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Front. Neurol. | doi: 10.3389/fneur.2018.01124

Abnormalities of Otoacoustic Emissions in Myasthenia Gravis: Association with Serological and Electrophysiological Features

  • 1Seoul National University Bundang Hospital, South Korea
  • 2Dongguk University Ilsan Hospital, South Korea
  • 3Seoul National University Hospital, South Korea
  • 4Hallym University, College of Medicine, South Korea

Objective: To investigate whether otoacoustic emissions (OAEs) are impaired in patients with myasthenia gravis (MG) and whether such dysfunction is associated with serological and electrophysiological features of MG.
Methods: We tested 15 patients with MG (30 ears) and 10 healthy age- and sex-matched subjects (20 ears) for transiently evoked OAE (TEOAE) and distortion product OAE (DPOAE).
Results: Compared with controls, MG patients revealed a significant reduction in the amplitude of TEOAEs (p < 0.05) and DPOAEs at higher frequencies between 2,026 and 4,053 Hz (p < 0.05). In the subgroup analysis, TEOAE and DPOAE amplitudes were significantly lower in the acetylcholine receptor (AChR) antibody-positive group (p < 0.05) as well as in the repetitive nerve stimulation (RNS)-positive (p < 0.05) group. In particular, the OAE alteration significantly correlated with anti-AChR antibody titers. No significant difference of the OAEs was found between thymomatous and non-thymomatous MG or between purely ocular and generalized MG.
Conclusions: Our study confirms that OAEs reveal subclinical dysfunction of the cholinergic neurotransmission of cochlear outer hair cells and correlate well with electrophysiological and serological characteristics of MG patients. Our findings imply that the measurement of OAEs might increase the diagnostic accuracy and help to monitor the severity of MG.

Keywords: Myasthenia Gravis, Otoacoustic emissions (OAEs), Outer hair cells (OHCs), cholinergic transmission, Nicotinic acethylcholine receptor (nAChR)

Received: 16 Jul 2018; Accepted: 06 Dec 2018.

Edited by:

Ghazala Hayat, Saint Louis University, United States

Reviewed by:

Gerald Pfeffer, University of Calgary, Canada
Denis Kudryavtsev, Institute of Bioorganic Chemistry (RAS), Russia  

Copyright: © 2018 Choi, Kim, Park, Cho, Lee, Kim and Park. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. Kyung Seok Park, Seoul National University Bundang Hospital, Seoul, South Korea, kpark78@naver.com