Histopathological Features of the Spiral Ganglion and Cochlear Nerve in Temporal Bones from Three Patients with Profound Hearing Loss

Abstract

In the following study the condition of the spiral ganglion and the cochlear nerve of ears from patients suffering from profound hearing loss is described. The number of spiral ganglion cells has been related to the clinical diagnosis. The number of spiral ganglion cells in the two temporal bones of a patient with Neomycin ototoxicity was almost normal. A reduction of less than one-third of spiral ganglion cells has been observed in the temporal bones of a child who died after a bacterial labyrinthitis. The temporal bone with a Mondini dysplasia revealed a pronounced reduction of ganglion cells of more than two-thirds. The cochlear nerve trunk in the internal auditory canal appeared normal in all three cases. The present findings are discussed in respect to the degenerative behaviour of the cochlear neural elements in human being compared to animals.

Key Words:

• human temporal bone histopathology
• profound deafness
• spiral ganglion cells
• Mondini dysplasia
• bacterial labyrinthitis
• Neomycin ototoxicity