What do Lady Gaga and Jennifer Zuk’s all-star research team have in common? (Hint: not meat dresses nor poker faces). It’s their interest in the syllable “ga.” Let me explain. Zuk et al. have investigated the role that speech perception plays for children who have childhood apraxia of speech (CAS). Specifically, they utilized “ga-da” syllable discrimination tasks to assess the speech perception abilities of five different groups: typically developing children, children with CAS and co-occurring language impairment, children with CAS without a language impairment, children with only a language impairment, and children with only a speech delay. With the magic of technology, they synthesized a 41-step spectrum of syllables increasing in frequency from /ga/ to /da/. Pairs of syllables were presented to participants to determine the level at which they could perceive the smallest noticeable difference between the syllable stimuli. Discrimination thresholds were then recorded and the results of the groups were compared.
And so….. The CAS group without a language impairment performed similarly to the typically developing group. Both of these groups performed significantly better than both the CAS group with language impairment and the group with only a speech delay. These findings, thereby, suggest that poor speech perception difficulties noted in children with CAS are associated with an additional presence of language impairment and are not a core aspect of CAS as a sole diagnosis. An additional notable finding was related to the variability of results within the various groups. Children with CAS and no language impairment were quite homogeneous, whereas the children in the speech-delay and the language impairment groups displayed a wide range of responses.
Why the heck is this important? Well, the big take-home of this preliminary study is the notion that poor speech perception abilities do not seem to be a core aspect of a pure CAS diagnosis and, thus, are not deemed to contribute to motor planning difficulties. CAS children (when language skills are intact) have relatively strong speech perception abilities. Therefore, they are more apt to rely on auditory feedback, which can affect the delivery of intervention. In addition, Zuk’s findings illustrate the importance of accounting for language abilities when investigating CAS as components of a co-occurring language impairment could affect how CAS profiles and treatments are generated. As far as the variable speech perception abilities in the speech and language impairment groups, Zuk suggests that their relative heterogeneity underscores the need of further research to investigate if there are specific sub-profiles of speech and language that contribute to speech perception abilities. Although questions still remain regarding the link between speech perception and speech and language difficulties, what has been uncovered is that speech perception does not actually appear to be a core deficit in CAS….. or as Lady Gaga would put it, they have a “bad romance.”
Resources:
The Brains: Jennifer Zuk, Jenya Iuzzini-Seigel, Kathryn Cabbage, Jordan R. Green, Tiffany P. Hogan
The full article: Zuk, J., Iuzzini-Seigel, J., Cabbage, K., Green, J.R., & Hogan, T.P., (2018). Poor speech perception is not a core deficit of childhood apraxia of speech: preliminary findings. Journal of Speech, Language, and Hearing Research. 1-10
https://jslhr.pubs.asha.org/article.aspx?articleid=2673163Home
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