Profound Sensorineural Deafness: A Histopathologic Study

For this study 22 temporal bones from patients with profound sensorineural deafness of various causes were selected. Graphic reconstruction of each cochlea and acoustic ganglion was performed, together with a quantitative evaluation of three types of sensorineural elements: hair cells, peripheral auditory fibers, and ganglion cells. The numbers of acoustic ganglion cells were compared with those in 16 normal temporal bones. The temporal bones were divided into five groups, based on the relative degree of degeneration found in each of the three types of elements studied. Severe to complete hair cell loss was noted in all five groups; degeneration of peripheral nerve fibers ranged from moderate to complete in all but one group; and ganglion cell counts varied widely within all groups. In a qualitative comparison no relationship was found between the clinical data and the histopathologic correlates. The results of the study suggest that neither the clinical data nor the histopathologic findings provide any criteria for selecting patients for cochlear implants.