Some pathologies of sensory and neural hearing loss.

Recently surgical implantation of devices to stimulate the auditory nerve in man makes it apparent that sensory and neural pathologies of deafness need to be differentiated from each other. In this paper 10 exemplary cases are presented. In addition, an attempt is made to compile the information now available about sensory and neural pathologies in the various diseases that cause deafness. Superficially, it would appear that most such entities are sensory in nature and thus theoretically might be amenable to auditory nerve stimulation. However, loss of supporting cells seems to be associated with cochlear nerve fibre degeneration. Many individuals may, therefore, eventually develop combined pathology. The paucity of knowledge of pathology of the auditory pathways and their radiations in deaf persons is recognized as a limiting factor in attempts to predict which patients might benefit from auditory nerve stimulation. It is not within the scope of this paper to delineate the possible deleterious effects that cochlear implants might have on the auditory nerve.