Contribution of Stimulus Variability to Word Recognition in Noise Versus Two-Talker Speech for School-Age Children and Adults.
Emily Buss, Lauren Calandruccio, Jacob Oleson and 1 others
PMID 32881723WHAT IT FOUND
In children, using the same target and masker pairings across trials made word recognition scores more consistent than changing them randomly.
In adults, consistency was similar regardless of whether stimuli were repeated or randomized. This supports using fixed stimuli when testing children's speech-in-speech recognition.
Key findings
01For children, the mean change in percent correct between two runs was 11.7 points with random stimuli and 6.9 points with frozen (repeated) stimuli, indicating greater reliability with frozen stimuli.
02For adults, the mean change in percent correct between two runs was 7.0 points with random stimuli and 7.1 points with frozen stimuli, showing no reliability benefit from freezing stimuli.
03Children required significantly more masked audibility (63.7% of epochs audible) to achieve 60-70% correct in a two-talker speech masker than adults (25.8%), suggesting different perceptual demands.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The order of conditions was not counterbalanced; children completed the random condition before the frozen condition, so the improved reliability in the frozen condition could partly reflect practice effects. The study used a small number of stimuli (30 words, 30 maskers), which limits the generalizability of the findings to larger clinical test corpora. The supplementary analysis with 15 adults was not included in the main regression models, limiting direct comparisons of reliability drivers across the full sample. One child’s data was excluded due to being an outlier, which may affect the stability of the child group results.
Declared interests
The stimuli and methods are under development as part of the Children’s English and Spanish Speech Recognition Test (ChEgSS). No specific funding sources or conflicts of interest were detailed in the provided text.
The easy way to misread this
Do not assume that freezing stimuli improves reliability for all ages. The benefit was observed only in children; adults showed no difference in consistency between random and frozen conditions. Additionally, because children performed the random task first, the apparent benefit of frozen stimuli might be influenced by practice rather than reduced stimulus variability alone.