Repeated temporary threshold shift and changes in cochlear and neural function.

Autor: Morgan DS; University of Mississippi Medical Center, Department of Otolaryngology and Communicative Sciences, USA; University of Mississippi Medical Center, School of Medicine, USA., Arteaga AA; University of Mississippi Medical Center, Department of Otolaryngology and Communicative Sciences, USA., Bosworth NA; University of Mississippi Medical Center, Department of Otolaryngology and Communicative Sciences, USA; University of Mississippi Medical Center, School of Medicine, USA., Proctor G; University of Mississippi Medical Center, School of Medicine, USA., Vetter DE; University of Mississippi Medical Center, School of Medicine, USA; University of Mississippi Medical Center, Department of Neurobiology and Anatomical Sciences, USA., Lobarinas E; University of Texas at Dallas, School of Behavioral and Brain Sciences, USA., Spankovich C; University of Mississippi Medical Center, Department of Otolaryngology and Communicative Sciences, USA. Electronic address: cspankovich@umc.edu.
Jazyk: angličtina
Zdroj: Hearing research [Hear Res] 2019 Sep 15; Vol. 381, pp. 107780. Date of Electronic Publication: 2019 Aug 07.
DOI: 10.1016/j.heares.2019.107780
Abstrakt: A robust temporary threshold shift (TTS) can create significant primary damage to the auditory synapse, termed cochlear synaptopathy (CS). The common model applied to examination of this pathology is a single noise exposure or extended duration exposures at relatively high noise dosages. It is unclear if a single noise exposure that does not produce physiological changes consistent with CS (such as suppressed suprathreshold responses) can create evidence consistent with the pathology induced by repeated exposures. Here, we exposed 16-week (wk) old Sprague-Dawley rats to repeated noise exposures (4 consecutive days, 8-16 kHz octave-band of noise, 97 dB SPL for 2 h) and examined measures of cochlear function (distortion product otoacoustic emissions) and auditory neural integrity (auditory brainstem response, wave 1 amplitude). Our results demonstrated a mean maximal threshold shift of 16 dB at 24 h post the initial noise exposure. Subsequent daily repeated exposures (4 consecutive days) resulted in diminished threshold shift at 24 h post repeated TTS. In addition to recovered thresholds, no sustained reduction in suprathreshold responses was observed. The findings are consistent with conditioning literature suggesting diminished TTS with repeated exposures. Repeated TTS that was not individually synaptopathic did not produce physiological evidence consistent with acute CS.
(Copyright © 2019 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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