Dichotic listening and otoacoustic emissions: Shared variance between cochlear function and dichotic listening performance in adults with normal hearing

The present study investigated a possible connection between speech processing and cochlear function. Twenty-two subjects with age range from 18 to 39, balanced for gender with normal hearing and without any known neurological condition, were tested with the dichotic listening (DL) test, in which listeners were asked to identify CV-syllables in a nonforced, and also attention-right, and attention-left condition. Transient evoked otoacoustic emissions (TEOAEs) were recorded for both ears, with and without the presentation of contralateral broadband noise. The main finding was a strong negative correlation between language laterality as measured with the dichotic listening task and of the TEOAE responses. The findings support a hypothesis of shared variance between central and peripheral auditory lateralities, and contribute to the attentional theory of auditory lateralization. The results have implications for the understanding of the cortico-fugal efferent control of cochlear activity.

► Evoked otacoustic emissions (OAE) shows the integrity of the middle ear functions.
► Contra lateral noise yields suppression of the OAEs.
► This suppression shows efferent control of peripheral hearing.
► Attentional effects n dichotic listening (DL) is related to efferent control of OAE.
► The implications of this finding for contemporary models of DL is discussed.