Evaluation of the Contralateral Acoustic Stimulation Test After Audiological Examination of the Central Auditory System in Individuals with Normal Hearing

Sercan Dogukan Yildiz ,Mustafa Yüksel ,Fatma Elif Kilinç

doi:10.7176/jhmn/87-06

Abstract

The aim of our study was to evaluate the contralateral acoustic stimulation tests of central auditory system after audiological examination of individuals with normal hearing. In this context, a number of criteria were considered for the determination of individuals with normal hearing. Normal hearing provides the ability to live independently in the social environment of an individual, and the level of hearing is considered necessary for enabling communication with the environment. A total of 15 individuals were included in our study. In all individuals, five different frequencies were obtained compared to the threshold for both ears. The frequencies were 1000 Hz, 1414 Hz, 2000 Hz, 2828 Hz and 4000 Hz; and the suppression thresholds were also measured. After audiological tests were performed for our study, the same measurements were repeated. Looking at the results of the study, a statistically significant difference was found between the measurement results for right and left ears in individuals with normal hearing (P<0.05). Result: In order to see the suppressive effect, the integrity of the neural structures must be preserved starting from the medial nucleus of the superior olivary complex and reaching the OHCs. According to the results obtained in our study, we can conclude that MOCR is active, and the central nervous system is not impaired after the audiological evaluation. However, it is thought that a further study should be conducted with a larger sample group in order to obtain more specific results. Keywords: Contralateral suppression, normal hearing, otoacoustic emissions DOI: 10.7176/JHMN/87-06 Publication date: March 31 st 2021

Highlights

Hearing is very important for individual development and interpersonal communication
In this study, we aimed to evaluate the efferent auditory systems in the right and left ears of individuals with normal hearing using contralateral acoustic stimulation test after audiological testing
Various techniques are used for evaluating brain functions of the neural region within the Central Nervous System

Summary

Introduction

Hearing is very important for individual development and interpersonal communication. Otoacoustic emissions (OAE) are sounds generated by the outer hair cells of the cochlea, which can be measured with the aid of a microphone placed in the external auditory canal The decrease in the emission responses in the ear, which are measured by sending loud noise to the contralateral ear, indicates the presence of the medial olivocochlear (MOC) reflex (Smith & Cone, 2015). Contralateral medial olivocochlear system (MOCS) efferents have a direct impact on the function of outer hair cells. In adults with normal hearing, contralateral noise increases the speech intelligibility due to the MOC reflex activated by exposure to the loud noise (Smith & Cone, 2015)

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