連続音による閾値上昇の臨床的観察

概要

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Slyghtly superliminal sustained tone was given by an ordinary pure tone audiometer with 5 db step attenuator, the threshold shift was measured at 1000 cps and 8000 cps. Normal per-sons, and those of perceptive deafness, conductive deafness and the patients who were treated with Streptomycin were subjected to this test. The results were as follows: 1) In patients of perceptive deafness, the threshold shift on sustained tone was observed. It was more distinct at 8000cps than at 1000cps. 2) Two types of the threshold shift were observed.Type I : Rapid threshold shift (over 20 db in 1 minute). Type II: Slow threshold shift (less than 15 db in 3 minutes). This type was observed not only in perceptive deafness but also in conductive deafness. 3) It has been reported that hearing impairment caused by administration of Streptomycin includes retro-labyrinthine deafness. But no difference was observed between the threshold shift of Streptomycin deafness and other perceptive deafnesses. 4) 50% of the patients who had been given Streptomycin causing no hearing impairment revealed threshold shift on sustained tone. This group belongs to Type II. 5) In a case of acute perceptive deafness which showed rapid threshold shift, * disappea-rance of this phenomenon was observed in proportion to the restoration of the hearing acuity.
社団法人日本耳鼻咽喉科学会の論文