20Q: Childhood Apraxia of Speech (CAS): Diagnosis and Treatment

From the Desk of Ann Kummer

Undoubtedly, one of the most fascinating (and also one of the most challenging) communication disorders in pediatrics is Childhood Apraxia of Speech (CAS). Therefore, I am delighted that Amy Skinder-Meredith, PhD., CCC-SLP, an expert in CAS, has agreed to do a 20Q article on this topic!

Dr. Skinder-Meredith is a Clinical Professor and Director of Graduate Studies at Washington State University in Spokane. She is also a very experienced clinician, with a particular interest and expertise in CAS. She has worked in a variety of clinical settings, including a university clinic, public school, hospital, and private practice. She and her colleague, Dr. Nancy Potter, run an intensive two-week camp in the summer for children with CAS and their families. Therefore, Dr. Skinder-Meredith has extensive, real-life clinical experience with this challenging disorder. In addition to her clinical work, Dr. Skinder-Meredith has published research on childhood apraxia of speech (CAS) and presented at many national conferences. As such, we are very fortunate to have her share her knowledge on CAS with 20Q readers.

As we all know, normal speech requires motor movements that are fast, complex, automatic, and effortless. The speaker must coordinate aspects of respiration, phonation, velopharyngeal function and oral articulation—all at the same time. Each complex movement is made in just milliseconds, yet accuracy of placement and timing are critical. Individual movements must then be sequenced for long strings of sounds. All of this is done without conscious thought about where we are placing our articulators or how we are manipulating resonance and airflow for production of each speech sound. When you think about it, it is amazing that most of us are able to produce connected speech at all, and usually at a very early age!

Of course, some children are not so lucky. Children with CAS present with difficulties in various aspects of speech sound production. This could involve difficulty in coordination of the subsystems of speech for single sound production and/or sequencing of movements for connected speech.

This 20Q article provides some key facts regarding the common characteristics of CAS and how CAS can be differentiated from dysarthria or a phonological delay or disorder. Dr. Skinder-Meredith offers very useful tips regarding when and how a diagnosis of CAS can be made. What is particularly interesting is the list of therapy techniques for CAS that have peer-reviewed research to support them. I think you will really learn a great deal from this article!

Now…read on, learn, and enjoy!

Ann W. Kummer, PhD, CCC-SLP, FASHA
Contributing Editor 

20Q: Childhood Apraxia of Speech (CAS): Diagnosis and Treatment​

1. What is childhood apraxia of speech (CAS)?

 According to the ASHA 2007 technical report, CAS is defined as: 

“Childhood apraxia of speech is a neurological childhood (pediatric) speech sound disorder in which the precision and consistency of movements underlying speech are impaired in the absence of neuromuscular deficits (e.g., abnormal reflexes, abnormal tone). CAS may occur as a result of known neurological impairment, in association with complex neurobehavioral disorders of known or unknown origin, or as an idiopathic neurogenic speech sound disorder. The core impairment in planning and/or programming spatiotemporal parameters of movement sequences results in errors in speech sound production and prosody. “(American Speech-Language-Hearing Association. (2007). Childhood apraxia of speech [Technical Report]. Available from www.asha.org/policy. p. 3-4)

2. In this definition, it says CAS is neurological, but in the absence of neuromuscular deficits. Does this mean that a child with CAS cannot have dysarthria?

Not exactly. CAS can certainly co-occur with dysarthria. I have seen this surprise many SLPs. When we learn about motor speech disorders we often focus more on acquired dysarthria in adults and we run out of time to appropriately address developmental dysarthria. Hence, it doesn’t seem to be on our radar when assessing our more complex kids. My colleague, Dr. Nancy Potter, and I have observed that after the motor sequencing has improved, we sometimes notice an underlying dysarthria. In other words, the articulation is weak and imprecise in general, but most phonemes are there and in the right order. 

3. How do we differentiate CAS from developmental dysarthria then?

A structural-functional exam can assist the therapist in determining if there is a dysarthric component. All subsystems need to be assessed to make sure there is adequate breath support, phonatory control, and articulatory movement for speech. A motor speech exam, which assesses sounds in various syllable shapes, word, and phrase lengths, can be used to determine if the child shows the following key features of CAS.

• Inconsistent errors on consonants and vowels in repeated productions of syllables or words.
  • E.g., ogi, tu-i, ku-i for ‘cookie’
• Inappropriate prosody, especially in the realization of lexical or phrasal stress.
• Lengthened and disrupted coarticulatory transitions between sounds and syllables. (ASHA, 2007; Caspari, 2007)

4. Can a child with CAS also have a phonologic disorder or delay?

Yes! Hence, the third area that should be assessed is expressive phonology. If the child has enough speech, they can be given a standardized articulation assessment to look for consistent speech sound error patterns to see if there is a phonological component, as well. I use the Diagnostic Evaluation of Articulation and Phonology (DEAP) (Dodd., Hua, Crosbie, Holm, & Ozanne,2006) or the Goldman-Fristoe Test of Articulation-3rd Edition (GFTA-3) (Goldman, & Fristoe, 2015) with the Kahn-Lewis Phonological Analysis-3rd Edition (KLPA-3) (Kahn & Lewis, 2015), but others prefer the Clinical Assessment of Articulation and Phonology-2nd Edition (CCAP-2) (Secord & Donahue, 2013) or the Hodson Assessment of Phonological Patterns-3rd Edition (HAPP-3) (Hodson, 2004).

5. What is the typical communication profile for a child with CAS?

Every child with CAS is unique. My mentor, Dr. Edythe Strand said it best, we need to look at the relative contribution of each factor that impacts the child’s communication. We can add language to the equation as well. Hence, receptive and expressive language should also be assessed.

6. Are there any other speech characteristics that are common for kids with CAS?

Yes, their speech is also characterized by:

1. Groping or silent posturing for the correct articulatory placement
2. Intrusive schwa (gəreen for green; manə for man)
3. Voicing errors, especially pre-vocalic voicing errors, which could be due to the coordination of voice onset time and the difficulty of quickly going from voiceless to voiced in a CV syllable shape.
4. Slow rate when attempting correct articulatory accuracy
5. Slow diadochokinetic rates (slow DDK), especially on the more posterior sounds and when going from AMRs (e.g., pa-pa-pa) to SMRs (e.g., pataka or patticake)
6. Increased difficulty with longer or more phonetically complex words (i.e., /aI/ may sound ok in isolation, but when put into a CVC, may become simplified, such as /bak/ for /baIk/.)

*Not all of these characteristics need to be present to be diagnosed with CAS.

7. Can you be more specific about characteristics of developmental dysarthria?

The following characteristics can be seen in developmental dysarthria:

1. Scanning speech (pause between syllables)
2. Equal stress  
3. Sound distortions     
4. Irregular diadochokinetic rate (ataxia)
5. Slow rate
6. Reduced range of motion
7. Reduced strength of articulatory contacts
8. Reduced respiratory support or respiratory incoordination
9. Strained or breathy phonatory quality
10.  Adventitious movement (involuntary movement) (Shriberg, Potter, & Strand, 2009)

*Not all of these characteristics need to be present to be diagnosed with dysarthria. For additional information, Hammer & Stoeckel (2006) provide a comparison chart to help differentiate CAS, dysarthria, and severe phonological disorder.

8. Do any of these dysarthric characteristics overlap with CAS?

You may notice that two of these characteristics can overlap with CAS, so this is where it can get tricky. The child with apraxia also tends to have equal stress patterns and slow rate of speech, but it is more noticeable when they are saying something intentionally. In other words, the effort required for correct articulation flattens the natural intonation contour and decreases the rate of speech. If they are speaking without too much attention to their articulation, their prosody tends to be more typical. Hence depending on the concentration needed for the speech task, prosody and rate will vary. Children with dysarthria are more consistent and may improve both prosody and articulation when they increase volitional effort. Also, when it comes to rate, decreased rate will be evident in both speech and non-speech movement.

9. I’ve heard that kids with CAS can also have difficulty with literacy. Is that true?

Yes, and this has been well supported in the literature (Lewis, Freebairn, Hansen, Iyengar, & Taylor, 2004; McNeill, Wolter, & Gillon, 2017: Moriarty & Gillon, 2006; Nathan, Stackhouse, Goulandris, & Snowling, 2004; Snowling, Goulandris, & Stackhouse, 1994). The ASHA Technical Report (2007) summarized research that show children with CAS are at risk for deficits in the following areas:

• rhyming (producing and identifying rhymes)
• word attack, word identification, and spelling
• phonological perception
• phonological discrimination
• phonological memory

10. Does this mean we should be assessing phonological awareness skills, as well? If so, how do you recommend we go about this?

Yes, if the child is old enough. The Comprehensive Test of Phonological Processing-2nd edition is for clients between the ages of 4 and 24-11 (Wagner, Torgesen, Rashotte, & Pearson, 2013). However, most phonological awareness assessments are for children between ages 5 and 9 years. It can also be helpful to look at the English Language Arts Foundational Skills from the Common Core Standards and talk with the teacher to see if the child is where they need to be. (http://www.corestandards.org/ELA-Literacy/ )

11. Do children with CAS have difficulty with anything else?

They may also have soft neurological signs, such as fine and gross motor incoordination, difficulties with gait, and alternating repetitive movement (Peter & Stoel-Gammon, 2008). It is not uncommon for these children to also be receiving occupational therapy and physical therapy, in addition to speech therapy. Sensory processing may also be an issue (Newmeyer et al., 2009; Nijland, Terband, & Maassen, B., 2015). I like to keep this in mind when doing speech therapy. For example, if a child is having a hard time focusing, I’ll set up my session in a way that the hypo- or hyper-sensitivity to certain stimuli is not distracting them from the speech task.

12. Can you give a couple examples of how you accommodate for sensory issues?

I start with the basics, such as making sure the child has good seating, allowing their feet to firmly be on the floor for seated activities. I also incorporate movement into the session. If they need deep input, I have them carry a heavy item from activity to activity. I may also have them form a bridge with me by pressing against their hands and leaning towards each other. This way I have their attention to my face while giving them input into their arms, hands, and shoulders. If they are hypersensitive to things like tags and sock linings, I suggest tag less shirts and lining free socks, or just turning these items inside out. For calming, I put the stimuli in a bucket of beans the child must dig for. Learn-With-Yoga ABC Yoga Cards for Kids (Ristuccia, 2010) and The Out of Synch Child (Kranowitz, 2005), in addition to conversations with your occupational therapist will provide you with many more ideas. Having a visual schedule and having a routine is also helpful.

13. At what age can you reliably diagnose a child with CAS?

That really depends on the child and the characteristics they present at the time. Motor speech assessments are geared more towards children age three and up. However, Overby and Caspari (2015) and Davis & Velleman (2000) reported diagnostic characteristics observed in infants and toddlers with suspected CAS, which helps us be more sensitive to how the disorder may present in a younger child. The therapist may need more time for a dynamic assessment and treatment before feeling comfortable stating whether the child has CAS or not. Options to stating CAS include ‘suspected CAS’ or ‘unable to rule out CAS at this time.’ If you believe the child does have CAS, be sure to list your evidence. For example, what symptoms does this child present that allow the SLP to differentiate from other disorders? Did you observe the following characteristics?

• *Limited repertoire of consonants and vowels
• *Limited canonical babbling
• *Limited word shapes
• *Oral motor coordination
• Consistency of errors?
• Presence of vowel errors?
• Disordered prosody?
• Increased errors on increasing length of utterance?
• Groping?
• Difficulty sequencing sounds and syllables?

*Characteristics observed in infants and toddlers with suspected CAS (Davis & Velleman, 2000)

Also, what characteristics rule out other possibilities?  For example:

• Structures have adequate range of motion, speed, strength, and coordination for speech
• Child has receptive language skills that are WNL or they’re at least higher than expressive language skills.
• Errors don’t just fit a consistent pattern as they would for a child with a phonologic delay.

14. After reviewing these characteristics, I feel like I have a kid on my caseload with CAS. Now what? Where do I start?

Your starting point will be based off your motor speech exam results. Pay attention to syllable shape, word length, phrase length, and sound repertoire, the child could produce with and without support. By support, I mean, could the child produce the target if you decreased the rate, said the word or phrase simultaneously, and/or if you added tactile cues? Since we want to build on success, pick phrases that the child is capable of with some support. Also chose words and phrases that the child will functionally use, so that it is motivating. It takes a lot of effort for children with CAS to speak intelligibly. We need to make it worth their effort. We can get a lot of good information from caregivers as to what is motivating to the child and what situations bring on communication breakdowns and emotional upsets. It also helps to have paired phrases. For example, if choosing the phrase, “help me” be sure to also include “I do it” or “I can do it.”  This allows you to ask the question when the child is getting frustrated with a task, do you need help or can you do it?  Also, given that kids with CAS can have difficulties with prosody, it is also a good idea to include questions, such as “May/can I have ____?” When we train only statements, such as “I need a ____” or “Give me a ____,” the child starts to sound demanding and that won’t lead to good social acceptance. For a more comprehensive guide, I highly recommend Fish (2016) Here’s How to Treat Childhood Apraxia of Speech, Second Edition.

15. How many phrases should be targeted?

That depends on the severity of the apraxia. For severe children, we tend to target about 5 functional phrases. For moderate kids, we may target up to 10. (Strand & Skinder, 1999) One needs to keep in mind that CAS is a motor speech disorder, so we use principles of motor learning to teach correct sequencing of sounds and prosody for intelligible speech. One of the most important principles is repetition. Edeal and Gildersleeve-Newman (2011) showed that when there was a high frequency of repetitions (100+ productions in 15 minutes) the child produced better targets with faster acquisition, and had better in-session performance and greater generalization to untrained probes than in the low frequency condition (30-40 productions). However, children did improve in both conditions. Children who are more severe are going to take longer getting the repetitions needed for motor learning to occur. Hence, we start with a smaller number, so that they can achieve success more quickly.

16. Which therapy techniques for CAS have peer reviewed research to support them?

Murray, McCabe, and Ballard’s (2014) systematic review of treatment outcomes for children with CAS provided support for dynamic tactile temporal cuing (DTTC), rapid syllable transition treatment (ReST), and integration of phonological awareness into speech therapy. There has also been research to support PROMPTS for Restructuring Oral Muscular Phonetic Targets (PROMPT) (Hayden, Namasivayam, & Ward, 2015; Namasivayam et al., 2013). Not every effective treatment technique has published research to support it yet. Hence, it is good to look at the principles most often suggested being important to the treatment of childhood apraxia of speech.

1. Use of intensive paired auditory and visual stimuli.
2. Production of sound combinations versus isolated phoneme training. 
3. Focus on movement performance drill.
4. Use of repetitive production and intensive systematic drill.
5. Careful construction of hierarchies of stimuli.
6. Use of decreased rate, with proprioceptive monitoring.
7. Use of carrier phrases.
8. Use of pairing movement sequences with suprasegmental facilitators such as stress, intonation and rhythm.
9. Establishment of a core vocabulary (especially for the nonverbal child). (Strand & Skinder, 1999)

17. What techniques do you primarily use?

Dr. Edythe Strand, creator of dynamic tactile and temporal cuing (DTTC) (Strand, et al., 2006), was my dissertation advisor, so I have been trained and am most comfortable using this technique. I also use some of the tactile cues I’ve learned from PROMPT and I integrate phonological awareness as outlined by Dr. Gillon and her colleagues’ research. DTTC is outlined as follows:

1. Therapist says utterance while child watches clinician’s face and child repeats
   • if child is unsuccessful, move to simultaneous production, adding tactile or gestural cues as necessary
   • maintain auditory and visual stimuli for repetitions
   • continue until child can easily produce the utterance with therapist
   • fade cue by reducing volume, reducing tactile/gestural cues
2. Immediate repetition
   • therapist says target utterance 
   • child repeats (therapist mouths utterance if additional support is needed, then fades)
3. Addition of delay
   • therapist says target utterance
   • insert 1-3 second delay before prompting imitative response
   • after child is successful in 2-3 second delay, prompt to repeat target several times without intervening stimuli
4. Elicit utterance spontaneously

The hierarchy is constantly changing as the therapist adds or fades cues, depending on the child’s responses. This can be used in addition to other techniques as well. (Strand, et al., 2006)

18. How do you incorporate phonological awareness?

I provide feedback on speech errors that I learned from Gillon (2004) and utilize graphic letters, Phonic Faces by Jan Norris (elementory.com). I use these characters to teach letter sound awareness and provide specific feedback and cuing for speech production. For example, Peter Pops P pops his lips to make the /p/ sound, Elton L lifts his tongue to make the /l/ sound, and Miss A smiles to make the /e/sound. In addition to having the child look at my face, I have them look at the sequence of letter sounds needed to make the word. If they leave out the /l/, I state, “Oops, where did Elton’s /l/ go? Don’t forget to lift your tongue for /l/ or the word is ‘pay.’ It is also helpful for substitutions. Many kids with CAS have a reduced phonemic repertoire and make pre-vocalic voicing errors. Hence, /d/ is a pretty popular substitution for /t/ and /s/, as /b/ is for /p/. This could be due to motor simplification and/or faulty phonemic perception. When the substitution error occurs, I find the character for that sound and talk about how bossy he or she is. This way it isn’t the child’s fault for making the error. It’s the bossy sound’s fault. For example, if the child says ‘dop’ for ‘top,’ I can respond with, “Oh that bossy Dedra D came in and took over Tina Taps ‘t’! Let’s try being very quiet so we don’t wake up Dedra. Ready, let’s whisper ‘top.’ The child says ‘top’ and we are very excited because we let Tina Taps say her sound and didn’t let bossy Dedra take over. Similarly, I use the vowel characters to show them their vowel errors. I had a child who would say ‘uh’ for /a/, as in ‘dolls.’ We talked about the bossy character who made the ‘uh’ sound and we wouldn’t let her in. I also make use of the Lindamood & Lindamood (2011) vowel circle to show how far open the mouth should be and how far the lips need to be rounded or retracted to create that vowel. Basically, it comes down to pairing the grapheme with the phoneme to provide feedback. When we do this, the child gets to improve their early literacy skills, while getting additional cues for how to motorically sequence the sounds in a word or phrase. Mind you, there are many programs and tools available to incorporate phonological and phonemic awareness. Phonic Faces and the Lindamood programs are simply the ones I am most familiar with.

19. How do you know which phonological awareness program to use?

Like CAS, there are basic principles that are important, such as the program being multimodal (e.g., use vision, touch, audition, etc.), systematic, and hierarchical.

20. This work looks intense. Should kids with CAS only be getting one-on-one therapy?

Granted, for a child to produce multiple repetitions of each target phrase with the clinician adding and fading of cues as needed for motor learning to occur, a one-on-one session is beneficial. Also, it should be meaningful and fun (Fish, 2016). However, these children also typically need help in language, pragmatics and literacy. To work on these skills, group therapy in addition to a push-in model, is beneficial, as it provides a more naturalistic environment for communication to occur. Hence, children with CAS should receive both group and individual speech language therapy.