Journal article
Is cochlear synapse loss an origin of low-frequency hearing loss associated with endolymphatic hydrops?
Hearing research, Vol.398, pp.108099-108099
12/2020
DOI: 10.1016/j.heares.2020.108099
PMCID: PMC9058942
PMID: 33125982
Abstract
•Endolymphatic hydrops is associated with low-frequency hearing loss.•The origin of the low-frequency hearing loss is unknown.•Loss of cochlear synapses may be the origin of the low-frequency hearing loss.•We counted cochlear synapses in ears with hydrops and low-frequency hearing loss.•We did not find loss of cochlear synapses.
There is a strong association between endolymphatic hydrops and low-frequency hearing loss, but the origin of the hearing loss remains unknown. A reduction in the number of cochlear afferent synapses between inner hair cells and auditory nerve fibres may be the origin of the low-frequency hearing loss, but this hypothesis has not been directly tested in humans or animals. In humans, measurements of hearing loss and postmortem temporal-bone based measurements of endolymphatic hydrops are generally separated by large amounts of time. In animals, there has not been a good objective, physiologic, and minimally invasive measurement of low-frequency hearing. We overcame this obstacle with the combined use of a reliable surgical approach to ablate the endolymphatic sac in guinea pigs and create endolymphatic hydrops, the Auditory Nerve Overlapped Waveform to measure low-frequency hearing loss (≤ 1 kHz), and immunohistofluorescence-based confocal microscopy to count cochlear synapses. Results showed low- and mid-(1–4 kHz) frequency hearing loss at all postoperative days, 1, 4, and 30. There was no statistically significant loss of cochlear synapses, and there was no correlation between synapse loss and hearing function. We conclude that cochlear afferent synaptic loss is not the origin of the low-frequency hearing loss in the early days following endolymphatic sac ablation. Understanding what is, and is not, the origin of a hearing loss can help guide preventative and therapeutic development.
Details
- Title: Subtitle
- Is cochlear synapse loss an origin of low-frequency hearing loss associated with endolymphatic hydrops?
- Creators
- Carla V Valenzuela - Washington University in St. LouisChoongheon Lee - University of RochesterAbby Mispagel - Washington University in St. LouisAtri Bhattacharyya - Washington University in St. LouisShannon M Lefler - Washington University in St. LouisShelby Payne - Washington University in St. LouisShawn S Goodman - University of IowaAmanda J Ortmann - Washington University in St. LouisCraig A Buchman - Washington University in St. LouisMark A Rutherford - Washington University in St. LouisJeffery T Lichtenhan - Washington University in St. Louis
- Resource Type
- Journal article
- Publication Details
- Hearing research, Vol.398, pp.108099-108099
- DOI
- 10.1016/j.heares.2020.108099
- PMID
- 33125982
- PMCID
- PMC9058942
- NLM abbreviation
- Hear Res
- ISSN
- 0378-5955
- eISSN
- 1878-5891
- Publisher
- Elsevier B.V
- Language
- English
- Date published
- 12/2020
- Academic Unit
- Communication Sciences and Disorders
- Record Identifier
- 9984258848902771
Metrics
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