Evidence for a Right-Ear Advantage in Newborn Hearing Screening Results

Area of Science:

• Audiology
• Neuroscience
• Developmental Biology

Background:

• Newborn hearing screening is crucial for early detection of hearing loss.
• Transient-evoked otoacoustic emissions (TEOAEs) are a common screening tool.
• Understanding factors influencing TEOAE results, like ear asymmetry, is important.

Purpose of the Study:

• To investigate the impact of ear asymmetry, testing order, and gender on TEOAE results in newborns.
• To determine if a right-ear advantage exists in TEOAE pass rates and response levels.
• To explore the relationship between these factors and auditory system lateralization.

Main Methods:

• Retrospective analysis of TEOAE screening data from 879 newborns.
• Comparison of pass rates and TEOAE characteristics between a study group (one-ear pass initially) and a control group (both-ear pass initially).
• Examination of the influence of which ear was tested first and infant gender.

Main Results:

• A significant right-ear advantage was observed, with higher pass rates (61% vs. 39%) and greater response amplitudes (1.75 dB) in the right ear.
• Testing the right ear first enhanced this advantage (76% pass rate).
• Females showed higher TEOAE amplitudes than males (1.5 dB), irrespective of ear or testing order.

Conclusions:

• The study confirms an innate right-ear advantage in TEOAEs, indicating functional lateralization of the auditory system at the cochlear level shortly after birth.
• Testing order significantly affects TEOAE pass rate asymmetry, but the innate right-ear advantage is a more dominant factor.
• Findings support early-onset auditory lateralization in both male and female infants.