Contralateral Suppression Of Teoae In Patients With Tinnitus and Normal Hearing

Kamala Sarathy* and V Jaya

Received: October 25, 2017;   Published: November 03, 2017

DOI: 10.26717/BJSTR.2017.01.000492

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Abstract

Aim and Objectives : To evaluate functional integrity of Outer Hair Cells and Medial Olivocochlear system in the subjects having normal hearing with tinnitus and compare it with normal population and also to study the importance of Otoacoustic Emissions testing as an important objective tool in tinnitus evaluation.

Methods and Materials: A total of 20 subjects in the age range of 18 years to 57 years were considered for the study. They were categorised into two groups such as experimental group and control group. Experimental group consisted of 14 subjects with normal hearing having unilateral or bilateral tinnitus. The control group consisted of 6 age matched subjects having normal hearing without any tinnitus. All the subjects of both the groups underwent Pure Tone Audiometry testing and tinnitus evaluation. TEOAE testing and Contralateral Suppression of TEOAE were carried out.

Results: Among the 19 ears in the experimental group, TEOAE was absent in 10 ears (52.6%) and present in 9 ears (47.3%). Presence of contralateral suppression of TEOAE was observed in 6 ears (31.5%) and absence of contralateral suppression was noted in 13 ears (68.4%). It can be observed that most of patients in the experimental group had absent TEOAE and there is a subtle difference in the contralateral suppression of TEOAE between the experimental and control group.

Conclusion: In conclusion abnormal OAE in patients with tinnitus having normal hearing sensitivity indicate the cochlear dysfunction. Absence of suppression indicates Medial Olivocochlear system dysfunction. We also suggest that other auditory structures and mechanisms apart from OHC and MOC system may also be the reason for tinnitus generation as the results included patients with normal OAE and Contralateral suppression of OAE.The study helps to understand the role of OAE measures in evaluating the functional integrity of Outer Hair Cells and MOC system in subjects having tinnitus with normal hearing. It also highlight about the role of MOC system and cochlea in the generation of tinnitus.

Keywords: Tinnitus; CSOAE; TEOAE; MOC system; Outer Hair Cells

Abbrevation: OAEs: Otoacoustic Emissions; MOC: Medial Olivocochlear System; MNTB: Medial Nucleus of the Trapezoid Body; OHCs: Outer Hair Cells; TEOAE: Transient Evoked Otoacoustic Emissions

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