Distortion Product Otoacoustic Emission and Tinnitus: Role of Outer Hair Cells in the Genesis of Tinnitus

Abstract

Background: This study aims to detect outer hair cell (OHC) function in patients with tinnitus, by comparing the otoacoustic emissions (OAEs) in tinnitus patients with normal hearing and normal-hearing subjects without tinnitus, thereby revealing the role of OHC in the generation of tinnitus. Methods: After approval by the local research and ethics committee, this study was done in the department of otolaryngology and associated hospitals, from April 2022 to January 2023. Consent was obtained from all the participants in the present work after explaining the test procedure. The study group included 60 subjects with bilaterally normal hearing to participate. They were classified into two groups: Group 1, i.e., the control group, comprised 30 subjects who were unaffected by tinnitus, whereas Group 2, i.e., the study group, comprised 30 subjects who were suffering from tinnitus. Basic audiological tests and OAE test were done on the respondents of both the groups followed by a comparison of outcomes. Results: The authors of the present study found a statistically significant difference between the amplitude and signal-to-noise ratio (SNR) of distortion product OAE (DPOAE) in tinnitus patients and the control group without tinnitus, suggesting that OHCs have a role in the generation of tinnitus. Conclusion: It can be concluded that OHC activity was reduced in patients with tinnitus, as detected by reduced DPOAE amplitude and SNR, suggesting that the dysfunction of OHCs can be attributable to the generation of tinnitus.