New review of treatment options for Childhood Apraxia of Speech (CAS)

Researchers at the University of Sydney recently published a nice review of various treatment approaches for Childhood Apraxia of Speech in the American Journal of Speech-Language Pathology.   It isn't the easiest journal to get your hands on here in NZ, so I thought I'd type up my notes from reading the article and share them here.

The quote most relevant to me was:

"The current literature suggests that when a child experienced frustration over low intelligibility or comprehensibility, AAC approaches may increase communicative success as well as stimulate development of language skills that cannot be practiced through speaking." p 16

My personal take home message was that both motor and linguistic treatment approaches show positive outcomes.

Given that I believe that literacy, language and communication skills are paramount to success in school, work, and life and that these skills also support speech development, I will continue to strive to ensure that my clients with CAS have

(a) access to AAC as needed,

(b) are working on literacy and language skills as part of speech therapy, and of course, as always,

(c) encourage speech skills.

The disheartening piece was looking at how much therapy per week was suggested (2-3 sessions per week with at least 60 chances to practice a motor skill per session).  I do hope one day adequate funding will be provided to ensure that is a reality for the children who need it. 

And now more detail on the article for those who are interested:

Introduction:
Murray et al did a nice job reviewing the multiple names used to refer to this developmental disorder:

  • Childhood Apraxia of Speech (CAS)
  • Developmental Apraxia of Speech
  • Developmental Dyspraxia
  • Developmental Verbal Dyspraxia (particularly in the UK)

They also concisely outlined the hallmarks of this condition as described by ASHA in 2007:

  • inconsistency in the speech errors observed
  • transitions between sounds are longer and disrupted
  • Prosody (the intonation, stress, and rhythm of speech) is inappropriate

Always a good reminder that while apraxia is thought of as a disorder of motor planning or motor programming, there are also reports of

"disrupted development of speech perception, language, and phonology (including phonological awareness) in children with CAS (Groenen, Maassen, Crul, & Thoonen, 1996; Lewis et al., 2004; Maassen, Groenen, & Crul, 2003). " p 2

I also appreciated this statement, which not only reminding us of the complexities, but  also that such skills do not develop in isolation from each other:

"It is unclear whether these are primary deficits or flow-on effects from CAS, comorbid  impairments, or perhaps compensatory behaviors, as children with CAS develop their linguistic, phonological, and motor skills concurrently (Alcock, Passingham, Watkins, & Vargha-Khadem, 2000; Marion, Sussman, & Marquardt, 1993; Ozanne, 2005)." p2

Treatment approaches:
Murray et al reviewed published evidecne for three types of treatment:

  1. Motor approaches: specifically working on speech production. Methods included Integral Stimulation with Dynamic Temporal and Tactile Cuing (DTTC), Rapid Syllable Transition Treatment (ReST), articulation with facilitative vowel contexts and others.
  2. Linguistic approaches: targeting phonology, literacy and other language skills that require the ordered use of linguistic units. Examples included Integrated Phonological Awareness Intervention, Melodic  Intonation Therapy (MIT), and Combined Stimulability (STP) with modified core vocabulary.
  3. AAC approaches: ensuring that communication is possible through the use of augmentative and alternative forms of communication. Examples included Aided AAC modeling and the use of voice output devices (now known as speech generating devices)

Findings:
To date this article reported that there are no randomize studies comparing outcomes of these various approaches, so at this time one cannot say that any given treatment is more efficacious than others.

That said, there were several well designed, quasi-experimental studies with evidence suggesting that children with CAS do respond to various types of speech therapy.  Thus, we should feel confident that speech therapy is indeed appropriate for this population.

Further, several approaches demonstrated generalization (i.e., progress seen during therapy  sessions were also seen outside of therapy, which is the ultimate goal really) including:

  • Integral Stimulation/ DTTC  (motor)
  • ReST (motor)
  • Integrated Phonological Awareness Intervnetion (linguistic)
  • Aided AAC modeling (linguistic / AAC - to which I would add inherently has a motor component)
  • Facilitative vowel context interventions (motor)

The top three approaches on this list showed "preponderance" evidence which was defined as:

" A treatment approach was categorized as havingpreponderantevidence when it showed Level IIb or better evidence (SCEDs), replicated cases, diagnostic confidence ratings of 1–3, statistically significant treatment and generalization effects (or at least moderate effect sizes), and clear maintenance of treatment gains at least 2 weeks post treatment. " p 5

Level II = "Well-designed non-randomized controlled trial (quasi-experiments)"  according to ASHA's  2007 policy written by Randall R. Robey.

Future studies may add additional methods to this list and additional insights regarding the relative benefits of various approaches.

References:
 

reviewed article:
Murray, E., McCabe, P., Ballard, K.J., 2014. A Systematic Review of Treatment Outcomes for Children with Childhood Apraxia of Speech. American Journal of Speech-Language Pathology. doi:10.1044/2014_AJSLP-13-0035

Other citations:
American Speech-Language-Hearing Association. (2007). Childhood apraxia of speech [Technical report].  Available from www.asha.org/policy

Robey, R. R. (2004, April 13, Levels of Eveidence. The ASHA Leader. [link]