Date of Graduation

Spring 2017


Doctor of Audiology


Communication Sciences and Disorders

Committee Chair

Abdullah Jamos


olivocochlear bundle, cochlear microphonics, outer hair cells, cochlear processes, wideband noise, narrowband noise

Subject Categories

Speech Pathology and Audiology


In humans, activation of the olivocochlear bundle (OCB) can have a suppression or enhancement effect on cochlear processes. This phenomenon was studied via OCB activation effects on otoacoustic emissions (OAEs). However, it has been suggested that cochlear microphonics (CMs) can provide better, more detailed information regarding OCB function. In the present study, 22 normal hearing female subjects between the ages of 18-30 were recruited and the OCB was examined via the recording of CMs under changes in three conditions: OCB activating noise, stimulus polarity and stimulus frequency. Specifically, the present study examines the effects of activating wideband noise and narrowband noise centered at 1 and 0.5 kHz, presented contralaterally. CMs were elicited using 0.5 and 1 kHz tone bursts. Stimuli were presented using both condensation and rarefaction polarity. CM response amplitude for each condition was collected. Data analysis using repeated measures ANOVA revealed that OCB activation did not cause a significant change in the CM response. These results indicate that the recorded response may not have reflected activity from the apical end of the cochlea.


© Catherine Palmietto

Open Access