying articulatory patterns continue to be immature.

I actually think it makes sense that the child’s own productions might have some sort of downstream effect on the child’s perception of a phoneme contrasts. Perhaps McAllister Byun’s case is an example of that, especially given the “provisional diagnosis of CAS” in this case. However, the assessment information provided is inadequate to prove the hypothesis. We do not know which acoustic cues the child attended to when differentiating /k/ from /t/ in the perceptual domain. We do not know the topography of the child’s articulatory gestures when producing the contrast given that the primary data in the paper is phonetic transcription. In our book Françoise and I describe cases like McAllister Byun’s who received “motor oriented therapy” and failed to make measurable progress in therapy over three years! My interpretation of this case is that the child was probably attending to the formant frequency transitions in perception which results in erratic perceptual performance in both onset and coda. Productively the child may manipulate the timing of the release of the undifferentiated lingual gesture so as to produce [t] in the onset but a perceptually accurate but phonetically inaccurate [k] in the coda. His phonetic knowledge of the contrast is incomplete in the perceptual and articulatory domains in both onset and the coda. The treatment program needs to address his perceptual, articulatory and phonological knowledge of the /k/ phoneme. SLPs, not having access to EPG and speech synthesizers and other research tools for precisely mapping the child’s phonetic knowledge at all levels of phonological representation, can only guess as to the status of the child’s knowledge in these domains. The safest assumption is that the child’s knowledge is incomplete at all levels and the most prudent course of action is to address all three. Your therapy will be more effective and efficient in the long run.

Readings

Dorman, M., M. Studdert-Kennedy, et al. (1977). “Stop-consonant recognition: Release bursts and formant transitions as functionally equivalent, context-dependent cues.” Attention, Perception, & Psychophysics 22(2): 109-122. http://www.springerlink.com/content/8583238315777761/

Forrest, K., G. Weismer, et al. (1990). “Statistical analysis of word-initial /k/ and /t/ produced by normal and phonologically disordered children.” Clinical Linguistics & Phonetics 4(4): 327-340. http://informahealthcare.com/doi/abs/10.3109/02699209008985495

Gibbon, F. E. (1999). “Undifferentiated lingual gestures in children with articulation/phonological disorders.” Journal of Speech, Language, and Hearing Research 42: 382-397. http://bit.ly/Nj4VIf

Gibbon, F. and S. E. Wood (2002). “Articulatory drift in the speech of children with articulation and phonological disorders.” Perceptual and Motor Skills 95: 295-307.

Jamieson, D. G. and S. Rvachew (1992). “Remediation of speech production errors with sound identification training.” Journal of Speech-Language Pathology and Audiology 16: 201-210.[OPEN ACCESS]

http://www.caslpa.ca/english/resources/database/files/1992_JSLPA_Vol_16/No_03_177-250/Jamieson_Rvachew_JSLPA_1992.pdf

McAllister Byun, T. (2012). “Bidirectional perception–production relations in phonological development: evidence from positional neutralization.” Clinical Linguistics & Phonetics 26(5): 397-413.

http://informahealthcare.com/doi/abs/10.3109/02699206.2011.641060

Nguyen, V. S., E. Castelli, et al. (2009). Vietnamese final stop consonants /p, t, k/ described in terms of formant transition slopes. 2009 International Conference on Asian Language Processing: Recent Advances in Asian Language Processing, IALP 2009. Singapore: 86-90. [OPEN ACCESS

http://tainguyenso.vnu.edu.vn/xmlui/bitstream/handle/123456789/13274/HN_U377.pdf?sequence=1

Munson, B., J. Edwards, et al. (2010). “Deconstructing phonetic transcription: Covert contrast, perceptual bias, and an extraterrestrial view of Vox Humana.” Clinical Linguistics & Phonetics 24: 245-260. http://informahealthcare.com/doi/abs/10.3109/02699200903532524

Redford, M. A. and R. L. Diehl (1999). “The relative perceptual distinctiveness of initial and final consonants in CVC syllables.” The Journal of the Acoustical Society of America 106(3): 1555-1565. http://asadl.org/jasa/resource/1/jasman/v106/i3/p1555_s1

Rvachew, S. (1994). “Speech perception training can facilitate sound production learning.” Journal of Speech and Hearing Research 37: 347-357. http://bit.ly/Qt0Piv

Rvachew, S. (2006). “Longitudinal prediction of implicit phonological awareness skills.” American Journal of Speech-Language Pathology 15: 165-176. http://bit.ly/RMcfMZ

Rvachew, S. and F. Brosseau-Lapré (2012). Developmental Phonological Disorders: Foundations of Clinical Practice. San Diego, CA, Plural Publishing, Inc. http://bit.ly/vIliz2

Rvachew, S. and M. Grawburg (2006). “Correlates of phonological awareness in preschoolers with speech sound disorders.” Journal of Speech, Language, and Hearing Research 49: 74-87. http://bit.ly/RsQ2ER

Shiller, D. M., S. Rvachew, et al. (2010). “Importance of the auditory perceptual target to the achievement of speech production accuracy.” Canadian Journal of Speech-Language Pathology and Audiology 34: 181-192. (http://bit.ly/PSlmXk)

On Target Practice and Speech Therapy

Research Digest (http://bps-research-digest.blogspot.ca/2012/08/targets-look-bigger-after-shot-that.html ) posted a rather curious article about the relationship between perceived target size and shooting accuracy. In the context of archery, larger targets are easier to hit; at the same time, when the target is successfully hit the archer retrospectively perceives the target to be bigger than it was. Apparently this works for golf too in the context of putting and perceived cup size. The authors of the golf research suggest a reciprocal relationship between perception and performance. I don’t recall ever noticing the retrospective relationship in my own life but I do know that prospective perception of the target is a critical factor and that my golf game has always been hampered by poor representation of target location. It is very annoying how often my husband tells me “that ball went right where you aimed it” just as it is disappearing into the forest far from what I thought was my target.

Last week I spent more time in the lab watching some of the 1000 hours of video we recorded as part of the ECRIP trial (Essai Clinique Randomisé sur les Interventions Phonologiques; a randomized control trial of phonological interventions for francophone children). It was a great pleasure to watch one of our most talented students teaching two delightful children to articulate the /ʃ/ phoneme using one of the more popular games in the Output Oriented treatment arm. The game is called ‘course des animaux” (animal race): it provides opportunities to practice animal names that include the /ʃ/ phoneme in different word positions such as “chat” (cat) → [ʃa], “cheval” (horse) → [ʃəval], “cochon” (pig) → [kɔʃɔn], and “vache” (cow) → [vaʃ]. One child in particular was having a lot of trouble with “vache”, producing [vas] or [ʃvas] on each spontaneous trial although achieving it with pictogram support to help him sequence the head and coda of the word appropriately. The student clinician was providing excellent feedback and prompting the child to use the pictographic cues at appropriate intervals. What was clear from the child’s face however is that he had no idea of the target; he had to look to the student clinician on each trial to verify if he had achieved it. Whether he said [vas] or [vaʃ] he would produce the trial with the same frown of concentration and then look to the clinician for feedback; if she indicated that he had produced the word with “un beau rond” (a good circle), only then would he break into a smile. Even more interesting, another student arrived in the lab while we were watching the video and informed us that this child was related to her and that he was still misarticulating “vache” in spontaneous conversation, now two years after the videorecorded therapy session (it takes us a long time to analyze our data!).

We can contrast this exchange with another one that is reproduced (as a hypothetical English version of the original French session) in Chapter 9 of Developmental Phonological Disorders: Foundations of Clinical Practice. The exchange involves a child who was assigned to the Input Oriented treatment arm of the ECRIP trial. All the Input Oriented treatment procedures were directed at strengthening the child’s acoustic-phonetic or underlying phonological representations of the target form. The sessions are markedly different from those conducted in the Output Oriented intervention in which the child is practicing speech all the time; in the Input Oriented sessions the focus is on the therapist providing input while the child listens. The procedures that were used in the Input Oriented intervention were as follows: In the first session the student therapist would identify the target for the child. Then the therapist would proceed to auditory bombardment in a meaningful context such as a story. For example, when /ʃ/ was the target, Michel, le mouton qui n’avait pas de chance (Sylvain Victor)was a favourite for our student therapists to read since it is a delightful story that provides at least one /ʃ/ exemplar approximately every three seconds of reading. Auditory bombardment would be followed by activities in which the child actively judged words to be correctly or incorrectly pronounced. This is the specific exchange that I want to contrast with the “course des animaux” activity. Rather than asking the child to name animals as they participated in a race to the farm, the therapist essentially asks the child’s permission to put the animals in the barn – he has control of the animals but they cannot go in unless the therapist pronounces the words correctly. While he holds the horse, she says to the child “J’aimerais faire entrer le [sival] (I would like to make enter/let in the horse (pronounced incorrectly)”. The child tells her he won’t let in the horse because she must say it “like it should be said”. So she tries again, “J’aimerais faire entrer le [səval]”. Now the child gets impatient. He explains that he can’t let in the horse unless she says [ʃəval]. “Oh”, exclaims the therapist, “J’aimerais faire entrer le [ʃəval]”. Without wasting any time the child gallops the horse into the barn. At this moment the child has shown us that he has achieved perceptual and productive knowledge of the target form. Now we know that he is ready to progress to expressive minimal pairs therapy activities and the focus will switch to speech production activities. Up until this time there has been no explicit expectation that the child produce speech unless he wished to. If the child attempted a target word the therapist would respond with recasts, imitations and expansions but no explicit information about the child’s production accuracy. We haven’t finished our data analysis yet but we know that the Input Oriented intervention was at least as effective as the Output Oriented intervention on our single word picture naming test even though the children in this treatment arm received very little direct speech practice during their therapy sessions. Our preliminary results mirror those reported by Hesketh and colleagues in which they found that standard articulation therapy and a phonological awareness intervention had similar outcomes in the short-term but the phonological awareness program appeared to provide a better basis for spontaneous generalization by the children over the long term (http://onlinelibrary.wiley.com/doi/10.1080/136828200410618/abstract).

We think that Input Oriented therapy has the advantage, for all children, of providing them with a clear sense of the target so that they can determine for themselves whether they are achieving it or not. Children who receive standard articulation therapy tend to be very reliant on their therapist for information about their own speech accuracy which deprives them of hours of speech practice every day. Children who know what the target is can practice independently. This approach to therapy is also especially appropriate for children who cannot or will not engage in structured speech therapy activities due to their age or cognitive level or temperament. Finally we found that it was an excellent choice for children who had “bottomed out” with standard therapy and were in no mood to continue cooperating with speech practice after a long period of failure to succeed with a given target.

Francoise and I will teach a workshop at ASHA this year on how to implement Input Oriented therapy.

Topic Area: Speech Sound Disorders in Children (SLP)
Session Number: 1420

Title: Input-Oriented Approaches to Intervention for Children With Developmental Phonological Disorders

Session Format: Oral Session (Seminar 2-Hours)
Day/Time: Saturday, Nov 17 — 08:00 AM – 10:00 AM

Authors: Francoise Brosseau-Lapre, McGill U; Susan Rvachew, McGill U

On Golf and Speech Therapy

Last weekend I didn’t write a blog post because the weather was spectacular and I was having too much fun enjoying the new deck at my cabin and playing golf. This weekend it is raining so I have plenty of time to reflect on the decline in my golf skills since I gave it up three years ago to devote my weekends to writing a book. My daughter says I should go get a lesson but I am too embarrassed to do that because I am in such poor physical shape. I am not convinced it would help in any case because my husband and I used to go get tune up lessons in the spring and I was never convinced that these were a good investment. The instructors would give me a bucket of balls and leave me by myself while concentrating on my husband. This used to annoy me no end – I thought it was some sort of sex discrimination thing until I complained one time and the instructor says, “no, no – you really don’t need my help, you have a perfect swing, just keep practicing as you are”. Imagine my surprise! If I had a perfect swing, why was my score so awful (even before I gave up golf to write a book my scores were pretty awful but I had a terrific 200 yard drive so my score didn’t bother me so much). Anyway, when I was writing chapter three, I had to study up on theories of speech motor control and I figured out why my perfect swing wasn’t much good to me.

Practice Conditions

The problem is related to the vast difference in the practice conditions for golf relative to the actual playing conditions. Golf lessons and most practice sessions occur at a driving range or a golf dome as illustrated here: the terrain is perfectly flat and the practice mats are positioned to ensure that your body is aligned square to the target line. During practice it is common to hit many balls with the same club, concentrating on executing the same motor plan with a high degree of precision.

Play Conditions

Play Conditions

Our playing conditions are vastly different since our cabin is located 5 minutes from a course where, for $1500 a year the whole family can play as often as we have time for, with carts and no tee times – just show up and play nine holes when we feel like it, it’s wonderful. There is a hitch though and that is that it’s pretty much the worse golf course in the world except for the scenery. There isn’t a flat spot on it and that includes the tee boxes. Every time you hit your ball you are likely to end up with a bad lie like this one (ball below feet, basically hitting off gravel). All the precision in the world with my perfect swing is not going to help me hit this ball. What I need to do is process the initial conditions accurately and select a motor plan that is going to get the club to the ball given those conditions. Looking at the picture I can tell that my ball is too far back in my stance but at the time I was quite unaware that I had positioned myself incorrectly relative to the ball – often my problem is one of poor information processing that leads me to essentially select the wrong initial conditions for the purpose of predicting which motor plan will have the desired effect.  Poor execution of my swing is not the problem. Unfortunately when I achieve the inevitable bad result I start to adjust my swing which just makes everything worse. Instead, I need to focus on processing aspects of the context so that I can adapt my set-up to the initial conditions: First, what is the gradient of the slope between my feet and the ball? How much of an incline is there in the lie of the ball? Where is the target relative to the ball? And then, where are my feet relative to the ball? How wide is my stance? How bent are my knees? Where is my centre of gravity? Are my shoulders aligned with the slope of the hill?

So what has golf got to do with speech therapy? Given that speech is also a motor learning problem, the same principles of motor learning that apply to golf apply to speech learning. I have spent a bit of time this summer watching therapy videos as part of the treatment fidelity process in the randomized control trial that Françoise and I recently completed. I see student clinicians and sometimes the experienced SLPs conducting therapy sessions like practice at the golf dome – aiming for precision rather than dynamic stability. I think the students should know better because I taught them the principles of motor learning using Maas et al.’s (2008) excellent Tutorial http://bit.ly/Ta9STv in which the authors stress the distinction between learning and performance. Performance during practice may or may not transfer to untrained movements in nonpractice contexts. Maas et al. discuss a number of different strategies to enhance transfer of training to similar but unpracticed movements. Although the research findings are complex and often difficult to interpret, it appears that overall it is best to practice under conditions that afford a wide range of experience with varying initial conditions and movement outcomes. At the golf dome the best one can do is switch clubs and targets often. In speech therapy, practicing the target phoneme in many different words so as to vary phonetic context is often a good strategy. I think that novice and experienced SLPs know that variable practice conditions are important but it is not always easy to implement this principle for two reasons. The first is that performance levels are higher under constant than variable practice conditions and it is reinforcing to both clinician and patient to achieve high levels of accuracy during therapy sessions (the distinction between practice performance and actual learning is hard to keep in mind). The second is more fundamental: the goal of the therapy exercise is not itself clear to SLP or patient. In some ways, Maas et al.’s Tutorial contributes to this confusion of aims by focusing on motor programming and motor programs. Therapy sessions are conducted as if the goal is to perfect the specification and execution of a particular motor program. I prefer Wolpert’s approach to motor learning http://bit.ly/OE8VT5 (take a look at this if only for the Calvin and Hobbe’s cartoons). Wolpert and colleagues (2001) describe motor control “as the process of transforming sensory inputs into consequent motor outputs. The problem of motor learning is one of mastering and adapting such sensorimotor transformations” (p.488). We can think of speech therapy as the process of helping the patient to process the sensory input so as to transform them into the desired motor outputs. An approach to motor learning that takes into account information theory and information processing is the “challenge point framework”, described by Guadagnoli, M. A. and T. D. Lee (2004) http://www.tandfonline.com/doi/abs/10.3200/JMBR.36.2.212-224#preview. Françoise and I are going to teach a seminar about how to apply this framework to speech therapy at ASHA 2012 in Atlanta this fall:

Topic Area: Speech Sound Disorders in Children (SLP)
Session Number: 1530

Title: Application of the Challenge Point Concept to Developmental Phonological Disorders

Session Format: Oral Session (Seminar 2-Hours)
Day/Time: Saturday, Nov 17 — 03:00 PM – 05:00 PM

Authors: Susan Rvachew, McGill U; Francoise Brosseau-Lapre, McGill U

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