Ultrasonics and Progressive Deafness

Abstract

The solution of the very important and difficult problems presented by progressive deafness due to otosclerosis—its cause, prevention, and cure—is to be found in the biological implications and applications of the newly acquired and as yet incompletely correlated data in the field of ultrasonics. As there are light waves which are beyond the physiological range of human visual perception, there are sound waves that are imperceptible to the human ear—the ultrasonics. The most silent centrifuge has an ultrasonic specter extending to 100 000 cy/sec. The telephone bell produces frequencies to 50 000 cy/sec, powerful, but silent, imperceptible to us. The traffic of everyday life, in the train, bus, car, next to the audible noise, hides a tremendous amount of silent sound which is frightfully dangerous to our hearing organ. A significant fact of modern research is that the intensities of ultrasonics are of not primary importance in influencing the chemical changes in human proteins. Sonics and ultrasonics are equally able to provoke alteration in tissue proteins. Low frequencies of ultrasonics cause liquefaction of thixotropic gels. This occurrence leads to an increase of permeability of the cell membrane and thus advances chemical changes within the protein. The Ph changes are accompanied with a shift within the protein fractions. An increase of the gamma globulins, and a fibrotic trend of defense is in the making. The result of this happening is the structural changes in the living tissue (collagen, bone). The sonorous vibrations are passing from the air into the solid bone of the ossicular chain and into the water medium (liquor) of the labyrinth to arrive at the perceiving apparatus of the cochlea in the inner ear. The sound waves, by reaching new media, are partly reflected and partly transmitted, this according to the exerted resistance. The transferred energy from the air to the tissue is very small. The reflection by the different media can be considerable. The reflected ultrasonics have a damaging effect upon biological structures, because of sublimation of energetic effects (chemical thermic, etc.). Such considerable reflection occurs at the interface of bone medium (stapes) and water medium (the labyrinthin liquor). The body defense which tends to seal the spot of intrusion of ultrasonics develops a fibrotic diathesis. The first stone of this defense barrier is the first step toward the condition of deafness. At this topographic location of defense barrier (the oval window), the aural pathology has been recording for the last half-century the appearance of primary otosclerotic foci, without being able to give any satisfying explanation of their nature. The difficult problem of progressive deafness with its complexity of biological implication could not be understood until sufficient ultrasonic data have been explored and comprehended. The experimentally produced sclerosis by exposing living tissue to ultrasonic has enabled us to penetrate into this enigmatic condition.