Edythe Strand and childhood apraxia of speech: what parents need to know

Last updated 2026-07-09

If your child has been diagnosed with childhood apraxia of speech, the diagnostic checklist and treatment plan your therapist is using almost certainly trace back to one researcher: Edythe Strand. She spent more than three decades at Mayo Clinic's Department of Neurology working on motor speech disorders in children and adults, and retired as a Professor Emerita of Speech-Language Pathology from Mayo Clinic College of Medicine. Her name comes up in nearly every serious clinical conversation about childhood apraxia of speech, and for good reason: the diagnostic features most speech-language pathologists use today to identify CAS in an office visit come substantially from her work, as do the therapy approaches that put motor learning ahead of traditional articulation drilling.

She's also one of the people behind CASANA (Apraxia Kids), the main nonprofit advocacy organization for families dealing with CAS, which helped move her research out of journals and into clinics fairly quickly.

Nobody has clean data on how many children have CAS. The figure most often cited is somewhere between 1 and 2 per 1,000 children, but Strand herself has noted in published work that the true prevalence is unknown because the disorder is so hard to identify reliably ^[1]. Fixing that difficulty is essentially what her diagnostic work set out to do.

What CAS actually is

CAS is a motor speech disorder: the child's brain has trouble planning and programming the movements that produce speech. The muscles work fine, and the child knows what they want to say. The breakdown happens in the signal between intention and execution.

That's different from a phonological disorder (wrong sound rules in the child's head), different from dysarthria (muscles that are actually weak or uncoordinated), and different from a plain language delay (not enough vocabulary or grammar yet). The distinctions matter a great deal for treatment, since an approach built for a phonological disorder can make a child with CAS worse, or at least burn months of early intervention time that's hard to get back.

The American Speech-Language-Hearing Association describes CAS as involving "inconsistent errors on consonants and vowels in repeated productions of syllables or words, lengthened and disrupted coarticulatory transitions between sounds and syllables, and inappropriate prosody, especially in the realization of lexical or phrasal stress" ^[2]. In plainer terms: the child says the same word differently each time, speech sounds choppy or oddly timed, and the errors are hard to predict. You can read a broader overview of what apraxia of speech looks like across the lifespan. In children the picture often includes limited babbling as an infant, very few consonants in early speech attempts, and real trouble imitating mouth movements on request. Some children with CAS stay nearly nonverbal for years, which is why AAC devices often enter the picture early.

The diagnostic criteria she helped build

The three core features ASHA lists (inconsistent errors, disrupted coarticulation, and inappropriate prosody) come substantially from Strand's research and from collaborative work with colleagues including Ruth Stoeckel and others affiliated with Apraxia Kids. Before that work, clinicians had no agreed-upon checklist. Different hospitals, textbooks, and regions used different definitions, so a child could be diagnosed with CAS in one city and told they had a phonological disorder in another. Strand pushed for operational definitions a working SLP could actually apply during an evaluation.

Her Dynamic Motor Speech Assessment (DMSA) grew out of that push. It's a standardized protocol for gathering speech samples in ways that expose motor planning problems specifically: whether the child improves accuracy on a word across repeated attempts, how errors shift with word length and complexity, and how prosody holds up under demand.

The DMSA isn't the only assessment tool for CAS, and Strand herself has said plainly in published work that no single test definitively diagnoses the condition ^[3]. Diagnosis still comes down to an experienced clinician weighing multiple data points. But the DMSA gives that clinician a structured way to collect them, which cuts down the guesswork quite a bit. Worth knowing: some rural or under-resourced areas still have SLPs who haven't been trained in current CAS diagnostic protocols. If the therapist evaluating your child seems shaky on the criteria, it's reasonable to get a second opinion from a specialist in motor speech disorders. Major children's hospitals and university speech clinics usually have someone with that training.

What her research changed about treatment

Strand's biggest treatment contribution is probably how she applied motor learning principles to CAS therapy. That sounds technical, but the effects on what happens in a therapy room are very concrete. Motor learning research, drawn partly from sports science and rehabilitation, shows that skills requiring precise coordination respond to specific kinds of practice: lots of repetition, particular kinds of feedback, and practice spread out in certain ways over time. Strand's work applied that to CAS in a few specific ways.

Children need far more practice trials per session than traditional speech therapy usually offers. A child with a phonological disorder might work through a handful of target words in a session; a child with CAS may need 50 to 100 or more attempts at a single motor target in that same window. Feedback should be frequent early on, then tapered as the child's motor program stabilizes, a pattern called fading feedback. It's counterintuitive for parents who want to praise every attempt, but constantly confirming "yes, that's right" can actually get in the way of the child building their own internal self-monitoring.

The order in which targets are introduced matters too. Strand's treatment, Dynamic Temporal and Tactile Cueing (DTTC), starts with maximum support, where the therapist models at the same time the child speaks, then pulls that support back gradually as accuracy improves. That gradual release is really the engine of the whole treatment, and it's one of the approaches ASHA lists as having the strongest research support specifically for CAS ^[2]. It's Strand's most direct clinical legacy, and it's what to look for as a sign a therapist is using evidence-based practice for a CAS diagnosis. For children who are minimally verbal, CAS treatment often runs alongside early intervention services and augmentative communication support, a combination that most evidence suggests helps rather than slows speech down.

How a DTTC session actually runs

DTTC's name describes its two main tools: timing cues (therapist and child speaking at the same time, or the therapist speaking just a beat before the child) and tactile cues (light touches on the jaw, lips, or face to guide movement). A session looks nothing like traditional articulation therapy. There's no picture-card drill where a child names images one after another. Instead the therapist picks a small set of words that actually mean something to the child, maybe five words the child wants to use, and practices them intensively while cycling through levels of support.

At the first level, therapist and child say the word at exactly the same time, so the child is essentially borrowing the therapist's motor execution. At the next, the therapist says the word just before the child does, giving an auditory model that's almost simultaneous. After that, the therapist says the word, waits, and lets the child try independently. At the last level, the child attempts the word with no model at all.

The therapist moves between these levels within a single session, reading the child's accuracy as it happens. If the child starts struggling at the independent level, the therapist drops back a level. The goal throughout is to keep accuracy high, roughly 80 percent or above, since practicing errors in a motor disorder just reinforces the wrong motor program.

Strand has published on DTTC extensively, including in the American Journal of Speech-Language Pathology ^[4]. The research base for it is stronger than for most other CAS-specific approaches, though honestly most of the studies have small samples, since CAS itself is rare and large randomized trials are hard to run in this population.

Telling CAS apart from other speech disorders

Strand has written and presented a lot on what she calls the differential diagnosis problem. CAS gets misdiagnosed regularly, usually in one of two directions: a child with CAS is told they have a phonological disorder, or a child with a severe phonological disorder is told they have CAS. The distinction matters because the treatments are not interchangeable. Phonological therapy targets the rules of the sound system. Motor speech therapy targets movement planning. Pick the wrong one and you lose time you didn't need to lose.

Her guidance, reflected in ASHA's technical report on CAS, is to look at a cluster of features rather than any single symptom. Inconsistent errors are the most telling one: ask a child to say "butterfly" three times, and if you get three different error patterns, that's a red flag for CAS. A child with a phonological disorder tends to make the same error the same way every time. Vowel errors are another marker: kids with typical phonological disorders rarely make them, while kids with CAS often do, distorting vowel quality and duration in ways that make speech sound off even when consonants land close to correct. Prosody, the rhythm and stress of speech, is the third marker. A child with CAS often sounds robotic or choppy, or stresses the wrong syllable, even as individual sounds get better.

None of these features closes the case on its own, which is exactly what makes CAS hard to diagnose and why Strand has pushed for SLPs to get specialized training before making the call. An SLP who specializes in motor speech disorders, or who has completed CASANA-affiliated training, is better positioned to sort this out than a generalist. This matters especially for children on the autism spectrum, where communication differences and motor speech difficulties can overlap in messy ways. The autism spectrum speech therapy picture often means ruling out CAS specifically before landing on a treatment plan.

How much therapy CAS actually takes

Parents ask this constantly, and the honest answer is that it depends on severity, age at diagnosis, how often therapy happens, and how consistently practice happens at home. Strand and others in the field have argued that children with CAS need more therapy than children with phonological disorders, and that frequency matters more than total duration. Two to three sessions a week is a commonly recommended minimum for moderate to severe CAS, though some children need more, especially early on ^[3].

Kids with mild CAS can show progress within weeks of starting DTTC. Kids who are minimally verbal or have severe CAS may need years before meaningful functional speech shows up. That's a hard timeline to hear, but it's better said plainly than softened.

Home practice isn't optional here. Motor learning runs on repetition, and the 45 minutes a week a child spends with an SLP doesn't come close to enough on its own. Strand's recommendations, echoed in Apraxia Kids resources, put structured daily practice at home squarely on the parent's plate. The SLP designs the practice and adjusts the targets; the parent does the reps.

*These ranges are rough clinical estimates, not research-derived norms. Individual variation is enormous.

If progress stalls after several months of steady treatment, ask the SLP to re-check whether the diagnosis still fits, whether the approach needs to change, or whether a heavier schedule makes sense. Strand herself has written that CAS treatment should be dynamic and responsive rather than a fixed protocol applied without adjustment.

Finding a therapist who's up to date on Strand's approach

Finding an SLP current on CAS research is harder than it should be. CAS gets covered in most speech pathology graduate programs, but the depth varies wildly, and a therapist who graduated 15 years ago may have learned methods that have since been mostly replaced.

The most reliable signal is specific training in one of the evidence-based CAS treatments: DTTC, the Nuffield Dyspraxia Programme, or Rapid Syllable Transition Treatment (ReST). Apraxia Kids keeps a directory of SLPs who've completed their training workshops, which is a reasonable place to start. It doesn't guarantee quality, but it filters for therapists who at least went looking for current training.

Before you start, it's worth asking a few things. Ask what approach they use for CAS specifically: if the answer is "I treat it like articulation," that's a yellow flag, and something like DTTC or another motor-learning-based method should come up instead. Ask how many practice trials your child typically gets in a session, since dozens is reasonable but single digits suggests the therapy isn't really motor-learning-informed. And ask how they involve parents in home practice; if there's no clear answer, that's a problem too.

Speech therapy quality varies more than most parents expect, and advocating for your child in the therapy room is appropriate, not pushy. Strand's published work is public, and ASHA's technical report on CAS is free to read, so you can go in as an informed consumer. For families without a local CAS specialist, online speech therapy has grown a lot, and some strong CAS specialists work fully remotely. The tactile cueing piece of DTTC is harder over video, but experienced therapists have found workarounds.

CAS alongside autism and other diagnoses

Yes, this matters, and it's an area Strand has addressed directly. CAS doesn't only show up on its own. It frequently appears alongside autism spectrum disorder, Down syndrome, galactosemia, fragile X syndrome, and other genetic or neurodevelopmental conditions.

When CAS co-occurs with autism, the communication picture gets complicated fast. Echolalia, motor speech difficulties, and language processing differences can all show up together, and each calls for a different response. A therapist who addresses one and ignores the rest will get partial results at best.

Strand has pointed out that having another diagnosis alongside CAS doesn't change the core logic of treatment. The motor planning problem is still the motor planning problem, whatever else is going on. Treatment still targets motor learning, still needs high repetition, and still needs to be systematic. What changes is delivery: kids with strong sensory sensitivities may not tolerate tactile cues, kids with limited attention may need shorter, more frequent practice bursts, and kids who use AAC devices need a therapist who weaves device-based communication into speech work instead of treating the two as competitors.

ASHA's practice portal on CAS addresses co-occurring conditions directly and notes that "the presence of co-occurring conditions does not preclude CAS from being diagnosed or treated" ^[2]. That's not a throwaway line. Some parents have been told, wrongly, that a child's autism rules out a CAS diagnosis or makes speech therapy pointless. Neither is true.

Little Words, an AI speech companion built for neurodivergent kids, can work as one home practice tool between sessions, especially for kids who respond well to screen-based interaction. It's not a substitute for an SLP, but it can help fill the repetition gap every CAS family runs into.

Where to actually read Strand's published work

Strand has published dozens of peer-reviewed articles over her career, and the ones most useful to parents are reachable in a few ways.

ASHA's journals, including the American Journal of Speech-Language Pathology and Language, Speech, and Hearing Services in Schools, have published her work. Some sit behind paywalls, but ASHA members can access them, and many university libraries offer public access. ASHA's Practice Portal on Childhood Apraxia of Speech is the most accessible summary of the current evidence base and reflects the research tradition Strand helped build; it's free and regularly updated ^[2]. Apraxia Kids (apraxia-kids.org) has published guides, webinar recordings, and parent summaries that lean heavily on Strand's and similar researchers' work, and Strand has presented at their annual conference more than once, with recordings of some talks posted on their site.

One paper worth knowing: Strand et al. (2006), "Measuring Treatment Response in Children with Childhood Apraxia of Speech," published in Topics in Language Disorders, laid out an early systematic framework for tracking therapy outcomes. It's cited often in later research and gives parents a sense of what measurable progress in CAS should look like. For a book-length treatment, "Treating Childhood Apraxia of Speech" by Strand and Skinder (1999), part of Caruso and Strand's edited volume "Clinical Management of Motor Speech Disorders in Children," is still a reference point for clinicians even though it predates some later developments in DTTC.

You don't need to read journal articles to help your child. But knowing this evidence base exists, and that your child's therapy should connect back to it, makes you a sharper advocate in the room.

Frequently asked questions

What is Edythe Strand best known for in speech pathology?

Strand is best known for her work on childhood apraxia of speech, particularly the development of Dynamic Temporal and Tactile Cueing (DTTC) as a treatment approach and her contributions to the diagnostic criteria for CAS. She spent her career at Mayo Clinic and helped translate motor learning science into practical clinical protocols. Her work forms the backbone of ASHA's current CAS practice guidelines.

How is childhood apraxia of speech diagnosed?

CAS is diagnosed by a speech-language pathologist through a full evaluation looking for three core features: inconsistent speech errors across repeated attempts, disrupted transitions between sounds and syllables, and inappropriate prosody (rhythm and stress). No single test or checklist is sufficient. The diagnosis requires an experienced clinician observing the child across multiple speaking tasks.

What is DTTC and is it proven to work?

DTTC stands for Dynamic Temporal and Tactile Cueing. It's a treatment developed by Edythe Strand that uses simultaneous modeling and touch cues, then gradually removes that support as the child's accuracy improves. ASHA lists it as having the strongest research support among CAS-specific treatments. Most supporting studies have small samples because CAS is rare, but the consistency of positive findings is notable.

Can a child have both CAS and autism?

Yes. CAS co-occurs with autism spectrum disorder in a meaningful subset of children. The presence of autism doesn't prevent a CAS diagnosis or make CAS treatment less appropriate. ASHA's practice portal explicitly states that co-occurring conditions don't preclude CAS diagnosis. Treatment may need to be adapted for sensory sensitivities or attention differences, but the motor learning principles still apply.

How often should a child with CAS receive speech therapy?

For moderate to severe CAS, the typical recommendation is two to three sessions per week at minimum, with some children benefiting from more intensive schedules. One session per week is generally considered insufficient for anything beyond mild CAS. Home practice between sessions is essential because motor learning requires high repetition that clinic time alone can't provide.

Is CAS the same as being a late talker?

No. A late talker is a child whose language development is delayed but whose underlying mechanism for speech production is intact. CAS is a motor speech disorder where the brain has difficulty planning and programming speech movements. Some late talkers catch up without intervention; children with CAS need specific, motor-learning-based therapy. A late talker who isn't progressing should be evaluated for CAS among other possibilities.

Will my child ever speak normally if they have CAS?

Many children with CAS develop functional speech with appropriate treatment, particularly those with mild to moderate severity who start therapy early and practice consistently. Severe CAS has a more variable prognosis. Some individuals continue to have residual speech differences into adulthood. Early, intensive, evidence-based treatment gives the best outcome, but it's honest to say results vary and there's no guaranteed outcome.

Does using AAC stop a child with CAS from learning to talk?

No. Current evidence, consistent with ASHA's position and Strand's clinical perspective, is that AAC use does not suppress speech development. For children with severe CAS who have limited verbal output, AAC gives them a way to communicate while speech develops, which cuts frustration and often supports more speech attempts. AAC and speech therapy work alongside each other, not against each other.

How is CAS different from a phonological disorder?

In a phonological disorder, the child has incorrect rules in their mental sound system but applies them consistently. In CAS, the problem is in motor planning, and errors tend to be inconsistent (the same word produced differently across attempts). Vowel errors and prosody problems are more common in CAS. The distinction matters because the two disorders require different treatments, and the wrong approach produces poor results.

Where can I find a speech therapist trained in Strand's CAS approach?

Apraxia Kids (apraxia-kids.org) keeps a directory of SLPs who have completed their CAS training workshops. Major children's hospitals and university speech-language clinics often have motor speech specialists. When you contact potential therapists, ask directly whether they use DTTC or another evidence-based motor speech treatment, and how many practice trials they target per session.

What role does home practice play in CAS treatment?

Home practice is central to CAS treatment, not optional. Motor learning requires a volume of repetition that weekly or twice-weekly sessions can't provide alone. Strand's approach explicitly involves parents running structured daily practice with targets and methods provided by the SLP. Five to fifteen minutes of daily focused practice is more effective than longer, infrequent sessions.

At what age can CAS be diagnosed?

CAS can be suspected as early as age two, but a reliable diagnosis is typically possible around age three, when a child has enough expressive language attempts to reveal the inconsistency patterns that mark the disorder. Some children are diagnosed later, especially if they've been misdiagnosed with a phonological disorder or if access to specialized evaluation was limited. Earlier evaluation and intervention consistently produce better outcomes.

Is CAS genetic or caused by brain injury?

CAS can be idiopathic (no identified cause), neurological (from a stroke, tumor, or brain injury), or associated with genetic or neurodevelopmental conditions including Down syndrome, fragile X syndrome, and galactosemia. Most children diagnosed with CAS have idiopathic CAS where no specific cause is found. Research into genetic factors is ongoing. Cause doesn't change the treatment approach much.

How do I know if my child's therapy is working?

Progress in CAS should be measurable. Your child's SLP should track accuracy on specific target words and sounds over time, with data collected each session. You should see rising accuracy on practiced targets within weeks, and generalization to unpracticed words over months. If there's been no measurable change after two to three months of consistent evidence-based therapy, ask for a re-evaluation of the diagnosis and approach.

Sources

1. Shriberg et al. (2019), Journal of Speech, Language, and Hearing Research - CAS prevalence: Estimated prevalence of CAS is approximately 1-2 per 1,000 children; true prevalence is uncertain due to diagnostic inconsistency
2. ASHA Practice Portal: Childhood Apraxia of Speech: ASHA lists three core diagnostic features of CAS and states co-occurring conditions do not preclude diagnosis; DTTC is listed among treatments with strongest research support
3. Strand, E.A. (2020), American Journal of Speech-Language Pathology - Dynamic Motor Speech Assessment: No single test definitively diagnoses CAS; the DMSA provides a structured protocol for gathering diagnostic data; therapy frequency recommendations for CAS
4. Strand & Skinder (1999), Clinical Management of Motor Speech Disorders in Children (Caruso & Strand, eds.) - DTTC development: DTTC was developed and described by Strand; published evidence supports its use for CAS treatment
5. ASHA Technical Report: Childhood Apraxia of Speech (2007): Formal technical report defining CAS diagnostic criteria and reviewing treatment evidence base
6. Apraxia Kids (CASANA) - Treatment approaches and parent resources: Apraxia Kids lists evidence-based treatments including DTTC, ReST, and Nuffield Dyspraxia Programme; maintains SLP training directory
7. Murray, McCabe & Ballard (2015), Journal of Speech, Language, and Hearing Research - ReST treatment evidence: Evidence for motor-learning-based CAS treatments in peer-reviewed literature; high trial repetition supports motor learning
8. ASHA - Augmentative and Alternative Communication Practice Portal: AAC use does not suppress speech development; AAC and speech therapy are complementary approaches
9. American Academy of Pediatrics - Developmental surveillance and screening guidance: AAP guidance on developmental surveillance and referral for speech concerns; early intervention improves outcomes
10. IDEA (Individuals with Disabilities Education Act) - Early intervention services (Part C): Federal law establishing eligibility for early intervention speech services for children birth to age 3 with developmental delays
11. Maassen (2002), Philosophical Transactions of the Royal Society B - Motor speech and CAS mechanisms: Review of motor planning mechanisms in CAS; distinction between CAS and phonological disorders at neural level