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PediatricCAS

Childhood Apraxia of Speech (CAS)

Childhood apraxia of speech is a rare motor planning disorder characterised by inconsistent error patterns, disrupted prosody, and lengthened coarticulatory transitions.

What CAS is

Childhood Apraxia of Speech is a neurologically based speech-motor planning disorder in which the child has difficulty executing the precise, sequenced movements required to produce speech sounds. It is distinct from dysarthria, which reflects muscle weakness, and from phonological disorder, which reflects a learned rule system. The ASHA technical report on CAS (2007) describes three core features: inconsistent errors on repeated productions of the same word, lengthened and disrupted coarticulatory transitions between sounds, and inappropriate prosody particularly on lexical and phrasal stress. Diagnosis requires the presence of all three features and is made by an SLP with speech motor training.

Prevalence

CAS is rare — estimates range from 1 to 4 per 1,000 children (Shriberg et al. 1997; Hall et al. 1993) — which means most general-caseload SLPs will see only a handful of cases in a career.

Diagnostic criteria and defining features

  • Inconsistent errors on repeated productions of the same word or syllable sequence
  • Lengthened and disrupted coarticulatory transitions between sounds and syllables
  • Inappropriate prosody, especially in lexical or phrasal stress realisation
  • Vowel distortions and groping oral movements on consonant targets
  • Speech motor control impairment rather than phonological or linguistic impairment

Criteria summarised from DSM-5-TR, ICD-11, and ASHA practice guidance. Always cross-reference against the diagnostic manual of record before using in a report.

Clinical presentation

The classic CAS child is a late talker whose expressive vocabulary lags dramatically behind receptive ability, whose attempts at familiar words sound different every time, and whose prosody is noticeably flat or mis-stressed. Vowel errors are a hallmark — typical phonological disorders leave vowels intact, but CAS routinely distorts them. Parents report watching the child "try" — visible groping of the jaw and lips before a word comes out. The child is often frustrated with their own speech and may resist producing novel words even when encouraged. Diagnosis should never be made from a single session; variability and prosody are best judged across repeated observations.

“If the same child says "banana" three different ways in five minutes — not as developmental refinement but as three unpredictable attempts — and the vowels are distorted, CAS is on the differential. Vowel errors are the tell that separates CAS from ordinary phonological disorder.”
The vowel is the tell

How language sample analysis contributes

A language sample contributes less than a structured motor speech examination because the diagnostic features of CAS — inconsistency, transitions, prosody — are not captured well in a 50-utterance narrative. However, sampling a diagnostic word list (e.g., the Dynamic Evaluation of Motor Speech Skill) on three separate days and running PCC and consistency metrics across sessions is part of the clinical workup. Transcribe phonetically, annotate vowel errors and stress patterns, and compute the proportion of tokens that change between sessions. Pair with intelligibility-to-strangers ratings for severity.

Free tools for Childhood Apraxia of Speech (CAS)

Articulation Screener

Free interactive articulation screener for speech-language pathologists. Tick errored sounds on a 30-word single-word probe covering every English consonant in at least one word position (initial, medial, final). The tool lists every errored sound, groups errors by position, and flags whether each sound is age-expected or past its McLeod & Crowe (2018) age of mastery — headline pass / at-cusp / refer decision in one keystroke. Modelled on the Goldman-Fristoe Test of Articulation 3 sounds-in-words structure and the Iowa-Nebraska norms (Smit et al. 1990). Mobile-friendly, client-side, no sign-up.

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PCC Calculator

Free interactive Percent Consonants Correct (PCC) calculator for speech-language pathologists. Enter the consonants attempted and produced correctly from a 50- to 100-utterance connected-speech sample and get the PCC percent plus the Shriberg & Kwiatkowski (1982) severity band (mild, mild-moderate, moderate-severe, severe). Built for SLP intake, IEP eligibility, treatment-progress tracking, and graduate phonological-assessment training. Mobile-friendly, client-side, no sign-up.

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Speech Intelligibility by Age Calculator

Free interactive speech intelligibility calculator for speech-language pathologists. Enter a child age and the observed unfamiliar-listener intelligibility percent from a connected-speech sample, and the tool returns the typical / borderline / refer flag against the pooled Coplan & Gleason (1988), Flipsen (2006), and Hustad et al (2021) age expectations. Built for SLP intake, well-child visits, EI eligibility, and parent counselling. Mobile-friendly, client-side, no sign-up.

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Related disorders

Pediatric

Articulation Disorder

An articulation disorder involves isolated difficulty producing specific speech sounds correctly, typically with intact phonological representation.

Pediatric

Phonological Disorder

Phonological disorder is characterised by rule-based speech sound error patterns — entire classes of sounds affected in predictable ways — rather than isolated mis-articulations.

Lifespan

Dysarthria

Dysarthria is a motor speech disorder caused by muscle weakness or incoordination affecting respiration, phonation, articulation, resonance, and prosody.

References

  1. American Speech-Language-Hearing Association. (2007). Childhood Apraxia of Speech [Technical Report]. ASHA.
  2. Shriberg, L. D., Aram, D. M., & Kwiatkowski, J. (1997). Developmental apraxia of speech: III. A subtype marked by inappropriate stress. JSLHR, 40(2), 313–337.
  3. Strand, E. A. (2020). Dynamic temporal and tactile cueing: A treatment strategy for childhood apraxia of speech. AJSLP, 29(1), 30–48.