- The Society of Practical Otolaryngology
- 耳鼻咽喉科臨床 (ISSN:00326313)
- vol.74, no.4, pp.698-705, 1981
Sixteen patients with progressive bilateral perceptive deafness due to unknown causes were examined using various hearing tests and equilibrium tests with the following results.<br>1. Among the 11 patients examined 11 showed inner ear deafness and 3 showed inner ear deafness combined with retrocochlear one.<br>2. With reference to the appearance and progress of deafness, the deafness of this type was divided into the following two:<br>One was frequently observed in younger patients under twenty and was characterized by the tendency that bilateral deafness which appeared simultaneously and deteriorated equally, showed gradual, high-tone hearing loss. Thus, the hearing loss in these patients tended to be similar in pattern. i) between the first and the last examinations and ii) between the right and the left ears. Furthermore, the deafness of this type was rarely accompanied by vertiginous attacks.<br>The other was frequently found in older patients, of above twenty and was characterized by the tendency that deafness of both ears did not appear simultaneously and did not deteriorate equally. Furthermore, the deafness of this type was sometimes accompanied by vertiginous attacks in anamnesis.<br>3. Among the 16 patients examined, 4 showed fluctuating hearingloss. Furthermore, one of the 3 patients who underwent the glycerol test showed a positive sign. From the above mentioned findings the following conclusions were drawn:<br>(1) There may be differences between the 2 groups of patients, younger and older with regard to the etiological factors of the progressive bilateral perceptive deafness due to unknown causes, although both groups showed inner ear deafness. The deafness in the former group may be induced by congenital factors and may be regarded as a kind of premature presbyacusis. In contrast, the deafness in the later may be induced, at least partly, by acquired factors.<br>(2) Some patients showed findings suggestive of the existence of labyrinthine hydrops. These are valuable in considering the mechanism and treatment of the deafness of this type.