Role of otoacoustic emissions in the early detection and prevention of ototoxicity

Abstract

Introduction: Evaluating Otoacoustic Emissions (OAEs) is one of the audiological methods for ototoxicity monitoring. The absence of OAEs indicates cochlear damage. The aim of this study was to study the usefulness of OAEs in early detection and prevention of ototoxicity. Materials and Methods: A prospective, comparative study was conducted to evaluate Transient-Evoked OAEs (TEOAEs) and Distortion-Product OAEs (DPOAEs) as they relate to Pure Tone Audiometry (PTA) in cases of ototoxicity. Hearing assessments of study group of 55 individuals exposed to ototoxic drugs were evaluated and compared at regular intervals, within the group and with control group of 25 individuals using PTA, TEOAEs, and DPOAEs. The abnormal OAE responses were calculated as predictive of significant changes in PTA thresholds. Student's t-test (independent samples, two-tailed) and ANOVA used for analysis. Results: PTA thresholds in the study group remained unaffected in the first three follow-ups whereas TPOAEs and DPOAEs were both found affected at the third follow-up, in significant number of ears in the study group. Significantly lower PTA thresholds were found in study group only at the fourth follow-up. Conclusions: Changes in TEOAEs and DPOAEs precede changes in PTA thresholds in ototoxicity and have high sensitivity and specificity in predicting hearing loss in such cases.