This competing grant renewal proposes continued study of the pathologic human inner ear following the basic strategy of the previous grant period, that is the use of light and electron microscopy. We plan a sharply focused area of investigation, namely cochlear neuronal degeneration in the human cochlear implant patient and its impact on speech recognition. We now have collected temporal bones from 16 individuals who were implanted during life. In nine of these, the auditory brainstem is also available. Initially we will plan to studythe implanted cochleas and morphometric parameters of thecochlear nucleus on both the stimulated and nonstimulated sides and to correlate these parameters with individual performance during life using the cochlear implant. Since the most dramatic central change might be expected in the neuropil of the cochlear nucleus, we also propose synaptophysin immunostaining to evaluate the density of synapses in the cochlear nucleus on stimulated and nonstimulated sides. This investigation can be expected to better predict remaining neuronal elements in human patients who are candidates for cochlear implantation and perhaps to explain the variability in speech recognition scores of these patients.

National Institute of Health (NIH)
National Institute on Deafness and Other Communication Disorders (NIDCD)
Research Project (R01)
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Special Emphasis Panel (ZRG1-IFCN-6 (01))
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Miller, Roger
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Massachusetts Eye and Ear Infirmary
United States
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Trakimas, Danielle R; Kozin, Elliott D; Ghanad, Iman et al. (2018) Human Otopathologic Findings in Cases of Folded Cochlear Implant Electrodes. Otol Neurotol 39:970-978
Kamakura, Takefumi; O'Malley, Jennifer T; Nadol Jr, Joseph B (2018) Preservation of Cells of the Organ of Corti and Innervating Dendritic Processes Following Cochlear Implantation in the Human: An Immunohistochemical Study. Otol Neurotol 39:284-293
O'Malley, Jennifer T; Burgess, Barbara J; Galler, Donald et al. (2017) Foreign Body Response to Silicone in Cochlear Implant Electrodes in the Human. Otol Neurotol 38:970-977
Kamakura, Takefumi; Lee, Daniel J; Herrmann, Barbara S et al. (2017) Histopathology of the Human Inner Ear in the Cogan Syndrome with Cochlear Implantation. Audiol Neurootol 22:116-123
Ishai, Reuven; Herrmann, Barbara S; Nadol Jr, Joseph B et al. (2017) The pattern and degree of capsular fibrous sheaths surrounding cochlear electrode arrays. Hear Res 348:44-53
Kamakura, Takefumi; Nadol Jr, Joseph B (2016) Correlation between word recognition score and intracochlear new bone and fibrous tissue after cochlear implantation in the human. Hear Res 339:132-41
Kamakura, Takefumi; Nadol Jr, Joseph B (2016) Cochlear Histopathology as Observed in Two Patients With a Cochlear Implant Electrode With Positioner. Otol Neurotol 37:642-6
Burgess, Barbara J; O'Malley, Jennifer T; Kamakura, Takefumi et al. (2016) Histopathology of the Human Inner Ear in the p.L114P COCH Mutation (DFNA9). Audiol Neurootol 21:88-97
Quesnel, Alicia M; Nakajima, Hideko Heidi; Rosowski, John J et al. (2016) Delayed loss of hearing after hearing preservation cochlear implantation: Human temporal bone pathology and implications for etiology. Hear Res 333:225-234
Nadol Jr, Joseph B; Handzel, Ophir; Amr, Sami (2015) Histopathology of the Human Inner Ear in a Patient With Sensorineural Hearing Loss Caused by a Variant in DFNA5. Otol Neurotol 36:1616-21

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