Common Mistakes When Evaluating for Childhood Apraxia of Speech (CAS) – Part 2
By Breanna Waldrup
In a previous post, I wrote about several evaluation mistakes that I see frequently as an expert in childhood apraxia of speech (CAS). In this post, I’ll discuss a few more missteps to watch out for when evaluating for CAS.
Mistake #6 - Not doing enough speech tasks
The current consensus from researchers and experts in the field is that a diagnosis of CAS should be based upon the presence of CAS-specific characteristics demonstrated across speech tasks. Speech tasks typically refer to different assessments, administered under different conditions and with varying complexity. For example, an articulation test, which is typically composed of primarily one syllable words, during which the child produces the words to label pictures, might be a speech task. The evaluator might also do a speech task in which they elicit words with a variety of syllable shapes and lengths. Depending on the number of words, the one syllable words might be a speech task, the two syllable words might be a speech task, etc. In addition, the evaluator might also do a speech task in which they elicit non-sense words and/or assess diadochokinesis (DDK – “putuku” or “pataka”). In doing these speech tasks, we are looking to see if the child is demonstrating difficulty motor planning and programming for speech, as evidenced by CAS-specific features, across tasks to see a preponderance of characteristics and a pattern across their speech. We want to see what the child is able to do on their own, in their comfort zone, but also what they can do with more complex tasks and at their point of sequencing breakdown. If we do not have enough data, we may miss the presence of CAS. For example, if we only administer an articulation test and the child is familiar/has rehearsed those words or their sequencing breakdown is above two syllables, they may not demonstrate many errors or features of CAS. On the other hand, we can also over diagnose if we only administer tasks that are too motorically and/or linguistically challenging for the child, given their age. For more about this, see Mistake #5 in my previous post.
Mistake #7 - Using Tasks that are Not Novel
The benefit of using novel speech tasks, such as non-sense words, when evaluating for CAS is that it gives the clinician insight into how a child motor plans and/or programs a word for the first time. In doing so, we may see typical errors and/or we may see features of CAS, indicating inefficiency in motor planning and/or programming. If only assess words that the child has practiced, we only gain insight on what their system is able to do for rehearsed/learned/practice words. When I am evaluating a child for CAS, I am almost never the first speech-language pathologist (SLP) that they ‘ve seen, nor is it their first evaluation. Most children being evaluated for CAS have been in speech therapy and have been evaluated previously. It’s not unusual when I am doing the Dynamic Evaluation of Motor Speech Skills (DEMSS) for a parent to comment “We’ve been working on that word in therapy!” While that doesn’t mean we should use words that have been practiced or trained, it does mean that we also need to make sure we are assessing untrained words. If we only assess words that a child has practiced, we are not fully ascertaining their ability to motor plan and program speech.
Mistake #8 - Using static testing only
When I was in graduate school I only recall learning about static testing, since that is what most standardized, norm-referenced tests are. As a quick reminder, standardized tests mean that we administer the tests in a standard manner – when the test was developed, it was done so with a set of directions in how to give it. Norm-referenced means that the test was developed and given to a group of individuals and that was used to determine the average and standard deviations of the test. Most of these tests are static. We administer the prompt, the child responds, we record and score the response, and we move on to the next item. In contrast, dynamic testing means that we administer the prompt, the child responds, then we provide assistance/cues/scaffolding and see how the child responds. Dynamic testing can be done in many areas. For motor speech exams, dynamic testing means that we can provide multisensory cueing to a child to see how their system responds. This provides a lot of information about how flexible or responsive their motor speech system is to cueing, which can inform diagnosis and prognosis. During a dynamic motor speech exam, we can also look for any features of a motor speech disorder that might emerge. Dynamic testing is also testing stimulability, so it gives us information about what goals or targets might be appropriate for treatment. Doing a combination of static testing (what the child can do on their own) and dynamic testing (what the child can do with assistance) is often helpful.
While you can do an informal dynamic motor speech exam, there is one published (formal) dynamic motor speech exam, the Dynamic Evaluation of Motor Speech Skills (DEMSS) which is a standardized, criterion-referenced test that was developed to differentially diagnose CAS from other speech sound disorders. It is not norm-referenced, so it does not compare children to a normative population. Rather, it was designed for children who have already been identified as having a speech sound disorder and the goal is to decide if that disorder is CAS. It is important to note that children with suspected dysarthria were not included in the groups upon which this test was developed, so it is not appropriate for differentially diagnosing between CAS and dysarthria. It’s also important to know that the DEMSS goes from one syllable to three syllable words, so it is only appropriate for children whose level of breakdown is occurring within that level of sequencing. For children who are not able to complete all of the items on the DEMSS or who are experiencing significant difficulty with motor planning and programming speech at three syllables or less, an informal dynamic motor speech exam with speech targets at the appropriate levels is recommended.
Mistake #9 - Not assessing for other motor speech disorders
The last common mistake that I see when evaluating for CAS is a failure to consider other motor speech disorders, namely pediatric dysarthria and speech motor delay. In fact, the only children that I have diagnosed with pediatric dysarthria were all referred due to suspected CAS or came with a diagnosis of CAS. While we do not have a firm set of discriminative characteristics for speech motor delay, I have also seen a number of young children over the years who I believe had speech motor delay. While they exhibited some challenges with motor speech, they did not meet criteria for CAS or dysarthria. At this time, speech motor delay is a diagnosis of exclusion – it is used for children who exhibit motor speech challenges but not meet the criteria for CAS or dysarthria. CAS shares certain features with dysarthria and certain features with speech motor delay. Thus if we are evaluating and not considering those other diagnoses, we will likely misdiagnose the disorder as CAS or potentially erroneously rule-out a motor speech disorder, since we only considered CAS and possibly miss the presence of speech motor delay or dysarthria.
Summary
When we are evaluating for childhood apraxia of speech, we must be careful to make sure that we are:
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assessing for discriminative characteristics of CAS across speech tasks
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not basing a diagnosis of CAS on non-speech movements
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not diagnosing CAS in a child who is not yet speaking
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administering speech tasks that are appropriate for the child’s motor and language levels,
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not ruling out CAS based on the use of phonological patterns
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administering a variety of speech tasks, including novel speech tasks
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using both static and dynamic testing
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considering other motor speech disorders
Speech-language pathologists are the recommended professionals for diagnosing CAS, but only if they have the training, knowledge and competence to do so. This means staying up-to-date with the current best practices grounded in the latest research.
If you’re interested in learning more about evaluating for CAS, be sure to check out the Bjorem and Bolles Foundation training that will be held in July 2026 in Parker, Colorado!
