Investigating Influences of Medial Olivocochlear Efferent System on Central Auditory Processing and Listening in Noise: A Behavioral and Event-Related Potential Study

Abstract

<jats:p>This electrophysiological study investigated the role of the medial olivocochlear (MOC) efferents in listening in noise. Both ears of eleven normal-hearing adult participants were tested. The physiological tests consisted of transient-evoked otoacoustic emission (TEOAE) inhibition and the measurement of cortical event-related potentials (ERPs). The mismatch negativity (MMN) and P300 responses were obtained in passive and active listening tasks, respectively. Behavioral responses for the word recognition in noise test were also analyzed. Consistent with previous findings, the TEOAE data showed significant inhibition in the presence of contralateral acoustic stimulation. However, performance in the word recognition in noise test was comparable for the two conditions (i.e., without contralateral stimulation and with contralateral stimulation). Peak latencies and peak amplitudes of MMN and P300 did not show changes with contralateral stimulation. Behavioral performance was also maintained in the P300 task. Together, the results show that the peripheral auditory efferent effects captured via otoacoustic emission (OAE) inhibition might not necessarily be reflected in measures of central cortical processing and behavioral performance. As the MOC effects may not play a role in all listening situations in adults, the functional significance of the cochlear effects of the medial olivocochlear efferents and the optimal conditions conducive to corresponding effects in behavioral and cortical responses remain to be elucidated.</jats:p>

No Change in Medial Olivocochlear Efferent Activity during an Auditory or Visual Task: Dual Evidence from Otoacoustic Emissions and Event-Related Potentials

“…Even though we ensured good quality measurements with high SNRs, we did not find a difference between tasks (unlike in some previous experiments). This is in line with some other studies that failed to confirm earlier reported effects on the MOC reflex, for example, there are studies that have failed to show any connection between the MOC reflex and gender or laterality [ 46 ], adaptation to noise and central auditory processing [ 39 , 40 ], auditory processing disorders [ 47 ], tinnitus [ 48 ], or sickle cell disease [ 49 ]. Specifically, it has been suggested that previous work on auditory processing disorders probably did not fulfill appropriate SNR criteria in order to ensure reliability [ 47 ].…”

“…Furthermore, in these papers, the procedures vary significantly. For example, the recent study by Rao et al [ 40 ] showed no connection between P3 and OAE suppression when listening in noise. The present results might be more closely related to a study by Dragicevic et al [ 17 ] who showed some correlations in the modulation of OAEs and ERPs, although these were of a different kind than in the present study.…”

Brainstem auditory physiology in children with listening difficulties,

“…A recent investigation by Rao, Koerner, Madsen, and Zhang (2020) in adults reported no significant effect of contralateral MOCR activation on auditory cortical responses or on a nonsense word recognition in noise task. They concluded that the MOCR may not play a primary role in higher level processing of speech in noise perception.…”

Listening in complex acoustic scenes

“…Furthermore, measurements of otoacoustic emissions indicate that post-adaptation improvements in sensitivity to amplitude modulation for tones presented in noise are unlikely to be due to an efferent-dependent reduction in cochlear responses [ 20 ]. Nevertheless, through their influence on outer hair cells, medial olivocochlear efferents can regulate cochlear gain and therefore the responses of auditory nerve fibers, and their role in listening in noise remains a controversial area [ 21 , 22 ].…”