Childhood Apraxia of Speech - CAS

Childhood Apraxia of Speech, or CAS, is a severe speech disorder found in young children. CAS has several different titles that are currently used. Other names for CAS are developmental verbal dyspraxia, developmental dyspraxia of speech and just simply, dyspraxia.


In my experience, some health professionals don't have a clear understanding of CAS and confuse it with other speech disorders, such as the more common developmental phonological disorder.


A concern is that over the years I have spoken to a number of parents whose children have been given a diagnosis of CAS from health professionals, sometimes after only a brief 20 minute consultation.


It's important to acknowledge that childhood apraxia of speech is difficult to diagnose and often requires several different assessments, observation of the child's speech over time, and quite a bit of expertise from qualified clinicians who understand its distinguishing features. I don't think CAS is something that can be accurately diagnosed in a 20 minute session.


Children with child apraxia of speech have some form of disruption of their speech motor control. It is believed that the impairment lies somewhere between the phonological encoding and the motor planning areas of an individual's speech processing system (Apraxia-KIDS). That is, in typical conversational speech, individuals with dyspraxia will have distorted or even unintelligible speech due to difficulty in rapidly moving their articulators (tongue, teeth, lips) in an ordered and sequenced manner.


It is the combination of motor planning problems and phonological linguistic difficulties which is a distinguishing feature of CAS. However, a recent report (2007) from the ASHA (American Speech and Hearing Association) concluded in fact that, currently, there is no single set of diagnostic features (or standardized tests) that can differentiate CAS from other child speech sound disorders.


However, there was consensus among ASHA committee members that there were three segmental (discrete speech units such as phonemes - vowels and consonants) and suprasegmental (phonemes that are not distinct units of sound that include tone, stress and prosody in connected speech) features that were consistent in children with CAS.


The three features are...

Inconsistent errors on consonants and vowels in repeated production of syllables and words.

lengthened and disrupted coarticulatory (a speech sound influenced by and becomes similar to a preceding or following speech sound) transitions between sounds and syllables.

Inappropriate prosody (the rhythm and stress of speech - affects the form of speech, whether question, statement or command).

The ASHA committee stated that the above features alone are not to be considered as sufficient signs of CAS. This is due to the understanding that each child with CAS, phonological disorder, or both may have a unique profile that will be affected by task complexity, the severity of the child's speech/phonological errors and his/her age.


References

American Speech-Language-Hearing Association. (2007). Childhood Apraxia of Speech (Technical Report) Available from www.asha.org/policy

Apraxia-KIDS website. SLP start guide to Apraxia. Available from http://www.apraxia-kids.org

Bowen, C. (2009) Children's Speech Sound Disorders. Wiley-Blackwell John Wiley & Sons

Ladefoged, P. (1993) A Course in Phonetics, Third Edition. Harcourt Brace College Publishers

Royal College of Speech and Language-Therapists (2011) RCSLT Policy Statement: Developmental Verbal Dyspraxia Available from www.ndp3.org/documents/rcslt2011dvdPolicyStatement.pdf

Williams, L.A. McLeod, S. & McCauley, R.J. (2010) Interventions in Speech Sound Disorders in Children. Paul H. Brookes Publishing Co.

Content Updated 1/12

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