Date of Graduation

Spring 2021


Doctor of Audiology


Communication Sciences and Disorders

Committee Chair

Wafaa Kaf


frequency-modulated, distortion product otoacoustic emissions, normal hearing, children, fine structure, amplitude, signal-to-noise ratio

Subject Categories

Speech Pathology and Audiology


Distortion-product otoacoustic emissions (DPOAEs) are objective tests of the integrity of the outer hair cells of the cochlea in response to a single-tone pair stimulus. Despite advances in DPOAEs test protocols and technology, there is little research about the use of frequency modulated tones to improve response characteristics. This study evaluates the efficacy of a new frequency modulated stimulus with multiple-tone pair DPOAEs (mDPOAEs) compared to the standard stimulus protocol for mDPOAEs to determine whether frequency modulation (FM) will achieve more robust and faster results. Normative data for this novel test protocol were obtained in 11 healthy normal-hearing children aged 3-6. Amplitude, signal-to-noise ratio, and testing time of mDPOAEs with and without FM were measured and compared. Results of repeated-measures ANOVA indicate that mDPOAEs frequency modulated responses show no significant differences in amplitude or testing time from standard mDPOAEs without FM. The mean signal-to-noise response (SNR) of mDPOAEs without FM is greater than the SNR of mDPOAEs with FM. However, results suggest that mDPOAEs with FM are less variable overall than standard mDPOAEs, which indicates that mDPOAE responses obtained with FM may be more reliable than standard mDPOAEs. This suggests that FM may reduce the influence of DPOAE fine structure variations on the detection of the presence of a DPOAE response, which may be beneficial in a clinical setting. Findings are affected by the small number of participants because of halting data collection due to COVID-19; more research is necessary to evaluate the application of frequency modulated mDPOAEs in children.


© Kathryn Arielle Vlietstra Baker

Open Access