scholarly journals Spiral ganglion cells and macrophages initiate neuro-inflammation and scarring following cochlear implantation

2015 ◽  
Vol 9 ◽  
Author(s):  
Esperanza Bas ◽  
Stefania Goncalves ◽  
Michelle Adams ◽  
Christine T. Dinh ◽  
Jose M. Bas ◽  
...  
Keyword(s):  
Cochlear Implantation ◽  
Ganglion Cells ◽  
Spiral Ganglion ◽  
Neuro Inflammation

Diameter of the Cochlear Nerve in Deaf Humans: Implications for Cochlear Implantation

1992 ◽  
Vol 101 (12) ◽  
pp. 988-993 ◽  
Author(s):  
Joseph B. Nadol ◽  
Wen-Zhuang Xu
Keyword(s):  
Ganglion Cell ◽  
Cell Count ◽  
Cochlear Implantation ◽  
Ganglion Cells ◽  
Cranial Nerves ◽  
Spiral Ganglion ◽  
Normal Hearing ◽  
Maximum Diameter ◽  
Eighth Nerve ◽  
Spiral Ganglion Cell

Although the parameters that are most important for postoperative speech perception in cochlear implantation have not been identified, it is assumed that the numbers of remaining cochlear neurons and spiral ganglion cells in the implanted deaf ears are critical. In this study, we evaluated the correlation of the maximum diameter of the cochlear and vestibular nerve trunks with the number of spiral ganglion cells in horizontal sections of the temporal bone of 42 patients who were profoundly deaf during life, and in 5 patients with normal hearing. The maximum diameters of the cochlear, vestibular, and eighth cranial nerves were significantly smaller in the deaf population as compared to normal-hearing controls. In addition, the counts of the remaining spiral ganglion cells were significantly correlated with the maximum diameter of the cochlear (p = .0006), vestibular (p = .001), and eighth cranial nerves (p = .0003). The regression equation estimated that 25% of the variance of the spiral ganglion cell count was predicted by the maximum diameter of the eighth nerve. Although the results of this study suggest that preoperative radiographic imaging of the diameter of the eighth nerve may be helpful in predicting the residual spiral ganglion cell count, the wide variability of diameters of the eighth nerve in hearing and deaf subjects militates against this theoretic usefulness.

Analysis of Intracochlear New Bone and Fibrous Tissue Formation in Human Subjects with Cochlear Implants

2007 ◽  
Vol 116 (10) ◽  
pp. 731-738 ◽  
Author(s):  
Peter M. M. C. Li ◽  
Mehmet A. Somdas ◽  
Donald K. Eddington ◽  
Joseph B. Nadol
Keyword(s):  
Word Recognition ◽  
Cochlear Implantation ◽  
Ganglion Cells ◽  
Human Subjects ◽  
Fibrous Tissue ◽  
Spiral Ganglion ◽  
Tissue Formation ◽  
Spiral Ganglion Cell ◽  
Cell Counts ◽  
Temporal Bones

Objectives: In this study we aimed to evaluate new bone and new fibrous tissue formation in the inner ear following cochlear implantation. Methods: Twelve temporal bones from patients who underwent cochlear implantation during life were prepared for histologic study. The specimens were reconstructed by both 2-dimensional and 3-dimensional methods. These reconstructions were used to calculate the total volume and distribution of new bone and new fibrous tissue in the cochlea, the number of spiral ganglion cells, and other histopathologic parameters. Clinical data, including the last-recorded word recognition scores, were obtained from the patients' medical records. Results: New bone and new fibrous tissue were found in all 12 specimens, particularly at the site of cochleostomy. There was a significant correlation between overall damage to the lateral cochlear wall and the total volume of intracochlear new tissue (Spearman rho = .853; p = .0004). The total volume of new tissue did not correlate with word recognition scores or spiral ganglion cell counts. Conclusions: These preliminary results suggest that the degree of damage to the lateral cochlear wall may play an important role in influencing the amount of new tissue formation following cochlear implantation. Intracochlear new tissue does not appear to be an important determinant of performance as measured by word recognition scores or the total number of remaining spiral ganglion cells.

scholarly journals Long-Term Release of Dexamethasone With a Polycaprolactone-Coated Electrode Alleviates Fibrosis in Cochlear Implantation

2021 ◽  
Vol 9 ◽  
Author(s):  
Dongxiu Chen ◽  
Yanjing Luo ◽  
Jing Pan ◽  
Anning Chen ◽  
Dong Ma ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Cochlear Implantation ◽  
Treatment Effectiveness ◽  
Ganglion Cells ◽  
Spiral Ganglion ◽  
Related Factors ◽  
Electrode Coating ◽  
Promising Application ◽  
Major Treatment ◽  
The Stability

Cochlear implantation (CI) is the major treatment for severe sensorineural hearing loss. However, the fibrotic tissue forming around the electrodes reduces the treatment effectiveness of CI. Dexamethasone (DEX) is usually applied routinely in perioperative treatment of cochlear implantation (CI), but its diffusion in the inner ear after systemic administration is limited. In the present study, an electrode coated with polycaprolactone (PCL) loaded with dexamethasone was developed with a simple preparation process to maintain the stability of the electrode itself. The DEX-loaded PCL coating has good biocompatibility and does not change the smoothness, flexibility, or compliance of the implant electrode. Stable and effective DEX concentrations were maintained for more than 9 months. Compared with the pristine electrode, decreasing intracochlear fibrosis, protection of hair cells and spiral ganglion cells, and better residual hearing were observed 5 weeks after PCL-DEX electrode implantation. The PCL-DEX electrode has great potential in preventing hearing loss and fibrosis by regulating macrophages and inhibiting the expression of the fibrosis-related factors IL-1β, TNF-α, IL-4, and TGF-β1. In conclusion, the PCL-DEX electrode coating shows promising application in CI surgery.

scholarly journals Meta-Analysis—Correlation between Spiral Ganglion Cell Counts and Speech Perception with a Cochlear Implant

2021 ◽  
Vol 11 (2) ◽  
pp. 220-226
Author(s):  
Yew-Song Cheng ◽  
Mario A. Svirsky
Keyword(s):  
Speech Perception ◽  
Cochlear Implant ◽  
Ganglion Cells ◽  
Meta Analysis ◽  
Spiral Ganglion ◽  
Spiral Ganglion Cell ◽  
Cell Counts ◽  
Temporal Bones ◽  
The Relationship ◽  
Existing Data

The presence of spiral ganglion cells (SGCs) is widely accepted to be a prerequisite for successful speech perception with a cochlear implant (CI), because SGCs provide the only known conduit between the implant electrode and the central auditory system. By extension, it has been hypothesized that the number of SGCs might be an important factor in CI outcomes. An impressive body of work has been published on findings from the laborious process of collecting temporal bones from CI users and counting the number of SGCs to correlate those numbers with speech perception scores, but the findings thus far have been conflicting. We performed a meta-analysis of all published studies with the hope that combining existing data may help us reach a more definitive conclusion about the relationship between SGC count and speech perception scores in adults.

Otologic Histopathology of Fabry's Disease

1989 ◽  
Vol 98 (5) ◽  
pp. 359-363 ◽  
Author(s):  
Patricia A. Schachern ◽  
Michael M. Paparella ◽  
Donald A. Shea ◽  
Tae H. Yoon
Keyword(s):  
Temporal Bone ◽  
Ganglion Cells ◽  
Spiral Ganglion ◽  
Cell Loss ◽  
The Body ◽  
Spiral Ligament ◽  
Fabry’S Disease ◽  
Fabry's Disease ◽  
Temporal Bones ◽  
Spiral Ganglia

Fabry's disease is a rare progressive X-linked recessive disorder of glycosphingolipid metabolism. The accumulation of glycosphingolipids occurs in virtually all areas of the body, including the endothelial, perithelial, and smooth-muscle cells of blood vessels, the ganglion cells of the autonomic nervous system, and the glomeruli and tubules of the kidney. Although otologic symptoms have been described in these patients, to our knowledge there have been no temporal bone histopathologic reports. We describe the clinical histories, audiometric results, and temporal bone findings of two patients with this rare disorder. Both patients demonstrated a bilateral sloping sensorineural hearing loss audiometrically. Middle ear findings of seropurulent effusions and hyperplastic mucosa were seen in all four temporal bones. Strial and spiral ligament atrophy in all turns, and hair cell loss mainly in the basal turns, were also common findings. The number of spiral ganglion cells was reduced in all temporal bones; however, evidence of glycosphingolipid accumulation was not observed in the spiral ganglia.

Postnatal maturation of human spiral ganglion cells: Light and electron microscopic observations

1993 ◽  
Vol 67 (1-2) ◽  
pp. 211-219 ◽  
Author(s):  
Charlotte M. Chiong ◽  
Barbara J. Burgess ◽  
Joseph B. Nadol
Keyword(s):  
Ganglion Cells ◽  
Spiral Ganglion ◽  
Electron Microscopic ◽  
Postnatal Maturation

scholarly journals Histopathology of the Human Inner Ear in the Cogan Syndrome with Cochlear Implantation

2017 ◽  
Vol 22 (2) ◽  
pp. 116-123 ◽  
Author(s):  
Takefumi Kamakura ◽  
Daniel J. Lee ◽  
Barbara S. Herrmann ◽  
Joseph B. Nadol Jr.
Keyword(s):  
Bone Formation ◽  
Cochlear Implantation ◽  
Fibrous Tissue ◽  
Spiral Ganglion ◽  
New Bone Formation ◽  
Cogan Syndrome ◽  
Interstitial Keratitis ◽  
The Right ◽  
Ganglion Neurons ◽  
Temporal Bones

The Cogan syndrome is a rare disorder characterized by nonsyphilitic interstitial keratitis and audiovestibular symptoms. Profound sensorineural hearing loss has been reported in approximately half of the patients with the Cogan syndrome resulting in candidacy for cochlear implantation in some patients. The current study is the first histopathologic report on the temporal bones of a patient with the Cogan syndrome who during life underwent bilateral cochlear implantation. Preoperative MRI revealed tissue with high density in the basal turns of both cochleae and both vestibular systems consistent with fibrous tissue due to labyrinthitis. Histopathology demonstrated fibrous tissue and new bone formation within the cochlea and vestibular apparatus, worse on the right. Severe degeneration of the vestibular end organs and new bone formation in the labyrinth were seen more on the right than on the left. Although severe bilateral degeneration of the spiral ganglion neurons was seen, especially on the right, the postoperative word discrimination score was between 50 and 60% bilaterally. Impedance measures were generally higher in the right ear, possibly related to more fibrous tissue and new bone found in the scala tympani on the right side.

(−)-Epigallocatechin-3-gallate protects cultured spiral ganglion cells from H2O2-induced oxidizing damage

2004 ◽  
Vol 124 (4) ◽  
pp. 464-470 ◽  
Author(s):  
Dinghua Xie ◽  
Guohui Liu ◽  
Ganghua Zhu ◽  
Weijing Wu ◽  
Shenglei Ge
Keyword(s):  
Ganglion Cells ◽  
Spiral Ganglion

Brn3a is a transcriptional regulator of soma size, target field innervation and axon pathfinding of inner ear sensory neurons

Development ◽  
2001 ◽  
Vol 128 (13) ◽  
pp. 2421-2432 ◽  
Author(s):  
Eric J. Huang ◽  
Wei Liu ◽  
Bernd Fritzsch ◽  
Lynne M. Bianchi ◽  
Louis F. Reichardt ◽  
...  
Keyword(s):  
Inner Ear ◽  
Ganglion Cells ◽  
Substantial Reduction ◽  
Spiral Ganglion ◽  
Neurotrophin Receptor ◽  
Axon Pathfinding ◽  
Target Field ◽  
Afferent Fibers ◽  
Soma Size ◽  
Ganglion Neurons

The POU domain transcription factors Brn3a, Brn3b and Brn3c are required for the proper development of sensory ganglia, retinal ganglion cells, and inner ear hair cells, respectively. We have investigated the roles of Brn3a in neuronal differentiation and target innervation in the facial-stato-acoustic ganglion. We show that absence of Brn3a results in a substantial reduction in neuronal size, abnormal neuronal migration and downregulation of gene expression, including that of the neurotrophin receptor TrkC, parvalbumin and Brn3b. Selective loss of TrkC neurons in the spiral ganglion of Brn3a−/− cochlea leads to an innervation defect similar to that of TrkC−/− mice. Most remarkably, our results uncover a novel role for Brn3a in regulating axon pathfinding and target field innervation by spiral and vestibular ganglion neurons. Loss of Brn3a results in severe retardation in development of the axon projections to the cochlea and the posterior vertical canal as early as E13.5. In addition, efferent axons that use the afferent fibers as a scaffold during pathfinding also show severe misrouting. Interestingly, despite the well-established roles of ephrins and EphB receptors in axon pathfinding, expression of these molecules does not appear to be affected in Brn3a−/− mice. Thus, Brn3a must control additional downstream genes that are required for axon pathfinding.

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