Contralateral suppression of otoacoustic emissions in neonates

The effect of contralateral acoustic stimulation on transient evoked otoacoustic emissions (TEOAEs) was used to investigate the activity of the medial olivocochlear bundle in neonates. TEOAEs were bilaterally recorded, with and without contralateral noise, in 120 full-term neonates without risk for hearing loss. Otoacoustic emission recordings were carried out using the Otodynamic ILO88 system quickscreener non-linear mode, and the contralateral stimulation was presented at 60 dB SPL delivered by CD player. The results revealed a significant (p<0.01) contralateral suppression of TEOAE response amplitude: 2.32 dB in females and 3.28 dB in males. This study shows that the suppression effect is present in 88.5% of neonates, with a gender difference (greater suppression in males) and frequency effect, suggesting a functional maturation of the medial olivocochlear bundle in the studied population.