Survival of Spiral Ganglion Cells in Profound Sensorineural Hearing Loss: Implications for Cochlear Implantation

1989 ◽  
Vol 98 (6) ◽  
pp. 411-416 ◽  
Author(s):  
Joseph B. Nadol ◽  
Yi-Shyang Young ◽  
Robert J. Glynn
Keyword(s):  
Hearing Loss ◽  
Ganglion Cell ◽  
Cell Count ◽  
Ganglion Cells ◽  
Spiral Ganglion ◽  
Bivariate Analysis ◽  
Spiral Ganglion Cell ◽  
Cell Counts ◽  
Profound Deafness ◽  
Temporal Bones

Ninety-three temporal bones from 66 patients who were profoundly deaf during life were reconstructed by analysis of serial light microscopic sections. The correlations of total and segmental spiral ganglion cell counts with age, duration of hearing loss and profound deafness, and cause of hearing loss were evaluated. Bivariate analysis demonstrated that total spiral ganglion cell count tended to be lower in older than in younger deaf individuals and lower with longer duration of hearing loss and total deafness. However, multiple regression analysis demonstrated that the cause of hearing loss was the single most significant determinant of total spiral ganglion cell count. Patients with deafness due to aminoglycoside toxicity or sudden idiopathic deafness had the highest residual spiral ganglion cell count and patients with deafness due to presumptive postnatal viral labyrinthitis, bacterial labyrinthitis, and congenital or genetic causes had the lowest numbers of residual spiral ganglion cells.

Effect of Cochlear Implantation on Residual Spiral Ganglion Cell Count as Determined by Comparison with the Contralateral Nonimplanted Inner Ear in Humans

2005 ◽  
Vol 114 (5) ◽  
pp. 381-385 ◽  
Author(s):  
Aayesha M. Khan ◽  
Ophir Handzel ◽  
Donald K. Eddington ◽  
Doris Damian ◽  
Joseph B. Nadol
Keyword(s):  
Cochlear Implant ◽  
Ganglion Cell ◽  
Cell Count ◽  
Ganglion Cells ◽  
Spiral Ganglion ◽  
Apical Segment ◽  
Spiral Ganglion Cell ◽  
Cell Counts ◽  
The Mean ◽  
Temporal Bones

It is generally assumed that at least a minimal number of spiral ganglion cells is essential for successful speech perception with a cochlear implant. Although the insertion of a multichannel cochlear implant frequently results in loss of residual hearing in the implanted ear, this outcome does not imply that significant damage to residual populations of spiral ganglion cells has occurred. The purpose of the current study was to compare spiral ganglion cell counts in implanted and nonimplanted cochleas in 11 patients for whom both temporal bones were available and in whom a multichannel cochlear implant had been placed unilaterally. The temporal bones were processed for light microscopy by standard techniques. The cochleas were reconstructed by 2-dimensional methods. Spiral ganglion cell counts of the implanted and nonimplanted sides were compared by a paired t-test (2-tailed). The mean spiral ganglion cell counts for implanted and nonimplanted ears were not statistically different in the most basal three segments of the cochlea. However, the mean spiral ganglion cell count in segment 4 (apical segment) and the mean total spiral ganglion cell count were lower in the implanted cochleas than in the nonimplanted cochleas (p < .01). The results of this study suggest a modest decrease in the total spiral ganglion cell count in the implanted ears as compared to the nonimplanted ears, principally in the apical segment. Possible interpretations of this finding are discussed.

S240 – Human Cochlear Implant Histopathology

2008 ◽  
Vol 139 (2_suppl) ◽  
pp. P155-P155
Author(s):  
Helen Xu ◽  
Natasha Pollak ◽  
Sebahattin Cureoglu ◽  
Michael M Paparella
Keyword(s):  
Cochlear Implant ◽  
Ganglion Cell ◽  
Cell Population ◽  
Ganglion Cells ◽  
Clinical Performance ◽  
Spiral Ganglion ◽  
Spiral Ganglion Cell ◽  
Cell Counts ◽  
Temporal Bones ◽  
Normal Spiral

Objectives 1) To exam the histopathology of multichannel cochlear implant temporal bones. 2) To evaluate the relationship of residual spiral ganglion cell counts to clinical hearing performance. Methods 8 temporal bones from 4 cochlear implant patients were examined histologically. Paired comparisons were made between implanted and nonimplanted temporal bones. Clinical performance data was obtained from patient charts. Results There were varying amounts of inflammation (fibrosis and ossification) in the basal turn of the cochlear in all implanted temporal bones. Trauma to the facial nerve at facial recess site was noticed in 1 case. Compared with nonimplanted ears, 2 implanted bones with less than 10-year duration of implantation had no significant changes of spiral ganglion cell population. One case with prolong implant duration (15 years) showed about 36% decrease of spiral ganglion cells at the implanted site. The case with best speech recognition (89% with CID sentence) had the highest residual spiral ganglion cells (30% of normal spiral ganglion cell population). 2 cases with poor clinical performance (< 10% with CID sentence) had the residual spiral ganglion cells at 11% and 22%. The case with moderate clinical performance (30% with CID sentence) had 14% of normal spiral ganglion cell population. Surviving dendrites varied from 5% to 30% among 4 cases with no relationship to clinical performance. Conclusions Our findings suggest prolonged implantation may affect spiral ganglion cell population. There is no reverse relationship between residual spiral ganglion cells in implanted temporal bones to clinical speech performance observed from our limited cases.

Survival of Scarpa's Ganglion in the Profoundly Deaf Human

1993 ◽  
Vol 102 (6) ◽  
pp. 425-428 ◽  
Author(s):  
Charlotte M. Chiong ◽  
Robert J. Glynn ◽  
Wen-Zhuang Xu ◽  
Joseph B. Nadol
Keyword(s):  
Ganglion Cell ◽  
Ganglion Cells ◽  
Linear Regression Analysis ◽  
Spiral Ganglion ◽  
Normal Hearing ◽  
Auditory Brain Stem Response ◽  
Spiral Ganglion Cell ◽  
Cell Counts ◽  
Profound Deafness ◽  
Scarpa's Ganglion

The electrically evoked auditory brain stem response in some cochlear implant patients may be confounded by evoked potentials generated by vestibular neurons. The magnitude of this contribution to the response from the vestibular system is unknown, in part because the survival of cells within Scarpa's ganglion in profoundly deaf humans is unknown. Therefore, we undertook a quantitative study of Scarpa's ganglion in 48 deaf subjects who in life would have been candidates for cochlear implantation and in 5 subjects with normal hearing. The numbers of residual cells in both Scarpa's ganglion and the spiral ganglion in deaf subjects were significantly less than in individuals with normal hearing. Bivariate analysis demonstrated a highly significant positive correlation between cell counts of Scarpa's ganglion and the spiral ganglion. The durations of hearing loss and of profound deafness were negatively correlated with Scarpa's ganglion cell counts. However, in contrast to spiral ganglion cell survival, the cause of profound deafness did not predict the number of Scarpa's ganglion cells. Multiple linear regression analysis using a variety of clinical parameters demonstrated that the best predictor of the number of Scarpa's ganglion cells in profoundly deaf humans was the number of remaining spiral ganglion cells.

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.

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.

Histopathology of Cochlear Implants in Humans

2001 ◽  
Vol 110 (9) ◽  
pp. 883-891 ◽  
Author(s):  
Joseph B. Nadol ◽  
Barbara J. Burgess ◽  
Bruce J. Gantz ◽  
Newton J. Coker ◽  
Darlene R. Ketten ◽  
...  
Keyword(s):  
Ganglion Cell ◽  
Cochlear Implantation ◽  
Single Channel ◽  
Spiral Ganglion ◽  
Electrode Array ◽  
Speech Comprehension ◽  
Spiral Ganglion Cell ◽  
Cell Counts ◽  
Significant Difference ◽  
Temporal Bones

The insertion of an intrascalar electrode array during cochlear implantation causes immediate damage to the inner ear and may result in delayed onset of additional damage that may interfere with neuronal stimulation. To date, there have been reports on fewer than 50 temporal bone specimens from patients who had undergone implantation during life. The majority of these were single-channel implants, whereas the majority of implants inserted today are multichannel systems. This report presents the histopathologic findings in temporal bones from 8 individuals who in life had undergone multichannel cochlear implantation, with particular attention to the type and location of trauma and to long-term changes within the cochlea. The effect of these changes on spiral ganglion cell counts and the correlation between speech comprehension and spiral ganglion cell counts were calculated. In 4 of the 8 cases, the opposite, unimplanted ear was available for comparison. In 3 of the 4 cases, there was no significant difference between the spiral ganglion cell counts on the implanted and unimplanted sides. In addition, in this series of 8 cases, there was an apparent negative correlation between residual spiral ganglion cell count and hearing performance during life as measured by single-syllable word recognition. This finding suggests that abnormalities in the central auditory pathways are at least as important as spiral ganglion cell loss in limiting the performance of implant users.

scholarly journals Interaural comparison of spiral ganglion cell counts in profound deafness

2011 ◽  
Vol 282 (1-2) ◽  
pp. 56-62 ◽  
Author(s):  
Mohammad Seyyedi ◽  
Donald K. Eddington ◽  
Joseph B. Nadol
Keyword(s):  
Ganglion Cell ◽  
Spiral Ganglion ◽  
Spiral Ganglion Cell ◽  
Cell Counts ◽  
Profound Deafness

Analysis of Spiral Ganglion Cell Populations in Children with Normal and Pathological Ears

2002 ◽  
Vol 111 (12) ◽  
pp. 1059-1065 ◽  
Author(s):  
Makoto Miura ◽  
Barry E. Hirsch ◽  
Isamu Sando ◽  
Yorihisa Orita
Keyword(s):  
Ganglion Cell ◽  
Ganglion Cells ◽  
Spiral Ganglion ◽  
Cell Populations ◽  
Spiral Ganglion Cell ◽  
Pathological Conditions ◽  
Profound Deafness ◽  
The Mean ◽  
Group 2 ◽  
Group 1

This study analyzed features of total and segmental spiral ganglion cell populations in children with normal ears and those with various pathological conditions. Sixty-three human temporal bone specimens, obtained from 43 children 4 days to 9 years of age, were studied histopathologically. These specimens were divided into 5 diagnostic groups: group 1, normal ears (13 ears); group 2, congenital infectious diseases (13 ears); group 3, chromosomal aberrations (11 ears); group 4, multiple craniofacial anomalies with hereditary or genetic causes (21 ears); and group 5, perinatal and postnatal asphyxia (5 ears). Eighteen of the 63 ears had documented profound deafness. In either normal ears (group 1) or those with various pathological conditions (groups 2 through 5), the total number of ganglion cells did not change as a function of age during the first 10 years. The total number of ganglion cells was significantly larger in group 1 (33,702) than in each of groups 2, 3, 4, and 5 (p < .01), and the number was significantly larger in group 2 than in each of groups 4 and 5 (p < .01 and p < .05, respectively). The ratio of basal to apical ganglion cell populations remained constant in both normal and pathological ears. Each ratio of the number of basal and apical ganglion cells in groups 2, 3, 4, and 5 to the mean number in group 1 (basal and apical survival ratios) was at least approximately 40%. There was no statistical difference between these Two ratios in groups 2, 3, 4, and 5. The mean (±SD) total number of ganglion cells in ears with documented profound deafness was 15,417 ± 5,944, which is approximately 40% of those present in normal ears. Our results suggest that normally, cochlear neurons are completely present at birth and minimally regress during the first decade of life. In addition, although intergroup differences among various pathological groups were present, the majority of pathological ears had more than 10,000 spiral ganglion cells present. Cochlear implantation has gradually been recognized as an effective and reliable tool for rehabilitation of children who have profound deafness, even congenitally or prelingually deafened children. On the basis of the results obtained in this study, we discuss the implications for cochlear implantation in children.

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.

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