Phonology Assessment in SLP Private Practice

I am continuing with a series of blogs about private practice speech-language pathology. Fortunately many new clinicians can join an established practice and won’t have to think about these things. More frequently however young SLPs are setting up their own practice right out of school or very early on, in their home during their maternity leave for example. The focus of this blog is an aspect of setting up your practice that I am not seeing much advice about in other blogs (maybe I missed blogs about this, please write with links if I have). There other excellent blogs on setting up a private practice, for example 5 Key Steps to Start a Speech Therapy Private Practice (speechbuddy.com). ASHA also has a site the links to many key resources on the topics including ethics issues and quality indicators for your practice: Private Practice in Speech-Language Pathology (asha.org). I recommend these sources, but I am going to fill in a small but critical gap and that is the necessity of having the appropriate assessment materials on hand before you begin. And because you must obtain proper copyright to the materials or buy them (do not borrow them from your other employer!), I will provide some costing information.  In the last blog I talked about the importance of expertise and specializing in those clients you are most qualified to serve. Therefore, I will focus on speech sound disorders in children aged approximately 3 through 8 years.

The need to have assessment materials should be obvious. The practice guidelines world-wide indicate that your treatment goals and plans must be based on the results of a comprehensive assessment. Often times I see SLPs trying to select goals and treatment methods without having the results of a comprehensive assessment to guide their choices. How does this happen? There are so many reasons, almost too many to count but a few of them are unique to the private practice environment. Clients may not want to pay for the time it takes to assess when they are so desperate for treatment and their insurance may cover only 6 sessions. And the SLP may not want to pay for assessment materials when they are so expensive and observation can be valuable. Free observation is not a substitute for systematic assessment and analysis of the data in any circumstance. In the next blog I will demonstrate all the ways that superficial observations can be misinterpreted or at least differently interpreted. Even if the data is a detailed speech sample, a transcription and phonological analysis will be required. So which assessment tools are minimally required? Francoise and I developed a rubric for this, shown as Figure 5-1 in our DPD text and Figure 3-2 in our IntroSSD text. I will show the types of assessments in the table below, including those that are mandatory and those that are optional* and suggest options for each with free and commercial sources indicated.

ConstructPossible TestSource
Contextual factorsCase historyDPD text Publications :: Plural Publishing
Articulation accuracyDEAP Articulation TestDiagnostic Evaluation of Articulation and Phonology (DEAP) (pearsonclinical.ca)
StimulabilityDEAP or informalInformal is fine
Oral-motor screenDEAP or other publishede.g., DPD has 3
Speech accuracy in continuous speechReference data for Percent Consonants Correct) Shriberg et al.Reproduced in DPD or see Austin & Shriberg (1997)
Hearing acuityHearing screeningFree apps: HearScreen — THE AUDIOLOGY PROJECT
Phonology*DEAP or hand scored from conversational sampleSee above or DPD
Word Inconsistency*DEAPSee above
IntelligibilityIntelligibility in Context ScaleOverview – Multilingual Children’s Speech (csu.edu.au)
Speech Perception*Speech-Production Perception Task or SAILSFree procedure in DPD or see http://www.dialSpeech.com
Phonological Awareness*Phonological Awareness Test (implicit)Free with norms in DPD
Nonword Repetition*Syllable Repetition TaskOverview – The Phonology Project – UW–Madison (wisc.edu)
Language screene.g., QUILS (3 to 5 yrs) or SPELT (4 to 9 yrs) Or story retell with SALTLanguage Screening Tools – QUILS (quilscreener.com)
SALT Home Page (saltsoftware.com)
Intelligence screen*Kaufman Brief Intelligence TestClinical Assessment Canada – English (pearsonclinical.ca)

This list of required test materials looks lengthy but the ultimate cost is quite moderate. Instructions and normative data for the case history, the oral-peripheral examination, articulation and phonological analysis for toddlers through school age children (with normative expectations), speech perception testing and an implicit awareness test are all tucked inside the DPD text which can be obtained for $150.00. Measures of intelligibility, a hearing screener, and the syllable repetition task are available free on the internet. You should have a standardized measure of articulation and/or phonology. I like the DEAP because it is comprehensive with good diagnostic properties; it costs about $600 with test forms. You can measure expressive language abilities informally although it is time consuming to do so. For younger children the QUILS receptive language screener is only $100. Generally standardized tests are in the $300 to $600 range unfortunately.

You might question the value of the optional tests, especially the K-BIT. However, I strongly recommend having the Kaufman Brief Intelligence Test because it includes a receptive vocabulary test as the verbal IQ screen and a nonverbal IQ screen and often you need a little bit of extra information to justify referring children to a psychologist. I have struggled to achieve progress with quite a few preschoolers in my practice who turned out to have very significant but undiscovered cognitive delays. The K-BIT is sold by Pearson for about $500. For children younger than four a play skills assessment can be a good substitute.

So, not worrying about exchange rates and rounding around the edges, you can count on spending $1500 on assessment materials in your first year. You should count on spending that much every year in order to update your editions and add tests in areas not covered by this stripped down list. After you add your provincial and federal association fees and your malpractice and liability insurance you are still not paying very much to start charging people for your services. The real costs come with actually conducting and then scoring the tests, and in phonology, analyzing the data. However, that is the competence that your clients are paying you for. More about that in the next post.

Speech Therapy and Speech Motor Control: Part 3

In two previous blogs I discussed a recent paper by Strand in which she outlines in detail the theoretical foundation and procedural details of Dynamic Temporal and Tactile Cueing (DTTC) as a treatment for Childhood Apraxia of Speech (CAS). In Part 1 I suggested that the theoretical base, being Schmidt’s “Schema Theory of Discrete Motor Skill Learning,” was outdated. In Part 2 I discussed modern theories of speech motor control that assume a dynamic interplay of feedforward and feedback control mechanisms. In this blog I will discuss the implications for speech therapy, in relation to critical aspects of DTTC.

First, let us consider the core element of DTTC, “the focus on the movement (rather than the sound or phoneme) in terms of modeling, cueing, feedback, and target selection” (p. 4). I believe that all of us who strive to help children with CAS acquire intelligible speech agree that speech movements are the focus of speech therapy, as opposed to phonological contrasts. Nonetheless, this statement raises questions about the nature of “speech movements.” What is the goal of a speech movement? The answer to this question is controversial: it may be a somatosensory target involving specific articulators, such as for example bring the margins of the tongue blade into contact with the upper first molars; or it may be to produce a particular vocal tract shape such as a large back cavity separated from a small front cavity by a narrow constriction; or it may be to produce an acoustic output that will be perceived as the vowel [i]. The DTTC is structured to promote precise and consistent movements of the articulators and therefore the first scenario is presumed. Furthermore, the origin of CAS is hypothesized to be a deficit in proprioceptive processing that arises from an impairment in cerebellar mechanisms. Updating the theory, this hypothesis would implicate feedforward control which, following from Guenther and Vladosich (2012), “projects directly from the speech sound map [in left ventral premotor cortex and posterior Broca’s area] to articulatory control units in cerebellum and primary motor cortex” (p. 2). However, new research (Liégeois et al., 2019) identifies the locus of structural and functional impairments underlying CAS as being along a dorsal pathway of cortical structures, specifically: reduced white matter and fMRI activations in sensory motor cortex and along the arcuate fasciculus and reduced grey matter and fMRI activations in superior temporal gyrus and angular gyrus. They explain that “this route links auditory input/representation to articulatory systems … and transforms phonological representations into motor programs …In contrast, the speech execution white matter pathway (corticobulbar) and the ventral language route (IFOF) were not altered in this family” [that showed multigenerational impairments in speech praxis]. My point is that although the cerebellum is important to speech motor control and CAS may well involve impairments in proprioceptive feedback, speech is clearly a sensory motor skill that requires close connection among articulatory and auditory representations for sounds and syllables.

In Part 2 of this blog series I indicated that adults can compensate for unexpected perturbations to articulatory trajectories or auditory feedback very rapidly by drawing on their internal model of vocal tract function. It is interesting to consider that throughout speech development children cope with perturbations to articulatory gestures and expected acoustic outputs because their vocal tract is changing shape, sometimes quite dramatically, throughout childhood. Callen et al. (2000) showed how the developing child can adapt to the changing vocal tract by aiming for relatively stable auditory targets (conceived of as regions in auditory space) and using auditory feedback and simulations of auditory outputs to achieve those targets even as vocal tract structure is changing. The key to this remarkable ability is a learned mapping between articulator movements, vocal tract shapes and auditory outputs. The learning and updating of this internal model of vocal tract function arises from an unsupervised learning mechanism, essentially Hebbian learning: young infants engage in a great deal of unstructured vocal play as well as somewhat more structured babbling – speech practice that allows them to learn the necessary correspondences without having specific speech goals. Infants with CAS are widely believed to skip this period of speech development; therefore, it is likely they begin speech therapy without an internal model of vocal tract function which is foundational for goal directed speech practice. Therefore, precise, repeated, consistent speech movements may not be the best place to start a treatment program for severe CAS; a program of unstructured vocal play that targets highly varied playful vocalizations is a better starting place for many children. Subsequently, high intensity practice with babble (repetitive syllable production) will stabilize the mappings between articulatory gestures and the resulting vocal tract configurations and somatosensory and auditory outcomes.

One of the advantages of a well-tuned internal model of vocal tract function is that it supports “motor-equivalent speech production” given commonly occurring constraints on speech production. In other words, there are many different articulatory gestures that will produce the same acoustic-phonetic goal. When the child has a stable acoustic-phonetic target and is able to process auditory feedback in relation to that target, various articulatory solutions can be found to adapt to changing vocal tract structure or constraints such as talking while eating or a holding a pen between the teeth. Developmental changes in the way that articulators are coordinated to produce the same phoneme are well documented in the literature. Similarly speech production varies with phonetic context. Motor equivalent trading relations between tongue body height and lip rounding are well known for production of the vowel [u] and the consonant [ʃ] for example and the front-back positioning of the constriction in these phonemes is highly variable across speakers and phonetic contexts. The precision with which these phonemes are produced is related to the talker’s perceptual acuity: for example, adults who have sharp perceptual boundaries between [ʃ] and [s] produce them with greater articulatory consistency as well as greater acoustic contrast between the phoneme categories. Perkell et al. (2004) speculated “In learning to maximize intelligibility, the child with higher acuity is better able to reject poor exemplars of each phoneme (as in the DIVA model), and thus will adopt sensory goals for producing those phonemes that are further apart than the child with lower acuity.” The implications for speech therapy are that, even in the case of CAS, ensuring stable acoustic-phonetic targets for speech therapy goals is essential whereas insisting upon SLP defined articulatory parameters may be counter-productive. The goal is not absolute  consistency in the production of specific motor movements, but rather, dynamic stability in the achievement of speaking goals.

Although it is speculated that feedforward control is weighted more heavily than feedback control in adult speech, feedback is critical to speech learning during infancy and childhood. Furthermore, auditory feedback plays a crucial role. The initial goal is an auditory target. Guenther and Vladusich (2012) explain that “the auditory feedback control subsystem [helps to] shape the ongoing attempt to produce the sound by transforming auditory errors into corrective motor commands via the feedback control map in right ventral premotor cortex” (p. 2). They further explain that repeated practice of this type eventually leads to the development of somatosensory goal regions. A particular frustration for children with CAS is perseveration, the difficulty of changing a well-learned articulatory pattern to a new one that is more appropriate. This problem with perseveration highlights the need to engage the feedback control system. There are two strategies that are essential: first a high degree of variation in the practice materials which can be introduced by practicing nonsense syllables with a carefully graded increase in difficulty but variation in the combination of syllables within difficulty levels. The second strategy is to provide just the right amount of scaffolding along the integral stimulation hierarchy so that the child will be successful more often than not while experiencing a certain amount of error. Some error ensures that corrective motor commands will be generated from time to time. Imagine practicing syllables that combine four consonants [b, m, w, f] with four vowels [i], [u], [æ], [ɑ] and four diphthongs [ei], [ou], [ɑi], [au], [oi], presented at random so that the child imitates the first syllable (Say [bi]) and then repeats it again twice (Say it again… and again…), before proceeding to another syllable. You will have a great many targets in your session but created from a small number of elements. Imagine further that you progress to a more difficult level (reduplicated syllables, [bubu], [mimi]) as soon as the child achieves 80% correct production of the single syllables. You can see that you will also be allowing the child to produce quite a bit of error. We call this the challenge point. Tanya Matthews, Francoise Brosseau-Lapré and I are working on a paper to describe how to do this and describe our experiences with the approach. You will see that it is very different from working on five words and requiring that the child achieve 15 to 20 correct productions at the imitative word level before proceeding to delayed imitation and then again before proceeding to spontaneous productions. Errorless learning is a fundamental aspect of DTTC and has a long history in speech therapy practice. However it is not clear that it is well-motivated from the perspective of developmental science.

To summarize, there are many aspects of DTTC that are similar across all sensory-motor approaches to the treatment of CAS. In particular high intensity speech practice is well motivated and likely to be effective with all forms of moderate and severe speech sound disorder. Nonetheless there are some significant differences between Strand’s approach and the approach that I recommend based on an updated theory of speech motor control. There is still a great deal of research to do because very few of our specific speech therapy practices have received empirical validation even though speech therapy in general has been shown to be efficacious. As a guide to future research (hopefully using randomized and thus interpretable designs), I provide a table of procedures that are similar and different across the two theoretical approaches.

 

SCHEMA THEORY

AUDITORY FEEDBACK CONTROL

Treatment Procedures that are Similar

High intensity practice
Focus on speech movements (not phonemes)
Practice syllable sized units (not isolated sounds)
Attend to temporal aspects of trial structure (delayed imitation, delayed provision of feedback)
Integral stimulation hierarchy (attend to visual and auditory aspects of target)

Treatment Procedures that are Different

Focus on precise, consistent movements Focus on dynamic stability
Over-practice: accuracy over 10-20 trials Variable practice when possible
Errorless learning Challenge point: 4/5 correct, then move up
Behavioral shaping of accurate movements Motor equivalent movements
Tactile and gestural cues to ensure accuracy Sharpen knowledge of auditory target
“Hold” initial configurations Encourage vocal play, develop internal model

Readings:

Callan, D. E., Kent, R. D., Guenther, F. H., & Vorperian, H. K. (2000). An auditory-feedback-based neural network model of speech production that is robust to developmental changes in the size and shape of the articulatory system. Journal of Speech, Language, and Hearing Research, 43, 721-738.

Guenther, F. H., & Vladusich, T. (2012). A neural theory of speech acquisition and production. Journal of Neurolinguistics, 25(5), 408-422.

Liégeois, F. J., Turner, S. J., Mayes, A., Bonthrone, A. F., Boys, A., Smith, L., . . . Morgan, A. T. (2019). Dorsal language stream anomalies in an inherited speech disorder. Brain, 142(4), 966-977.

Perkell, J., Matthies, M., Lane, H., Guenther, F. H., Wilhelms-Tricarico, R., Wozniak, J., & Guiod, P. (1997). Speech motor control: Acoustic goals, saturation effects, auditory feedback and internal models. Speech Communication, 22, 227-250.

Perkell, J., Matthies, M. L., Tiede, M., Lane, H., Zandipour, M., Marrone, M., . . . Guenther, F. H. (2004). The distinctness of speakers’ /s/-/ʃ/ contrast is related to their auditory discrimination and use of an articulatory saturation effect. Journal of Speech, Language, and Hearing Research, 47, 1259-1269.

Rvachew, S., & Matthews, T. (2017). Demonstrating treatment efficacy using the single subject randomization design: A tutorial and demonstration. Journal of Communication Disorders, 67, 1-13.

Rvachew, S., & Matthews, T. (2019). An N-of-1 Randomized Controlled Trial of Interventions for Children With Inconsistent Speech Sound Errors. Journal of Speech, Language, and Hearing Research, 62, 3183–3203

Speech Therapy and Speech Motor Control: Part 2

Speech Therapy and Theories of Speech Motor Control: Part 2

In Part 1 of this blog series I described the theoretical basis of Dynamic Temporal and Tactile Cueing as recently published by Edy Strand. Specifically, the treatment is founded on Schmidt’s Schema Theory in which generalized motor programs are learned. During speech production the child must select the right program and apply the correct parameters before implementing it all at once. If the parameters are selected incorrectly, a speech error will occur. It is rather like making toast. If you forget to reset your settings after toasting bagels, your Wonderbread will come out black! The problem as stated by Schmidt is that by the time you realize that your toast settings are wrong and your motor gestures are off track, it’s too late— the toast is burned and you have said “Trat! Doast!” Learning occurs by “trial and error” — after much experience with your toaster you learn the settings (parameters) for getting the right amount of toastiness for different items. Learning to operate your toaster is similar to acquiring one “generalized motor program.” Speech motor learning is assumed to operate this way because sensory feedback is too slow to support on-line adjustments to the parameters in a direct way. I used a different analogy in the previous blog — once you have committed to swinging your golf club, you tend to follow through.

The problem with this model of speech motor control is that we know for certain that real time modification of vocal tract movements occurs in response to somatosensory and auditory feedback. Strangely we have known since the early eighties that the speech system is highly sensitive to error on-line; therefore, I don’t know why this idea of open-loop control persists. The proof comes from studies in which (typically) an adult is asked to repeatedly produce a particular syllable or disyllable and then experiences a perturbation in sensory feedback (either somatosensory feedback or auditory feedback). An early example of this paradigm involved productions of “aba”: during 15% of trials a mechanism placed an unexpected load on the talker’s lower lip. Here is where it gets interesting: the research participants corrected for this perturbation in the articulatory trajectory of the bottom lip very rapidly with compensatory actions of the top and the bottom lip (the bottom lip would need to exert greater upward force and the top lip would need to produce greater downward extent in order to produce the labial closure and the expected transitions into and out of the consonantal closure). Decades of experiments have followed involving many other perturbations in the domain of articulatory gestures, somatosensory (skin) sensations, and auditory feedback. For example, while the research participants are repeatedly saying “bed” you can trick their ear into thinking they are saying “bad” which leads to compensatory adjustments in articulation to get the expected auditory percept.

This kind of dynamic compensation across the entire vocal tract is made possible by an “internal model” — a neural model that simulates the behavior of a sensorimotor system in relation to its environment. The internal model can generate a prediction of the sensory consequences of implementing a motor plan via simulation. For speech, future outputs in the somatosensory and auditory domains are simulated; furthermore, the simulator takes into account delayed sensory feedback, noise in the perceptual system and other variables so that when feedback arrives it can be compared with the prediction and provide reliable error messages. Continuous tracking of the vocal tract state is thus permitted and forms the basis for ongoing planning of movements as speech unfolds. If an unexpected event occurs, as in the perturbation experiments that I have described, error corrections are dynamic across the entire system; therefore, if the predicted trajectory of acoustic formant transitions from the [a] into the [b] closure is not occurring, lower lip, upper lip, jaw and tongue movements can all be harnessed to produce the desired outcome.

As Houde and Nagarajan (2011) explain, “speech motor control is not an example of pure feedback control or feedforward control” (p. 11). The acquisition of speech motor control is dependent upon the development of the internal model of vocal tract function as well as detailed knowledge of auditory targets. This understanding has implications for the treatment of childhood apraxia of speech. I will explore these implications further in the next and final blog in this series.

Readings

Abbs, J. H., & Gracco, V. L. (1983). Sensorimotor actions in the control of multi-movement speech gestures. Trends in Neurosciences, 6, 391-395.

Houde, J. F., & Jordan, M. I. (2002). Sensorimotor adaptation of speech I: Compensation and adaptation. Journal of Speech, Language & Hearing Research, 45(2), 295-310.

Houde, J. F., & Nagarajan, S. S. (2011). Speech production as state feedback control. Frontiers in Human Neuroscience, 5, doi: 10.3389/fnhum.2011.00082.

Tourville, J. A., Reilly, K. J., & Guenther, F. H. (2008). Neural mechanisms underlying auditory feedback control of speech. NeuroImage, 39, 1429-1443.

Speech Therapy and Theories of Speech Motor Control: Part I

Edy Strand recently published a detailed description of her Dynamic Temporal and Tactile Cueing treatment strategy. As she says this is a hugely valuable paper because it provides a complete description of a treatment designed for severe speech sound disorders, especially Childhood Apraxia of Speech, and more importantly, it summarizes in one place the theoretical foundation for the treatment. I think that, on the whole, this is an efficacious treatment although there are some procedures, derived directly from the outdated theoretical underpinnings, that are questionable however, and therefore I am going to devote several blogs to more recent theory and basic science research on the development of speech motor control and apraxia of speech. In this first blog, I review Schema Theory, even though this theory is just not right! But it has a long history and remains currently popular across almost all clinically-oriented papers on motor speech disorders.

The theory that is referenced in Edy Strand’s paper is Richard Schmidt’s “Schema Theory of Discrete Motor Skill Learning,” published in Psychological Review in 1975 and subsequently brought to speech-language pathology by Ray Kent and others as a useful framework for thinking about speech therapy. The important idea underlying this theory is that motor skills are made up of brief, discrete motor acts that are executed all-at-once as open-loop generalized motor programs, adapted with specific response specifications (called parameters) for the current conditions. The theory assumes “open-loop” control because sensory feedback is often too slow to impact movement after it has started. According to this theory feedback is processed after the movement is over and incorporated into the schema for the future execution of the generalized motor program. I have used golf as an example before; even though I haven’t played much in years let’s do it again: if we are adopting this theory we would think of practice sessions as developing different generalized motor programs for each type of shot, a long drive, a short 7-iron shot, the up-and-down pitch onto the green, and the putt into the hole. Which shot you choose depends upon your recall schema: what is your target and which type of shot is likely to achieve it? I personally recall that when close to the green my pitch is better than my chip (whereas my husband has the opposite preference). How you address the ball depends upon the initial conditions (flat ground, hill, tall grass etc.). The motor control parameters (also known as response specifications) depend upon the distance to the target (how high to lift the club, speed of follow through, force applied and so on). Based on the initial conditions and the desired outcome, I launch the shot with my wedge, expecting a certain “feel” as I hit the ball based on past experience with the sensory consequences of hitting this shot; I can always “recognize” a good hit even before I see the ball land (often I just turn my back on the ball, I don’t even want to see it land!). But in any case, the actual outcome is important for updating the “recall” schema; specifically, if I have actually achieved my target, I add all this information, the initial conditions, the response specifications, the recognition schema and the recall schema to my memory. The generalized motor program is an abstraction across all these remembered practice trials, permitting correct specification of the response parameters in future shots. Furthermore, I should be able to adapt the generalized motor program to similar shots, even if the ball is a little further or closer to the green for example.

When applied to CAS, in which current research suggests unreliable or degraded somatosensory feedback, the use of this model focuses attention on the child’s processing of initial conditions, inaccurate planning or programming of the movement due to poor selection of response specifications, and/or poor recognition schema (not knowing when the movement “feels right”). Therefore, certain procedures are recommended. DTTC providers use manual or gestural cues to shape the child’s articulators into the “initial position” and encourage the child to “hold” the position momentarily so as to fully process those initial conditions before launching the movement. During the initial stages of therapy, the SLP uses a slow rate and co-production so that the child is getting extra feedback during the practice trial, presumably with the goal of stabilizing the recognition schema. Imitative models support the child’s knowledge of the target which, when combined with copious knowledge of results feedback should support the development of recall schema. And finally, a great deal of practice with an errorless approach ensures that the child lays down many memory traces of correctly executed motor programs.

The recommendations that are provided make a certain amount of sense given the context of schema theory (even though there is in fact no evidence for the specific efficacy any one of these particular procedures). The problem is that it is not clear that schema theory is a reasonable foundation for modern speech therapy practice.

First, citing Richard Schmidt himself, he cautioned in 2003 that “schema theory was intended to be an account of discrete actions. Hence, continuous actions, such as steering a car or juggling, which are both of longer duration (allowing time for response-produced feedback to have a role) and more based on the performer’s interactions with the environment were outside the area for schema theory…long-duration actions might be based on interplay between open-loop subactions and feedback-based corrections… . Interestingly, tasks such as juggling seem appropriate for analysis in terms of the dynamical systems perspective” (p. 367). I would argue that our understanding of, not only juggling, but speech motor control has benefited immensely from the dynamical systems perspective and I will come back to that in the next blog. If juggling is considered too complex and continuous to be explained by schema theory, probably speech is not a good fit either.

Second, modern theories of speech motor control have shown that on-line correction of motor action even over short durations occurs despite the limitations of feedback control. The explanation lies in the continuous operation of feedforward control mechanisms. More on feedforward control in another blog.

References

Rvachew, S., & Brosseau-Lapré, F. (2012). Developmental Phonological Disorders: Foundations of Clinical Practice. San Diego, CA: Plural Publishing.

Schmidt, R. A. (1975). A schema theory of discrete motor skill learning. Psychological Review, 82(4), 225-260. doi:10.1037/h0076770

Schmidt, R. A. (2003). Motor schema theory after 27 years: Reflections and implications for a new theory. Research Quarterly for Exercise and Sport, 74(4), 366-375.

Strand Edythe, A. (2019, Early View). Dynamic Temporal and Tactile Cueing: A Treatment Strategy for Childhood Apraxia of Speech. American Journal of Speech-Language Pathology. doi:10.1044/2019_AJSLP-19-0005

Using Apps for Speech Therapy

It seems like only a few days ago I promised to write a blog post on the best uses of apps for speech therapy, when I wrote about the Werfel study in my last blogpost. But it turns out that I made that promise 3 months ago! Time flies when you are School Director it turns out. But also, my thinking about why you might want to substitute an app for picture cards reminded me of a particularly traumatic event in my past and maybe I just didn’t want to revisit that memory. But here goes…when I was sent out on my first summer practicum as an undergraduate student sometime in the nineteen-seventies I was assigned to a health unit in rural Alberta. The placement involved driving a great big Ford around to schools on country roads which was scary enough because I had a driver’s licence, but I had never really driven on account of not owning a car. Anyway, on the very first day my supervisor asked me to carry all our materials out to the car so she piled my arms up with stuff, many files filled with papers, some board games, those plastic boxes full of articulation cards, and on top of that…her lunch! Of course, I dropped the load in the parking lot. You can imagine the scene — I am not going to describe the process of picking it all back up and trying to reorder everything before getting it in the back seat. To make it all worse, she then hands me the keys and tells me to drive because she is going to eat her lunch on the way. Her lunch included a can of grape pop. Now you can imagine how my glasses became painted with purple goop. All I can says is that it is lucky I did not drive the car off the road.

This story is actually relevant to the topic at hand because I want to talk about iPad apps relative to all the things I was carrying in my hands, excluding the lunch. Recall that Werfel implemented a therapy program in which the children named pictures on the screen and then swiped them off, one after the other, for 25 sessions over 8 weeks. Is this how we want to use apps? Why would we use apps? What are the advantages of apps over the boxes of pictures cards? Let’s go through the advantages one at a time.

  1. Storage

The first obvious advantage is that all the information and functionality carried in the files, the boxes of picture cards and even the board games can be stored on an iPad — a relatively small object that would have fit in the lunch bag or my purse. Not only that, the information can be password protected so it is an efficient and relatively secure way of carrying things around. At the same time the screen is large enough for two people to view and small hands to manipulate. I read that SLPs use a lot of apps built for phones because their employers do not provide them with iPads but everyone has their own iPhone. That is a real shame because the functionality of an iPad or other tablet is hard to beat.

  1. Multimedia

The second advantage of a digital app is the possibility of presenting information to children with multimedia correlation across different sensory modalities. Apps can present therapy stimuli with an integration of colourful and realistic visual representations, integrated text, sound effects and movement. Susan Neuman’s theory of synergy predicts that children learn and store more robust mental representations when they experience new information this way. Some experimental support for this idea was presented by Strouse & Ganea who randomly assigned 102 toddler-mother pairs to a print-book or ebook shared reading condition. The results were striking:

“Toddlers who were read the electronic books paid more attention, made themselves more available for reading, displayed more positive affect, participated in more page turns, and produced more content-related comments during reading than those who were read the print versions of the books. Toddlers also correctly identified a novel animal labeled in the book more often when they had read the electronic than the traditional print books.”

In this study the animation provided by the ebooks was very simple: when the toddlers patted the page, the sound associated with the illustrated animal was presented. Therefore, we have multimedia stimulation and an interactive component contributing to engagement and learning.

  1. Interactive Features

The variety of interactive features that are built into apps are boundless. In ebooks “hotspots” within the text or illustrations launch a variety of effects that may advance the story and support learning. Alternatively these animations, sound effects and games that occur when the hotspots are activated may be entertaining while not relevant to the story at all. These same kind of features can be used to create learning activities in the context of educational games meant to teach letter sounds or vocabulary or reading or a wide range of other skills. Many games are simply digital versions of conventional board games. Other games are meant to be fun and creative, involving free style drawing, opportunities to create characters and settings and stories in an open-ended fashion. Apps that encourage creativity are recommended for their “minds-on” properties. Hirsh-Pasek et al presented a framework for evaluating and choosing apps that rests on four pillars of learning: (1) the app encourages active learning; (2) in which the child is deeply engaged by the learning task; (3) the learning experience is meaningful in that it promotes connections between new knowledge and existing knowledge; and (4) the learning activity permits high quality social interaction or social contingency. These authors also review the science of learning and conclude that when the app is explicitly educational the learning program should be structured to provided “scaffolded exploration toward a learning goal.” Therefore, rote learning games in which the child, for example, simply names pictures and receives a tangible reward such as points in a token-economy game would not meet these criteria. A completely open-ended game with no learning goal would also not meet these criterial.

  1. Personalization

Perhaps the most exciting opportunities offered by tablets and the associated apps are the possibilities for personalization. It is possible for children to create their own stimuli and stories using the camera, drawing, and writing tools. In this way all the practice materials for speech and language therapy can be especially meaningful and relevant to the child’s daily life and special interests.

Using Apps in Speech Therapy

The first advantage to using apps in speech therapy is that it is possible to “think outside the articulation card box” and use other tools to practice speech accuracy in authentic communicative contexts. Let us imagine that you are working of velar stops with a child who typically fronts these consonants. You want an opportunity to product the sounds in relatively complex words while providing meaningful feedback using focused stimulation that is adapted for the speech therapy context as described by Rvachew & Brosseau-Lapré (2012). There are some electronic books that lend themselves to conversation that useful for this purpose. Consider the Nosy Crow book “Don’t Wake Up Tiger!” First there are several opportunities to produce velar sounds in conversation: tiger (contrasted with turtle), frog, cake, candle, pelican, fox). There is an active learning component in that the child must perform specific actions to help the different animals get around the tiger without waking him up in order to set up their surprise birthday party. There are matching games and five “spot the difference” games, the last one involving the birthday party scene, providing the opportunity for distancing prompts. The idea here is that articulation drill is not the best way to improve speech accuracy for the majority of children with speech delay or disorders in any case. You will want to choose different stories or games for older children but definitely choose apps that permit authentic conversation and minds-on learning.

It is also possible to create your own games for speech therapy drill very simply using presentation tools along with photos, clip art, or drawing tools. If you were practicing words that contain siblilants for example, the child could bring a photo of his house. Pasted into a series of slides, over top of cartoon characters and animated to disappear upon clicking or swiping, you have a very simple game. In this case, the child asks the question “Whose house?” and after swiping the house, a simple animation reveals the “It’s mouse’s house (sheep’s/zebra’s/seal’s etc.).” Many common software tools permit simple animations that are useful, turning a simple swipe into a game that connects meaning to the drill practice.

Of course, there are many commercial apps for drill therapy or minimal pairs games. I will not make the mistake of endorsing or criticizing any particular product. However, you will want to look for common problems when you download free games or purchase more sophisticated therapy tools. One common issue is putting text on the minimal pair cards so that the children are using letter cues rather than listening to the sound of speech and referring to their own underlying representations for words when playing the game that is involved. Another issue is poor choices of words from the point of view of phonological theory (e.g., “ball” and “bottle” are not both /l/-coda words). The old articulation card boxes had the same problem but it was often easier to shuffle through and exclude the words that did not fit the pattern you were working on. The commercial apps may or may not be that flexible.

In any case, I am sure that most of you are more familiar with these apps than I am and have lots of creative ideas for using them. The main point I wanted to make is that we should not let the tail wag the dog. It is really important to choose the most creative minds-on apps and not let the software coax us way back to the “drill and kill” days of the sixties. We have known for some time now that phonological therapy is all about meaning. The fun part of digital tools is the opportunity that multimedia and interactivity offers for helping children make connections between new learning and their prior experience.

Would you do speech therapy like this?

I was interested to read a paper about the relative efficacy of using traditional flash cards versus tablet presentation of pictures for articulation drill therapy because I have developed iPad apps myself (e.g., see www.DIALspeech.com) and have an interest in the potential of digital tools to enhance the speech therapy experience. The paper was recently published in the Online First section of Communication Disorders Quarterly by Krystel Werfel, Marren Brooks, and Lisa Fitton.

The study used a single subject alternating treatment design with four subjects, each kindergarten aged, —not clearly exhibiting signs of speech delay but none-the-less misarticulating two phonemes that could be practiced. Some statistical analyses (rather dubiously applied to single subject data) suggested that the children achieved mastery sooner in the flashcard condition but produced more correct responses in the tablet condition. To my eye, the data did not suggest a clear advantage to either condition. All the children did in fact master the treated phonemes (which were /z,s/, /pl,ɡl/, and /θ,ð/ (this pair for two children).

The authors make clear that the study is meant to be informative on the modality of stimulus presentation and not a test of the treatment protocol itself but I found myself alarmed at the possibility that readers might think that the treatment protocol would be reasonable in regular clinical practice and therefore I would like to address the way that the intervention was implemented. Often researchers implement a speech therapy intervention in a way that they would not in a regular clinical environment in an effort to exert more experimental control over all the variables than is typically necessary or desirable in an authentic clinical context. I can only hope that this explains some of the clinical choices that were made in this case. I am going to address several in turn as follows: (1) treatment approach; (2) treatment procedure; (3) reinforcement procedures; (4) cumulative intervention intensity; and (5) discharge criteria.

First, the authors state that they chose a traditional approach to therapy because there is empirical evidence that it works and clinicians prefer it. There is evidence of efficacy but in fact for most preschool aged children who qualify for speech services a phonological approach may be more efficacious as Francoise and I discuss in our text. Furthermore, the surveys indicating a preference for a traditional approach indicating that this is true in the United States but not elsewhere. Finally, there seems to be some confusion about what a “traditional” approach is. In some cases, traditional refers to a strict behaviorist intervention that focuses solely on speech production with a gradual increase in the complexity of speech units; in other cases it involves a sensory-motor approach with careful attention to variable speech practice and multiple targets; in other cases a traditional approach means Charles Van Riper’s approach which was properly sensory motor including both ear training, graduated speech practice and some principles of motor learning. The implementation in this paper was highly restricted involving only practice of single words and sometimes isolated sounds if necessary. If the speech therapist chooses a traditional rather than phonological approach it is best that the full sensory motor protocol be implemented.

Second, the drill based approach that was employed was selected again on empirical grounds. The study cited to support this approach was sound especially when treating children who have good speech perception abilities, most likely the case for the children in this study who did not have clear evidence of a speech disorder. Other approaches can be effective if procedures targeting phonological processing are incorporated into the intervention as shown by Hesketh and colleagues in the U.K. and also by me and Francoise with French-speaking children.

The strangest part of the whole intervention is that the children experienced over 25 treatment sessions each and throughout every session identical practice trials occurred: a stimulus prompt was presented, the child attempted to name the picture, the clinician provided feedback or extra support and then if the child’s response was correct he or she was permitted to mail the flash card or swipe the picture of the tablet. That was it. For eight weeks. I’m speechless. Enough said.

Regarding cumulative intervention intensity, I indicated in previous blogs that children should receive a minimum of 50 practice trials and ideally 100 practice trials per session. Furthermore, other single subject research using a minimal pairs procedures indicates that generalization goals are not usually met with fewer than 180 practice trials (when treating children with moderate or severe phonological delays). In Werfel’s study the children received treatment for two sounds in 20 minutes, so ten minutes per sound and 15 practice trials per sound or 10-minute block, therefore 30 practice trials per 20-minute treatment session. Reportedly, the mastery was achieved after 203 trials in the flashcard condition and 270 trials in the tablet condition (equivalent to 135 and 180 minutes of therapy respectively). However, increasing the number of practice trials to 50 during that 20-minute session could reduce the number of sessions or weeks in the intervention program by almost half. One way to do that would be to reduce the amount of feedback that was provided. The intervention was designed so that the clinician provided explicit feedback to the child after every practice attempt whereas the principles of motor learning suggest that less feedback is often better for speech motor learning. For example, a child can name five pictures in a row and be told that four of the five productions were correct. Another strategy is to practice at the challenge point at all times as described in detail by Francoise and I in Developmental Phonological Disorders: Foundations of Clinical Practice but also in our new undergraduate text Introduction to Speech Sound Disorders.

Finally, the discharge or stopping criteria in the study were set at 100% correct performance on the generalization probe over 3 consecutive sessions. The probe contained 5 treated words and 5 untreated words. This criterion meant that children practiced their targets for a long time past the point at which the practice material should have been made more difficult or the child should have been discharged to see if spontaneous generalization to natural speaking situations would occur. As Francoise and I review in Chapter 8 of our book, several studies have shown that children can be discharged after achieving between 40 and 80% correct responding on generalization probes. Most children will continue to make gains in production accuracy after this point. The four children in the Werfel et al study received an average of 5 unnecessary treatment sessions according to these criteria.

When conducting treatment studies, it is helpful to provide models of treatment procedures that are best practice in the clinical setting. Often interventions that are better than no intervention will prove to be effective in a research setting while not necessarily being best practice. These studies are confusing for a clinical audience I think. Furthermore, when asking clinical questions about new technologies it is interesting to ask, why would we want to bring it into our clinical practice? What benefit might it bring? How can we adapt these technologies so that the best of human interactions are retained and the most benefit of the technology is added? In my next blog I will address the Werfel study again, but this time imagining the questions we might ask about tablet-based implementations of articulation therapy.

How to score iPad SAILS

As the evidence accrues for the effectiveness of SAILS as a tool for assessing and treating children’s (in)ability to perceive certain phoneme contrasts (see blog post on the evidence here), the popularity of the new iPad SAILS app is growing. Now I am getting questions about how to score the new SAILS app on the iPad so I provide a brief tutorial here. The norms are not built into the app since most of the modules are not normed. However, four of the modules are associated with normative data and can be used to give a sense of whether children’s performance is within the expected range according to age/grade level. Those normative data have been published in our text “Developmental Phonological Disorders: Foundations of Clinical Practice” (derived from the sample described in Rvachew, 2007) but I reproduce the table here and show how to use it.

When you administer the modules lake, cat, rat and Sue you will be provided with an overall Level score for all the Levels in each module as well as item by item scores on the Results page. As an example, I show the results page below after administering the  rat module.

SAILS results screenshot rat

The screen shot shows the item-by-item performance on the right hand side for Level 2 of the rat module. On the left hand side we can see that the total score for Level 2 was 7/10 correct responses and the total score for Level 1 was 9/10 correct responses (we ignore responding to the Practice Level). To determine if the child’s perception of “r” is within normal limits, average performance across Levels 1 and 2: [(9+7)/20]*100 = 80% correct responses. This score can be compared to the normative data provided in Table 5-7 of the second edition of the DPD text, as reproduced below:

SAILS Norms RBL 2018

Specifically a z-score should be calculated: (80-85.70)/12.61 = -.45. In other words, if the child is in first grade, the z score is calculated by taking the obtained score of 80% minus the expected score of 85.70% and dividing the result by the standard deviation of 12.61 which gives a z score that is less than one standard deviation below the mean. Therefore, we are not concerned about this child’s perceptual abilities for the “r” sound. When calculating these scores, observe that some modules have one test level, some have two and some have three. Therefore the average score is sometimes based on 10 total responses, sometimes on 20 total responses as shown here, and sometimes on 30 total responses.

The child’s total score across the four modules lake, cat, rat and Sue can be averaged (ignoring all the practice levels) and compared against the means in the row labeled “all four”. Typically you want to know about the child’s performance on a particular phoneme however because generally children’s perceptual difficulties are linked to those phonemes that they misarticulate.

Normative data has not been obtained for any of the other modules. Typically however, a score of 7/10 or less than 7/10 is not a good score – a score this low suggests guessing or not much better than guessing given that this is a two alternative forced choice task.

Previously we have found that children’s performance on this test is useful for treatment planning in that children with these speech perception problems will achieve speech accuracy faster when the underlying speech perception problem is treated. Furthermore, poor overall speech perception performance  in children with speech delay is associated with slower development of phonological awareness and early reading skills.

I hope that you and your clients enjoy the SAILS task which can be found on the App Store, with new modules uploaded from time to time: https://itunes.apple.com/ca/app/sails/id1207583276?mt=8

 

Feedback Errors in Speech Therapy

I have been spending hours reviewing video of student SLPs (SSLPs) conducting speech therapy sessions, looking for snippets to take to my upcoming talks at ASHA2018. The students are impressively skilled with a very difficult CAS population but after this many hours of watching, repeated examples of certain categories of errors pile up in the provision of feedback to children about their attempts to produce the targets words, phrases and sentences. I am going to provide some examples here with commentary. In no way am I meaning any disrespect to the students because it is my experience that the average person becomes an idiot when a camera is pointed at them. I recall hearing about studies on the “audience effect” as an undergraduate – the idea is that when your skills are shaky you get worse when someone is watching but when your skills are excellent an audience actually enhances them. My social psychology prof said this even works for cockroaches! I can’t vouch for that but it certainly works for speech pathologists. I remember one time video-taping a session that was required for a course – I thought it went really well so I gave a copy to the parents and the course instructor. Later when watching it I could see clearly that for the whole half hour the child was trying desperately and without success to tell me that I was calling him by the wrong name (I had mixed him up with his twin brother whom I was also treating). I was oblivious to this during the live session but it was clear on the video. Anyway, these examples are not reflections on the students’ skill levels overall but they are examples of common feedback errors that I see in novice and experienced SLPs. Interestingly the clinical educators (CEs) who were supervising these sessions rarely mentioned this aspect of the students’ practice. Readers may find this blog useful as a template for reviewing student practice.

Category 1: No feedback

Child: [repeats 5 different sentences containing the target /s/ cluster words]

SSLP: [Turns to CE.] “What did you get?” [This is followed by 1 minute and 40 seconds of conversation about the child’s level of accuracy and strategies to improve it on the next block of trials.]

SSLP: [Turns back to child.] “You need to sit up. You got 2 out 5 correct. Now we’re going to count them on my fingers…”

Child: “Do we have to say these?”

Comment on vignette: In this case the SSLP did finally give feedback but too late for it to be meaningful to the child and after the telling the child off for slouching in her chair! Other variants on this are taking notes about the child’s performance or turning to converse with the child’s parent or getting caught up in the reinforcement game and forgetting to provide feedback. In CAS interventions it is common to provide feedback on a random schedule or to provide summative feedback after a block of trials. However, the child should be able to predict the block size and have information about whether their performance is generally improving or not. Even if the child does not have a count of number or percent trials correct, the child should know that practice stimuli are getting more difficult, reflecting performance gains. Sometimes, we deliberately plan to not provide feedback because we want the child to evaluate his or her own productions, but in these cases the child is told beforehand and the child is given a means of explicitly making that judgment (e.g., putting token in jar). Furthermore, the SSLP would be expected to praise the child for making accurate self-judgments or self-corrections. When the child does not get feedback or cannot track their own progress they will lose interest in the activity. It is common for SSLPs to change the game thinking that it is not motivating enough but there is nothing more motivating than a clear sense of success!

Possible solutions: Video record sessions and ask students to watch for and count the frequency of events in which the child has not received expected feedback. Provide child with visual guides to track progress indexed either as correct trials or difficulty of practice materials.

Category 2: Ambiguous feedback

SSLP: “Say [ska].”

Child: “[skak]”

SSLP: “OK, take the fish out.”

Comment on the vignette: In this case it is not clear if the SSLP is accepting the inexact repetition of her model. In our CAS interventions we expect the child to produce the model exactly because metathesis and other planning errors are common and therefore I would consider this production to be incorrect. Other ambiguous feedback that I observed frequently were “Good try” and “Nice try” and similar variants. In these cases the child has not received a clear signal that the “try” was incorrect. Another version of ambiguous feedback is to comment on the child’s behavior rather than the child’s speech accuracy (e.g., “You did it by yourself!” in which case the “it” is ambiguous to the child not clearly related to the accuracy of the child’s speech attempts).

Possible solutions: SSLPs really do not like telling children that have said something incorrectly. Ask students to role play firm and informative feedback. Have the students plan a small number of clear phrases that are acceptable to them as indicators of correct and incorrect responses (e.g., “I didn’t hear your snake sound” may be more acceptable than “No, that’s wrong”). Post written copies of the phrases somewhere in the therapy room so that the SLP can see them. Track the use of vague phrases such as “nice try” and impose a mutually agreed but fun penalty for exceeding a threshold number (buy the next coffee round for example). This works well if students are peer coaching.

Category 3: Mixed signals

SSLP: “Say [ska].”

Child: “[s:ka]”

SSLP: “Good job! Take the fish out.” [Frown on face].

Comment on the vignette: I am rather prone to this one myself due to strong concentration on next moves! But it is really unhelpful for children with speech and language delays who find the nonverbal message much easier to interpret than the verbal message.

Possible solutions: It would be better if SLP therapy rooms looked like a physiotherapy room. It annoys the heck out of me when we can’t get them outfitted with beautiful wall to ceiling mirrors. The child and SLP should sit or stand in front of the mirror when working on speech. Many games can be played using ticky tack or reusable stickers or dry erase pens. The SLP will be more aware of the congruence or incongruence between facial expressions, body language and verbal signals during the session.

Category 4: Feedback that reinforces the error

SSLP: “Repeat after me, Spatnuck” [this is the name of a rocket ship in nonsense word therapy].

Child: “fatnuck”

SSLP: “I think you said fatnuck with a [f:] instead of a [s:].

Comment on the vignette: Some SSLPs provide this kind of feedback so frequently that the child hears as many models of the incorrect form as the correct form. This is not helpful! This kind of feedback after the error is not easy for young children to process. To help the child succeed, it would be better to change the difficulty level of the task itself and provide more effective support before the next trial. After attempts, recasting incorrect tries and imitating correct tries can help the child monitor their own attempts at the target.

Possible solutions: Try similar strategies as suggested for ambiguous feedback. Plan appropriate feedback in advance. Plan to say this when the incorrect response is heard: “I didn’t hear the snake sound. Let’s try just the beginning of the word, watch me: sss-pat.” And when “spat” is achieved, plan to say “Good, I heard spat, you get a Spatnuck to put in space.”

Category 5: Confused feedback

SSLP: “Oh! Remember to curl your tongue when you say shadow.”

SSLP: “Oh! You found another pair.”

Child: “It’s shell [sʷɛo].”

SSLP: “Oh! I like the way you rounded your lips. Where is your tongue? Remember to hide your tongue.”

SSLP: Oh! You remembered where it was. You found another pair.”

Child: “Shoes [sʷuz].”

SSLP: “Oh! I like the way you rounded your tongue.”

Comment on vignette: In this vignette the SSLP is providing feedback about three aspects of the child’s performance-finding pairs when playing memory, rounding lips when attempting “sh” sounds, and in some cases anterior tongue placement when attempting the “sh” sound as well. One aspect of her feedback that is confusing when watching the video is the using of the exclamation “Oh!” Initially it appeared to signal an upcoming correction but it became so constant that it was not a predictable signal of any kind of feedback and was confusing. The exclamation had a negative valence to it but it might precede a correction or positive feedback. The SSLP confused her feedback about lips and tongue and it was not clear whether she was expecting the child to achieve the correct lip gesture, the correct tongue gesture or both at the same time.

Possible solutions: This can happen when there is too much happening in a session. The CE could help the SSLP restructure the session so that she can focus her attention on one aspect of the child’s behavior at a time, like this: “I want you to name these five pictures. Each time I am going to watch your lips. When you are done you can put the pictures on the table and mix them up for our game later.” If the child rounds the lips each time, switch to focusing on the tongue. When the ten cards are on the table play memory, modeling the picture names. In this way the three behaviors (rounding lips, retracting tongue, finding pairs) are separated in time and the SSLP can focus attention on each one with care, providing appropriate feedback repeatedly during the appropriate intervals.

Category 6: Confused use of reinforcement materials

SSLP: “Repeat after me, [ska].”

Child: “[θak]”

SSLP: [ska]

Child: “[θak]”

SSLP: “OK, take the fish out.”

SSLP: “Repeat after me, [ska].”

Child: [ska]

SSLP: “There you got it, take the fish out.”

SSLP: “Repeat after me, [ska].”

Child: [ska]

SSLP: “Good, and the last one, [ska].”

Child: [ska]

SSLP: “That’s good, take the fish out.”

Comment on vignette: In this vignette the child cannot tell if he gets a fish for correct answers or wrong answers or any answer. It is even worse if the child has been told that he will get a fish for each correct answer. Sometimes a student will say “Everything was going fine, we were having fun and then he just lost it!” When you look at the video you see exchanges such as the one reproduced here leading up to a tantrum by the child. The SSLP has broken a promise to the child. They don’t forgive that.

Possible solutions: This one is hard because it is a classic rooky mistake. Experience is the best cure. Reducing the number of tasks that the SSLP must do simultaneously may help. Therefore, in the early sessions the CE might keep track of the child’s correct and incorrect responses for the SSLP and allow her to focus on managing the materials and the child’s behavior. SSLPs would never think of this but it is possible to let the child manage the reinforcement materials themselves in some cases. One of our favorite vignettes, reprinted on page 463 of DPD2e (Case Study 9-4) involved an error detection activity in which the child could put toy animals in the barn but only when the SSLP said the names of the animals correctly. The child had the toys in his hands throughout the activity. He would not put them in the barn unless the clinician said the words correctly and would get annoyed if she said them wrong, telling her “you have to say cow [kau]!” SSLPs can learn that it is not necessary to control everything.

I put these here for students and clinical educators and speech-language pathologists and hope that you will have fun finding these feedback mishaps in your own sessions. If you come up with better strategies to avoid them than I have suggested here please share them in the comments.

Conversations with SLPs: Nonword Practice Stimuli

I often answer queries from speech-language pathologists about their patients or more abstract matters of theory or clinical practice and sometimes the conversations are general enough to turn into blog topics. On this occasion I was asked my opinion about a specific paper with the question being generally about the credibility of the results and applicability of the findings to clinical practice:

Gierut, J., Morrisette, M. L., & Ziemer, S. M. (2010). Nonwords and generalization in children with phonological disorders. American Journal of Speech-Language Pathology, 19, 167-177.

In this paper the authors conduct a retrospective review of post treatment results obtained from 60 children with a moderate-to-severe phonological delay who had been treated in the context of research projects gathered under the umbrella of the “learnability project”. Half of these children had been taught nonwords and the remainder real words, representing phonemes for which the children demonstrated no productive phonological knowledge. The words (both the nonword targets and the real word targets) were taught in association with pictured referents, first in imitation and then in spontaneous production tasks. Generalization to real word targets was probed post-treatment. Note that the phonemes probed included those that were treated and any others that the child did not produce accurately at baseline. The results show an advantage to treated over untreated phonemes that is maintained over a 55 day follow-up interval. Greater generalization was observed for children who received treatment for nonwords compared to those children who received treatment for real words, but only for treated phonemes and only immediately post treatment because over time the children who received treatment for real words caught up to the other group.

OK, so what do I think about this paper. Overall, I think that it provides evidence that it is not harmful to use nonwords in treatment which is a really nice result for researchers. As Gierut et al explain, nonwords are handy because “they have been incorporated into research as a way of ensuring experimental control within and across children and studies.” They can be designed to target the specific phonological strengths and needs of each child and it is very unlikely that the family or school personnel will practice them outside of clinic and therefore it is possible to conclude that change is due to the experimental manipulation. Gierut et al go one step further however and conclude that nonword stimuli might offer an advantage for generalization learning because “the newness of the treated items might reduce interference from known words.” Here I think that the evidence is weaker simply because this is a nonexperimental study. The retrospective nature of the study and the fact that children were not assigned with blind random assignment in one cohort to be taught with one set of stimuli vs the other while holding other aspects of the design constant limits the conclusions that one can draw. For example, the authors point out that the children who were treated with nonwords received more treatment sessions than those treated with real words. Therefore, in terms of clinical implications, the study does not offer much guidance to the SLP beyond suggesting that there may be no harm in using nonword stimuli if the SLP has specific reasons for doing so.

We can offer experimental prospective evidence on this topic from my lab however. It is also limited in that it involves only two children but they were both treated with a single subject randomization design that provides excellent internal validity. This study was conducted by my former student Dr. Tanya Matthews with support from Marla Folden, M.Sc., S-LP(C). The interventions were provided by McGill students in speech-language pathology who were completing their final internship. The two children presented with very different profiles: TASC02 had childhood apraxia of speech with an accompanying cognitive delay and ADHD. TASC33 presented with a mild articulation delay and verbal and  nonverbal IQ within normal limits.

Both children were treated according to the same protocol: they received 18 treatment sessions, provided 3 per week for 6 weeks. Each week they experience three different treatment conditions, randomly assigned to one of the 3 sessions and a unique target as shown in the table below for the two children. Each session consisted of a preprepractice portion and a practice portion. The prepractice was either Mixed Procedures (auditory bombardment, error detection tasks, phonetic placement, segmentation and chaining of segments with the words) or Control (no prepractice). In all three conditions practice was high intensity practice employing principles of motor learning.

realword vs nonword conditions

Random assignment of condition/target pairs to sessions within weeks permits the use of resampling tests to determine if there are statistically significant differences in outcomes as a function of treatment condition. Outcomes were assessed via imitation probes that were administered at the end of each treatment session to measure generalization to untreated items (same day probes) and probes that were administered approximately 2 days later (at the beginning of the next treatment session) to measure maintenance of those learning gains (next day probes). The next table shows the mean probe scores by condition and child, the test statistic (squared mean differences across conditions) and the associated p value for the treatment effect for each child.

realword vs nonword outcomes

The data shown in this table reveal no significant results for either child for same day or next day probe scores. In other words there was no advantage to the prepractice versus no prepractice condition and there was no advantage to nonword practice over real word practice.

We hope to publish some data soon that suggests that the specific type of prepractice might make a difference for certain children. But overall the most important driver of outcomes for children with speech sound disorders seems to be practice and lots of it.

Is Acoustic Feedback Effective for Remediating “r” Errors?

I am very pleased to see a third paper published in the speech-language pathology literature using the single-subject randomization design that I have described in two tutorials, the first in 1988 and the second more recently. Tara McAllister Byun used the design to investigate the effectiveness of acoustic biofeedback treatment to remediate persistent “r” errors in 7 children aged 9 to 15 years. She used the single subject randomized alternation design with block randomization, including a few unique elements in her implementation of the design. She and her research team provided one traditional treatment session and one biofeedback treatment session each week for ten weeks. However the order of the traditional and biofeedback sessions was randomized each week. Interestingly, each session targeted the same items (i.e., “r” was the speech sound target  in both treatment conditions): rhotic vowels were tackled first and consonantal “r” was introduced later, in a variety of phonetic contexts. (This procedure is a variance from my experience in which, for example, Tanya Matthews and I randomly assign different targets to different treatment conditions). Another innovation is the outcome measure: a probe constructed of untreated “r” words was given at the beginning and end of each session so that change (Mdif) over the session was the outcome measure submitted to statistical analysis (our tutorial explains that the advantage of the SSRD is that a nonparametric randomization test can be used to assess the outcome of the study, yielding a p value).  In addition, 3 baseline probes and 3 maintenance probes were collected so that an effect size for overall improvement could be calculated. In this way there are actually 3 time scales for measuring change in this study: (1) change from baseline to maintenance probes; (2) change from baseline to treatment performance as reflected in the probes obtained at the beginning of each session and plotted over time; and (3) change over a session, reflected in the probes given at the beginning and the end of each session. Furthermore, it is possible to compare differences in within session change for sessions provided with and without acoustic feedback.

I was really happy to see the implementation of the design but it is fair to say that the results were a dog’s breakfast, as summarized below:

Byun 2017 acoustic biofeedback

The table indicates that two participants (Piper, Clara) showed an effect of biofeedback treatment and generalization learning. Both showed rapid change in accuracy overall after treatment was introduced in both conditions and maintained at least some of that improvement after treatment was withdrawn. Garrat and Ian showed identical trajectories in the traditional and biofeedback conditions with a late rise in accuracy during treatment session, large within session improvements during the latter part of the treatment period, and good maintenance of those gains. Neither boy achieved 60% correct responding however at any point in the treatment program. Felix, Lucas and Evan demonstrated no change in probe scores across the twenty weeks of the experiment in both conditions. Lucas started at a higher level and therefore his probe performance is more variable: because he actually showed a within session decline during traditional sessions while showing stable performance within biofeedback sessions, the statistics indicate a treatment effect in favour of acoustic biofeedback but in fact no actual gains are observed.

So, this is a long description of the results that brings me to two conclusions: (1) the alternation design was the wrong choice for the hypothesis in these experiments; and (2) biofeedback was not effective for these children; even in those cases where it looks like there was an effect, the children were responsive to both biofeedback and the traditional intervention.

In a previous blog, I described the alternation design; there is another version of the single subject randomization design that would be more appropriate for Tara’s hypothesis however.  The thing about acoustic biofeedback is that it is not fundamentally different from traditional speech therapy, involving a similar sequence of events: (i) SLP says a word as an imitative model; (ii) child imitates the word; (iii) SLP provides informative or corrective feedback. In the case of incorrect responses in the traditional condition in Byun’s study, the SLP provided information about articulatory placement and reminded the child that the target involved certain articulatory movements (“make the back part of your tongue go back”). In the case of incorrect responses in the acoustic biofeedback condition, the SLP made reference to the acoustic spectrogram when providing feedback and reminded the child that the target involved certain formant movements (“make the third bump move over”). Firstly, the first two steps are completely overlapping in both conditions and secondly it can be expected that the articulatory cues given in the traditional condition will be remembered and their effects will carry-over into the biofeedback sessions. Therefore we can consider the acoustic biofeedback to be an add-on to traditional therapy. We want to know about the value added. Therefore the phase design is more appropriate: in this case, there would be 20 sessions (2 per week over 10 weeks as in Byun’s study), each session would be planned with the same format: beginning probe (optional), 100 practice trials with feedback, ending probe. The difference is that the starting point for the introduction of acoustic biofeedback would be selected at random. All the sessions that precede the randomly selected start point would be conducted with traditional feedback and all the remainder would be conducted with acoustic biofeedback. The first three would be designated as traditional and the last 3 would be designated as biofeedback for a 26 session protocol as described by Byun. Across the 7 children this would end up looking like a multiple baseline design except that (1) the duration of the baseline phase would be determined by random selection for each child; and (2) the baseline phase is actually the traditional treatment with the experimental phase testing the value added benefit of biofeedback. There are three possible categories of outcomes: no change after introduction of the biofeedback, an immediate change, or a late change. As with any single subject design, the change might be in level, trend or variance and the test statistic can be designed to capture any of those types of changes. The statistical analysis asks whether the obtained test statistic is bigger than all possible results given all of the possible random selection of starting points. Rvachew & Matthews (2016) provides a more complete  explanation of the statistical analysis.

I show below an imaginary result for Clara, using the data presented for her in Byun’s paper, as if the traditional treatment came first and then the biofeedback intervention. If we pretend that the randomly selected start point for the biofeedback intervention occurred exactly in the middle of the treatment period, the test statistic is the difference of the M(bf) and the M(trad) scores resulting in -2.308. All other possible random selections of starting points for intervention lead to 19 other possible mean differences, and 18 of them are bigger than the obtained test statistic leading to a p value of 18/20 = .9. In this data set the probe scores are actually bigger in the earlier part of the intervention when the traditional treatment is used and they do not get bigger when the biofeedback is introduced. These are the beginning probe scores obtained by Clara but Byun obtained a significant result in favour of biofeedback by block randomization and by examining change across each session. However, I am not completely sure that the improvements from beginning to ending probes are a positive sign—this result might reflect a failure to maintain gains from the previous session in one or the other condition.

Hypothetical Clara in SSR Phase Design

There are several reasons to think that both interventions that were used in Byun’s study might result in unsatisfactory generalization and maintenance. We discuss the principles of generalization in relation to theories of motor learning in Developmental Phonological Disorders: Foundations of Clinical Practice. One important principle is that the child needs a well-established representation of the acoustic-phonetic target. All seven of the children in Byun’s study had poor auditory processing skills but no part of the treatment program addressed phonological processing, phonological knowledge or acoustic phonetic representations. Second, it is essential to have the tools to monitor and use self-produced feedback (auditory, somatosensory) to evaluate success in achieving the target. Both the traditional and the biofeedback intervention put the child in the position of being dependent upon external feedback. The outcome measure focused attention on improvements from the beginning of the practice session to the end. The first principle of motor learning is that practice performance is not an indication of learning however.  The focus should have been on the sometimes large decrements in probe scores from the end of one session to the beginning of the next. The children had no means of maintaining any of those performance gains. Acoustic feedback may be a powerful means of establishing a new response but it is a counterproductive tool for maintenance and generalization learning.

Reading

McAllister Byun, T. (2017). Efficacy of Visual–Acoustic Biofeedback Intervention for Residual Rhotic Errors: A Single-Subject Randomization Study. Journal of Speech, Language, and Hearing Research, 60(5), 1175-1193. doi:10.1044/2016_JSLHR-S-16-0038

Rvachew, S., & Matthews, T. (2017). Demonstrating treatment efficacy using the single subject randomization design: A tutorial and demonstration. Journal of Communication Disorders, 67, 1-13. doi:https://doi.org/10.1016/j.jcomdis.2017.04.003