Sexual Dimorphism in the Functional Development of the Cochlear Amplifier in Humans.
Srikanta K Mishra, Samantha Zambrano, Hansapani Rodrigo
PMID 33974790WHAT IT FOUND
Otoacoustic emissions in boys drop significantly between ages 4 and 12, while girls' emissions remain stable.
This suggests the cochlear amplifier matures differently in males during childhood, potentially driven by hormonal changes rather than middle ear structure.
Key findings
01SFOAE magnitudes significantly decreased with age in male children but not in female children.
02Female participants had higher SFOAE magnitudes than males, with a larger difference in adults than in children.
03Neither middle ear transmission nor efferent inhibition accounted for the observed sex differences in SFOAEs.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study is retrospective, using data collected for other purposes, which means certain variables could not be controlled. Measurements were taken from only one ear per participant, so ear-specific effects could not be fully assessed. The findings are limited to the 1000 Hz frequency region; sex differences in cochlear function may vary at other frequencies. Hormonal levels were not measured, so the proposed link between androgen exposure and OAE changes remains a hypothesis supported by indirect evidence.
The easy way to misread this
Do not interpret the lower SFOAE levels in older boys as a sign of hearing loss or cochlear damage. This study indicates that a decline in emission magnitude is a normal part of male cochlear development during childhood, distinct from pathology.