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Childhood apraxia of speech


CAS is a complex problem, so much so that there are endless books, theories, research projects, websites and opinions. I am not sure that there is even a real category that we can comfortably see as “apraxia”, because the criteria for deciding on whether a person has CAS or not are poorly defined. Nevertheless, CAS  is used a lot, and so on this page I will explain what it is.  My main point is that no matter how it is defined, and no matter who is identified  as “having CAS”, every individual is different and there is no one approach to the management of CAS.

What is childhood apraxia of speech?
CAS is a neurodevelopmental problem that interferes with the child’s ability to program the sounds and their sequences. There is no spasticity or low muscle tone, and there is no muscle weakness.

Childhood apraxia of speech is also known as “developmental apraxia of speech”, “verbal apraxia” or “verbal dyspraxia”. 


CAS starts in early childhood and first becomes apparent when children begin to talk. It is not developmental because children do not grow out of it. Without intervention, and even sometimes despite good intervention,  CAS persists. It can improve a lot, but it may not.   The problem is with “praxis”, which is the planning of the movements of speech.

What do we mean by praxis?

Speech starts with an idea. We think about what we want to say. Then we find the words that we need and access the grammatical structure of the sentences that we wish to say. Then we structure the order in which we want our sentences to be. We also coordinate all of this with selecting the sounds that need to be produced, the order in which they need to be said, and we plan the speed and timing of our movements. The muscles of the voice box (larynx), the soft palate, the throat (pharynx), the tongue, jaw, cheeks and head then get information about how to move. All of this happens extremely quickly.  Producing speech, then, is incredibly complex. The praxis part of this complex process is the planning of speech movements, and this is what is difficult for children with CAS.


It is clear that CAS is a neurodevelopmental problem that interferes with the child’s ability to program the sounds and their sequences. There is no spasticity or low muscle tone, and there is no muscle weakness. We are not sure that it is a coordination problem. However, children with CAS can also have low muscle tone as well.

The main features of CAS are as follows:
1. A limited sound repertoire.

Children with CAS do not have many speech sounds to use so they often only use simple syllables like "da"  to stand for everything. Many cannot say all the vowels of their home language. They make vowel errors, and vowels can be distorted.

2. Speech is inconsistent.

For instance, the child may be able to say a /p/ sound at the beginning of words as long as the /d/ is followed by an /e/, yet, he may not be able to say it if followed by an /o/. Or, maybe he can only say a /d/ at the beginning of a word if the word also ends in a /d/ as in 'dad'. Another example could be that the child can say a /d/ word just fine by itself, but if there is a /d/ word in front of it, the /d/ becomes a /t/( so ' dad dog' is said as 'dat tog').

Some errors are idiosyncratic - totally unpredictable and sometimes they are so different that we cannot transcribe (write) them.

3. Speech deteriorates under complex conditions.

Often, speech deteriorates when the complexity increases. Usually, the longer the utterance, the worse the speech accuracy. the child may be able to say a sound alone or not in a word; or in a word but not in a phrase.


For example, a child may be able to say all his 'd' words, but as soon as he puts 3 words or more in a sentence, he drops all the final consonants in his words. Another example is when a word is complex in terms of its phonetics (sound make-up) (e.g. 'spaghetti';' interesting'). 

4. Imitation is better than spontaneous speech

Children with CAS usually have less difficulty saying over-learned words or modeled words as compared to novel words. Sometimes they can imitate you but cannot produce the word by themselves.

5. The rhythm of speech is disturbed.

The rate of speech is often slow. The timing of sounds and the time between syllabes is problematic. Speech sounds choppy or uneven.It can also sound monotonous.

6. Groping.

Some children with CAS seem to struggle to find the right position of the tongue, jaw or lips to say the words. The look like they are struggling to speak.

7. Loss of words.

Some children with CAS develop sounds or words and then lose their ability to say those same sounds or words.

8. Poor speech intelligibility.

Speech is unintelligible some or all of the time. Even familiar partners may have difficulty understanding the child because of the inconsistencies and severity.

9. Anxiety makes it worse.

Most of us have a hard time speaking under stress. The ability to retrieve the motor plans for speech  is affected by stress and anxiety.

10. Babbling may be absent or infrequent

Often children who have CAS did not babble at all or did not babble much. They often do not reach the stage of canonical babbling at 9 to 10 months of age (a stage when babbling starts to sound like real speech


What causes CAS?

At this juncture, we do not know what causes childhood apraxia of speech. It seems that there might be a genetic  factor in some families, but this is not the case for most children with CAS.

Speech therapy and CAS


  • The earlier speech therapy starts, the better the outcomes

  • There are a wide variety of approaches to CAS. No one approach suits every child.

  • Research shows that intensive speech therapy is most effective because children with CAS require regular motor practice

  • Traditional articulation therapy does not work for CAS

  • There is no quick fix and therapy can be required for a long time. Some children with CAS have been in therapy for 4 to 5 years.

  • Some CAS can be very severe, and children might not be able to communicate verbally. For these individuals, alternative and/or augmentative communication may be the best option.


Pre-made, commercially available programs and CAS

There are a number of pre-made programmes that various speech therapists have designed (e.g. Kaufman apraxia programme; EZ Speech; PROMPT, Talk Tools; Articulation cues). The programmes are based on different theories of speech production and on different theories of what causes and maintains apraxia of speech.


Not all speech therapists have access to all of these programmes and in South Africa, we often do not have the training available by the specific developers of the different programmes.


HOWEVER, in South Africa (and probably in many other places where the training of speech therapists is excellent), we are trained - and continue to teach ourselves through our reading and participation in workshops, conferences and courses - on the THEORY underlying the various approaches. As a result, we are able - easily - to create our own programmes that are based on the SAME underlying theories as the commercially available programmes. Furthermore, we often ELECT to avoid the use of commercially available programmes because we design our therapy to suit the INDIVIDUAL client's needs ... sometimes programmes simply do not fit with our patient's needs

Is CAS a diagnosis?

There is no consensus here but I have a very strong opinion that is based on my clinical experience as well as my knowledge of the underlying neurology and motor learning theory.

CAS is absolutely not a diagnosis. It is a term given to categorise a set of behaviours.

CAS is associated with a range of other problems. Many, many individuals who have been diagnosed as "autistic" present with CAS; many many individuals who have language learning problems also present with CAS; many, many individuals who have motor coordination problems have CAS; many children with CAS are low functioning in terms of cognition, yet other do not have any cognitive problems.

Prof Edythe Strand given an excellent talk on CAS. here's her video:

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