Speech variability and prosody in childhood apraxia of speech

This is a follow-up to a paper that was presented at the 2014 Convention of the American Speech-Language-Hearing Association, which included preliminary data from 12 children. Data collection is ongoing and the data from all participants will be presented at the Acoustical Society of America Meeting in 2015. While speech variability and disordered prosody are core features of childhood apraxia of speech (CAS), much of the research in this area is descriptive and/or subjective. The purpose of the proposed study is to compare children with CAS to children with non-CAS speech sound disorders (SSDs) using more objective acoustic measures of variability and prosody, including: (1) durational variability of the phrase “Buy Bobby a puppy,” (2) durational variability of /ɑ/ in “Bobby,” (3) durational variability of /ʌ/ in “puppy,” (4) durational variability of voice onset time for /p/ in “puppy,” (5) spectral variability of the first and second formants (F1 and F2) for /ɑ/ in “Bobby,” (6) spectral variability of F1 and F2 for /ʌ/ in “puppy,” and (7) three stress metrics from Liss et al. (2009), which relate variability in consonant durations to variability in vowel durations and have been shown to differentiate between speakers with and without dysarthria and among different dysarthria subtypes. Preliminary data were encouraging. Children with CAS showed relatively more variability in consonant durations than vowel durations. Children with non-CAS SSDs showed relatively more variability in vowel durations than consonant durations.