No abstract

No abstract

The authors observed eight cases of intermittent tinnitus which appeared during the course of recovery from peripheral facial nerve paralysis of various etiology. The tinnitus occurred whenever a certain mimicfacial muscle contracted voluntarily or involuntarily. Under the operating microscope, contraction of the stapedial muscle synchronous with-contraction of the mimic facial muscle was observed. The tinnitus had disappeared completely immediately after the tendon of the stapedial muscle was sectioned. Changes of the minimum audible threshold (air conduction) were measured in each case when the stapedial muscle contracted without sound stimulation, and the results were in accord with the results obtained from the theoretical and experimental works which had been reported by several authors. In a conclusion, the authors stressed the importance of the stapedial muscle tinnitus in the study of pathogenesis of tinnitus, facial nerve paralysis, as well as in the study of middle ear function.

The changes of the action potential (AP), the summating potential (SP) and cochlear microphonics (CM) were investigated in reference to the grade of endolymphatic hydrops produced by endolymphatic sac obliteration in guinea pigs. In a few cases with minimum endolymphatic hydrops, super-normal AP was obtained. With an increase of endolymphatic hydrops, CM responses were reduced although AP responses at intensive stimulation were maintained relatively well. It is thought that the polarity of positive SP, as observed in control, was influenced to deflect towards negative SP by an interaction between the increased degree of endolymphatic hydrops and the changes of the biochemical components of the inner ear fluids.

No abstract