The effect of organ of corti loss on ganglion cell survival in humans.
OBJECTIVE
Severe spiral ganglion cell loss does not necessarily follow loss of hair cells or supporting cells in humans.


BACKGROUND
Despite some publications to the contrary, statements that loss of hair cells and/or supporting cells of the organ of Corti results in a severe loss of spiral ganglion cells in humans still appear in the literature, especially in respect to cochlear implants. This assumption is apparently based on studies in animals or cell culture and not from studies of human temporal bones.


METHODS
Morphological analysis of archival temporal bones with microscopic and statistical analysis of ganglion cell, hair cell, and supporting cell populations was performed in 33 ears with total hearing losses of varying causes and durations of deafness. None of the ears had remaining hair cells. Six ears had had cochlear implants.


RESULTS
Ganglion cell counts ranging from 2,889 to 34,299 and the corresponding percentage of remaining ganglion cells based on age-normative data were not significantly related to the duration of hearing loss (r = -0.13 and 0.02, respectively, p > 0.05) or to remaining supporting cell populations (r's from 0.15 to 0.27, p > 0.05). More than half of ears (51.5%) had ganglion cell counts within two standard deviations of age-normative means. Mean ganglion cell counts and percentage of remaining ganglion cells of ears with surviving peripheral processes (dendrites) did not differ significantly from those of ears with no peripheral processes.


CONCLUSIONS
The loss of hair and supporting cells in the organ of Corti in humans does not necessarily result in as significant a loss of spiral ganglion cells as has been reported animals. In fact, our results suggest that ganglion cell loss may be a primary concomitant loss due to the disease process.
Teufert
Karen Borne
KB
Histopathology Department, House Ear Institute, Los Angeles, California 90057, USA. kteufert@hei.org
Linthicum
Fred H
FH
Connell
Sarah S
SS
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D002452:Cell Count; D002470:Cell Survival; D003054:Cochlear Implants; D005260:Female; D034381:Hearing Loss / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009925:Organ of Corti / Q000473:pathology*; D013136:Spiral Ganglion / Q000473:pathology*