Getting the most “Bang for your Buck” with CAS treatment (with a bonus review of DTTC!)

Treating kids with childhood apraxia of speech (CAS) can be an involved and lengthy process. So what are the optimal conditions for CAS treatment? Maas et al. are on it, giving insight into how we can structure our therapy for kids with CAS. They provided integral stimulation treatment (see below), that differed based on the amount and distribution of practice.

Practice amount (aka cumulative intervention intensity) is the “number of practice trials and sessions provided throughout the treatment period”. Unsurprisingly, more therapy generally led to greater gains for children in this study (ages 4–12, who all had at least 50 words). The more a child practices saying a target word, the more opportunities he has to learn and retain the movement pattern.

Practice distribution refers to how the practice is divided over time, either many trials in a short period (massed practice) or spread out over a longer one (distributed practice). Massed practice led to greater improvement and maintenance of target words for most children in the study. This is consistent with neuroplasticity literature (yay science!). Massed practice might look like working on five targets for four weeks, and then five new targets for four weeks, rather than ten targets for eight weeks straight.

4.png

This study also gives us a great review of integral stimulation treatment (the basis of Dynamic Temporal and Tactile Cueing, or DTTC), which is one of the most evidence-based treatments out there for CAS. As a preview the core aspects of integral stimulation are: (1) tactile cues, (2) slowed rate of speech, (3) gradual fading of cues, and (4) focus on whole-target movement accuracy. Free CEUs and downloadable charts are available to learn how to deliver DTTC, so look into it if you serve these kids!

 

Maas, E., Gildersleeve-Neumann, C., Jakielski, K., Kovacs, N., Stoeckel, R., Vradelis, H., & Welsh, M. (2019). Bang for your buck: A single-case experimental design study of practice amount and distribution in treatment for childhood apraxia of speech. Journal of Speech, Language, and Hearing Research. doi:10.1044/2019_JSLHR-S-18-0212

CAS may go beyond speech

Childhood apraxia of speech (CAS) can present some of the most challenging “speech-only” cases. But have you ever had a parent ask you if their child needs more than just speech therapy? For example, have they, or you, ever noticed that their child with CAS also seems a little clumsier than a typical child?

Turns out, in a sample of children ages 3–15 with CAS, 49% also met the criteria for developmental coordination disorder (DCD), compared to 5–6% of the general population. Developmental coordination disorder presents as a difficulty of acquisition and execution of coordinated motor skills. These motor impairments can significantly impact a child’s ability to perform daily acts of living, including academics, self-care, and leisure activities. Symptoms may include an unsteady walk, difficulty acquiring motor skills like tying shoes or using scissors, and frequent dropping or running into objects.   

While it makes sense that children with motor planning difficulties for speech may also have general motor difficulties, SLPs have an advocacy role to play here. We need to be aware that children with CAS may need additional support from OT or PT, and that CAS and DCD can be successfully managed from a young age if addressed early and in a collaborative manner.

Duchow et al. encourage SLPs treating children with CAS to engage in interdisciplinary evaluation and treatment, as difficulties with both communication and motor skills significantly impact academic achievement and social participation. The authors encourage SLPs to utilize the Developmental Coordination Disorder Questionnaire (free!) to screen for the disorder in children ages 5–15 (There is a preschool version available for $50). If you don’t regularly work with OT or PT, appropriate referrals should be made.

2.png

Editor’s Note: Never heard of developmental coordination disorder (DCD)? I hadn’t either! So, of course after reading this article, we had to dig a bit deeper. First, the disorder goes by other names, (e.g. global apraxia; developmental dyspraxia), though DCD seems to be the more current term. To learn more about DCD, I’d highly recommend these articles: this recent one is definitely the most thorough; this is a commentary on that article. Then this and this are also good. Long story short—after reading the research and emailing several PTs and OTs, it seems like this disorder is much more commonly diagnosed in Europe and Canada, and tends to be a bit difficult to get insurance coverage for in the U.S. But we encourage you to discuss this and collaborate with local colleagues—because it definitely looks like there’s more and more research being done, and it will very likely come up in your clinical practice sooner or later! ~ Meredith Harold, PhD, CCC-SLP

 

Duchow, H., Lindsay. A., Roth, K., Schell, S., Allen, D., & Boliek, C.A. (2019). The co-occurrence of possible developmental coordination disorder and suspected childhood apraxia of speech. Canadian Journal of Speech-Language Pathology and Audiology.  

Targeting both speech perception and production for CAS

We think of childhood apraxia of speech (CAS) as a motor speech disorder, so it makes sense that our interventions mostly treat speech production. But what about all the children with CAS who also have language and reading weaknesses? Some evidence suggests that therapy to improve speech perception (think phonological awareness skills) can also benefit children with CAS. 

13.png

In this study, Hume et al. used a combined perception and production treatment with six children with CAS (ages 4–7) who were making slow progress in therapy. They used a pretest–posttest design (basically six case studies)—so the study design isn’t the strongest. But we don’t have a ton of treatment studies on children with CAS, and descriptive studies can still give us ideas for our clients, so the results are still worth a look.

During individual, 50-minute sessions, an SLP led children in: (1) rhyming practice, (2) phonological awareness activities using target sounds or sound patterns, (3) speech production practice, and (4) generalization practice (using target sounds in a new context). Following 30 treatment sessions, all children improved their production of untaught words and their consistency of word productions, and five of the six children improved on tests of phonological awareness.

Again, with a nonexperimental study, we can’t say whether the treatment caused children’s progress. However, the results match findings from other studies that suggest perception practice might benefit children with CAS. If you have clients with CAS who are making slow progress in therapy and who also struggle with reading or pre-reading skills, tacking on some phonological awareness practice might be worth a try. 

Hume, S. B., Schwarz, I., & Hedrick, M. (2018). Preliminary investigation of the use of phonological awareness paired with production training in childhood apraxia of speech. Perspectives of the ASHA Special Interest Groups, 3 (SIG 16), 38–52.

Teasing out morphology vs. speech skills in preschoolers

Researchers tend to talk about speech OR language impairment, when in reality, we know that it’s rarely so simple. Two studies this month looked at morphology skills in preschoolers with speech sound disorders, and ways to untangle the effects of each.

14.png

Murray et al. looked at assessment data from studies of preschoolers with childhood apraxia of speech (CAS) who all were given the CELF-P2. They found that children with CAS had lower expressive than receptive language skills overall. Morphology was particularly difficult for children with CAS, and errors were inconsistent across the same morphemes. While some morpheme errors were speech-based, others were language-based. Unfortunately, assessing morphology skills independently of speech skills is difficult, especially in connected speech.

The takeaway is that morphological skills should be part of our assessment process for children with CAS, but we need to consider whether children’s speech skills are causing the morpheme errors we see.

So, how can we do that? Howland et al. have some suggestions. They looked at grammatical morpheme production in preschoolers with phonological impairment (defined as speech sound disorder with pattern-based errors). They found that, for these kids:

  • Past tense –ed was harder than all other morphemes. Morphemes like third person singular -s were harder than morphemes like plural or possessive -s.  

  • Morphemes in clusters (e.g., wants) were harder than morphemes in singletons (e.g., sees) or syllables (e.g., washes).

  • Children who could produce final clusters in single-morpheme words (e.g., waste) were more likely to use morphemes correctly overall.

So basically, children’s speech skills affect their ability to use morphemes. We can try to see whether the issue is caused by phonology or morphology by sampling sounds and clusters in single-morpheme vs. multi-morpheme words. Standardized tests don’t necessarily do this well, so it’s worth our time to do more probe testing to tease it out. What could this look like? Check out the example word pairs below. We’re asking, is it clusters that this child can’t do? Or morphemes?

2.png

Early speech and language disorders affect later spelling

SLPs are well-aware that speech, language, and literacy are all interconnected, but we’re also aware that they’re not necessarily interconnected in a nice, clear, easy-to-understand way. This study helped to sharpen our vision on whether we should expect later spelling difficulty in children with early speech and language disorders.

First, a quick refresher. There are a couple of skills kids need in order to have good spelling skills. One is phonological awareness. The other is RAN, or rapid automatized naming (e.g., naming a set of colors or animals as fast as possible). While RAN is usually studied in the context of reading, it can also affect spelling, and can predict spelling difficulty in children, especially for irregular words (see here for more on RAN and spelling).  In addition to the skills associated with spelling, there is also a genetic factor: spelling difficulty (and reading, learning, language, etc.) can run in families. On top of all of that, we know from existing research and clinical experience that children with speech sound and language disorders are at risk for later reading and spelling impairments.  

The authors tested participants from a large longitudinal study to explore how these factors contribute to spelling ability in middle- and high-school students. Children who were tested between 4- and 6-years of age were split into groups* based on diagnosis:

  • No SSD/DLD

  • SSD only

  • SSD + DLD

  • CAS (these children also all had DLD)

All children were assessed again at middle school or high school age on phonological awareness, RAN, reading decoding, and spelling. Interestingly, the results indicated that having SSD alone was not associated with spelling difficulty in later school years, but children with SSD + DLD and children with CAS (who also met criteria for DLD) showed continued spelling difficulty into middle- and high-school. Taking a closer look at the underlying skills needed for spelling, phonological awareness was related to spelling scores at middle- and high-school, but RAN was only related to spelling scores in the high school group.

17.png

The authors also looked at heritability of spelling skills. Heritability looks at the probability that differences in a trait (in this case, spelling) occur because of genetic reasons and not because of environmental factors or by chance. Controlling for diagnosis and socio-economic status, the authors found strong heritability only in the high school group, meaning that genetic factors are probably more important in later spelling skills while environmental factors are more at play in the earlier years. Based on the results of the study, authors suggest we should keep a close eye on children with early SSD and DLD and intervene for those students who are showing early signs of spelling and reading difficulty.

*SSD = speech sound disorder; DLD = developmental language disorder; CAS = childhood apraxia of speech)

 

Lewis, B. A., Freebairn, L., Tag, J., Benchek, P., Morris, N. J., Iyengar, S. K., …, & Stein, C., M. (2018). Heritability and longitudinal outcomes of spelling skills in individuals with histories of early speech and language disorders. Learning and Individual Differences. Advance online publication. doi: 10.1016/j.lindif.2018.05.001