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Vowel duration discrimination of children with CAS (Ingram et al., 2019)

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posted on 15.07.2019 by Susan B. Ingram, Vicki A. Reed, Thomas W. Powell
Purpose: The ability of 5- and 6-year-old male children (23 participants) between the chronological ages of 5;0 and 6;11(years;months) with childhood apraxia of speech (CAS; n = 9) and with typical development (TD; n = 14) to detect differences in vowel duration of syllable pairs is explored. We asked whether the children with CAS show different patterns of performance on the vowel duration difference experimental task than those of their similarly aged peers with TD.
Method: A male adult audio-recorded the syllable /bɑ/. The /ɑ/ was digitally lengthened and shortened, while maintaining uniform fundamental frequency and amplitude of the vowel and duration of the consonant /b/ at 42 ms. Vowel lengths increased in 40-ms increments, ranging from 208 to 488 ms. Eight pairs of syllables, 1 with equal length and 7 with differing vowel lengths, were randomly presented to the children 10 times in blocks of 16 pairs via a computer application.
Results: Numerous complementary analyses indicated patterns of performance differed for children with CAS compared to the children with TD. The children with CAS were notably less accurate in their duration discrimination and evidenced greater variability in their performances across duration difference conditions than their peers with TD, signifying they were generally challenged to discriminate the vowel duration differences.
Conclusion: These results suggest that CAS, which is more generally considered a motor speech disorder, may have a perceptual component of CAS related to vowel duration discrimination. Further research directions and clinical implications are discussed.

Supplemental Material S1. Individual child performances on the comprehensive assessment battery for children with typical development (TD) and childhood apraxia of speech (CAS).

Ingram, S. B., Reed, V. A., & Powell, T. W. (2019). Vowel duration discrimination of children with childhood apraxia of speech: A preliminary study. American Journal of Speech-Language Pathology, 28, 857–874.

Publisher Note: This article is part of the Special Issue: Selected Papers From the 2018 Conference on Motor Speech—Clinical Science and Innovations.