Experimental autoimmune inner ear disease: An electrocochleographic and histophysiologic study

Systemic immunization with swine inner ear antigens in complete Freund's ad juvant induces functional disturbances in the cochlea. Morphometric data in dicate that an endolymphatic hydrops develops within 2 weeks. It diminishes 6 weeks after immunization. A progressive decrease in the compound action potential amplitude is observed from 2 to 6 weeks after immunization. Enhan cement of the amplitude of the summating potential is present without a cle ar overall correlation to the presence of endolymphatic hydrops. The amplit ude of the cochlear microphonics shows no significant changes after immuniz ation. Western blot analysis of the sera performed 2 and 6 weeks after immu nization shows enhanced reactivity at 68, 50, 45, and 27 kd molecular weigh ts, as compared to controls. The same spectrum of cross-reacting antibodies is believed to be instrumental in immune-mediated sensorineural hearing lo ss in patients. Apparently, cross-reacting antibodies and released mediator s disturb cochlear homeostasis, resulting in the observed changes in the el ectrophysiological responses. However, these changes are not clearly relate d to structural changes at the light and electron microscopic levels.