The Role of Interaural Differences, Head Shadow, and Binaural Redundancy in Binaural Intelligibility Benefits Among School-Aged Children.
Z Ellen Peng, Ruth Y Litovsky
PMID 34609935WHAT IT FOUND
School-aged children with normal hearing did not reach adult-like speech-in-noise performance by age 15.
The main gap was using timing and level differences between ears, while the head shadow effect was already mature.
Key findings
01Children's ability to understand sentences in noise improved between ages 6 and 15 but remained significantly poorer than adults at age 15.
02Head shadow provided the largest intelligibility benefit (7.5 dB), followed by interaural differences (4.2 dB) and binaural redundancy (0.6 dB).
03The difference between adults and children in overall speech-in-noise benefit was driven primarily by children's poorer use of interaural differences, not head shadow.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study used virtual auditory space with head-related transfer functions from a manikin rather than each child's own ears, though the authors note children could still use these cues effectively. The masker was a same-sex two-talker babble, which creates high informational masking and may not perfectly replicate all real-world classroom noise environments. Interaural difference benefits were derived mathematically by subtracting other cue benefits rather than being measured in isolation. The study included only children with normal hearing, so findings do not apply to children with hearing loss or auditory processing disorders.
Declared interests
The work was supported by NIH grants (National Institute on Deafness and Other Communication Disorders and Eunice Kennedy Shriver National Institute of Child Health and Human Development) and the University of Wisconsin-Madison. No commercial conflicts of interest are declared.
The easy way to misread this
Do not assume that a child with normal hearing thresholds processes speech in noise like an adult. This study shows that the ability to use binaural cues for speech-in-noise benefits continues to develop beyond age 15, so classroom noise can remain a significant barrier for older children.