Supported by National Institute on Deafness and Other Communication Disorders (NIDCD) 1R01DC010154 (B.H.H.). The authors have no other funding, financial relationships, or conflicts of interest to disclose.
Round window closure affects cochlear responses to suprathreshold stimuli
Article first published online: 10 OCT 2013
Copyright © 2013 The American Laryngological, Rhinological and Otological Society, Inc.
Volume 123, Issue 12, pages E116–E121, December 2013
How to Cite
Cai, Q., Whitcomb, C., Eggleston, J., Sun, W., Salvi, R. and Hu, B. H. (2013), Round window closure affects cochlear responses to suprathreshold stimuli. The Laryngoscope, 123: E116–E121. doi: 10.1002/lary.24394
- Issue published online: 25 NOV 2013
- Article first published online: 10 OCT 2013
- Accepted manuscript online: 23 SEP 2013 04:47AM EST
- Manuscript Accepted: 13 AUG 2013
- Manuscript Revised: 31 JUL 2013
- Manuscript Received: 10 JUN 2013
- Round window;
- distortion product otoacoustic emission;
- acoustic startle reflex
The round window acts as a vent for releasing inner ear pressure and facilitating basilar membrane vibration. Loss of this venting function affects cochlear function, which leads to hearing impairment. In an effort to identify functional changes that might be used in clinical diagnosis of round window atresia, the current investigation was designed to examine how the cochlea responds to suprathreshold stimuli following round window closure.
Prospective, controlled, animal study.
A rat model of round window occlusion (RWO) was established. With this model, the thresholds of auditory brainstem responses (ABR) and the input/output (IO) functions of distortion product otoacoustic emissions (DPOAEs) and acoustic startle responses were examined.
Round window closure caused a mild shift in the thresholds of the auditory brainstem response (13.5 ± 9.1 dB). It also reduced the amplitudes of the distortion product otoacoustic emissions and the slope of the input/output functions. This peripheral change was accompanied by a significant reduction in the amplitude, but not the threshold, of the acoustic startle reflex, a motor response to suprathreshold sounds.
In addition to causing mild increase in the threshold of the auditory brainstem response, round window occlusion reduced the slopes of both distortion product otoacoustic emissions and startle reflex input/output functions. These changes differ from those observed for typical conductive or sensory hearing loss, and could be present in patients with round window atresia. However, future clinical observations in patients are needed to confirm these findings.
Level of Evidence
N/A. Laryngoscope, 123:E116–E121, 2013