The cochlear nuclei--pathology.

This article is a sequel to one dealing with the anatomy of the cochlear nuclei. It employs the combined peripheral/central approach in reviewing some basic principles of the pathology of central deafness, involving the cochlear nuclei. The combined approach shows the relative status of the cochlear elements and of the superior ventral cochlear nucleus in various conditions. Anoxic encephalopathy, including that of erythroblastosis, involves the stated nucleus but spares the peripheral hearing organ. This, as well as the findings in other conditions, reflects on the employment of amplification or the implantation of electrodes. The spheroid cells, the nerve cells of concern of the superior ventral cochlear nucleus (SVCN), show an anatomic frequency gradient, low ventral to high dorsal. In any case of deafness expected to involve the SVCN and showing an audiogram frequency pattern, the frequency gradient must be included in the pathologic investigation. When the organ of Corti is completely destroyed, the spheroid cells may show transsynaptic atrophy.