A study on diplacusis binauralis dysharmonica

Abstract

The author studied on the various basic methods to measure the difference of biaural pitches by using 35 healthy subjects. These methods were clinically applied to 1) 32 cases of Menieres disease 2) 10 cases of nerve deafness 3) 10 cases of conductive deafness, and following results were obtained. Of 32 cases of Ménières disease. 15 were fresh cases 17 were obsolete cases. 12 of 15 fresh cases and 2 of 17 obsolete cases revealed Pathological Diplacusis (Diplacusis index is over ±2%), In 15 cases of Pathological Diplacusis 12 cases showed higher pitch on diseased ear than on healthy side, and 3 cases showed the reverse. The former group has greater difference of the pitch of both ears. The audiogram of Pathological Diplacusis cases revealed reversible hearing loss of low frequency in most cases and closed relationship to Recruitment was seen. However, there noted no parallel relationship with Pitch Difference Limen. Therefore, above mentioned phenomenon is considered to be explained by disturbance of the sense of hearing due to Endolymphatic Hydrops. This phenomenon was not comfirmed at any other types of hard of hearing. © 1960, The Oto-Rhino-Laryngological Society of Japan, Inc. All rights reserved.