Date of Graduation

Spring 2022


Doctor of Audiology


Communication Sciences and Disorders

Committee Chair

Abdullah Jamos


While it is known the auditory efferent system contains two distinct subgroups – the medial olivocochlear nucleus (MOC) and the lateral olivocochlear nucleus (LOC) – not much is known regarding the function of the LOC in humans. This study aims to evaluate the effect of activating the lateral olivocochlear (LOC) neurons via contralateral broad band noise (CBBN) on electrocochleography responses. A ten-minute time-blocked paradigm was utilized to evaluate both the slow and fast effect of the LOC neurons. Recordings were obtained at four points within this ten-minute block both with and without the presence of 50 dB SPL CBBN to observe the difference in action potential (AP) amplitude and latency using three different stimulus presentation rates (11.1, 58.59, and 97.66 clicks/second). Significant enhancement of the AP amplitude was observed at all rates when CBBN was present. This finding supports the theory that the LOC does function to modulate afferent auditory responses in humans.


auditory efferent system, electrocochleography, lateral olivocochlear nucleus, enhancement, compound action potential

Subject Categories

Speech Pathology and Audiology


© Riley J. Rickman

Open Access