Contralateral suppression of otoacoustic emission in patients with tinnitus

Mariana Lopes Fávero,Tanit Ganz Sanchez,Ricardo Ferreira Bento,Andreia Ferreira Nascimento

doi:10.1016/s1808-8694(15)30059-8

Abstract

SummaryIntroduction: The medial olivocochlear bundle effect is studied through the suppression of otoacoustic emissions and seems to be influenced by the laterality of the central nervous system, presenting no symmetry between right and left ear. A dysfunction of this bundle may be involved in the generation of tinnitus, although this fact was not confirmed. Objectives: Study the suppression of distortion product otoacoustic emissions in tinnitus patients. Material and Method: A case-controlled study involving 44 tinnitus patients from the Tinnitus Group of the ENT Department of the University of São Paulo Medical School and 44 controls who underwent distortion product otoacoustic emissions testing with and without contralateral noise. Only the results from the right ears from both groups were compared. Results: There was a relationship between the presence of tinnitus and the absence of suppression at all frequencies studied (OR>2.1). Conclusion: There was a correlation between diminished effectiveness of the medial olivocochlear bundle and the presence of tinnitus.

Highlights

Many theories have been conjured up in recent years in an attempt to explain the tinnitus origin
A dysfunction of the efferent system could lead to a loss in outer hair cells modulation, that is, this balance between hyperpolarization and depolarization, generating an abnormal and exaggerated electrical activity that may be misinterpreted as a sound by the Central Nervous System[1]
In order to measure the link between tinnitus and suppression absence in Distortion Product Otoacoustic Emissions (DPOAE) we compared the results between the right ears of tinnitus patients with those from controls, calculating the odds ratio (OR) for each frequency studied, as well as the respective confidence intervals (CI95%)

Summary

Introduction

Many theories have been conjured up in recent years in an attempt to explain the tinnitus origin. A dysfunction of the efferent system could lead to a loss in outer hair cells modulation, that is, this balance between hyperpolarization and depolarization, generating an abnormal and exaggerated electrical activity that may be misinterpreted as a sound by the Central Nervous System[1]. This modulation alteration may occur due to a specific lesion in the outer hair cells, causing a reduction in inhibitory efferent stimuli[9], or by an intrinsic balance alteration between the excitatory and inhibitory components, the former prevailing[10]

Objectives

Methods

Results

Conclusion