Lexical stress in childhood apraxia of speech: acoustic and kinematic findings

Hailey C. Kopera, Maria I. Grigos

Research output: Contribution to journalArticlepeer-review


Purpose: This study investigated the acoustic and articulatory movement parameters underlying lexical stress production in children with apraxia of speech (CAS), children with articulation/phonological delay (i.e. speech delay, SD), and children with typical speech-language development (TD). We examined whether there were group differences in these instrumental measures of stress production. Method: Participants were 24 children (seven CAS, eight SD, nine TD) between three and seven years of age. Acoustic and kinematic measures, including acoustic duration, peak and average fundamental frequency, and jaw movement duration and displacement, were taken from perceptually accurate productions of a strong-weak form. Relative stress analyses were conducted using the Pairwise Variability Index (PVI). Result: There was a significant difference between the CAS and TD groups in the PVI for movement duration, with the CAS group showing a smaller movement duration contrast between stressed and unstressed syllables. There were no significant group differences for displacement or any of the acoustic variables. Conclusion: The kinematic findings suggest reduced temporal control for lexical stress production in children with CAS. This finding surfaced during analyses of perceptually accurate productions but suggests a possible basis for lexical stress errors in CAS that could be explored in future studies.

Original languageEnglish (US)
Pages (from-to)12-23
Number of pages12
JournalInternational Journal of Speech-Language Pathology
Issue number1
StatePublished - Jan 2 2020


  • Childhood apraxia of speech (CAS)
  • acoustic measures
  • kinematic measures
  • lexical stress

ASJC Scopus subject areas

  • Research and Theory
  • Otorhinolaryngology
  • Language and Linguistics
  • LPN and LVN
  • Speech and Hearing


Dive into the research topics of 'Lexical stress in childhood apraxia of speech: acoustic and kinematic findings'. Together they form a unique fingerprint.

Cite this