The influence of chronic vitamin A deficiency on human and animal ears.

After feeding young rats a diet deficient in vitamin A, we examined the inner ear with the electron microscope. There were changes in the cuticle of the outer and inner hair cells. Furthermore, there were changes in the reticular system of the intermediate zone and massive degenerative changes in the ganglion cells of the VIII nerve. In a second experiment with older animals we found no significant changes in the sensory cells, though there was new bone formation in Rosenthal's canal and damage to the ganglion cells, of a lesser extent than was evident in the first experiment, however. In a further clinical study, we carefully chose human subjects suffering from alcoholic liver disease who also had a negative history of ear infection, noise exposure, head injury and use of streptomycin. Normal auditory function in the family was also a criterion. A decreased auditory function associated with low vitamin A levels was found in these patients. Those with liver disease showed not only a significant auditory dysfunction in the higher frequencies, but as well a poorer performance in the tone decay test. They were compared to a control group with normal hepatic, renal and thyroid status.