Effects of Device Limitations on Acquisition of the /t/-/k/ Contrast in Children With Cochlear Implants.
Allison A Johnson, Danielle M Bentley, Benjamin Munson and 1 others
PMID 34456300WHAT IT FOUND
Children with cochlear implants produced /t/ and /k/ less accurately than peers with normal hearing, but unlike typical development, they acquired both sounds at similar rates.
They also made unique errors, such as substituting affricates for stops, which suggests device limitations alter speech learning rather than just delaying it.
Key findings
01Children with cochlear implants produced target /t/ with 70% accuracy and target /k/ with 65% accuracy, compared to 93% and 92% respectively for children with normal hearing.
02Children with cochlear implants were more likely to produce manner errors, such as affricate substitutions, than children with normal hearing, whose errors were primarily voicing or place substitutions.
03Speech-language pathologists may find it useful to target manner of articulation before targeting place contrasts when treating children who use cochlear implants.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study did not include a hearing-age matched control group (children with NH with the same amount of auditory experience as the CI group), making it difficult to fully separate the effects of auditory deprivation from device limitations. The sample size was relatively small (26 per group). The analysis of spectral features was limited to correct productions, which may have obscured acoustic differences in incorrect tokens. The study focused only on the /t/-/k/ contrast; findings may not generalize to other speech sounds.
Declared interests
The authors declared no conflicts of interest, financial or otherwise. The study was supported by NIH and US Government grants.
The easy way to misread this
Do not conclude that cochlear implant users simply have delayed speech development. The unique error patterns observed, such as affricate substitutions and equal acquisition of /t/ and /k/, suggest that device limitations qualitatively alter how these children learn speech, requiring different therapeutic approaches than those used for typical developmental delays.