Journal article
Delayed loss of hearing after hearing preservation cochlear implantation: Human temporal bone pathology and implications for etiology
Hearing research, Vol.333, pp.225-234
03/2016
DOI: 10.1016/j.heares.2015.08.018
PMCID: PMC4775460
PMID: 26341474
Abstract
After initially successful preservation of residual hearing with cochlear implantation, some patients experience subsequent delayed hearing loss. The etiology of such delayed hearing loss is unknown. Human temporal bone pathology is critically important in investigating the etiology, and directing future efforts to maximize long term hearing preservation in cochlear implant patients. Here we present the temporal bone pathology from a patient implanted during life with an Iowa/Nucleus Hybrid S8 implant, with initially preserved residual hearing and subsequent hearing loss. Both temporal bones were removed for histologic processing and evaluated. Complete clinical and audiologic records were available. He had bilateral symmetric high frequency severe to profound hearing loss prior to implantation. Since he was implanted unilaterally, the unimplanted ear was presumed to be representative of the pre-implantation pathology related to his hearing loss. The implanted and contralateral unimplanted temporal bones both showed complete degeneration of inner hair cells and outer hair cells in the basal half of the cochleae, and only mild patchy loss of inner hair cells and outer hair cells in the apical half. The total spiral ganglion neuron counts were similar in both ears: 15,138 (56% of normal for age) in the unimplanted right ear and 13,722 (51% of normal for age) in the implanted left ear. In the basal turn of the implanted left cochlea, loose fibrous tissue and new bone formation filled the scala tympani, and part of the scala vestibuli. Delayed loss of initially preserved hearing after cochlear implantation was not explained by additional post-implantation degeneration of hair cells or spiral ganglion neurons in this patient. Decreased compliance at the round window and increased damping in the scala tympani due to intracochlear fibrosis and new bone formation might explain part of the post-implantation hearing loss. Reduction of the inflammatory and immune response to cochlear implantation may lead to better long term hearing preservation post-implantation.
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•Human temporal bone pathology from a Hybrid cochlear implant patient is presented.•Months after implantation, his initially preserved residual hearing deteriorated.•Hair cell and cochlear neuron loss did not account for the delayed deterioration.•Intracochlear fibrosis and new bone formation was found in the implanted ear.•Intracochlear scarring may partly explain delayed post-implantation hearing loss.
Details
- Title: Subtitle
- Delayed loss of hearing after hearing preservation cochlear implantation: Human temporal bone pathology and implications for etiology
- Creators
- Alicia M Quesnel - Department of Otology and Laryngology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, 243 Charles Street, Boston, MA 02114, USAHideko Heidi Nakajima - Department of Otology and Laryngology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, 243 Charles Street, Boston, MA 02114, USAJohn J Rosowski - Department of Otology and Laryngology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, 243 Charles Street, Boston, MA 02114, USAMarlan R Hansen - University of Iowa Hospitals and Clinics, Department of Otolaryngology, 200 Hawkins Drive, Iowa City, IA 52242-1078, USABruce J Gantz - University of Iowa Hospitals and Clinics, Department of Otolaryngology, 200 Hawkins Drive, Iowa City, IA 52242-1078, USAJoseph B Nadol - Department of Otology and Laryngology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, 243 Charles Street, Boston, MA 02114, USA
- Resource Type
- Journal article
- Publication Details
- Hearing research, Vol.333, pp.225-234
- DOI
- 10.1016/j.heares.2015.08.018
- PMID
- 26341474
- PMCID
- PMC4775460
- NLM abbreviation
- Hear Res
- ISSN
- 0378-5955
- eISSN
- 1878-5891
- Publisher
- Elsevier B.V
- Grant note
- 5R01DC000152-33; 1U24DC013983-01; 5P50DC000242-29 / National Institutes of Health (http://dx.doi.org/10.13039/100000002)
- Language
- English
- Date published
- 03/2016
- Academic Unit
- Molecular Physiology and Biophysics; Neurosurgery; Otolaryngology
- Record Identifier
- 9984006356502771
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