Evoked otoacoustic emissions and auditory selective attention

Area of Science:

• Neuroscience
• Auditory Neuroscience
• Psychoacoustics

Background:

• The auditory system features significant peripheral efferent innervation.
• The olivocochlear bundle (OCB) is an efferent system innervating cochlear outer hair cells (OHCs).
• Evoked otoacoustic emissions (EOAEs) reflect OHC micromechanical activity, serving as a potential measure of efferent system function.

Purpose of the Study:

• To determine if the OCB efferent system influences selective auditory attention.
• To investigate the relationship between attention, OCB function, and cochlear activity.

Main Methods:

• Six experiments utilized tone-pip EOAEs to compare cochlear responses to attended versus unattended auditory stimuli.
• A non-linear stimulus difference method isolated cochlear components of EOAEs.
• Attention was manipulated by varying task difficulty and presenting contralateral noise; stimuli were delivered to ipsilateral or contralateral ears.

Main Results:

• No significant effects of attention on EOAEs were observed across all six experiments.
• Results did not align with previously reported attention-related effects on cochlear activity.
• The study found no evidence supporting active cochlear involvement in selective attention under the tested conditions.

Conclusions:

• The findings from these experiments do not support the hypothesis that the OCB system plays an active role in selective auditory attention.
• Simple attention shifts between fixed auditory objects do not appear to modulate cochlear micromechanical properties via the OCB.