Childhood Apraxia of Speech (CAS) is a rare pediatric motor speech disorder in which children have extreme difficulty learning to produce intelligible speech despite normal muscle function and desire to communicate. CAS is neurologically based: the child’s brain struggles to plan and program the precise sequences of movements for speech, resulting in errors that are highly inconsistent and pronounced difficulty combining sounds into syllables and words. Core features include: inconsistent errors on consonants and vowels, lengthened or disrupted coarticulatory transitions between sounds, and inappropriate prosody, especially in stress patterns.
Children with CAS often have severely limited speech intelligibility; in fact, CAS is an intractable speech disorder, affecting roughly 1 in 1,000 children. Early signs can include limited babbling as an infant, late first words, and the presence of only a small repertoire of consonant or vowel sounds. By the preschool years, these children’s speech remains very difficult to understand, which is when a definitive diagnosis is usually made by an SLP. Notably, CAS has been distinguished from other speech sound disorders because it does not typically resolve on its own; it reflects a fundamental problem in speech motor control, analogous to adult apraxia of speech but present from the start of speech development.
1. Genetic Factors: CAS often has a genetic basis, with studies identifying mutations in genes like FOXP2, GRIN2A, BCL11A, and KAT6A that are involved in speech-motor planning and neural signaling. These mutations can occur in isolation or as part of broader genetic syndromes, contributing to the speech sequencing difficulties seen in CAS.
2. Neurological Development: Although most children with CAS do not have visible brain lesions, neuroimaging studies show atypical development in speech-related networks such as Broca’s area and the supplementary motor area. These findings suggest that CAS arises from subtle disruptions in neural circuits responsible for planning and coordinating speech movements.
3. Developmental and Comorbid Conditions: CAS frequently co-occurs with other neurodevelopmental conditions, including autism spectrum disorder, ADHD, and epilepsy. The presence of these comorbidities indicates a more global developmental vulnerability, affecting motor coordination, language acquisition, and cognitive control in parallel.
Accurate diagnosis of CAS is essential, as its treatment differs significantly from other speech sound disorders. SLPs conduct comprehensive motor speech evaluations, assessing for inconsistent sound errors, disrupted coarticulatory transitions, and abnormal prosody. Once diagnosed, early and intensive intervention is recommended to maximize speech outcomes during critical periods of neural plasticity. Therapy typically involves motor-based approaches such as Dynamic Temporal and Tactile Cueing (DTTC) or Rapid Syllable Transition (ReST), which emphasize high repetition and movement precision. Sessions are often individualized and structured to gradually increase speech complexity with scaffolded support. Given the frequent co-occurrence of language, literacy, or cognitive impairments, interdisciplinary coordination is often necessary to address broader developmental needs. SLPs also play a key role in training families to implement carryover strategies at home and support communication through augmentative tools when needed.
Morgan, A. T., Fisher, S. E., Scheffer, I. E., et al. “Speech and Language Disorders: The Role of the FOXP2 Gene.” Frontiers in Neuroscience 14 (2020).
Formicola, D., et al. “Expanding the Molecular Landscape of Childhood Apraxia of Speech: Evidence From a Single-Center Experience.” Frontiers in Neuroscience 18 (2024).
Maassen, B. “Issues Contrasting Adult and Childhood Apraxia of Speech.” In Apraxia of Speech in Children: Theory and Practice, edited by A. L. Caruso & E. Strand, 25–52. New York: Thieme, 1999.
