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

TLDR

The study evaluated how total and segmental spiral ganglion cell counts correlate with age, duration of hearing loss, profound deafness, and etiology in profoundly deaf patients. Ninety-three temporal bones from 66 profoundly deaf patients were reconstructed via serial light microscopic section analysis. Total spiral ganglion cell counts were lower in older patients, with longer hearing loss, and total deafness, but the etiology of deafness was the strongest determinant, with aminoglycoside toxicity or sudden idiopathic deafness yielding the highest counts and postnatal viral, bacterial labyrinthitis, and congenital/genetic causes yielding the lowest.

Abstract

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.