Tinnitus due to Abnormal Contraction of Stapedial Muscle

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.