TY - JOUR
T1 - The effect of cochlear-implant-mediated electrical stimulation on spiral ganglion cells in congenitally deaf white cats
AU - Chen, Iris
AU - Limb, Charles Joungwoon
AU - Ryugo, David K.
N1 - Funding Information:
The authors gratefully acknowledge the contributions of Erika Kretzmer, Karen Montey, Tan Pongstaphone, and San Yu. This work was supported by NIH grants DC000232 and DC005211, the Emma Liepmann Endowment Fund, and a grant from the Advanced Bionics Corporation. Dr. Limb is a consultant for Advanced Bionics Corporation and receives support for unrelated work.
PY - 2010/12
Y1 - 2010/12
N2 - It has long been observed that loss of auditory receptor cells is associated with the progressive degeneration of spiral ganglion cells. Chronic electrical stimulation via cochlear implantation has been used in an attempt to slow the rate of degeneration in cats neonatally deafened by ototoxic agents but with mixed results. The present study examined this issue using white cats with a history of hereditary deafness as an alternative animal model. Nineteen cats provided new data for this study: four normal-hearing cats, seven congenitally deaf white cats, and eight congenitally deaf white cats with unilateral cochlear implants. Data from additional cats were collected from the literature. Electrical stimulation began at 3 to 4 or 6 to 7 months after birth, and cats received stimulation for approximately 7 h a day, 5 days a week for 12 weeks. Quantitative analysis of spiral ganglion cell counts, cell density, and cell body size showed no marked improvement between cochlear-implanted and congenitally deaf subjects. Average ganglion cell size from cochlear-implanted and congenitally deaf cats was statistically similar and smaller than that of normal-hearing cats. Cell density from cats with cochlear implants tended to decrease within the upper basal and middle cochlear turns in comparison to congenitally deaf cats but remained at congenitally deaf levels within the lower basal and apical cochlear turns. These results provide no evidence that chronic electrical stimulation enhances spiral ganglion cell survival, cell density, or cell size compared to that of unstimulated congenitally deaf cats. Regardless of ganglion neuron status, there is unambiguous restoration of auditory nerve synapses in the cochlear nucleus of these cats implanted at the earlier age.
AB - It has long been observed that loss of auditory receptor cells is associated with the progressive degeneration of spiral ganglion cells. Chronic electrical stimulation via cochlear implantation has been used in an attempt to slow the rate of degeneration in cats neonatally deafened by ototoxic agents but with mixed results. The present study examined this issue using white cats with a history of hereditary deafness as an alternative animal model. Nineteen cats provided new data for this study: four normal-hearing cats, seven congenitally deaf white cats, and eight congenitally deaf white cats with unilateral cochlear implants. Data from additional cats were collected from the literature. Electrical stimulation began at 3 to 4 or 6 to 7 months after birth, and cats received stimulation for approximately 7 h a day, 5 days a week for 12 weeks. Quantitative analysis of spiral ganglion cell counts, cell density, and cell body size showed no marked improvement between cochlear-implanted and congenitally deaf subjects. Average ganglion cell size from cochlear-implanted and congenitally deaf cats was statistically similar and smaller than that of normal-hearing cats. Cell density from cats with cochlear implants tended to decrease within the upper basal and middle cochlear turns in comparison to congenitally deaf cats but remained at congenitally deaf levels within the lower basal and apical cochlear turns. These results provide no evidence that chronic electrical stimulation enhances spiral ganglion cell survival, cell density, or cell size compared to that of unstimulated congenitally deaf cats. Regardless of ganglion neuron status, there is unambiguous restoration of auditory nerve synapses in the cochlear nucleus of these cats implanted at the earlier age.
KW - auditory nerve
KW - cochlea
KW - cochlear nucleus
KW - cochleosaccular degeneration
KW - congenital deafness
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U2 - 10.1007/s10162-010-0234-3
DO - 10.1007/s10162-010-0234-3
M3 - Article
C2 - 20821032
AN - SCOPUS:78650175928
SN - 1525-3961
VL - 11
SP - 587
EP - 603
JO - JARO - Journal of the Association for Research in Otolaryngology
JF - JARO - Journal of the Association for Research in Otolaryngology
IS - 4
ER -