The Present Status of the Mechanics of Sound Conduction in Its Relation to the Possible Correction of Conduction Deafness

Abstract

E. H. Weber in 1851 interpreted the middle ear apparatus as an impedance matching transformer which balanced the resistance differences between the medium of conduction (air) and the medium of reception (liquid). The interpretation implied that the apparatus must be effective for all audiofrequency levels. It was not accepted by otologists because it was known that in conduction deafness, greater functional disability is noted for the low than for the high frequencies. Recent developments support the Weber interpretation and indicate that this low pitch disability is not dependent on frequency limitations due to the pathology of the middle ear. Evidence will be submitted to show that where the sound conduction apparatus is nonfunctional the drum membrane damps the direct conduction through the air of the middle ear. A case will be reported on the replacement of the lost drum membrane and ossicles by a prosthesis patterned after the middle ear apparatus of the bird. The possibility of creating a soft spot in the otic capsule in cases where the stapes is “frozen” to the head so that a transformer prosthesis may be applied will be considered. The accepted idea of a mass shuttling in the labyrinth liquid as the mechanical factor essential to audition is opposed.