Human cochlear nucleus: comparison of Nissl-stained neurons from deaf and hearing patients.

In this study of the effects of deafness on the morphology of the human cochlear nuclei, non-parametric statistical analysis is used to quantify differences in sizes and shapes of neuron somata. Data on 81,007 neuron somata from 11 patients are presented, as well as the total volume and surface area of the cochlear nuclei. Soma size of deaf patients, especially postlinguistically deaf ones, was smaller than that of controls, but not significantly so; the same was true for total cochlear nucleus volume. The data also indicate a greater soma size on the right side (as well as a greater ventral cochlear nucleus volume), a caudal-to-rostral decrease in soma size, and a correlation between soma size and shape. The data base is being continually extended and in future will allow comparisons with measurements from patients suffering from various forms of hearing loss.