Acoustic analysis of voicing errors in children with childhood apraxia of speech

Abstract

Childhood apraxia of speech (CAS) is a complex neurological speech sound disorder (SSD) that involves impaired speech motor planning and programming. Speech characteristics of CAS include difficulty sequencing speech movements in the absence of muscle weakness resulting in segmental and suprasegmental speech deficits. Past work indicates that children with CAS are delayed in acquisition of voicing contrasts, and are often perceived to produce errors or distortions of voicing. However, not all past studies employed acoustic analyses to assess voicing characteristics in CAS. This study will use voice onset time (VOT) to analyze the voicing contrast in children with CAS (aged 8;0 to 15;11) compared to peers with residual speech sound disorder (RSSD) and typical development (TD). VOT of initial consonants from twelve children (CAS = 4, RSSD = 4, TD = 4) will be assessed in words of varying length, stress pattern and target complexity. Given that children with CAS are known to experience greater articulatory breakdowns in phoneme sequences of increasing length and complexity, we expect that group differences will increase with task complexity. Overall, based on past work, we also predict that children with CAS will demonstrate shorter and/or more variable VOTs for plosives than children with SSD and TD.